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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /drivers/char/hw_random/atmel-rng.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'drivers/char/hw_random/atmel-rng.c')
-rw-r--r--drivers/char/hw_random/atmel-rng.c148
1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/char/hw_random/atmel-rng.c b/drivers/char/hw_random/atmel-rng.c
new file mode 100644
index 00000000000..f518b99f53f
--- /dev/null
+++ b/drivers/char/hw_random/atmel-rng.c
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2011 Peter Korsgaard <jacmet@sunsite.dk>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/hw_random.h>
+#include <linux/platform_device.h>
+
+#define TRNG_CR 0x00
+#define TRNG_ISR 0x1c
+#define TRNG_ODATA 0x50
+
+#define TRNG_KEY 0x524e4700 /* RNG */
+
+struct atmel_trng {
+ struct clk *clk;
+ void __iomem *base;
+ struct hwrng rng;
+};
+
+static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max,
+ bool wait)
+{
+ struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng);
+ u32 *data = buf;
+
+ /* data ready? */
+ if (readl(trng->base + TRNG_ODATA) & 1) {
+ *data = readl(trng->base + TRNG_ODATA);
+ return 4;
+ } else
+ return 0;
+}
+
+static int atmel_trng_probe(struct platform_device *pdev)
+{
+ struct atmel_trng *trng;
+ struct resource *res;
+ int ret;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -EINVAL;
+
+ trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
+ if (!trng)
+ return -ENOMEM;
+
+ if (!devm_request_mem_region(&pdev->dev, res->start,
+ resource_size(res), pdev->name))
+ return -EBUSY;
+
+ trng->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+ if (!trng->base)
+ return -EBUSY;
+
+ trng->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(trng->clk))
+ return PTR_ERR(trng->clk);
+
+ ret = clk_enable(trng->clk);
+ if (ret)
+ goto err_enable;
+
+ writel(TRNG_KEY | 1, trng->base + TRNG_CR);
+ trng->rng.name = pdev->name;
+ trng->rng.read = atmel_trng_read;
+
+ ret = hwrng_register(&trng->rng);
+ if (ret)
+ goto err_register;
+
+ platform_set_drvdata(pdev, trng);
+
+ return 0;
+
+err_register:
+ clk_disable(trng->clk);
+err_enable:
+ clk_put(trng->clk);
+
+ return ret;
+}
+
+static int __devexit atmel_trng_remove(struct platform_device *pdev)
+{
+ struct atmel_trng *trng = platform_get_drvdata(pdev);
+
+ hwrng_unregister(&trng->rng);
+
+ writel(TRNG_KEY, trng->base + TRNG_CR);
+ clk_disable(trng->clk);
+ clk_put(trng->clk);
+
+ platform_set_drvdata(pdev, NULL);
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+static int atmel_trng_suspend(struct device *dev)
+{
+ struct atmel_trng *trng = dev_get_drvdata(dev);
+
+ clk_disable(trng->clk);
+
+ return 0;
+}
+
+static int atmel_trng_resume(struct device *dev)
+{
+ struct atmel_trng *trng = dev_get_drvdata(dev);
+
+ return clk_enable(trng->clk);
+}
+
+static const struct dev_pm_ops atmel_trng_pm_ops = {
+ .suspend = atmel_trng_suspend,
+ .resume = atmel_trng_resume,
+};
+#endif /* CONFIG_PM */
+
+static struct platform_driver atmel_trng_driver = {
+ .probe = atmel_trng_probe,
+ .remove = __devexit_p(atmel_trng_remove),
+ .driver = {
+ .name = "atmel-trng",
+ .owner = THIS_MODULE,
+#ifdef CONFIG_PM
+ .pm = &atmel_trng_pm_ops,
+#endif /* CONFIG_PM */
+ },
+};
+
+module_platform_driver(atmel_trng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
+MODULE_DESCRIPTION("Atmel true random number generator driver");