[PATCH] mmc: allow forward compatibility for EXT_CSD_REV

[박민우 (MW Park)]

>Would this patch works for you?
>https://lore.kernel.org/u-boot/20260225211332.1896252-1-han.xu@nxp.com/

>Regards,
>Peng

Thank you for your feedback.

I would like to clarify that I independently developed and verified a similar approach to the one in the linked patch. However, my analysis shows that the linked patch is primarily focused on v5.1B, which may lead to compatibility issues with future eMMC versions.

I believe my proposed patch provides a more generalized and future-proof solution, ensuring long-term maintenance and stability regardless of version updates.

Please let me know your thoughts on this approach.

Thanks,
Best Regards,
MW Park.

________________________________________
보낸 사람: Peng Fan <peng.fan at oss.nxp.com>
보낸 날짜: 2026년 4월 9일 목요일 오전 1:21
받는 사람: 박민우 (MW Park)
참조: u-boot at lists.denx.de; peng.fan at nxp.com; jh80.chung at samsung.com
제목: Re: [PATCH] mmc: allow forward compatibility for EXT_CSD_REV

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On Thu, Mar 26, 2026 at 05:55:32AM +0000, ?????? (MW Park) wrote:
>According to the JEDEC Standard, the EXT_CSD format is meant to be
>forward compatible. As long as CSD_STRUCTURE does not change, all
>values for EXT_CSD_REV are authorized.
>
>Currently, if an eMMC device with a newer EXT_CSD_REV (e.g., eMMC 5.1B
>with EXT_CSD_REV=9) is used, U-Boot fails to initialize it and returns
>-EINVAL because the revision is larger than the mmc_versions array size.
>
>Fix this by falling back to the latest supported version if the
>EXT_CSD_REV exceeds the known versions. This ensures forward
>compatibility with future eMMC specifications.
>
>Signed-off-by: MW Park <mw.park at telechips.com>

Would this patch works for you?
https://lore.kernel.org/u-boot/20260225211332.1896252-1-han.xu@nxp.com/

Regards,
Peng
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