Re: [PATCH] Revert "mmc: sdhci-xenon: add runtime pm support and reimplement standby"

[Ulf Hansson <ulf.hansson@linaro.org>]

On Wed, 13 May 2020 at 11:47, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote:
>
> This reverts commit a027b2c5fed78851e69fab395b02d127a7759fc7.
>
> The HW supports auto clock gating, so it's useless to do runtime pm
> in software.

Runtime PM isn't soley about clock gating. Moreover it manages the
"pltfm_host->clk", which means even if the controller supports auto
clock gating, gating/ungating the externally provided clock still
makes sense.

Kind regards
Uffe

>
> Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
> ---
>  drivers/mmc/host/sdhci-xenon.c | 87 +++++++---------------------------
>  drivers/mmc/host/sdhci-xenon.h |  1 -
>  2 files changed, 16 insertions(+), 72 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-xenon.c b/drivers/mmc/host/sdhci-xenon.c
> index 4703cd540c7f..85414e13e7ea 100644
> --- a/drivers/mmc/host/sdhci-xenon.c
> +++ b/drivers/mmc/host/sdhci-xenon.c
> @@ -15,8 +15,6 @@
>  #include <linux/ktime.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> -#include <linux/pm.h>
> -#include <linux/pm_runtime.h>
>
>  #include "sdhci-pltfm.h"
>  #include "sdhci-xenon.h"
> @@ -539,24 +537,13 @@ static int xenon_probe(struct platform_device *pdev)
>         if (err)
>                 goto err_clk_axi;
>
> -       pm_runtime_get_noresume(&pdev->dev);
> -       pm_runtime_set_active(&pdev->dev);
> -       pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
> -       pm_runtime_use_autosuspend(&pdev->dev);
> -       pm_runtime_enable(&pdev->dev);
> -       pm_suspend_ignore_children(&pdev->dev, 1);
> -
>         err = sdhci_add_host(host);
>         if (err)
>                 goto remove_sdhc;
>
> -       pm_runtime_put_autosuspend(&pdev->dev);
> -
>         return 0;
>
>  remove_sdhc:
> -       pm_runtime_disable(&pdev->dev);
> -       pm_runtime_put_noidle(&pdev->dev);
>         xenon_sdhc_unprepare(host);
>  err_clk_axi:
>         clk_disable_unprepare(priv->axi_clk);
> @@ -573,10 +560,6 @@ static int xenon_remove(struct platform_device *pdev)
>         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>         struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
>
> -       pm_runtime_get_sync(&pdev->dev);
> -       pm_runtime_disable(&pdev->dev);
> -       pm_runtime_put_noidle(&pdev->dev);
> -
>         sdhci_remove_host(host, 0);
>
>         xenon_sdhc_unprepare(host);
> @@ -593,78 +576,40 @@ static int xenon_suspend(struct device *dev)
>  {
>         struct sdhci_host *host = dev_get_drvdata(dev);
>         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> -       struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
>         int ret;
>
> -       ret = pm_runtime_force_suspend(dev);
> +       ret = sdhci_suspend_host(host);
> +       if (ret)
> +               return ret;
>
> -       priv->restore_needed = true;
> +       clk_disable_unprepare(pltfm_host->clk);
>         return ret;
>  }
> -#endif
>
> -#ifdef CONFIG_PM
> -static int xenon_runtime_suspend(struct device *dev)
> +static int xenon_resume(struct device *dev)
>  {
>         struct sdhci_host *host = dev_get_drvdata(dev);
>         struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> -       struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
>         int ret;
>
> -       ret = sdhci_runtime_suspend_host(host);
> +       ret = clk_prepare_enable(pltfm_host->clk);
>         if (ret)
>                 return ret;
>
> -       if (host->tuning_mode != SDHCI_TUNING_MODE_3)
> -               mmc_retune_needed(host->mmc);
> -
> -       clk_disable_unprepare(pltfm_host->clk);
>         /*
> -        * Need to update the priv->clock here, or when runtime resume
> -        * back, phy don't aware the clock change and won't adjust phy
> -        * which will cause cmd err
> +        * If SoCs power off the entire Xenon, registers setting will
> +        * be lost.
> +        * Re-configure Xenon specific register to enable current SDHC
>          */
> -       priv->clock = 0;
> -       return 0;
> -}
> -
> -static int xenon_runtime_resume(struct device *dev)
> -{
> -       struct sdhci_host *host = dev_get_drvdata(dev);
> -       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> -       struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
> -       int ret;
> -
> -       ret = clk_prepare_enable(pltfm_host->clk);
> -       if (ret) {
> -               dev_err(dev, "can't enable mainck\n");
> +       ret = xenon_sdhc_prepare(host);
> +       if (ret)
>                 return ret;
> -       }
> -
> -       if (priv->restore_needed) {
> -               ret = xenon_sdhc_prepare(host);
> -               if (ret)
> -                       goto out;
> -               priv->restore_needed = false;
> -       }
>
> -       ret = sdhci_runtime_resume_host(host, 0);
> -       if (ret)
> -               goto out;
> -       return 0;
> -out:
> -       clk_disable_unprepare(pltfm_host->clk);
> -       return ret;
> +       return sdhci_resume_host(host);
>  }
> -#endif /* CONFIG_PM */
> -
> -static const struct dev_pm_ops sdhci_xenon_dev_pm_ops = {
> -       SET_SYSTEM_SLEEP_PM_OPS(xenon_suspend,
> -                               pm_runtime_force_resume)
> -       SET_RUNTIME_PM_OPS(xenon_runtime_suspend,
> -                          xenon_runtime_resume,
> -                          NULL)
> -};
> +#endif
> +
> +static SIMPLE_DEV_PM_OPS(xenon_pmops, xenon_suspend, xenon_resume);
>
>  static const struct of_device_id sdhci_xenon_dt_ids[] = {
>         { .compatible = "marvell,armada-ap806-sdhci",},
> @@ -678,7 +623,7 @@ static struct platform_driver sdhci_xenon_driver = {
>         .driver = {
>                 .name   = "xenon-sdhci",
>                 .of_match_table = sdhci_xenon_dt_ids,
> -               .pm = &sdhci_xenon_dev_pm_ops,
> +               .pm = &xenon_pmops,
>         },
>         .probe  = xenon_probe,
>         .remove = xenon_remove,
> diff --git a/drivers/mmc/host/sdhci-xenon.h b/drivers/mmc/host/sdhci-xenon.h
> index 593b82d7b68a..2b9b96e51261 100644
> --- a/drivers/mmc/host/sdhci-xenon.h
> +++ b/drivers/mmc/host/sdhci-xenon.h
> @@ -89,7 +89,6 @@ struct xenon_priv {
>          */
>         void            *phy_params;
>         struct xenon_emmc_phy_regs *emmc_phy_regs;
> -       bool restore_needed;
>  };
>
>  int xenon_phy_adj(struct sdhci_host *host, struct mmc_ios *ios);
> --
> 2.26.2
>