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authorPali Rohár <pali.rohar@gmail.com>2013-09-20 15:25:06 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2013-10-16 20:56:24 +0800
commit1c6b7c2108bdb0c6a17044830028a649dbaca913 (patch)
treeb65b8f21fcc13c8f6674bf80d589f29d07426b72 /drivers/char
parent16c0c4e1656c14ef9deac189a4240b5ca19c6919 (diff)
downloadlinux-linaro-stable-1c6b7c2108bdb0c6a17044830028a649dbaca913.tar.gz
hwrng: OMAP3 ROM Random Number Generator support
This driver provides kernel-side support for the Random Number Generator hardware found on OMAP34xx processors. This driver comes from Maemo 2.6.28 kernel and was tested on Nokia RX-51. It is platform device because it needs board specific function for smc calls. Signed-off-by: Pali Rohár <pali.rohar@gmail.com> Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com> Acked-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/hw_random/Kconfig13
-rw-r--r--drivers/char/hw_random/Makefile1
-rw-r--r--drivers/char/hw_random/omap3-rom-rng.c141
3 files changed, 155 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 0aa9d91daef5..0a331c341fff 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -165,6 +165,19 @@ config HW_RANDOM_OMAP
If unsure, say Y.
+config HW_RANDOM_OMAP3_ROM
+ tristate "OMAP3 ROM Random Number Generator support"
+ depends on HW_RANDOM && ARCH_OMAP3
+ default HW_RANDOM
+ ---help---
+ This driver provides kernel-side support for the Random Number
+ Generator hardware found on OMAP34xx processors.
+
+ To compile this driver as a module, choose M here: the
+ module will be called omap3-rom-rng.
+
+ If unsure, say Y.
+
config HW_RANDOM_OCTEON
tristate "Octeon Random Number Generator support"
depends on HW_RANDOM && CAVIUM_OCTEON_SOC
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index bed467c9300e..7c8aa8077f5e 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -15,6 +15,7 @@ n2-rng-y := n2-drv.o n2-asm.o
obj-$(CONFIG_HW_RANDOM_VIA) += via-rng.o
obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
+obj-$(CONFIG_HW_RANDOM_OMAP3_ROM) += omap3-rom-rng.o
obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o
diff --git a/drivers/char/hw_random/omap3-rom-rng.c b/drivers/char/hw_random/omap3-rom-rng.c
new file mode 100644
index 000000000000..c853e9e68573
--- /dev/null
+++ b/drivers/char/hw_random/omap3-rom-rng.c
@@ -0,0 +1,141 @@
+/*
+ * omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family
+ *
+ * Copyright (C) 2009 Nokia Corporation
+ * Author: Juha Yrjola <juha.yrjola@solidboot.com>
+ *
+ * Copyright (C) 2013 Pali Rohár <pali.rohar@gmail.com>
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/hw_random.h>
+#include <linux/timer.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+
+#define RNG_RESET 0x01
+#define RNG_GEN_PRNG_HW_INIT 0x02
+#define RNG_GEN_HW 0x08
+
+/* param1: ptr, param2: count, param3: flag */
+static u32 (*omap3_rom_rng_call)(u32, u32, u32);
+
+static struct timer_list idle_timer;
+static int rng_idle;
+static struct clk *rng_clk;
+
+static void omap3_rom_rng_idle(unsigned long data)
+{
+ int r;
+
+ r = omap3_rom_rng_call(0, 0, RNG_RESET);
+ if (r != 0) {
+ pr_err("reset failed: %d\n", r);
+ return;
+ }
+ clk_disable_unprepare(rng_clk);
+ rng_idle = 1;
+}
+
+static int omap3_rom_rng_get_random(void *buf, unsigned int count)
+{
+ u32 r;
+ u32 ptr;
+
+ del_timer_sync(&idle_timer);
+ if (rng_idle) {
+ clk_prepare_enable(rng_clk);
+ r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
+ if (r != 0) {
+ clk_disable_unprepare(rng_clk);
+ pr_err("HW init failed: %d\n", r);
+ return -EIO;
+ }
+ rng_idle = 0;
+ }
+
+ ptr = virt_to_phys(buf);
+ r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
+ mod_timer(&idle_timer, jiffies + msecs_to_jiffies(500));
+ if (r != 0)
+ return -EINVAL;
+ return 0;
+}
+
+static int omap3_rom_rng_data_present(struct hwrng *rng, int wait)
+{
+ return 1;
+}
+
+static int omap3_rom_rng_data_read(struct hwrng *rng, u32 *data)
+{
+ int r;
+
+ r = omap3_rom_rng_get_random(data, 4);
+ if (r < 0)
+ return r;
+ return 4;
+}
+
+static struct hwrng omap3_rom_rng_ops = {
+ .name = "omap3-rom",
+ .data_present = omap3_rom_rng_data_present,
+ .data_read = omap3_rom_rng_data_read,
+};
+
+static int omap3_rom_rng_probe(struct platform_device *pdev)
+{
+ pr_info("initializing\n");
+
+ omap3_rom_rng_call = pdev->dev.platform_data;
+ if (!omap3_rom_rng_call) {
+ pr_err("omap3_rom_rng_call is NULL\n");
+ return -EINVAL;
+ }
+
+ setup_timer(&idle_timer, omap3_rom_rng_idle, 0);
+ rng_clk = clk_get(&pdev->dev, "ick");
+ if (IS_ERR(rng_clk)) {
+ pr_err("unable to get RNG clock\n");
+ return PTR_ERR(rng_clk);
+ }
+
+ /* Leave the RNG in reset state. */
+ clk_prepare_enable(rng_clk);
+ omap3_rom_rng_idle(0);
+
+ return hwrng_register(&omap3_rom_rng_ops);
+}
+
+static int omap3_rom_rng_remove(struct platform_device *pdev)
+{
+ hwrng_unregister(&omap3_rom_rng_ops);
+ clk_disable_unprepare(rng_clk);
+ clk_put(rng_clk);
+ return 0;
+}
+
+static struct platform_driver omap3_rom_rng_driver = {
+ .driver = {
+ .name = "omap3-rom-rng",
+ .owner = THIS_MODULE,
+ },
+ .probe = omap3_rom_rng_probe,
+ .remove = omap3_rom_rng_remove,
+};
+
+module_platform_driver(omap3_rom_rng_driver);
+
+MODULE_ALIAS("platform:omap3-rom-rng");
+MODULE_AUTHOR("Juha Yrjola");
+MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
+MODULE_LICENSE("GPL");