| Qualcomm MSM8916 |
| ================ |
| The MSM8916 platform port in TF-A supports multiple similar Qualcomm SoCs: |
| |
| +-----------------------+----------------+-------------------+-----------------+ |
| | System-on-Chip (SoC) | TF-A Platform | Application CPU | Supports | |
| +=======================+================+===================+=================+ |
| | `Snapdragon 410`_ |``PLAT=msm8916``| 4x ARM Cortex-A53 | AArch64/AArch32 | |
| | (MSM8x16, APQ8016(E)) | | | | |
| | (`DragonBoard 410c`_) | | | | |
| +-----------------------+----------------+-------------------+-----------------+ |
| | `Snapdragon 615`_ |``PLAT=msm8939``| 4x ARM Cortex-A53 | AArch64/AArch32 | |
| | (MSM8x39, APQ8039) | | 4x ARM Cortex-A53 | | |
| +-----------------------+----------------+-------------------+-----------------+ |
| | `Snapdragon 210`_ |``PLAT=msm8909``| 4x ARM Cortex-A7 | AArch32 only | |
| | (MSM8x09, APQ8009) | | | | |
| +-----------------------+----------------+-------------------+-----------------+ |
| | `Snapdragon X5 Modem`_|``PLAT=mdm9607``| 1x ARM Cortex-A7 | AArch32 only | |
| | (MDM9x07) | | | | |
| +-----------------------+----------------+-------------------+-----------------+ |
| |
| It provides a minimal, community-maintained EL3 firmware and PSCI implementation, |
| based on information from the public `Snapdragon 410E Technical Reference Manual`_ |
| combined with a lot of trial and error to actually make it work. |
| |
| .. note:: |
| Unlike the :doc:`QTI SC7180/SC7280 <qti>` ports, this port does **not** |
| make use of a proprietary binary components (QTISECLIB). It is fully |
| open-source but therefore limited to publicly documented hardware |
| components. |
| |
| Functionality |
| ------------- |
| The TF-A port is much more minimal compared to the original firmware and |
| therefore expects the non-secure world (e.g. Linux) to manage more hardware, |
| such as the SMMUs and all remote processors (RPM, WCNSS, Venus, Modem). |
| Everything except modem is currently functional with a slightly modified version |
| of mainline Linux. |
| |
| .. warning:: |
| This port is **not secure**. There is no special secure memory and the |
| used DRAM is available from both the non-secure and secure worlds. |
| Unfortunately, the hardware used for memory protection is not described |
| in the APQ8016E documentation. |
| |
| The port is primarily intended as a minimal PSCI implementation (without a |
| separate secure world) where this limitation is not a big problem. Booting |
| secondary CPU cores (PSCI ``CPU_ON``) is supported. Basic CPU core power |
| management (``CPU_SUSPEND``) is functional but still work-in-progress and |
| will be added later once ready. |
| |
| Boot Flow |
| --------- |
| BL31 (AArch64) or BL32/SP_MIN (AArch32) replaces the original ``tz`` firmware |
| in the boot flow:: |
| |
| Boot ROM (PBL) -> SBL -> BL31 (EL3) -> U-Boot (EL2) -> Linux (EL2) |
| |
| After initialization the normal world starts at a fixed entry address in EL2/HYP |
| mode, configured using ``PRELOADED_BL33_BASE``. At runtime, it is expected that |
| the normal world bootloader was already loaded into RAM by a previous firmware |
| component (usually SBL) and that it is capable of running in EL2/HYP mode. |
| |
| `U-Boot for DragonBoard 410c`_ is recommended if possible. The original Little |
| Kernel-based bootloader from Qualcomm does not support EL2/HYP, but can be |
| booted using an additional shim loader such as `tfalkstub`_. |
| |
| Build |
| ----- |
| It is possible to build for either AArch64 or AArch32. Some platforms use 32-bit |
| CPUs that only support AArch32 (see table above). For all others AArch64 is the |
| preferred build option. |
| |
| AArch64 (BL31) |
| ^^^^^^^^^^^^^^ |
| Setup the cross compiler for AArch64 and build BL31 for one of the platforms in |
| the table above:: |
| |
| $ make CROSS_COMPILE=aarch64-none-elf- PLAT=... |
| |
| The BL31 ELF image is generated in ``build/$PLAT/release/bl31/bl31.elf``. |
| |
| AArch32 (BL32/SP_MIN) |
| ^^^^^^^^^^^^^^^^^^^^^ |
| Setup the cross compiler for AArch32 and build BL32 with SP_MIN for one of the |
| platforms in the table above:: |
| |
| $ make CROSS_COMPILE=arm-none-eabi- PLAT=... ARCH=aarch32 AARCH32_SP=sp_min |
| |
| The BL32 ELF image is generated in ``build/$PLAT/release/bl32/bl32.elf``. |
| |
| Build Options |
| ------------- |
| Some options can be changed at build time by adding them to the make command line: |
| |
| * ``QTI_UART_NUM``: Number of UART controller to use for debug output and crash |
| reports. This must be the same UART as used by earlier boot firmware since |
| the UART controller does not get fully initialized at the moment. Defaults to |
| the usual debug UART used for the platform (see ``platform.mk``). |
| * ``QTI_RUNTIME_UART``: By default (``0``) the UART is only used for the boot |
| process and critical crashes. If set to ``1`` it is also used for runtime |
| messages. Note that this option can only be used if the UART is reserved in |
| the normal world and the necessary clocks remain enabled. |
| |
| The memory region used for the different firmware components is not fixed and |
| can be changed on the make command line. The default values match the addresses |
| used by the original firmware (see ``platform.mk``): |
| |
| * ``PRELOADED_BL33_BASE``: The entry address for the normal world. Usually |
| refers to the first bootloader (e.g. U-Boot). |
| * ``BL31_BASE``: Base address for the BL31 firmware component. Must point to |
| a 64K-aligned memory region with at least 128 KiB space that is permanently |
| reserved in the normal world. |
| * ``BL32_BASE``: Base address for the BL32 firmware component. |
| |
| * **AArch32:** BL32 is used in place of BL31, so the option is equivalent to |
| ``BL31_BASE``. |
| * **AArch64:** Secure-EL1 Payload. Defaults to using 128 KiB of space |
| directly after BL31. For testing only, the port is primarily intended as |
| a minimal PSCI implementation without a separate secure world. |
| |
| Installation |
| ------------ |
| The ELF image must be "signed" before flashing it, even if the board has secure |
| boot disabled. In this case the signature does not provide any security, |
| but it provides the firmware with required metadata. |
| |
| The `DragonBoard 410c`_ does not have secure boot enabled by default. In this |
| case you can simply sign the ELF image using a randomly generated key. You can |
| use e.g. `qtestsign`_:: |
| |
| $ ./qtestsign.py tz build/msm8916/release/bl31/bl31.elf |
| |
| Then install the resulting ``build/msm8916/release/bl31/bl31-test-signed.mbn`` |
| to the ``tz`` partition on the device. BL31 should be running after a reboot. |
| |
| .. note:: |
| On AArch32 the ELF image is called ``bl32.elf``. |
| The installation procedure is identical. |
| |
| .. warning:: |
| Do not flash incorrectly signed firmware on devices that have secure |
| boot enabled! Make sure that you have a way to recover the board in case |
| of problems (e.g. using EDL). |
| |
| Boot Trace |
| ---------- |
| |
| AArch64 (BL31) |
| ^^^^^^^^^^^^^^ |
| BL31 prints some lines on the debug console, which will usually look like this |
| (with ``DEBUG=1``, otherwise only the ``NOTICE`` lines are shown):: |
| |
| ... |
| S - DDR Frequency, 400 MHz |
| NOTICE: BL31: v2.6(debug):v2.6 |
| NOTICE: BL31: Built : 20:00:00, Dec 01 2021 |
| INFO: BL31: Platform setup start |
| INFO: ARM GICv2 driver initialized |
| INFO: BL31: Platform setup done |
| INFO: BL31: Initializing runtime services |
| INFO: BL31: cortex_a53: CPU workaround for 819472 was applied |
| INFO: BL31: cortex_a53: CPU workaround for 824069 was applied |
| INFO: BL31: cortex_a53: CPU workaround for 826319 was applied |
| INFO: BL31: cortex_a53: CPU workaround for 827319 was applied |
| INFO: BL31: cortex_a53: CPU workaround for 835769 was applied |
| INFO: BL31: cortex_a53: CPU workaround for disable_non_temporal_hint was applied |
| INFO: BL31: cortex_a53: CPU workaround for 843419 was applied |
| INFO: BL31: cortex_a53: CPU workaround for 1530924 was applied |
| INFO: BL31: Preparing for EL3 exit to normal world |
| INFO: Entry point address = 0x8f600000 |
| INFO: SPSR = 0x3c9 |
| |
| U-Boot 2021.10 (Dec 01 2021 - 20:00:00 +0000) |
| Qualcomm-DragonBoard 410C |
| ... |
| |
| AArch32 (BL32/SP_MIN) |
| ^^^^^^^^^^^^^^^^^^^^^ |
| BL32/SP_MIN prints some lines on the debug console, which will usually look like |
| this (with ``DEBUG=1``, otherwise only the ``NOTICE`` lines are shown):: |
| |
| ... |
| S - DDR Frequency, 400 MHz |
| NOTICE: SP_MIN: v2.8(debug):v2.8 |
| NOTICE: SP_MIN: Built : 23:03:31, Mar 31 2023 |
| INFO: SP_MIN: Platform setup start |
| INFO: ARM GICv2 driver initialized |
| INFO: SP_MIN: Platform setup done |
| INFO: SP_MIN: Initializing runtime services |
| INFO: BL32: cortex_a53: CPU workaround for 819472 was applied |
| INFO: BL32: cortex_a53: CPU workaround for 824069 was applied |
| INFO: BL32: cortex_a53: CPU workaround for 826319 was applied |
| INFO: BL32: cortex_a53: CPU workaround for 827319 was applied |
| INFO: BL32: cortex_a53: CPU workaround for disable_non_temporal_hint was applied |
| INFO: SP_MIN: Preparing exit to normal world |
| INFO: Entry point address = 0x86400000 |
| INFO: SPSR = 0x1da |
| Android Bootloader - UART_DM Initialized!!! |
| [0] welcome to lk |
| ... |
| |
| .. _Snapdragon 210: https://www.qualcomm.com/products/snapdragon-processors-210 |
| .. _Snapdragon 410: https://www.qualcomm.com/products/snapdragon-processors-410 |
| .. _Snapdragon 615: https://www.qualcomm.com/products/snapdragon-processors-615 |
| .. _Snapdragon X5 Modem: https://www.qualcomm.com/products/snapdragon-modems-4g-lte-x5 |
| .. _DragonBoard 410c: https://www.96boards.org/product/dragonboard410c/ |
| .. _Snapdragon 410E Technical Reference Manual: https://developer.qualcomm.com/download/sd410/snapdragon-410e-technical-reference-manual.pdf |
| .. _U-Boot for DragonBoard 410c: https://u-boot.readthedocs.io/en/latest/board/qualcomm/dragonboard410c.html |
| .. _qtestsign: https://github.com/msm8916-mainline/qtestsign |
| .. _tfalkstub: https://github.com/msm8916-mainline/tfalkstub |