linux-kernel - Re: [PATCH] mmc: sdhci: Fix warning message when accessing RPMB in HS400 mode

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Date:   Wed, 30 Jun 2021 16:20:26 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Al Cooper <alcooperx@...il.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        linux-mmc <linux-mmc@...r.kernel.org>
Subject: Re: [PATCH] mmc: sdhci: Fix warning message when accessing RPMB in
 HS400 mode

On Thu, 24 Jun 2021 at 18:31, Al Cooper <alcooperx@...il.com> wrote:
>
> When an eMMC device is being run in HS400 mode, any access to the
> RPMB device will cause the error message "mmc1: Invalid UHS-I mode
> selected". This happens as a result of tuning being disabled before
> RPMB access and then re-enabled after the RPMB access is complete.
> When tuning is re-enabled, the system has to switch from HS400
> to HS200 to do the tuning and then back to HS400. As part of
> sequence to switch from HS400 to HS200 the system is temporarily
> put into HS mode. When switching to HS mode, sdhci_get_preset_value()
> is called and does not have support for HS mode and prints the warning
> message and returns the preset for SDR12. The fix is to add support
> for MMC and SD HS modes to sdhci_get_preset_value().
>
> This can be reproduced on any system running eMMC in HS400 mode
> (not HS400ES) by using the "mmc" utility to run the following
> command: "mmc rpmb read-counter /dev/mmcblk0rpmb".
>
> Signed-off-by: Al Cooper <alcooperx@...il.com>

I assume we want this for stable kernels, but it would be nice to add
a fixes tag as well.

Do you know if there is a specific commit that this fixes?

Kind regards
Uffe

> ---
>  drivers/mmc/host/sdhci.c | 4 ++++
>  drivers/mmc/host/sdhci.h | 1 +
>  2 files changed, 5 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index bf238ade1602..6b39126fbf06 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1812,6 +1812,10 @@ static u16 sdhci_get_preset_value(struct sdhci_host *host)
>         u16 preset = 0;
>
>         switch (host->timing) {
> +       case MMC_TIMING_MMC_HS:
> +       case MMC_TIMING_SD_HS:
> +               preset = sdhci_readw(host, SDHCI_PRESET_FOR_HIGH_SPEED);
> +               break;
>         case MMC_TIMING_UHS_SDR12:
>                 preset = sdhci_readw(host, SDHCI_PRESET_FOR_SDR12);
>                 break;
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 0770c036e2ff..960fed78529e 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -253,6 +253,7 @@
>
>  /* 60-FB reserved */
>
> +#define SDHCI_PRESET_FOR_HIGH_SPEED    0x64
>  #define SDHCI_PRESET_FOR_SDR12 0x66
>  #define SDHCI_PRESET_FOR_SDR25 0x68
>  #define SDHCI_PRESET_FOR_SDR50 0x6A
>
> base-commit: 7426cedc7dad67bf3c71ea6cc29ab7822e1a453f
> --
> 2.17.1
>