Re: [PATCH v2] mmc: core: Introduce MMC_CAP2_NO_SDIO cap

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On 25 November 2015 at 15:39, Carlo Caione <carlo@xxxxxxxxxx> wrote:
> From: Carlo Caione <carlo@xxxxxxxxxxxx>
>
> This patch introduce a new MMC_CAP2_NO_SDIO cap used to tell the mmc
> core to not send SDIO specific commands.

I guess there are two reasons to why such capability is useful.
1) The host controller/driver doesn't support SDIO.
2) There is an embedded/non-removable eMMC/SD card.

Within that context, we might also want to add MMC_CAP2_NO_MMC|SD, or
what do you think?

Because of 2), we might also want to add a new mmc DT binding or
perhaps try interpret a combination of them to enable
MMC_CAP2_NO_SDIO!?

>
> Signed-off-by: Carlo Caione <carlo@xxxxxxxxxxxx>

Thanks, applied for next!

Kind regards
Uffe

> ---
>
> Drivers fix will follow.
>
> Changelog:
>
> * v2:
>    - moved check from __mmc_start_request to mmc_rescan_try_freq
>
> ---
>  drivers/mmc/core/core.c  | 11 ++++++++---
>  include/linux/mmc/host.h |  1 +
>  2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 5ae89e4..8a4e0d2 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2476,15 +2476,20 @@ static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
>          * sdio_reset sends CMD52 to reset card.  Since we do not know
>          * if the card is being re-initialized, just send it.  CMD52
>          * should be ignored by SD/eMMC cards.
> +        * Skip it if we already know that we do not support SDIO commands
>          */
> -       sdio_reset(host);
> +       if (!(host->caps2 & MMC_CAP2_NO_SDIO))
> +               sdio_reset(host);
> +
>         mmc_go_idle(host);
>
>         mmc_send_if_cond(host, host->ocr_avail);
>
>         /* Order's important: probe SDIO, then SD, then MMC */
> -       if (!mmc_attach_sdio(host))
> -               return 0;
> +       if (!(host->caps2 & MMC_CAP2_NO_SDIO))
> +               if (!mmc_attach_sdio(host))
> +                       return 0;
> +
>         if (!mmc_attach_sd(host))
>                 return 0;
>         if (!mmc_attach_mmc(host))
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 8673ffe..cf6d0bb 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -289,6 +289,7 @@ struct mmc_host {
>  #define MMC_CAP2_HSX00_1_2V    (MMC_CAP2_HS200_1_2V_SDR | MMC_CAP2_HS400_1_2V)
>  #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17)
>  #define MMC_CAP2_NO_WRITE_PROTECT (1 << 18)    /* No physical write protect pin, assume that card is always read-write */
> +#define MMC_CAP2_NO_SDIO       (1 << 19)       /* Do not send SDIO commands during initialization */
>
>         mmc_pm_flag_t           pm_caps;        /* supported pm features */
>
> --
> 2.5.0
>
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