[U-Boot] [PATCH 2/2] ARM: add Raspberry Pi 3 64-bit config

Tom Rini trini at konsulko.com
Sat Apr 2 15:26:04 CEST 2016


On Fri, Apr 01, 2016 at 09:14:15PM -0600, Stephen Warren wrote:

> On all Pis so far, the VC FW provides a short stub to set up the ARM CPU
> before entering the kernel (a/k/a U-Boot for us). This feature is not
> currently supported by the VC FW when booting in 64-bit mode. However,
> this feature will likely appear in the near future, and this U-Boot port
> assumes that such a feature is in place. Without that feature, or a
> temporary workaround described below, U-Boot will not boot.
> 
> Once the VC FW does provide the ARM stub, u-boot.bin built for rpi_3 can
> be used drectly as kernel7.img, in the same way as any other RPi port. The
> following config.txt is required:
> 
>     # Fix mini UART input frequency, and setup/enable up the UART.
>     # Without this option, U-Boot will not boot, even if you don't care
>     # about the serial console. This option will always be required for
>     # all RPi3 use-cases, unless the PL011 UART is used, which is not
>     # yet supported by rpi_3* builds of U-Boot.
>     enable_uart=1
>     # Boot in AArch64 (64-bit) mode.
>     # It is possible that a future VC FW will remove the need for this
>     # option, instead auto-setting 32-/64-bit mode based on the "kernel"
>     # filename present on the SD card.
>     arm_control=0x200
> 
> Prior to the VC FW providing the ARM boot stub, you can use the following
> steps to build an equivalent stub into the U-Boot binary:
> 
> git clone https://github.com/swarren/rpi-3-aarch64-demo.git \
>     ../rpi-3-aarch64-demo
> (cd ../rpi-3-aarch64-demo && ./build.sh)
> Build U-Boot for rpi_3 in the usual way
> cat ../rpi-3-aarch64-demo/armstub64.bin u-boot.bin > u-boot.bin.stubbed
> Use u-boot.bin.stubbed as kernel7.img on the Pi SD card.
> 
> In this case, the following additional entries are required in config.txt:
> 
>     # Tell the FW to load the kernel image at address 0, the reset vector.
>     kernel_old=1
> 
> Signed-off-by: Stephen Warren <swarren at wwwdotorg.org>

As our infrastructure stands today:
Reviewed-by: Tom Rini <trini at konsulko.com>

But would it be possible to clean things up and consolidate files?  If
CONFIG_SYS_CACHLINE_SIZE and CONFIG_SKIP_LOWLEVEL_INIT were in Kconfig
it looks like everything could live in board/raspberrypi/rpi/ which it
nearly does today.  If it's hard, I'd be OK punting that to v2015.07.
Or am I missing something?

-- 
Tom
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