Hi Peng,
On 24/01/2016 14:04, Peng Fan wrote:
I agree with Otavio that this is a very nasty hack, and the hardware developer should provide a way getting the board revision. Anyway, I would not certainly block it, as it concerns just this board, but I ask if it is not better to let decide to an environment variable if eMMC must be activated. Advantage is to have a single U-Boot binary for both boards, disadvantage is that it coul be set for the wrong board revision, too. But if USDHC4 was not used anymore, this drives just to a not found eMMC. Both ways are hacks, I fully agree, but CONFIG_MX6SXSABRESD_EMMC_REWORK remains undocumented at all, too.
What do you think ?
There is no fuse bit or else to let uboot do runtime checking. I also disklike this, but I do not have a better idea. Without runtime checking, it's hard to use one image support SD/EMMC both. I would like to add doc for the macro CONFIG_MX6SXSABRESD_EMMC_REWORK in the next version, do you agree with this?
I add Fabio as he is the board maintainer for mx6sxsabresd.
If adding the #ifdef remains the preferred solution instead of checkin an env variable, it should be done that it does not generate dead code as the current patch. That means that a defconfig file must be added into configs, where CONFIG_MX6SXSABRESD_EMMC_REWORK is set. Else the code is never built by running buildman and breakages cannot be detected.
Anyway, there are already two files for the board, mx6sxsabresd_defconfig and mx6sxsabresd_spl_defconfig, and if you want to have for this board revision both U-Boot with and without SPL, two additional files are needed - it does not scale very well.
Best regards, Stefano Babic