Re: [PATCH v9 3/3] mmc: mediatek: add support for SDIO eint wakup IRQ

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

On Mon, 2022-04-04 at 17:01 +0200, Ulf Hansson wrote:
> On Tue, 29 Mar 2022 at 05:29, 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 "state_eint" is mandatory. Since
> > this feature depends on asynchronous interrupts, "wakeup-source",
> > "keep-power-in-suspend" and "cap-sdio-irq" flags are necessary, and
> > the interrupts list should be extended:
> >         &mmcX {
> >                 ...
> >                 interrupts-extended = <...>,
> >                                       <&pio xxx
> > IRQ_TYPE_LEVEL_LOW>;
> >                 ...
> >                 pinctrl-names = "default", "state_uhs",
> > "state_eint";
> >                 ...
> >                 pinctrl-2 = <&mmc2_pins_eint>;
> >                 ...
> >                 cap-sdio-irq;
> >                 keep-power-in-suspend;
> >                 wakeup-source;
> >                 ...
> >         };
> > 
> > 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 | 94
> > +++++++++++++++++++++++++++++++++++----
> >  1 file changed, 86 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > index 65037e1d7723..2905d7134243 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>
> >   */
> > 
> > @@ -20,6 +20,7 @@
> >  #include <linux/platform_device.h>
> >  #include <linux/pm.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/pm_wakeirq.h>
> >  #include <linux/regulator/consumer.h>
> >  #include <linux/slab.h>
> >  #include <linux/spinlock.h>
> > @@ -440,8 +441,11 @@ struct msdc_host {
> >         struct pinctrl *pinctrl;
> >         struct pinctrl_state *pins_default;
> >         struct pinctrl_state *pins_uhs;
> > +       struct pinctrl_state *pins_eint;
> >         struct delayed_work req_timeout;
> >         int irq;                /* host interrupt */
> > +       int eint_irq;           /* interrupt from sdio device for
> > waking up system */
> > +       int sdio_wake_irq_depth;
> >         struct reset_control *reset;
> > 
> >         struct clk *src_clk;    /* msdc source clock */
> > @@ -465,6 +469,7 @@ 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 +1532,12 @@ 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_enable_async_irq(mmc->card)) {
> 
> It might not be obvious, but in fact mmc->card always exists in this
> case, hence there is no need to check the pointer before using it.

this check is removed in v10.

> 
> > +               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)
> > @@ -2631,6 +2638,18 @@ static int msdc_drv_probe(struct
> > platform_device *pdev)
> >                 goto host_free;
> >         }
> > 
> > +       /* Support for SDIO eint irq ? */
> > +       if (mmc->pm_caps & MMC_PM_WAKE_SDIO_IRQ) {
> > +               host->pins_eint = pinctrl_lookup_state(host-
> > >pinctrl, "state_eint");
> > +               if (IS_ERR(host->pins_eint)) {
> > +                       ret = dev_err_probe(&pdev->dev,
> > PTR_ERR(host->pins_eint),
> > +                                           "Cannot find pinctrl
> > eint!\n");
> > +                       goto host_free;
> > +               }
> > +
> > +               host->sdio_eint_ready = true;
> 
> Rather than using a separate variable, couldn't we just check "if
> (host->pins_eint)" to know whether wakeup settings shall be managed?

This variable is removed in v10, use host->pins_eint instead. 

> 
> > +       }
> > +
> >         msdc_of_property_parse(pdev, host);
> > 
> >         host->dev = &pdev->dev;
> > @@ -2722,6 +2741,21 @@ static int msdc_drv_probe(struct
> > platform_device *pdev)
> >         if (ret)
> >                 goto release;
> > 
> > +       if (host->sdio_eint_ready) {
> > +               host->eint_irq = irq_of_parse_and_map(host->dev-
> > >of_node, 1);
> > +               ret = host->eint_irq ?
> > dev_pm_set_dedicated_wake_irq(host->dev, host->eint_irq) :
> > +                     -ENODEV;
> 
> I think it would make better sense to call
> dev_pm_set_dedicated_wake_irq() from msdc_enable_sdio_irq(). In this
> way, you can still support SDIO irqs, even if there are no GPIO irq
> for available for re-routing.
> 
> In other words, if the GPIO irq is available, then that's the best
> option and we should use that - otherwise we need to keep preventing
> runtime-suspend by bumping the runtime PM usage count.

dev_pm_set_dedicated_wake_irq() is replaced with
dev_pm_set_dedicated_wake_irq_reverse() to assure msdc irq is disabled
earlier than enable wake irq in rpm_suspend(), and it is moved to
msdc_enable_sdio_irq() phase.

> 
> > +
> > +               if (ret) {
> > +                       dev_err(host->dev, "Failed to register
> > data1 eint irq!\n");
> > +                       goto release;
> > +               }
> > +
> > +               dev_pm_disable_wake_irq(host->dev);
> > +               pinctrl_select_state(host->pinctrl, host-
> > >pins_uhs);
> > +       }
> > +
> > +       device_init_wakeup(host->dev, true);
> 
> I think this better belongs under the condition of whether
> MMC_PM_WAKE_SDIO_IRQ and MMC_PM_KEEP_POWER caps are set.

Both of them are checked before parsing eint pinstate in v10.

> 
> >         pm_runtime_set_active(host->dev);
> >         pm_runtime_set_autosuspend_delay(host->dev,
> > MTK_MMC_AUTOSUSPEND_DELAY);
> >         pm_runtime_use_autosuspend(host->dev);
> > @@ -2734,6 +2768,7 @@ static int msdc_drv_probe(struct
> > platform_device *pdev)
> >         return 0;
> >  end:
> >         pm_runtime_disable(host->dev);
> > +       dev_pm_clear_wake_irq(host->dev);
> >  release:
> >         platform_set_drvdata(pdev, NULL);
> >         msdc_deinit_hw(host);
> > @@ -2845,6 +2880,16 @@ static int __maybe_unused
> > msdc_runtime_suspend(struct device *dev)
> >         struct msdc_host *host = mmc_priv(mmc);
> > 
> >         msdc_save_reg(host);
> > +
> > +       if (host->sdio_eint_ready) {
> 
> The core provides a helper function, sdio_irq_claimed(), that can be
> used to know whether there is an SDIO irq registered. It looks like
> that certainly can be useful here.

Yes. We need sdio_irq_claimed() check since set dedicated wake irq is
been moved to claim irq stage.

> 
> > +               disable_irq(host->irq);
> > +               pinctrl_select_state(host->pinctrl, host-
> > >pins_eint);
> > +               if (host->sdio_wake_irq_depth == 0) {
> > +                       dev_pm_enable_wake_irq(dev);
> 
> This should be managed from the runtime PM core. See rpm_suspend().
> 
> Or perhaps there is a reason that doesn't work for you?
> 
> > +                       host->sdio_wake_irq_depth++;
> 
> Again, sdio_irq_claimed() is probably better to use.
> 
> > +               }
> > +               sdr_clr_bits(host->base + SDC_CFG,
> > SDC_CFG_SDIOIDE);
> > +       }
> >         msdc_gate_clock(host);
> >         return 0;
> >  }
> > @@ -2860,12 +2905,25 @@ static int __maybe_unused
> > msdc_runtime_resume(struct device *dev)
> >                 return ret;
> > 
> >         msdc_restore_reg(host);
> > +
> > +       if (host->sdio_eint_ready) {
> > +               if (host->sdio_wake_irq_depth > 0) {
> > +                       dev_pm_disable_wake_irq(dev);
> > +                       host->sdio_wake_irq_depth--;
> > +                       sdr_set_bits(host->base + SDC_CFG,
> > SDC_CFG_SDIOIDE);
> > +               } else {
> > +                       sdr_clr_bits(host->base + MSDC_INTEN,
> > MSDC_INTEN_SDIOIRQ);
> > +               }
> > +               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);
> > +       struct msdc_host *host = mmc_priv(mmc);
> >         int ret;
> > 
> >         if (mmc->caps2 & MMC_CAP2_CQE) {
> > @@ -2874,16 +2932,36 @@ static int __maybe_unused
> > msdc_suspend(struct device *dev)
> >                         return ret;
> >         }
> > 
> > +       if (host->sdio_eint_ready)
> > +               enable_irq_wake(host->eint_irq);
> 
> The PM core should manage this for us through dpm_suspend_noirq(), I
> think. We just need to make sure that the runtime PM status of the
> device has been set to RPM_SUSPENDED before dpm_suspend_noirq()  gets
> called. Have a look at dpm_suspend_noirq() ->
> device_wakeup_arm_wake_irqs() -> dev_pm_arm_wake_irq().
> 
> In other words (and unless I am missing something), if we continue to
> call pm_runtime_force_suspend() from a ->suspend() callback this
> should work just fine.

This part is simplified in v10. dpm/rpm system can manage wake irq
well.

> 
> > +
> >         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)
> >  {
> > +       struct mmc_host *mmc = dev_get_drvdata(dev);
> > +       struct msdc_host *host = mmc_priv(mmc);
> > +
> > +       if (host->sdio_eint_ready) {
> > +               disable_irq_wake(host->eint_irq);
> > +
> > +               /*
> > +                * In noirq resume stage, msdc_runtime_resume()
> > +                * won't be called, so disalbe wake irq here
> > +                * to block dedicated wake irq handler callback.
> > +                */
> > +               if (likely(host->sdio_wake_irq_depth > 0)) {
> > +                       dev_pm_disable_wake_irq(dev);
> > +                       host->sdio_wake_irq_depth--;
> > +               }
> 
> Similar comment as from the system suspend case. I don't think we
> need
> to move to the noirq phase.
> 
> Or maybe I am missing something here?

They are restored to system suspend stage in V10.
But I have to use rpm_suspend()/rpm_resueme() instead of 
pm_runtime_force_suspend()/pm_runtime_force_resmue(). 
pm_runtime_force_resume() will go out directly because rpm state is
RPM_SUSPENDED in system resume stage.

> 
> > +       }
> > +
> >         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)
> >  };
> > 
> > --
> > 2.25.1
> > 
> 

Regards,
Axe