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hwrng: exynos - Fix missing configuration after suspend to RAM 

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@samsung.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Krzysztof Kozlowski 2015-10-19 13:37:41 +09:00 committed by Herbert Xu
parent d7fd6075a2
commit bd1dffb142
1 changed files with 35 additions and 7 deletions
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42
drivers/char/hw_random/exynos-rng.c
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@ -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 = {