linux-kernel - Re: [PATCH 1/2] mmc: mediatek: fix SDIO IRQ interrupt handle flow

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Message-ID: <CAPDyKFrXU4bpKeB7Aa15j2nHqUCn-bk+YKn9_vkznmi+PS8H7A@mail.gmail.com>
Date:   Fri, 14 Jun 2019 11:46:52 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Jjian Zhou <jjian.zhou@...iatek.com>
Cc:     Chaotian Jing <chaotian.jing@...iatek.com>,
        Matthias Brugger <matthias.bgg@...il.com>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        linux-mediatek@...ts.infradead.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Yong Mao <yong.mao@...iatek.com>,
        srv_heupstream <srv_heupstream@...iatek.com>
Subject: Re: [PATCH 1/2] mmc: mediatek: fix SDIO IRQ interrupt handle flow

On Fri, 14 Jun 2019 at 07:26, Jjian Zhou <jjian.zhou@...iatek.com> wrote:
>
> From: jjian zhou <jjian.zhou@...iatek.com>
>
> SDIO IRQ is triggered by low level. It need disable SDIO IRQ
> detected function. Otherwise the interrupt register can't be cleared.
> It will process the interrupt more.
>
> Signed-off-by: Jjian Zhou <jjian.zhou@...iatek.com>
> Signed-off-by: Chaotian Jing <chaotian.jing@...iatek.com>
> Signed-off-by: Yong Mao <yong.mao@...iatek.com>
> ---
>  drivers/mmc/host/mtk-sd.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> index c518cc2..29992ae 100644
> --- a/drivers/mmc/host/mtk-sd.c
> +++ b/drivers/mmc/host/mtk-sd.c
> @@ -1389,10 +1389,12 @@ static void __msdc_enable_sdio_irq(struct mmc_host *mmc, int enb)
>         struct msdc_host *host = mmc_priv(mmc);
>
>         spin_lock_irqsave(&host->lock, flags);
> -       if (enb)
> +       if (enb) {
>                 sdr_set_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);
> -       else
> +               sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);
> +       } else {
>                 sdr_clr_bits(host->base + MSDC_INTEN, MSDC_INTEN_SDIOIRQ);

Rather than clearing SDC_CFG_SDIOIDE in the irq handler, you need to
do it here. As otherwise when the mmc core calls
host->ops->enable_sdio_irq() to disable the SDIO IRQ, it may stay
enabled.

> +       }
>         spin_unlock_irqrestore(&host->lock, flags);
>  }
>
> @@ -1422,6 +1424,8 @@ static irqreturn_t msdc_irq(int irq, void *dev_id)
>                 spin_lock_irqsave(&host->lock, flags);
>                 events = readl(host->base + MSDC_INT);
>                 event_mask = readl(host->base + MSDC_INTEN);
> +               if ((events & event_mask) & MSDC_INT_SDIOIRQ)
> +                       sdr_clr_bits(host->base + SDC_CFG, SDC_CFG_SDIOIDE);

As stated above, I suggest you move this into __msdc_enable_sdio_irq()
and thus call that function from here instead. Well, that doesn't work
as is, because of the spin lock, so you rather need to make a
sub-function of __msdc_enable_sdio_irq, that don't take/releases the
lock.

I hope that was clear. If not, I can post a patch to show you what I mean.


>                 /* clear interrupts */
>                 writel(events & event_mask, host->base + MSDC_INT);
>
> @@ -1572,10 +1576,7 @@ static void msdc_init_hw(struct msdc_host *host)
>         sdr_set_bits(host->base + SDC_CFG, SDC_CFG_SDIO);
>
>         /* 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);
> +       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);
> --
> 1.9.1
>

Kind regards
Uffe