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

[Pali Rohár]

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.

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