Initial import

1 files changed, 172 insertions, 0 deletions

diff --git a/drivers/char/hw_random/exynos-rng.c b/drivers/char/hw_random/exynos-rng.c
new file mode 100644
index 000000000..dc4701fd8
--- /dev/null
+++ b/drivers/char/hw_random/exynos-rng.c
@@ -0,0 +1,172 @@
+/*
+ * exynos-rng.c - Random Number Generator driver for the exynos
+ *
+ * Copyright (C) 2012 Samsung Electronics
+ * Jonghwa Lee <jonghwa3.lee@smasung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/hw_random.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include <linux/pm_runtime.h>
+#include <linux/err.h>
+
+#define EXYNOS_PRNG_STATUS_OFFSET	0x10
+#define EXYNOS_PRNG_SEED_OFFSET		0x140
+#define EXYNOS_PRNG_OUT1_OFFSET		0x160
+#define SEED_SETTING_DONE		BIT(1)
+#define PRNG_START			0x18
+#define PRNG_DONE			BIT(5)
+#define EXYNOS_AUTOSUSPEND_DELAY	100
+
+struct exynos_rng {
+	struct device *dev;
+	struct hwrng rng;
+	void __iomem *mem;
+	struct clk *clk;
+};
+
+static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
+{
+	return	__raw_readl(rng->mem + offset);
+}
+
+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)
+{
+	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);
+
+	if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
+						 & SEED_SETTING_DONE))
+		ret = -EIO;
+
+	pm_runtime_put_noidle(exynos_rng->dev);
+
+	return ret;
+}
+
+static int exynos_read(struct hwrng *rng, void *buf,
+					size_t max, bool wait)
+{
+	struct exynos_rng *exynos_rng = container_of(rng,
+						struct exynos_rng, rng);
+	u32 *data = buf;
+
+	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))
+		cpu_relax();
+
+	exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
+
+	*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
+
+	pm_runtime_mark_last_busy(exynos_rng->dev);
+	pm_runtime_autosuspend(exynos_rng->dev);
+
+	return 4;
+}
+
+static int exynos_rng_probe(struct platform_device *pdev)
+{
+	struct exynos_rng *exynos_rng;
+	struct resource *res;
+
+	exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng),
+					GFP_KERNEL);
+	if (!exynos_rng)
+		return -ENOMEM;
+
+	exynos_rng->dev = &pdev->dev;
+	exynos_rng->rng.name = "exynos";
+	exynos_rng->rng.init =	exynos_init;
+	exynos_rng->rng.read = exynos_read;
+	exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
+	if (IS_ERR(exynos_rng->clk)) {
+		dev_err(&pdev->dev, "Couldn't get clock.\n");
+		return -ENOENT;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(exynos_rng->mem))
+		return PTR_ERR(exynos_rng->mem);
+
+	platform_set_drvdata(pdev, exynos_rng);
+
+	pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	return devm_hwrng_register(&pdev->dev, &exynos_rng->rng);
+}
+
+#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);
+
+	clk_disable_unprepare(exynos_rng->clk);
+
+	return 0;
+}
+
+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);
+
+	return clk_prepare_enable(exynos_rng->clk);
+}
+#endif
+
+static UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
+					exynos_rng_runtime_resume, NULL);
+
+static struct platform_driver exynos_rng_driver = {
+	.driver		= {
+		.name	= "exynos-rng",
+		.pm	= &exynos_rng_pm_ops,
+	},
+	.probe		= exynos_rng_probe,
+};
+
+module_platform_driver(exynos_rng_driver);
+
+MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
+MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
+MODULE_LICENSE("GPL");