Re: [PATCH v3 1/4] mmc: sdhci-cadence: add suspend / resume support

From: Adrian Hunter
Date: Mon Aug 21 2017 - 07:55:41 EST


On 15/08/17 18:45, Masahiro Yamada wrote:
> Currently, the probe function initializes the PHY, but PHY settings
> are lost during the sleep state. Restore the PHY registers when
> resuming.
>
> To facilitate this, split sdhci_cdns_phy_init() into the DT parse
> part and PHY update part so that the latter can be invoked from the
> resume hook.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>

Just one comment about using clk_disable_unprepare() on the error path.

> ---
>
> Changes in v3:
> - Use #ifdef CONFIG_PM_SLEEP instead of __maybe_unused
> - Add own sdhci_cdns_suspend implementation to not depend on
> the core change
>
> Changes in v2: None
>
> drivers/mmc/host/sdhci-cadence.c | 97 ++++++++++++++++++++++++++++++++++++----
> 1 file changed, 88 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
> index 19d5698244b5..751ba706bf03 100644
> --- a/drivers/mmc/host/sdhci-cadence.c
> +++ b/drivers/mmc/host/sdhci-cadence.c
> @@ -67,9 +67,16 @@
> */
> #define SDHCI_CDNS_MAX_TUNING_LOOP 40
>
> +struct sdhci_cdns_phy_param {
> + u8 addr;
> + u8 data;
> +};
> +
> struct sdhci_cdns_priv {
> void __iomem *hrs_addr;
> bool enhanced_strobe;
> + unsigned int nr_phy_params;
> + struct sdhci_cdns_phy_param phy_params[0];
> };
>
> struct sdhci_cdns_phy_cfg {
> @@ -115,9 +122,22 @@ static int sdhci_cdns_write_phy_reg(struct sdhci_cdns_priv *priv,
> return 0;
> }
>
> -static int sdhci_cdns_phy_init(struct device_node *np,
> - struct sdhci_cdns_priv *priv)
> +static unsigned int sdhci_cdns_phy_param_count(struct device_node *np)
> {
> + unsigned int count = 0;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(sdhci_cdns_phy_cfgs); i++)
> + if (of_property_read_bool(np, sdhci_cdns_phy_cfgs[i].property))
> + count++;
> +
> + return count;
> +}
> +
> +static void sdhci_cdns_phy_param_parse(struct device_node *np,
> + struct sdhci_cdns_priv *priv)
> +{
> + struct sdhci_cdns_phy_param *p = priv->phy_params;
> u32 val;
> int ret, i;
>
> @@ -127,9 +147,19 @@ static int sdhci_cdns_phy_init(struct device_node *np,
> if (ret)
> continue;
>
> - ret = sdhci_cdns_write_phy_reg(priv,
> - sdhci_cdns_phy_cfgs[i].addr,
> - val);
> + p->addr = sdhci_cdns_phy_cfgs[i].addr;
> + p->data = val;
> + p++;
> + }
> +}
> +
> +static int sdhci_cdns_phy_init(struct sdhci_cdns_priv *priv)
> +{
> + int ret, i;
> +
> + for (i = 0; i < priv->nr_phy_params; i++) {
> + ret = sdhci_cdns_write_phy_reg(priv, priv->phy_params[i].addr,
> + priv->phy_params[i].data);
> if (ret)
> return ret;
> }
> @@ -302,6 +332,8 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> struct sdhci_pltfm_host *pltfm_host;
> struct sdhci_cdns_priv *priv;
> struct clk *clk;
> + size_t priv_size;
> + unsigned int nr_phy_params;
> int ret;
> struct device *dev = &pdev->dev;
>
> @@ -313,7 +345,9 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> if (ret)
> return ret;
>
> - host = sdhci_pltfm_init(pdev, &sdhci_cdns_pltfm_data, sizeof(*priv));
> + nr_phy_params = sdhci_cdns_phy_param_count(dev->of_node);
> + priv_size = sizeof(*priv) + sizeof(priv->phy_params[0]) * nr_phy_params;
> + host = sdhci_pltfm_init(pdev, &sdhci_cdns_pltfm_data, priv_size);
> if (IS_ERR(host)) {
> ret = PTR_ERR(host);
> goto disable_clk;
> @@ -322,7 +356,8 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> pltfm_host = sdhci_priv(host);
> pltfm_host->clk = clk;
>
> - priv = sdhci_cdns_priv(host);
> + priv = sdhci_pltfm_priv(pltfm_host);
> + priv->nr_phy_params = nr_phy_params;
> priv->hrs_addr = host->ioaddr;
> priv->enhanced_strobe = false;
> host->ioaddr += SDHCI_CDNS_SRS_BASE;
> @@ -336,7 +371,9 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> if (ret)
> goto free;
>
> - ret = sdhci_cdns_phy_init(dev->of_node, priv);
> + sdhci_cdns_phy_param_parse(dev->of_node, priv);
> +
> + ret = sdhci_cdns_phy_init(priv);
> if (ret)
> goto free;
>
> @@ -353,6 +390,48 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> return ret;
> }
>
> +#ifdef CONFIG_PM_SLEEP
> +static int sdhci_cdns_suspend(struct device *dev)
> +{
> + struct sdhci_host *host = dev_get_drvdata(dev);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + int ret;
> +
> + if (host->tuning_mode != SDHCI_TUNING_MODE_3)
> + mmc_retune_needed(host->mmc);
> +
> + ret = sdhci_suspend_host(host);
> + if (ret)
> + return ret;
> +
> + clk_disable_unprepare(pltfm_host->clk);
> +
> + return 0;
> +}
> +
> +static int sdhci_cdns_resume(struct device *dev)
> +{
> + struct sdhci_host *host = dev_get_drvdata(dev);
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_cdns_priv *priv = sdhci_pltfm_priv(pltfm_host);
> + int ret;
> +
> + ret = clk_prepare_enable(pltfm_host->clk);
> + if (ret)
> + return ret;
> +
> + ret = sdhci_cdns_phy_init(priv);
> + if (ret)
> + return ret;

Perhaps clk_disable_unprepare(pltfm_host->clk)

> +
> + return sdhci_resume_host(host);

Ditto on error.

> +}
> +#endif
> +
> +static const struct dev_pm_ops sdhci_cdns_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(sdhci_cdns_suspend, sdhci_cdns_resume)
> +};
> +
> static const struct of_device_id sdhci_cdns_match[] = {
> { .compatible = "socionext,uniphier-sd4hc" },
> { .compatible = "cdns,sd4hc" },
> @@ -363,7 +442,7 @@ MODULE_DEVICE_TABLE(of, sdhci_cdns_match);
> static struct platform_driver sdhci_cdns_driver = {
> .driver = {
> .name = "sdhci-cdns",
> - .pm = &sdhci_pltfm_pmops,
> + .pm = &sdhci_cdns_pm_ops,
> .of_match_table = sdhci_cdns_match,
> },
> .probe = sdhci_cdns_probe,
>