--- zzzz-none-000/linux-3.10.107/drivers/char/hw_random/exynos-rng.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/drivers/char/hw_random/exynos-rng.c	2021-02-04 17:41:59.000000000 +0000
@@ -22,7 +22,6 @@
 #include <linux/hw_random.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/init.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
 #include <linux/clk.h>
@@ -54,15 +53,11 @@
 	__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);
@@ -71,6 +66,17 @@
 						 & 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;
@@ -82,23 +88,30 @@
 	struct exynos_rng *exynos_rng = container_of(rng,
 						struct exynos_rng, rng);
 	u32 *data = buf;
+	int retry = 100;
+	int ret = 4;
 
 	pm_runtime_get_sync(exynos_rng->dev);
 
 	exynos_rng_writel(exynos_rng, PRNG_START, 0);
 
 	while (!(exynos_rng_readl(exynos_rng,
-			EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
+			EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE) && --retry)
 		cpu_relax();
+	if (!retry) {
+		ret = -ETIMEDOUT;
+		goto out;
+	}
 
 	exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
 
 	*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
 
+out:
 	pm_runtime_mark_last_busy(exynos_rng->dev);
-	pm_runtime_autosuspend(exynos_rng->dev);
+	pm_runtime_put_sync_autosuspend(exynos_rng->dev);
 
-	return 4;
+	return ret;
 }
 
 static int exynos_rng_probe(struct platform_device *pdev)
@@ -133,7 +146,7 @@
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_enable(&pdev->dev);
 
-	ret = hwrng_register(&exynos_rng->rng);
+	ret = devm_hwrng_register(&pdev->dev, &exynos_rng->rng);
 	if (ret) {
 		pm_runtime_dont_use_autosuspend(&pdev->dev);
 		pm_runtime_disable(&pdev->dev);
@@ -142,46 +155,65 @@
 	return ret;
 }
 
-static int exynos_rng_remove(struct platform_device *pdev)
+#ifdef CONFIG_PM
+static int exynos_rng_runtime_suspend(struct device *dev)
 {
+	struct platform_device *pdev = to_platform_device(dev);
 	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
 
-	hwrng_unregister(&exynos_rng->rng);
+	clk_disable_unprepare(exynos_rng->clk);
 
 	return 0;
 }
 
-#if defined(CONFIG_PM_SLEEP) || defined(CONFIG_PM_RUNTIME)
-static int exynos_rng_runtime_suspend(struct device *dev)
+static int exynos_rng_runtime_resume(struct device *dev)
 {
 	struct platform_device *pdev = to_platform_device(dev);
 	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
 
-	clk_disable_unprepare(exynos_rng->clk);
+	return clk_prepare_enable(exynos_rng->clk);
+}
 
-	return 0;
+static int exynos_rng_suspend(struct device *dev)
+{
+	return pm_runtime_force_suspend(dev);
 }
 
-static int exynos_rng_runtime_resume(struct device *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;
 
-	return clk_prepare_enable(exynos_rng->clk);
+	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 const struct of_device_id exynos_rng_dt_match[] = {
+	{
+		.compatible = "samsung,exynos4-rng",
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(of, exynos_rng_dt_match);
 
 static struct platform_driver exynos_rng_driver = {
 	.driver		= {
 		.name	= "exynos-rng",
-		.owner	= THIS_MODULE,
 		.pm	= &exynos_rng_pm_ops,
+		.of_match_table = exynos_rng_dt_match,
 	},
 	.probe		= exynos_rng_probe,
-	.remove		= exynos_rng_remove,
 };
 
 module_platform_driver(exynos_rng_driver);