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authorLubomir Rintel <lkundrak@v3.sk>2013-03-28 07:19:38 +0100
committerHerbert Xu <herbert@gondor.apana.org.au>2013-04-25 21:01:44 +0800
commit8c4196a2fd7c31acd6d02d9921f7896b8f160c92 (patch)
tree8319de82961c9a0aeac2cc7c9f7e955b6d706992 /drivers/char
parent96aef9a8ba37da48f2ae9612ccd0f6b7bc0542eb (diff)
downloadvexpress-lsk-8c4196a2fd7c31acd6d02d9921f7896b8f160c92.tar.gz
hwrng: bcm2835 - Add Broadcom BCM2835 RNG driver
This adds a driver for random number generator present on Broadcom BCM2835 SoC, used in Raspberry Pi and Roku 2 devices. Signed-off-by: Dom Cobley <popcornmix@gmail.com> Signed-off-by: Lubomir Rintel <lkundrak@v3.sk> Tested-by: Stephen Warren <swarren@wwwdotorg.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Matt Mackall <mpm@selenic.com> Cc: linux-rpi-kernel@lists.infradead.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/hw_random/Kconfig12
-rw-r--r--drivers/char/hw_random/Makefile1
-rw-r--r--drivers/char/hw_random/bcm2835-rng.c113
3 files changed, 126 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index c5a0262251b..2f9dbf7568f 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -86,6 +86,18 @@ config HW_RANDOM_BCM63XX
If unusure, say Y.
+config HW_RANDOM_BCM2835
+ tristate "Broadcom BCM2835 Random Number Generator support"
+ depends on HW_RANDOM && ARCH_BCM2835
+ default HW_RANDOM
+ ---help---
+ This driver provides kernel-side support for the Random Number
+ Generator hardware found on the Broadcom BCM2835 SoCs.
+
+ To compile this driver as a module, choose M here: the
+ module will be called bcm2835-rng
+
+ If unsure, say Y.
config HW_RANDOM_GEODE
tristate "AMD Geode HW Random Number Generator support"
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 1fd7eec9fbf..bed467c9300 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -26,3 +26,4 @@ obj-$(CONFIG_HW_RANDOM_PPC4XX) += ppc4xx-rng.o
obj-$(CONFIG_HW_RANDOM_PSERIES) += pseries-rng.o
obj-$(CONFIG_HW_RANDOM_EXYNOS) += exynos-rng.o
obj-$(CONFIG_HW_RANDOM_TPM) += tpm-rng.o
+obj-$(CONFIG_HW_RANDOM_BCM2835) += bcm2835-rng.o
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
new file mode 100644
index 00000000000..eb7f14725eb
--- /dev/null
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -0,0 +1,113 @@
+/**
+ * Copyright (c) 2010-2012 Broadcom. All rights reserved.
+ * Copyright (c) 2013 Lubomir Rintel
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License ("GPL")
+ * version 2, as published by the Free Software Foundation.
+ */
+
+#include <linux/hw_random.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/printk.h>
+
+#define RNG_CTRL 0x0
+#define RNG_STATUS 0x4
+#define RNG_DATA 0x8
+
+/* enable rng */
+#define RNG_RBGEN 0x1
+
+/* the initial numbers generated are "less random" so will be discarded */
+#define RNG_WARMUP_COUNT 0x40000
+
+static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
+ bool wait)
+{
+ void __iomem *rng_base = (void __iomem *)rng->priv;
+
+ while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) {
+ if (!wait)
+ return 0;
+ cpu_relax();
+ }
+
+ *(u32 *)buf = __raw_readl(rng_base + RNG_DATA);
+ return sizeof(u32);
+}
+
+static struct hwrng bcm2835_rng_ops = {
+ .name = "bcm2835",
+ .read = bcm2835_rng_read,
+};
+
+static int bcm2835_rng_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct device_node *np = dev->of_node;
+ void __iomem *rng_base;
+ int err;
+
+ /* map peripheral */
+ rng_base = of_iomap(np, 0);
+ if (!rng_base) {
+ dev_err(dev, "failed to remap rng regs");
+ return -ENODEV;
+ }
+ bcm2835_rng_ops.priv = (unsigned long)rng_base;
+
+ /* register driver */
+ err = hwrng_register(&bcm2835_rng_ops);
+ if (err) {
+ dev_err(dev, "hwrng registration failed\n");
+ iounmap(rng_base);
+ } else {
+ dev_info(dev, "hwrng registered\n");
+
+ /* set warm-up count & enable */
+ __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
+ __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
+ }
+ return err;
+}
+
+static int bcm2835_rng_remove(struct platform_device *pdev)
+{
+ void __iomem *rng_base = (void __iomem *)bcm2835_rng_ops.priv;
+
+ /* disable rng hardware */
+ __raw_writel(0, rng_base + RNG_CTRL);
+
+ /* unregister driver */
+ hwrng_unregister(&bcm2835_rng_ops);
+ iounmap(rng_base);
+
+ return 0;
+}
+
+static const struct of_device_id bcm2835_rng_of_match[] = {
+ { .compatible = "brcm,bcm2835-rng", },
+ {},
+};
+MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);
+
+static struct platform_driver bcm2835_rng_driver = {
+ .driver = {
+ .name = "bcm2835-rng",
+ .owner = THIS_MODULE,
+ .of_match_table = bcm2835_rng_of_match,
+ },
+ .probe = bcm2835_rng_probe,
+ .remove = bcm2835_rng_remove,
+};
+module_platform_driver(bcm2835_rng_driver);
+
+MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
+MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
+MODULE_LICENSE("GPLv2");