linux-kernel - Re: [PATCH V1 1/2] mmc: sdhci: Introduce new quirk to use reserved timeout

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Date:   Mon, 18 May 2020 11:39:07 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Sarthak Garg <sartgarg@...eaurora.org>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        Veerabhadrarao Badiganti <vbadigan@...eaurora.org>,
        Sahitya Tummala <stummala@...eaurora.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH V1 1/2] mmc: sdhci: Introduce new quirk to use reserved timeout

On Wed, 6 May 2020 at 15:53, Sarthak Garg <sartgarg@...eaurora.org> wrote:
>
> Introduce a new quirk for letting vendor drivers to use reserved
> timeout value (0xF) in timeout control register.
>
> Signed-off-by: Sahitya Tummala <stummala@...eaurora.org>
> Signed-off-by: Sarthak Garg <sartgarg@...eaurora.org>
> ---
>  drivers/mmc/host/sdhci.c | 3 ++-
>  drivers/mmc/host/sdhci.h | 5 +++++
>  2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 1bb6b67..07528a9 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -967,7 +967,8 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd,
>         }
>
>         if (count >= 0xF) {
> -               if (!(host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT))
> +               if (!(host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT) ||
> +               !(host->quirks2 & SDHCI_QUIRK2_USE_RESERVED_MAX_TIMEOUT))

I don't quite get how this can make your variant use 0xF rather than 0xE?

To me it looks like an updated conditional check to print a debug message, no?

>                         DBG("Too large timeout 0x%x requested for CMD%d!\n",
>                             count, cmd->opcode);
>                 count = 0xE;
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 8d2a096..02f8779 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -476,6 +476,11 @@ struct sdhci_host {
>   * block count.
>   */
>  #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT                 (1<<18)
> +/*
> + * Some controllers define the usage of 0xF in data timeout counter
> + * register (0x2E) which is actually a reserved bit as per specification.
> + */
> +#define SDHCI_QUIRK2_USE_RESERVED_MAX_TIMEOUT          (1<<19)
>
>         int irq;                /* Device IRQ */
>         void __iomem *ioaddr;   /* Mapped address */
> --
> 2.7.4
>

Kind regards
Uffe