Re: [PATCH v5 3/3] mmc: mediatek: add support for SDIO eint IRQ

[Axe Yang <axe.yang@mediatek.com>]

On Mon, 2022-02-14 at 16:54 +0100, Ulf Hansson wrote:
> On Fri, 21 Jan 2022 at 08:19, Axe Yang <axe.yang@mediatek.com> wrote:
> > 
> > Add support for eint IRQ when MSDC is used as an SDIO host. This
> > feature requires SDIO device support async IRQ function. With this
> > feature, SDIO host can be awakened by SDIO card in suspend state,
> > without additional pin.
> > 
> > MSDC driver will time-share the SDIO DAT1 pin. During suspend, MSDC
> > turn off clock and switch SDIO DAT1 pin to GPIO mode. And during
> > resume, switch GPIO function back to DAT1 mode then turn on clock.
> > 
> > Some device tree property should be added or modified in MSDC node
> > to support SDIO eint IRQ. Pinctrls named state_dat1 and state_eint
> > are mandatory. And cap-sdio-async-irq flag is necessary since this
> > feature depends on asynchronous interrupt:
> >         &mmcX {
> >                 ...
> >                 pinctrl-names = "default", "state_uhs",
> > "state_eint",
> >                                 "state_dat1";
> 
> Looks like you need to update the DT docs too to describe these new
> things, right?
Will update the docs in next patchset.

> 
> >                 ...
> >                 pinctrl-2 = <&mmc2_pins_eint>;
> >                 pinctrl-3 = <&mmc2_pins_dat1>;
> >                 ...
> >                 cap-sdio-async-irq;
> >                 ...
> >         };
> > 
> > Co-developed-by: Yong Mao <yong.mao@mediatek.com>
> > Signed-off-by: Yong Mao <yong.mao@mediatek.com>
> > Signed-off-by: Axe Yang <axe.yang@mediatek.com>
> > ---
> >  drivers/mmc/host/mtk-sd.c | 123
> > +++++++++++++++++++++++++++++++++++---
> >  1 file changed, 115 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > index 65037e1d7723..f8e38228d810 100644
> > --- a/drivers/mmc/host/mtk-sd.c
> > +++ b/drivers/mmc/host/mtk-sd.c
> > @@ -1,6 +1,6 @@
> >  // SPDX-License-Identifier: GPL-2.0-only
> >  /*
> > - * Copyright (c) 2014-2015 MediaTek Inc.
> > + * Copyright (c) 2014-2015, 2022 MediaTek Inc.
> >   * Author: Chaotian.Jing <chaotian.jing@mediatek.com>
> >   */
> > 
> > @@ -9,6 +9,7 @@
> >  #include <linux/clk.h>
> >  #include <linux/delay.h>
> >  #include <linux/dma-mapping.h>
> > +#include <linux/gpio/consumer.h>
> >  #include <linux/iopoll.h>
> >  #include <linux/ioport.h>
> >  #include <linux/irq.h>
> > @@ -440,8 +441,12 @@ struct msdc_host {
> >         struct pinctrl *pinctrl;
> >         struct pinctrl_state *pins_default;
> >         struct pinctrl_state *pins_uhs;
> > +       struct pinctrl_state *pins_eint;
> > +       struct pinctrl_state *pins_dat1;
> >         struct delayed_work req_timeout;
> >         int irq;                /* host interrupt */
> > +       int eint_irq;           /* device interrupt */
> > +       int sdio_irq_cnt;       /* irq enable cnt */
> >         struct reset_control *reset;
> > 
> >         struct clk *src_clk;    /* msdc source clock */
> > @@ -465,6 +470,7 @@ struct msdc_host {
> >         bool hs400_tuning;      /* hs400 mode online tuning */
> >         bool internal_cd;       /* Use internal card-detect logic
> > */
> >         bool cqhci;             /* support eMMC hw cmdq */
> > +       bool sdio_eint_ready;   /* Ready to support SDIO eint
> > interrupt */
> >         struct msdc_save_para save_para; /* used when gate HCLK */
> >         struct msdc_tune_para def_tune_para; /* default tune
> > setting */
> >         struct msdc_tune_para saved_tune_para; /* tune result of
> > CMD21/CMD19 */
> > @@ -1527,10 +1533,12 @@ static void msdc_enable_sdio_irq(struct
> > mmc_host *mmc, int enb)
> >         __msdc_enable_sdio_irq(host, enb);
> >         spin_unlock_irqrestore(&host->lock, flags);
> > 
> > -       if (enb)
> > -               pm_runtime_get_noresume(host->dev);
> > -       else
> > -               pm_runtime_put_noidle(host->dev);
> > +       if (mmc->card && !mmc->card->cccr.enable_async_irq) {
> > +               if (enb)
> > +                       pm_runtime_get_noresume(host->dev);
> > +               else
> > +                       pm_runtime_put_noidle(host->dev);
> > +       }
> >  }
> > 
> >  static irqreturn_t msdc_cmdq_irq(struct msdc_host *host, u32
> > intsts)
> > @@ -2461,6 +2469,48 @@ static const struct mmc_host_ops mt_msdc_ops
> > = {
> >         .hw_reset = msdc_hw_reset,
> >  };
> > 
> > +static irqreturn_t msdc_sdio_eint_irq(int irq, void *dev_id)
> > +{
> > +       struct msdc_host *host = dev_id;
> > +       struct mmc_host *mmc = mmc_from_priv(host);
> > +
> > +       spin_lock(&host->lock);
> > +       if (likely(host->sdio_irq_cnt > 0)) {
> > +               disable_irq_nosync(host->eint_irq);
> > +               disable_irq_wake(host->eint_irq);
> > +               host->sdio_irq_cnt--;
> > +       }
> > +       spin_unlock(&host->lock);
> > +
> > +       sdio_signal_irq(mmc);
> > +
> > +       return IRQ_HANDLED;
> > +}
> > +
> > +static int msdc_request_dat1_eint_irq(struct msdc_host *host)
> > +{
> > +       struct gpio_desc *desc;
> > +       int irq, ret;
> > +
> > +       desc = devm_gpiod_get(host->dev, "eint", GPIOD_IN);
> > +       if (IS_ERR(desc))
> > +               return PTR_ERR(desc);
> > +
> > +       irq = gpiod_to_irq(desc);
> > +       if (irq < 0)
> > +               return irq;
> > +
> > +       ret = devm_request_threaded_irq(host->dev, irq, NULL,
> > msdc_sdio_eint_irq,
> > +                                       IRQF_TRIGGER_LOW |
> > IRQF_ONESHOT | IRQF_NO_AUTOEN,
> > +                                       "sdio-eint", host);
> 
> Again, I think you need to update the DT doc to describe these new
> IRQ/GPIO things.
Will update the docs in next patchset.

> 
> > +       if (ret)
> > +               return ret;
> > +
> > +       host->eint_irq = irq;
> > +
> > +       return 0;
> > +}
> > +
> >  static const struct cqhci_host_ops msdc_cmdq_ops = {
> >         .enable         = msdc_cqe_enable,
> >         .disable        = msdc_cqe_disable,
> > @@ -2631,6 +2681,23 @@ static int msdc_drv_probe(struct
> > platform_device *pdev)
> >                 goto host_free;
> >         }
> > 
> > +       if (!(mmc->caps2 & MMC_CAP2_NO_SDIO) && (mmc->caps2 &
> > MMC_CAP2_SDIO_ASYNC_IRQ)) {
> > +               /* Support for SDIO eint irq */
> > +               host->pins_eint = pinctrl_lookup_state(host-
> > >pinctrl, "state_eint");
> > +               if (IS_ERR(host->pins_eint)) {
> > +                       dev_dbg(&pdev->dev, "Cannot find pinctrl
> > eint!\n");
> > +               } else {
> > +                       host->pins_dat1 =
> > pinctrl_lookup_state(host->pinctrl, "state_dat1");
> > +                       if (IS_ERR(host->pins_dat1)) {
> > +                               ret = dev_err_probe(&pdev->dev,
> > PTR_ERR(host->pins_dat1),
> > +                                                   "Cannot find
> > pinctrl dat1!\n");
> > +                               goto host_free;
> > +                       }
> > +
> > +                       host->sdio_eint_ready = true;
> > +               }
> > +       }
> > +
> >         msdc_of_property_parse(pdev, host);
> > 
> >         host->dev = &pdev->dev;
> > @@ -2722,6 +2789,16 @@ static int msdc_drv_probe(struct
> > platform_device *pdev)
> >         if (ret)
> >                 goto release;
> > 
> > +       if (host->sdio_eint_ready) {
> > +               ret = msdc_request_dat1_eint_irq(host);
> > +               if (ret) {
> > +                       dev_err(host->dev, "Failed to register
> > data1 eint irq!\n");
> > +                       goto release;
> > +               }
> > +
> > +               pinctrl_select_state(host->pinctrl, host-
> > >pins_dat1);
> > +       }
> > +
> >         pm_runtime_set_active(host->dev);
> >         pm_runtime_set_autosuspend_delay(host->dev,
> > MTK_MMC_AUTOSUSPEND_DELAY);
> >         pm_runtime_use_autosuspend(host->dev);
> > @@ -2843,8 +2920,22 @@ static int __maybe_unused
> > msdc_runtime_suspend(struct device *dev)
> >  {
> >         struct mmc_host *mmc = dev_get_drvdata(dev);
> >         struct msdc_host *host = mmc_priv(mmc);
> > +       unsigned long flags;
> > 
> >         msdc_save_reg(host);
> > +
> > +       if (host->sdio_eint_ready) {
> > +               disable_irq(host->irq);
> > +               pinctrl_select_state(host->pinctrl, host-
> > >pins_eint);
> > +               spin_lock_irqsave(&host->lock, flags);
> > +               if (host->sdio_irq_cnt == 0) {
> > +                       enable_irq(host->eint_irq);
> > +                       enable_irq_wake(host->eint_irq);
> > +                       host->sdio_irq_cnt++;
> > +               }
> > +               sdr_clr_bits(host->base + SDC_CFG,
> > SDC_CFG_SDIOIDE);
> > +               spin_unlock_irqrestore(&host->lock, flags);
> > +       }
> >         msdc_gate_clock(host);
> >         return 0;
> >  }
> > @@ -2853,6 +2944,7 @@ static int __maybe_unused
> > msdc_runtime_resume(struct device *dev)
> >  {
> >         struct mmc_host *mmc = dev_get_drvdata(dev);
> >         struct msdc_host *host = mmc_priv(mmc);
> > +       unsigned long flags;
> >         int ret;
> > 
> >         ret = msdc_ungate_clock(host);
> > @@ -2860,10 +2952,25 @@ static int __maybe_unused
> > msdc_runtime_resume(struct device *dev)
> >                 return ret;
> > 
> >         msdc_restore_reg(host);
> > +
> > +       if (host->sdio_eint_ready) {
> > +               spin_lock_irqsave(&host->lock, flags);
> > +               if (host->sdio_irq_cnt > 0) {
> > +                       disable_irq_nosync(host->eint_irq);
> > +                       disable_irq_wake(host->eint_irq);
> > +                       host->sdio_irq_cnt--;
> > +                       sdr_set_bits(host->base + SDC_CFG,
> > SDC_CFG_SDIOIDE);
> > +               } else {
> > +                       sdr_clr_bits(host->base + MSDC_INTEN,
> > MSDC_INTEN_SDIOIRQ);
> > +               }
> > +               spin_unlock_irqrestore(&host->lock, flags);
> > +               pinctrl_select_state(host->pinctrl, host-
> > >pins_uhs);
> > +               enable_irq(host->irq);
> > +       }
> >         return 0;
> >  }
> > 
> > -static int __maybe_unused msdc_suspend(struct device *dev)
> > +static int __maybe_unused msdc_suspend_noirq(struct device *dev)
> >  {
> >         struct mmc_host *mmc = dev_get_drvdata(dev);
> >         int ret;
> > @@ -2877,13 +2984,13 @@ static int __maybe_unused
> > msdc_suspend(struct device *dev)
> >         return pm_runtime_force_suspend(dev);
> >  }
> > 
> > -static int __maybe_unused msdc_resume(struct device *dev)
> > +static int __maybe_unused msdc_resume_noirq(struct device *dev)
> >  {
> >         return pm_runtime_force_resume(dev);
> >  }
> > 
> >  static const struct dev_pm_ops msdc_dev_pm_ops = {
> > -       SET_SYSTEM_SLEEP_PM_OPS(msdc_suspend, msdc_resume)
> > +       SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(msdc_suspend_noirq,
> > msdc_resume_noirq)
> >         SET_RUNTIME_PM_OPS(msdc_runtime_suspend,
> > msdc_runtime_resume, NULL)
> >  };
> > 
> 
> Overall the approach makes perfect sense to me!
> 
> However, I think the code can be simplified and made more robust by
> using the wakeirq interface instead. Please have a look at
> dev_pm_set_dedicated_wake_irq() and friends. Using them, will let the
> runtime PM core deal with disabling/enabling the IRQ, rather than
> having to do that manually by the driver, for example.
> 
> If you want to get inspired by an existing implementation, please
> have
> a look at the sdhci-omap driver.
Will read the wakeirq interfaces and use them in next version. Thanks
for review.

Regards,
Axe Yang