IMX8MM fsl_esdhc_imx UHS/HS200/HS400 not working?

IMX8MM fsl_esdhc_imx UHS/HS200/HS400 not working?

[Tim Harvey]

Greetings,

Can anyone confirm if IMX8MM UHS/HS200/HS400 is working for them? I
had this working in my U-Boot v2021.01 imx8mm-veice branch but it
seems to not work in U-Boot master or v2021.07. I know there was a lot
of back and forth on this... perhaps I missed something. I haven't
been able to bisect yet as I had a lot of patches on top of my
v2021.01 branch.

Best regards,

Tim

Re: IMX8MM fsl_esdhc_imx UHS/HS200/HS400 not working?

[Tim Harvey]

On Thu, Sep 16, 2021 at 4:32 PM Tim Harvey <tharvey@gateworks.com> wrote:
>
> Greetings,
>
> Can anyone confirm if IMX8MM UHS/HS200/HS400 is working for them? I
> had this working in my U-Boot v2021.01 imx8mm-veice branch but it
> seems to not work in U-Boot master or v2021.07. I know there was a lot
> of back and forth on this... perhaps I missed something. I haven't
> been able to bisect yet as I had a lot of patches on top of my
> v2021.01 branch.
>

It looks to me like I was mistaken and we still don't have enough
support upstream for IMX8MM UHS/HS200/HS400 to work.

The following are still needed:
[1] fsl_esdhc_imx: Use esdhc_soc_data flags to set host caps
- Adam submitted this some time ago which is required to set the
IMX8MM MMC host capabilities such that UHS/HS200/HS400 are supported
- it was never merged due to some uncertainty that everything was
working with those modes.
[2] mmc: fsl_esdhc_imx: use VENDORSPEC_FRC_SDCLK_ON to control card clock output
- this was merged but later reverted [3] due to it causing a
regression of extremely slow MMC in SPL/U-Boot on imx6qdl-pico for
unknown reasons

That said, even though I had UHS/HS200/HS400/HS400ES support in my
v2021.01 branch I ran into the following issues and ended up disabing
HS200/HS400/HS400ES (but kept UHS enabled):
- occasional failures with 'mmc init <emmcdev>' (nothing printed but
an error code returned causing bootscripts to fail to boot to Linux
- failures with eMMC parts that supported eMMC 5.1 HS400ES unless I
disabled HS400ES (can't recall the exact failure and don't have a
board handy to test with)

I'm going to kick off some testing to see if the above issues are
still occuring with patch [1] and [2] on u-boot master.

Anyone else have some feedback regarding UHS/HS200/HS400/HS400ES on IMX8MM?

Best regards,

Tim
[1] https://lists.denx.de/pipermail/u-boot/2020-December/436386.html
[2] https://lists.denx.de/pipermail/u-boot/2021-March/443018.html
[3] https://lists.denx.de/pipermail/u-boot/2021-June/451601.html