After suspend to RAM the device stopped to work with ETIMEDOUT error:
$ dd if=/dev/hwrng of=/dev/null bs=1 count=16
dd: reading `/dev/hwrng': Connection timed out
In the STATUS register the bits #5 (PRNG_DONE) and #1
(SEED_SETTING_DONE) were not set. Instead PRNG_ERROR (seventh bit) was
high.
After each system suspend initialize the seed to fix the error.
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@xxxxxxxxxxx>
---
drivers/char/hw_random/exynos-rng.c | 42 ++++++++++++++++++++++++++++++-------
1 file changed, 35 insertions(+), 7 deletions(-)
diff --git a/drivers/char/hw_random/exynos-rng.c b/drivers/char/hw_random/exynos-rng.c
index dfaaaafb8ddd..162adbda1b70 100644
--- a/drivers/char/hw_random/exynos-rng.c
+++ b/drivers/char/hw_random/exynos-rng.c
@@ -53,15 +53,11 @@ static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
__raw_writel(val, rng->mem + offset);
}
-static int exynos_init(struct hwrng *rng)
+static int exynos_rng_configure(struct exynos_rng *exynos_rng)
{
- struct exynos_rng *exynos_rng = container_of(rng,
- struct exynos_rng, rng);
int i;
int ret = 0;
- pm_runtime_get_sync(exynos_rng->dev);
-
for (i = 0 ; i < 5 ; i++)
exynos_rng_writel(exynos_rng, jiffies,
EXYNOS_PRNG_SEED_OFFSET + 4*i);
@@ -70,6 +66,17 @@ static int exynos_init(struct hwrng *rng)
& SEED_SETTING_DONE))
ret = -EIO;
+ return ret;
+}
+
+static int exynos_init(struct hwrng *rng)
+{
+ struct exynos_rng *exynos_rng = container_of(rng,
+ struct exynos_rng, rng);
+ int ret = 0;
+
+ pm_runtime_get_sync(exynos_rng->dev);
+ ret = exynos_rng_configure(exynos_rng);
pm_runtime_put_noidle(exynos_rng->dev);
return ret;
@@ -155,10 +162,31 @@ static int exynos_rng_runtime_resume(struct device *dev)
return clk_prepare_enable(exynos_rng->clk);
}
+
+static int exynos_rng_suspend(struct device *dev)
+{
+ return pm_runtime_force_suspend(dev);
+}
+
+static int exynos_rng_resume(struct device *dev)
+{
+ struct platform_device *pdev = to_platform_device(dev);
+ struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
+ int ret;
+
+ ret = pm_runtime_force_resume(dev);
+ if (ret)
+ return ret;
+
+ return exynos_rng_configure(exynos_rng);
+}
#endif
-static UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
- exynos_rng_runtime_resume, NULL);
+static const struct dev_pm_ops exynos_rng_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(exynos_rng_suspend, exynos_rng_resume)
+ SET_RUNTIME_PM_OPS(exynos_rng_runtime_suspend,
+ exynos_rng_runtime_resume, NULL)
+};
static struct platform_driver exynos_rng_driver = {
.driver = {
--
1.9.1
--
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