[PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Shaik Sajida Bhanu]

The existing suspend/resume callbacks of sdhci-msm driver are just
gating/un-gating the clocks. During suspend cycle more can be done
like disabling controller, disabling card detection, enabling wake-up events.

So updating the system pm callbacks for performing these extra
actions besides controlling the clocks.

Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
---
Changes since V3:
    Invoking sdhci & cqhci resume if sdhci_host_suspend fails.
    Removed condition check before invoking cqhci_resume since its a dummy function.

Changes since V2:
    Removed disabling/enabling pwr-irq from system pm ops.

Changes since V1:
    Invoking pm_runtime_force_suspend/resume instead of
    sdhci_msm_runtime_suepend/resume.
---
 drivers/mmc/host/sdhci-msm.c | 47 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 45 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 3955fa5d..3559b50 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -2159,9 +2159,52 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
 	return 0;
 }
 
+static int sdhci_msm_suspend(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	int ret;
+
+	if (host->mmc->caps2 & MMC_CAP2_CQE) {
+		ret = cqhci_suspend(host->mmc);
+		if (ret)
+			return ret;
+	}
+
+	ret = sdhci_suspend_host(host);
+	if (ret)
+		goto resume_cqhci;
+
+	ret = pm_runtime_force_suspend(dev);
+	if (!ret)
+		return ret;
+
+	sdhci_resume_host(host);
+
+resume_cqhci:
+	cqhci_resume(host->mmc);
+	return ret;
+}
+
+static int sdhci_msm_resume(struct device *dev)
+{
+	struct sdhci_host *host = dev_get_drvdata(dev);
+	int ret;
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret)
+		return ret;
+
+	ret = sdhci_resume_host(host);
+	if (ret < 0)
+		return ret;
+
+	ret = cqhci_resume(host->mmc);
+	return ret;
+}
+
 static const struct dev_pm_ops sdhci_msm_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
-				pm_runtime_force_resume)
+	SET_SYSTEM_SLEEP_PM_OPS(sdhci_msm_suspend,
+				sdhci_msm_resume)
 	SET_RUNTIME_PM_OPS(sdhci_msm_runtime_suspend,
 			   sdhci_msm_runtime_resume,
 			   NULL)
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member 
of Code Aurora Forum, hosted by The Linux Foundation

Re: [PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Veerabhadrarao Badiganti]

Hi Sajida,

On 2/20/2020 12:15 PM, Shaik Sajida Bhanu wrote:

> The existing suspend/resume callbacks of sdhci-msm driver are just
> gating/un-gating the clocks. During suspend cycle more can be done
> like disabling controller, disabling card detection, enabling wake-up events.
>
> So updating the system pm callbacks for performing these extra
> actions besides controlling the clocks.
>
> Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> ---
> Changes since V3:
>      Invoking sdhci & cqhci resume if sdhci_host_suspend fails.
>      Removed condition check before invoking cqhci_resume since its a dummy function.
>
> Changes since V2:
>      Removed disabling/enabling pwr-irq from system pm ops.
>
> Changes since V1:
>      Invoking pm_runtime_force_suspend/resume instead of
>      sdhci_msm_runtime_suepend/resume.
> ---
>   drivers/mmc/host/sdhci-msm.c | 47 ++++++++++++++++++++++++++++++++++++++++++--
>   1 file changed, 45 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 3955fa5d..3559b50 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -2159,9 +2159,52 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
>   	return 0;
>   }
>   
> +static int sdhci_msm_suspend(struct device *dev)
> +{
> +	struct sdhci_host *host = dev_get_drvdata(dev);
> +	int ret;
> +
> +	if (host->mmc->caps2 & MMC_CAP2_CQE) {
> +		ret = cqhci_suspend(host->mmc);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = sdhci_suspend_host(host);
> +	if (ret)
> +		goto resume_cqhci;
> +
> +	ret = pm_runtime_force_suspend(dev);
> +	if (!ret)
> +		return ret;
> +
> +	sdhci_resume_host(host);
> +
> +resume_cqhci:
> +	cqhci_resume(host->mmc);
> +	return ret;
> +}
> +
> +static int sdhci_msm_resume(struct device *dev)
> +{
> +	struct sdhci_host *host = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = pm_runtime_force_resume(dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = sdhci_resume_host(host);

I'm observing an issue with this change.

After this step, i find interrupt enable register is zero (even though 
it's getting set in sdhci_resume_host()) and

resulting in request timeout for very first command in resume path.

Until its root caused, please hold back this change.

> +	if (ret < 0)
> +		return ret;
> +
> +	ret = cqhci_resume(host->mmc);
> +	return ret;
> +}
> +
>   static const struct dev_pm_ops sdhci_msm_pm_ops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> -				pm_runtime_force_resume)
> +	SET_SYSTEM_SLEEP_PM_OPS(sdhci_msm_suspend,
> +				sdhci_msm_resume)
>   	SET_RUNTIME_PM_OPS(sdhci_msm_runtime_suspend,
>   			   sdhci_msm_runtime_resume,
>   			   NULL)

Re: [PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Ulf Hansson]

On Thu, 20 Feb 2020 at 07:45, Shaik Sajida Bhanu <sbhanu@codeaurora.org> wrote:
>
> The existing suspend/resume callbacks of sdhci-msm driver are just
> gating/un-gating the clocks. During suspend cycle more can be done
> like disabling controller, disabling card detection, enabling wake-up events.
>
> So updating the system pm callbacks for performing these extra
> actions besides controlling the clocks.
>
> Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> ---
> Changes since V3:
>     Invoking sdhci & cqhci resume if sdhci_host_suspend fails.
>     Removed condition check before invoking cqhci_resume since its a dummy function.
>
> Changes since V2:
>     Removed disabling/enabling pwr-irq from system pm ops.
>
> Changes since V1:
>     Invoking pm_runtime_force_suspend/resume instead of
>     sdhci_msm_runtime_suepend/resume.
> ---
>  drivers/mmc/host/sdhci-msm.c | 47 ++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 45 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 3955fa5d..3559b50 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -2159,9 +2159,52 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
>         return 0;
>  }
>
> +static int sdhci_msm_suspend(struct device *dev)
> +{
> +       struct sdhci_host *host = dev_get_drvdata(dev);
> +       int ret;
> +
> +       if (host->mmc->caps2 & MMC_CAP2_CQE) {
> +               ret = cqhci_suspend(host->mmc);
> +               if (ret)
> +                       return ret;
> +       }
> +
> +       ret = sdhci_suspend_host(host);
> +       if (ret)
> +               goto resume_cqhci;

sdhci_suspend_host() can't be called on a device that has been runtime
suspended, as that would lead to accessing device registers when
clocks/PM domains are gated.

Depending on how the corresponding cqhci device is managed from a
runtime PM point of view, it could also be problematic to call
cqhci_suspend().

> +
> +       ret = pm_runtime_force_suspend(dev);

It looks to me that perhaps you could make use of solely
pm_runtime_force_suspend(), then just skip calling
sdhci_suspend|resume_host() altogether. Do you think that could work?

And vice versa for sdhci_msm_resume(), of course.

> +       if (!ret)
> +               return ret;
> +
> +       sdhci_resume_host(host);
> +
> +resume_cqhci:
> +       cqhci_resume(host->mmc);
> +       return ret;
> +}
> +
> +static int sdhci_msm_resume(struct device *dev)
> +{
> +       struct sdhci_host *host = dev_get_drvdata(dev);
> +       int ret;
> +
> +       ret = pm_runtime_force_resume(dev);
> +       if (ret)
> +               return ret;
> +
> +       ret = sdhci_resume_host(host);
> +       if (ret < 0)
> +               return ret;
> +
> +       ret = cqhci_resume(host->mmc);
> +       return ret;
> +}
> +
>  static const struct dev_pm_ops sdhci_msm_pm_ops = {
> -       SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> -                               pm_runtime_force_resume)
> +       SET_SYSTEM_SLEEP_PM_OPS(sdhci_msm_suspend,
> +                               sdhci_msm_resume)
>         SET_RUNTIME_PM_OPS(sdhci_msm_runtime_suspend,
>                            sdhci_msm_runtime_resume,
>                            NULL)
> --
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>

Kind regards
Uffe

Re: [PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Veerabhadrarao Badiganti]

On 3/4/2020 10:16 PM, Stephen Boyd wrote:
> Quoting Ulf Hansson (2020-03-04 07:34:29)
>> On Thu, 20 Feb 2020 at 07:45, Shaik Sajida Bhanu <sbhanu@codeaurora.org> wrote:
>>> The existing suspend/resume callbacks of sdhci-msm driver are just
>>> gating/un-gating the clocks. During suspend cycle more can be done
>>> like disabling controller, disabling card detection, enabling wake-up events.
>>>
>>> So updating the system pm callbacks for performing these extra
>>> actions besides controlling the clocks.
>>>
>>> Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
>>> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
>>> ---
>>> Changes since V3:
>>>      Invoking sdhci & cqhci resume if sdhci_host_suspend fails.
>>>      Removed condition check before invoking cqhci_resume since its a dummy function.
>>>
>>> Changes since V2:
>>>      Removed disabling/enabling pwr-irq from system pm ops.
>>>
>>> Changes since V1:
>>>      Invoking pm_runtime_force_suspend/resume instead of
>>>      sdhci_msm_runtime_suepend/resume.
>>> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
>>> index 3955fa5d..3559b50 100644
>>> --- a/drivers/mmc/host/sdhci-msm.c
>>> +++ b/drivers/mmc/host/sdhci-msm.c
>>> @@ -2159,9 +2159,52 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
> [...]
>>> +
>>> +       ret = sdhci_suspend_host(host);
>>> +       if (ret)
>>> +               goto resume_cqhci;
>> sdhci_suspend_host() can't be called on a device that has been runtime
>> suspended, as that would lead to accessing device registers when
>> clocks/PM domains are gated.
>>
>> Depending on how the corresponding cqhci device is managed from a
>> runtime PM point of view, it could also be problematic to call
>> cqhci_suspend().
> There seems to be another patch floating around here[1] that is an
> attempt at a fix to this patch. They should probably be combined so that
> it's not confusing what's going on.

The other fix is altogether different. It is the fix for the issue seen 
with run-time pm.

whereas this change is for system pm.

>>> +
>>> +       ret = pm_runtime_force_suspend(dev);
>> It looks to me that perhaps you could make use of solely
>> pm_runtime_force_suspend(), then just skip calling
>> sdhci_suspend|resume_host() altogether. Do you think that could work?
> Does that do all the things the commit text mentions is desired for
> system suspend?
>
>>> like disabling controller, disabling card detection, enabling wake-up events.
> [1] https://lore.kernel.org/linux-arm-msm/1583322863-21790-1-git-send-email-vbadigan@codeaurora.org/

Re: [PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Ulf Hansson]

On Wed, 4 Mar 2020 at 17:46, Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Ulf Hansson (2020-03-04 07:34:29)
> > On Thu, 20 Feb 2020 at 07:45, Shaik Sajida Bhanu <sbhanu@codeaurora.org> wrote:
> > >
> > > The existing suspend/resume callbacks of sdhci-msm driver are just
> > > gating/un-gating the clocks. During suspend cycle more can be done
> > > like disabling controller, disabling card detection, enabling wake-up events.
> > >
> > > So updating the system pm callbacks for performing these extra
> > > actions besides controlling the clocks.
> > >
> > > Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
> > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > ---
> > > Changes since V3:
> > >     Invoking sdhci & cqhci resume if sdhci_host_suspend fails.
> > >     Removed condition check before invoking cqhci_resume since its a dummy function.
> > >
> > > Changes since V2:
> > >     Removed disabling/enabling pwr-irq from system pm ops.
> > >
> > > Changes since V1:
> > >     Invoking pm_runtime_force_suspend/resume instead of
> > >     sdhci_msm_runtime_suepend/resume.
> > > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> > > index 3955fa5d..3559b50 100644
> > > --- a/drivers/mmc/host/sdhci-msm.c
> > > +++ b/drivers/mmc/host/sdhci-msm.c
> > > @@ -2159,9 +2159,52 @@ static __maybe_unused int sdhci_msm_runtime_resume(struct device *dev)
> [...]
> > > +
> > > +       ret = sdhci_suspend_host(host);
> > > +       if (ret)
> > > +               goto resume_cqhci;
> >
> > sdhci_suspend_host() can't be called on a device that has been runtime
> > suspended, as that would lead to accessing device registers when
> > clocks/PM domains are gated.
> >
> > Depending on how the corresponding cqhci device is managed from a
> > runtime PM point of view, it could also be problematic to call
> > cqhci_suspend().
>
> There seems to be another patch floating around here[1] that is an
> attempt at a fix to this patch. They should probably be combined so that
> it's not confusing what's going on.

Yeah, it would be easier if these are discussed together.

>
> >
> > > +
> > > +       ret = pm_runtime_force_suspend(dev);
> >
> > It looks to me that perhaps you could make use of solely
> > pm_runtime_force_suspend(), then just skip calling
> > sdhci_suspend|resume_host() altogether. Do you think that could work?
>
> Does that do all the things the commit text mentions is desired for
> system suspend?

No. :-)

But why is system wakeup needed for an eMMC card?

>
> > > like disabling controller, disabling card detection, enabling wake-up events.
>
> [1] https://lore.kernel.org/linux-arm-msm/1583322863-21790-1-git-send-email-vbadigan@codeaurora.org/

Kind regards
Uffe

Re: [PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Ulf Hansson]

On Thu, 19 Mar 2020 at 18:42, Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Ulf Hansson (2020-03-06 02:07:41)
> > On Wed, 4 Mar 2020 at 17:46, Stephen Boyd <swboyd@chromium.org> wrote:
> > >
> > > Quoting Ulf Hansson (2020-03-04 07:34:29)
> > > > On Thu, 20 Feb 2020 at 07:45, Shaik Sajida Bhanu <sbhanu@codeaurora.org> wrote:
> > > > >
> > > > > The existing suspend/resume callbacks of sdhci-msm driver are just
> > > > > gating/un-gating the clocks. During suspend cycle more can be done
> > > > > like disabling controller, disabling card detection, enabling wake-up events.
> > > > >
> > > > > So updating the system pm callbacks for performing these extra
> > > > > actions besides controlling the clocks.
> > > > >
> > > > > Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
> > > > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > > > ---
> [...]
> >
> > >
> > > >
> > > > > +
> > > > > +       ret = pm_runtime_force_suspend(dev);
> > > >
> > > > It looks to me that perhaps you could make use of solely
> > > > pm_runtime_force_suspend(), then just skip calling
> > > > sdhci_suspend|resume_host() altogether. Do you think that could work?
> > >
> > > Does that do all the things the commit text mentions is desired for
> > > system suspend?
> >
> > No. :-)
> >
> > But why is system wakeup needed for an eMMC card?
> >
>
> I don't know if system wakeup is needed for an eMMC card. Probably only
> if you plug in a card and some daemon wants to wake up and probe the
> card for auto-play or something like that? Seems possible so might as
> well expose the CD gpio as a wakeup in that case and let userspace
> decide if it wants to do that.

Right, card detect IRQs could be useful for system wakeups.

I assume you are using a GPIO IRQ for that, which is easily managed,
as the runtime PM status of the mmc controller is irrelevant when
configuring the GPIO IRQ as wakeup.

We even have a helper for doing this, mmc_gpio_set_cd_wake().

>
> Is runtime suspended state the same as system suspended state here
> though? The commit text seems to imply that only clks are disabled when
> it's desirable to disable the entire controller. I'm still fuzzy on how
> runtime PM and system PM interact because it seems to have changed since
> I looked last a few years ago. If the driver can stay in a runtime
> suspended state across system suspend then I'm all for it. That would
> save time for system PM transitions.

In most cases this should be possible. And so far, for this case, I
haven't found a good reason to why it shouldn't work.

Although, perhaps we need to improve some of the sdhci's library
functions for PM, to better support this.

Kind regards
Uffe

Re: [PATCH V4] mmc: sdhci-msm: Update system suspend/resume callbacks of sdhci-msm platform driver

[Ulf Hansson]

On Wed, 15 Apr 2020 at 01:16, Stephen Boyd <swboyd@chromium.org> wrote:
>
> Quoting Ulf Hansson (2020-03-20 03:22:01)
> > On Thu, 19 Mar 2020 at 18:42, Stephen Boyd <swboyd@chromium.org> wrote:
> > >
> > > Quoting Ulf Hansson (2020-03-06 02:07:41)
> > > > On Wed, 4 Mar 2020 at 17:46, Stephen Boyd <swboyd@chromium.org> wrote:
> > > > >
> > > > > Quoting Ulf Hansson (2020-03-04 07:34:29)
> > > > > > On Thu, 20 Feb 2020 at 07:45, Shaik Sajida Bhanu <sbhanu@codeaurora.org> wrote:
> > > > > > >
> > > > > > > The existing suspend/resume callbacks of sdhci-msm driver are just
> > > > > > > gating/un-gating the clocks. During suspend cycle more can be done
> > > > > > > like disabling controller, disabling card detection, enabling wake-up events.
> > > > > > >
> > > > > > > So updating the system pm callbacks for performing these extra
> > > > > > > actions besides controlling the clocks.
> > > > > > >
> > > > > > > Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
> > > > > > > Reviewed-by: Stephen Boyd <swboyd@chromium.org>
> > > > > > > ---
> > > [...]
> > > >
> > > > >
> > > > > >
> > > > > > > +
> > > > > > > +       ret = pm_runtime_force_suspend(dev);
> > > > > >
> > > > > > It looks to me that perhaps you could make use of solely
> > > > > > pm_runtime_force_suspend(), then just skip calling
> > > > > > sdhci_suspend|resume_host() altogether. Do you think that could work?
> > > > >
> > > > > Does that do all the things the commit text mentions is desired for
> > > > > system suspend?
> > > >
> > > > No. :-)
> > > >
> > > > But why is system wakeup needed for an eMMC card?
> > > >
> > >
> > > I don't know if system wakeup is needed for an eMMC card. Probably only
> > > if you plug in a card and some daemon wants to wake up and probe the
> > > card for auto-play or something like that? Seems possible so might as
> > > well expose the CD gpio as a wakeup in that case and let userspace
> > > decide if it wants to do that.
> >
> > Right, card detect IRQs could be useful for system wakeups.
> >
> > I assume you are using a GPIO IRQ for that, which is easily managed,
> > as the runtime PM status of the mmc controller is irrelevant when
> > configuring the GPIO IRQ as wakeup.
> >
> > We even have a helper for doing this, mmc_gpio_set_cd_wake().
>
> Right. Maybe mmc_gpio_set_cd_wake() needs to be called from somewhere in
> the sdhci core?

Yes, that seems reasonable.

>
> >
> > >
> > > Is runtime suspended state the same as system suspended state here
> > > though? The commit text seems to imply that only clks are disabled when
> > > it's desirable to disable the entire controller. I'm still fuzzy on how
> > > runtime PM and system PM interact because it seems to have changed since
> > > I looked last a few years ago. If the driver can stay in a runtime
> > > suspended state across system suspend then I'm all for it. That would
> > > save time for system PM transitions.
> >
> > In most cases this should be possible. And so far, for this case, I
> > haven't found a good reason to why it shouldn't work.
> >
> > Although, perhaps we need to improve some of the sdhci's library
> > functions for PM, to better support this.
> >
>
> So does that mean it's all just working then? Nothing to do here except
> make wakeup irqs for CD work?

Well, if it "works " or not, I am not really sure.

My point is, I think most of the things that need to be managed at
system suspend/resume are the same things that need to be managed
during runtime suspend/resume (except wakeups). So, rather than
implementing a whole bunch of system suspend/resume specific things,
why not make use of the runtime suspend/resume callbacks instead.

Kind regards
Uffe