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Commit bd1dffb1 authored by Krzysztof Kozlowski's avatar Krzysztof Kozlowski Committed by Herbert Xu
Browse files

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: default avatarKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent d7fd6075

drivers/char/hw_random/exynos-rng.c

+35 −7
Original line number Diff line number Diff line
@@ -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		= {