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

[Ye Li]

On Mon, 2022-03-28 at 16:54 +0200, Marek Vasut wrote:
> Caution: EXT Email
> 
> 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.

Your flash.bin can work on flexspi because you manually program the
flexspi configurations header.  But once you want to upgrade the
flash.bin, flexspi configurations will also be erased due to the block
size. Then you have to reprogram the configurations with flash.bin.
So most of our customers add the flexspi configurations to flash.bin
head. They don't use so called one image for both SD and flexspi. 

As the spl_romapi_get_uboot_base is defined to weak. It is better to
overwrite this function for your particular usage.

Best regards,
Ye Li
> 
> [...]