[PATCH 2/2] arm: mvebu: clearfog: Add defconfig for SPI booting

[Tony Dinh]

Hi Pali,
Hi Martin,

On Sat, Feb 25, 2023 at 5:41 AM Pali Rohár <pali at kernel.org> wrote:
>
> On Saturday 25 February 2023 11:47:07 Martin Rowe wrote:
> > > While I haven't tested this patchset - I have tested SPI booting with v2022.01 after applying lots of patches.
> > > I found that the magic value reported by bootrom when booting from SPI will be 0x34 on clearfog.
> > > The current sources only handle 0x32, hence having or not having SPL_SPI will always lead to returning to the bootrom.
> > >
> > > Please consider pulling in this patch:
> > > https://github.com/SolidRun/u-boot/commit/f4f8a69740a8415c05359e01e51650f445cda03d
> > > I can send it separately if you like.
> >
> > Tested with the patch on a Clearfog Base:
> > ================== Without SPL_SPI same return to BootROM
> > ...
> > mv_ddr: completed successfully
> > Trying to boot from BOOTROM
> > Returning to BootROM (return address 0xffff05c4)...
> > BootROM: Image checksum verification PASSED
> >
> >
> > U-Boot 2023.04-rc2...
> > ================== With SPL_SPI loads directly from SPI
> > ...
> > mv_ddr: completed successfully
> > Trying to boot from SPI
> >
> >
> > U-Boot 2023.04-rc2...
> > ==================
> >
> > I'm not sure how to run proper timing tests on the process, but
> > stopwatch timing just between seeing "Trying to boot" and "U-Boot
> > 2023.04-rc2" showed the return to BootROM under 1 second, and the
> > direct from SPI around 4 seconds. I thought the goal of loading from
> > SPI directly was speed, but returning to BootROM is significantly
> > faster on this board.
>
> You should check SPI speed in DTS file and also in the defconfig.

I think we have probably seen this slowdown before. There is a TODO in
the way the DTS nodes are parsed by DM uclass. So this config must be
set in defconfig to get around that bug:
CONFIG_SF_DEFAULT_SPEED=50000000

All the best,
Tony
>
> > > which I have tested by adding these config options:
> >
> > I tested the new spi_defconfig with and without SPL_SPI; no other changes