linux-kernel - Re: [PATCH 2/2] mmc: sdhci: Quirk for AMD SDHC Device 0x7906

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Date:   Thu, 3 Oct 2019 12:00:37 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Raul E Rangel <rrangel@...omium.org>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] mmc: sdhci: Quirk for AMD SDHC Device 0x7906

On Wed, 4 Sep 2019 at 18:46, Raul E Rangel <rrangel@...omium.org> wrote:
>
> AMD SDHC 0x7906 requires a hard reset to clear all internal state.
> Otherwise it can get into a bad state where the DATA lines are always
> read as zeros.
>
> This change requires firmware that can transition the device into
> D3Cold for it to work correctly. If the firmware does not support
> transitioning to D3Cold then the power state transitions are a no-op.
>
> Signed-off-by: Raul E Rangel <rrangel@...omium.org>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
> Acked-by: Adrian Hunter <adrian.hunter@...el.com>

Applied for next, thanks!

Kind regards
Uffe


> ---
> This is just a resend of https://patchwork.kernel.org/patch/10925467/
>
>
>  drivers/mmc/host/sdhci-pci-core.c | 51 ++++++++++++++++++++++++++++++-
>  1 file changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-pci-core.c b/drivers/mmc/host/sdhci-pci-core.c
> index 7d06e2860c36..84931ebe0c93 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -21,6 +21,7 @@
>  #include <linux/mmc/mmc.h>
>  #include <linux/scatterlist.h>
>  #include <linux/io.h>
> +#include <linux/iopoll.h>
>  #include <linux/gpio.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/mmc/slot-gpio.h>
> @@ -1590,11 +1591,59 @@ static int amd_probe(struct sdhci_pci_chip *chip)
>         return 0;
>  }
>
> +static u32 sdhci_read_present_state(struct sdhci_host *host)
> +{
> +       return sdhci_readl(host, SDHCI_PRESENT_STATE);
> +}
> +
> +void amd_sdhci_reset(struct sdhci_host *host, u8 mask)
> +{
> +       struct sdhci_pci_slot *slot = sdhci_priv(host);
> +       struct pci_dev *pdev = slot->chip->pdev;
> +       u32 present_state;
> +
> +       /*
> +        * SDHC 0x7906 requires a hard reset to clear all internal state.
> +        * Otherwise it can get into a bad state where the DATA lines are always
> +        * read as zeros.
> +        */
> +       if (pdev->device == 0x7906 && (mask & SDHCI_RESET_ALL)) {
> +               pci_clear_master(pdev);
> +
> +               pci_save_state(pdev);
> +
> +               pci_set_power_state(pdev, PCI_D3cold);
> +               pr_debug("%s: power_state=%u\n", mmc_hostname(host->mmc),
> +                       pdev->current_state);
> +               pci_set_power_state(pdev, PCI_D0);
> +
> +               pci_restore_state(pdev);
> +
> +               /*
> +                * SDHCI_RESET_ALL says the card detect logic should not be
> +                * reset, but since we need to reset the entire controller
> +                * we should wait until the card detect logic has stabilized.
> +                *
> +                * This normally takes about 40ms.
> +                */
> +               readx_poll_timeout(
> +                       sdhci_read_present_state,
> +                       host,
> +                       present_state,
> +                       present_state & SDHCI_CD_STABLE,
> +                       10000,
> +                       100000
> +               );
> +       }
> +
> +       return sdhci_reset(host, mask);
> +}
> +
>  static const struct sdhci_ops amd_sdhci_pci_ops = {
>         .set_clock                      = sdhci_set_clock,
>         .enable_dma                     = sdhci_pci_enable_dma,
>         .set_bus_width                  = sdhci_set_bus_width,
> -       .reset                          = sdhci_reset,
> +       .reset                          = amd_sdhci_reset,
>         .set_uhs_signaling              = sdhci_set_uhs_signaling,
>  };
>
> --
> 2.23.0.187.g17f5b7556c-goog
>