From: Sean Wang <[email protected]>
Add runtime PM support. There will be the benefit on SoCs where the
clock to the RNG used can be shutdown.
Signed-off-by: Sean Wang <[email protected]>
---
drivers/char/hw_random/mtk-rng.c | 42 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/drivers/char/hw_random/mtk-rng.c b/drivers/char/hw_random/mtk-rng.c
index 3a1e1f1..59ded4e 100644
--- a/drivers/char/hw_random/mtk-rng.c
+++ b/drivers/char/hw_random/mtk-rng.c
@@ -25,6 +25,10 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+/* Runtime PM autosuspend timeout: */
+#define RNG_AUTOSUSPEND_TIMEOUT 100
#define USEC_POLL 2
#define TIMEOUT_POLL 20
@@ -90,6 +94,8 @@ static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
struct mtk_rng *priv = to_mtk_rng(rng);
int retval = 0;
+ pm_runtime_get_sync((struct device *)priv->rng.priv);
+
while (max >= sizeof(u32)) {
if (!mtk_rng_wait_ready(rng, wait))
break;
@@ -100,6 +106,9 @@ static int mtk_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
max -= sizeof(u32);
}
+ pm_runtime_mark_last_busy((struct device *)priv->rng.priv);
+ pm_runtime_put_sync_autosuspend((struct device *)priv->rng.priv);
+
return retval || !wait ? retval : -EIO;
}
@@ -120,9 +129,12 @@ static int mtk_rng_probe(struct platform_device *pdev)
return -ENOMEM;
priv->rng.name = pdev->name;
+#ifndef CONFIG_PM
priv->rng.init = mtk_rng_init;
priv->rng.cleanup = mtk_rng_cleanup;
+#endif
priv->rng.read = mtk_rng_read;
+ priv->rng.priv = (unsigned long)&pdev->dev;
priv->clk = devm_clk_get(&pdev->dev, "rng");
if (IS_ERR(priv->clk)) {
@@ -142,11 +154,40 @@ static int mtk_rng_probe(struct platform_device *pdev)
return ret;
}
+ dev_set_drvdata(&pdev->dev, priv);
+ pm_runtime_set_autosuspend_delay(&pdev->dev, RNG_AUTOSUSPEND_TIMEOUT);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
dev_info(&pdev->dev, "registered RNG driver\n");
return 0;
}
+#ifdef CONFIG_PM
+static int mtk_rng_runtime_suspend(struct device *dev)
+{
+ struct mtk_rng *priv = dev_get_drvdata(dev);
+
+ mtk_rng_cleanup(&priv->rng);
+
+ return 0;
+}
+
+static int mtk_rng_runtime_resume(struct device *dev)
+{
+ struct mtk_rng *priv = dev_get_drvdata(dev);
+
+ return mtk_rng_init(&priv->rng);
+}
+
+static UNIVERSAL_DEV_PM_OPS(mtk_rng_pm_ops, mtk_rng_runtime_suspend,
+ mtk_rng_runtime_resume, NULL);
+#define MTK_RNG_PM_OPS (&mtk_rng_pm_ops)
+#else /* CONFIG_PM */
+#define MTK_RNG_PM_OPS NULL
+#endif /* CONFIG_PM */
+
static const struct of_device_id mtk_rng_match[] = {
{ .compatible = "mediatek,generic-rng" },
{ .compatible = "mediatek,mt7623-rng" },
@@ -158,6 +199,7 @@ static int mtk_rng_probe(struct platform_device *pdev)
.probe = mtk_rng_probe,
.driver = {
.name = MTK_RNG_DEV,
+ .pm = MTK_RNG_PM_OPS,
.of_match_table = mtk_rng_match,
},
};
--
1.9.1