[PATCH v6] mmc: sdhci-of-dwcmshc: Add runtime PM operations

Liming Sun
2023-08-04T23:30:41Z

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>
---
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..aaf66358f626 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_sync(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 = {
--
2.30.1