linux-kernel - Re: [PATCH v10 2/2] This commit implements the runtime PM operations to disable eMMC card clock when idle.

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Message-ID: <CAPDyKFpQOTdrOm2FkJL+EoDhq9u4puKVnnTfFGA82Nmy9UTibA@mail.gmail.com>
Date:   Thu, 24 Aug 2023 13:00:30 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Liming Sun <limings@...dia.com>
Cc:     Adrian Hunter <adrian.hunter@...el.com>,
        David Thompson <davthompson@...dia.com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 2/2] This commit implements the runtime PM operations
 to disable eMMC card clock when idle.

On Tue, 22 Aug 2023 at 21:59, Liming Sun <limings@...dia.com> wrote:
>
> Reviewed-by: David Thompson <davthompson@...dia.com>
> Signed-off-by: Liming Sun <limings@...dia.com>

Applied for next (I amended the patch according to Adrian's
suggestions), thanks!

Kind regards
Uffe


> ---
> v9->v10:
>     - Simplify the changes with pm_runtime_resume() in
>       dwcmshc_suspend().
> v8->v9:
>     - Address Adrian's comment to do the pm_runtime_put() in
>       dwcmshc_resume() instead; Error path changes not included yet.
> v7->v8:
>     - Address Ulf's comment (option-1);
>     - Updates for Adrian's comment to remove the force_suspend/resume
>       in dwcmshc_resume()/dwcmshc_suspend(); Add comments for
>       dwcmshc_resume()/dwcmshc_suspend();
> 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 | 64 ++++++++++++++++++++++++++++-
>  1 file changed, 62 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
> index bc332a035032..3a3bae6948a8 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/platform_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);
> @@ -600,6 +610,8 @@ static int dwcmshc_suspend(struct device *dev)
>         struct rk35xx_priv *rk_priv = priv->priv;
>         int ret;
>
> +       pm_runtime_resume(dev);
> +
>         ret = sdhci_suspend_host(host);
>         if (ret)
>                 return ret;
> @@ -659,7 +671,55 @@ 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 = {
> --
> 2.30.1
>