Re: [PATCH] arm: Add (back) VExpress boards support

On Tue, Jun 29, 2021 at 12:45:55PM +0100, Andre Przywara wrote:

The v2021.07 merge window saw the removal of the Arm Ltd. Versatile
Express platform, along with their CA5, CA9 and TC2 boards. The trigger
was the missing conversion of the MMC driver.

Some folks complained about that internally, so bring those boards back,
but better than ever:
- Use DM and OF_CONTROL for all the boards. Use the .dts files from the
  latest Linux kernel (5.13) for that.
- Move the board selection choice into the platform's Kconfig.
- Clean up some shared config and common definitions.
- Drop obsolete features like ATAGs support.
- Switch to the DM_ETH version of the SMC911X Ethernet driver.
- Drop MMC support.

The PL180 MMC driver actually supports DM_MMC, but that requires a
DM_GPIO driver for the card detect GPIO, which we don't have. This
specific GPIO is actually handled via the "sysregs" device, so we would
need a driver for that. QEMU does not emulate this part, also the DT
description is somewhat "special", so this is left for later.

This version compiles without any warning for all three boards now.
Tested on QEMU.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
---
Hi,

this relies on the SMC911x driver DT changes, as posted here:
https://lists.denx.de/pipermail/u-boot/2021-June/452989.html
I put a version with the changes broken down here:
https://github.com/Andre-ARM/u-boot/commits/tc2-history

This was tested on QEMU, for vexpress_ca15_tc2_defconfig with:
$ qemu-system-arm -M vexpress-a15,secure=on -cpu cortex-a15 -m 1G -smp 1 \
  -drive file=tramp-tc2.bin,if=pflash,format=raw,read-only \
  -device loader,file=u-boot.bin,addr=0x80800000 -nographic

Where tramp-tc2.bin is a trampoline replacing the board's firmware:
00000000  00 00 a0 e3 80 00 48 e3  10 ff 2f e1
(mov r0, #0; movt r0, #0x8080; bx r0)

The vexpress_ca9x4_defconfig uses a different memory map, so the runes are:
$ qemu-system-arm -M vexpress-a9 -cpu cortex-a9 -m 1G -smp 1 \
  -drive file=tramp-ca9.bin,if=pflash,format=raw,read-only \
  -device loader,file=u-boot.bin,addr=0x60800000 -nographic

tramp-ca9.bin:
00000000  00 00 a0 e3 80 00 46 e3  10 ff 2f e1
(mov r0, #0; movt r0, #0x6080; bx r0)

My big question is how do we run this in CI?  Or does it not _need_ that
firmware file to really exist?  Or is there a pending change to
https://gitlab.denx.de/u-boot/u-boot-test-hooks.git to generate / just
have exist those magic empty bins?  Thanks!

-- 
Tom