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Paul Beesleyfc9ee362019-03-07 15:47:15 +00001Porting Guide
2=============
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003
Douglas Raillardd7c21b72017-06-28 15:23:03 +01004Introduction
5------------
6
Dan Handley610e7e12018-03-01 18:44:00 +00007Porting Trusted Firmware-A (TF-A) to a new platform involves making some
Douglas Raillardd7c21b72017-06-28 15:23:03 +01008mandatory and optional modifications for both the cold and warm boot paths.
9Modifications consist of:
10
11- Implementing a platform-specific function or variable,
12- Setting up the execution context in a certain way, or
13- Defining certain constants (for example #defines).
14
15The platform-specific functions and variables are declared in
Paul Beesleyf8640672019-04-12 14:19:42 +010016``include/plat/common/platform.h``. The firmware provides a default
Sandrine Bailleux7a53a912023-02-08 13:55:51 +010017implementation of variables and functions to fulfill the optional requirements
18in order to ease the porting effort. Each platform port can use them as is or
19provide their own implementation if the default implementation is inadequate.
20
21 .. note::
22
23 TF-A historically provided default implementations of platform interfaces
24 as *weak* functions. This practice is now discouraged and new platform
25 interfaces as they get introduced in the code base should be *strongly*
26 defined. We intend to convert existing weak functions over time. Until
27 then, you will find references to *weak* functions in this document.
Douglas Raillardd7c21b72017-06-28 15:23:03 +010028
Sandrine Bailleux2cea7942023-04-04 16:36:08 +020029Please review the :ref:`Threat Model` documents as part of the porting
30effort. Some platform interfaces play a key role in mitigating against some of
31the threats. Failing to fulfill these expectations could undermine the security
32guarantees offered by TF-A. These platform responsibilities are highlighted in
33the threat assessment section, under the "`Mitigations implemented?`" box for
34each threat.
35
Douglas Raillardd7c21b72017-06-28 15:23:03 +010036Some modifications are common to all Boot Loader (BL) stages. Section 2
37discusses these in detail. The subsequent sections discuss the remaining
38modifications for each BL stage in detail.
39
Sandrine Bailleuxdad35612022-11-08 13:36:42 +010040Please refer to the :ref:`Platform Ports Policy` for the policy regarding
41compatibility and deprecation of these porting interfaces.
Soby Mathew02bdbb92018-09-26 11:17:23 +010042
Antonio Nino Diaz645feb42019-02-13 14:07:38 +000043Only Arm development platforms (such as FVP and Juno) may use the
44functions/definitions in ``include/plat/arm/common/`` and the corresponding
45source files in ``plat/arm/common/``. This is done so that there are no
46dependencies between platforms maintained by different people/companies. If you
47want to use any of the functionality present in ``plat/arm`` files, please
Sandrine Bailleux8a1c0d62023-02-08 14:01:18 +010048propose a patch that moves the code to ``plat/common`` so that it can be
Antonio Nino Diaz645feb42019-02-13 14:07:38 +000049discussed.
50
Douglas Raillardd7c21b72017-06-28 15:23:03 +010051Common modifications
52--------------------
53
54This section covers the modifications that should be made by the platform for
55each BL stage to correctly port the firmware stack. They are categorized as
56either mandatory or optional.
57
58Common mandatory modifications
59------------------------------
60
61A platform port must enable the Memory Management Unit (MMU) as well as the
62instruction and data caches for each BL stage. Setting up the translation
63tables is the responsibility of the platform port because memory maps differ
Sandrine Bailleux6d981f72023-02-08 14:02:45 +010064across platforms. A memory translation library (see ``lib/xlat_tables_v2/``) is
Sandrine Bailleux1861b7a2017-07-20 16:11:01 +010065provided to help in this setup.
66
67Note that although this library supports non-identity mappings, this is intended
68only for re-mapping peripheral physical addresses and allows platforms with high
69I/O addresses to reduce their virtual address space. All other addresses
70corresponding to code and data must currently use an identity mapping.
71
Dan Handley610e7e12018-03-01 18:44:00 +000072Also, the only translation granule size supported in TF-A is 4KB, as various
73parts of the code assume that is the case. It is not possible to switch to
7416 KB or 64 KB granule sizes at the moment.
Douglas Raillardd7c21b72017-06-28 15:23:03 +010075
Dan Handley610e7e12018-03-01 18:44:00 +000076In Arm standard platforms, each BL stage configures the MMU in the
Douglas Raillardd7c21b72017-06-28 15:23:03 +010077platform-specific architecture setup function, ``blX_plat_arch_setup()``, and uses
78an identity mapping for all addresses.
79
80If the build option ``USE_COHERENT_MEM`` is enabled, each platform can allocate a
81block of identity mapped secure memory with Device-nGnRE attributes aligned to
82page boundary (4K) for each BL stage. All sections which allocate coherent
Chris Kay33bfc5e2023-02-14 11:30:04 +000083memory are grouped under ``.coherent_ram``. For ex: Bakery locks are placed in a
84section identified by name ``.bakery_lock`` inside ``.coherent_ram`` so that its
Douglas Raillardd7c21b72017-06-28 15:23:03 +010085possible for the firmware to place variables in it using the following C code
86directive:
87
88::
89
Chris Kay33bfc5e2023-02-14 11:30:04 +000090 __section(".bakery_lock")
Douglas Raillardd7c21b72017-06-28 15:23:03 +010091
92Or alternatively the following assembler code directive:
93
94::
95
Chris Kay33bfc5e2023-02-14 11:30:04 +000096 .section .bakery_lock
Douglas Raillardd7c21b72017-06-28 15:23:03 +010097
Chris Kay33bfc5e2023-02-14 11:30:04 +000098The ``.coherent_ram`` section is a sum of all sections like ``.bakery_lock`` which are
Douglas Raillardd7c21b72017-06-28 15:23:03 +010099used to allocate any data structures that are accessed both when a CPU is
100executing with its MMU and caches enabled, and when it's running with its MMU
101and caches disabled. Examples are given below.
102
103The following variables, functions and constants must be defined by the platform
104for the firmware to work correctly.
105
Javier Almansa Sobrino37bf69c2022-04-07 18:26:49 +0100106.. _platform_def_mandatory:
107
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100108File : platform_def.h [mandatory]
109~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100110
111Each platform must ensure that a header file of this name is in the system
Antonio Nino Diaz50a4d1a2019-02-01 12:22:22 +0000112include path with the following constants defined. This will require updating
113the list of ``PLAT_INCLUDES`` in the ``platform.mk`` file.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100114
Paul Beesleyf8640672019-04-12 14:19:42 +0100115Platform ports may optionally use the file ``include/plat/common/common_def.h``,
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100116which provides typical values for some of the constants below. These values are
117likely to be suitable for all platform ports.
118
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100119- **#define : PLATFORM_LINKER_FORMAT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100120
121 Defines the linker format used by the platform, for example
122 ``elf64-littleaarch64``.
123
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100124- **#define : PLATFORM_LINKER_ARCH**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100125
126 Defines the processor architecture for the linker by the platform, for
127 example ``aarch64``.
128
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100129- **#define : PLATFORM_STACK_SIZE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100130
131 Defines the normal stack memory available to each CPU. This constant is used
Paul Beesleyf8640672019-04-12 14:19:42 +0100132 by ``plat/common/aarch64/platform_mp_stack.S`` and
133 ``plat/common/aarch64/platform_up_stack.S``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100134
David Horstmann051fd6d2020-11-12 15:19:04 +0000135- **#define : CACHE_WRITEBACK_GRANULE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100136
Max Yufa0b4e82022-09-08 23:21:21 +0000137 Defines the size in bytes of the largest cache line across all the cache
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100138 levels in the platform.
139
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100140- **#define : FIRMWARE_WELCOME_STR**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100141
142 Defines the character string printed by BL1 upon entry into the ``bl1_main()``
143 function.
144
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100145- **#define : PLATFORM_CORE_COUNT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100146
147 Defines the total number of CPUs implemented by the platform across all
148 clusters in the system.
149
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100150- **#define : PLAT_NUM_PWR_DOMAINS**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100151
152 Defines the total number of nodes in the power domain topology
153 tree at all the power domain levels used by the platform.
154 This macro is used by the PSCI implementation to allocate
155 data structures to represent power domain topology.
156
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100157- **#define : PLAT_MAX_PWR_LVL**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100158
159 Defines the maximum power domain level that the power management operations
160 should apply to. More often, but not always, the power domain level
161 corresponds to affinity level. This macro allows the PSCI implementation
162 to know the highest power domain level that it should consider for power
163 management operations in the system that the platform implements. For
164 example, the Base AEM FVP implements two clusters with a configurable
165 number of CPUs and it reports the maximum power domain level as 1.
166
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100167- **#define : PLAT_MAX_OFF_STATE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100168
169 Defines the local power state corresponding to the deepest power down
170 possible at every power domain level in the platform. The local power
171 states for each level may be sparsely allocated between 0 and this value
172 with 0 being reserved for the RUN state. The PSCI implementation uses this
173 value to initialize the local power states of the power domain nodes and
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100174 to specify the requested power state for a PSCI_CPU_OFF call.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100175
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100176- **#define : PLAT_MAX_RET_STATE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100177
178 Defines the local power state corresponding to the deepest retention state
179 possible at every power domain level in the platform. This macro should be
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100180 a value less than PLAT_MAX_OFF_STATE and greater than 0. It is used by the
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100181 PSCI implementation to distinguish between retention and power down local
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100182 power states within PSCI_CPU_SUSPEND call.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100183
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100184- **#define : PLAT_MAX_PWR_LVL_STATES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100185
186 Defines the maximum number of local power states per power domain level
187 that the platform supports. The default value of this macro is 2 since
188 most platforms just support a maximum of two local power states at each
189 power domain level (power-down and retention). If the platform needs to
190 account for more local power states, then it must redefine this macro.
191
192 Currently, this macro is used by the Generic PSCI implementation to size
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100193 the array used for PSCI_STAT_COUNT/RESIDENCY accounting.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100194
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100195- **#define : BL1_RO_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100196
197 Defines the base address in secure ROM where BL1 originally lives. Must be
198 aligned on a page-size boundary.
199
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100200- **#define : BL1_RO_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100201
202 Defines the maximum address in secure ROM that BL1's actual content (i.e.
203 excluding any data section allocated at runtime) can occupy.
204
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100205- **#define : BL1_RW_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100206
207 Defines the base address in secure RAM where BL1's read-write data will live
208 at runtime. Must be aligned on a page-size boundary.
209
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100210- **#define : BL1_RW_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100211
212 Defines the maximum address in secure RAM that BL1's read-write data can
213 occupy at runtime.
214
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100215- **#define : BL2_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100216
217 Defines the base address in secure RAM where BL1 loads the BL2 binary image.
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000218 Must be aligned on a page-size boundary. This constant is not applicable
219 when BL2_IN_XIP_MEM is set to '1'.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100220
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100221- **#define : BL2_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100222
223 Defines the maximum address in secure RAM that the BL2 image can occupy.
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000224 This constant is not applicable when BL2_IN_XIP_MEM is set to '1'.
225
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100226- **#define : BL2_RO_BASE**
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000227
228 Defines the base address in secure XIP memory where BL2 RO section originally
229 lives. Must be aligned on a page-size boundary. This constant is only needed
230 when BL2_IN_XIP_MEM is set to '1'.
231
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100232- **#define : BL2_RO_LIMIT**
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000233
234 Defines the maximum address in secure XIP memory that BL2's actual content
235 (i.e. excluding any data section allocated at runtime) can occupy. This
236 constant is only needed when BL2_IN_XIP_MEM is set to '1'.
237
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100238- **#define : BL2_RW_BASE**
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000239
240 Defines the base address in secure RAM where BL2's read-write data will live
241 at runtime. Must be aligned on a page-size boundary. This constant is only
242 needed when BL2_IN_XIP_MEM is set to '1'.
243
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100244- **#define : BL2_RW_LIMIT**
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000245
246 Defines the maximum address in secure RAM that BL2's read-write data can
247 occupy at runtime. This constant is only needed when BL2_IN_XIP_MEM is set
248 to '1'.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100249
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100250- **#define : BL31_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100251
252 Defines the base address in secure RAM where BL2 loads the BL31 binary
253 image. Must be aligned on a page-size boundary.
254
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100255- **#define : BL31_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100256
257 Defines the maximum address in secure RAM that the BL31 image can occupy.
258
Tamas Ban1d3354e2022-09-16 14:09:30 +0200259- **#define : PLAT_RSS_COMMS_PAYLOAD_MAX_SIZE**
260
261 Defines the maximum message size between AP and RSS. Need to define if
262 platform supports RSS.
263
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100264For every image, the platform must define individual identifiers that will be
265used by BL1 or BL2 to load the corresponding image into memory from non-volatile
266storage. For the sake of performance, integer numbers will be used as
267identifiers. The platform will use those identifiers to return the relevant
268information about the image to be loaded (file handler, load address,
269authentication information, etc.). The following image identifiers are
270mandatory:
271
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100272- **#define : BL2_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100273
274 BL2 image identifier, used by BL1 to load BL2.
275
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100276- **#define : BL31_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100277
278 BL31 image identifier, used by BL2 to load BL31.
279
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100280- **#define : BL33_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100281
282 BL33 image identifier, used by BL2 to load BL33.
283
284If Trusted Board Boot is enabled, the following certificate identifiers must
285also be defined:
286
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100287- **#define : TRUSTED_BOOT_FW_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100288
289 BL2 content certificate identifier, used by BL1 to load the BL2 content
290 certificate.
291
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100292- **#define : TRUSTED_KEY_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100293
294 Trusted key certificate identifier, used by BL2 to load the trusted key
295 certificate.
296
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100297- **#define : SOC_FW_KEY_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100298
299 BL31 key certificate identifier, used by BL2 to load the BL31 key
300 certificate.
301
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100302- **#define : SOC_FW_CONTENT_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100303
304 BL31 content certificate identifier, used by BL2 to load the BL31 content
305 certificate.
306
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100307- **#define : NON_TRUSTED_FW_KEY_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100308
309 BL33 key certificate identifier, used by BL2 to load the BL33 key
310 certificate.
311
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100312- **#define : NON_TRUSTED_FW_CONTENT_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100313
314 BL33 content certificate identifier, used by BL2 to load the BL33 content
315 certificate.
316
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100317- **#define : FWU_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100318
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100319 Firmware Update (FWU) certificate identifier, used by NS_BL1U to load the
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100320 FWU content certificate.
321
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100322- **#define : PLAT_CRYPTOCELL_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100323
Dan Handley610e7e12018-03-01 18:44:00 +0000324 This defines the base address of Arm® TrustZone® CryptoCell and must be
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100325 defined if CryptoCell crypto driver is used for Trusted Board Boot. For
Dan Handley610e7e12018-03-01 18:44:00 +0000326 capable Arm platforms, this driver is used if ``ARM_CRYPTOCELL_INTEG`` is
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100327 set.
328
329If the AP Firmware Updater Configuration image, BL2U is used, the following
330must also be defined:
331
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100332- **#define : BL2U_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100333
334 Defines the base address in secure memory where BL1 copies the BL2U binary
335 image. Must be aligned on a page-size boundary.
336
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100337- **#define : BL2U_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100338
339 Defines the maximum address in secure memory that the BL2U image can occupy.
340
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100341- **#define : BL2U_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100342
343 BL2U image identifier, used by BL1 to fetch an image descriptor
344 corresponding to BL2U.
345
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100346If the SCP Firmware Update Configuration Image, SCP_BL2U is used, the following
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100347must also be defined:
348
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100349- **#define : SCP_BL2U_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100350
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100351 SCP_BL2U image identifier, used by BL1 to fetch an image descriptor
352 corresponding to SCP_BL2U.
Paul Beesleyba3ed402019-03-13 16:20:44 +0000353
354 .. note::
355 TF-A does not provide source code for this image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100356
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100357If the Non-Secure Firmware Updater ROM, NS_BL1U is used, the following must
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100358also be defined:
359
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100360- **#define : NS_BL1U_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100361
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100362 Defines the base address in non-secure ROM where NS_BL1U executes.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100363 Must be aligned on a page-size boundary.
Paul Beesleyba3ed402019-03-13 16:20:44 +0000364
365 .. note::
366 TF-A does not provide source code for this image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100367
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100368- **#define : NS_BL1U_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100369
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100370 NS_BL1U image identifier, used by BL1 to fetch an image descriptor
371 corresponding to NS_BL1U.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100372
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100373If the Non-Secure Firmware Updater, NS_BL2U is used, the following must also
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100374be defined:
375
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100376- **#define : NS_BL2U_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100377
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100378 Defines the base address in non-secure memory where NS_BL2U executes.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100379 Must be aligned on a page-size boundary.
Paul Beesleyba3ed402019-03-13 16:20:44 +0000380
381 .. note::
382 TF-A does not provide source code for this image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100383
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100384- **#define : NS_BL2U_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100385
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100386 NS_BL2U image identifier, used by BL1 to fetch an image descriptor
387 corresponding to NS_BL2U.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100388
389For the the Firmware update capability of TRUSTED BOARD BOOT, the following
390macros may also be defined:
391
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100392- **#define : PLAT_FWU_MAX_SIMULTANEOUS_IMAGES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100393
394 Total number of images that can be loaded simultaneously. If the platform
395 doesn't specify any value, it defaults to 10.
396
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100397If a SCP_BL2 image is supported by the platform, the following constants must
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100398also be defined:
399
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100400- **#define : SCP_BL2_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100401
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100402 SCP_BL2 image identifier, used by BL2 to load SCP_BL2 into secure memory
Paul Beesley1fbc97b2019-01-11 18:26:51 +0000403 from platform storage before being transferred to the SCP.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100404
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100405- **#define : SCP_FW_KEY_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100406
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100407 SCP_BL2 key certificate identifier, used by BL2 to load the SCP_BL2 key
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100408 certificate (mandatory when Trusted Board Boot is enabled).
409
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100410- **#define : SCP_FW_CONTENT_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100411
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100412 SCP_BL2 content certificate identifier, used by BL2 to load the SCP_BL2
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100413 content certificate (mandatory when Trusted Board Boot is enabled).
414
415If a BL32 image is supported by the platform, the following constants must
416also be defined:
417
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100418- **#define : BL32_IMAGE_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100419
420 BL32 image identifier, used by BL2 to load BL32.
421
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100422- **#define : TRUSTED_OS_FW_KEY_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100423
424 BL32 key certificate identifier, used by BL2 to load the BL32 key
425 certificate (mandatory when Trusted Board Boot is enabled).
426
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100427- **#define : TRUSTED_OS_FW_CONTENT_CERT_ID**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100428
429 BL32 content certificate identifier, used by BL2 to load the BL32 content
430 certificate (mandatory when Trusted Board Boot is enabled).
431
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100432- **#define : BL32_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100433
434 Defines the base address in secure memory where BL2 loads the BL32 binary
435 image. Must be aligned on a page-size boundary.
436
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100437- **#define : BL32_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100438
439 Defines the maximum address that the BL32 image can occupy.
440
441If the Test Secure-EL1 Payload (TSP) instantiation of BL32 is supported by the
442platform, the following constants must also be defined:
443
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100444- **#define : TSP_SEC_MEM_BASE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100445
446 Defines the base address of the secure memory used by the TSP image on the
447 platform. This must be at the same address or below ``BL32_BASE``.
448
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100449- **#define : TSP_SEC_MEM_SIZE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100450
451 Defines the size of the secure memory used by the BL32 image on the
Paul Beesley1fbc97b2019-01-11 18:26:51 +0000452 platform. ``TSP_SEC_MEM_BASE`` and ``TSP_SEC_MEM_SIZE`` must fully
453 accommodate the memory required by the BL32 image, defined by ``BL32_BASE``
454 and ``BL32_LIMIT``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100455
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100456- **#define : TSP_IRQ_SEC_PHY_TIMER**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100457
458 Defines the ID of the secure physical generic timer interrupt used by the
459 TSP's interrupt handling code.
460
461If the platform port uses the translation table library code, the following
462constants must also be defined:
463
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100464- **#define : PLAT_XLAT_TABLES_DYNAMIC**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100465
466 Optional flag that can be set per-image to enable the dynamic allocation of
467 regions even when the MMU is enabled. If not defined, only static
468 functionality will be available, if defined and set to 1 it will also
469 include the dynamic functionality.
470
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100471- **#define : MAX_XLAT_TABLES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100472
473 Defines the maximum number of translation tables that are allocated by the
474 translation table library code. To minimize the amount of runtime memory
475 used, choose the smallest value needed to map the required virtual addresses
476 for each BL stage. If ``PLAT_XLAT_TABLES_DYNAMIC`` flag is enabled for a BL
477 image, ``MAX_XLAT_TABLES`` must be defined to accommodate the dynamic regions
478 as well.
479
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100480- **#define : MAX_MMAP_REGIONS**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100481
482 Defines the maximum number of regions that are allocated by the translation
483 table library code. A region consists of physical base address, virtual base
484 address, size and attributes (Device/Memory, RO/RW, Secure/Non-Secure), as
485 defined in the ``mmap_region_t`` structure. The platform defines the regions
486 that should be mapped. Then, the translation table library will create the
487 corresponding tables and descriptors at runtime. To minimize the amount of
488 runtime memory used, choose the smallest value needed to register the
489 required regions for each BL stage. If ``PLAT_XLAT_TABLES_DYNAMIC`` flag is
490 enabled for a BL image, ``MAX_MMAP_REGIONS`` must be defined to accommodate
491 the dynamic regions as well.
492
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100493- **#define : PLAT_VIRT_ADDR_SPACE_SIZE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100494
495 Defines the total size of the virtual address space in bytes. For example,
David Cunadoc1503122018-02-16 21:12:58 +0000496 for a 32 bit virtual address space, this value should be ``(1ULL << 32)``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100497
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100498- **#define : PLAT_PHY_ADDR_SPACE_SIZE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100499
500 Defines the total size of the physical address space in bytes. For example,
David Cunadoc1503122018-02-16 21:12:58 +0000501 for a 32 bit physical address space, this value should be ``(1ULL << 32)``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100502
503If the platform port uses the IO storage framework, the following constants
504must also be defined:
505
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100506- **#define : MAX_IO_DEVICES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100507
508 Defines the maximum number of registered IO devices. Attempting to register
509 more devices than this value using ``io_register_device()`` will fail with
510 -ENOMEM.
511
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100512- **#define : MAX_IO_HANDLES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100513
514 Defines the maximum number of open IO handles. Attempting to open more IO
515 entities than this value using ``io_open()`` will fail with -ENOMEM.
516
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100517- **#define : MAX_IO_BLOCK_DEVICES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100518
519 Defines the maximum number of registered IO block devices. Attempting to
520 register more devices this value using ``io_dev_open()`` will fail
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100521 with -ENOMEM. MAX_IO_BLOCK_DEVICES should be less than MAX_IO_DEVICES.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100522 With this macro, multiple block devices could be supported at the same
523 time.
524
525If the platform needs to allocate data within the per-cpu data framework in
526BL31, it should define the following macro. Currently this is only required if
527the platform decides not to use the coherent memory section by undefining the
528``USE_COHERENT_MEM`` build flag. In this case, the framework allocates the
529required memory within the the per-cpu data to minimize wastage.
530
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100531- **#define : PLAT_PCPU_DATA_SIZE**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100532
533 Defines the memory (in bytes) to be reserved within the per-cpu data
534 structure for use by the platform layer.
535
536The following constants are optional. They should be defined when the platform
Dan Handley610e7e12018-03-01 18:44:00 +0000537memory layout implies some image overlaying like in Arm standard platforms.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100538
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100539- **#define : BL31_PROGBITS_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100540
541 Defines the maximum address in secure RAM that the BL31's progbits sections
542 can occupy.
543
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100544- **#define : TSP_PROGBITS_LIMIT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100545
546 Defines the maximum address that the TSP's progbits sections can occupy.
547
Wing Li2c556f32022-09-14 13:18:17 -0700548If the platform supports OS-initiated mode, i.e. the build option
549``PSCI_OS_INIT_MODE`` is enabled, and if the platform's maximum power domain
550level for PSCI_CPU_SUSPEND differs from ``PLAT_MAX_PWR_LVL``, the following
551constant must be defined.
552
553- **#define : PLAT_MAX_CPU_SUSPEND_PWR_LVL**
554
555 Defines the maximum power domain level that PSCI_CPU_SUSPEND should apply to.
556
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100557If the platform port uses the PL061 GPIO driver, the following constant may
558optionally be defined:
559
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100560- **PLAT_PL061_MAX_GPIOS**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100561 Maximum number of GPIOs required by the platform. This allows control how
562 much memory is allocated for PL061 GPIO controllers. The default value is
563
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100564 #. $(eval $(call add_define,PLAT_PL061_MAX_GPIOS))
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100565
566If the platform port uses the partition driver, the following constant may
567optionally be defined:
568
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100569- **PLAT_PARTITION_MAX_ENTRIES**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100570 Maximum number of partition entries required by the platform. This allows
571 control how much memory is allocated for partition entries. The default
572 value is 128.
Paul Beesleyf8640672019-04-12 14:19:42 +0100573 For example, define the build flag in ``platform.mk``:
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100574 PLAT_PARTITION_MAX_ENTRIES := 12
575 $(eval $(call add_define,PLAT_PARTITION_MAX_ENTRIES))
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100576
Haojian Zhuang42a746d2019-09-14 18:01:16 +0800577- **PLAT_PARTITION_BLOCK_SIZE**
578 The size of partition block. It could be either 512 bytes or 4096 bytes.
579 The default value is 512.
Paul Beesleyf2ec7142019-10-04 16:17:46 +0000580 For example, define the build flag in ``platform.mk``:
Haojian Zhuang42a746d2019-09-14 18:01:16 +0800581 PLAT_PARTITION_BLOCK_SIZE := 4096
582 $(eval $(call add_define,PLAT_PARTITION_BLOCK_SIZE))
583
Rob Hughes7a354bd2023-02-20 12:03:52 +0000584If the platform port uses the Arm® Ethos™-N NPU driver, the following
585configuration must be performed:
586
587- The NPU SiP service handler must be hooked up. This consists of both the
588 initial setup (``ethosn_smc_setup``) and the handler itself
589 (``ethosn_smc_handler``)
590
Rajasekaran Kalidossf8a18b82022-11-16 17:16:44 +0100591If the platform port uses the Arm® Ethos™-N NPU driver with TZMP1 support
Rob Hughes7a354bd2023-02-20 12:03:52 +0000592enabled, the following constants and configuration must also be defined:
Rajasekaran Kalidossf8a18b82022-11-16 17:16:44 +0100593
594- **ARM_ETHOSN_NPU_PROT_FW_NSAID**
595
596 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use to
597 access the protected memory that contains the NPU's firmware.
598
Mikael Olsson80b61f52023-03-14 18:29:06 +0100599- **ARM_ETHOSN_NPU_PROT_DATA_RW_NSAID**
600
601 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for
602 read/write access to the protected memory that contains inference data.
603
604- **ARM_ETHOSN_NPU_PROT_DATA_RO_NSAID**
605
606 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for
607 read-only access to the protected memory that contains inference data.
608
609- **ARM_ETHOSN_NPU_NS_RW_DATA_NSAID**
610
611 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for
612 read/write access to the non-protected memory.
613
614- **ARM_ETHOSN_NPU_NS_RO_DATA_NSAID**
Rajasekaran Kalidossf8a18b82022-11-16 17:16:44 +0100615
Mikael Olsson80b61f52023-03-14 18:29:06 +0100616 Defines the Non-secure Access IDentity (NSAID) that the NPU shall use for
617 read-only access to the non-protected memory.
Rajasekaran Kalidossf8a18b82022-11-16 17:16:44 +0100618
Rob Hughes9a2177a2023-01-17 16:10:26 +0000619- **ARM_ETHOSN_NPU_FW_IMAGE_BASE** and **ARM_ETHOSN_NPU_FW_IMAGE_LIMIT**
620
Rob Hughes7a354bd2023-02-20 12:03:52 +0000621 Defines the physical address range that the NPU's firmware will be loaded
622 into and executed from.
623
624- Configure the platforms TrustZone Controller (TZC) with appropriate regions
625 of protected memory. At minimum this must include a region for the NPU's
626 firmware code and a region for protected inference data, and these must be
627 accessible using the NSAIDs defined above.
628
629- Include the NPU firmware and certificates in the FIP.
630
631- Provide FCONF entries to configure the image source for the NPU firmware
632 and certificates.
Rob Hughes9a2177a2023-01-17 16:10:26 +0000633
634- Add MMU mappings such that:
635
636 - BL2 can write the NPU firmware into the region defined by
637 ``ARM_ETHOSN_NPU_FW_IMAGE_BASE`` and ``ARM_ETHOSN_NPU_FW_IMAGE_LIMIT``
638 - BL31 (SiP service) can read the NPU firmware from the same region
639
Rob Hughes7a354bd2023-02-20 12:03:52 +0000640- Add the firmware image ID ``ARM_ETHOSN_NPU_FW_IMAGE_ID`` to the list of images
641 loaded by BL2.
Rob Hughes9a2177a2023-01-17 16:10:26 +0000642
643Please see the reference implementation code for the Juno platform as an example.
644
645
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100646The following constant is optional. It should be defined to override the default
647behaviour of the ``assert()`` function (for example, to save memory).
648
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100649- **PLAT_LOG_LEVEL_ASSERT**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100650 If ``PLAT_LOG_LEVEL_ASSERT`` is higher or equal than ``LOG_LEVEL_VERBOSE``,
651 ``assert()`` prints the name of the file, the line number and the asserted
652 expression. Else if it is higher than ``LOG_LEVEL_INFO``, it prints the file
653 name and the line number. Else if it is lower than ``LOG_LEVEL_INFO``, it
654 doesn't print anything to the console. If ``PLAT_LOG_LEVEL_ASSERT`` isn't
655 defined, it defaults to ``LOG_LEVEL``.
656
Lucian Paul-Trifub93037a2022-06-22 18:45:36 +0100657If the platform port uses the DRTM feature, the following constants must be
658defined:
659
660- **#define : PLAT_DRTM_EVENT_LOG_MAX_SIZE**
661
662 Maximum Event Log size used by the platform. Platform can decide the maximum
663 size of the Event Log buffer, depending upon the highest hash algorithm
664 chosen and the number of components selected to measure during the DRTM
665 execution flow.
666
667- **#define : PLAT_DRTM_MMAP_ENTRIES**
668
669 Number of the MMAP entries used by the DRTM implementation to calculate the
670 size of address map region of the platform.
671
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100672File : plat_macros.S [mandatory]
673~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100674
675Each platform must ensure a file of this name is in the system include path with
Dan Handley610e7e12018-03-01 18:44:00 +0000676the following macro defined. In the Arm development platforms, this file is
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100677found in ``plat/arm/board/<plat_name>/include/plat_macros.S``.
678
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100679- **Macro : plat_crash_print_regs**
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100680
681 This macro allows the crash reporting routine to print relevant platform
682 registers in case of an unhandled exception in BL31. This aids in debugging
683 and this macro can be defined to be empty in case register reporting is not
684 desired.
685
686 For instance, GIC or interconnect registers may be helpful for
687 troubleshooting.
688
689Handling Reset
690--------------
691
692BL1 by default implements the reset vector where execution starts from a cold
693or warm boot. BL31 can be optionally set as a reset vector using the
694``RESET_TO_BL31`` make variable.
695
696For each CPU, the reset vector code is responsible for the following tasks:
697
698#. Distinguishing between a cold boot and a warm boot.
699
700#. In the case of a cold boot and the CPU being a secondary CPU, ensuring that
701 the CPU is placed in a platform-specific state until the primary CPU
702 performs the necessary steps to remove it from this state.
703
704#. In the case of a warm boot, ensuring that the CPU jumps to a platform-
705 specific address in the BL31 image in the same processor mode as it was
706 when released from reset.
707
708The following functions need to be implemented by the platform port to enable
709reset vector code to perform the above tasks.
710
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100711Function : plat_get_my_entrypoint() [mandatory when PROGRAMMABLE_RESET_ADDRESS == 0]
712~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100713
714::
715
716 Argument : void
717 Return : uintptr_t
718
719This function is called with the MMU and caches disabled
720(``SCTLR_EL3.M`` = 0 and ``SCTLR_EL3.C`` = 0). The function is responsible for
721distinguishing between a warm and cold reset for the current CPU using
722platform-specific means. If it's a warm reset, then it returns the warm
723reset entrypoint point provided to ``plat_setup_psci_ops()`` during
724BL31 initialization. If it's a cold reset then this function must return zero.
725
726This function does not follow the Procedure Call Standard used by the
Dan Handley610e7e12018-03-01 18:44:00 +0000727Application Binary Interface for the Arm 64-bit architecture. The caller should
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100728not assume that callee saved registers are preserved across a call to this
729function.
730
731This function fulfills requirement 1 and 3 listed above.
732
733Note that for platforms that support programming the reset address, it is
734expected that a CPU will start executing code directly at the right address,
735both on a cold and warm reset. In this case, there is no need to identify the
736type of reset nor to query the warm reset entrypoint. Therefore, implementing
737this function is not required on such platforms.
738
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100739Function : plat_secondary_cold_boot_setup() [mandatory when COLD_BOOT_SINGLE_CPU == 0]
740~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100741
742::
743
744 Argument : void
745
746This function is called with the MMU and data caches disabled. It is responsible
747for placing the executing secondary CPU in a platform-specific state until the
748primary CPU performs the necessary actions to bring it out of that state and
749allow entry into the OS. This function must not return.
750
Dan Handley610e7e12018-03-01 18:44:00 +0000751In the Arm FVP port, when using the normal boot flow, each secondary CPU powers
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100752itself off. The primary CPU is responsible for powering up the secondary CPUs
753when normal world software requires them. When booting an EL3 payload instead,
754they stay powered on and are put in a holding pen until their mailbox gets
755populated.
756
757This function fulfills requirement 2 above.
758
759Note that for platforms that can't release secondary CPUs out of reset, only the
760primary CPU will execute the cold boot code. Therefore, implementing this
761function is not required on such platforms.
762
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100763Function : plat_is_my_cpu_primary() [mandatory when COLD_BOOT_SINGLE_CPU == 0]
764~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100765
766::
767
768 Argument : void
769 Return : unsigned int
770
771This function identifies whether the current CPU is the primary CPU or a
772secondary CPU. A return value of zero indicates that the CPU is not the
773primary CPU, while a non-zero return value indicates that the CPU is the
774primary CPU.
775
776Note that for platforms that can't release secondary CPUs out of reset, only the
777primary CPU will execute the cold boot code. Therefore, there is no need to
778distinguish between primary and secondary CPUs and implementing this function is
779not required.
780
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100781Function : platform_mem_init() [mandatory]
782~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100783
784::
785
786 Argument : void
787 Return : void
788
789This function is called before any access to data is made by the firmware, in
790order to carry out any essential memory initialization.
791
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100792Function: plat_get_rotpk_info()
793~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100794
795::
796
797 Argument : void *, void **, unsigned int *, unsigned int *
798 Return : int
799
800This function is mandatory when Trusted Board Boot is enabled. It returns a
801pointer to the ROTPK stored in the platform (or a hash of it) and its length.
802The ROTPK must be encoded in DER format according to the following ASN.1
803structure:
804
805::
806
807 AlgorithmIdentifier ::= SEQUENCE {
808 algorithm OBJECT IDENTIFIER,
809 parameters ANY DEFINED BY algorithm OPTIONAL
810 }
811
812 SubjectPublicKeyInfo ::= SEQUENCE {
813 algorithm AlgorithmIdentifier,
814 subjectPublicKey BIT STRING
815 }
816
817In case the function returns a hash of the key:
818
819::
820
821 DigestInfo ::= SEQUENCE {
822 digestAlgorithm AlgorithmIdentifier,
823 digest OCTET STRING
824 }
825
826The function returns 0 on success. Any other value is treated as error by the
827Trusted Board Boot. The function also reports extra information related
828to the ROTPK in the flags parameter:
829
830::
831
832 ROTPK_IS_HASH : Indicates that the ROTPK returned by the platform is a
833 hash.
834 ROTPK_NOT_DEPLOYED : This allows the platform to skip certificate ROTPK
835 verification while the platform ROTPK is not deployed.
836 When this flag is set, the function does not need to
837 return a platform ROTPK, and the authentication
838 framework uses the ROTPK in the certificate without
839 verifying it against the platform value. This flag
840 must not be used in a deployed production environment.
841
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100842Function: plat_get_nv_ctr()
843~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100844
845::
846
847 Argument : void *, unsigned int *
848 Return : int
849
850This function is mandatory when Trusted Board Boot is enabled. It returns the
851non-volatile counter value stored in the platform in the second argument. The
852cookie in the first argument may be used to select the counter in case the
853platform provides more than one (for example, on platforms that use the default
854TBBR CoT, the cookie will correspond to the OID values defined in
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100855TRUSTED_FW_NVCOUNTER_OID or NON_TRUSTED_FW_NVCOUNTER_OID).
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100856
857The function returns 0 on success. Any other value means the counter value could
858not be retrieved from the platform.
859
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100860Function: plat_set_nv_ctr()
861~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100862
863::
864
865 Argument : void *, unsigned int
866 Return : int
867
868This function is mandatory when Trusted Board Boot is enabled. It sets a new
869counter value in the platform. The cookie in the first argument may be used to
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100870select the counter (as explained in plat_get_nv_ctr()). The second argument is
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100871the updated counter value to be written to the NV counter.
872
873The function returns 0 on success. Any other value means the counter value could
874not be updated.
875
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +0100876Function: plat_set_nv_ctr2()
877~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100878
879::
880
881 Argument : void *, const auth_img_desc_t *, unsigned int
882 Return : int
883
884This function is optional when Trusted Board Boot is enabled. If this
885interface is defined, then ``plat_set_nv_ctr()`` need not be defined. The
886first argument passed is a cookie and is typically used to
887differentiate between a Non Trusted NV Counter and a Trusted NV
888Counter. The second argument is a pointer to an authentication image
889descriptor and may be used to decide if the counter is allowed to be
890updated or not. The third argument is the updated counter value to
891be written to the NV counter.
892
893The function returns 0 on success. Any other value means the counter value
894either could not be updated or the authentication image descriptor indicates
895that it is not allowed to be updated.
896
Lucian Paul-Trifub93037a2022-06-22 18:45:36 +0100897Dynamic Root of Trust for Measurement support (in BL31)
898-------------------------------------------------------
899
900The functions mentioned in this section are mandatory, when platform enables
901DRTM_SUPPORT build flag.
902
903Function : plat_get_addr_mmap()
904~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
905
906::
907
908 Argument : void
909 Return : const mmap_region_t *
910
911This function is used to return the address of the platform *address-map* table,
912which describes the regions of normal memory, memory mapped I/O
913and non-volatile memory.
914
915Function : plat_has_non_host_platforms()
916~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
917
918::
919
920 Argument : void
921 Return : bool
922
923This function returns *true* if the platform has any trusted devices capable of
924DMA, otherwise returns *false*.
925
926Function : plat_has_unmanaged_dma_peripherals()
927~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
928
929::
930
931 Argument : void
932 Return : bool
933
934This function returns *true* if platform uses peripherals whose DMA is not
935managed by an SMMU, otherwise returns *false*.
936
937Note -
938If the platform has peripherals that are not managed by the SMMU, then the
939platform should investigate such peripherals to determine whether they can
940be trusted, and such peripherals should be moved under "Non-host platforms"
941if they can be trusted.
942
943Function : plat_get_total_num_smmus()
944~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
945
946::
947
948 Argument : void
949 Return : unsigned int
950
951This function returns the total number of SMMUs in the platform.
952
953Function : plat_enumerate_smmus()
954~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
955::
956
957
958 Argument : void
959 Return : const uintptr_t *, size_t
960
961This function returns an array of SMMU addresses and the actual number of SMMUs
962reported by the platform.
963
964Function : plat_drtm_get_dma_prot_features()
965~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
966
967::
968
969 Argument : void
970 Return : const plat_drtm_dma_prot_features_t*
971
972This function returns the address of plat_drtm_dma_prot_features_t structure
973containing the maximum number of protected regions and bitmap with the types
974of DMA protection supported by the platform.
975For more details see section 3.3 Table 6 of `DRTM`_ specification.
976
977Function : plat_drtm_dma_prot_get_max_table_bytes()
978~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
979
980::
981
982 Argument : void
983 Return : uint64_t
984
985This function returns the maximum size of DMA protected regions table in
986bytes.
987
988Function : plat_drtm_get_tpm_features()
989~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
990
991::
992
993 Argument : void
994 Return : const plat_drtm_tpm_features_t*
995
996This function returns the address of *plat_drtm_tpm_features_t* structure
997containing PCR usage schema, TPM-based hash, and firmware hash algorithm
998supported by the platform.
999
1000Function : plat_drtm_get_min_size_normal_world_dce()
1001~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1002
1003::
1004
1005 Argument : void
1006 Return : uint64_t
1007
1008This function returns the size normal-world DCE of the platform.
1009
1010Function : plat_drtm_get_imp_def_dlme_region_size()
1011~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1012
1013::
1014
1015 Argument : void
1016 Return : uint64_t
1017
1018This function returns the size of implementation defined DLME region
1019of the platform.
1020
1021Function : plat_drtm_get_tcb_hash_table_size()
1022~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1023
1024::
1025
1026 Argument : void
1027 Return : uint64_t
1028
1029This function returns the size of TCB hash table of the platform.
1030
1031Function : plat_drtm_get_tcb_hash_features()
1032~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1033
1034::
1035
1036 Argument : void
1037 Return : uint64_t
1038
1039This function returns the Maximum number of TCB hashes recorded by the
1040platform.
1041For more details see section 3.3 Table 6 of `DRTM`_ specification.
1042
1043Function : plat_drtm_validate_ns_region()
1044~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1045
1046::
1047
1048 Argument : uintptr_t, uintptr_t
1049 Return : int
1050
1051This function validates that given region is within the Non-Secure region
1052of DRAM. This function takes a region start address and size an input
1053arguments, and returns 0 on success and -1 on failure.
1054
1055Function : plat_set_drtm_error()
1056~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1057
1058::
1059
1060 Argument : uint64_t
1061 Return : int
1062
1063This function writes a 64 bit error code received as input into
1064non-volatile storage and returns 0 on success and -1 on failure.
1065
1066Function : plat_get_drtm_error()
1067~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1068
1069::
1070
1071 Argument : uint64_t*
1072 Return : int
1073
1074This function reads a 64 bit error code from the non-volatile storage
1075into the received address, and returns 0 on success and -1 on failure.
1076
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001077Common mandatory function modifications
1078---------------------------------------
1079
1080The following functions are mandatory functions which need to be implemented
1081by the platform port.
1082
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001083Function : plat_my_core_pos()
1084~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001085
1086::
1087
1088 Argument : void
1089 Return : unsigned int
1090
Paul Beesley1fbc97b2019-01-11 18:26:51 +00001091This function returns the index of the calling CPU which is used as a
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001092CPU-specific linear index into blocks of memory (for example while allocating
1093per-CPU stacks). This function will be invoked very early in the
1094initialization sequence which mandates that this function should be
Paul Beesley1fbc97b2019-01-11 18:26:51 +00001095implemented in assembly and should not rely on the availability of a C
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001096runtime environment. This function can clobber x0 - x8 and must preserve
1097x9 - x29.
1098
1099This function plays a crucial role in the power domain topology framework in
Paul Beesleyf8640672019-04-12 14:19:42 +01001100PSCI and details of this can be found in
1101:ref:`PSCI Power Domain Tree Structure`.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001102
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001103Function : plat_core_pos_by_mpidr()
1104~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001105
1106::
1107
1108 Argument : u_register_t
1109 Return : int
1110
1111This function validates the ``MPIDR`` of a CPU and converts it to an index,
1112which can be used as a CPU-specific linear index into blocks of memory. In
1113case the ``MPIDR`` is invalid, this function returns -1. This function will only
1114be invoked by BL31 after the power domain topology is initialized and can
Dan Handley610e7e12018-03-01 18:44:00 +00001115utilize the C runtime environment. For further details about how TF-A
1116represents the power domain topology and how this relates to the linear CPU
Paul Beesleyf8640672019-04-12 14:19:42 +01001117index, please refer :ref:`PSCI Power Domain Tree Structure`.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001118
Ambroise Vincentd207f562019-04-10 12:50:27 +01001119Function : plat_get_mbedtls_heap() [when TRUSTED_BOARD_BOOT == 1]
1120~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1121
1122::
1123
1124 Arguments : void **heap_addr, size_t *heap_size
1125 Return : int
1126
1127This function is invoked during Mbed TLS library initialisation to get a heap,
1128by means of a starting address and a size. This heap will then be used
1129internally by the Mbed TLS library. Hence, each BL stage that utilises Mbed TLS
1130must be able to provide a heap to it.
1131
1132A helper function can be found in `drivers/auth/mbedtls/mbedtls_common.c` in
1133which a heap is statically reserved during compile time inside every image
1134(i.e. every BL stage) that utilises Mbed TLS. In this default implementation,
1135the function simply returns the address and size of this "pre-allocated" heap.
1136For a platform to use this default implementation, only a call to the helper
1137from inside plat_get_mbedtls_heap() body is enough and nothing else is needed.
1138
1139However, by writting their own implementation, platforms have the potential to
1140optimise memory usage. For example, on some Arm platforms, the Mbed TLS heap is
1141shared between BL1 and BL2 stages and, thus, the necessary space is not reserved
1142twice.
1143
1144On success the function should return 0 and a negative error code otherwise.
1145
Sumit Gargc0c369c2019-11-15 18:47:53 +05301146Function : plat_get_enc_key_info() [when FW_ENC_STATUS == 0 or 1]
1147~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1148
1149::
1150
1151 Arguments : enum fw_enc_status_t fw_enc_status, uint8_t *key,
1152 size_t *key_len, unsigned int *flags, const uint8_t *img_id,
1153 size_t img_id_len
1154 Return : int
1155
1156This function provides a symmetric key (either SSK or BSSK depending on
1157fw_enc_status) which is invoked during runtime decryption of encrypted
1158firmware images. `plat/common/plat_bl_common.c` provides a dummy weak
1159implementation for testing purposes which must be overridden by the platform
1160trying to implement a real world firmware encryption use-case.
1161
1162It also allows the platform to pass symmetric key identifier rather than
1163actual symmetric key which is useful in cases where the crypto backend provides
1164secure storage for the symmetric key. So in this case ``ENC_KEY_IS_IDENTIFIER``
1165flag must be set in ``flags``.
1166
1167In addition to above a platform may also choose to provide an image specific
1168symmetric key/identifier using img_id.
1169
1170On success the function should return 0 and a negative error code otherwise.
1171
Manish Pandey34a305e2021-10-21 21:53:49 +01001172Note that this API depends on ``DECRYPTION_SUPPORT`` build flag.
Sumit Gargc0c369c2019-11-15 18:47:53 +05301173
Manish V Badarkheda87af12021-06-20 21:14:46 +01001174Function : plat_fwu_set_images_source() [when PSA_FWU_SUPPORT == 1]
1175~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1176
1177::
1178
Sughosh Ganuf40154f2021-11-17 17:08:10 +05301179 Argument : const struct fwu_metadata *metadata
Manish V Badarkheda87af12021-06-20 21:14:46 +01001180 Return : void
1181
1182This function is mandatory when PSA_FWU_SUPPORT is enabled.
1183It provides a means to retrieve image specification (offset in
1184non-volatile storage and length) of active/updated images using the passed
1185FWU metadata, and update I/O policies of active/updated images using retrieved
1186image specification information.
1187Further I/O layer operations such as I/O open, I/O read, etc. on these
1188images rely on this function call.
1189
1190In Arm platforms, this function is used to set an I/O policy of the FIP image,
1191container of all active/updated secure and non-secure images.
1192
1193Function : plat_fwu_set_metadata_image_source() [when PSA_FWU_SUPPORT == 1]
1194~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1195
1196::
1197
1198 Argument : unsigned int image_id, uintptr_t *dev_handle,
1199 uintptr_t *image_spec
1200 Return : int
1201
1202This function is mandatory when PSA_FWU_SUPPORT is enabled. It is
1203responsible for setting up the platform I/O policy of the requested metadata
1204image (either FWU_METADATA_IMAGE_ID or BKUP_FWU_METADATA_IMAGE_ID) that will
1205be used to load this image from the platform's non-volatile storage.
1206
1207FWU metadata can not be always stored as a raw image in non-volatile storage
1208to define its image specification (offset in non-volatile storage and length)
1209statically in I/O policy.
1210For example, the FWU metadata image is stored as a partition inside the GUID
1211partition table image. Its specification is defined in the partition table
1212that needs to be parsed dynamically.
1213This function provides a means to retrieve such dynamic information to set
1214the I/O policy of the FWU metadata image.
1215Further I/O layer operations such as I/O open, I/O read, etc. on FWU metadata
1216image relies on this function call.
1217
1218It returns '0' on success, otherwise a negative error value on error.
1219Alongside, returns device handle and image specification from the I/O policy
1220of the requested FWU metadata image.
1221
Sughosh Ganu4e336a62021-12-01 15:53:32 +05301222Function : plat_fwu_get_boot_idx() [when PSA_FWU_SUPPORT == 1]
1223~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1224
1225::
1226
1227 Argument : void
1228 Return : uint32_t
1229
1230This function is mandatory when PSA_FWU_SUPPORT is enabled. It provides the
1231means to retrieve the boot index value from the platform. The boot index is the
1232bank from which the platform has booted the firmware images.
1233
1234By default, the platform will read the metadata structure and try to boot from
1235the active bank. If the platform fails to boot from the active bank due to
1236reasons like an Authentication failure, or on crossing a set number of watchdog
1237resets while booting from the active bank, the platform can then switch to boot
1238from a different bank. This function then returns the bank that the platform
1239should boot its images from.
1240
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001241Common optional modifications
1242-----------------------------
1243
1244The following are helper functions implemented by the firmware that perform
1245common platform-specific tasks. A platform may choose to override these
1246definitions.
1247
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001248Function : plat_set_my_stack()
1249~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001250
1251::
1252
1253 Argument : void
1254 Return : void
1255
1256This function sets the current stack pointer to the normal memory stack that
1257has been allocated for the current CPU. For BL images that only require a
1258stack for the primary CPU, the UP version of the function is used. The size
1259of the stack allocated to each CPU is specified by the platform defined
1260constant ``PLATFORM_STACK_SIZE``.
1261
1262Common implementations of this function for the UP and MP BL images are
Paul Beesleyf8640672019-04-12 14:19:42 +01001263provided in ``plat/common/aarch64/platform_up_stack.S`` and
1264``plat/common/aarch64/platform_mp_stack.S``
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001265
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001266Function : plat_get_my_stack()
1267~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001268
1269::
1270
1271 Argument : void
1272 Return : uintptr_t
1273
1274This function returns the base address of the normal memory stack that
1275has been allocated for the current CPU. For BL images that only require a
1276stack for the primary CPU, the UP version of the function is used. The size
1277of the stack allocated to each CPU is specified by the platform defined
1278constant ``PLATFORM_STACK_SIZE``.
1279
1280Common implementations of this function for the UP and MP BL images are
Paul Beesleyf8640672019-04-12 14:19:42 +01001281provided in ``plat/common/aarch64/platform_up_stack.S`` and
1282``plat/common/aarch64/platform_mp_stack.S``
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001283
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001284Function : plat_report_exception()
1285~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001286
1287::
1288
1289 Argument : unsigned int
1290 Return : void
1291
1292A platform may need to report various information about its status when an
1293exception is taken, for example the current exception level, the CPU security
1294state (secure/non-secure), the exception type, and so on. This function is
1295called in the following circumstances:
1296
1297- In BL1, whenever an exception is taken.
1298- In BL2, whenever an exception is taken.
1299
1300The default implementation doesn't do anything, to avoid making assumptions
1301about the way the platform displays its status information.
1302
1303For AArch64, this function receives the exception type as its argument.
1304Possible values for exceptions types are listed in the
Paul Beesleyf8640672019-04-12 14:19:42 +01001305``include/common/bl_common.h`` header file. Note that these constants are not
Dan Handley610e7e12018-03-01 18:44:00 +00001306related to any architectural exception code; they are just a TF-A convention.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001307
1308For AArch32, this function receives the exception mode as its argument.
1309Possible values for exception modes are listed in the
Paul Beesleyf8640672019-04-12 14:19:42 +01001310``include/lib/aarch32/arch.h`` header file.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001311
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001312Function : plat_reset_handler()
1313~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001314
1315::
1316
1317 Argument : void
1318 Return : void
1319
1320A platform may need to do additional initialization after reset. This function
Paul Beesleyf2ec7142019-10-04 16:17:46 +00001321allows the platform to do the platform specific initializations. Platform
Paul Beesley1fbc97b2019-01-11 18:26:51 +00001322specific errata workarounds could also be implemented here. The API should
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001323preserve the values of callee saved registers x19 to x29.
1324
1325The default implementation doesn't do anything. If a platform needs to override
Paul Beesleyf8640672019-04-12 14:19:42 +01001326the default implementation, refer to the :ref:`Firmware Design` for general
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001327guidelines.
1328
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001329Function : plat_disable_acp()
1330~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001331
1332::
1333
1334 Argument : void
1335 Return : void
1336
John Tsichritzis6dda9762018-07-23 09:18:04 +01001337This API allows a platform to disable the Accelerator Coherency Port (if
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001338present) during a cluster power down sequence. The default weak implementation
John Tsichritzis6dda9762018-07-23 09:18:04 +01001339doesn't do anything. Since this API is called during the power down sequence,
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001340it has restrictions for stack usage and it can use the registers x0 - x17 as
1341scratch registers. It should preserve the value in x18 register as it is used
1342by the caller to store the return address.
1343
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001344Function : plat_error_handler()
1345~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001346
1347::
1348
1349 Argument : int
1350 Return : void
1351
1352This API is called when the generic code encounters an error situation from
1353which it cannot continue. It allows the platform to perform error reporting or
1354recovery actions (for example, reset the system). This function must not return.
1355
1356The parameter indicates the type of error using standard codes from ``errno.h``.
1357Possible errors reported by the generic code are:
1358
1359- ``-EAUTH``: a certificate or image could not be authenticated (when Trusted
1360 Board Boot is enabled)
1361- ``-ENOENT``: the requested image or certificate could not be found or an IO
1362 error was detected
Dan Handley610e7e12018-03-01 18:44:00 +00001363- ``-ENOMEM``: resources exhausted. TF-A does not use dynamic memory, so this
1364 error is usually an indication of an incorrect array size
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001365
1366The default implementation simply spins.
1367
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001368Function : plat_panic_handler()
1369~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001370
1371::
1372
1373 Argument : void
1374 Return : void
1375
1376This API is called when the generic code encounters an unexpected error
1377situation from which it cannot recover. This function must not return,
1378and must be implemented in assembly because it may be called before the C
1379environment is initialized.
1380
Paul Beesleyba3ed402019-03-13 16:20:44 +00001381.. note::
1382 The address from where it was called is stored in x30 (Link Register).
1383 The default implementation simply spins.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001384
Lucian Paul-Trifub93037a2022-06-22 18:45:36 +01001385Function : plat_system_reset()
1386~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1387
1388::
1389
1390 Argument : void
1391 Return : void
1392
1393This function is used by the platform to resets the system. It can be used
1394in any specific use-case where system needs to be resetted. For example,
1395in case of DRTM implementation this function reset the system after
1396writing the DRTM error code in the non-volatile storage. This function
1397never returns. Failure in reset results in panic.
1398
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001399Function : plat_get_bl_image_load_info()
1400~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001401
1402::
1403
1404 Argument : void
1405 Return : bl_load_info_t *
1406
1407This function returns pointer to the list of images that the platform has
Soby Mathew97b1bff2018-09-27 16:46:41 +01001408populated to load. This function is invoked in BL2 to load the
1409BL3xx images.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001410
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001411Function : plat_get_next_bl_params()
1412~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001413
1414::
1415
1416 Argument : void
1417 Return : bl_params_t *
1418
1419This function returns a pointer to the shared memory that the platform has
Dan Handley610e7e12018-03-01 18:44:00 +00001420kept aside to pass TF-A related information that next BL image needs. This
Soby Mathew97b1bff2018-09-27 16:46:41 +01001421function is invoked in BL2 to pass this information to the next BL
1422image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001423
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001424Function : plat_get_stack_protector_canary()
1425~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001426
1427::
1428
1429 Argument : void
1430 Return : u_register_t
1431
1432This function returns a random value that is used to initialize the canary used
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001433when the stack protector is enabled with ENABLE_STACK_PROTECTOR. A predictable
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001434value will weaken the protection as the attacker could easily write the right
1435value as part of the attack most of the time. Therefore, it should return a
1436true random number.
1437
Paul Beesleyba3ed402019-03-13 16:20:44 +00001438.. warning::
1439 For the protection to be effective, the global data need to be placed at
1440 a lower address than the stack bases. Failure to do so would allow an
1441 attacker to overwrite the canary as part of the stack buffer overflow attack.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001442
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001443Function : plat_flush_next_bl_params()
1444~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001445
1446::
1447
1448 Argument : void
1449 Return : void
1450
1451This function flushes to main memory all the image params that are passed to
Soby Mathew97b1bff2018-09-27 16:46:41 +01001452next image. This function is invoked in BL2 to flush this information
1453to the next BL image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001454
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001455Function : plat_log_get_prefix()
1456~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Soby Mathewaaf15f52017-09-04 11:49:29 +01001457
1458::
1459
1460 Argument : unsigned int
1461 Return : const char *
1462
1463This function defines the prefix string corresponding to the `log_level` to be
Dan Handley610e7e12018-03-01 18:44:00 +00001464prepended to all the log output from TF-A. The `log_level` (argument) will
1465correspond to one of the standard log levels defined in debug.h. The platform
1466can override the common implementation to define a different prefix string for
John Tsichritzis30f89642018-06-07 16:31:34 +01001467the log output. The implementation should be robust to future changes that
Dan Handley610e7e12018-03-01 18:44:00 +00001468increase the number of log levels.
Soby Mathewaaf15f52017-09-04 11:49:29 +01001469
Manish V Badarkhef809c6e2020-02-22 08:43:00 +00001470Function : plat_get_soc_version()
Manish V Badarkhe904f93a2020-03-26 14:20:27 +00001471~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Manish V Badarkhef809c6e2020-02-22 08:43:00 +00001472
1473::
1474
1475 Argument : void
1476 Return : int32_t
1477
1478This function returns soc version which mainly consist of below fields
1479
1480::
1481
1482 soc_version[30:24] = JEP-106 continuation code for the SiP
1483 soc_version[23:16] = JEP-106 identification code with parity bit for the SiP
Manish V Badarkhe80f13ee2020-07-23 20:23:01 +01001484 soc_version[15:0] = Implementation defined SoC ID
Manish V Badarkhef809c6e2020-02-22 08:43:00 +00001485
1486Function : plat_get_soc_revision()
Manish V Badarkhe904f93a2020-03-26 14:20:27 +00001487~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Manish V Badarkhef809c6e2020-02-22 08:43:00 +00001488
1489::
1490
1491 Argument : void
1492 Return : int32_t
1493
1494This function returns soc revision in below format
1495
1496::
1497
1498 soc_revision[0:30] = SOC revision of specific SOC
1499
Manish V Badarkhe80f13ee2020-07-23 20:23:01 +01001500Function : plat_is_smccc_feature_available()
1501~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1502
1503::
1504
1505 Argument : u_register_t
1506 Return : int32_t
1507
1508This function returns SMC_ARCH_CALL_SUCCESS if the platform supports
1509the SMCCC function specified in the argument; otherwise returns
1510SMC_ARCH_CALL_NOT_SUPPORTED.
1511
Okash Khawaja037b56e2022-11-04 12:38:01 +00001512Function : plat_can_cmo()
1513~~~~~~~~~~~~~~~~~~~~~~~~~
1514
1515::
1516
1517 Argument : void
1518 Return : uint64_t
1519
1520When CONDITIONAL_CMO flag is enabled:
1521
1522- This function indicates whether cache management operations should be
1523 performed. It returns 0 if CMOs should be skipped and non-zero
1524 otherwise.
Okash Khawaja94532202022-11-14 12:50:30 +00001525- The function must not clobber x1, x2 and x3. It's also not safe to rely on
1526 stack. Otherwise obey AAPCS.
Okash Khawaja037b56e2022-11-04 12:38:01 +00001527
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001528Modifications specific to a Boot Loader stage
1529---------------------------------------------
1530
1531Boot Loader Stage 1 (BL1)
1532-------------------------
1533
1534BL1 implements the reset vector where execution starts from after a cold or
1535warm boot. For each CPU, BL1 is responsible for the following tasks:
1536
1537#. Handling the reset as described in section 2.2
1538
1539#. In the case of a cold boot and the CPU being the primary CPU, ensuring that
1540 only this CPU executes the remaining BL1 code, including loading and passing
1541 control to the BL2 stage.
1542
1543#. Identifying and starting the Firmware Update process (if required).
1544
1545#. Loading the BL2 image from non-volatile storage into secure memory at the
1546 address specified by the platform defined constant ``BL2_BASE``.
1547
1548#. Populating a ``meminfo`` structure with the following information in memory,
1549 accessible by BL2 immediately upon entry.
1550
1551 ::
1552
1553 meminfo.total_base = Base address of secure RAM visible to BL2
1554 meminfo.total_size = Size of secure RAM visible to BL2
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001555
Soby Mathew97b1bff2018-09-27 16:46:41 +01001556 By default, BL1 places this ``meminfo`` structure at the end of secure
1557 memory visible to BL2.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001558
Soby Mathewb1bf0442018-02-16 14:52:52 +00001559 It is possible for the platform to decide where it wants to place the
1560 ``meminfo`` structure for BL2 or restrict the amount of memory visible to
1561 BL2 by overriding the weak default implementation of
1562 ``bl1_plat_handle_post_image_load`` API.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001563
1564The following functions need to be implemented by the platform port to enable
1565BL1 to perform the above tasks.
1566
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001567Function : bl1_early_platform_setup() [mandatory]
1568~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001569
1570::
1571
1572 Argument : void
1573 Return : void
1574
1575This function executes with the MMU and data caches disabled. It is only called
1576by the primary CPU.
1577
Dan Handley610e7e12018-03-01 18:44:00 +00001578On Arm standard platforms, this function:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001579
1580- Enables a secure instance of SP805 to act as the Trusted Watchdog.
1581
1582- Initializes a UART (PL011 console), which enables access to the ``printf``
1583 family of functions in BL1.
1584
1585- Enables issuing of snoop and DVM (Distributed Virtual Memory) requests to
1586 the CCI slave interface corresponding to the cluster that includes the
1587 primary CPU.
1588
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001589Function : bl1_plat_arch_setup() [mandatory]
1590~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001591
1592::
1593
1594 Argument : void
1595 Return : void
1596
1597This function performs any platform-specific and architectural setup that the
1598platform requires. Platform-specific setup might include configuration of
1599memory controllers and the interconnect.
1600
Dan Handley610e7e12018-03-01 18:44:00 +00001601In Arm standard platforms, this function enables the MMU.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001602
1603This function helps fulfill requirement 2 above.
1604
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001605Function : bl1_platform_setup() [mandatory]
1606~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001607
1608::
1609
1610 Argument : void
1611 Return : void
1612
1613This function executes with the MMU and data caches enabled. It is responsible
1614for performing any remaining platform-specific setup that can occur after the
1615MMU and data cache have been enabled.
1616
Roberto Vargas0cd866c2017-12-12 10:39:44 +00001617if support for multiple boot sources is required, it initializes the boot
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001618sequence used by plat_try_next_boot_source().
Roberto Vargas0cd866c2017-12-12 10:39:44 +00001619
Dan Handley610e7e12018-03-01 18:44:00 +00001620In Arm standard platforms, this function initializes the storage abstraction
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001621layer used to load the next bootloader image.
1622
1623This function helps fulfill requirement 4 above.
1624
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001625Function : bl1_plat_sec_mem_layout() [mandatory]
1626~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001627
1628::
1629
1630 Argument : void
1631 Return : meminfo *
1632
1633This function should only be called on the cold boot path. It executes with the
1634MMU and data caches enabled. The pointer returned by this function must point to
1635a ``meminfo`` structure containing the extents and availability of secure RAM for
1636the BL1 stage.
1637
1638::
1639
1640 meminfo.total_base = Base address of secure RAM visible to BL1
1641 meminfo.total_size = Size of secure RAM visible to BL1
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001642
1643This information is used by BL1 to load the BL2 image in secure RAM. BL1 also
1644populates a similar structure to tell BL2 the extents of memory available for
1645its own use.
1646
1647This function helps fulfill requirements 4 and 5 above.
1648
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001649Function : bl1_plat_prepare_exit() [optional]
1650~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001651
1652::
1653
1654 Argument : entry_point_info_t *
1655 Return : void
1656
1657This function is called prior to exiting BL1 in response to the
1658``BL1_SMC_RUN_IMAGE`` SMC request raised by BL2. It should be used to perform
1659platform specific clean up or bookkeeping operations before transferring
1660control to the next image. It receives the address of the ``entry_point_info_t``
1661structure passed from BL2. This function runs with MMU disabled.
1662
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001663Function : bl1_plat_set_ep_info() [optional]
1664~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001665
1666::
1667
1668 Argument : unsigned int image_id, entry_point_info_t *ep_info
1669 Return : void
1670
1671This function allows platforms to override ``ep_info`` for the given ``image_id``.
1672
1673The default implementation just returns.
1674
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001675Function : bl1_plat_get_next_image_id() [optional]
1676~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001677
1678::
1679
1680 Argument : void
1681 Return : unsigned int
1682
1683This and the following function must be overridden to enable the FWU feature.
1684
1685BL1 calls this function after platform setup to identify the next image to be
1686loaded and executed. If the platform returns ``BL2_IMAGE_ID`` then BL1 proceeds
1687with the normal boot sequence, which loads and executes BL2. If the platform
1688returns a different image id, BL1 assumes that Firmware Update is required.
1689
Dan Handley610e7e12018-03-01 18:44:00 +00001690The default implementation always returns ``BL2_IMAGE_ID``. The Arm development
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001691platforms override this function to detect if firmware update is required, and
1692if so, return the first image in the firmware update process.
1693
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001694Function : bl1_plat_get_image_desc() [optional]
1695~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001696
1697::
1698
1699 Argument : unsigned int image_id
1700 Return : image_desc_t *
1701
1702BL1 calls this function to get the image descriptor information ``image_desc_t``
1703for the provided ``image_id`` from the platform.
1704
Dan Handley610e7e12018-03-01 18:44:00 +00001705The default implementation always returns a common BL2 image descriptor. Arm
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001706standard platforms return an image descriptor corresponding to BL2 or one of
1707the firmware update images defined in the Trusted Board Boot Requirements
1708specification.
1709
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001710Function : bl1_plat_handle_pre_image_load() [optional]
1711~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001712
1713::
1714
Soby Mathew2f38ce32018-02-08 17:45:12 +00001715 Argument : unsigned int image_id
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001716 Return : int
1717
1718This function can be used by the platforms to update/use image information
Soby Mathew2f38ce32018-02-08 17:45:12 +00001719corresponding to ``image_id``. This function is invoked in BL1, both in cold
1720boot and FWU code path, before loading the image.
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001721
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001722Function : bl1_plat_handle_post_image_load() [optional]
1723~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001724
1725::
1726
Soby Mathew2f38ce32018-02-08 17:45:12 +00001727 Argument : unsigned int image_id
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001728 Return : int
1729
1730This function can be used by the platforms to update/use image information
Soby Mathew2f38ce32018-02-08 17:45:12 +00001731corresponding to ``image_id``. This function is invoked in BL1, both in cold
1732boot and FWU code path, after loading and authenticating the image.
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001733
Soby Mathewb1bf0442018-02-16 14:52:52 +00001734The default weak implementation of this function calculates the amount of
1735Trusted SRAM that can be used by BL2 and allocates a ``meminfo_t``
1736structure at the beginning of this free memory and populates it. The address
1737of ``meminfo_t`` structure is updated in ``arg1`` of the entrypoint
1738information to BL2.
1739
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001740Function : bl1_plat_fwu_done() [optional]
1741~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001742
1743::
1744
1745 Argument : unsigned int image_id, uintptr_t image_src,
1746 unsigned int image_size
1747 Return : void
1748
1749BL1 calls this function when the FWU process is complete. It must not return.
1750The platform may override this function to take platform specific action, for
1751example to initiate the normal boot flow.
1752
1753The default implementation spins forever.
1754
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001755Function : bl1_plat_mem_check() [mandatory]
1756~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001757
1758::
1759
1760 Argument : uintptr_t mem_base, unsigned int mem_size,
1761 unsigned int flags
1762 Return : int
1763
1764BL1 calls this function while handling FWU related SMCs, more specifically when
1765copying or authenticating an image. Its responsibility is to ensure that the
1766region of memory identified by ``mem_base`` and ``mem_size`` is mapped in BL1, and
1767that this memory corresponds to either a secure or non-secure memory region as
1768indicated by the security state of the ``flags`` argument.
1769
1770This function can safely assume that the value resulting from the addition of
1771``mem_base`` and ``mem_size`` fits into a ``uintptr_t`` type variable and does not
1772overflow.
1773
1774This function must return 0 on success, a non-null error code otherwise.
1775
1776The default implementation of this function asserts therefore platforms must
1777override it when using the FWU feature.
1778
1779Boot Loader Stage 2 (BL2)
1780-------------------------
1781
1782The BL2 stage is executed only by the primary CPU, which is determined in BL1
1783using the ``platform_is_primary_cpu()`` function. BL1 passed control to BL2 at
Soby Mathew97b1bff2018-09-27 16:46:41 +01001784``BL2_BASE``. BL2 executes in Secure EL1 and and invokes
1785``plat_get_bl_image_load_info()`` to retrieve the list of images to load from
1786non-volatile storage to secure/non-secure RAM. After all the images are loaded
1787then BL2 invokes ``plat_get_next_bl_params()`` to get the list of executable
1788images to be passed to the next BL image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001789
1790The following functions must be implemented by the platform port to enable BL2
1791to perform the above tasks.
1792
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001793Function : bl2_early_platform_setup2() [mandatory]
1794~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001795
1796::
1797
Soby Mathew97b1bff2018-09-27 16:46:41 +01001798 Argument : u_register_t, u_register_t, u_register_t, u_register_t
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001799 Return : void
1800
1801This function executes with the MMU and data caches disabled. It is only called
Soby Mathew97b1bff2018-09-27 16:46:41 +01001802by the primary CPU. The 4 arguments are passed by BL1 to BL2 and these arguments
1803are platform specific.
1804
1805On Arm standard platforms, the arguments received are :
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001806
Manish V Badarkhe81414512020-06-24 15:58:38 +01001807 arg0 - Points to load address of FW_CONFIG
Soby Mathew97b1bff2018-09-27 16:46:41 +01001808
1809 arg1 - ``meminfo`` structure populated by BL1. The platform copies
1810 the contents of ``meminfo`` as it may be subsequently overwritten by BL2.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001811
Dan Handley610e7e12018-03-01 18:44:00 +00001812On Arm standard platforms, this function also:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001813
1814- Initializes a UART (PL011 console), which enables access to the ``printf``
1815 family of functions in BL2.
1816
1817- Initializes the storage abstraction layer used to load further bootloader
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001818 images. It is necessary to do this early on platforms with a SCP_BL2 image,
1819 since the later ``bl2_platform_setup`` must be done after SCP_BL2 is loaded.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001820
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001821Function : bl2_plat_arch_setup() [mandatory]
1822~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001823
1824::
1825
1826 Argument : void
1827 Return : void
1828
1829This function executes with the MMU and data caches disabled. It is only called
1830by the primary CPU.
1831
1832The purpose of this function is to perform any architectural initialization
1833that varies across platforms.
1834
Dan Handley610e7e12018-03-01 18:44:00 +00001835On Arm standard platforms, this function enables the MMU.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001836
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001837Function : bl2_platform_setup() [mandatory]
1838~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001839
1840::
1841
1842 Argument : void
1843 Return : void
1844
1845This function may execute with the MMU and data caches enabled if the platform
1846port does the necessary initialization in ``bl2_plat_arch_setup()``. It is only
1847called by the primary CPU.
1848
1849The purpose of this function is to perform any platform initialization
1850specific to BL2.
1851
Dan Handley610e7e12018-03-01 18:44:00 +00001852In Arm standard platforms, this function performs security setup, including
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001853configuration of the TrustZone controller to allow non-secure masters access
1854to most of DRAM. Part of DRAM is reserved for secure world use.
1855
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001856Function : bl2_plat_handle_pre_image_load() [optional]
1857~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001858
1859::
1860
1861 Argument : unsigned int
1862 Return : int
1863
1864This function can be used by the platforms to update/use image information
Masahiro Yamada02a0d3d2018-02-01 16:45:51 +09001865for given ``image_id``. This function is currently invoked in BL2 before
Soby Mathew97b1bff2018-09-27 16:46:41 +01001866loading each image.
Masahiro Yamada02a0d3d2018-02-01 16:45:51 +09001867
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001868Function : bl2_plat_handle_post_image_load() [optional]
1869~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Masahiro Yamada02a0d3d2018-02-01 16:45:51 +09001870
1871::
1872
1873 Argument : unsigned int
1874 Return : int
1875
1876This function can be used by the platforms to update/use image information
1877for given ``image_id``. This function is currently invoked in BL2 after
Soby Mathew97b1bff2018-09-27 16:46:41 +01001878loading each image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001879
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001880Function : bl2_plat_preload_setup [optional]
1881~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001882
1883::
John Tsichritzisee10e792018-06-06 09:38:10 +01001884
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001885 Argument : void
1886 Return : void
1887
1888This optional function performs any BL2 platform initialization
1889required before image loading, that is not done later in
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001890bl2_platform_setup(). Specifically, if support for multiple
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001891boot sources is required, it initializes the boot sequence used by
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001892plat_try_next_boot_source().
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001893
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001894Function : plat_try_next_boot_source() [optional]
1895~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001896
1897::
John Tsichritzisee10e792018-06-06 09:38:10 +01001898
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001899 Argument : void
1900 Return : int
1901
1902This optional function passes to the next boot source in the redundancy
1903sequence.
1904
1905This function moves the current boot redundancy source to the next
1906element in the boot sequence. If there are no more boot sources then it
1907must return 0, otherwise it must return 1. The default implementation
1908of this always returns 0.
1909
Roberto Vargasb1584272017-11-20 13:36:10 +00001910Boot Loader Stage 2 (BL2) at EL3
1911--------------------------------
1912
Dan Handley610e7e12018-03-01 18:44:00 +00001913When the platform has a non-TF-A Boot ROM it is desirable to jump
1914directly to BL2 instead of TF-A BL1. In this case BL2 is expected to
Paul Beesleyf8640672019-04-12 14:19:42 +01001915execute at EL3 instead of executing at EL1. Refer to the :ref:`Firmware Design`
1916document for more information.
Roberto Vargasb1584272017-11-20 13:36:10 +00001917
1918All mandatory functions of BL2 must be implemented, except the functions
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001919bl2_early_platform_setup and bl2_el3_plat_arch_setup, because
1920their work is done now by bl2_el3_early_platform_setup and
1921bl2_el3_plat_arch_setup. These functions should generally implement
1922the bl1_plat_xxx() and bl2_plat_xxx() functionality combined.
Roberto Vargasb1584272017-11-20 13:36:10 +00001923
1924
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001925Function : bl2_el3_early_platform_setup() [mandatory]
1926~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roberto Vargasb1584272017-11-20 13:36:10 +00001927
1928::
John Tsichritzisee10e792018-06-06 09:38:10 +01001929
Roberto Vargasb1584272017-11-20 13:36:10 +00001930 Argument : u_register_t, u_register_t, u_register_t, u_register_t
1931 Return : void
1932
1933This function executes with the MMU and data caches disabled. It is only called
1934by the primary CPU. This function receives four parameters which can be used
1935by the platform to pass any needed information from the Boot ROM to BL2.
1936
Dan Handley610e7e12018-03-01 18:44:00 +00001937On Arm standard platforms, this function does the following:
Roberto Vargasb1584272017-11-20 13:36:10 +00001938
1939- Initializes a UART (PL011 console), which enables access to the ``printf``
1940 family of functions in BL2.
1941
1942- Initializes the storage abstraction layer used to load further bootloader
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001943 images. It is necessary to do this early on platforms with a SCP_BL2 image,
1944 since the later ``bl2_platform_setup`` must be done after SCP_BL2 is loaded.
Roberto Vargasb1584272017-11-20 13:36:10 +00001945
1946- Initializes the private variables that define the memory layout used.
1947
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001948Function : bl2_el3_plat_arch_setup() [mandatory]
1949~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roberto Vargasb1584272017-11-20 13:36:10 +00001950
1951::
John Tsichritzisee10e792018-06-06 09:38:10 +01001952
Roberto Vargasb1584272017-11-20 13:36:10 +00001953 Argument : void
1954 Return : void
1955
1956This function executes with the MMU and data caches disabled. It is only called
1957by the primary CPU.
1958
1959The purpose of this function is to perform any architectural initialization
1960that varies across platforms.
1961
Dan Handley610e7e12018-03-01 18:44:00 +00001962On Arm standard platforms, this function enables the MMU.
Roberto Vargasb1584272017-11-20 13:36:10 +00001963
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001964Function : bl2_el3_plat_prepare_exit() [optional]
1965~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Roberto Vargasb1584272017-11-20 13:36:10 +00001966
1967::
John Tsichritzisee10e792018-06-06 09:38:10 +01001968
Roberto Vargasb1584272017-11-20 13:36:10 +00001969 Argument : void
1970 Return : void
1971
1972This function is called prior to exiting BL2 and run the next image.
1973It should be used to perform platform specific clean up or bookkeeping
1974operations before transferring control to the next image. This function
1975runs with MMU disabled.
1976
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001977FWU Boot Loader Stage 2 (BL2U)
1978------------------------------
1979
1980The AP Firmware Updater Configuration, BL2U, is an optional part of the FWU
1981process and is executed only by the primary CPU. BL1 passes control to BL2U at
1982``BL2U_BASE``. BL2U executes in Secure-EL1 and is responsible for:
1983
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001984#. (Optional) Transferring the optional SCP_BL2U binary image from AP secure
1985 memory to SCP RAM. BL2U uses the SCP_BL2U ``image_info`` passed by BL1.
1986 ``SCP_BL2U_BASE`` defines the address in AP secure memory where SCP_BL2U
1987 should be copied from. Subsequent handling of the SCP_BL2U image is
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001988 implemented by the platform specific ``bl2u_plat_handle_scp_bl2u()`` function.
1989 If ``SCP_BL2U_BASE`` is not defined then this step is not performed.
1990
1991#. Any platform specific setup required to perform the FWU process. For
Dan Handley610e7e12018-03-01 18:44:00 +00001992 example, Arm standard platforms initialize the TZC controller so that the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001993 normal world can access DDR memory.
1994
1995The following functions must be implemented by the platform port to enable
1996BL2U to perform the tasks mentioned above.
1997
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01001998Function : bl2u_early_platform_setup() [mandatory]
1999~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002000
2001::
2002
2003 Argument : meminfo *mem_info, void *plat_info
2004 Return : void
2005
2006This function executes with the MMU and data caches disabled. It is only
2007called by the primary CPU. The arguments to this function is the address
2008of the ``meminfo`` structure and platform specific info provided by BL1.
2009
2010The platform may copy the contents of the ``mem_info`` and ``plat_info`` into
2011private storage as the original memory may be subsequently overwritten by BL2U.
2012
Dan Handley610e7e12018-03-01 18:44:00 +00002013On Arm CSS platforms ``plat_info`` is interpreted as an ``image_info_t`` structure,
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002014to extract SCP_BL2U image information, which is then copied into a private
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002015variable.
2016
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002017Function : bl2u_plat_arch_setup() [mandatory]
2018~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002019
2020::
2021
2022 Argument : void
2023 Return : void
2024
2025This function executes with the MMU and data caches disabled. It is only
2026called by the primary CPU.
2027
2028The purpose of this function is to perform any architectural initialization
2029that varies across platforms, for example enabling the MMU (since the memory
2030map differs across platforms).
2031
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002032Function : bl2u_platform_setup() [mandatory]
2033~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002034
2035::
2036
2037 Argument : void
2038 Return : void
2039
2040This function may execute with the MMU and data caches enabled if the platform
2041port does the necessary initialization in ``bl2u_plat_arch_setup()``. It is only
2042called by the primary CPU.
2043
2044The purpose of this function is to perform any platform initialization
2045specific to BL2U.
2046
Dan Handley610e7e12018-03-01 18:44:00 +00002047In Arm standard platforms, this function performs security setup, including
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002048configuration of the TrustZone controller to allow non-secure masters access
2049to most of DRAM. Part of DRAM is reserved for secure world use.
2050
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002051Function : bl2u_plat_handle_scp_bl2u() [optional]
2052~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002053
2054::
2055
2056 Argument : void
2057 Return : int
2058
2059This function is used to perform any platform-specific actions required to
2060handle the SCP firmware. Typically it transfers the image into SCP memory using
2061a platform-specific protocol and waits until SCP executes it and signals to the
2062Application Processor (AP) for BL2U execution to continue.
2063
2064This function returns 0 on success, a negative error code otherwise.
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002065This function is included if SCP_BL2U_BASE is defined.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002066
2067Boot Loader Stage 3-1 (BL31)
2068----------------------------
2069
2070During cold boot, the BL31 stage is executed only by the primary CPU. This is
2071determined in BL1 using the ``platform_is_primary_cpu()`` function. BL1 passes
2072control to BL31 at ``BL31_BASE``. During warm boot, BL31 is executed by all
2073CPUs. BL31 executes at EL3 and is responsible for:
2074
2075#. Re-initializing all architectural and platform state. Although BL1 performs
2076 some of this initialization, BL31 remains resident in EL3 and must ensure
2077 that EL3 architectural and platform state is completely initialized. It
2078 should make no assumptions about the system state when it receives control.
2079
2080#. Passing control to a normal world BL image, pre-loaded at a platform-
Soby Mathew97b1bff2018-09-27 16:46:41 +01002081 specific address by BL2. On ARM platforms, BL31 uses the ``bl_params`` list
2082 populated by BL2 in memory to do this.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002083
2084#. Providing runtime firmware services. Currently, BL31 only implements a
2085 subset of the Power State Coordination Interface (PSCI) API as a runtime
Boyan Karatotev907d38b2022-11-22 12:01:09 +00002086 service. See :ref:`psci_in_bl31` below for details of porting the PSCI
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002087 implementation.
2088
2089#. Optionally passing control to the BL32 image, pre-loaded at a platform-
Paul Beesley1fbc97b2019-01-11 18:26:51 +00002090 specific address by BL2. BL31 exports a set of APIs that allow runtime
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002091 services to specify the security state in which the next image should be
Soby Mathew97b1bff2018-09-27 16:46:41 +01002092 executed and run the corresponding image. On ARM platforms, BL31 uses the
2093 ``bl_params`` list populated by BL2 in memory to do this.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002094
2095If BL31 is a reset vector, It also needs to handle the reset as specified in
2096section 2.2 before the tasks described above.
2097
2098The following functions must be implemented by the platform port to enable BL31
2099to perform the above tasks.
2100
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002101Function : bl31_early_platform_setup2() [mandatory]
2102~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002103
2104::
2105
Soby Mathew97b1bff2018-09-27 16:46:41 +01002106 Argument : u_register_t, u_register_t, u_register_t, u_register_t
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002107 Return : void
2108
2109This function executes with the MMU and data caches disabled. It is only called
Soby Mathew97b1bff2018-09-27 16:46:41 +01002110by the primary CPU. BL2 can pass 4 arguments to BL31 and these arguments are
2111platform specific.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002112
Soby Mathew97b1bff2018-09-27 16:46:41 +01002113In Arm standard platforms, the arguments received are :
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002114
Soby Mathew97b1bff2018-09-27 16:46:41 +01002115 arg0 - The pointer to the head of `bl_params_t` list
2116 which is list of executable images following BL31,
2117
2118 arg1 - Points to load address of SOC_FW_CONFIG if present
Mikael Olsson0232da22021-02-12 17:30:16 +01002119 except in case of Arm FVP and Juno platform.
Manish V Badarkhe81414512020-06-24 15:58:38 +01002120
Mikael Olsson0232da22021-02-12 17:30:16 +01002121 In case of Arm FVP and Juno platform, points to load address
Manish V Badarkhe81414512020-06-24 15:58:38 +01002122 of FW_CONFIG.
Soby Mathew97b1bff2018-09-27 16:46:41 +01002123
2124 arg2 - Points to load address of HW_CONFIG if present
2125
2126 arg3 - A special value to verify platform parameters from BL2 to BL31. Not
2127 used in release builds.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002128
Soby Mathew97b1bff2018-09-27 16:46:41 +01002129The function runs through the `bl_param_t` list and extracts the entry point
2130information for BL32 and BL33. It also performs the following:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002131
2132- Initialize a UART (PL011 console), which enables access to the ``printf``
2133 family of functions in BL31.
2134
2135- Enable issuing of snoop and DVM (Distributed Virtual Memory) requests to the
2136 CCI slave interface corresponding to the cluster that includes the primary
2137 CPU.
2138
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002139Function : bl31_plat_arch_setup() [mandatory]
2140~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002141
2142::
2143
2144 Argument : void
2145 Return : void
2146
2147This function executes with the MMU and data caches disabled. It is only called
2148by the primary CPU.
2149
2150The purpose of this function is to perform any architectural initialization
2151that varies across platforms.
2152
Dan Handley610e7e12018-03-01 18:44:00 +00002153On Arm standard platforms, this function enables the MMU.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002154
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002155Function : bl31_platform_setup() [mandatory]
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002156~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2157
2158::
2159
2160 Argument : void
2161 Return : void
2162
2163This function may execute with the MMU and data caches enabled if the platform
2164port does the necessary initialization in ``bl31_plat_arch_setup()``. It is only
2165called by the primary CPU.
2166
2167The purpose of this function is to complete platform initialization so that both
2168BL31 runtime services and normal world software can function correctly.
2169
Dan Handley610e7e12018-03-01 18:44:00 +00002170On Arm standard platforms, this function does the following:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002171
2172- Initialize the generic interrupt controller.
2173
2174 Depending on the GIC driver selected by the platform, the appropriate GICv2
2175 or GICv3 initialization will be done, which mainly consists of:
2176
2177 - Enable secure interrupts in the GIC CPU interface.
2178 - Disable the legacy interrupt bypass mechanism.
2179 - Configure the priority mask register to allow interrupts of all priorities
2180 to be signaled to the CPU interface.
2181 - Mark SGIs 8-15 and the other secure interrupts on the platform as secure.
2182 - Target all secure SPIs to CPU0.
2183 - Enable these secure interrupts in the GIC distributor.
2184 - Configure all other interrupts as non-secure.
2185 - Enable signaling of secure interrupts in the GIC distributor.
2186
2187- Enable system-level implementation of the generic timer counter through the
2188 memory mapped interface.
2189
2190- Grant access to the system counter timer module
2191
2192- Initialize the power controller device.
2193
2194 In particular, initialise the locks that prevent concurrent accesses to the
2195 power controller device.
2196
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002197Function : bl31_plat_runtime_setup() [optional]
2198~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002199
2200::
2201
2202 Argument : void
2203 Return : void
2204
2205The purpose of this function is allow the platform to perform any BL31 runtime
2206setup just prior to BL31 exit during cold boot. The default weak
Julius Werneraae9bb12017-09-18 16:49:48 -07002207implementation of this function will invoke ``console_switch_state()`` to switch
2208console output to consoles marked for use in the ``runtime`` state.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002209
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002210Function : bl31_plat_get_next_image_ep_info() [mandatory]
2211~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002212
2213::
2214
Sandrine Bailleux842117d2018-05-14 14:25:47 +02002215 Argument : uint32_t
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002216 Return : entry_point_info *
2217
2218This function may execute with the MMU and data caches enabled if the platform
2219port does the necessary initializations in ``bl31_plat_arch_setup()``.
2220
2221This function is called by ``bl31_main()`` to retrieve information provided by
2222BL2 for the next image in the security state specified by the argument. BL31
2223uses this information to pass control to that image in the specified security
2224state. This function must return a pointer to the ``entry_point_info`` structure
2225(that was copied during ``bl31_early_platform_setup()``) if the image exists. It
2226should return NULL otherwise.
2227
Javier Almansa Sobrino7176a772021-11-24 18:37:37 +00002228Function : plat_rmmd_get_cca_attest_token() [mandatory when ENABLE_RME == 1]
Soby Mathew294e1cf2022-03-22 16:19:39 +00002229~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2230
2231::
2232
2233 Argument : uintptr_t, size_t *, uintptr_t, size_t
2234 Return : int
2235
2236This function returns the Platform attestation token.
2237
2238The parameters of the function are:
2239
2240 arg0 - A pointer to the buffer where the Platform token should be copied by
2241 this function. The buffer must be big enough to hold the Platform
2242 token.
2243
2244 arg1 - Contains the size (in bytes) of the buffer passed in arg0. The
2245 function returns the platform token length in this parameter.
2246
2247 arg2 - A pointer to the buffer where the challenge object is stored.
2248
2249 arg3 - The length of the challenge object in bytes. Possible values are 32,
2250 48 and 64.
2251
2252The function returns 0 on success, -EINVAL on failure.
2253
Javier Almansa Sobrino7176a772021-11-24 18:37:37 +00002254Function : plat_rmmd_get_cca_realm_attest_key() [mandatory when ENABLE_RME == 1]
2255~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Soby Mathewf05d93a2022-03-22 16:21:19 +00002256
2257::
2258
2259 Argument : uintptr_t, size_t *, unsigned int
2260 Return : int
2261
2262This function returns the delegated realm attestation key which will be used to
2263sign Realm attestation token. The API currently only supports P-384 ECC curve
2264key.
2265
2266The parameters of the function are:
2267
2268 arg0 - A pointer to the buffer where the attestation key should be copied
2269 by this function. The buffer must be big enough to hold the
2270 attestation key.
2271
2272 arg1 - Contains the size (in bytes) of the buffer passed in arg0. The
2273 function returns the attestation key length in this parameter.
2274
2275 arg2 - The type of the elliptic curve to which the requested attestation key
2276 belongs.
2277
2278The function returns 0 on success, -EINVAL on failure.
2279
Javier Almansa Sobrino7176a772021-11-24 18:37:37 +00002280Function : plat_rmmd_get_el3_rmm_shared_mem() [when ENABLE_RME == 1]
2281~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2282
2283::
2284
2285 Argument : uintptr_t *
2286 Return : size_t
2287
2288This function returns the size of the shared area between EL3 and RMM (or 0 on
2289failure). A pointer to the shared area (or a NULL pointer on failure) is stored
2290in the pointer passed as argument.
2291
Javier Almansa Sobrino4165e842022-04-25 17:18:15 +01002292Function : plat_rmmd_load_manifest() [when ENABLE_RME == 1]
2293~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2294
2295::
2296
2297 Arguments : rmm_manifest_t *manifest
2298 Return : int
2299
2300When ENABLE_RME is enabled, this function populates a boot manifest for the
2301RMM image and stores it in the area specified by manifest.
2302
2303When ENABLE_RME is disabled, this function is not used.
2304
Jeenu Viswambharane834ee12018-04-27 15:17:03 +01002305Function : bl31_plat_enable_mmu [optional]
2306~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2307
2308::
2309
2310 Argument : uint32_t
2311 Return : void
2312
2313This function enables the MMU. The boot code calls this function with MMU and
2314caches disabled. This function should program necessary registers to enable
2315translation, and upon return, the MMU on the calling PE must be enabled.
2316
2317The function must honor flags passed in the first argument. These flags are
2318defined by the translation library, and can be found in the file
2319``include/lib/xlat_tables/xlat_mmu_helpers.h``.
2320
2321On DynamIQ systems, this function must not use stack while enabling MMU, which
Paul Beesley1fbc97b2019-01-11 18:26:51 +00002322is how the function in xlat table library version 2 is implemented.
Jeenu Viswambharane834ee12018-04-27 15:17:03 +01002323
Alexei Fedorovf41355c2019-09-13 14:11:59 +01002324Function : plat_init_apkey [optional]
2325~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Antonio Nino Diaz25cda672019-02-19 11:53:51 +00002326
2327::
2328
2329 Argument : void
Alexei Fedorovf41355c2019-09-13 14:11:59 +01002330 Return : uint128_t
Antonio Nino Diaz25cda672019-02-19 11:53:51 +00002331
Alexei Fedorovf41355c2019-09-13 14:11:59 +01002332This function returns the 128-bit value which can be used to program ARMv8.3
2333pointer authentication keys.
Antonio Nino Diaz25cda672019-02-19 11:53:51 +00002334
2335The value should be obtained from a reliable source of randomness.
2336
2337This function is only needed if ARMv8.3 pointer authentication is used in the
Alexei Fedorovf41355c2019-09-13 14:11:59 +01002338Trusted Firmware by building with ``BRANCH_PROTECTION`` option set to non-zero.
Antonio Nino Diaz25cda672019-02-19 11:53:51 +00002339
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002340Function : plat_get_syscnt_freq2() [mandatory]
2341~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002342
2343::
2344
2345 Argument : void
2346 Return : unsigned int
2347
2348This function is used by the architecture setup code to retrieve the counter
2349frequency for the CPU's generic timer. This value will be programmed into the
Dan Handley610e7e12018-03-01 18:44:00 +00002350``CNTFRQ_EL0`` register. In Arm standard platforms, it returns the base frequency
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002351of the system counter, which is retrieved from the first entry in the frequency
2352modes table.
2353
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002354#define : PLAT_PERCPU_BAKERY_LOCK_SIZE [optional]
2355~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002356
2357When ``USE_COHERENT_MEM = 0``, this constant defines the total memory (in
2358bytes) aligned to the cache line boundary that should be allocated per-cpu to
2359accommodate all the bakery locks.
2360
2361If this constant is not defined when ``USE_COHERENT_MEM = 0``, the linker
Chris Kay33bfc5e2023-02-14 11:30:04 +00002362calculates the size of the ``.bakery_lock`` input section, aligns it to the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002363nearest ``CACHE_WRITEBACK_GRANULE``, multiplies it with ``PLATFORM_CORE_COUNT``
2364and stores the result in a linker symbol. This constant prevents a platform
2365from relying on the linker and provide a more efficient mechanism for
2366accessing per-cpu bakery lock information.
2367
2368If this constant is defined and its value is not equal to the value
2369calculated by the linker then a link time assertion is raised. A compile time
2370assertion is raised if the value of the constant is not aligned to the cache
2371line boundary.
2372
Paul Beesleyf8640672019-04-12 14:19:42 +01002373.. _porting_guide_sdei_requirements:
2374
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002375SDEI porting requirements
2376~~~~~~~~~~~~~~~~~~~~~~~~~
2377
Paul Beesley606d8072019-03-13 13:58:02 +00002378The |SDEI| dispatcher requires the platform to provide the following macros
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002379and functions, of which some are optional, and some others mandatory.
2380
2381Macros
2382......
2383
2384Macro: PLAT_SDEI_NORMAL_PRI [mandatory]
2385^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2386
2387This macro must be defined to the EL3 exception priority level associated with
Paul Beesley606d8072019-03-13 13:58:02 +00002388Normal |SDEI| events on the platform. This must have a higher value
2389(therefore of lower priority) than ``PLAT_SDEI_CRITICAL_PRI``.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002390
2391Macro: PLAT_SDEI_CRITICAL_PRI [mandatory]
2392^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2393
2394This macro must be defined to the EL3 exception priority level associated with
Paul Beesley606d8072019-03-13 13:58:02 +00002395Critical |SDEI| events on the platform. This must have a lower value
2396(therefore of higher priority) than ``PLAT_SDEI_NORMAL_PRI``.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002397
Paul Beesley606d8072019-03-13 13:58:02 +00002398**Note**: |SDEI| exception priorities must be the lowest among Secure
2399priorities. Among the |SDEI| exceptions, Critical |SDEI| priority must
2400be higher than Normal |SDEI| priority.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002401
2402Functions
2403.........
2404
Sandrine Bailleux95db98b2020-05-15 12:05:51 +02002405Function: int plat_sdei_validate_entry_point() [optional]
2406^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002407
2408::
2409
Sandrine Bailleux95db98b2020-05-15 12:05:51 +02002410 Argument: uintptr_t ep, unsigned int client_mode
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002411 Return: int
2412
Sandrine Bailleux95db98b2020-05-15 12:05:51 +02002413This function validates the entry point address of the event handler provided by
2414the client for both event registration and *Complete and Resume* |SDEI| calls.
2415The function ensures that the address is valid in the client translation regime.
2416
2417The second argument is the exception level that the client is executing in. It
2418can be Non-Secure EL1 or Non-Secure EL2.
2419
2420The function must return ``0`` for successful validation, or ``-1`` upon failure.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002421
Dan Handley610e7e12018-03-01 18:44:00 +00002422The default implementation always returns ``0``. On Arm platforms, this function
Sandrine Bailleux95db98b2020-05-15 12:05:51 +02002423translates the entry point address within the client translation regime and
2424further ensures that the resulting physical address is located in Non-secure
2425DRAM.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002426
2427Function: void plat_sdei_handle_masked_trigger(uint64_t mpidr, unsigned int intr) [optional]
2428^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2429
2430::
2431
2432 Argument: uint64_t
2433 Argument: unsigned int
2434 Return: void
2435
Paul Beesley606d8072019-03-13 13:58:02 +00002436|SDEI| specification requires that a PE comes out of reset with the events
2437masked. The client therefore is expected to call ``PE_UNMASK`` to unmask
2438|SDEI| events on the PE. No |SDEI| events can be dispatched until such
2439time.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002440
Paul Beesley606d8072019-03-13 13:58:02 +00002441Should a PE receive an interrupt that was bound to an |SDEI| event while the
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002442events are masked on the PE, the dispatcher implementation invokes the function
2443``plat_sdei_handle_masked_trigger``. The MPIDR of the PE that received the
2444interrupt and the interrupt ID are passed as parameters.
2445
2446The default implementation only prints out a warning message.
2447
Jimmy Brisson26c5b5c2020-06-22 14:18:42 -05002448.. _porting_guide_trng_requirements:
2449
2450TRNG porting requirements
2451~~~~~~~~~~~~~~~~~~~~~~~~~
2452
2453The |TRNG| backend requires the platform to provide the following values
2454and mandatory functions.
2455
2456Values
2457......
2458
2459value: uuid_t plat_trng_uuid [mandatory]
2460^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2461
2462This value must be defined to the UUID of the TRNG backend that is specific to
Jayanth Dodderi Chidanand7c7faff2022-10-11 17:16:07 +01002463the hardware after ``plat_entropy_setup`` function is called. This value must
Jimmy Brisson26c5b5c2020-06-22 14:18:42 -05002464conform to the SMCCC calling convention; The most significant 32 bits of the
2465UUID must not equal ``0xffffffff`` or the signed integer ``-1`` as this value in
2466w0 indicates failure to get a TRNG source.
2467
2468Functions
2469.........
2470
2471Function: void plat_entropy_setup(void) [mandatory]
2472^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2473
2474::
2475
2476 Argument: none
2477 Return: none
2478
2479This function is expected to do platform-specific initialization of any TRNG
2480hardware. This may include generating a UUID from a hardware-specific seed.
2481
2482Function: bool plat_get_entropy(uint64_t \*out) [mandatory]
2483^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2484
2485::
2486
2487 Argument: uint64_t *
2488 Return: bool
2489 Out : when the return value is true, the entropy has been written into the
2490 storage pointed to
2491
2492This function writes entropy into storage provided by the caller. If no entropy
2493is available, it must return false and the storage must not be written.
2494
Boyan Karatotev907d38b2022-11-22 12:01:09 +00002495.. _psci_in_bl31:
2496
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002497Power State Coordination Interface (in BL31)
2498--------------------------------------------
2499
Dan Handley610e7e12018-03-01 18:44:00 +00002500The TF-A implementation of the PSCI API is based around the concept of a
2501*power domain*. A *power domain* is a CPU or a logical group of CPUs which
2502share some state on which power management operations can be performed as
2503specified by `PSCI`_. Each CPU in the system is assigned a cpu index which is
2504a unique number between ``0`` and ``PLATFORM_CORE_COUNT - 1``. The
2505*power domains* are arranged in a hierarchical tree structure and each
2506*power domain* can be identified in a system by the cpu index of any CPU that
2507is part of that domain and a *power domain level*. A processing element (for
2508example, a CPU) is at level 0. If the *power domain* node above a CPU is a
2509logical grouping of CPUs that share some state, then level 1 is that group of
2510CPUs (for example, a cluster), and level 2 is a group of clusters (for
2511example, the system). More details on the power domain topology and its
Paul Beesleyf8640672019-04-12 14:19:42 +01002512organization can be found in :ref:`PSCI Power Domain Tree Structure`.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002513
2514BL31's platform initialization code exports a pointer to the platform-specific
2515power management operations required for the PSCI implementation to function
2516correctly. This information is populated in the ``plat_psci_ops`` structure. The
2517PSCI implementation calls members of the ``plat_psci_ops`` structure for performing
2518power management operations on the power domains. For example, the target
2519CPU is specified by its ``MPIDR`` in a PSCI ``CPU_ON`` call. The ``pwr_domain_on()``
2520handler (if present) is called for the CPU power domain.
2521
2522The ``power-state`` parameter of a PSCI ``CPU_SUSPEND`` call can be used to
2523describe composite power states specific to a platform. The PSCI implementation
Antonio Nino Diaz56b68ad2019-02-28 13:35:21 +00002524defines a generic representation of the power-state parameter, which is an
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002525array of local power states where each index corresponds to a power domain
2526level. Each entry contains the local power state the power domain at that power
2527level could enter. It depends on the ``validate_power_state()`` handler to
2528convert the power-state parameter (possibly encoding a composite power state)
2529passed in a PSCI ``CPU_SUSPEND`` call to this representation.
2530
2531The following functions form part of platform port of PSCI functionality.
2532
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002533Function : plat_psci_stat_accounting_start() [optional]
2534~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002535
2536::
2537
2538 Argument : const psci_power_state_t *
2539 Return : void
2540
2541This is an optional hook that platforms can implement for residency statistics
2542accounting before entering a low power state. The ``pwr_domain_state`` field of
2543``state_info`` (first argument) can be inspected if stat accounting is done
2544differently at CPU level versus higher levels. As an example, if the element at
2545index 0 (CPU power level) in the ``pwr_domain_state`` array indicates a power down
2546state, special hardware logic may be programmed in order to keep track of the
2547residency statistics. For higher levels (array indices > 0), the residency
2548statistics could be tracked in software using PMF. If ``ENABLE_PMF`` is set, the
2549default implementation will use PMF to capture timestamps.
2550
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002551Function : plat_psci_stat_accounting_stop() [optional]
2552~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002553
2554::
2555
2556 Argument : const psci_power_state_t *
2557 Return : void
2558
2559This is an optional hook that platforms can implement for residency statistics
2560accounting after exiting from a low power state. The ``pwr_domain_state`` field
2561of ``state_info`` (first argument) can be inspected if stat accounting is done
2562differently at CPU level versus higher levels. As an example, if the element at
2563index 0 (CPU power level) in the ``pwr_domain_state`` array indicates a power down
2564state, special hardware logic may be programmed in order to keep track of the
2565residency statistics. For higher levels (array indices > 0), the residency
2566statistics could be tracked in software using PMF. If ``ENABLE_PMF`` is set, the
2567default implementation will use PMF to capture timestamps.
2568
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002569Function : plat_psci_stat_get_residency() [optional]
2570~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002571
2572::
2573
Deepika Bhavnani4287c0c2019-12-13 10:23:18 -06002574 Argument : unsigned int, const psci_power_state_t *, unsigned int
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002575 Return : u_register_t
2576
2577This is an optional interface that is is invoked after resuming from a low power
2578state and provides the time spent resident in that low power state by the power
2579domain at a particular power domain level. When a CPU wakes up from suspend,
2580all its parent power domain levels are also woken up. The generic PSCI code
2581invokes this function for each parent power domain that is resumed and it
2582identified by the ``lvl`` (first argument) parameter. The ``state_info`` (second
2583argument) describes the low power state that the power domain has resumed from.
2584The current CPU is the first CPU in the power domain to resume from the low
2585power state and the ``last_cpu_idx`` (third parameter) is the index of the last
2586CPU in the power domain to suspend and may be needed to calculate the residency
2587for that power domain.
2588
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002589Function : plat_get_target_pwr_state() [optional]
2590~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002591
2592::
2593
2594 Argument : unsigned int, const plat_local_state_t *, unsigned int
2595 Return : plat_local_state_t
2596
2597The PSCI generic code uses this function to let the platform participate in
2598state coordination during a power management operation. The function is passed
2599a pointer to an array of platform specific local power state ``states`` (second
2600argument) which contains the requested power state for each CPU at a particular
2601power domain level ``lvl`` (first argument) within the power domain. The function
2602is expected to traverse this array of upto ``ncpus`` (third argument) and return
2603a coordinated target power state by the comparing all the requested power
2604states. The target power state should not be deeper than any of the requested
2605power states.
2606
2607A weak definition of this API is provided by default wherein it assumes
2608that the platform assigns a local state value in order of increasing depth
2609of the power state i.e. for two power states X & Y, if X < Y
2610then X represents a shallower power state than Y. As a result, the
2611coordinated target local power state for a power domain will be the minimum
2612of the requested local power state values.
2613
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002614Function : plat_get_power_domain_tree_desc() [mandatory]
2615~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002616
2617::
2618
2619 Argument : void
2620 Return : const unsigned char *
2621
2622This function returns a pointer to the byte array containing the power domain
2623topology tree description. The format and method to construct this array are
Paul Beesleyf8640672019-04-12 14:19:42 +01002624described in :ref:`PSCI Power Domain Tree Structure`. The BL31 PSCI
2625initialization code requires this array to be described by the platform, either
2626statically or dynamically, to initialize the power domain topology tree. In case
2627the array is populated dynamically, then plat_core_pos_by_mpidr() and
2628plat_my_core_pos() should also be implemented suitably so that the topology tree
2629description matches the CPU indices returned by these APIs. These APIs together
2630form the platform interface for the PSCI topology framework.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002631
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002632Function : plat_setup_psci_ops() [mandatory]
2633~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002634
2635::
2636
2637 Argument : uintptr_t, const plat_psci_ops **
2638 Return : int
2639
2640This function may execute with the MMU and data caches enabled if the platform
2641port does the necessary initializations in ``bl31_plat_arch_setup()``. It is only
2642called by the primary CPU.
2643
2644This function is called by PSCI initialization code. Its purpose is to let
2645the platform layer know about the warm boot entrypoint through the
2646``sec_entrypoint`` (first argument) and to export handler routines for
2647platform-specific psci power management actions by populating the passed
2648pointer with a pointer to BL31's private ``plat_psci_ops`` structure.
2649
2650A description of each member of this structure is given below. Please refer to
Dan Handley610e7e12018-03-01 18:44:00 +00002651the Arm FVP specific implementation of these handlers in
Paul Beesleyf8640672019-04-12 14:19:42 +01002652``plat/arm/board/fvp/fvp_pm.c`` as an example. For each PSCI function that the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002653platform wants to support, the associated operation or operations in this
2654structure must be provided and implemented (Refer section 4 of
Paul Beesleyf8640672019-04-12 14:19:42 +01002655:ref:`Firmware Design` for the PSCI API supported in TF-A). To disable a PSCI
Dan Handley610e7e12018-03-01 18:44:00 +00002656function in a platform port, the operation should be removed from this
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002657structure instead of providing an empty implementation.
2658
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002659plat_psci_ops.cpu_standby()
2660...........................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002661
2662Perform the platform-specific actions to enter the standby state for a cpu
2663indicated by the passed argument. This provides a fast path for CPU standby
Paul Beesley1fbc97b2019-01-11 18:26:51 +00002664wherein overheads of PSCI state management and lock acquisition is avoided.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002665For this handler to be invoked by the PSCI ``CPU_SUSPEND`` API implementation,
2666the suspend state type specified in the ``power-state`` parameter should be
2667STANDBY and the target power domain level specified should be the CPU. The
2668handler should put the CPU into a low power retention state (usually by
2669issuing a wfi instruction) and ensure that it can be woken up from that
2670state by a normal interrupt. The generic code expects the handler to succeed.
2671
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002672plat_psci_ops.pwr_domain_on()
2673.............................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002674
2675Perform the platform specific actions to power on a CPU, specified
2676by the ``MPIDR`` (first argument). The generic code expects the platform to
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002677return PSCI_E_SUCCESS on success or PSCI_E_INTERN_FAIL for any failure.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002678
Varun Wadekar77dd4f12023-04-25 14:03:27 +01002679plat_psci_ops.pwr_domain_off_early() [optional]
2680...............................................
2681
2682This optional function performs the platform specific actions to check if
2683powering off the calling CPU and its higher parent power domain levels as
2684indicated by the ``target_state`` (first argument) is possible or allowed.
2685
2686The ``target_state`` encodes the platform coordinated target local power states
2687for the CPU power domain and its parent power domain levels.
2688
2689For this handler, the local power state for the CPU power domain will be a
2690power down state where as it could be either power down, retention or run state
2691for the higher power domain levels depending on the result of state
2692coordination. The generic code expects PSCI_E_DENIED return code if the
2693platform thinks that CPU_OFF should not proceed on the calling CPU.
2694
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002695plat_psci_ops.pwr_domain_off()
2696..............................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002697
2698Perform the platform specific actions to prepare to power off the calling CPU
2699and its higher parent power domain levels as indicated by the ``target_state``
2700(first argument). It is called by the PSCI ``CPU_OFF`` API implementation.
2701
2702The ``target_state`` encodes the platform coordinated target local power states
2703for the CPU power domain and its parent power domain levels. The handler
2704needs to perform power management operation corresponding to the local state
2705at each power level.
2706
2707For this handler, the local power state for the CPU power domain will be a
2708power down state where as it could be either power down, retention or run state
2709for the higher power domain levels depending on the result of state
2710coordination. The generic code expects the handler to succeed.
2711
Wing Lic0dc6392023-05-04 08:31:19 -07002712plat_psci_ops.pwr_domain_validate_suspend() [optional]
2713......................................................
2714
2715This is an optional function that is only compiled into the build if the build
2716option ``PSCI_OS_INIT_MODE`` is enabled.
2717
2718If implemented, this function allows the platform to perform platform specific
2719validations based on hardware states. The generic code expects this function to
2720return PSCI_E_SUCCESS on success, or either PSCI_E_DENIED or
2721PSCI_E_INVALID_PARAMS as appropriate for any invalid requests.
2722
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002723plat_psci_ops.pwr_domain_suspend_pwrdown_early() [optional]
2724...........................................................
Varun Wadekarae87f4b2017-07-10 16:02:05 -07002725
2726This optional function may be used as a performance optimization to replace
2727or complement pwr_domain_suspend() on some platforms. Its calling semantics
2728are identical to pwr_domain_suspend(), except the PSCI implementation only
2729calls this function when suspending to a power down state, and it guarantees
2730that data caches are enabled.
2731
2732When HW_ASSISTED_COHERENCY = 0, the PSCI implementation disables data caches
2733before calling pwr_domain_suspend(). If the target_state corresponds to a
2734power down state and it is safe to perform some or all of the platform
2735specific actions in that function with data caches enabled, it may be more
2736efficient to move those actions to this function. When HW_ASSISTED_COHERENCY
2737= 1, data caches remain enabled throughout, and so there is no advantage to
2738moving platform specific actions to this function.
2739
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002740plat_psci_ops.pwr_domain_suspend()
2741..................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002742
2743Perform the platform specific actions to prepare to suspend the calling
2744CPU and its higher parent power domain levels as indicated by the
2745``target_state`` (first argument). It is called by the PSCI ``CPU_SUSPEND``
2746API implementation.
2747
2748The ``target_state`` has a similar meaning as described in
2749the ``pwr_domain_off()`` operation. It encodes the platform coordinated
2750target local power states for the CPU power domain and its parent
2751power domain levels. The handler needs to perform power management operation
2752corresponding to the local state at each power level. The generic code
2753expects the handler to succeed.
2754
Douglas Raillarda84996b2017-08-02 16:57:32 +01002755The difference between turning a power domain off versus suspending it is that
2756in the former case, the power domain is expected to re-initialize its state
2757when it is next powered on (see ``pwr_domain_on_finish()``). In the latter
2758case, the power domain is expected to save enough state so that it can resume
2759execution by restoring this state when its powered on (see
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002760``pwr_domain_suspend_finish()``).
2761
Douglas Raillarda84996b2017-08-02 16:57:32 +01002762When suspending a core, the platform can also choose to power off the GICv3
2763Redistributor and ITS through an implementation-defined sequence. To achieve
2764this safely, the ITS context must be saved first. The architectural part is
2765implemented by the ``gicv3_its_save_disable()`` helper, but most of the needed
2766sequence is implementation defined and it is therefore the responsibility of
2767the platform code to implement the necessary sequence. Then the GIC
2768Redistributor context can be saved using the ``gicv3_rdistif_save()`` helper.
2769Powering off the Redistributor requires the implementation to support it and it
2770is the responsibility of the platform code to execute the right implementation
2771defined sequence.
2772
2773When a system suspend is requested, the platform can also make use of the
2774``gicv3_distif_save()`` helper to save the context of the GIC Distributor after
2775it has saved the context of the Redistributors and ITS of all the cores in the
2776system. The context of the Distributor can be large and may require it to be
2777allocated in a special area if it cannot fit in the platform's global static
2778data, for example in DRAM. The Distributor can then be powered down using an
2779implementation-defined sequence.
2780
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002781plat_psci_ops.pwr_domain_pwr_down_wfi()
2782.......................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002783
2784This is an optional function and, if implemented, is expected to perform
2785platform specific actions including the ``wfi`` invocation which allows the
2786CPU to powerdown. Since this function is invoked outside the PSCI locks,
2787the actions performed in this hook must be local to the CPU or the platform
2788must ensure that races between multiple CPUs cannot occur.
2789
2790The ``target_state`` has a similar meaning as described in the ``pwr_domain_off()``
2791operation and it encodes the platform coordinated target local power states for
2792the CPU power domain and its parent power domain levels. This function must
Boyan Karatotev43771f32022-10-05 13:41:56 +01002793not return back to the caller (by calling wfi in an infinite loop to ensure
2794some CPUs power down mitigations work properly).
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002795
2796If this function is not implemented by the platform, PSCI generic
2797implementation invokes ``psci_power_down_wfi()`` for power down.
2798
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002799plat_psci_ops.pwr_domain_on_finish()
2800....................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002801
2802This function is called by the PSCI implementation after the calling CPU is
2803powered on and released from reset in response to an earlier PSCI ``CPU_ON`` call.
2804It performs the platform-specific setup required to initialize enough state for
2805this CPU to enter the normal world and also provide secure runtime firmware
2806services.
2807
2808The ``target_state`` (first argument) is the prior state of the power domains
2809immediately before the CPU was turned on. It indicates which power domains
2810above the CPU might require initialization due to having previously been in
2811low power states. The generic code expects the handler to succeed.
2812
Madhukar Pappireddy33bd5142019-08-12 18:31:33 -05002813plat_psci_ops.pwr_domain_on_finish_late() [optional]
2814...........................................................
2815
2816This optional function is called by the PSCI implementation after the calling
2817CPU is fully powered on with respective data caches enabled. The calling CPU and
2818the associated cluster are guaranteed to be participating in coherency. This
2819function gives the flexibility to perform any platform-specific actions safely,
2820such as initialization or modification of shared data structures, without the
2821overhead of explicit cache maintainace operations.
2822
2823The ``target_state`` has a similar meaning as described in the ``pwr_domain_on_finish()``
2824operation. The generic code expects the handler to succeed.
2825
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002826plat_psci_ops.pwr_domain_suspend_finish()
2827.........................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002828
2829This function is called by the PSCI implementation after the calling CPU is
2830powered on and released from reset in response to an asynchronous wakeup
2831event, for example a timer interrupt that was programmed by the CPU during the
2832``CPU_SUSPEND`` call or ``SYSTEM_SUSPEND`` call. It performs the platform-specific
2833setup required to restore the saved state for this CPU to resume execution
2834in the normal world and also provide secure runtime firmware services.
2835
2836The ``target_state`` (first argument) has a similar meaning as described in
2837the ``pwr_domain_on_finish()`` operation. The generic code expects the platform
2838to succeed.
2839
Douglas Raillarda84996b2017-08-02 16:57:32 +01002840If the Distributor, Redistributors or ITS have been powered off as part of a
2841suspend, their context must be restored in this function in the reverse order
2842to how they were saved during suspend sequence.
2843
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002844plat_psci_ops.system_off()
2845..........................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002846
2847This function is called by PSCI implementation in response to a ``SYSTEM_OFF``
2848call. It performs the platform-specific system poweroff sequence after
2849notifying the Secure Payload Dispatcher.
2850
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002851plat_psci_ops.system_reset()
2852............................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002853
2854This function is called by PSCI implementation in response to a ``SYSTEM_RESET``
2855call. It performs the platform-specific system reset sequence after
2856notifying the Secure Payload Dispatcher.
2857
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002858plat_psci_ops.validate_power_state()
2859....................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002860
2861This function is called by the PSCI implementation during the ``CPU_SUSPEND``
2862call to validate the ``power_state`` parameter of the PSCI API and if valid,
2863populate it in ``req_state`` (second argument) array as power domain level
2864specific local states. If the ``power_state`` is invalid, the platform must
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002865return PSCI_E_INVALID_PARAMS as error, which is propagated back to the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002866normal world PSCI client.
2867
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002868plat_psci_ops.validate_ns_entrypoint()
2869......................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002870
2871This function is called by the PSCI implementation during the ``CPU_SUSPEND``,
2872``SYSTEM_SUSPEND`` and ``CPU_ON`` calls to validate the non-secure ``entry_point``
2873parameter passed by the normal world. If the ``entry_point`` is invalid,
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002874the platform must return PSCI_E_INVALID_ADDRESS as error, which is
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002875propagated back to the normal world PSCI client.
2876
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002877plat_psci_ops.get_sys_suspend_power_state()
2878...........................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002879
2880This function is called by the PSCI implementation during the ``SYSTEM_SUSPEND``
2881call to get the ``req_state`` parameter from platform which encodes the power
2882domain level specific local states to suspend to system affinity level. The
2883``req_state`` will be utilized to do the PSCI state coordination and
2884``pwr_domain_suspend()`` will be invoked with the coordinated target state to
2885enter system suspend.
2886
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002887plat_psci_ops.get_pwr_lvl_state_idx()
2888.....................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002889
2890This is an optional function and, if implemented, is invoked by the PSCI
2891implementation to convert the ``local_state`` (first argument) at a specified
2892``pwr_lvl`` (second argument) to an index between 0 and
2893``PLAT_MAX_PWR_LVL_STATES`` - 1. This function is only needed if the platform
2894supports more than two local power states at each power domain level, that is
2895``PLAT_MAX_PWR_LVL_STATES`` is greater than 2, and needs to account for these
2896local power states.
2897
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002898plat_psci_ops.translate_power_state_by_mpidr()
2899..............................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002900
2901This is an optional function and, if implemented, verifies the ``power_state``
2902(second argument) parameter of the PSCI API corresponding to a target power
2903domain. The target power domain is identified by using both ``MPIDR`` (first
2904argument) and the power domain level encoded in ``power_state``. The power domain
2905level specific local states are to be extracted from ``power_state`` and be
2906populated in the ``output_state`` (third argument) array. The functionality
2907is similar to the ``validate_power_state`` function described above and is
2908envisaged to be used in case the validity of ``power_state`` depend on the
2909targeted power domain. If the ``power_state`` is invalid for the targeted power
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002910domain, the platform must return PSCI_E_INVALID_PARAMS as error. If this
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002911function is not implemented, then the generic implementation relies on
2912``validate_power_state`` function to translate the ``power_state``.
2913
2914This function can also be used in case the platform wants to support local
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002915power state encoding for ``power_state`` parameter of PSCI_STAT_COUNT/RESIDENCY
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002916APIs as described in Section 5.18 of `PSCI`_.
2917
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002918plat_psci_ops.get_node_hw_state()
2919.................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002920
2921This is an optional function. If implemented this function is intended to return
2922the power state of a node (identified by the first parameter, the ``MPIDR``) in
2923the power domain topology (identified by the second parameter, ``power_level``),
2924as retrieved from a power controller or equivalent component on the platform.
2925Upon successful completion, the implementation must map and return the final
2926status among ``HW_ON``, ``HW_OFF`` or ``HW_STANDBY``. Upon encountering failures, it
2927must return either ``PSCI_E_INVALID_PARAMS`` or ``PSCI_E_NOT_SUPPORTED`` as
2928appropriate.
2929
2930Implementations are not expected to handle ``power_levels`` greater than
2931``PLAT_MAX_PWR_LVL``.
2932
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002933plat_psci_ops.system_reset2()
2934.............................
Roberto Vargasd963e3e2017-09-12 10:28:35 +01002935
2936This is an optional function. If implemented this function is
2937called during the ``SYSTEM_RESET2`` call to perform a reset
2938based on the first parameter ``reset_type`` as specified in
2939`PSCI`_. The parameter ``cookie`` can be used to pass additional
2940reset information. If the ``reset_type`` is not supported, the
2941function must return ``PSCI_E_NOT_SUPPORTED``. For architectural
2942resets, all failures must return ``PSCI_E_INVALID_PARAMETERS``
2943and vendor reset can return other PSCI error codes as defined
2944in `PSCI`_. On success this function will not return.
2945
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002946plat_psci_ops.write_mem_protect()
2947.................................
Roberto Vargasd963e3e2017-09-12 10:28:35 +01002948
2949This is an optional function. If implemented it enables or disables the
2950``MEM_PROTECT`` functionality based on the value of ``val``.
2951A non-zero value enables ``MEM_PROTECT`` and a value of zero
2952disables it. Upon encountering failures it must return a negative value
2953and on success it must return 0.
2954
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002955plat_psci_ops.read_mem_protect()
2956................................
Roberto Vargasd963e3e2017-09-12 10:28:35 +01002957
2958This is an optional function. If implemented it returns the current
2959state of ``MEM_PROTECT`` via the ``val`` parameter. Upon encountering
2960failures it must return a negative value and on success it must
2961return 0.
2962
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002963plat_psci_ops.mem_protect_chk()
2964...............................
Roberto Vargasd963e3e2017-09-12 10:28:35 +01002965
2966This is an optional function. If implemented it checks if a memory
2967region defined by a base address ``base`` and with a size of ``length``
2968bytes is protected by ``MEM_PROTECT``. If the region is protected
2969then it must return 0, otherwise it must return a negative number.
2970
Paul Beesleyf8640672019-04-12 14:19:42 +01002971.. _porting_guide_imf_in_bl31:
2972
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002973Interrupt Management framework (in BL31)
2974----------------------------------------
2975
2976BL31 implements an Interrupt Management Framework (IMF) to manage interrupts
2977generated in either security state and targeted to EL1 or EL2 in the non-secure
2978state or EL3/S-EL1 in the secure state. The design of this framework is
Paul Beesleyf8640672019-04-12 14:19:42 +01002979described in the :ref:`Interrupt Management Framework`
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002980
2981A platform should export the following APIs to support the IMF. The following
Paul Beesley1fbc97b2019-01-11 18:26:51 +00002982text briefly describes each API and its implementation in Arm standard
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002983platforms. The API implementation depends upon the type of interrupt controller
Dan Handley610e7e12018-03-01 18:44:00 +00002984present in the platform. Arm standard platform layer supports both
2985`Arm Generic Interrupt Controller version 2.0 (GICv2)`_
2986and `3.0 (GICv3)`_. Juno builds the Arm platform layer to use GICv2 and the
2987FVP can be configured to use either GICv2 or GICv3 depending on the build flag
Paul Beesleyd2fcc4e2019-05-29 13:59:40 +01002988``FVP_USE_GIC_DRIVER`` (See :ref:`build_options_arm_fvp_platform` for more
2989details).
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002990
Madhukar Pappireddy86350ae2020-07-29 09:37:25 -05002991See also: :ref:`Interrupt Controller Abstraction APIs<Platform Interrupt Controller API>`.
Jeenu Viswambharanb1e957e2017-09-22 08:32:09 +01002992
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01002993Function : plat_interrupt_type_to_line() [mandatory]
2994~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002995
2996::
2997
2998 Argument : uint32_t, uint32_t
2999 Return : uint32_t
3000
Dan Handley610e7e12018-03-01 18:44:00 +00003001The Arm processor signals an interrupt exception either through the IRQ or FIQ
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003002interrupt line. The specific line that is signaled depends on how the interrupt
3003controller (IC) reports different interrupt types from an execution context in
3004either security state. The IMF uses this API to determine which interrupt line
3005the platform IC uses to signal each type of interrupt supported by the framework
3006from a given security state. This API must be invoked at EL3.
3007
3008The first parameter will be one of the ``INTR_TYPE_*`` values (see
Paul Beesleyf8640672019-04-12 14:19:42 +01003009:ref:`Interrupt Management Framework`) indicating the target type of the
3010interrupt, the second parameter is the security state of the originating
3011execution context. The return result is the bit position in the ``SCR_EL3``
3012register of the respective interrupt trap: IRQ=1, FIQ=2.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003013
Dan Handley610e7e12018-03-01 18:44:00 +00003014In the case of Arm standard platforms using GICv2, S-EL1 interrupts are
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003015configured as FIQs and Non-secure interrupts as IRQs from either security
3016state.
3017
Dan Handley610e7e12018-03-01 18:44:00 +00003018In the case of Arm standard platforms using GICv3, the interrupt line to be
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003019configured depends on the security state of the execution context when the
3020interrupt is signalled and are as follows:
3021
3022- The S-EL1 interrupts are signaled as IRQ in S-EL0/1 context and as FIQ in
3023 NS-EL0/1/2 context.
3024- The Non secure interrupts are signaled as FIQ in S-EL0/1 context and as IRQ
3025 in the NS-EL0/1/2 context.
3026- The EL3 interrupts are signaled as FIQ in both S-EL0/1 and NS-EL0/1/2
3027 context.
3028
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003029Function : plat_ic_get_pending_interrupt_type() [mandatory]
3030~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003031
3032::
3033
3034 Argument : void
3035 Return : uint32_t
3036
3037This API returns the type of the highest priority pending interrupt at the
3038platform IC. The IMF uses the interrupt type to retrieve the corresponding
3039handler function. ``INTR_TYPE_INVAL`` is returned when there is no interrupt
3040pending. The valid interrupt types that can be returned are ``INTR_TYPE_EL3``,
3041``INTR_TYPE_S_EL1`` and ``INTR_TYPE_NS``. This API must be invoked at EL3.
3042
Dan Handley610e7e12018-03-01 18:44:00 +00003043In the case of Arm standard platforms using GICv2, the *Highest Priority
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003044Pending Interrupt Register* (``GICC_HPPIR``) is read to determine the id of
3045the pending interrupt. The type of interrupt depends upon the id value as
3046follows.
3047
3048#. id < 1022 is reported as a S-EL1 interrupt
3049#. id = 1022 is reported as a Non-secure interrupt.
3050#. id = 1023 is reported as an invalid interrupt type.
3051
Dan Handley610e7e12018-03-01 18:44:00 +00003052In the case of Arm standard platforms using GICv3, the system register
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003053``ICC_HPPIR0_EL1``, *Highest Priority Pending group 0 Interrupt Register*,
3054is read to determine the id of the pending interrupt. The type of interrupt
3055depends upon the id value as follows.
3056
3057#. id = ``PENDING_G1S_INTID`` (1020) is reported as a S-EL1 interrupt
3058#. id = ``PENDING_G1NS_INTID`` (1021) is reported as a Non-secure interrupt.
3059#. id = ``GIC_SPURIOUS_INTERRUPT`` (1023) is reported as an invalid interrupt type.
3060#. All other interrupt id's are reported as EL3 interrupt.
3061
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003062Function : plat_ic_get_pending_interrupt_id() [mandatory]
3063~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003064
3065::
3066
3067 Argument : void
3068 Return : uint32_t
3069
3070This API returns the id of the highest priority pending interrupt at the
3071platform IC. ``INTR_ID_UNAVAILABLE`` is returned when there is no interrupt
3072pending.
3073
Dan Handley610e7e12018-03-01 18:44:00 +00003074In the case of Arm standard platforms using GICv2, the *Highest Priority
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003075Pending Interrupt Register* (``GICC_HPPIR``) is read to determine the id of the
3076pending interrupt. The id that is returned by API depends upon the value of
3077the id read from the interrupt controller as follows.
3078
3079#. id < 1022. id is returned as is.
3080#. id = 1022. The *Aliased Highest Priority Pending Interrupt Register*
3081 (``GICC_AHPPIR``) is read to determine the id of the non-secure interrupt.
3082 This id is returned by the API.
3083#. id = 1023. ``INTR_ID_UNAVAILABLE`` is returned.
3084
Dan Handley610e7e12018-03-01 18:44:00 +00003085In the case of Arm standard platforms using GICv3, if the API is invoked from
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003086EL3, the system register ``ICC_HPPIR0_EL1``, *Highest Priority Pending Interrupt
3087group 0 Register*, is read to determine the id of the pending interrupt. The id
3088that is returned by API depends upon the value of the id read from the
3089interrupt controller as follows.
3090
3091#. id < ``PENDING_G1S_INTID`` (1020). id is returned as is.
3092#. id = ``PENDING_G1S_INTID`` (1020) or ``PENDING_G1NS_INTID`` (1021). The system
3093 register ``ICC_HPPIR1_EL1``, *Highest Priority Pending Interrupt group 1
3094 Register* is read to determine the id of the group 1 interrupt. This id
3095 is returned by the API as long as it is a valid interrupt id
3096#. If the id is any of the special interrupt identifiers,
3097 ``INTR_ID_UNAVAILABLE`` is returned.
3098
3099When the API invoked from S-EL1 for GICv3 systems, the id read from system
3100register ``ICC_HPPIR1_EL1``, *Highest Priority Pending group 1 Interrupt
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003101Register*, is returned if is not equal to GIC_SPURIOUS_INTERRUPT (1023) else
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003102``INTR_ID_UNAVAILABLE`` is returned.
3103
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003104Function : plat_ic_acknowledge_interrupt() [mandatory]
3105~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003106
3107::
3108
3109 Argument : void
3110 Return : uint32_t
3111
3112This API is used by the CPU to indicate to the platform IC that processing of
Jeenu Viswambharan055af4b2017-10-24 15:13:59 +01003113the highest pending interrupt has begun. It should return the raw, unmodified
3114value obtained from the interrupt controller when acknowledging an interrupt.
3115The actual interrupt number shall be extracted from this raw value using the API
Madhukar Pappireddy86350ae2020-07-29 09:37:25 -05003116`plat_ic_get_interrupt_id()<plat_ic_get_interrupt_id>`.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003117
Dan Handley610e7e12018-03-01 18:44:00 +00003118This function in Arm standard platforms using GICv2, reads the *Interrupt
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003119Acknowledge Register* (``GICC_IAR``). This changes the state of the highest
3120priority pending interrupt from pending to active in the interrupt controller.
Jeenu Viswambharan055af4b2017-10-24 15:13:59 +01003121It returns the value read from the ``GICC_IAR``, unmodified.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003122
Dan Handley610e7e12018-03-01 18:44:00 +00003123In the case of Arm standard platforms using GICv3, if the API is invoked
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003124from EL3, the function reads the system register ``ICC_IAR0_EL1``, *Interrupt
3125Acknowledge Register group 0*. If the API is invoked from S-EL1, the function
3126reads the system register ``ICC_IAR1_EL1``, *Interrupt Acknowledge Register
3127group 1*. The read changes the state of the highest pending interrupt from
3128pending to active in the interrupt controller. The value read is returned
Jeenu Viswambharan055af4b2017-10-24 15:13:59 +01003129unmodified.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003130
3131The TSP uses this API to start processing of the secure physical timer
3132interrupt.
3133
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003134Function : plat_ic_end_of_interrupt() [mandatory]
3135~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003136
3137::
3138
3139 Argument : uint32_t
3140 Return : void
3141
3142This API is used by the CPU to indicate to the platform IC that processing of
3143the interrupt corresponding to the id (passed as the parameter) has
3144finished. The id should be the same as the id returned by the
3145``plat_ic_acknowledge_interrupt()`` API.
3146
Dan Handley610e7e12018-03-01 18:44:00 +00003147Arm standard platforms write the id to the *End of Interrupt Register*
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003148(``GICC_EOIR``) in case of GICv2, and to ``ICC_EOIR0_EL1`` or ``ICC_EOIR1_EL1``
3149system register in case of GICv3 depending on where the API is invoked from,
3150EL3 or S-EL1. This deactivates the corresponding interrupt in the interrupt
3151controller.
3152
3153The TSP uses this API to finish processing of the secure physical timer
3154interrupt.
3155
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003156Function : plat_ic_get_interrupt_type() [mandatory]
3157~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003158
3159::
3160
3161 Argument : uint32_t
3162 Return : uint32_t
3163
3164This API returns the type of the interrupt id passed as the parameter.
3165``INTR_TYPE_INVAL`` is returned if the id is invalid. If the id is valid, a valid
3166interrupt type (one of ``INTR_TYPE_EL3``, ``INTR_TYPE_S_EL1`` and ``INTR_TYPE_NS``) is
3167returned depending upon how the interrupt has been configured by the platform
3168IC. This API must be invoked at EL3.
3169
Dan Handley610e7e12018-03-01 18:44:00 +00003170Arm standard platforms using GICv2 configures S-EL1 interrupts as Group0 interrupts
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003171and Non-secure interrupts as Group1 interrupts. It reads the group value
3172corresponding to the interrupt id from the relevant *Interrupt Group Register*
3173(``GICD_IGROUPRn``). It uses the group value to determine the type of interrupt.
3174
Dan Handley610e7e12018-03-01 18:44:00 +00003175In the case of Arm standard platforms using GICv3, both the *Interrupt Group
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003176Register* (``GICD_IGROUPRn``) and *Interrupt Group Modifier Register*
3177(``GICD_IGRPMODRn``) is read to figure out whether the interrupt is configured
3178as Group 0 secure interrupt, Group 1 secure interrupt or Group 1 NS interrupt.
3179
Manish Pandey3161fa52022-11-02 16:30:09 +00003180Common helper functions
3181-----------------------
Govindraj Rajab6709b02023-02-21 17:43:55 +00003182Function : elx_panic()
3183~~~~~~~~~~~~~~~~~~~~~~
Manish Pandey3161fa52022-11-02 16:30:09 +00003184
Govindraj Rajab6709b02023-02-21 17:43:55 +00003185::
3186
3187 Argument : void
3188 Return : void
3189
3190This API is called from assembly files when reporting a critical failure
3191that has occured in lower EL and is been trapped in EL3. This call
3192**must not** return.
Manish Pandey3161fa52022-11-02 16:30:09 +00003193
Govindraj Rajaa796b1b2023-01-16 17:35:07 +00003194Function : el3_panic()
3195~~~~~~~~~~~~~~~~~~~~~~
Manish Pandey3161fa52022-11-02 16:30:09 +00003196
3197::
3198
3199 Argument : void
3200 Return : void
3201
3202This API is called from assembly files when encountering a critical failure that
Govindraj Rajaa796b1b2023-01-16 17:35:07 +00003203cannot be recovered from. This function assumes that it is invoked from a C
3204runtime environment i.e. valid stack exists. This call **must not** return.
Manish Pandey3161fa52022-11-02 16:30:09 +00003205
3206Function : panic()
3207~~~~~~~~~~~~~~~~~~
3208
3209::
3210
3211 Argument : void
3212 Return : void
3213
3214This API called from C files when encountering a critical failure that cannot
3215be recovered from. This function in turn prints backtrace (if enabled) and calls
Govindraj Rajaa796b1b2023-01-16 17:35:07 +00003216el3_panic(). This call **must not** return.
Manish Pandey3161fa52022-11-02 16:30:09 +00003217
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003218Crash Reporting mechanism (in BL31)
3219-----------------------------------
3220
3221BL31 implements a crash reporting mechanism which prints the various registers
Antonio Nino Diaz4bac0452018-10-16 14:32:34 +01003222of the CPU to enable quick crash analysis and debugging. This mechanism relies
Paul Beesley1fbc97b2019-01-11 18:26:51 +00003223on the platform implementing ``plat_crash_console_init``,
Antonio Nino Diaz4bac0452018-10-16 14:32:34 +01003224``plat_crash_console_putc`` and ``plat_crash_console_flush``.
3225
3226The file ``plat/common/aarch64/crash_console_helpers.S`` contains sample
3227implementation of all of them. Platforms may include this file to their
3228makefiles in order to benefit from them. By default, they will cause the crash
Julius Werneraae9bb12017-09-18 16:49:48 -07003229output to be routed over the normal console infrastructure and get printed on
3230consoles configured to output in crash state. ``console_set_scope()`` can be
3231used to control whether a console is used for crash output.
Paul Beesleyba3ed402019-03-13 16:20:44 +00003232
3233.. note::
3234 Platforms are responsible for making sure that they only mark consoles for
3235 use in the crash scope that are able to support this, i.e. that are written
3236 in assembly and conform with the register clobber rules for putc()
3237 (x0-x2, x16-x17) and flush() (x0-x3, x16-x17) crash callbacks.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003238
Julius Werneraae9bb12017-09-18 16:49:48 -07003239In some cases (such as debugging very early crashes that happen before the
3240normal boot console can be set up), platforms may want to control crash output
Julius Werner1338c9c2018-11-19 14:25:55 -08003241more explicitly. These platforms may instead provide custom implementations for
3242these. They are executed outside of a C environment and without a stack. Many
3243console drivers provide functions named ``console_xxx_core_init/putc/flush``
3244that are designed to be used by these functions. See Arm platforms (like juno)
3245for an example of this.
Antonio Nino Diaz4bac0452018-10-16 14:32:34 +01003246
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003247Function : plat_crash_console_init [mandatory]
3248~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003249
3250::
3251
3252 Argument : void
3253 Return : int
3254
3255This API is used by the crash reporting mechanism to initialize the crash
Julius Werneraae9bb12017-09-18 16:49:48 -07003256console. It must only use the general purpose registers x0 through x7 to do the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003257initialization and returns 1 on success.
3258
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003259Function : plat_crash_console_putc [mandatory]
3260~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003261
3262::
3263
3264 Argument : int
3265 Return : int
3266
3267This API is used by the crash reporting mechanism to print a character on the
3268designated crash console. It must only use general purpose registers x1 and
3269x2 to do its work. The parameter and the return value are in general purpose
3270register x0.
3271
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003272Function : plat_crash_console_flush [mandatory]
3273~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003274
3275::
3276
3277 Argument : void
Jimmy Brisson39f9eee2020-08-05 13:44:05 -05003278 Return : void
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003279
3280This API is used by the crash reporting mechanism to force write of all buffered
3281data on the designated crash console. It should only use general purpose
Jimmy Brisson39f9eee2020-08-05 13:44:05 -05003282registers x0 through x5 to do its work.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003283
Manish Pandey9c9f38a2020-06-30 00:46:08 +01003284.. _External Abort handling and RAS Support:
3285
Jeenu Viswambharane34bf582018-10-12 08:48:36 +01003286External Abort handling and RAS Support
3287---------------------------------------
Jeenu Viswambharanbf235bc2018-07-12 10:00:01 +01003288
3289Function : plat_ea_handler
3290~~~~~~~~~~~~~~~~~~~~~~~~~~
3291
3292::
3293
3294 Argument : int
3295 Argument : uint64_t
3296 Argument : void *
3297 Argument : void *
3298 Argument : uint64_t
3299 Return : void
3300
3301This function is invoked by the RAS framework for the platform to handle an
3302External Abort received at EL3. The intention of the function is to attempt to
3303resolve the cause of External Abort and return; if that's not possible, to
3304initiate orderly shutdown of the system.
3305
3306The first parameter (``int ea_reason``) indicates the reason for External Abort.
3307Its value is one of ``ERROR_EA_*`` constants defined in ``ea_handle.h``.
3308
3309The second parameter (``uint64_t syndrome``) is the respective syndrome
3310presented to EL3 after having received the External Abort. Depending on the
3311nature of the abort (as can be inferred from the ``ea_reason`` parameter), this
3312can be the content of either ``ESR_EL3`` or ``DISR_EL1``.
3313
3314The third parameter (``void *cookie``) is unused for now. The fourth parameter
3315(``void *handle``) is a pointer to the preempted context. The fifth parameter
3316(``uint64_t flags``) indicates the preempted security state. These parameters
3317are received from the top-level exception handler.
3318
Manish Pandeyd419e222023-02-13 12:39:17 +00003319If ``RAS_FFH_SUPPORT`` is set to ``1``, the default implementation of this
Jeenu Viswambharanbf235bc2018-07-12 10:00:01 +01003320function iterates through RAS handlers registered by the platform. If any of the
3321RAS handlers resolve the External Abort, no further action is taken.
3322
Manish Pandeyd419e222023-02-13 12:39:17 +00003323If ``RAS_FFH_SUPPORT`` is set to ``0``, or if none of the platform RAS handlers
Jeenu Viswambharanbf235bc2018-07-12 10:00:01 +01003324could resolve the External Abort, the default implementation prints an error
3325message, and panics.
3326
3327Function : plat_handle_uncontainable_ea
3328~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3329
3330::
3331
3332 Argument : int
3333 Argument : uint64_t
3334 Return : void
3335
3336This function is invoked by the RAS framework when an External Abort of
3337Uncontainable type is received at EL3. Due to the critical nature of
3338Uncontainable errors, the intention of this function is to initiate orderly
3339shutdown of the system, and is not expected to return.
3340
3341This function must be implemented in assembly.
3342
3343The first and second parameters are the same as that of ``plat_ea_handler``.
3344
3345The default implementation of this function calls
3346``report_unhandled_exception``.
3347
3348Function : plat_handle_double_fault
3349~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3350
3351::
3352
3353 Argument : int
3354 Argument : uint64_t
3355 Return : void
3356
3357This function is invoked by the RAS framework when another External Abort is
3358received at EL3 while one is already being handled. I.e., a call to
3359``plat_ea_handler`` is outstanding. Due to its critical nature, the intention of
3360this function is to initiate orderly shutdown of the system, and is not expected
3361recover or return.
3362
3363This function must be implemented in assembly.
3364
3365The first and second parameters are the same as that of ``plat_ea_handler``.
3366
3367The default implementation of this function calls
3368``report_unhandled_exception``.
3369
3370Function : plat_handle_el3_ea
3371~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3372
3373::
3374
3375 Return : void
3376
3377This function is invoked when an External Abort is received while executing in
3378EL3. Due to its critical nature, the intention of this function is to initiate
3379orderly shutdown of the system, and is not expected recover or return.
3380
3381This function must be implemented in assembly.
3382
3383The default implementation of this function calls
3384``report_unhandled_exception``.
3385
Andre Przywarabdc76f12022-11-21 17:07:25 +00003386Function : plat_handle_rng_trap
3387~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3388
3389::
3390
3391 Argument : uint64_t
3392 Argument : cpu_context_t *
3393 Return : int
3394
3395This function is invoked by BL31's exception handler when there is a synchronous
3396system register trap caused by access to the RNDR or RNDRRS registers. It allows
3397platforms implementing ``FEAT_RNG_TRAP`` and enabling ``ENABLE_FEAT_RNG_TRAP`` to
3398emulate those system registers by returing back some entropy to the lower EL.
3399
3400The first parameter (``uint64_t esr_el3``) contains the content of the ESR_EL3
3401syndrome register, which encodes the instruction that was trapped. The interesting
3402information in there is the target register (``get_sysreg_iss_rt()``).
3403
3404The second parameter (``cpu_context_t *ctx``) represents the CPU state in the
3405lower exception level, at the time when the execution of the ``mrs`` instruction
3406was trapped. Its content can be changed, to put the entropy into the target
3407register.
3408
3409The return value indicates how to proceed:
3410
3411- When returning ``TRAP_RET_UNHANDLED`` (-1), the machine will panic.
3412- When returning ``TRAP_RET_REPEAT`` (0), the exception handler will return
3413 to the same instruction, so its execution will be repeated.
3414- When returning ``TRAP_RET_CONTINUE`` (1), the exception handler will return
3415 to the next instruction.
3416
3417This function needs to be implemented by a platform if it enables FEAT_RNG_TRAP.
3418
Varun Wadekar0a46eb12023-04-13 21:06:18 +01003419Function : plat_handle_impdef_trap
3420~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3421
3422::
3423
3424 Argument : uint64_t
3425 Argument : cpu_context_t *
3426 Return : int
3427
3428This function is invoked by BL31's exception handler when there is a synchronous
3429system register trap caused by access to the implementation defined registers.
3430It allows platforms enabling ``IMPDEF_SYSREG_TRAP`` to emulate those system
3431registers choosing to program bits of their choice.
3432
3433The first parameter (``uint64_t esr_el3``) contains the content of the ESR_EL3
3434syndrome register, which encodes the instruction that was trapped.
3435
3436The second parameter (``cpu_context_t *ctx``) represents the CPU state in the
3437lower exception level, at the time when the execution of the ``mrs`` instruction
3438was trapped.
3439
3440The return value indicates how to proceed:
3441
3442- When returning ``TRAP_RET_UNHANDLED`` (-1), the machine will panic.
3443- When returning ``TRAP_RET_REPEAT`` (0), the exception handler will return
3444 to the same instruction, so its execution will be repeated.
3445- When returning ``TRAP_RET_CONTINUE`` (1), the exception handler will return
3446 to the next instruction.
3447
3448This function needs to be implemented by a platform if it enables
3449IMPDEF_SYSREG_TRAP.
3450
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003451Build flags
3452-----------
3453
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003454There are some build flags which can be defined by the platform to control
3455inclusion or exclusion of certain BL stages from the FIP image. These flags
3456need to be defined in the platform makefile which will get included by the
3457build system.
3458
Sandrine Bailleux8d1a0552019-02-08 14:44:53 +01003459- **NEED_BL33**
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003460 By default, this flag is defined ``yes`` by the build system and ``BL33``
3461 build option should be supplied as a build option. The platform has the
3462 option of excluding the BL33 image in the ``fip`` image by defining this flag
3463 to ``no``. If any of the options ``EL3_PAYLOAD_BASE`` or ``PRELOADED_BL33_BASE``
3464 are used, this flag will be set to ``no`` automatically.
3465
Paul Beesley07f0a312019-05-16 13:33:18 +01003466Platform include paths
3467----------------------
3468
3469Platforms are allowed to add more include paths to be passed to the compiler.
3470The ``PLAT_INCLUDES`` variable is used for this purpose. This is needed in
3471particular for the file ``platform_def.h``.
3472
3473Example:
3474
3475.. code:: c
3476
3477 PLAT_INCLUDES += -Iinclude/plat/myplat/include
3478
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003479C Library
3480---------
3481
3482To avoid subtle toolchain behavioral dependencies, the header files provided
3483by the compiler are not used. The software is built with the ``-nostdinc`` flag
3484to ensure no headers are included from the toolchain inadvertently. Instead the
Dan Handley610e7e12018-03-01 18:44:00 +00003485required headers are included in the TF-A source tree. The library only
3486contains those C library definitions required by the local implementation. If
3487more functionality is required, the needed library functions will need to be
3488added to the local implementation.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003489
Antonio Nino Diazcf0f8052018-08-17 10:45:47 +01003490Some C headers have been obtained from `FreeBSD`_ and `SCC`_, while others have
Paul Beesleyf2ec7142019-10-04 16:17:46 +00003491been written specifically for TF-A. Some implementation files have been obtained
Antonio Nino Diazcf0f8052018-08-17 10:45:47 +01003492from `FreeBSD`_, others have been written specifically for TF-A as well. The
3493files can be found in ``include/lib/libc`` and ``lib/libc``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003494
Sandrine Bailleux6f0ecd72019-02-08 14:46:42 +01003495SCC can be found in http://www.simple-cc.org/. A copy of the `FreeBSD`_ sources
3496can be obtained from http://github.com/freebsd/freebsd.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003497
3498Storage abstraction layer
3499-------------------------
3500
Louis Mayencourtb5469002019-07-15 13:56:03 +01003501In order to improve platform independence and portability a storage abstraction
3502layer is used to load data from non-volatile platform storage. Currently
3503storage access is only required by BL1 and BL2 phases and performed inside the
3504``load_image()`` function in ``bl_common.c``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003505
Sandrine Bailleuxf17ddaa2023-02-08 14:07:29 +01003506.. uml:: resources/diagrams/plantuml/io_framework_usage_overview.puml
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003507
Dan Handley610e7e12018-03-01 18:44:00 +00003508It is mandatory to implement at least one storage driver. For the Arm
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003509development platforms the Firmware Image Package (FIP) driver is provided as
Paul Beesleyd2fcc4e2019-05-29 13:59:40 +01003510the default means to load data from storage (see :ref:`firmware_design_fip`).
3511The storage layer is described in the header file
3512``include/drivers/io/io_storage.h``. The implementation of the common library is
3513in ``drivers/io/io_storage.c`` and the driver files are located in
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003514``drivers/io/``.
3515
Sandrine Bailleuxf17ddaa2023-02-08 14:07:29 +01003516.. uml:: resources/diagrams/plantuml/io_arm_class_diagram.puml
Louis Mayencourtb5469002019-07-15 13:56:03 +01003517
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003518Each IO driver must provide ``io_dev_*`` structures, as described in
3519``drivers/io/io_driver.h``. These are returned via a mandatory registration
3520function that is called on platform initialization. The semi-hosting driver
3521implementation in ``io_semihosting.c`` can be used as an example.
3522
Louis Mayencourtb5469002019-07-15 13:56:03 +01003523Each platform should register devices and their drivers via the storage
3524abstraction layer. These drivers then need to be initialized by bootloader
3525phases as required in their respective ``blx_platform_setup()`` functions.
3526
Sandrine Bailleuxf17ddaa2023-02-08 14:07:29 +01003527.. uml:: resources/diagrams/plantuml/io_dev_registration.puml
Louis Mayencourtb5469002019-07-15 13:56:03 +01003528
3529The storage abstraction layer provides mechanisms (``io_dev_init()``) to
3530initialize storage devices before IO operations are called.
3531
Sandrine Bailleuxf17ddaa2023-02-08 14:07:29 +01003532.. uml:: resources/diagrams/plantuml/io_dev_init_and_check.puml
Louis Mayencourtb5469002019-07-15 13:56:03 +01003533
3534The basic operations supported by the layer
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003535include ``open()``, ``close()``, ``read()``, ``write()``, ``size()`` and ``seek()``.
3536Drivers do not have to implement all operations, but each platform must
3537provide at least one driver for a device capable of supporting generic
3538operations such as loading a bootloader image.
3539
3540The current implementation only allows for known images to be loaded by the
3541firmware. These images are specified by using their identifiers, as defined in
Antonio Nino Diaz645feb42019-02-13 14:07:38 +00003542``include/plat/common/common_def.h`` (or a separate header file included from
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003543there). The platform layer (``plat_get_image_source()``) then returns a reference
3544to a device and a driver-specific ``spec`` which will be understood by the driver
3545to allow access to the image data.
3546
3547The layer is designed in such a way that is it possible to chain drivers with
3548other drivers. For example, file-system drivers may be implemented on top of
3549physical block devices, both represented by IO devices with corresponding
3550drivers. In such a case, the file-system "binding" with the block device may
3551be deferred until the file-system device is initialised.
3552
3553The abstraction currently depends on structures being statically allocated
3554by the drivers and callers, as the system does not yet provide a means of
3555dynamically allocating memory. This may also have the affect of limiting the
3556amount of open resources per driver.
3557
Manish V Badarkhe93a61be2023-06-15 10:34:05 +01003558Measured Boot Platform Interface
3559--------------------------------
3560
3561Enabling the MEASURED_BOOT flag adds extra platform requirements. Please refer
3562to :ref:`Measured Boot Design` for more details.
3563
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003564--------------
3565
Chris Kay33bfc5e2023-02-14 11:30:04 +00003566*Copyright (c) 2013-2023, Arm Limited and Contributors. All rights reserved.*
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003567
Manish V Badarkhe9d24e9b2023-06-15 09:14:33 +01003568.. _PSCI: https://developer.arm.com/documentation/den0022/latest/
Dan Handley610e7e12018-03-01 18:44:00 +00003569.. _Arm Generic Interrupt Controller version 2.0 (GICv2): http://infocenter.arm.com/help/topic/com.arm.doc.ihi0048b/index.html
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003570.. _3.0 (GICv3): http://infocenter.arm.com/help/topic/com.arm.doc.ihi0069b/index.html
Paul Beesley2437ddc2019-02-08 16:43:05 +00003571.. _FreeBSD: https://www.freebsd.org
Antonio Nino Diazcf0f8052018-08-17 10:45:47 +01003572.. _SCC: http://www.simple-cc.org/
Lucian Paul-Trifub93037a2022-06-22 18:45:36 +01003573.. _DRTM: https://developer.arm.com/documentation/den0113/a