| Message ID | 20230808202319.191434-1-limings@nvidia.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v7] mmc: sdhci-of-dwcmshc: Add runtime PM operations | expand |
On Fri, 11 Aug 2023 at 07:57, Adrian Hunter <adrian.hunter@intel.com> wrote: > > On 10/08/23 19:34, Ulf Hansson wrote: > > On Thu, 10 Aug 2023 at 14:44, Adrian Hunter <adrian.hunter@intel.com> wrote: > >> > >> On 10/08/23 13:21, Ulf Hansson wrote: > >>> On Thu, 10 Aug 2023 at 10:13, Adrian Hunter <adrian.hunter@intel.com> wrote: > >>>> > >>>> On 8/08/23 23:23, Liming Sun wrote: > >>>>> This commit implements the runtime PM operations to disable eMMC > >>>>> card clock when idle. > >>>>> > >>>>> Reviewed-by: David Thompson <davthompson@nvidia.com> > >>>>> Signed-off-by: Liming Sun <limings@nvidia.com> > >>>>> --- > >>>>> v6->v7: > >>>>> - Address Ulf's comment; > >>>>> v5->v6: > >>>>> - Address Adrian's more comments and add coordination between > >>>>> runtime PM and system PM; > >>>>> v4->v5: > >>>>> - Address Adrian's comment to move the pm_enable to the end to > >>>>> avoid race; > >>>>> v3->v4: > >>>>> - Fix compiling reported by 'kernel test robot'; > >>>>> v2->v3: > >>>>> - Revise the commit message; > >>>>> v1->v2: > >>>>> Updates for comments from Ulf: > >>>>> - Make the runtime PM logic generic for sdhci-of-dwcmshc; > >>>>> v1: Initial version. > >>>>> --- > >>>>> drivers/mmc/host/sdhci-of-dwcmshc.c | 72 ++++++++++++++++++++++++++++- > >>>>> 1 file changed, 70 insertions(+), 2 deletions(-) > >>>>> > >>>>> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c > >>>>> index e68cd87998c8..c8e145031429 100644 > >>>>> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c > >>>>> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c > >>>>> @@ -15,6 +15,7 @@ > >>>>> #include <linux/module.h> > >>>>> #include <linux/of.h> > >>>>> #include <linux/of_device.h> > >>>>> +#include <linux/pm_runtime.h> > >>>>> #include <linux/reset.h> > >>>>> #include <linux/sizes.h> > >>>>> > >>>>> @@ -548,9 +549,13 @@ static int dwcmshc_probe(struct platform_device *pdev) > >>>>> > >>>>> host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY; > >>>>> > >>>>> + pm_runtime_get_noresume(dev); > >>>>> + pm_runtime_set_active(dev); > >>>>> + pm_runtime_enable(dev); > >>>>> + > >>>>> err = sdhci_setup_host(host); > >>>>> if (err) > >>>>> - goto err_clk; > >>>>> + goto err_rpm; > >>>>> > >>>>> if (rk_priv) > >>>>> dwcmshc_rk35xx_postinit(host, priv); > >>>>> @@ -559,10 +564,15 @@ static int dwcmshc_probe(struct platform_device *pdev) > >>>>> if (err) > >>>>> goto err_setup_host; > >>>>> > >>>>> + pm_runtime_put(dev); > >>>>> + > >>>>> return 0; > >>>>> > >>>>> err_setup_host: > >>>>> sdhci_cleanup_host(host); > >>>>> +err_rpm: > >>>>> + pm_runtime_disable(dev); > >>>>> + pm_runtime_put_noidle(dev); > >>>>> err_clk: > >>>>> clk_disable_unprepare(pltfm_host->clk); > >>>>> clk_disable_unprepare(priv->bus_clk); > >>>>> @@ -606,6 +616,12 @@ static int dwcmshc_suspend(struct device *dev) > >>>>> if (ret) > >>>>> return ret; > >>>>> > >>>>> + ret = pm_runtime_force_suspend(dev); > >>>>> + if (ret) { > >>>>> + sdhci_resume_host(host); > >>>>> + return ret; > >>>>> + } > >>>> > >>>> Since you are only using the runtime PM callbacks to turn off the card > >>>> clock via SDHCI_CLOCK_CONTROL, pm_runtime_force_suspend() and > >>>> pm_runtime_force_resume() are not needed at all. > >>> > >>> Right, it can be done without these too. > >>> > >>>> > >>>> sdhci_suspend_host() does not care if SDHCI_CLOCK_CARD_EN is on or off. > >>>> (And you are disabling pltfm_host->clk and priv->bus_clk, so presumably > >>>> the result is no clock either way) > >>>> > >>>> sdhci_resume_host() does not restore state unless > >>>> SDHCI_QUIRK2_HOST_OFF_CARD_ON is used, it just resets, so the internal clock > >>>> SDHCI_CLOCK_INT_EN is off which is consistent with either runtime suspended > >>>> or runtime resumed. > >>> > >>> Even if this may work, to me, it doesn't look like good practice for > >>> how to use runtime PM in combination with system wide suspend/resume. > >>> > >>> The point is, sdhci_suspend|resume_host() may end up reading/writing > >>> to sdhci registers - and we should *not* allow that (because it may > >>> not always work), unless the sdhci controller has been runtime resumed > >>> first, right? > >> > >> I am OK with drivers that just want to use runtime PM to turn off a > >> functional clock. sdhci-tegra.c is also doing that although using the > >> clock framework. > > > > Yes, I agree. At least this works for SoC specific drivers. > > > >> > >> Certainly that approach assumes that the host controller's power state > >> is not changed due to runtime PM. > >> > >> To ensure that the host controller is runtime resumed before calling > >> sdhci_suspend_host(), we can just call pm_runtime_resume() I think. > > > > Yes, that was kind of what I proposed in the other thread as option 1) > > (except for the replacement of pm_runtime_force_suspend|resume). > > > > Although, to be clear I would probably use pm_runtime_get_sync() > > instead, to make sure the usage count is incremented too. > > In that case, a matching pm_runtime_put() is needed also at the > end of the resume callback. Yes, of course. Or depending if we are using the force_suspend|resume helper, a pm_runtime_put_noidle is sufficient after pm_runtime_force_suspend() has been called. [...] Kind regards Uffe
> -----Original Message----- > From: Ulf Hansson <ulf.hansson@linaro.org> > Sent: Friday, August 11, 2023 4:36 AM > To: Adrian Hunter <adrian.hunter@intel.com> > Cc: Liming Sun <limings@nvidia.com>; David Thompson > <davthompson@nvidia.com>; Shawn Lin <shawn.lin@rock-chips.com>; linux- > mmc@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH v7] mmc: sdhci-of-dwcmshc: Add runtime PM operations > > On Fri, 11 Aug 2023 at 07:57, Adrian Hunter <adrian.hunter@intel.com> > wrote: > > > > On 10/08/23 19:34, Ulf Hansson wrote: > > > On Thu, 10 Aug 2023 at 14:44, Adrian Hunter <adrian.hunter@intel.com> > wrote: > > >> > > >> On 10/08/23 13:21, Ulf Hansson wrote: > > >>> On Thu, 10 Aug 2023 at 10:13, Adrian Hunter > <adrian.hunter@intel.com> wrote: > > >>>> > > >>>> On 8/08/23 23:23, Liming Sun wrote: > > >>>>> This commit implements the runtime PM operations to disable eMMC > > >>>>> card clock when idle. > > >>>>> > > >>>>> Reviewed-by: David Thompson <davthompson@nvidia.com> > > >>>>> Signed-off-by: Liming Sun <limings@nvidia.com> > > >>>>> --- > > >>>>> v6->v7: > > >>>>> - Address Ulf's comment; > > >>>>> v5->v6: > > >>>>> - Address Adrian's more comments and add coordination between > > >>>>> runtime PM and system PM; > > >>>>> v4->v5: > > >>>>> - Address Adrian's comment to move the pm_enable to the end to > > >>>>> avoid race; > > >>>>> v3->v4: > > >>>>> - Fix compiling reported by 'kernel test robot'; > > >>>>> v2->v3: > > >>>>> - Revise the commit message; > > >>>>> v1->v2: > > >>>>> Updates for comments from Ulf: > > >>>>> - Make the runtime PM logic generic for sdhci-of-dwcmshc; > > >>>>> v1: Initial version. > > >>>>> --- > > >>>>> drivers/mmc/host/sdhci-of-dwcmshc.c | 72 > ++++++++++++++++++++++++++++- > > >>>>> 1 file changed, 70 insertions(+), 2 deletions(-) > > >>>>> > > >>>>> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c > b/drivers/mmc/host/sdhci-of-dwcmshc.c > > >>>>> index e68cd87998c8..c8e145031429 100644 > > >>>>> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c > > >>>>> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c > > >>>>> @@ -15,6 +15,7 @@ > > >>>>> #include <linux/module.h> > > >>>>> #include <linux/of.h> > > >>>>> #include <linux/of_device.h> > > >>>>> +#include <linux/pm_runtime.h> > > >>>>> #include <linux/reset.h> > > >>>>> #include <linux/sizes.h> > > >>>>> > > >>>>> @@ -548,9 +549,13 @@ static int dwcmshc_probe(struct > platform_device *pdev) > > >>>>> > > >>>>> host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY; > > >>>>> > > >>>>> + pm_runtime_get_noresume(dev); > > >>>>> + pm_runtime_set_active(dev); > > >>>>> + pm_runtime_enable(dev); > > >>>>> + > > >>>>> err = sdhci_setup_host(host); > > >>>>> if (err) > > >>>>> - goto err_clk; > > >>>>> + goto err_rpm; > > >>>>> > > >>>>> if (rk_priv) > > >>>>> dwcmshc_rk35xx_postinit(host, priv); > > >>>>> @@ -559,10 +564,15 @@ static int dwcmshc_probe(struct > platform_device *pdev) > > >>>>> if (err) > > >>>>> goto err_setup_host; > > >>>>> > > >>>>> + pm_runtime_put(dev); > > >>>>> + > > >>>>> return 0; > > >>>>> > > >>>>> err_setup_host: > > >>>>> sdhci_cleanup_host(host); > > >>>>> +err_rpm: > > >>>>> + pm_runtime_disable(dev); > > >>>>> + pm_runtime_put_noidle(dev); > > >>>>> err_clk: > > >>>>> clk_disable_unprepare(pltfm_host->clk); > > >>>>> clk_disable_unprepare(priv->bus_clk); > > >>>>> @@ -606,6 +616,12 @@ static int dwcmshc_suspend(struct device > *dev) > > >>>>> if (ret) > > >>>>> return ret; > > >>>>> > > >>>>> + ret = pm_runtime_force_suspend(dev); > > >>>>> + if (ret) { > > >>>>> + sdhci_resume_host(host); > > >>>>> + return ret; > > >>>>> + } > > >>>> > > >>>> Since you are only using the runtime PM callbacks to turn off the card > > >>>> clock via SDHCI_CLOCK_CONTROL, pm_runtime_force_suspend() and > > >>>> pm_runtime_force_resume() are not needed at all. > > >>> > > >>> Right, it can be done without these too. > > >>> > > >>>> > > >>>> sdhci_suspend_host() does not care if SDHCI_CLOCK_CARD_EN is on or > off. > > >>>> (And you are disabling pltfm_host->clk and priv->bus_clk, so > presumably > > >>>> the result is no clock either way) > > >>>> > > >>>> sdhci_resume_host() does not restore state unless > > >>>> SDHCI_QUIRK2_HOST_OFF_CARD_ON is used, it just resets, so the > internal clock > > >>>> SDHCI_CLOCK_INT_EN is off which is consistent with either runtime > suspended > > >>>> or runtime resumed. > > >>> > > >>> Even if this may work, to me, it doesn't look like good practice for > > >>> how to use runtime PM in combination with system wide > suspend/resume. > > >>> > > >>> The point is, sdhci_suspend|resume_host() may end up reading/writing > > >>> to sdhci registers - and we should *not* allow that (because it may > > >>> not always work), unless the sdhci controller has been runtime resumed > > >>> first, right? > > >> > > >> I am OK with drivers that just want to use runtime PM to turn off a > > >> functional clock. sdhci-tegra.c is also doing that although using the > > >> clock framework. > > > > > > Yes, I agree. At least this works for SoC specific drivers. > > > > > >> > > >> Certainly that approach assumes that the host controller's power state > > >> is not changed due to runtime PM. > > >> > > >> To ensure that the host controller is runtime resumed before calling > > >> sdhci_suspend_host(), we can just call pm_runtime_resume() I think. > > > > > > Yes, that was kind of what I proposed in the other thread as option 1) > > > (except for the replacement of pm_runtime_force_suspend|resume). > > > > > > Although, to be clear I would probably use pm_runtime_get_sync() > > > instead, to make sure the usage count is incremented too. > > > > In that case, a matching pm_runtime_put() is needed also at the > > end of the resume callback. > > Yes, of course. Or depending if we are using the force_suspend|resume > helper, a pm_runtime_put_noidle is sufficient after > pm_runtime_force_suspend() has been called. Thanks Ulf/Adrian! Plan to upload v8 with the following changes: - Remove pm_runtime_force_suspend/resume() from dwcmshc_suspend()/dwcmshc_resume() (Adrian's comment). - Add comments for dwcmshc_resume()/dwcmshc_suspend(); (According to Andrian's comment). - Add pm_runtime_get_sync()/pm_runtime_put() in dwcmshc_suspend(), which is Ulf option-1. Option-2 seems more efficient, but it involves more changes and I couldn't test the impact on other SoC. Maybe for future enhancement? > > [...] > > Kind regards > Uffe
[...] > > > >>>> > > > >>>> Since you are only using the runtime PM callbacks to turn off the card > > > >>>> clock via SDHCI_CLOCK_CONTROL, pm_runtime_force_suspend() and > > > >>>> pm_runtime_force_resume() are not needed at all. > > > >>> > > > >>> Right, it can be done without these too. > > > >>> > > > >>>> > > > >>>> sdhci_suspend_host() does not care if SDHCI_CLOCK_CARD_EN is on or > > off. > > > >>>> (And you are disabling pltfm_host->clk and priv->bus_clk, so > > presumably > > > >>>> the result is no clock either way) > > > >>>> > > > >>>> sdhci_resume_host() does not restore state unless > > > >>>> SDHCI_QUIRK2_HOST_OFF_CARD_ON is used, it just resets, so the > > internal clock > > > >>>> SDHCI_CLOCK_INT_EN is off which is consistent with either runtime > > suspended > > > >>>> or runtime resumed. > > > >>> > > > >>> Even if this may work, to me, it doesn't look like good practice for > > > >>> how to use runtime PM in combination with system wide > > suspend/resume. > > > >>> > > > >>> The point is, sdhci_suspend|resume_host() may end up reading/writing > > > >>> to sdhci registers - and we should *not* allow that (because it may > > > >>> not always work), unless the sdhci controller has been runtime resumed > > > >>> first, right? > > > >> > > > >> I am OK with drivers that just want to use runtime PM to turn off a > > > >> functional clock. sdhci-tegra.c is also doing that although using the > > > >> clock framework. > > > > > > > > Yes, I agree. At least this works for SoC specific drivers. > > > > > > > >> > > > >> Certainly that approach assumes that the host controller's power state > > > >> is not changed due to runtime PM. > > > >> > > > >> To ensure that the host controller is runtime resumed before calling > > > >> sdhci_suspend_host(), we can just call pm_runtime_resume() I think. > > > > > > > > Yes, that was kind of what I proposed in the other thread as option 1) > > > > (except for the replacement of pm_runtime_force_suspend|resume). > > > > > > > > Although, to be clear I would probably use pm_runtime_get_sync() > > > > instead, to make sure the usage count is incremented too. > > > > > > In that case, a matching pm_runtime_put() is needed also at the > > > end of the resume callback. > > > > Yes, of course. Or depending if we are using the force_suspend|resume > > helper, a pm_runtime_put_noidle is sufficient after > > pm_runtime_force_suspend() has been called. > > Thanks Ulf/Adrian! Plan to upload v8 with the following changes: > - Remove pm_runtime_force_suspend/resume() from dwcmshc_suspend()/dwcmshc_resume() (Adrian's comment). > - Add comments for dwcmshc_resume()/dwcmshc_suspend(); > (According to Andrian's comment). > - Add pm_runtime_get_sync()/pm_runtime_put() in dwcmshc_suspend(), which is Ulf option-1. Option-2 seems more efficient, but it involves more changes and I couldn't test the impact on other SoC. Maybe for future enhancement? That works for me! Kind regards Uffe
diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c index e68cd87998c8..c8e145031429 100644 --- a/drivers/mmc/host/sdhci-of-dwcmshc.c +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c @@ -15,6 +15,7 @@ #include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> +#include <linux/pm_runtime.h> #include <linux/reset.h> #include <linux/sizes.h> @@ -548,9 +549,13 @@ static int dwcmshc_probe(struct platform_device *pdev) host->mmc->caps |= MMC_CAP_WAIT_WHILE_BUSY; + pm_runtime_get_noresume(dev); + pm_runtime_set_active(dev); + pm_runtime_enable(dev); + err = sdhci_setup_host(host); if (err) - goto err_clk; + goto err_rpm; if (rk_priv) dwcmshc_rk35xx_postinit(host, priv); @@ -559,10 +564,15 @@ static int dwcmshc_probe(struct platform_device *pdev) if (err) goto err_setup_host; + pm_runtime_put(dev); + return 0; err_setup_host: sdhci_cleanup_host(host); +err_rpm: + pm_runtime_disable(dev); + pm_runtime_put_noidle(dev); err_clk: clk_disable_unprepare(pltfm_host->clk); clk_disable_unprepare(priv->bus_clk); @@ -606,6 +616,12 @@ static int dwcmshc_suspend(struct device *dev) if (ret) return ret; + ret = pm_runtime_force_suspend(dev); + if (ret) { + sdhci_resume_host(host); + return ret; + } + clk_disable_unprepare(pltfm_host->clk); if (!IS_ERR(priv->bus_clk)) clk_disable_unprepare(priv->bus_clk); @@ -625,6 +641,10 @@ static int dwcmshc_resume(struct device *dev) struct rk35xx_priv *rk_priv = priv->priv; int ret; + ret = pm_runtime_force_resume(dev); + if (ret) + return ret; + ret = clk_prepare_enable(pltfm_host->clk); if (ret) return ret; @@ -646,7 +666,55 @@ static int dwcmshc_resume(struct device *dev) } #endif -static SIMPLE_DEV_PM_OPS(dwcmshc_pmops, dwcmshc_suspend, dwcmshc_resume); +#ifdef CONFIG_PM + +static void dwcmshc_enable_card_clk(struct sdhci_host *host) +{ + u16 ctrl; + + ctrl = sdhci_readw(host, SDHCI_CLOCK_CONTROL); + if ((ctrl & SDHCI_CLOCK_INT_EN) && !(ctrl & SDHCI_CLOCK_CARD_EN)) { + ctrl |= SDHCI_CLOCK_CARD_EN; + sdhci_writew(host, ctrl, SDHCI_CLOCK_CONTROL); + } +} + +static void dwcmshc_disable_card_clk(struct sdhci_host *host) +{ + u16 ctrl; + + ctrl = sdhci_readw(host, SDHCI_CLOCK_CONTROL); + if (ctrl & SDHCI_CLOCK_CARD_EN) { + ctrl &= ~SDHCI_CLOCK_CARD_EN; + sdhci_writew(host, ctrl, SDHCI_CLOCK_CONTROL); + } +} + +static int dwcmshc_runtime_suspend(struct device *dev) +{ + struct sdhci_host *host = dev_get_drvdata(dev); + + dwcmshc_disable_card_clk(host); + + return 0; +} + +static int dwcmshc_runtime_resume(struct device *dev) +{ + struct sdhci_host *host = dev_get_drvdata(dev); + + dwcmshc_enable_card_clk(host); + + return 0; +} + +#endif + +static const struct dev_pm_ops dwcmshc_pmops = { + SET_SYSTEM_SLEEP_PM_OPS(dwcmshc_suspend, dwcmshc_resume) + SET_RUNTIME_PM_OPS(dwcmshc_runtime_suspend, + dwcmshc_runtime_resume, NULL) +}; static struct platform_driver sdhci_dwcmshc_driver = { .driver = {