3 files changed, 195 insertions, 0 deletions

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index f45dad39a18b..b01d67328243 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -263,3 +263,15 @@ config HW_RANDOM_PSERIES
           module will be called pseries-rng.
 
           If unsure, say Y.
+
+config HW_RANDOM_EXYNOS
+        tristate "EXYNOS HW random number generator support"
+        depends on HW_RANDOM && HAS_IOMEM && HAVE_CLK
+        ---help---
+          This driver provides kernel-side support for the Random Number
+          Generator hardware found on EXYNOS SOCs.
+
+          To compile this driver as a module, choose M here: the
+          module will be called exynos-rng.
+
+          If unsure, say Y.
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index d901dfa30321..8d6d173b65e6 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -23,3 +23,4 @@ obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
 obj-$(CONFIG_HW_RANDOM_PICOXCELL) += picoxcell-rng.o
 obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
 obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
+obj-$(CONFIG_HW_RANDOM_EXYNOS)  += exynos-rng.o
diff --git a/drivers/char/hw_random/exynos-rng.c b/drivers/char/hw_random/exynos-rng.c
new file mode 100644
index 000000000000..232ba9ce579c
--- /dev/null
+++ b/drivers/char/hw_random/exynos-rng.c
@@ -0,0 +1,182 @@
+/*
+ * 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/init.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 __devinit exynos_rng_probe(struct platform_device *pdev)
+{
+        struct exynos_rng *exynos_rng;
+
+        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;
+        }
+
+        exynos_rng->mem = devm_request_and_ioremap(&pdev->dev,
+                        platform_get_resource(pdev, IORESOURCE_MEM, 0));
+        if (!exynos_rng->mem)
+                return -EBUSY;
+
+        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 hwrng_register(&exynos_rng->rng);
+}
+
+static int __devexit exynos_rng_remove(struct platform_device *pdev)
+{
+        struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
+
+        hwrng_unregister(&exynos_rng->rng);
+
+        return 0;
+}
+
+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);
+}
+
+
+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",
+                .owner  = THIS_MODULE,
+                .pm     = &exynos_rng_pm_ops,
+        },
+        .probe          = exynos_rng_probe,
+        .remove         = __devexit_p(exynos_rng_remove),
+};
+
+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");