[EXT] [PATCH] ARM: imx: romapi: Repair FlexSPI NOR boot offset

[Marek Vasut]

On 3/31/22 17:09, Tim Harvey wrote:
> On Mon, Mar 28, 2022 at 7:55 AM Marek Vasut <marex at denx.de> wrote:
>>
>> On 3/28/22 08:54, Ye Li wrote:
>>> Hi Marek,
>>
>> Hi,
>>
>> [...]
>>
>>>>> 2. Update the u-boot.itb offset in imx8mp-u-boot.dtsi, set the
>>>>> offset
>>>>> to 0x5f000.  The previous offset 0x58000 is for SD, calculated by
>>>>> 0x60000 - 0x8000 (32KB image offset).
>>>>>
>>>>>                 uboot: blob-ext at 2 {
>>>>>                         filename = "u-boot.itb";
>>>>>                         offset = <0x5f000>;
>>>>>                 };
>>>> But that breaks booting from SD card for me ?
>>>
>>> Do you want to use one flash.bin for both SD and flexspi?
>>
>> Yes, the board I use can boot from SD/eMMC/FlexSPI. I don't want to
>> build multiple confusing "flash.bin" files, one for each boot media.
>>
>>> When first introduced 8m support by imx8mimage.c, we expected the u-
>>> boot.itb at same device offset (0x60000) on SD/emmc and flexspi. The
>>> imx8mimage will calculate the offset inside the flash.bin automatically
>>> according to different IVT offset. The ROMAPI driver also works
>>> correspondingly.
>>> After using binman, the u-boot.itb offset inside the flash.bin has to
>>> be manually set in this DTS node. To follow the original design, this
>>> offset should be different. That's why I asked to update this dts node
>>> for flexspi.
>>
>> This does imply that there are currently no users that boot from flexspi
>> in upstream U-Boot, because such users would have to manually modify
>> both arch/arm/dts/imx8m?-u-boot.dtsi and board/*/imximage.cfg to
>> generate suitable flash.bin which can be started from FlexSPI.
>>
>> Also, git grep confirms that there are no users:
>>
>> u-boot$ git grep BOOT_FROM.*fspi
>> doc/imx/mkimage/imx8image.txt:BOOT_FROM
>> [sd|emmc_fastboot|fspi|nand_4k|nand_8k|nand_16k] [sector_size]
>>
>>> If you change the ROM API driver, that will break our design. You can
>>> try to overwrite spl_romapi_get_uboot_base for your board only.
>>
>> Since there are no users which boot from flexspi upstream, this design
>> can still be fixed such that it does not require different flash.bin for
>> different boot media, but rather one flash.bin works on all boot media.
>> I think that is much better.
>>
> 
> Marek,
> 
> I'm also a fan of single U-Boot binaries supporting multiple boards
> and configurations.
> 
> How are you handling env for the various boot devices? I haven't
> looked in a while... can multiple env support co-exist now between
> MMC/SPI and be selected at runtime?

Do '$ git grep env_get_location' , you will find board-level examples 
where this function is implemented and it returns ENVL_* based on 
various hardware-specific conditions.

I _think_ there is even imx arch specific implementation for this 
env_get_location() which automatically picks SD/eMMC/FlexSPI for you 
right now.