linux-kernel - Re: [PATCH] mmc: core: Disable card detect during shutdown

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Message-ID: <CAPDyKFqGSq=OMd_0N=okQk12Tiy=eyW+S26=tSx8r4poSStdcA@mail.gmail.com>
Date:   Fri, 3 Dec 2021 15:20:16 +0100
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     linux-mmc@...r.kernel.org, Ulf Hansson <ulf.hansson@...aro.org>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Al Cooper <alcooperx@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] mmc: core: Disable card detect during shutdown

On Fri, 3 Dec 2021 at 15:16, Ulf Hansson <ulf.hansson@...aro.org> wrote:
>
> It's seems prone to problems by allowing card detect and its corresponding
> mmc_rescan() work to run, during platform shutdown. For example, we may end
> up turning off the power while initializing a card, which potentially could
> damage it.
>
> To avoid this scenario, let's add ->shutdown_pre() callback for the mmc host
> class device and then turn of the card detect from there.
>
> Signed-off-by: Al Cooper <alcooperx@...il.com>

Sorry, I was intending to make this a "Reported-by:" tag.

And I should have added Adrian's suggested-by tag too. Sorry.

> Cc: stable@...r.kernel.org
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> ---
>  drivers/mmc/core/core.c | 7 ++++++-
>  drivers/mmc/core/core.h | 1 +
>  drivers/mmc/core/host.c | 9 +++++++++
>  3 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 240c5af793dc..368f10405e13 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2264,7 +2264,7 @@ void mmc_start_host(struct mmc_host *host)
>         _mmc_detect_change(host, 0, false);
>  }
>
> -void mmc_stop_host(struct mmc_host *host)
> +void __mmc_stop_host(struct mmc_host *host)
>  {
>         if (host->slot.cd_irq >= 0) {
>                 mmc_gpio_set_cd_wake(host, false);
> @@ -2273,6 +2273,11 @@ void mmc_stop_host(struct mmc_host *host)
>
>         host->rescan_disable = 1;
>         cancel_delayed_work_sync(&host->detect);
> +}
> +
> +void mmc_stop_host(struct mmc_host *host)
> +{
> +       __mmc_stop_host(host);
>
>         /* clear pm flags now and let card drivers set them as needed */
>         host->pm_flags = 0;
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index 7931a4f0137d..f5f3f623ea49 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -70,6 +70,7 @@ static inline void mmc_delay(unsigned int ms)
>
>  void mmc_rescan(struct work_struct *work);
>  void mmc_start_host(struct mmc_host *host);
> +void __mmc_stop_host(struct mmc_host *host);
>  void mmc_stop_host(struct mmc_host *host);
>
>  void _mmc_detect_change(struct mmc_host *host, unsigned long delay,
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index d4683b1d263f..cf140f4ec864 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -80,9 +80,18 @@ static void mmc_host_classdev_release(struct device *dev)
>         kfree(host);
>  }
>
> +static int mmc_host_classdev_shutdown(struct device *dev)
> +{
> +       struct mmc_host *host = cls_dev_to_mmc_host(dev);
> +
> +       __mmc_stop_host(host);
> +       return 0;
> +}
> +
>  static struct class mmc_host_class = {
>         .name           = "mmc_host",
>         .dev_release    = mmc_host_classdev_release,
> +       .shutdown_pre   = mmc_host_classdev_shutdown,
>         .pm             = MMC_HOST_CLASS_DEV_PM_OPS,
>  };
>
> --
> 2.25.1
>