feat(rpi): add Raspberry Pi 5 support
The Raspberry Pi 5 is a single-board computer based on BCM2712 that
contains four Arm Cortex-A76 cores.
This change introduces minimal BL31 support with PSCI that has been
validated to boot Linux and a private EDK2 build.
It's a drop-in replacement for the custom TF-A armstub now included in
the EEPROM images.
Change-Id: Id72a0370f54e71ac97c3daa1bacedacb7dec148f
Signed-off-by: Mario Bălănică <mariobalanica02@gmail.com>
diff --git a/docs/plat/index.rst b/docs/plat/index.rst
index b1ccaa5..795fb09 100644
--- a/docs/plat/index.rst
+++ b/docs/plat/index.rst
@@ -37,6 +37,7 @@
qti-msm8916
rpi3
rpi4
+ rpi5
rcar-gen3
rz-g2
rockchip
diff --git a/docs/plat/rpi5.rst b/docs/plat/rpi5.rst
new file mode 100644
index 0000000..f2e1b9f
--- /dev/null
+++ b/docs/plat/rpi5.rst
@@ -0,0 +1,78 @@
+Raspberry Pi 5
+==============
+
+The `Raspberry Pi 5`_ is a single-board computer that contains four
+Arm Cortex-A76 cores.
+
+This port is a minimal BL31 implementation capable of booting 64-bit EL2
+payloads such as Linux and EDK2.
+
+**IMPORTANT NOTE**: This port isn't secure. All of the memory used is DRAM,
+which is available from both the Non-secure and Secure worlds. The SoC does
+not seem to feature a secure memory controller of any kind, so portions of
+DRAM can't be protected properly from the Non-secure world.
+
+Build
+------------------
+
+To build this platform, run:
+
+.. code:: shell
+
+ CROSS_COMPILE=aarch64-linux-gnu- make PLAT=rpi5 DEBUG=1
+
+The firmware will be generated at ``build/rpi5/debug/bl31.bin``.
+
+The following build options are supported:
+
+- ``RPI3_DIRECT_LINUX_BOOT``: Enabled by default. Allows direct boot of the Linux
+ kernel from the firmware.
+
+- ``PRELOADED_BL33_BASE``: Used to specify the fixed address of a BL33 binary
+ that has been preloaded by earlier boot stages (VPU). Useful for bundling
+ BL31 and BL33 in the same ``armstub`` image (e.g. TF-A + EDK2).
+
+- ``RPI3_PRELOADED_DTB_BASE``: This option allows to specify the fixed address of
+ a DTB in memory. Can only be used if ``device_tree_address=`` is present in
+ config.txt.
+
+- ``RPI3_RUNTIME_UART``: Indicates whether TF-A should use the debug UART for
+ runtime messages or not. ``-1`` (default) disables the option, any other value
+ enables it.
+
+Usage
+------------------
+
+Copy the firmware binary to the first FAT32 partition of a supported boot media
+(SD, USB) and append ``armstub=bl31.bin`` to config.txt, or just rename the
+file to ``armstub8-2712.bin``.
+
+No other config options or files are required by the firmware alone, this will
+depend on the payload you intend to run.
+
+For Linux, you must also place an appropriate DTB and kernel in the boot
+partition. This has been validated with a copy of Raspberry Pi OS.
+
+The VPU will preload a BL33 AArch64 image named either ``kernel_2712.img`` or
+``kernel8.img``, which can be overridden by adding a ``kernel=filename`` option
+to config.txt.
+
+Kernel and DTB load addresses are also chosen by the VPU and can be changed with
+``kernel_address=`` and ``device_tree_address=`` in config.txt. If TF-A was built
+with ``PRELOADED_BL33_BASE`` or ``RPI3_PRELOADED_DTB_BASE``, setting those config
+options may be necessary.
+
+By default, all boot stages print messages to the dedicated UART debug port.
+Configuration is ``115200 8n1``.
+
+Design
+------------------
+
+This port is largely based on the RPi 4 one.
+
+The boot process is essentially the same, the only notable difference being that
+all VPU blobs have been moved into EEPROM (former start4.elf & fixup4.dat). There's
+also a custom BL31 TF-A armstub included for PSCI, which can be replaced with this
+port.
+
+.. _Raspberry Pi 5: https://www.raspberrypi.com/products/raspberry-pi-5/