Re: [PATCH v3] mmc: mediatek: Add MMC_CAP_SDIO_IRQ support

[Ulf Hansson]

On Mon, 10 Dec 2018 at 12:44, Jjian Zhou <jjian.zhou@xxxxxxxxxxxx> wrote:
>
> From: jjian zhou <jjian.zhou@xxxxxxxxxxxx>
>
> This patch enables support SDIO IRQs. It enables
> MMC_CAP_SDIO_IRQ & MMC_CAP2_SDIO_IRQ_NOTHREAD
> and implement the ->ack_sdio_irq callback.
>
> Signed-off-by: Jjian Zhou <jjian.zhou@xxxxxxxxxxxx>
> Signed-off-by: Chaotian Jing <chaotian.jing@xxxxxxxxxxxx>
> Signed-off-by: Yong Mao <yong.mao@xxxxxxxxxxxx>
> ---
>  drivers/mmc/host/mtk-sd.c | 49 ++++++++++++++++++++++++++++++++++++++++++++---
>  1 file changed, 46 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index 6334cc7..40a1848 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -1114,6 +1114,7 @@ static void msdc_start_command(struct msdc_host *host,
>                 struct mmc_request *mrq, struct mmc_command *cmd)
>  {
>         u32 rawcmd;
> +       unsigned long flags;
>
>         WARN_ON(host->cmd);
>         host->cmd = cmd;
> @@ -1131,7 +1132,10 @@ static void msdc_start_command(struct msdc_host *host,
>         cmd->error = 0;
>         rawcmd = msdc_cmd_prepare_raw_cmd(host, mrq, cmd);
>
> +       spin_lock_irqsave(&host->lock, flags);
>         sdr_set_bits(host->base + MSDC_INTEN, cmd_ints_mask);
> +       spin_unlock_irqrestore(&host->lock, flags);
> +

The above looks like a reasonable change, however does it really
belong in $subject patch. If so, can you explain why?

Maybe you should move this into a standalone separate patch?

>         writel(cmd->arg, host->base + SDC_ARG);
>         writel(rawcmd, host->base + SDC_CMD);
>  }
> @@ -1351,6 +1355,27 @@ static void msdc_request_timeout(struct work_struct *work)
>         }
>  }
>
> +static void msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)
> +{
> +       unsigned long flags;
> +       struct msdc_host *host = mmc_priv(mmc);
> +
> +       if (enb)
> +               pm_runtime_get_sync(host->dev);

I would convert to pm_runtime_get_noresume() as the host is already
been runtime resumed by the mmc core.

> +
> +       spin_lock_irqsave(&host->lock, flags);
> +       if (enb)
> +               sdr_set_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
> +       else
> +               sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
> +       spin_unlock_irqrestore(&host->lock, flags);

You should move the code above into a separate function. Along the lines of:

static void __msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)

You need this, because you will otherwise mess up the runtime PM usage
count when acking the SDIO irq. More comments about that below.

> +
> +       if (!enb) {
> +               pm_runtime_mark_last_busy(host->dev);
> +               pm_runtime_put_autosuspend(host->dev);

Convert to pm_runtime_put_noidle(), as the above is already managed by
the mmc core.

> +       }
> +}
> +
>  static irqreturn_t msdc_irq(int irq, void *dev_id)
>  {
>         struct msdc_host *host = (struct msdc_host *) dev_id;
> @@ -1373,7 +1398,12 @@ static irqreturn_t msdc_irq(int irq, void *dev_id)
>                 data = host->data;
>                 spin_unlock_irqrestore(&host->lock, flags);
>
> -               if (!(events & event_mask))
> +               if ((events & event_mask) & MSDC_INT_SDIOIRQ) {
> +                       msdc_enable_sdio_irq(host->mmc, 0);

To not mess up the runtime PM reference count and to avoid invoking
runtime PM callbacks from atomic context, I suggest you call
__msdc_enable_sdio_irq(host->mmc, 0) (new proposed function according
to earlier comment).

> +                       sdio_signal_irq(host->mmc);
> +               }
> +
> +               if (!(events & (event_mask & ~MSDC_INT_SDIOIRQ)))
>                         break;
>
>                 if (!mrq) {
> @@ -1493,8 +1523,11 @@ static void msdc_init_hw(struct msdc_host *host)
>          */
>         sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIO);
>
> -       /* disable detect SDIO device interrupt function */
> -       sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> +       /* Config SDIO device detect interrupt function */
> +       if (host->mmc->caps & MMC_CAP_SDIO_IRQ)
> +               sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> +       else
> +               sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
>
>         /* Configure to default data timeout */
>         sdr_set_field(host->base + SDC_CFG, SDC_CFG_DTOC, 3);
> @@ -2013,6 +2046,11 @@ static void msdc_hw_reset(struct mmc_host *mmc)
>         sdr_clr_bits(host->base + EMMC_IOCON, 1);
>  }
>
> +static void msdc_ack_sdio_irq(struct mmc_host *mmc)
> +{
> +       msdc_enable_sdio_irq(mmc, 1);

To not mess up the runtime PM reference count, I suggest you call
__msdc_enable_sdio_irq(host->mmc, 1) (new proposed function according
to earlier comment).

> +}
> +
>  static const struct mmc_host_ops mt_msdc_ops = {
>         .post_req = msdc_post_req,
>         .pre_req = msdc_pre_req,
> @@ -2020,6 +2058,8 @@ static void msdc_hw_reset(struct mmc_host *mmc)
>         .set_ios = msdc_ops_set_ios,
>         .get_ro = mmc_gpio_get_ro,
>         .get_cd = mmc_gpio_get_cd,
> +       .enable_sdio_irq = msdc_enable_sdio_irq,
> +       .ack_sdio_irq = msdc_ack_sdio_irq,
>         .start_signal_voltage_switch = msdc_ops_switch_volt,
>         .card_busy = msdc_card_busy,
>         .execute_tuning = msdc_execute_tuning,
> @@ -2147,6 +2187,9 @@ static int msdc_drv_probe(struct platform_device *pdev)
>         else
>                 mmc->f_min = DIV_ROUND_UP(host->src_clk_freq, 4 * 4095);
>
> +       if (mmc->caps & MMC_CAP_SDIO_IRQ)
> +               mmc->caps2 |= MMC_CAP2_SDIO_IRQ_NOTHREAD;
> +
>         mmc->caps |= MMC_CAP_ERASE | MMC_CAP_CMD23;
>         /* MMC core transfer sizes tunable parameters */
>         mmc->max_segs = MAX_BD_NUM;
> --
> 1.9.1
>

Kind regards
Uffe