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Dan Handley610e7e12018-03-01 18:44:00 +00001Trusted Firmware-A Porting Guide
2================================
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003
4
5.. section-numbering::
6 :suffix: .
7
8.. contents::
9
10--------------
11
12Introduction
13------------
14
15Please note that this document has been updated for the new platform API
16as required by the PSCI v1.0 implementation. Please refer to the
17`Migration Guide`_ for the previous platform API.
18
Dan Handley610e7e12018-03-01 18:44:00 +000019Porting Trusted Firmware-A (TF-A) to a new platform involves making some
Douglas Raillardd7c21b72017-06-28 15:23:03 +010020mandatory and optional modifications for both the cold and warm boot paths.
21Modifications consist of:
22
23- Implementing a platform-specific function or variable,
24- Setting up the execution context in a certain way, or
25- Defining certain constants (for example #defines).
26
27The platform-specific functions and variables are declared in
28`include/plat/common/platform.h`_. The firmware provides a default implementation
29of variables and functions to fulfill the optional requirements. These
30implementations are all weakly defined; they are provided to ease the porting
31effort. Each platform port can override them with its own implementation if the
32default implementation is inadequate.
33
Dan Handley610e7e12018-03-01 18:44:00 +000034Platform ports that want to be aligned with standard Arm platforms (for example
Douglas Raillardd7c21b72017-06-28 15:23:03 +010035FVP and Juno) may also use `include/plat/arm/common/plat\_arm.h`_ and the
36corresponding source files in ``plat/arm/common/``. These provide standard
37implementations for some of the required platform porting functions. However,
38using these functions requires the platform port to implement additional
Dan Handley610e7e12018-03-01 18:44:00 +000039Arm standard platform porting functions. These additional functions are not
Douglas Raillardd7c21b72017-06-28 15:23:03 +010040documented here.
41
42Some modifications are common to all Boot Loader (BL) stages. Section 2
43discusses these in detail. The subsequent sections discuss the remaining
44modifications for each BL stage in detail.
45
Dan Handley610e7e12018-03-01 18:44:00 +000046This document should be read in conjunction with the TF-A `User Guide`_.
Douglas Raillardd7c21b72017-06-28 15:23:03 +010047
48Common modifications
49--------------------
50
51This section covers the modifications that should be made by the platform for
52each BL stage to correctly port the firmware stack. They are categorized as
53either mandatory or optional.
54
55Common mandatory modifications
56------------------------------
57
58A platform port must enable the Memory Management Unit (MMU) as well as the
59instruction and data caches for each BL stage. Setting up the translation
60tables is the responsibility of the platform port because memory maps differ
61across platforms. A memory translation library (see ``lib/xlat_tables/``) is
Sandrine Bailleux1861b7a2017-07-20 16:11:01 +010062provided to help in this setup.
63
64Note that although this library supports non-identity mappings, this is intended
65only for re-mapping peripheral physical addresses and allows platforms with high
66I/O addresses to reduce their virtual address space. All other addresses
67corresponding to code and data must currently use an identity mapping.
68
Dan Handley610e7e12018-03-01 18:44:00 +000069Also, the only translation granule size supported in TF-A is 4KB, as various
70parts of the code assume that is the case. It is not possible to switch to
7116 KB or 64 KB granule sizes at the moment.
Douglas Raillardd7c21b72017-06-28 15:23:03 +010072
Dan Handley610e7e12018-03-01 18:44:00 +000073In Arm standard platforms, each BL stage configures the MMU in the
Douglas Raillardd7c21b72017-06-28 15:23:03 +010074platform-specific architecture setup function, ``blX_plat_arch_setup()``, and uses
75an identity mapping for all addresses.
76
77If the build option ``USE_COHERENT_MEM`` is enabled, each platform can allocate a
78block of identity mapped secure memory with Device-nGnRE attributes aligned to
79page boundary (4K) for each BL stage. All sections which allocate coherent
80memory are grouped under ``coherent_ram``. For ex: Bakery locks are placed in a
81section identified by name ``bakery_lock`` inside ``coherent_ram`` so that its
82possible for the firmware to place variables in it using the following C code
83directive:
84
85::
86
87 __section("bakery_lock")
88
89Or alternatively the following assembler code directive:
90
91::
92
93 .section bakery_lock
94
95The ``coherent_ram`` section is a sum of all sections like ``bakery_lock`` which are
96used to allocate any data structures that are accessed both when a CPU is
97executing with its MMU and caches enabled, and when it's running with its MMU
98and caches disabled. Examples are given below.
99
100The following variables, functions and constants must be defined by the platform
101for the firmware to work correctly.
102
103File : platform\_def.h [mandatory]
104~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
105
106Each platform must ensure that a header file of this name is in the system
107include path with the following constants defined. This may require updating the
Dan Handley610e7e12018-03-01 18:44:00 +0000108list of ``PLAT_INCLUDES`` in the ``platform.mk`` file. In the Arm development
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100109platforms, this file is found in ``plat/arm/board/<plat_name>/include/``.
110
111Platform ports may optionally use the file `include/plat/common/common\_def.h`_,
112which provides typical values for some of the constants below. These values are
113likely to be suitable for all platform ports.
114
Dan Handley610e7e12018-03-01 18:44:00 +0000115Platform ports that want to be aligned with standard Arm platforms (for example
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100116FVP and Juno) may also use `include/plat/arm/common/arm\_def.h`_, which provides
117standard values for some of the constants below. However, this requires the
118platform port to define additional platform porting constants in
119``platform_def.h``. These additional constants are not documented here.
120
121- **#define : PLATFORM\_LINKER\_FORMAT**
122
123 Defines the linker format used by the platform, for example
124 ``elf64-littleaarch64``.
125
126- **#define : PLATFORM\_LINKER\_ARCH**
127
128 Defines the processor architecture for the linker by the platform, for
129 example ``aarch64``.
130
131- **#define : PLATFORM\_STACK\_SIZE**
132
133 Defines the normal stack memory available to each CPU. This constant is used
134 by `plat/common/aarch64/platform\_mp\_stack.S`_ and
135 `plat/common/aarch64/platform\_up\_stack.S`_.
136
137- **define : CACHE\_WRITEBACK\_GRANULE**
138
139 Defines the size in bits of the largest cache line across all the cache
140 levels in the platform.
141
142- **#define : FIRMWARE\_WELCOME\_STR**
143
144 Defines the character string printed by BL1 upon entry into the ``bl1_main()``
145 function.
146
147- **#define : PLATFORM\_CORE\_COUNT**
148
149 Defines the total number of CPUs implemented by the platform across all
150 clusters in the system.
151
152- **#define : PLAT\_NUM\_PWR\_DOMAINS**
153
154 Defines the total number of nodes in the power domain topology
155 tree at all the power domain levels used by the platform.
156 This macro is used by the PSCI implementation to allocate
157 data structures to represent power domain topology.
158
159- **#define : PLAT\_MAX\_PWR\_LVL**
160
161 Defines the maximum power domain level that the power management operations
162 should apply to. More often, but not always, the power domain level
163 corresponds to affinity level. This macro allows the PSCI implementation
164 to know the highest power domain level that it should consider for power
165 management operations in the system that the platform implements. For
166 example, the Base AEM FVP implements two clusters with a configurable
167 number of CPUs and it reports the maximum power domain level as 1.
168
169- **#define : PLAT\_MAX\_OFF\_STATE**
170
171 Defines the local power state corresponding to the deepest power down
172 possible at every power domain level in the platform. The local power
173 states for each level may be sparsely allocated between 0 and this value
174 with 0 being reserved for the RUN state. The PSCI implementation uses this
175 value to initialize the local power states of the power domain nodes and
176 to specify the requested power state for a PSCI\_CPU\_OFF call.
177
178- **#define : PLAT\_MAX\_RET\_STATE**
179
180 Defines the local power state corresponding to the deepest retention state
181 possible at every power domain level in the platform. This macro should be
182 a value less than PLAT\_MAX\_OFF\_STATE and greater than 0. It is used by the
183 PSCI implementation to distinguish between retention and power down local
184 power states within PSCI\_CPU\_SUSPEND call.
185
186- **#define : PLAT\_MAX\_PWR\_LVL\_STATES**
187
188 Defines the maximum number of local power states per power domain level
189 that the platform supports. The default value of this macro is 2 since
190 most platforms just support a maximum of two local power states at each
191 power domain level (power-down and retention). If the platform needs to
192 account for more local power states, then it must redefine this macro.
193
194 Currently, this macro is used by the Generic PSCI implementation to size
195 the array used for PSCI\_STAT\_COUNT/RESIDENCY accounting.
196
197- **#define : BL1\_RO\_BASE**
198
199 Defines the base address in secure ROM where BL1 originally lives. Must be
200 aligned on a page-size boundary.
201
202- **#define : BL1\_RO\_LIMIT**
203
204 Defines the maximum address in secure ROM that BL1's actual content (i.e.
205 excluding any data section allocated at runtime) can occupy.
206
207- **#define : BL1\_RW\_BASE**
208
209 Defines the base address in secure RAM where BL1's read-write data will live
210 at runtime. Must be aligned on a page-size boundary.
211
212- **#define : BL1\_RW\_LIMIT**
213
214 Defines the maximum address in secure RAM that BL1's read-write data can
215 occupy at runtime.
216
217- **#define : BL2\_BASE**
218
219 Defines the base address in secure RAM where BL1 loads the BL2 binary image.
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000220 Must be aligned on a page-size boundary. This constant is not applicable
221 when BL2_IN_XIP_MEM is set to '1'.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100222
223- **#define : BL2\_LIMIT**
224
225 Defines the maximum address in secure RAM that the BL2 image can occupy.
Jiafei Pan43a7bf42018-03-21 07:20:09 +0000226 This constant is not applicable when BL2_IN_XIP_MEM is set to '1'.
227
228- **#define : BL2\_RO\_BASE**
229
230 Defines the base address in secure XIP memory where BL2 RO section originally
231 lives. Must be aligned on a page-size boundary. This constant is only needed
232 when BL2_IN_XIP_MEM is set to '1'.
233
234- **#define : BL2\_RO\_LIMIT**
235
236 Defines the maximum address in secure XIP memory that BL2's actual content
237 (i.e. excluding any data section allocated at runtime) can occupy. This
238 constant is only needed when BL2_IN_XIP_MEM is set to '1'.
239
240- **#define : BL2\_RW\_BASE**
241
242 Defines the base address in secure RAM where BL2's read-write data will live
243 at runtime. Must be aligned on a page-size boundary. This constant is only
244 needed when BL2_IN_XIP_MEM is set to '1'.
245
246- **#define : BL2\_RW\_LIMIT**
247
248 Defines the maximum address in secure RAM that BL2's read-write data can
249 occupy at runtime. This constant is only needed when BL2_IN_XIP_MEM is set
250 to '1'.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100251
252- **#define : BL31\_BASE**
253
254 Defines the base address in secure RAM where BL2 loads the BL31 binary
255 image. Must be aligned on a page-size boundary.
256
257- **#define : BL31\_LIMIT**
258
259 Defines the maximum address in secure RAM that the BL31 image can occupy.
260
261For every image, the platform must define individual identifiers that will be
262used by BL1 or BL2 to load the corresponding image into memory from non-volatile
263storage. For the sake of performance, integer numbers will be used as
264identifiers. The platform will use those identifiers to return the relevant
265information about the image to be loaded (file handler, load address,
266authentication information, etc.). The following image identifiers are
267mandatory:
268
269- **#define : BL2\_IMAGE\_ID**
270
271 BL2 image identifier, used by BL1 to load BL2.
272
273- **#define : BL31\_IMAGE\_ID**
274
275 BL31 image identifier, used by BL2 to load BL31.
276
277- **#define : BL33\_IMAGE\_ID**
278
279 BL33 image identifier, used by BL2 to load BL33.
280
281If Trusted Board Boot is enabled, the following certificate identifiers must
282also be defined:
283
284- **#define : TRUSTED\_BOOT\_FW\_CERT\_ID**
285
286 BL2 content certificate identifier, used by BL1 to load the BL2 content
287 certificate.
288
289- **#define : TRUSTED\_KEY\_CERT\_ID**
290
291 Trusted key certificate identifier, used by BL2 to load the trusted key
292 certificate.
293
294- **#define : SOC\_FW\_KEY\_CERT\_ID**
295
296 BL31 key certificate identifier, used by BL2 to load the BL31 key
297 certificate.
298
299- **#define : SOC\_FW\_CONTENT\_CERT\_ID**
300
301 BL31 content certificate identifier, used by BL2 to load the BL31 content
302 certificate.
303
304- **#define : NON\_TRUSTED\_FW\_KEY\_CERT\_ID**
305
306 BL33 key certificate identifier, used by BL2 to load the BL33 key
307 certificate.
308
309- **#define : NON\_TRUSTED\_FW\_CONTENT\_CERT\_ID**
310
311 BL33 content certificate identifier, used by BL2 to load the BL33 content
312 certificate.
313
314- **#define : FWU\_CERT\_ID**
315
316 Firmware Update (FWU) certificate identifier, used by NS\_BL1U to load the
317 FWU content certificate.
318
319- **#define : PLAT\_CRYPTOCELL\_BASE**
320
Dan Handley610e7e12018-03-01 18:44:00 +0000321 This defines the base address of Arm® TrustZone® CryptoCell and must be
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100322 defined if CryptoCell crypto driver is used for Trusted Board Boot. For
Dan Handley610e7e12018-03-01 18:44:00 +0000323 capable Arm platforms, this driver is used if ``ARM_CRYPTOCELL_INTEG`` is
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100324 set.
325
326If the AP Firmware Updater Configuration image, BL2U is used, the following
327must also be defined:
328
329- **#define : BL2U\_BASE**
330
331 Defines the base address in secure memory where BL1 copies the BL2U binary
332 image. Must be aligned on a page-size boundary.
333
334- **#define : BL2U\_LIMIT**
335
336 Defines the maximum address in secure memory that the BL2U image can occupy.
337
338- **#define : BL2U\_IMAGE\_ID**
339
340 BL2U image identifier, used by BL1 to fetch an image descriptor
341 corresponding to BL2U.
342
343If the SCP Firmware Update Configuration Image, SCP\_BL2U is used, the following
344must also be defined:
345
346- **#define : SCP\_BL2U\_IMAGE\_ID**
347
348 SCP\_BL2U image identifier, used by BL1 to fetch an image descriptor
349 corresponding to SCP\_BL2U.
Dan Handley610e7e12018-03-01 18:44:00 +0000350 NOTE: TF-A does not provide source code for this image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100351
352If the Non-Secure Firmware Updater ROM, NS\_BL1U is used, the following must
353also be defined:
354
355- **#define : NS\_BL1U\_BASE**
356
357 Defines the base address in non-secure ROM where NS\_BL1U executes.
358 Must be aligned on a page-size boundary.
Dan Handley610e7e12018-03-01 18:44:00 +0000359 NOTE: TF-A does not provide source code for this image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100360
361- **#define : NS\_BL1U\_IMAGE\_ID**
362
363 NS\_BL1U image identifier, used by BL1 to fetch an image descriptor
364 corresponding to NS\_BL1U.
365
366If the Non-Secure Firmware Updater, NS\_BL2U is used, the following must also
367be defined:
368
369- **#define : NS\_BL2U\_BASE**
370
371 Defines the base address in non-secure memory where NS\_BL2U executes.
372 Must be aligned on a page-size boundary.
Dan Handley610e7e12018-03-01 18:44:00 +0000373 NOTE: TF-A does not provide source code for this image.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100374
375- **#define : NS\_BL2U\_IMAGE\_ID**
376
377 NS\_BL2U image identifier, used by BL1 to fetch an image descriptor
378 corresponding to NS\_BL2U.
379
380For the the Firmware update capability of TRUSTED BOARD BOOT, the following
381macros may also be defined:
382
383- **#define : PLAT\_FWU\_MAX\_SIMULTANEOUS\_IMAGES**
384
385 Total number of images that can be loaded simultaneously. If the platform
386 doesn't specify any value, it defaults to 10.
387
388If a SCP\_BL2 image is supported by the platform, the following constants must
389also be defined:
390
391- **#define : SCP\_BL2\_IMAGE\_ID**
392
393 SCP\_BL2 image identifier, used by BL2 to load SCP\_BL2 into secure memory
394 from platform storage before being transfered to the SCP.
395
396- **#define : SCP\_FW\_KEY\_CERT\_ID**
397
398 SCP\_BL2 key certificate identifier, used by BL2 to load the SCP\_BL2 key
399 certificate (mandatory when Trusted Board Boot is enabled).
400
401- **#define : SCP\_FW\_CONTENT\_CERT\_ID**
402
403 SCP\_BL2 content certificate identifier, used by BL2 to load the SCP\_BL2
404 content certificate (mandatory when Trusted Board Boot is enabled).
405
406If a BL32 image is supported by the platform, the following constants must
407also be defined:
408
409- **#define : BL32\_IMAGE\_ID**
410
411 BL32 image identifier, used by BL2 to load BL32.
412
413- **#define : TRUSTED\_OS\_FW\_KEY\_CERT\_ID**
414
415 BL32 key certificate identifier, used by BL2 to load the BL32 key
416 certificate (mandatory when Trusted Board Boot is enabled).
417
418- **#define : TRUSTED\_OS\_FW\_CONTENT\_CERT\_ID**
419
420 BL32 content certificate identifier, used by BL2 to load the BL32 content
421 certificate (mandatory when Trusted Board Boot is enabled).
422
423- **#define : BL32\_BASE**
424
425 Defines the base address in secure memory where BL2 loads the BL32 binary
426 image. Must be aligned on a page-size boundary.
427
428- **#define : BL32\_LIMIT**
429
430 Defines the maximum address that the BL32 image can occupy.
431
432If the Test Secure-EL1 Payload (TSP) instantiation of BL32 is supported by the
433platform, the following constants must also be defined:
434
435- **#define : TSP\_SEC\_MEM\_BASE**
436
437 Defines the base address of the secure memory used by the TSP image on the
438 platform. This must be at the same address or below ``BL32_BASE``.
439
440- **#define : TSP\_SEC\_MEM\_SIZE**
441
442 Defines the size of the secure memory used by the BL32 image on the
443 platform. ``TSP_SEC_MEM_BASE`` and ``TSP_SEC_MEM_SIZE`` must fully accomodate
444 the memory required by the BL32 image, defined by ``BL32_BASE`` and
445 ``BL32_LIMIT``.
446
447- **#define : TSP\_IRQ\_SEC\_PHY\_TIMER**
448
449 Defines the ID of the secure physical generic timer interrupt used by the
450 TSP's interrupt handling code.
451
452If the platform port uses the translation table library code, the following
453constants must also be defined:
454
455- **#define : PLAT\_XLAT\_TABLES\_DYNAMIC**
456
457 Optional flag that can be set per-image to enable the dynamic allocation of
458 regions even when the MMU is enabled. If not defined, only static
459 functionality will be available, if defined and set to 1 it will also
460 include the dynamic functionality.
461
462- **#define : MAX\_XLAT\_TABLES**
463
464 Defines the maximum number of translation tables that are allocated by the
465 translation table library code. To minimize the amount of runtime memory
466 used, choose the smallest value needed to map the required virtual addresses
467 for each BL stage. If ``PLAT_XLAT_TABLES_DYNAMIC`` flag is enabled for a BL
468 image, ``MAX_XLAT_TABLES`` must be defined to accommodate the dynamic regions
469 as well.
470
471- **#define : MAX\_MMAP\_REGIONS**
472
473 Defines the maximum number of regions that are allocated by the translation
474 table library code. A region consists of physical base address, virtual base
475 address, size and attributes (Device/Memory, RO/RW, Secure/Non-Secure), as
476 defined in the ``mmap_region_t`` structure. The platform defines the regions
477 that should be mapped. Then, the translation table library will create the
478 corresponding tables and descriptors at runtime. To minimize the amount of
479 runtime memory used, choose the smallest value needed to register the
480 required regions for each BL stage. If ``PLAT_XLAT_TABLES_DYNAMIC`` flag is
481 enabled for a BL image, ``MAX_MMAP_REGIONS`` must be defined to accommodate
482 the dynamic regions as well.
483
484- **#define : ADDR\_SPACE\_SIZE**
485
486 Defines the total size of the address space in bytes. For example, for a 32
David Cunadoc1503122018-02-16 21:12:58 +0000487 bit address space, this value should be ``(1ULL << 32)``. This definition is
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100488 now deprecated, platforms should use ``PLAT_PHY_ADDR_SPACE_SIZE`` and
489 ``PLAT_VIRT_ADDR_SPACE_SIZE`` instead.
490
491- **#define : PLAT\_VIRT\_ADDR\_SPACE\_SIZE**
492
493 Defines the total size of the virtual address space in bytes. For example,
David Cunadoc1503122018-02-16 21:12:58 +0000494 for a 32 bit virtual address space, this value should be ``(1ULL << 32)``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100495
496- **#define : PLAT\_PHY\_ADDR\_SPACE\_SIZE**
497
498 Defines the total size of the physical address space in bytes. For example,
David Cunadoc1503122018-02-16 21:12:58 +0000499 for a 32 bit physical address space, this value should be ``(1ULL << 32)``.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100500
501If the platform port uses the IO storage framework, the following constants
502must also be defined:
503
504- **#define : MAX\_IO\_DEVICES**
505
506 Defines the maximum number of registered IO devices. Attempting to register
507 more devices than this value using ``io_register_device()`` will fail with
508 -ENOMEM.
509
510- **#define : MAX\_IO\_HANDLES**
511
512 Defines the maximum number of open IO handles. Attempting to open more IO
513 entities than this value using ``io_open()`` will fail with -ENOMEM.
514
515- **#define : MAX\_IO\_BLOCK\_DEVICES**
516
517 Defines the maximum number of registered IO block devices. Attempting to
518 register more devices this value using ``io_dev_open()`` will fail
519 with -ENOMEM. MAX\_IO\_BLOCK\_DEVICES should be less than MAX\_IO\_DEVICES.
520 With this macro, multiple block devices could be supported at the same
521 time.
522
523If the platform needs to allocate data within the per-cpu data framework in
524BL31, it should define the following macro. Currently this is only required if
525the platform decides not to use the coherent memory section by undefining the
526``USE_COHERENT_MEM`` build flag. In this case, the framework allocates the
527required memory within the the per-cpu data to minimize wastage.
528
529- **#define : PLAT\_PCPU\_DATA\_SIZE**
530
531 Defines the memory (in bytes) to be reserved within the per-cpu data
532 structure for use by the platform layer.
533
534The following constants are optional. They should be defined when the platform
Dan Handley610e7e12018-03-01 18:44:00 +0000535memory layout implies some image overlaying like in Arm standard platforms.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100536
537- **#define : BL31\_PROGBITS\_LIMIT**
538
539 Defines the maximum address in secure RAM that the BL31's progbits sections
540 can occupy.
541
542- **#define : TSP\_PROGBITS\_LIMIT**
543
544 Defines the maximum address that the TSP's progbits sections can occupy.
545
546If the platform port uses the PL061 GPIO driver, the following constant may
547optionally be defined:
548
549- **PLAT\_PL061\_MAX\_GPIOS**
550 Maximum number of GPIOs required by the platform. This allows control how
551 much memory is allocated for PL061 GPIO controllers. The default value is
552
553 #. $(eval $(call add\_define,PLAT\_PL061\_MAX\_GPIOS))
554
555If the platform port uses the partition driver, the following constant may
556optionally be defined:
557
558- **PLAT\_PARTITION\_MAX\_ENTRIES**
559 Maximum number of partition entries required by the platform. This allows
560 control how much memory is allocated for partition entries. The default
561 value is 128.
562 `For example, define the build flag in platform.mk`_:
563 PLAT\_PARTITION\_MAX\_ENTRIES := 12
564 $(eval $(call add\_define,PLAT\_PARTITION\_MAX\_ENTRIES))
565
566The following constant is optional. It should be defined to override the default
567behaviour of the ``assert()`` function (for example, to save memory).
568
569- **PLAT\_LOG\_LEVEL\_ASSERT**
570 If ``PLAT_LOG_LEVEL_ASSERT`` is higher or equal than ``LOG_LEVEL_VERBOSE``,
571 ``assert()`` prints the name of the file, the line number and the asserted
572 expression. Else if it is higher than ``LOG_LEVEL_INFO``, it prints the file
573 name and the line number. Else if it is lower than ``LOG_LEVEL_INFO``, it
574 doesn't print anything to the console. If ``PLAT_LOG_LEVEL_ASSERT`` isn't
575 defined, it defaults to ``LOG_LEVEL``.
576
Dimitris Papastamos60346db2017-12-13 10:54:37 +0000577If the platform port uses the Activity Monitor Unit, the following constants
578may be defined:
579
580- **PLAT\_AMU\_GROUP1\_COUNTERS\_MASK**
581 This mask reflects the set of group counters that should be enabled. The
582 maximum number of group 1 counters supported by AMUv1 is 16 so the mask
583 can be at most 0xffff. If the platform does not define this mask, no group 1
584 counters are enabled. If the platform defines this mask, the following
585 constant needs to also be defined.
586
587- **PLAT\_AMU\_GROUP1\_NR\_COUNTERS**
588 This value is used to allocate an array to save and restore the counters
589 specified by ``PLAT_AMU_GROUP1_COUNTERS_MASK`` on CPU suspend.
590 This value should be equal to the highest bit position set in the
591 mask, plus 1. The maximum number of group 1 counters in AMUv1 is 16.
592
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100593File : plat\_macros.S [mandatory]
594~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
595
596Each platform must ensure a file of this name is in the system include path with
Dan Handley610e7e12018-03-01 18:44:00 +0000597the following macro defined. In the Arm development platforms, this file is
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100598found in ``plat/arm/board/<plat_name>/include/plat_macros.S``.
599
600- **Macro : plat\_crash\_print\_regs**
601
602 This macro allows the crash reporting routine to print relevant platform
603 registers in case of an unhandled exception in BL31. This aids in debugging
604 and this macro can be defined to be empty in case register reporting is not
605 desired.
606
607 For instance, GIC or interconnect registers may be helpful for
608 troubleshooting.
609
610Handling Reset
611--------------
612
613BL1 by default implements the reset vector where execution starts from a cold
614or warm boot. BL31 can be optionally set as a reset vector using the
615``RESET_TO_BL31`` make variable.
616
617For each CPU, the reset vector code is responsible for the following tasks:
618
619#. Distinguishing between a cold boot and a warm boot.
620
621#. In the case of a cold boot and the CPU being a secondary CPU, ensuring that
622 the CPU is placed in a platform-specific state until the primary CPU
623 performs the necessary steps to remove it from this state.
624
625#. In the case of a warm boot, ensuring that the CPU jumps to a platform-
626 specific address in the BL31 image in the same processor mode as it was
627 when released from reset.
628
629The following functions need to be implemented by the platform port to enable
630reset vector code to perform the above tasks.
631
632Function : plat\_get\_my\_entrypoint() [mandatory when PROGRAMMABLE\_RESET\_ADDRESS == 0]
633~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
634
635::
636
637 Argument : void
638 Return : uintptr_t
639
640This function is called with the MMU and caches disabled
641(``SCTLR_EL3.M`` = 0 and ``SCTLR_EL3.C`` = 0). The function is responsible for
642distinguishing between a warm and cold reset for the current CPU using
643platform-specific means. If it's a warm reset, then it returns the warm
644reset entrypoint point provided to ``plat_setup_psci_ops()`` during
645BL31 initialization. If it's a cold reset then this function must return zero.
646
647This function does not follow the Procedure Call Standard used by the
Dan Handley610e7e12018-03-01 18:44:00 +0000648Application Binary Interface for the Arm 64-bit architecture. The caller should
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100649not assume that callee saved registers are preserved across a call to this
650function.
651
652This function fulfills requirement 1 and 3 listed above.
653
654Note that for platforms that support programming the reset address, it is
655expected that a CPU will start executing code directly at the right address,
656both on a cold and warm reset. In this case, there is no need to identify the
657type of reset nor to query the warm reset entrypoint. Therefore, implementing
658this function is not required on such platforms.
659
660Function : plat\_secondary\_cold\_boot\_setup() [mandatory when COLD\_BOOT\_SINGLE\_CPU == 0]
661~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
662
663::
664
665 Argument : void
666
667This function is called with the MMU and data caches disabled. It is responsible
668for placing the executing secondary CPU in a platform-specific state until the
669primary CPU performs the necessary actions to bring it out of that state and
670allow entry into the OS. This function must not return.
671
Dan Handley610e7e12018-03-01 18:44:00 +0000672In the Arm FVP port, when using the normal boot flow, each secondary CPU powers
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100673itself off. The primary CPU is responsible for powering up the secondary CPUs
674when normal world software requires them. When booting an EL3 payload instead,
675they stay powered on and are put in a holding pen until their mailbox gets
676populated.
677
678This function fulfills requirement 2 above.
679
680Note that for platforms that can't release secondary CPUs out of reset, only the
681primary CPU will execute the cold boot code. Therefore, implementing this
682function is not required on such platforms.
683
684Function : plat\_is\_my\_cpu\_primary() [mandatory when COLD\_BOOT\_SINGLE\_CPU == 0]
685~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
686
687::
688
689 Argument : void
690 Return : unsigned int
691
692This function identifies whether the current CPU is the primary CPU or a
693secondary CPU. A return value of zero indicates that the CPU is not the
694primary CPU, while a non-zero return value indicates that the CPU is the
695primary CPU.
696
697Note that for platforms that can't release secondary CPUs out of reset, only the
698primary CPU will execute the cold boot code. Therefore, there is no need to
699distinguish between primary and secondary CPUs and implementing this function is
700not required.
701
702Function : platform\_mem\_init() [mandatory]
703~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
704
705::
706
707 Argument : void
708 Return : void
709
710This function is called before any access to data is made by the firmware, in
711order to carry out any essential memory initialization.
712
713Function: plat\_get\_rotpk\_info()
714~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
715
716::
717
718 Argument : void *, void **, unsigned int *, unsigned int *
719 Return : int
720
721This function is mandatory when Trusted Board Boot is enabled. It returns a
722pointer to the ROTPK stored in the platform (or a hash of it) and its length.
723The ROTPK must be encoded in DER format according to the following ASN.1
724structure:
725
726::
727
728 AlgorithmIdentifier ::= SEQUENCE {
729 algorithm OBJECT IDENTIFIER,
730 parameters ANY DEFINED BY algorithm OPTIONAL
731 }
732
733 SubjectPublicKeyInfo ::= SEQUENCE {
734 algorithm AlgorithmIdentifier,
735 subjectPublicKey BIT STRING
736 }
737
738In case the function returns a hash of the key:
739
740::
741
742 DigestInfo ::= SEQUENCE {
743 digestAlgorithm AlgorithmIdentifier,
744 digest OCTET STRING
745 }
746
747The function returns 0 on success. Any other value is treated as error by the
748Trusted Board Boot. The function also reports extra information related
749to the ROTPK in the flags parameter:
750
751::
752
753 ROTPK_IS_HASH : Indicates that the ROTPK returned by the platform is a
754 hash.
755 ROTPK_NOT_DEPLOYED : This allows the platform to skip certificate ROTPK
756 verification while the platform ROTPK is not deployed.
757 When this flag is set, the function does not need to
758 return a platform ROTPK, and the authentication
759 framework uses the ROTPK in the certificate without
760 verifying it against the platform value. This flag
761 must not be used in a deployed production environment.
762
763Function: plat\_get\_nv\_ctr()
764~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
765
766::
767
768 Argument : void *, unsigned int *
769 Return : int
770
771This function is mandatory when Trusted Board Boot is enabled. It returns the
772non-volatile counter value stored in the platform in the second argument. The
773cookie in the first argument may be used to select the counter in case the
774platform provides more than one (for example, on platforms that use the default
775TBBR CoT, the cookie will correspond to the OID values defined in
776TRUSTED\_FW\_NVCOUNTER\_OID or NON\_TRUSTED\_FW\_NVCOUNTER\_OID).
777
778The function returns 0 on success. Any other value means the counter value could
779not be retrieved from the platform.
780
781Function: plat\_set\_nv\_ctr()
782~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
783
784::
785
786 Argument : void *, unsigned int
787 Return : int
788
789This function is mandatory when Trusted Board Boot is enabled. It sets a new
790counter value in the platform. The cookie in the first argument may be used to
791select the counter (as explained in plat\_get\_nv\_ctr()). The second argument is
792the updated counter value to be written to the NV counter.
793
794The function returns 0 on success. Any other value means the counter value could
795not be updated.
796
797Function: plat\_set\_nv\_ctr2()
798~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
799
800::
801
802 Argument : void *, const auth_img_desc_t *, unsigned int
803 Return : int
804
805This function is optional when Trusted Board Boot is enabled. If this
806interface is defined, then ``plat_set_nv_ctr()`` need not be defined. The
807first argument passed is a cookie and is typically used to
808differentiate between a Non Trusted NV Counter and a Trusted NV
809Counter. The second argument is a pointer to an authentication image
810descriptor and may be used to decide if the counter is allowed to be
811updated or not. The third argument is the updated counter value to
812be written to the NV counter.
813
814The function returns 0 on success. Any other value means the counter value
815either could not be updated or the authentication image descriptor indicates
816that it is not allowed to be updated.
817
818Common mandatory function modifications
819---------------------------------------
820
821The following functions are mandatory functions which need to be implemented
822by the platform port.
823
824Function : plat\_my\_core\_pos()
825~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
826
827::
828
829 Argument : void
830 Return : unsigned int
831
832This funtion returns the index of the calling CPU which is used as a
833CPU-specific linear index into blocks of memory (for example while allocating
834per-CPU stacks). This function will be invoked very early in the
835initialization sequence which mandates that this function should be
836implemented in assembly and should not rely on the avalability of a C
837runtime environment. This function can clobber x0 - x8 and must preserve
838x9 - x29.
839
840This function plays a crucial role in the power domain topology framework in
841PSCI and details of this can be found in `Power Domain Topology Design`_.
842
843Function : plat\_core\_pos\_by\_mpidr()
844~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
845
846::
847
848 Argument : u_register_t
849 Return : int
850
851This function validates the ``MPIDR`` of a CPU and converts it to an index,
852which can be used as a CPU-specific linear index into blocks of memory. In
853case the ``MPIDR`` is invalid, this function returns -1. This function will only
854be invoked by BL31 after the power domain topology is initialized and can
Dan Handley610e7e12018-03-01 18:44:00 +0000855utilize the C runtime environment. For further details about how TF-A
856represents the power domain topology and how this relates to the linear CPU
857index, please refer `Power Domain Topology Design`_.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100858
859Common optional modifications
860-----------------------------
861
862The following are helper functions implemented by the firmware that perform
863common platform-specific tasks. A platform may choose to override these
864definitions.
865
866Function : plat\_set\_my\_stack()
867~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
868
869::
870
871 Argument : void
872 Return : void
873
874This function sets the current stack pointer to the normal memory stack that
875has been allocated for the current CPU. For BL images that only require a
876stack for the primary CPU, the UP version of the function is used. The size
877of the stack allocated to each CPU is specified by the platform defined
878constant ``PLATFORM_STACK_SIZE``.
879
880Common implementations of this function for the UP and MP BL images are
881provided in `plat/common/aarch64/platform\_up\_stack.S`_ and
882`plat/common/aarch64/platform\_mp\_stack.S`_
883
884Function : plat\_get\_my\_stack()
885~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
886
887::
888
889 Argument : void
890 Return : uintptr_t
891
892This function returns the base address of the normal memory stack that
893has been allocated for the current CPU. For BL images that only require a
894stack for the primary CPU, the UP version of the function is used. The size
895of the stack allocated to each CPU is specified by the platform defined
896constant ``PLATFORM_STACK_SIZE``.
897
898Common implementations of this function for the UP and MP BL images are
899provided in `plat/common/aarch64/platform\_up\_stack.S`_ and
900`plat/common/aarch64/platform\_mp\_stack.S`_
901
902Function : plat\_report\_exception()
903~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
904
905::
906
907 Argument : unsigned int
908 Return : void
909
910A platform may need to report various information about its status when an
911exception is taken, for example the current exception level, the CPU security
912state (secure/non-secure), the exception type, and so on. This function is
913called in the following circumstances:
914
915- In BL1, whenever an exception is taken.
916- In BL2, whenever an exception is taken.
917
918The default implementation doesn't do anything, to avoid making assumptions
919about the way the platform displays its status information.
920
921For AArch64, this function receives the exception type as its argument.
922Possible values for exceptions types are listed in the
923`include/common/bl\_common.h`_ header file. Note that these constants are not
Dan Handley610e7e12018-03-01 18:44:00 +0000924related to any architectural exception code; they are just a TF-A convention.
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100925
926For AArch32, this function receives the exception mode as its argument.
927Possible values for exception modes are listed in the
928`include/lib/aarch32/arch.h`_ header file.
929
930Function : plat\_reset\_handler()
931~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
932
933::
934
935 Argument : void
936 Return : void
937
938A platform may need to do additional initialization after reset. This function
939allows the platform to do the platform specific intializations. Platform
940specific errata workarounds could also be implemented here. The api should
941preserve the values of callee saved registers x19 to x29.
942
943The default implementation doesn't do anything. If a platform needs to override
944the default implementation, refer to the `Firmware Design`_ for general
945guidelines.
946
947Function : plat\_disable\_acp()
948~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
949
950::
951
952 Argument : void
953 Return : void
954
955This api allows a platform to disable the Accelerator Coherency Port (if
956present) during a cluster power down sequence. The default weak implementation
957doesn't do anything. Since this api is called during the power down sequence,
958it has restrictions for stack usage and it can use the registers x0 - x17 as
959scratch registers. It should preserve the value in x18 register as it is used
960by the caller to store the return address.
961
962Function : plat\_error\_handler()
963~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
964
965::
966
967 Argument : int
968 Return : void
969
970This API is called when the generic code encounters an error situation from
971which it cannot continue. It allows the platform to perform error reporting or
972recovery actions (for example, reset the system). This function must not return.
973
974The parameter indicates the type of error using standard codes from ``errno.h``.
975Possible errors reported by the generic code are:
976
977- ``-EAUTH``: a certificate or image could not be authenticated (when Trusted
978 Board Boot is enabled)
979- ``-ENOENT``: the requested image or certificate could not be found or an IO
980 error was detected
Dan Handley610e7e12018-03-01 18:44:00 +0000981- ``-ENOMEM``: resources exhausted. TF-A does not use dynamic memory, so this
982 error is usually an indication of an incorrect array size
Douglas Raillardd7c21b72017-06-28 15:23:03 +0100983
984The default implementation simply spins.
985
986Function : plat\_panic\_handler()
987~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
988
989::
990
991 Argument : void
992 Return : void
993
994This API is called when the generic code encounters an unexpected error
995situation from which it cannot recover. This function must not return,
996and must be implemented in assembly because it may be called before the C
997environment is initialized.
998
999Note: The address from where it was called is stored in x30 (Link Register).
1000The default implementation simply spins.
1001
1002Function : plat\_get\_bl\_image\_load\_info()
1003~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1004
1005::
1006
1007 Argument : void
1008 Return : bl_load_info_t *
1009
1010This function returns pointer to the list of images that the platform has
1011populated to load. This function is currently invoked in BL2 to load the
1012BL3xx images, when LOAD\_IMAGE\_V2 is enabled.
1013
1014Function : plat\_get\_next\_bl\_params()
1015~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1016
1017::
1018
1019 Argument : void
1020 Return : bl_params_t *
1021
1022This function returns a pointer to the shared memory that the platform has
Dan Handley610e7e12018-03-01 18:44:00 +00001023kept aside to pass TF-A related information that next BL image needs. This
1024function is currently invoked in BL2 to pass this information to the next BL
1025image, when LOAD\_IMAGE\_V2 is enabled.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001026
1027Function : plat\_get\_stack\_protector\_canary()
1028~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1029
1030::
1031
1032 Argument : void
1033 Return : u_register_t
1034
1035This function returns a random value that is used to initialize the canary used
1036when the stack protector is enabled with ENABLE\_STACK\_PROTECTOR. A predictable
1037value will weaken the protection as the attacker could easily write the right
1038value as part of the attack most of the time. Therefore, it should return a
1039true random number.
1040
1041Note: For the protection to be effective, the global data need to be placed at
1042a lower address than the stack bases. Failure to do so would allow an attacker
1043to overwrite the canary as part of the stack buffer overflow attack.
1044
1045Function : plat\_flush\_next\_bl\_params()
1046~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1047
1048::
1049
1050 Argument : void
1051 Return : void
1052
1053This function flushes to main memory all the image params that are passed to
1054next image. This function is currently invoked in BL2 to flush this information
1055to the next BL image, when LOAD\_IMAGE\_V2 is enabled.
1056
Soby Mathewaaf15f52017-09-04 11:49:29 +01001057Function : plat\_log\_get\_prefix()
1058~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1059
1060::
1061
1062 Argument : unsigned int
1063 Return : const char *
1064
1065This function defines the prefix string corresponding to the `log_level` to be
Dan Handley610e7e12018-03-01 18:44:00 +00001066prepended to all the log output from TF-A. The `log_level` (argument) will
1067correspond to one of the standard log levels defined in debug.h. The platform
1068can override the common implementation to define a different prefix string for
1069the log output. The implementation should be robust to future changes that
1070increase the number of log levels.
Soby Mathewaaf15f52017-09-04 11:49:29 +01001071
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001072Modifications specific to a Boot Loader stage
1073---------------------------------------------
1074
1075Boot Loader Stage 1 (BL1)
1076-------------------------
1077
1078BL1 implements the reset vector where execution starts from after a cold or
1079warm boot. For each CPU, BL1 is responsible for the following tasks:
1080
1081#. Handling the reset as described in section 2.2
1082
1083#. In the case of a cold boot and the CPU being the primary CPU, ensuring that
1084 only this CPU executes the remaining BL1 code, including loading and passing
1085 control to the BL2 stage.
1086
1087#. Identifying and starting the Firmware Update process (if required).
1088
1089#. Loading the BL2 image from non-volatile storage into secure memory at the
1090 address specified by the platform defined constant ``BL2_BASE``.
1091
1092#. Populating a ``meminfo`` structure with the following information in memory,
1093 accessible by BL2 immediately upon entry.
1094
1095 ::
1096
1097 meminfo.total_base = Base address of secure RAM visible to BL2
1098 meminfo.total_size = Size of secure RAM visible to BL2
1099 meminfo.free_base = Base address of secure RAM available for
1100 allocation to BL2
1101 meminfo.free_size = Size of secure RAM available for allocation to BL2
1102
Soby Mathewb1bf0442018-02-16 14:52:52 +00001103 By default, BL1 places this ``meminfo`` structure at the beginning of the
1104 free memory available for its use. Since BL1 cannot allocate memory
1105 dynamically at the moment, its free memory will be available for BL2's use
1106 as-is. However, this means that BL2 must read the ``meminfo`` structure
1107 before it starts using its free memory (this is discussed in Section 3.2).
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001108
Soby Mathewb1bf0442018-02-16 14:52:52 +00001109 It is possible for the platform to decide where it wants to place the
1110 ``meminfo`` structure for BL2 or restrict the amount of memory visible to
1111 BL2 by overriding the weak default implementation of
1112 ``bl1_plat_handle_post_image_load`` API.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001113
1114The following functions need to be implemented by the platform port to enable
1115BL1 to perform the above tasks.
1116
1117Function : bl1\_early\_platform\_setup() [mandatory]
1118~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1119
1120::
1121
1122 Argument : void
1123 Return : void
1124
1125This function executes with the MMU and data caches disabled. It is only called
1126by the primary CPU.
1127
Dan Handley610e7e12018-03-01 18:44:00 +00001128On Arm standard platforms, this function:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001129
1130- Enables a secure instance of SP805 to act as the Trusted Watchdog.
1131
1132- Initializes a UART (PL011 console), which enables access to the ``printf``
1133 family of functions in BL1.
1134
1135- Enables issuing of snoop and DVM (Distributed Virtual Memory) requests to
1136 the CCI slave interface corresponding to the cluster that includes the
1137 primary CPU.
1138
1139Function : bl1\_plat\_arch\_setup() [mandatory]
1140~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1141
1142::
1143
1144 Argument : void
1145 Return : void
1146
1147This function performs any platform-specific and architectural setup that the
1148platform requires. Platform-specific setup might include configuration of
1149memory controllers and the interconnect.
1150
Dan Handley610e7e12018-03-01 18:44:00 +00001151In Arm standard platforms, this function enables the MMU.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001152
1153This function helps fulfill requirement 2 above.
1154
1155Function : bl1\_platform\_setup() [mandatory]
1156~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1157
1158::
1159
1160 Argument : void
1161 Return : void
1162
1163This function executes with the MMU and data caches enabled. It is responsible
1164for performing any remaining platform-specific setup that can occur after the
1165MMU and data cache have been enabled.
1166
Roberto Vargas0cd866c2017-12-12 10:39:44 +00001167if support for multiple boot sources is required, it initializes the boot
1168sequence used by plat\_try\_next\_boot\_source().
1169
Dan Handley610e7e12018-03-01 18:44:00 +00001170In Arm standard platforms, this function initializes the storage abstraction
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001171layer used to load the next bootloader image.
1172
1173This function helps fulfill requirement 4 above.
1174
1175Function : bl1\_plat\_sec\_mem\_layout() [mandatory]
1176~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1177
1178::
1179
1180 Argument : void
1181 Return : meminfo *
1182
1183This function should only be called on the cold boot path. It executes with the
1184MMU and data caches enabled. The pointer returned by this function must point to
1185a ``meminfo`` structure containing the extents and availability of secure RAM for
1186the BL1 stage.
1187
1188::
1189
1190 meminfo.total_base = Base address of secure RAM visible to BL1
1191 meminfo.total_size = Size of secure RAM visible to BL1
1192 meminfo.free_base = Base address of secure RAM available for allocation
1193 to BL1
1194 meminfo.free_size = Size of secure RAM available for allocation to BL1
1195
1196This information is used by BL1 to load the BL2 image in secure RAM. BL1 also
1197populates a similar structure to tell BL2 the extents of memory available for
1198its own use.
1199
1200This function helps fulfill requirements 4 and 5 above.
1201
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001202Function : bl1\_plat\_prepare\_exit() [optional]
1203~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1204
1205::
1206
1207 Argument : entry_point_info_t *
1208 Return : void
1209
1210This function is called prior to exiting BL1 in response to the
1211``BL1_SMC_RUN_IMAGE`` SMC request raised by BL2. It should be used to perform
1212platform specific clean up or bookkeeping operations before transferring
1213control to the next image. It receives the address of the ``entry_point_info_t``
1214structure passed from BL2. This function runs with MMU disabled.
1215
1216Function : bl1\_plat\_set\_ep\_info() [optional]
1217~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1218
1219::
1220
1221 Argument : unsigned int image_id, entry_point_info_t *ep_info
1222 Return : void
1223
1224This function allows platforms to override ``ep_info`` for the given ``image_id``.
1225
1226The default implementation just returns.
1227
1228Function : bl1\_plat\_get\_next\_image\_id() [optional]
1229~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1230
1231::
1232
1233 Argument : void
1234 Return : unsigned int
1235
1236This and the following function must be overridden to enable the FWU feature.
1237
1238BL1 calls this function after platform setup to identify the next image to be
1239loaded and executed. If the platform returns ``BL2_IMAGE_ID`` then BL1 proceeds
1240with the normal boot sequence, which loads and executes BL2. If the platform
1241returns a different image id, BL1 assumes that Firmware Update is required.
1242
Dan Handley610e7e12018-03-01 18:44:00 +00001243The default implementation always returns ``BL2_IMAGE_ID``. The Arm development
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001244platforms override this function to detect if firmware update is required, and
1245if so, return the first image in the firmware update process.
1246
1247Function : bl1\_plat\_get\_image\_desc() [optional]
1248~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1249
1250::
1251
1252 Argument : unsigned int image_id
1253 Return : image_desc_t *
1254
1255BL1 calls this function to get the image descriptor information ``image_desc_t``
1256for the provided ``image_id`` from the platform.
1257
Dan Handley610e7e12018-03-01 18:44:00 +00001258The default implementation always returns a common BL2 image descriptor. Arm
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001259standard platforms return an image descriptor corresponding to BL2 or one of
1260the firmware update images defined in the Trusted Board Boot Requirements
1261specification.
1262
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001263Function : bl1\_plat\_handle\_pre\_image\_load() [optional]
1264~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1265
1266::
1267
Soby Mathew2f38ce32018-02-08 17:45:12 +00001268 Argument : unsigned int image_id
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001269 Return : int
1270
1271This function can be used by the platforms to update/use image information
Soby Mathew2f38ce32018-02-08 17:45:12 +00001272corresponding to ``image_id``. This function is invoked in BL1, both in cold
1273boot and FWU code path, before loading the image.
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001274
1275Function : bl1\_plat\_handle\_post\_image\_load() [optional]
1276~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1277
1278::
1279
Soby Mathew2f38ce32018-02-08 17:45:12 +00001280 Argument : unsigned int image_id
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001281 Return : int
1282
1283This function can be used by the platforms to update/use image information
Soby Mathew2f38ce32018-02-08 17:45:12 +00001284corresponding to ``image_id``. This function is invoked in BL1, both in cold
1285boot and FWU code path, after loading and authenticating the image.
Masahiro Yamada43d20b32018-02-01 16:46:18 +09001286
Soby Mathewb1bf0442018-02-16 14:52:52 +00001287The default weak implementation of this function calculates the amount of
1288Trusted SRAM that can be used by BL2 and allocates a ``meminfo_t``
1289structure at the beginning of this free memory and populates it. The address
1290of ``meminfo_t`` structure is updated in ``arg1`` of the entrypoint
1291information to BL2.
1292
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001293Function : bl1\_plat\_fwu\_done() [optional]
1294~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1295
1296::
1297
1298 Argument : unsigned int image_id, uintptr_t image_src,
1299 unsigned int image_size
1300 Return : void
1301
1302BL1 calls this function when the FWU process is complete. It must not return.
1303The platform may override this function to take platform specific action, for
1304example to initiate the normal boot flow.
1305
1306The default implementation spins forever.
1307
1308Function : bl1\_plat\_mem\_check() [mandatory]
1309~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1310
1311::
1312
1313 Argument : uintptr_t mem_base, unsigned int mem_size,
1314 unsigned int flags
1315 Return : int
1316
1317BL1 calls this function while handling FWU related SMCs, more specifically when
1318copying or authenticating an image. Its responsibility is to ensure that the
1319region of memory identified by ``mem_base`` and ``mem_size`` is mapped in BL1, and
1320that this memory corresponds to either a secure or non-secure memory region as
1321indicated by the security state of the ``flags`` argument.
1322
1323This function can safely assume that the value resulting from the addition of
1324``mem_base`` and ``mem_size`` fits into a ``uintptr_t`` type variable and does not
1325overflow.
1326
1327This function must return 0 on success, a non-null error code otherwise.
1328
1329The default implementation of this function asserts therefore platforms must
1330override it when using the FWU feature.
1331
1332Boot Loader Stage 2 (BL2)
1333-------------------------
1334
1335The BL2 stage is executed only by the primary CPU, which is determined in BL1
1336using the ``platform_is_primary_cpu()`` function. BL1 passed control to BL2 at
1337``BL2_BASE``. BL2 executes in Secure EL1 and is responsible for:
1338
1339#. (Optional) Loading the SCP\_BL2 binary image (if present) from platform
1340 provided non-volatile storage. To load the SCP\_BL2 image, BL2 makes use of
1341 the ``meminfo`` returned by the ``bl2_plat_get_scp_bl2_meminfo()`` function.
1342 The platform also defines the address in memory where SCP\_BL2 is loaded
1343 through the optional constant ``SCP_BL2_BASE``. BL2 uses this information
1344 to determine if there is enough memory to load the SCP\_BL2 image.
1345 Subsequent handling of the SCP\_BL2 image is platform-specific and is
1346 implemented in the ``bl2_plat_handle_scp_bl2()`` function.
1347 If ``SCP_BL2_BASE`` is not defined then this step is not performed.
1348
1349#. Loading the BL31 binary image into secure RAM from non-volatile storage. To
1350 load the BL31 image, BL2 makes use of the ``meminfo`` structure passed to it
1351 by BL1. This structure allows BL2 to calculate how much secure RAM is
1352 available for its use. The platform also defines the address in secure RAM
1353 where BL31 is loaded through the constant ``BL31_BASE``. BL2 uses this
1354 information to determine if there is enough memory to load the BL31 image.
1355
1356#. (Optional) Loading the BL32 binary image (if present) from platform
1357 provided non-volatile storage. To load the BL32 image, BL2 makes use of
1358 the ``meminfo`` returned by the ``bl2_plat_get_bl32_meminfo()`` function.
1359 The platform also defines the address in memory where BL32 is loaded
1360 through the optional constant ``BL32_BASE``. BL2 uses this information
1361 to determine if there is enough memory to load the BL32 image.
1362 If ``BL32_BASE`` is not defined then this and the next step is not performed.
1363
1364#. (Optional) Arranging to pass control to the BL32 image (if present) that
1365 has been pre-loaded at ``BL32_BASE``. BL2 populates an ``entry_point_info``
1366 structure in memory provided by the platform with information about how
1367 BL31 should pass control to the BL32 image.
1368
1369#. (Optional) Loading the normal world BL33 binary image (if not loaded by
1370 other means) into non-secure DRAM from platform storage and arranging for
1371 BL31 to pass control to this image. This address is determined using the
1372 ``plat_get_ns_image_entrypoint()`` function described below.
1373
1374#. BL2 populates an ``entry_point_info`` structure in memory provided by the
1375 platform with information about how BL31 should pass control to the
1376 other BL images.
1377
1378The following functions must be implemented by the platform port to enable BL2
1379to perform the above tasks.
1380
1381Function : bl2\_early\_platform\_setup() [mandatory]
1382~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1383
1384::
1385
1386 Argument : meminfo *
1387 Return : void
1388
1389This function executes with the MMU and data caches disabled. It is only called
1390by the primary CPU. The arguments to this function is the address of the
1391``meminfo`` structure populated by BL1.
1392
1393The platform may copy the contents of the ``meminfo`` structure into a private
1394variable as the original memory may be subsequently overwritten by BL2. The
1395copied structure is made available to all BL2 code through the
1396``bl2_plat_sec_mem_layout()`` function.
1397
Dan Handley610e7e12018-03-01 18:44:00 +00001398On Arm standard platforms, this function also:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001399
1400- Initializes a UART (PL011 console), which enables access to the ``printf``
1401 family of functions in BL2.
1402
1403- Initializes the storage abstraction layer used to load further bootloader
1404 images. It is necessary to do this early on platforms with a SCP\_BL2 image,
1405 since the later ``bl2_platform_setup`` must be done after SCP\_BL2 is loaded.
1406
1407Function : bl2\_plat\_arch\_setup() [mandatory]
1408~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1409
1410::
1411
1412 Argument : void
1413 Return : void
1414
1415This function executes with the MMU and data caches disabled. It is only called
1416by the primary CPU.
1417
1418The purpose of this function is to perform any architectural initialization
1419that varies across platforms.
1420
Dan Handley610e7e12018-03-01 18:44:00 +00001421On Arm standard platforms, this function enables the MMU.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001422
1423Function : bl2\_platform\_setup() [mandatory]
1424~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1425
1426::
1427
1428 Argument : void
1429 Return : void
1430
1431This function may execute with the MMU and data caches enabled if the platform
1432port does the necessary initialization in ``bl2_plat_arch_setup()``. It is only
1433called by the primary CPU.
1434
1435The purpose of this function is to perform any platform initialization
1436specific to BL2.
1437
Dan Handley610e7e12018-03-01 18:44:00 +00001438In Arm standard platforms, this function performs security setup, including
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001439configuration of the TrustZone controller to allow non-secure masters access
1440to most of DRAM. Part of DRAM is reserved for secure world use.
1441
1442Function : bl2\_plat\_sec\_mem\_layout() [mandatory]
1443~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1444
1445::
1446
1447 Argument : void
1448 Return : meminfo *
1449
1450This function should only be called on the cold boot path. It may execute with
1451the MMU and data caches enabled if the platform port does the necessary
1452initialization in ``bl2_plat_arch_setup()``. It is only called by the primary CPU.
1453
1454The purpose of this function is to return a pointer to a ``meminfo`` structure
1455populated with the extents of secure RAM available for BL2 to use. See
1456``bl2_early_platform_setup()`` above.
1457
Masahiro Yamada02a0d3d2018-02-01 16:45:51 +09001458Following functions are optionally used only when LOAD\_IMAGE\_V2 is enabled.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001459
Masahiro Yamada02a0d3d2018-02-01 16:45:51 +09001460Function : bl2\_plat\_handle\_pre\_image\_load() [optional]
1461~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001462
1463::
1464
1465 Argument : unsigned int
1466 Return : int
1467
1468This function can be used by the platforms to update/use image information
Masahiro Yamada02a0d3d2018-02-01 16:45:51 +09001469for given ``image_id``. This function is currently invoked in BL2 before
1470loading each image, when LOAD\_IMAGE\_V2 is enabled.
1471
1472Function : bl2\_plat\_handle\_post\_image\_load() [optional]
1473~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1474
1475::
1476
1477 Argument : unsigned int
1478 Return : int
1479
1480This function can be used by the platforms to update/use image information
1481for given ``image_id``. This function is currently invoked in BL2 after
1482loading each image, when LOAD\_IMAGE\_V2 is enabled.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001483
1484Following functions are required only when LOAD\_IMAGE\_V2 is disabled.
1485
1486Function : bl2\_plat\_get\_scp\_bl2\_meminfo() [mandatory]
1487~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1488
1489::
1490
1491 Argument : meminfo *
1492 Return : void
1493
1494This function is used to get the memory limits where BL2 can load the
1495SCP\_BL2 image. The meminfo provided by this is used by load\_image() to
1496validate whether the SCP\_BL2 image can be loaded within the given
1497memory from the given base.
1498
1499Function : bl2\_plat\_handle\_scp\_bl2() [mandatory]
1500~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1501
1502::
1503
1504 Argument : image_info *
1505 Return : int
1506
1507This function is called after loading SCP\_BL2 image and it is used to perform
1508any platform-specific actions required to handle the SCP firmware. Typically it
1509transfers the image into SCP memory using a platform-specific protocol and waits
1510until SCP executes it and signals to the Application Processor (AP) for BL2
1511execution to continue.
1512
1513This function returns 0 on success, a negative error code otherwise.
1514
1515Function : bl2\_plat\_get\_bl31\_params() [mandatory]
1516~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1517
1518::
1519
1520 Argument : void
1521 Return : bl31_params *
1522
1523BL2 platform code needs to return a pointer to a ``bl31_params`` structure it
1524will use for passing information to BL31. The ``bl31_params`` structure carries
1525the following information.
1526- Header describing the version information for interpreting the bl31\_param
1527structure
1528- Information about executing the BL33 image in the ``bl33_ep_info`` field
1529- Information about executing the BL32 image in the ``bl32_ep_info`` field
1530- Information about the type and extents of BL31 image in the
1531``bl31_image_info`` field
1532- Information about the type and extents of BL32 image in the
1533``bl32_image_info`` field
1534- Information about the type and extents of BL33 image in the
1535``bl33_image_info`` field
1536
1537The memory pointed by this structure and its sub-structures should be
1538accessible from BL31 initialisation code. BL31 might choose to copy the
1539necessary content, or maintain the structures until BL33 is initialised.
1540
1541Funtion : bl2\_plat\_get\_bl31\_ep\_info() [mandatory]
1542~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1543
1544::
1545
1546 Argument : void
1547 Return : entry_point_info *
1548
1549BL2 platform code returns a pointer which is used to populate the entry point
1550information for BL31 entry point. The location pointed by it should be
1551accessible from BL1 while processing the synchronous exception to run to BL31.
1552
Dan Handley610e7e12018-03-01 18:44:00 +00001553In Arm standard platforms this is allocated inside a bl2\_to\_bl31\_params\_mem
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001554structure in BL2 memory.
1555
1556Function : bl2\_plat\_set\_bl31\_ep\_info() [mandatory]
1557~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1558
1559::
1560
1561 Argument : image_info *, entry_point_info *
1562 Return : void
1563
1564In the normal boot flow, this function is called after loading BL31 image and
1565it can be used to overwrite the entry point set by loader and also set the
1566security state and SPSR which represents the entry point system state for BL31.
1567
1568When booting an EL3 payload instead, this function is called after populating
1569its entry point address and can be used for the same purpose for the payload
1570image. It receives a null pointer as its first argument in this case.
1571
1572Function : bl2\_plat\_set\_bl32\_ep\_info() [mandatory]
1573~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1574
1575::
1576
1577 Argument : image_info *, entry_point_info *
1578 Return : void
1579
1580This function is called after loading BL32 image and it can be used to
1581overwrite the entry point set by loader and also set the security state
1582and SPSR which represents the entry point system state for BL32.
1583
1584Function : bl2\_plat\_set\_bl33\_ep\_info() [mandatory]
1585~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1586
1587::
1588
1589 Argument : image_info *, entry_point_info *
1590 Return : void
1591
1592This function is called after loading BL33 image and it can be used to
1593overwrite the entry point set by loader and also set the security state
1594and SPSR which represents the entry point system state for BL33.
1595
1596In the preloaded BL33 alternative boot flow, this function is called after
1597populating its entry point address. It is passed a null pointer as its first
1598argument in this case.
1599
1600Function : bl2\_plat\_get\_bl32\_meminfo() [mandatory]
1601~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1602
1603::
1604
1605 Argument : meminfo *
1606 Return : void
1607
1608This function is used to get the memory limits where BL2 can load the
1609BL32 image. The meminfo provided by this is used by load\_image() to
1610validate whether the BL32 image can be loaded with in the given
1611memory from the given base.
1612
1613Function : bl2\_plat\_get\_bl33\_meminfo() [mandatory]
1614~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1615
1616::
1617
1618 Argument : meminfo *
1619 Return : void
1620
1621This function is used to get the memory limits where BL2 can load the
1622BL33 image. The meminfo provided by this is used by load\_image() to
1623validate whether the BL33 image can be loaded with in the given
1624memory from the given base.
1625
1626This function isn't needed if either ``PRELOADED_BL33_BASE`` or ``EL3_PAYLOAD_BASE``
1627build options are used.
1628
1629Function : bl2\_plat\_flush\_bl31\_params() [mandatory]
1630~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1631
1632::
1633
1634 Argument : void
1635 Return : void
1636
1637Once BL2 has populated all the structures that needs to be read by BL1
1638and BL31 including the bl31\_params structures and its sub-structures,
1639the bl31\_ep\_info structure and any platform specific data. It flushes
1640all these data to the main memory so that it is available when we jump to
1641later Bootloader stages with MMU off
1642
1643Function : plat\_get\_ns\_image\_entrypoint() [mandatory]
1644~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1645
1646::
1647
1648 Argument : void
1649 Return : uintptr_t
1650
1651As previously described, BL2 is responsible for arranging for control to be
1652passed to a normal world BL image through BL31. This function returns the
1653entrypoint of that image, which BL31 uses to jump to it.
1654
1655BL2 is responsible for loading the normal world BL33 image (e.g. UEFI).
1656
1657This function isn't needed if either ``PRELOADED_BL33_BASE`` or ``EL3_PAYLOAD_BASE``
1658build options are used.
1659
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001660Function : bl2\_plat\_preload\_setup [optional]
1661~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1662
1663::
John Tsichritzisee10e792018-06-06 09:38:10 +01001664
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001665 Argument : void
1666 Return : void
1667
1668This optional function performs any BL2 platform initialization
1669required before image loading, that is not done later in
1670bl2\_platform\_setup(). Specifically, if support for multiple
1671boot sources is required, it initializes the boot sequence used by
1672plat\_try\_next\_boot\_source().
1673
1674Function : plat\_try\_next\_boot\_source() [optional]
1675~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1676
1677::
John Tsichritzisee10e792018-06-06 09:38:10 +01001678
Roberto Vargasbc1ae1f2017-09-26 12:53:01 +01001679 Argument : void
1680 Return : int
1681
1682This optional function passes to the next boot source in the redundancy
1683sequence.
1684
1685This function moves the current boot redundancy source to the next
1686element in the boot sequence. If there are no more boot sources then it
1687must return 0, otherwise it must return 1. The default implementation
1688of this always returns 0.
1689
Roberto Vargasb1584272017-11-20 13:36:10 +00001690Boot Loader Stage 2 (BL2) at EL3
1691--------------------------------
1692
Dan Handley610e7e12018-03-01 18:44:00 +00001693When the platform has a non-TF-A Boot ROM it is desirable to jump
1694directly to BL2 instead of TF-A BL1. In this case BL2 is expected to
Roberto Vargasb1584272017-11-20 13:36:10 +00001695execute at EL3 instead of executing at EL1. Refer to the `Firmware
1696Design`_ for more information.
1697
1698All mandatory functions of BL2 must be implemented, except the functions
1699bl2\_early\_platform\_setup and bl2\_el3\_plat\_arch\_setup, because
1700their work is done now by bl2\_el3\_early\_platform\_setup and
1701bl2\_el3\_plat\_arch\_setup. These functions should generally implement
1702the bl1\_plat\_xxx() and bl2\_plat\_xxx() functionality combined.
1703
1704
1705Function : bl2\_el3\_early\_platform\_setup() [mandatory]
1706~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1707
1708::
John Tsichritzisee10e792018-06-06 09:38:10 +01001709
Roberto Vargasb1584272017-11-20 13:36:10 +00001710 Argument : u_register_t, u_register_t, u_register_t, u_register_t
1711 Return : void
1712
1713This function executes with the MMU and data caches disabled. It is only called
1714by the primary CPU. This function receives four parameters which can be used
1715by the platform to pass any needed information from the Boot ROM to BL2.
1716
Dan Handley610e7e12018-03-01 18:44:00 +00001717On Arm standard platforms, this function does the following:
Roberto Vargasb1584272017-11-20 13:36:10 +00001718
1719- Initializes a UART (PL011 console), which enables access to the ``printf``
1720 family of functions in BL2.
1721
1722- Initializes the storage abstraction layer used to load further bootloader
1723 images. It is necessary to do this early on platforms with a SCP\_BL2 image,
1724 since the later ``bl2_platform_setup`` must be done after SCP\_BL2 is loaded.
1725
1726- Initializes the private variables that define the memory layout used.
1727
1728Function : bl2\_el3\_plat\_arch\_setup() [mandatory]
1729~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1730
1731::
John Tsichritzisee10e792018-06-06 09:38:10 +01001732
Roberto Vargasb1584272017-11-20 13:36:10 +00001733 Argument : void
1734 Return : void
1735
1736This function executes with the MMU and data caches disabled. It is only called
1737by the primary CPU.
1738
1739The purpose of this function is to perform any architectural initialization
1740that varies across platforms.
1741
Dan Handley610e7e12018-03-01 18:44:00 +00001742On Arm standard platforms, this function enables the MMU.
Roberto Vargasb1584272017-11-20 13:36:10 +00001743
1744Function : bl2\_el3\_plat\_prepare\_exit() [optional]
1745~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1746
1747::
John Tsichritzisee10e792018-06-06 09:38:10 +01001748
Roberto Vargasb1584272017-11-20 13:36:10 +00001749 Argument : void
1750 Return : void
1751
1752This function is called prior to exiting BL2 and run the next image.
1753It should be used to perform platform specific clean up or bookkeeping
1754operations before transferring control to the next image. This function
1755runs with MMU disabled.
1756
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001757FWU Boot Loader Stage 2 (BL2U)
1758------------------------------
1759
1760The AP Firmware Updater Configuration, BL2U, is an optional part of the FWU
1761process and is executed only by the primary CPU. BL1 passes control to BL2U at
1762``BL2U_BASE``. BL2U executes in Secure-EL1 and is responsible for:
1763
1764#. (Optional) Transfering the optional SCP\_BL2U binary image from AP secure
1765 memory to SCP RAM. BL2U uses the SCP\_BL2U ``image_info`` passed by BL1.
1766 ``SCP_BL2U_BASE`` defines the address in AP secure memory where SCP\_BL2U
1767 should be copied from. Subsequent handling of the SCP\_BL2U image is
1768 implemented by the platform specific ``bl2u_plat_handle_scp_bl2u()`` function.
1769 If ``SCP_BL2U_BASE`` is not defined then this step is not performed.
1770
1771#. Any platform specific setup required to perform the FWU process. For
Dan Handley610e7e12018-03-01 18:44:00 +00001772 example, Arm standard platforms initialize the TZC controller so that the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001773 normal world can access DDR memory.
1774
1775The following functions must be implemented by the platform port to enable
1776BL2U to perform the tasks mentioned above.
1777
1778Function : bl2u\_early\_platform\_setup() [mandatory]
1779~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1780
1781::
1782
1783 Argument : meminfo *mem_info, void *plat_info
1784 Return : void
1785
1786This function executes with the MMU and data caches disabled. It is only
1787called by the primary CPU. The arguments to this function is the address
1788of the ``meminfo`` structure and platform specific info provided by BL1.
1789
1790The platform may copy the contents of the ``mem_info`` and ``plat_info`` into
1791private storage as the original memory may be subsequently overwritten by BL2U.
1792
Dan Handley610e7e12018-03-01 18:44:00 +00001793On Arm CSS platforms ``plat_info`` is interpreted as an ``image_info_t`` structure,
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001794to extract SCP\_BL2U image information, which is then copied into a private
1795variable.
1796
1797Function : bl2u\_plat\_arch\_setup() [mandatory]
1798~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1799
1800::
1801
1802 Argument : void
1803 Return : void
1804
1805This function executes with the MMU and data caches disabled. It is only
1806called by the primary CPU.
1807
1808The purpose of this function is to perform any architectural initialization
1809that varies across platforms, for example enabling the MMU (since the memory
1810map differs across platforms).
1811
1812Function : bl2u\_platform\_setup() [mandatory]
1813~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1814
1815::
1816
1817 Argument : void
1818 Return : void
1819
1820This function may execute with the MMU and data caches enabled if the platform
1821port does the necessary initialization in ``bl2u_plat_arch_setup()``. It is only
1822called by the primary CPU.
1823
1824The purpose of this function is to perform any platform initialization
1825specific to BL2U.
1826
Dan Handley610e7e12018-03-01 18:44:00 +00001827In Arm standard platforms, this function performs security setup, including
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001828configuration of the TrustZone controller to allow non-secure masters access
1829to most of DRAM. Part of DRAM is reserved for secure world use.
1830
1831Function : bl2u\_plat\_handle\_scp\_bl2u() [optional]
1832~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1833
1834::
1835
1836 Argument : void
1837 Return : int
1838
1839This function is used to perform any platform-specific actions required to
1840handle the SCP firmware. Typically it transfers the image into SCP memory using
1841a platform-specific protocol and waits until SCP executes it and signals to the
1842Application Processor (AP) for BL2U execution to continue.
1843
1844This function returns 0 on success, a negative error code otherwise.
1845This function is included if SCP\_BL2U\_BASE is defined.
1846
1847Boot Loader Stage 3-1 (BL31)
1848----------------------------
1849
1850During cold boot, the BL31 stage is executed only by the primary CPU. This is
1851determined in BL1 using the ``platform_is_primary_cpu()`` function. BL1 passes
1852control to BL31 at ``BL31_BASE``. During warm boot, BL31 is executed by all
1853CPUs. BL31 executes at EL3 and is responsible for:
1854
1855#. Re-initializing all architectural and platform state. Although BL1 performs
1856 some of this initialization, BL31 remains resident in EL3 and must ensure
1857 that EL3 architectural and platform state is completely initialized. It
1858 should make no assumptions about the system state when it receives control.
1859
1860#. Passing control to a normal world BL image, pre-loaded at a platform-
1861 specific address by BL2. BL31 uses the ``entry_point_info`` structure that BL2
1862 populated in memory to do this.
1863
1864#. Providing runtime firmware services. Currently, BL31 only implements a
1865 subset of the Power State Coordination Interface (PSCI) API as a runtime
1866 service. See Section 3.3 below for details of porting the PSCI
1867 implementation.
1868
1869#. Optionally passing control to the BL32 image, pre-loaded at a platform-
1870 specific address by BL2. BL31 exports a set of apis that allow runtime
1871 services to specify the security state in which the next image should be
1872 executed and run the corresponding image. BL31 uses the ``entry_point_info``
1873 structure populated by BL2 to do this.
1874
1875If BL31 is a reset vector, It also needs to handle the reset as specified in
1876section 2.2 before the tasks described above.
1877
1878The following functions must be implemented by the platform port to enable BL31
1879to perform the above tasks.
1880
1881Function : bl31\_early\_platform\_setup() [mandatory]
1882~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1883
1884::
1885
1886 Argument : bl31_params *, void *
1887 Return : void
1888
1889This function executes with the MMU and data caches disabled. It is only called
1890by the primary CPU. The arguments to this function are:
1891
1892- The address of the ``bl31_params`` structure populated by BL2.
1893- An opaque pointer that the platform may use as needed.
1894
1895The platform can copy the contents of the ``bl31_params`` structure and its
1896sub-structures into private variables if the original memory may be
1897subsequently overwritten by BL31 and similarly the ``void *`` pointing
1898to the platform data also needs to be saved.
1899
Dan Handley610e7e12018-03-01 18:44:00 +00001900In Arm standard platforms, BL2 passes a pointer to a ``bl31_params`` structure
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001901in BL2 memory. BL31 copies the information in this pointer to internal data
1902structures. It also performs the following:
1903
1904- Initialize a UART (PL011 console), which enables access to the ``printf``
1905 family of functions in BL31.
1906
1907- Enable issuing of snoop and DVM (Distributed Virtual Memory) requests to the
1908 CCI slave interface corresponding to the cluster that includes the primary
1909 CPU.
1910
1911Function : bl31\_plat\_arch\_setup() [mandatory]
1912~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1913
1914::
1915
1916 Argument : void
1917 Return : void
1918
1919This function executes with the MMU and data caches disabled. It is only called
1920by the primary CPU.
1921
1922The purpose of this function is to perform any architectural initialization
1923that varies across platforms.
1924
Dan Handley610e7e12018-03-01 18:44:00 +00001925On Arm standard platforms, this function enables the MMU.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001926
1927Function : bl31\_platform\_setup() [mandatory]
1928~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1929
1930::
1931
1932 Argument : void
1933 Return : void
1934
1935This function may execute with the MMU and data caches enabled if the platform
1936port does the necessary initialization in ``bl31_plat_arch_setup()``. It is only
1937called by the primary CPU.
1938
1939The purpose of this function is to complete platform initialization so that both
1940BL31 runtime services and normal world software can function correctly.
1941
Dan Handley610e7e12018-03-01 18:44:00 +00001942On Arm standard platforms, this function does the following:
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001943
1944- Initialize the generic interrupt controller.
1945
1946 Depending on the GIC driver selected by the platform, the appropriate GICv2
1947 or GICv3 initialization will be done, which mainly consists of:
1948
1949 - Enable secure interrupts in the GIC CPU interface.
1950 - Disable the legacy interrupt bypass mechanism.
1951 - Configure the priority mask register to allow interrupts of all priorities
1952 to be signaled to the CPU interface.
1953 - Mark SGIs 8-15 and the other secure interrupts on the platform as secure.
1954 - Target all secure SPIs to CPU0.
1955 - Enable these secure interrupts in the GIC distributor.
1956 - Configure all other interrupts as non-secure.
1957 - Enable signaling of secure interrupts in the GIC distributor.
1958
1959- Enable system-level implementation of the generic timer counter through the
1960 memory mapped interface.
1961
1962- Grant access to the system counter timer module
1963
1964- Initialize the power controller device.
1965
1966 In particular, initialise the locks that prevent concurrent accesses to the
1967 power controller device.
1968
1969Function : bl31\_plat\_runtime\_setup() [optional]
1970~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1971
1972::
1973
1974 Argument : void
1975 Return : void
1976
1977The purpose of this function is allow the platform to perform any BL31 runtime
1978setup just prior to BL31 exit during cold boot. The default weak
Julius Werneraae9bb12017-09-18 16:49:48 -07001979implementation of this function will invoke ``console_switch_state()`` to switch
1980console output to consoles marked for use in the ``runtime`` state.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001981
Sandrine Bailleux842117d2018-05-14 14:25:47 +02001982Function : bl31\_plat\_get\_next\_image\_ep\_info() [mandatory]
1983~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001984
1985::
1986
Sandrine Bailleux842117d2018-05-14 14:25:47 +02001987 Argument : uint32_t
Douglas Raillardd7c21b72017-06-28 15:23:03 +01001988 Return : entry_point_info *
1989
1990This function may execute with the MMU and data caches enabled if the platform
1991port does the necessary initializations in ``bl31_plat_arch_setup()``.
1992
1993This function is called by ``bl31_main()`` to retrieve information provided by
1994BL2 for the next image in the security state specified by the argument. BL31
1995uses this information to pass control to that image in the specified security
1996state. This function must return a pointer to the ``entry_point_info`` structure
1997(that was copied during ``bl31_early_platform_setup()``) if the image exists. It
1998should return NULL otherwise.
1999
Jeenu Viswambharane834ee12018-04-27 15:17:03 +01002000Function : bl31_plat_enable_mmu [optional]
2001~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2002
2003::
2004
2005 Argument : uint32_t
2006 Return : void
2007
2008This function enables the MMU. The boot code calls this function with MMU and
2009caches disabled. This function should program necessary registers to enable
2010translation, and upon return, the MMU on the calling PE must be enabled.
2011
2012The function must honor flags passed in the first argument. These flags are
2013defined by the translation library, and can be found in the file
2014``include/lib/xlat_tables/xlat_mmu_helpers.h``.
2015
2016On DynamIQ systems, this function must not use stack while enabling MMU, which
2017is how the function in xlat table library version 2 is implementated.
2018
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002019Function : plat\_get\_syscnt\_freq2() [mandatory]
2020~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2021
2022::
2023
2024 Argument : void
2025 Return : unsigned int
2026
2027This function is used by the architecture setup code to retrieve the counter
2028frequency for the CPU's generic timer. This value will be programmed into the
Dan Handley610e7e12018-03-01 18:44:00 +00002029``CNTFRQ_EL0`` register. In Arm standard platforms, it returns the base frequency
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002030of the system counter, which is retrieved from the first entry in the frequency
2031modes table.
2032
2033#define : PLAT\_PERCPU\_BAKERY\_LOCK\_SIZE [optional]
2034~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2035
2036When ``USE_COHERENT_MEM = 0``, this constant defines the total memory (in
2037bytes) aligned to the cache line boundary that should be allocated per-cpu to
2038accommodate all the bakery locks.
2039
2040If this constant is not defined when ``USE_COHERENT_MEM = 0``, the linker
2041calculates the size of the ``bakery_lock`` input section, aligns it to the
2042nearest ``CACHE_WRITEBACK_GRANULE``, multiplies it with ``PLATFORM_CORE_COUNT``
2043and stores the result in a linker symbol. This constant prevents a platform
2044from relying on the linker and provide a more efficient mechanism for
2045accessing per-cpu bakery lock information.
2046
2047If this constant is defined and its value is not equal to the value
2048calculated by the linker then a link time assertion is raised. A compile time
2049assertion is raised if the value of the constant is not aligned to the cache
2050line boundary.
2051
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002052SDEI porting requirements
2053~~~~~~~~~~~~~~~~~~~~~~~~~
2054
2055The SDEI dispatcher requires the platform to provide the following macros
2056and functions, of which some are optional, and some others mandatory.
2057
2058Macros
2059......
2060
2061Macro: PLAT_SDEI_NORMAL_PRI [mandatory]
2062^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2063
2064This macro must be defined to the EL3 exception priority level associated with
2065Normal SDEI events on the platform. This must have a higher value (therefore of
2066lower priority) than ``PLAT_SDEI_CRITICAL_PRI``.
2067
2068Macro: PLAT_SDEI_CRITICAL_PRI [mandatory]
2069^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2070
2071This macro must be defined to the EL3 exception priority level associated with
2072Critical SDEI events on the platform. This must have a lower value (therefore of
2073higher priority) than ``PLAT_SDEI_NORMAL_PRI``.
2074
Jeenu Viswambharan7af48132018-01-16 09:29:30 +00002075**Note**: SDEI exception priorities must be the lowest among Secure priorities.
2076Among the SDEI exceptions, Critical SDEI priority must be higher than Normal
2077SDEI priority.
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002078
2079Functions
2080.........
2081
2082Function: int plat_sdei_validate_entry_point(uintptr_t ep) [optional]
2083^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2084
2085::
2086
2087 Argument: uintptr_t
2088 Return: int
2089
2090This function validates the address of client entry points provided for both
2091event registration and *Complete and Resume* SDEI calls. The function takes one
2092argument, which is the address of the handler the SDEI client requested to
2093register. The function must return ``0`` for successful validation, or ``-1``
2094upon failure.
2095
Dan Handley610e7e12018-03-01 18:44:00 +00002096The default implementation always returns ``0``. On Arm platforms, this function
Jeenu Viswambharan04e3a7f2017-10-16 08:43:14 +01002097is implemented to translate the entry point to physical address, and further to
2098ensure that the address is located in Non-secure DRAM.
2099
2100Function: void plat_sdei_handle_masked_trigger(uint64_t mpidr, unsigned int intr) [optional]
2101^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
2102
2103::
2104
2105 Argument: uint64_t
2106 Argument: unsigned int
2107 Return: void
2108
2109SDEI specification requires that a PE comes out of reset with the events masked.
2110The client therefore is expected to call ``PE_UNMASK`` to unmask SDEI events on
2111the PE. No SDEI events can be dispatched until such time.
2112
2113Should a PE receive an interrupt that was bound to an SDEI event while the
2114events are masked on the PE, the dispatcher implementation invokes the function
2115``plat_sdei_handle_masked_trigger``. The MPIDR of the PE that received the
2116interrupt and the interrupt ID are passed as parameters.
2117
2118The default implementation only prints out a warning message.
2119
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002120Power State Coordination Interface (in BL31)
2121--------------------------------------------
2122
Dan Handley610e7e12018-03-01 18:44:00 +00002123The TF-A implementation of the PSCI API is based around the concept of a
2124*power domain*. A *power domain* is a CPU or a logical group of CPUs which
2125share some state on which power management operations can be performed as
2126specified by `PSCI`_. Each CPU in the system is assigned a cpu index which is
2127a unique number between ``0`` and ``PLATFORM_CORE_COUNT - 1``. The
2128*power domains* are arranged in a hierarchical tree structure and each
2129*power domain* can be identified in a system by the cpu index of any CPU that
2130is part of that domain and a *power domain level*. A processing element (for
2131example, a CPU) is at level 0. If the *power domain* node above a CPU is a
2132logical grouping of CPUs that share some state, then level 1 is that group of
2133CPUs (for example, a cluster), and level 2 is a group of clusters (for
2134example, the system). More details on the power domain topology and its
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002135organization can be found in `Power Domain Topology Design`_.
2136
2137BL31's platform initialization code exports a pointer to the platform-specific
2138power management operations required for the PSCI implementation to function
2139correctly. This information is populated in the ``plat_psci_ops`` structure. The
2140PSCI implementation calls members of the ``plat_psci_ops`` structure for performing
2141power management operations on the power domains. For example, the target
2142CPU is specified by its ``MPIDR`` in a PSCI ``CPU_ON`` call. The ``pwr_domain_on()``
2143handler (if present) is called for the CPU power domain.
2144
2145The ``power-state`` parameter of a PSCI ``CPU_SUSPEND`` call can be used to
2146describe composite power states specific to a platform. The PSCI implementation
2147defines a generic representation of the power-state parameter viz which is an
2148array of local power states where each index corresponds to a power domain
2149level. Each entry contains the local power state the power domain at that power
2150level could enter. It depends on the ``validate_power_state()`` handler to
2151convert the power-state parameter (possibly encoding a composite power state)
2152passed in a PSCI ``CPU_SUSPEND`` call to this representation.
2153
2154The following functions form part of platform port of PSCI functionality.
2155
2156Function : plat\_psci\_stat\_accounting\_start() [optional]
2157~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2158
2159::
2160
2161 Argument : const psci_power_state_t *
2162 Return : void
2163
2164This is an optional hook that platforms can implement for residency statistics
2165accounting before entering a low power state. The ``pwr_domain_state`` field of
2166``state_info`` (first argument) can be inspected if stat accounting is done
2167differently at CPU level versus higher levels. As an example, if the element at
2168index 0 (CPU power level) in the ``pwr_domain_state`` array indicates a power down
2169state, special hardware logic may be programmed in order to keep track of the
2170residency statistics. For higher levels (array indices > 0), the residency
2171statistics could be tracked in software using PMF. If ``ENABLE_PMF`` is set, the
2172default implementation will use PMF to capture timestamps.
2173
2174Function : plat\_psci\_stat\_accounting\_stop() [optional]
2175~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2176
2177::
2178
2179 Argument : const psci_power_state_t *
2180 Return : void
2181
2182This is an optional hook that platforms can implement for residency statistics
2183accounting after exiting from a low power state. The ``pwr_domain_state`` field
2184of ``state_info`` (first argument) can be inspected if stat accounting is done
2185differently at CPU level versus higher levels. As an example, if the element at
2186index 0 (CPU power level) in the ``pwr_domain_state`` array indicates a power down
2187state, special hardware logic may be programmed in order to keep track of the
2188residency statistics. For higher levels (array indices > 0), the residency
2189statistics could be tracked in software using PMF. If ``ENABLE_PMF`` is set, the
2190default implementation will use PMF to capture timestamps.
2191
2192Function : plat\_psci\_stat\_get\_residency() [optional]
2193~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2194
2195::
2196
2197 Argument : unsigned int, const psci_power_state_t *, int
2198 Return : u_register_t
2199
2200This is an optional interface that is is invoked after resuming from a low power
2201state and provides the time spent resident in that low power state by the power
2202domain at a particular power domain level. When a CPU wakes up from suspend,
2203all its parent power domain levels are also woken up. The generic PSCI code
2204invokes this function for each parent power domain that is resumed and it
2205identified by the ``lvl`` (first argument) parameter. The ``state_info`` (second
2206argument) describes the low power state that the power domain has resumed from.
2207The current CPU is the first CPU in the power domain to resume from the low
2208power state and the ``last_cpu_idx`` (third parameter) is the index of the last
2209CPU in the power domain to suspend and may be needed to calculate the residency
2210for that power domain.
2211
2212Function : plat\_get\_target\_pwr\_state() [optional]
2213~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2214
2215::
2216
2217 Argument : unsigned int, const plat_local_state_t *, unsigned int
2218 Return : plat_local_state_t
2219
2220The PSCI generic code uses this function to let the platform participate in
2221state coordination during a power management operation. The function is passed
2222a pointer to an array of platform specific local power state ``states`` (second
2223argument) which contains the requested power state for each CPU at a particular
2224power domain level ``lvl`` (first argument) within the power domain. The function
2225is expected to traverse this array of upto ``ncpus`` (third argument) and return
2226a coordinated target power state by the comparing all the requested power
2227states. The target power state should not be deeper than any of the requested
2228power states.
2229
2230A weak definition of this API is provided by default wherein it assumes
2231that the platform assigns a local state value in order of increasing depth
2232of the power state i.e. for two power states X & Y, if X < Y
2233then X represents a shallower power state than Y. As a result, the
2234coordinated target local power state for a power domain will be the minimum
2235of the requested local power state values.
2236
2237Function : plat\_get\_power\_domain\_tree\_desc() [mandatory]
2238~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2239
2240::
2241
2242 Argument : void
2243 Return : const unsigned char *
2244
2245This function returns a pointer to the byte array containing the power domain
2246topology tree description. The format and method to construct this array are
2247described in `Power Domain Topology Design`_. The BL31 PSCI initilization code
2248requires this array to be described by the platform, either statically or
2249dynamically, to initialize the power domain topology tree. In case the array
2250is populated dynamically, then plat\_core\_pos\_by\_mpidr() and
2251plat\_my\_core\_pos() should also be implemented suitably so that the topology
2252tree description matches the CPU indices returned by these APIs. These APIs
2253together form the platform interface for the PSCI topology framework.
2254
2255Function : plat\_setup\_psci\_ops() [mandatory]
Douglas Raillard0929f092017-08-02 14:44:42 +01002256~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002257
2258::
2259
2260 Argument : uintptr_t, const plat_psci_ops **
2261 Return : int
2262
2263This function may execute with the MMU and data caches enabled if the platform
2264port does the necessary initializations in ``bl31_plat_arch_setup()``. It is only
2265called by the primary CPU.
2266
2267This function is called by PSCI initialization code. Its purpose is to let
2268the platform layer know about the warm boot entrypoint through the
2269``sec_entrypoint`` (first argument) and to export handler routines for
2270platform-specific psci power management actions by populating the passed
2271pointer with a pointer to BL31's private ``plat_psci_ops`` structure.
2272
2273A description of each member of this structure is given below. Please refer to
Dan Handley610e7e12018-03-01 18:44:00 +00002274the Arm FVP specific implementation of these handlers in
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002275`plat/arm/board/fvp/fvp\_pm.c`_ as an example. For each PSCI function that the
2276platform wants to support, the associated operation or operations in this
2277structure must be provided and implemented (Refer section 4 of
Dan Handley610e7e12018-03-01 18:44:00 +00002278`Firmware Design`_ for the PSCI API supported in TF-A). To disable a PSCI
2279function in a platform port, the operation should be removed from this
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002280structure instead of providing an empty implementation.
2281
2282plat\_psci\_ops.cpu\_standby()
Douglas Raillard0929f092017-08-02 14:44:42 +01002283..............................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002284
2285Perform the platform-specific actions to enter the standby state for a cpu
2286indicated by the passed argument. This provides a fast path for CPU standby
2287wherein overheads of PSCI state management and lock acquistion is avoided.
2288For this handler to be invoked by the PSCI ``CPU_SUSPEND`` API implementation,
2289the suspend state type specified in the ``power-state`` parameter should be
2290STANDBY and the target power domain level specified should be the CPU. The
2291handler should put the CPU into a low power retention state (usually by
2292issuing a wfi instruction) and ensure that it can be woken up from that
2293state by a normal interrupt. The generic code expects the handler to succeed.
2294
2295plat\_psci\_ops.pwr\_domain\_on()
Douglas Raillard0929f092017-08-02 14:44:42 +01002296.................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002297
2298Perform the platform specific actions to power on a CPU, specified
2299by the ``MPIDR`` (first argument). The generic code expects the platform to
2300return PSCI\_E\_SUCCESS on success or PSCI\_E\_INTERN\_FAIL for any failure.
2301
2302plat\_psci\_ops.pwr\_domain\_off()
Douglas Raillard0929f092017-08-02 14:44:42 +01002303..................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002304
2305Perform the platform specific actions to prepare to power off the calling CPU
2306and its higher parent power domain levels as indicated by the ``target_state``
2307(first argument). It is called by the PSCI ``CPU_OFF`` API implementation.
2308
2309The ``target_state`` encodes the platform coordinated target local power states
2310for the CPU power domain and its parent power domain levels. The handler
2311needs to perform power management operation corresponding to the local state
2312at each power level.
2313
2314For this handler, the local power state for the CPU power domain will be a
2315power down state where as it could be either power down, retention or run state
2316for the higher power domain levels depending on the result of state
2317coordination. The generic code expects the handler to succeed.
2318
Varun Wadekarae87f4b2017-07-10 16:02:05 -07002319plat\_psci\_ops.pwr\_domain\_suspend\_pwrdown\_early() [optional]
Douglas Raillard0929f092017-08-02 14:44:42 +01002320.................................................................
Varun Wadekarae87f4b2017-07-10 16:02:05 -07002321
2322This optional function may be used as a performance optimization to replace
2323or complement pwr_domain_suspend() on some platforms. Its calling semantics
2324are identical to pwr_domain_suspend(), except the PSCI implementation only
2325calls this function when suspending to a power down state, and it guarantees
2326that data caches are enabled.
2327
2328When HW_ASSISTED_COHERENCY = 0, the PSCI implementation disables data caches
2329before calling pwr_domain_suspend(). If the target_state corresponds to a
2330power down state and it is safe to perform some or all of the platform
2331specific actions in that function with data caches enabled, it may be more
2332efficient to move those actions to this function. When HW_ASSISTED_COHERENCY
2333= 1, data caches remain enabled throughout, and so there is no advantage to
2334moving platform specific actions to this function.
2335
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002336plat\_psci\_ops.pwr\_domain\_suspend()
Douglas Raillard0929f092017-08-02 14:44:42 +01002337......................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002338
2339Perform the platform specific actions to prepare to suspend the calling
2340CPU and its higher parent power domain levels as indicated by the
2341``target_state`` (first argument). It is called by the PSCI ``CPU_SUSPEND``
2342API implementation.
2343
2344The ``target_state`` has a similar meaning as described in
2345the ``pwr_domain_off()`` operation. It encodes the platform coordinated
2346target local power states for the CPU power domain and its parent
2347power domain levels. The handler needs to perform power management operation
2348corresponding to the local state at each power level. The generic code
2349expects the handler to succeed.
2350
Douglas Raillarda84996b2017-08-02 16:57:32 +01002351The difference between turning a power domain off versus suspending it is that
2352in the former case, the power domain is expected to re-initialize its state
2353when it is next powered on (see ``pwr_domain_on_finish()``). In the latter
2354case, the power domain is expected to save enough state so that it can resume
2355execution by restoring this state when its powered on (see
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002356``pwr_domain_suspend_finish()``).
2357
Douglas Raillarda84996b2017-08-02 16:57:32 +01002358When suspending a core, the platform can also choose to power off the GICv3
2359Redistributor and ITS through an implementation-defined sequence. To achieve
2360this safely, the ITS context must be saved first. The architectural part is
2361implemented by the ``gicv3_its_save_disable()`` helper, but most of the needed
2362sequence is implementation defined and it is therefore the responsibility of
2363the platform code to implement the necessary sequence. Then the GIC
2364Redistributor context can be saved using the ``gicv3_rdistif_save()`` helper.
2365Powering off the Redistributor requires the implementation to support it and it
2366is the responsibility of the platform code to execute the right implementation
2367defined sequence.
2368
2369When a system suspend is requested, the platform can also make use of the
2370``gicv3_distif_save()`` helper to save the context of the GIC Distributor after
2371it has saved the context of the Redistributors and ITS of all the cores in the
2372system. The context of the Distributor can be large and may require it to be
2373allocated in a special area if it cannot fit in the platform's global static
2374data, for example in DRAM. The Distributor can then be powered down using an
2375implementation-defined sequence.
2376
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002377plat\_psci\_ops.pwr\_domain\_pwr\_down\_wfi()
Douglas Raillard0929f092017-08-02 14:44:42 +01002378.............................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002379
2380This is an optional function and, if implemented, is expected to perform
2381platform specific actions including the ``wfi`` invocation which allows the
2382CPU to powerdown. Since this function is invoked outside the PSCI locks,
2383the actions performed in this hook must be local to the CPU or the platform
2384must ensure that races between multiple CPUs cannot occur.
2385
2386The ``target_state`` has a similar meaning as described in the ``pwr_domain_off()``
2387operation and it encodes the platform coordinated target local power states for
2388the CPU power domain and its parent power domain levels. This function must
2389not return back to the caller.
2390
2391If this function is not implemented by the platform, PSCI generic
2392implementation invokes ``psci_power_down_wfi()`` for power down.
2393
2394plat\_psci\_ops.pwr\_domain\_on\_finish()
Douglas Raillard0929f092017-08-02 14:44:42 +01002395.........................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002396
2397This function is called by the PSCI implementation after the calling CPU is
2398powered on and released from reset in response to an earlier PSCI ``CPU_ON`` call.
2399It performs the platform-specific setup required to initialize enough state for
2400this CPU to enter the normal world and also provide secure runtime firmware
2401services.
2402
2403The ``target_state`` (first argument) is the prior state of the power domains
2404immediately before the CPU was turned on. It indicates which power domains
2405above the CPU might require initialization due to having previously been in
2406low power states. The generic code expects the handler to succeed.
2407
2408plat\_psci\_ops.pwr\_domain\_suspend\_finish()
Douglas Raillard0929f092017-08-02 14:44:42 +01002409..............................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002410
2411This function is called by the PSCI implementation after the calling CPU is
2412powered on and released from reset in response to an asynchronous wakeup
2413event, for example a timer interrupt that was programmed by the CPU during the
2414``CPU_SUSPEND`` call or ``SYSTEM_SUSPEND`` call. It performs the platform-specific
2415setup required to restore the saved state for this CPU to resume execution
2416in the normal world and also provide secure runtime firmware services.
2417
2418The ``target_state`` (first argument) has a similar meaning as described in
2419the ``pwr_domain_on_finish()`` operation. The generic code expects the platform
2420to succeed.
2421
Douglas Raillarda84996b2017-08-02 16:57:32 +01002422If the Distributor, Redistributors or ITS have been powered off as part of a
2423suspend, their context must be restored in this function in the reverse order
2424to how they were saved during suspend sequence.
2425
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002426plat\_psci\_ops.system\_off()
Douglas Raillard0929f092017-08-02 14:44:42 +01002427.............................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002428
2429This function is called by PSCI implementation in response to a ``SYSTEM_OFF``
2430call. It performs the platform-specific system poweroff sequence after
2431notifying the Secure Payload Dispatcher.
2432
2433plat\_psci\_ops.system\_reset()
Douglas Raillard0929f092017-08-02 14:44:42 +01002434...............................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002435
2436This function is called by PSCI implementation in response to a ``SYSTEM_RESET``
2437call. It performs the platform-specific system reset sequence after
2438notifying the Secure Payload Dispatcher.
2439
2440plat\_psci\_ops.validate\_power\_state()
Douglas Raillard0929f092017-08-02 14:44:42 +01002441........................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002442
2443This function is called by the PSCI implementation during the ``CPU_SUSPEND``
2444call to validate the ``power_state`` parameter of the PSCI API and if valid,
2445populate it in ``req_state`` (second argument) array as power domain level
2446specific local states. If the ``power_state`` is invalid, the platform must
2447return PSCI\_E\_INVALID\_PARAMS as error, which is propagated back to the
2448normal world PSCI client.
2449
2450plat\_psci\_ops.validate\_ns\_entrypoint()
Douglas Raillard0929f092017-08-02 14:44:42 +01002451..........................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002452
2453This function is called by the PSCI implementation during the ``CPU_SUSPEND``,
2454``SYSTEM_SUSPEND`` and ``CPU_ON`` calls to validate the non-secure ``entry_point``
2455parameter passed by the normal world. If the ``entry_point`` is invalid,
2456the platform must return PSCI\_E\_INVALID\_ADDRESS as error, which is
2457propagated back to the normal world PSCI client.
2458
2459plat\_psci\_ops.get\_sys\_suspend\_power\_state()
Douglas Raillard0929f092017-08-02 14:44:42 +01002460.................................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002461
2462This function is called by the PSCI implementation during the ``SYSTEM_SUSPEND``
2463call to get the ``req_state`` parameter from platform which encodes the power
2464domain level specific local states to suspend to system affinity level. The
2465``req_state`` will be utilized to do the PSCI state coordination and
2466``pwr_domain_suspend()`` will be invoked with the coordinated target state to
2467enter system suspend.
2468
2469plat\_psci\_ops.get\_pwr\_lvl\_state\_idx()
Douglas Raillard0929f092017-08-02 14:44:42 +01002470...........................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002471
2472This is an optional function and, if implemented, is invoked by the PSCI
2473implementation to convert the ``local_state`` (first argument) at a specified
2474``pwr_lvl`` (second argument) to an index between 0 and
2475``PLAT_MAX_PWR_LVL_STATES`` - 1. This function is only needed if the platform
2476supports more than two local power states at each power domain level, that is
2477``PLAT_MAX_PWR_LVL_STATES`` is greater than 2, and needs to account for these
2478local power states.
2479
2480plat\_psci\_ops.translate\_power\_state\_by\_mpidr()
Douglas Raillard0929f092017-08-02 14:44:42 +01002481....................................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002482
2483This is an optional function and, if implemented, verifies the ``power_state``
2484(second argument) parameter of the PSCI API corresponding to a target power
2485domain. The target power domain is identified by using both ``MPIDR`` (first
2486argument) and the power domain level encoded in ``power_state``. The power domain
2487level specific local states are to be extracted from ``power_state`` and be
2488populated in the ``output_state`` (third argument) array. The functionality
2489is similar to the ``validate_power_state`` function described above and is
2490envisaged to be used in case the validity of ``power_state`` depend on the
2491targeted power domain. If the ``power_state`` is invalid for the targeted power
2492domain, the platform must return PSCI\_E\_INVALID\_PARAMS as error. If this
2493function is not implemented, then the generic implementation relies on
2494``validate_power_state`` function to translate the ``power_state``.
2495
2496This function can also be used in case the platform wants to support local
2497power state encoding for ``power_state`` parameter of PSCI\_STAT\_COUNT/RESIDENCY
2498APIs as described in Section 5.18 of `PSCI`_.
2499
2500plat\_psci\_ops.get\_node\_hw\_state()
Douglas Raillard0929f092017-08-02 14:44:42 +01002501......................................
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002502
2503This is an optional function. If implemented this function is intended to return
2504the power state of a node (identified by the first parameter, the ``MPIDR``) in
2505the power domain topology (identified by the second parameter, ``power_level``),
2506as retrieved from a power controller or equivalent component on the platform.
2507Upon successful completion, the implementation must map and return the final
2508status among ``HW_ON``, ``HW_OFF`` or ``HW_STANDBY``. Upon encountering failures, it
2509must return either ``PSCI_E_INVALID_PARAMS`` or ``PSCI_E_NOT_SUPPORTED`` as
2510appropriate.
2511
2512Implementations are not expected to handle ``power_levels`` greater than
2513``PLAT_MAX_PWR_LVL``.
2514
Roberto Vargasd963e3e2017-09-12 10:28:35 +01002515plat\_psci\_ops.system\_reset2()
2516................................
2517
2518This is an optional function. If implemented this function is
2519called during the ``SYSTEM_RESET2`` call to perform a reset
2520based on the first parameter ``reset_type`` as specified in
2521`PSCI`_. The parameter ``cookie`` can be used to pass additional
2522reset information. If the ``reset_type`` is not supported, the
2523function must return ``PSCI_E_NOT_SUPPORTED``. For architectural
2524resets, all failures must return ``PSCI_E_INVALID_PARAMETERS``
2525and vendor reset can return other PSCI error codes as defined
2526in `PSCI`_. On success this function will not return.
2527
2528plat\_psci\_ops.write\_mem\_protect()
2529....................................
2530
2531This is an optional function. If implemented it enables or disables the
2532``MEM_PROTECT`` functionality based on the value of ``val``.
2533A non-zero value enables ``MEM_PROTECT`` and a value of zero
2534disables it. Upon encountering failures it must return a negative value
2535and on success it must return 0.
2536
2537plat\_psci\_ops.read\_mem\_protect()
2538.....................................
2539
2540This is an optional function. If implemented it returns the current
2541state of ``MEM_PROTECT`` via the ``val`` parameter. Upon encountering
2542failures it must return a negative value and on success it must
2543return 0.
2544
2545plat\_psci\_ops.mem\_protect\_chk()
2546...................................
2547
2548This is an optional function. If implemented it checks if a memory
2549region defined by a base address ``base`` and with a size of ``length``
2550bytes is protected by ``MEM_PROTECT``. If the region is protected
2551then it must return 0, otherwise it must return a negative number.
2552
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002553Interrupt Management framework (in BL31)
2554----------------------------------------
2555
2556BL31 implements an Interrupt Management Framework (IMF) to manage interrupts
2557generated in either security state and targeted to EL1 or EL2 in the non-secure
2558state or EL3/S-EL1 in the secure state. The design of this framework is
2559described in the `IMF Design Guide`_
2560
2561A platform should export the following APIs to support the IMF. The following
Dan Handley610e7e12018-03-01 18:44:00 +00002562text briefly describes each api and its implementation in Arm standard
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002563platforms. The API implementation depends upon the type of interrupt controller
Dan Handley610e7e12018-03-01 18:44:00 +00002564present in the platform. Arm standard platform layer supports both
2565`Arm Generic Interrupt Controller version 2.0 (GICv2)`_
2566and `3.0 (GICv3)`_. Juno builds the Arm platform layer to use GICv2 and the
2567FVP can be configured to use either GICv2 or GICv3 depending on the build flag
2568``FVP_USE_GIC_DRIVER`` (See FVP platform specific build options in
2569`User Guide`_ for more details).
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002570
Jeenu Viswambharanb1e957e2017-09-22 08:32:09 +01002571See also: `Interrupt Controller Abstraction APIs`__.
2572
2573.. __: platform-interrupt-controller-API.rst
2574
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002575Function : plat\_interrupt\_type\_to\_line() [mandatory]
2576~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2577
2578::
2579
2580 Argument : uint32_t, uint32_t
2581 Return : uint32_t
2582
Dan Handley610e7e12018-03-01 18:44:00 +00002583The Arm processor signals an interrupt exception either through the IRQ or FIQ
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002584interrupt line. The specific line that is signaled depends on how the interrupt
2585controller (IC) reports different interrupt types from an execution context in
2586either security state. The IMF uses this API to determine which interrupt line
2587the platform IC uses to signal each type of interrupt supported by the framework
2588from a given security state. This API must be invoked at EL3.
2589
2590The first parameter will be one of the ``INTR_TYPE_*`` values (see
2591`IMF Design Guide`_) indicating the target type of the interrupt, the second parameter is the
2592security state of the originating execution context. The return result is the
2593bit position in the ``SCR_EL3`` register of the respective interrupt trap: IRQ=1,
2594FIQ=2.
2595
Dan Handley610e7e12018-03-01 18:44:00 +00002596In the case of Arm standard platforms using GICv2, S-EL1 interrupts are
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002597configured as FIQs and Non-secure interrupts as IRQs from either security
2598state.
2599
Dan Handley610e7e12018-03-01 18:44:00 +00002600In the case of Arm standard platforms using GICv3, the interrupt line to be
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002601configured depends on the security state of the execution context when the
2602interrupt is signalled and are as follows:
2603
2604- The S-EL1 interrupts are signaled as IRQ in S-EL0/1 context and as FIQ in
2605 NS-EL0/1/2 context.
2606- The Non secure interrupts are signaled as FIQ in S-EL0/1 context and as IRQ
2607 in the NS-EL0/1/2 context.
2608- The EL3 interrupts are signaled as FIQ in both S-EL0/1 and NS-EL0/1/2
2609 context.
2610
2611Function : plat\_ic\_get\_pending\_interrupt\_type() [mandatory]
2612~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2613
2614::
2615
2616 Argument : void
2617 Return : uint32_t
2618
2619This API returns the type of the highest priority pending interrupt at the
2620platform IC. The IMF uses the interrupt type to retrieve the corresponding
2621handler function. ``INTR_TYPE_INVAL`` is returned when there is no interrupt
2622pending. The valid interrupt types that can be returned are ``INTR_TYPE_EL3``,
2623``INTR_TYPE_S_EL1`` and ``INTR_TYPE_NS``. This API must be invoked at EL3.
2624
Dan Handley610e7e12018-03-01 18:44:00 +00002625In the case of Arm standard platforms using GICv2, the *Highest Priority
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002626Pending Interrupt Register* (``GICC_HPPIR``) is read to determine the id of
2627the pending interrupt. The type of interrupt depends upon the id value as
2628follows.
2629
2630#. id < 1022 is reported as a S-EL1 interrupt
2631#. id = 1022 is reported as a Non-secure interrupt.
2632#. id = 1023 is reported as an invalid interrupt type.
2633
Dan Handley610e7e12018-03-01 18:44:00 +00002634In the case of Arm standard platforms using GICv3, the system register
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002635``ICC_HPPIR0_EL1``, *Highest Priority Pending group 0 Interrupt Register*,
2636is read to determine the id of the pending interrupt. The type of interrupt
2637depends upon the id value as follows.
2638
2639#. id = ``PENDING_G1S_INTID`` (1020) is reported as a S-EL1 interrupt
2640#. id = ``PENDING_G1NS_INTID`` (1021) is reported as a Non-secure interrupt.
2641#. id = ``GIC_SPURIOUS_INTERRUPT`` (1023) is reported as an invalid interrupt type.
2642#. All other interrupt id's are reported as EL3 interrupt.
2643
2644Function : plat\_ic\_get\_pending\_interrupt\_id() [mandatory]
2645~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2646
2647::
2648
2649 Argument : void
2650 Return : uint32_t
2651
2652This API returns the id of the highest priority pending interrupt at the
2653platform IC. ``INTR_ID_UNAVAILABLE`` is returned when there is no interrupt
2654pending.
2655
Dan Handley610e7e12018-03-01 18:44:00 +00002656In the case of Arm standard platforms using GICv2, the *Highest Priority
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002657Pending Interrupt Register* (``GICC_HPPIR``) is read to determine the id of the
2658pending interrupt. The id that is returned by API depends upon the value of
2659the id read from the interrupt controller as follows.
2660
2661#. id < 1022. id is returned as is.
2662#. id = 1022. The *Aliased Highest Priority Pending Interrupt Register*
2663 (``GICC_AHPPIR``) is read to determine the id of the non-secure interrupt.
2664 This id is returned by the API.
2665#. id = 1023. ``INTR_ID_UNAVAILABLE`` is returned.
2666
Dan Handley610e7e12018-03-01 18:44:00 +00002667In the case of Arm standard platforms using GICv3, if the API is invoked from
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002668EL3, the system register ``ICC_HPPIR0_EL1``, *Highest Priority Pending Interrupt
2669group 0 Register*, is read to determine the id of the pending interrupt. The id
2670that is returned by API depends upon the value of the id read from the
2671interrupt controller as follows.
2672
2673#. id < ``PENDING_G1S_INTID`` (1020). id is returned as is.
2674#. id = ``PENDING_G1S_INTID`` (1020) or ``PENDING_G1NS_INTID`` (1021). The system
2675 register ``ICC_HPPIR1_EL1``, *Highest Priority Pending Interrupt group 1
2676 Register* is read to determine the id of the group 1 interrupt. This id
2677 is returned by the API as long as it is a valid interrupt id
2678#. If the id is any of the special interrupt identifiers,
2679 ``INTR_ID_UNAVAILABLE`` is returned.
2680
2681When the API invoked from S-EL1 for GICv3 systems, the id read from system
2682register ``ICC_HPPIR1_EL1``, *Highest Priority Pending group 1 Interrupt
2683Register*, is returned if is not equal to GIC\_SPURIOUS\_INTERRUPT (1023) else
2684``INTR_ID_UNAVAILABLE`` is returned.
2685
2686Function : plat\_ic\_acknowledge\_interrupt() [mandatory]
2687~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2688
2689::
2690
2691 Argument : void
2692 Return : uint32_t
2693
2694This API is used by the CPU to indicate to the platform IC that processing of
Jeenu Viswambharan055af4b2017-10-24 15:13:59 +01002695the highest pending interrupt has begun. It should return the raw, unmodified
2696value obtained from the interrupt controller when acknowledging an interrupt.
2697The actual interrupt number shall be extracted from this raw value using the API
2698`plat_ic_get_interrupt_id()`__.
2699
2700.. __: platform-interrupt-controller-API.rst#function-unsigned-int-plat-ic-get-interrupt-id-unsigned-int-raw-optional
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002701
Dan Handley610e7e12018-03-01 18:44:00 +00002702This function in Arm standard platforms using GICv2, reads the *Interrupt
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002703Acknowledge Register* (``GICC_IAR``). This changes the state of the highest
2704priority pending interrupt from pending to active in the interrupt controller.
Jeenu Viswambharan055af4b2017-10-24 15:13:59 +01002705It returns the value read from the ``GICC_IAR``, unmodified.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002706
Dan Handley610e7e12018-03-01 18:44:00 +00002707In the case of Arm standard platforms using GICv3, if the API is invoked
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002708from EL3, the function reads the system register ``ICC_IAR0_EL1``, *Interrupt
2709Acknowledge Register group 0*. If the API is invoked from S-EL1, the function
2710reads the system register ``ICC_IAR1_EL1``, *Interrupt Acknowledge Register
2711group 1*. The read changes the state of the highest pending interrupt from
2712pending to active in the interrupt controller. The value read is returned
Jeenu Viswambharan055af4b2017-10-24 15:13:59 +01002713unmodified.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002714
2715The TSP uses this API to start processing of the secure physical timer
2716interrupt.
2717
2718Function : plat\_ic\_end\_of\_interrupt() [mandatory]
2719~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2720
2721::
2722
2723 Argument : uint32_t
2724 Return : void
2725
2726This API is used by the CPU to indicate to the platform IC that processing of
2727the interrupt corresponding to the id (passed as the parameter) has
2728finished. The id should be the same as the id returned by the
2729``plat_ic_acknowledge_interrupt()`` API.
2730
Dan Handley610e7e12018-03-01 18:44:00 +00002731Arm standard platforms write the id to the *End of Interrupt Register*
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002732(``GICC_EOIR``) in case of GICv2, and to ``ICC_EOIR0_EL1`` or ``ICC_EOIR1_EL1``
2733system register in case of GICv3 depending on where the API is invoked from,
2734EL3 or S-EL1. This deactivates the corresponding interrupt in the interrupt
2735controller.
2736
2737The TSP uses this API to finish processing of the secure physical timer
2738interrupt.
2739
2740Function : plat\_ic\_get\_interrupt\_type() [mandatory]
2741~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2742
2743::
2744
2745 Argument : uint32_t
2746 Return : uint32_t
2747
2748This API returns the type of the interrupt id passed as the parameter.
2749``INTR_TYPE_INVAL`` is returned if the id is invalid. If the id is valid, a valid
2750interrupt type (one of ``INTR_TYPE_EL3``, ``INTR_TYPE_S_EL1`` and ``INTR_TYPE_NS``) is
2751returned depending upon how the interrupt has been configured by the platform
2752IC. This API must be invoked at EL3.
2753
Dan Handley610e7e12018-03-01 18:44:00 +00002754Arm standard platforms using GICv2 configures S-EL1 interrupts as Group0 interrupts
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002755and Non-secure interrupts as Group1 interrupts. It reads the group value
2756corresponding to the interrupt id from the relevant *Interrupt Group Register*
2757(``GICD_IGROUPRn``). It uses the group value to determine the type of interrupt.
2758
Dan Handley610e7e12018-03-01 18:44:00 +00002759In the case of Arm standard platforms using GICv3, both the *Interrupt Group
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002760Register* (``GICD_IGROUPRn``) and *Interrupt Group Modifier Register*
2761(``GICD_IGRPMODRn``) is read to figure out whether the interrupt is configured
2762as Group 0 secure interrupt, Group 1 secure interrupt or Group 1 NS interrupt.
2763
2764Crash Reporting mechanism (in BL31)
2765-----------------------------------
2766
Julius Werneraae9bb12017-09-18 16:49:48 -07002767NOTE: This section assumes that your platform is enabling the MULTI_CONSOLE_API
2768flag in its platform.mk. Not using this flag is deprecated for new platforms.
2769
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002770BL31 implements a crash reporting mechanism which prints the various registers
Julius Werneraae9bb12017-09-18 16:49:48 -07002771of the CPU to enable quick crash analysis and debugging. By default, the
2772definitions in ``plat/common/aarch64/platform\_helpers.S`` will cause the crash
2773output to be routed over the normal console infrastructure and get printed on
2774consoles configured to output in crash state. ``console_set_scope()`` can be
2775used to control whether a console is used for crash output.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002776
Julius Werneraae9bb12017-09-18 16:49:48 -07002777In some cases (such as debugging very early crashes that happen before the
2778normal boot console can be set up), platforms may want to control crash output
2779more explicitly. For these, the following functions can be overridden by
2780platform code. They are executed outside of a C environment and without a stack.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002781
2782Function : plat\_crash\_console\_init
2783~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2784
2785::
2786
2787 Argument : void
2788 Return : int
2789
2790This API is used by the crash reporting mechanism to initialize the crash
Julius Werneraae9bb12017-09-18 16:49:48 -07002791console. It must only use the general purpose registers x0 through x7 to do the
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002792initialization and returns 1 on success.
2793
Julius Werneraae9bb12017-09-18 16:49:48 -07002794If you are trying to debug crashes before the console driver would normally get
2795registered, you can use this to register a driver from assembly with hardcoded
2796parameters. For example, you could register the 16550 driver like this:
2797
2798::
2799
2800 .section .data.crash_console /* Reserve space for console structure */
2801 crash_console:
2802 .zero 6 * 8 /* console_16550_t has 6 8-byte words */
2803 func plat_crash_console_init
2804 ldr x0, =YOUR_16550_BASE_ADDR
2805 ldr x1, =YOUR_16550_SRCCLK_IN_HZ
2806 ldr x2, =YOUR_16550_TARGET_BAUD_RATE
2807 adrp x3, crash_console
2808 add x3, x3, :lo12:crash_console
2809 b console_16550_register /* tail call, returns 1 on success */
2810 endfunc plat_crash_console_init
2811
2812If you're trying to debug crashes in BL1, you can call the console_xxx_core_init
2813function exported by some console drivers from here.
2814
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002815Function : plat\_crash\_console\_putc
2816~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2817
2818::
2819
2820 Argument : int
2821 Return : int
2822
2823This API is used by the crash reporting mechanism to print a character on the
2824designated crash console. It must only use general purpose registers x1 and
2825x2 to do its work. The parameter and the return value are in general purpose
2826register x0.
2827
Julius Werneraae9bb12017-09-18 16:49:48 -07002828If you have registered a normal console driver in ``plat_crash_console_init``,
2829you can keep the default implementation here (which calls ``console_putc()``).
2830
2831If you're trying to debug crashes in BL1, you can call the console_xxx_core_putc
2832function exported by some console drivers from here.
2833
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002834Function : plat\_crash\_console\_flush
2835~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2836
2837::
2838
2839 Argument : void
2840 Return : int
2841
2842This API is used by the crash reporting mechanism to force write of all buffered
2843data on the designated crash console. It should only use general purpose
Julius Werneraae9bb12017-09-18 16:49:48 -07002844registers x0 through x5 to do its work. The return value is 0 on successful
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002845completion; otherwise the return value is -1.
2846
Julius Werneraae9bb12017-09-18 16:49:48 -07002847If you have registered a normal console driver in ``plat_crash_console_init``,
2848you can keep the default implementation here (which calls ``console_flush()``).
2849
2850If you're trying to debug crashes in BL1, you can call the console_xx_core_flush
2851function exported by some console drivers from here.
2852
Jeenu Viswambharanbf235bc2018-07-12 10:00:01 +01002853Extternal Abort handling and RAS Support
2854----------------------------------------
2855
2856Function : plat_ea_handler
2857~~~~~~~~~~~~~~~~~~~~~~~~~~
2858
2859::
2860
2861 Argument : int
2862 Argument : uint64_t
2863 Argument : void *
2864 Argument : void *
2865 Argument : uint64_t
2866 Return : void
2867
2868This function is invoked by the RAS framework for the platform to handle an
2869External Abort received at EL3. The intention of the function is to attempt to
2870resolve the cause of External Abort and return; if that's not possible, to
2871initiate orderly shutdown of the system.
2872
2873The first parameter (``int ea_reason``) indicates the reason for External Abort.
2874Its value is one of ``ERROR_EA_*`` constants defined in ``ea_handle.h``.
2875
2876The second parameter (``uint64_t syndrome``) is the respective syndrome
2877presented to EL3 after having received the External Abort. Depending on the
2878nature of the abort (as can be inferred from the ``ea_reason`` parameter), this
2879can be the content of either ``ESR_EL3`` or ``DISR_EL1``.
2880
2881The third parameter (``void *cookie``) is unused for now. The fourth parameter
2882(``void *handle``) is a pointer to the preempted context. The fifth parameter
2883(``uint64_t flags``) indicates the preempted security state. These parameters
2884are received from the top-level exception handler.
2885
2886If ``RAS_EXTENSION`` is set to ``1``, the default implementation of this
2887function iterates through RAS handlers registered by the platform. If any of the
2888RAS handlers resolve the External Abort, no further action is taken.
2889
2890If ``RAS_EXTENSION`` is set to ``0``, or if none of the platform RAS handlers
2891could resolve the External Abort, the default implementation prints an error
2892message, and panics.
2893
2894Function : plat_handle_uncontainable_ea
2895~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2896
2897::
2898
2899 Argument : int
2900 Argument : uint64_t
2901 Return : void
2902
2903This function is invoked by the RAS framework when an External Abort of
2904Uncontainable type is received at EL3. Due to the critical nature of
2905Uncontainable errors, the intention of this function is to initiate orderly
2906shutdown of the system, and is not expected to return.
2907
2908This function must be implemented in assembly.
2909
2910The first and second parameters are the same as that of ``plat_ea_handler``.
2911
2912The default implementation of this function calls
2913``report_unhandled_exception``.
2914
2915Function : plat_handle_double_fault
2916~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2917
2918::
2919
2920 Argument : int
2921 Argument : uint64_t
2922 Return : void
2923
2924This function is invoked by the RAS framework when another External Abort is
2925received at EL3 while one is already being handled. I.e., a call to
2926``plat_ea_handler`` is outstanding. Due to its critical nature, the intention of
2927this function is to initiate orderly shutdown of the system, and is not expected
2928recover or return.
2929
2930This function must be implemented in assembly.
2931
2932The first and second parameters are the same as that of ``plat_ea_handler``.
2933
2934The default implementation of this function calls
2935``report_unhandled_exception``.
2936
2937Function : plat_handle_el3_ea
2938~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2939
2940::
2941
2942 Return : void
2943
2944This function is invoked when an External Abort is received while executing in
2945EL3. Due to its critical nature, the intention of this function is to initiate
2946orderly shutdown of the system, and is not expected recover or return.
2947
2948This function must be implemented in assembly.
2949
2950The default implementation of this function calls
2951``report_unhandled_exception``.
2952
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002953Build flags
2954-----------
2955
2956- **ENABLE\_PLAT\_COMPAT**
2957 All the platforms ports conforming to this API specification should define
2958 the build flag ``ENABLE_PLAT_COMPAT`` to 0 as the compatibility layer should
2959 be disabled. For more details on compatibility layer, refer
2960 `Migration Guide`_.
2961
2962There are some build flags which can be defined by the platform to control
2963inclusion or exclusion of certain BL stages from the FIP image. These flags
2964need to be defined in the platform makefile which will get included by the
2965build system.
2966
2967- **NEED\_BL33**
2968 By default, this flag is defined ``yes`` by the build system and ``BL33``
2969 build option should be supplied as a build option. The platform has the
2970 option of excluding the BL33 image in the ``fip`` image by defining this flag
2971 to ``no``. If any of the options ``EL3_PAYLOAD_BASE`` or ``PRELOADED_BL33_BASE``
2972 are used, this flag will be set to ``no`` automatically.
2973
2974C Library
2975---------
2976
2977To avoid subtle toolchain behavioral dependencies, the header files provided
2978by the compiler are not used. The software is built with the ``-nostdinc`` flag
2979to ensure no headers are included from the toolchain inadvertently. Instead the
Dan Handley610e7e12018-03-01 18:44:00 +00002980required headers are included in the TF-A source tree. The library only
2981contains those C library definitions required by the local implementation. If
2982more functionality is required, the needed library functions will need to be
2983added to the local implementation.
Douglas Raillardd7c21b72017-06-28 15:23:03 +01002984
2985Versions of `FreeBSD`_ headers can be found in ``include/lib/stdlib``. Some of
2986these headers have been cut down in order to simplify the implementation. In
2987order to minimize changes to the header files, the `FreeBSD`_ layout has been
2988maintained. The generic C library definitions can be found in
2989``include/lib/stdlib`` with more system and machine specific declarations in
2990``include/lib/stdlib/sys`` and ``include/lib/stdlib/machine``.
2991
2992The local C library implementations can be found in ``lib/stdlib``. In order to
2993extend the C library these files may need to be modified. It is recommended to
2994use a release version of `FreeBSD`_ as a starting point.
2995
2996The C library header files in the `FreeBSD`_ source tree are located in the
2997``include`` and ``sys/sys`` directories. `FreeBSD`_ machine specific definitions
2998can be found in the ``sys/<machine-type>`` directories. These files define things
2999like 'the size of a pointer' and 'the range of an integer'. Since an AArch64
3000port for `FreeBSD`_ does not yet exist, the machine specific definitions are
3001based on existing machine types with similar properties (for example SPARC64).
3002
3003Where possible, C library function implementations were taken from `FreeBSD`_
3004as found in the ``lib/libc`` directory.
3005
3006A copy of the `FreeBSD`_ sources can be downloaded with ``git``.
3007
3008::
3009
3010 git clone git://github.com/freebsd/freebsd.git -b origin/release/9.2.0
3011
3012Storage abstraction layer
3013-------------------------
3014
3015In order to improve platform independence and portability an storage abstraction
3016layer is used to load data from non-volatile platform storage.
3017
3018Each platform should register devices and their drivers via the Storage layer.
3019These drivers then need to be initialized by bootloader phases as
3020required in their respective ``blx_platform_setup()`` functions. Currently
3021storage access is only required by BL1 and BL2 phases. The ``load_image()``
3022function uses the storage layer to access non-volatile platform storage.
3023
Dan Handley610e7e12018-03-01 18:44:00 +00003024It is mandatory to implement at least one storage driver. For the Arm
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003025development platforms the Firmware Image Package (FIP) driver is provided as
3026the default means to load data from storage (see the "Firmware Image Package"
3027section in the `User Guide`_). The storage layer is described in the header file
3028``include/drivers/io/io_storage.h``. The implementation of the common library
3029is in ``drivers/io/io_storage.c`` and the driver files are located in
3030``drivers/io/``.
3031
3032Each IO driver must provide ``io_dev_*`` structures, as described in
3033``drivers/io/io_driver.h``. These are returned via a mandatory registration
3034function that is called on platform initialization. The semi-hosting driver
3035implementation in ``io_semihosting.c`` can be used as an example.
3036
3037The Storage layer provides mechanisms to initialize storage devices before
3038IO operations are called. The basic operations supported by the layer
3039include ``open()``, ``close()``, ``read()``, ``write()``, ``size()`` and ``seek()``.
3040Drivers do not have to implement all operations, but each platform must
3041provide at least one driver for a device capable of supporting generic
3042operations such as loading a bootloader image.
3043
3044The current implementation only allows for known images to be loaded by the
3045firmware. These images are specified by using their identifiers, as defined in
3046[include/plat/common/platform\_def.h] (or a separate header file included from
3047there). The platform layer (``plat_get_image_source()``) then returns a reference
3048to a device and a driver-specific ``spec`` which will be understood by the driver
3049to allow access to the image data.
3050
3051The layer is designed in such a way that is it possible to chain drivers with
3052other drivers. For example, file-system drivers may be implemented on top of
3053physical block devices, both represented by IO devices with corresponding
3054drivers. In such a case, the file-system "binding" with the block device may
3055be deferred until the file-system device is initialised.
3056
3057The abstraction currently depends on structures being statically allocated
3058by the drivers and callers, as the system does not yet provide a means of
3059dynamically allocating memory. This may also have the affect of limiting the
3060amount of open resources per driver.
3061
3062--------------
3063
Dan Handley610e7e12018-03-01 18:44:00 +00003064*Copyright (c) 2013-2018, Arm Limited and Contributors. All rights reserved.*
Douglas Raillardd7c21b72017-06-28 15:23:03 +01003065
3066.. _Migration Guide: platform-migration-guide.rst
3067.. _include/plat/common/platform.h: ../include/plat/common/platform.h
3068.. _include/plat/arm/common/plat\_arm.h: ../include/plat/arm/common/plat_arm.h%5D
3069.. _User Guide: user-guide.rst
3070.. _include/plat/common/common\_def.h: ../include/plat/common/common_def.h
3071.. _include/plat/arm/common/arm\_def.h: ../include/plat/arm/common/arm_def.h
3072.. _plat/common/aarch64/platform\_mp\_stack.S: ../plat/common/aarch64/platform_mp_stack.S
3073.. _plat/common/aarch64/platform\_up\_stack.S: ../plat/common/aarch64/platform_up_stack.S
3074.. _For example, define the build flag in platform.mk: PLAT_PL061_MAX_GPIOS%20:=%20160
3075.. _Power Domain Topology Design: psci-pd-tree.rst
3076.. _include/common/bl\_common.h: ../include/common/bl_common.h
3077.. _include/lib/aarch32/arch.h: ../include/lib/aarch32/arch.h
3078.. _Firmware Design: firmware-design.rst
3079.. _PSCI: http://infocenter.arm.com/help/topic/com.arm.doc.den0022c/DEN0022C_Power_State_Coordination_Interface.pdf
3080.. _plat/arm/board/fvp/fvp\_pm.c: ../plat/arm/board/fvp/fvp_pm.c
3081.. _IMF Design Guide: interrupt-framework-design.rst
Dan Handley610e7e12018-03-01 18:44:00 +00003082.. _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 +01003083.. _3.0 (GICv3): http://infocenter.arm.com/help/topic/com.arm.doc.ihi0069b/index.html
3084.. _FreeBSD: http://www.freebsd.org