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Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.14.0 Subject: Re: [PATCH v7] mmc: sdhci-of-dwcmshc: Add runtime PM operations Content-Language: en-US To: Liming Sun , Ulf Hansson , David Thompson , Shawn Lin Cc: linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org References: <79137159a833c164ea8ea3f05d8d6d9537db2f42.1683747334.git.limings@nvidia.com> <20230808202319.191434-1-limings@nvidia.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <20230808202319.191434-1-limings@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > Signed-off-by: Liming Sun > --- > 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 > #include > #include > +#include > #include > #include > > @@ -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. 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. So it just needs some comments, for example: +/* + * Note, runtime suspend changes only SDHCI_CLOCK_CARD_EN which has no effect on + * system suspend. + */ static int dwcmshc_suspend(struct device *dev) +/* + * Note, system resume leaves SDHCI_CLOCK_INT_EN off which is consistent with + * either runtime suspended or runtime resumed. + */ static int dwcmshc_resume(struct device *dev) > + > 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 = {