[PATCH] Add TI OMAP CPU family HW RNG driver

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 1100fd7..9f7635f 100644 (file)
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -74,3 +74,17 @@ config HW_RANDOM_IXP4XX
          module will be called ixp4xx-rng.
 
          If unsure, say Y.
+
+config HW_RANDOM_OMAP
+       tristate "OMAP Random Number Generator support"
+       depends on HW_RANDOM && (ARCH_OMAP16XX || ARCH_OMAP24XX)
+       default y
+       ---help---
+         This driver provides kernel-side support for the Random Number
+         Generator hardware found on OMAP16xx and OMAP24xx multimedia
+         processors.
+
+         To compile this driver as a module, choose M here: the
+         module will be called omap-rng.
+
+         If unsure, say Y.

diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 46076df..e263ae9 100644 (file)
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_HW_RANDOM_AMD) += amd-rng.o
 obj-$(CONFIG_HW_RANDOM_GEODE) += geode-rng.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

diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
new file mode 100644 (file)
index 0000000..819516b
--- /dev/null
+++ b/drivers/char/hw_random/omap-rng.c
@@ -0,0 +1,208 @@
+/*
+ * driver/char/hw_random/omap-rng.c
+ *
+ * RNG driver for TI OMAP CPU family
+ *
+ * Author: Deepak Saxena <dsaxena@plexity.net>
+ *
+ * Copyright 2005 (c) MontaVista Software, Inc.
+ *
+ * Mostly based on original driver:
+ *
+ * Copyright (C) 2005 Nokia Corporation
+ * Author: Juha Yrj��<juha.yrjola@nokia.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.
+ *
+ * TODO:
+ *
+ * - Make status updated be interrupt driven so we don't poll
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/random.h>
+#include <linux/err.h>
+#include <linux/device.h>
+#include <linux/hw_random.h>
+
+#include <asm/io.h>
+#include <asm/hardware/clock.h>
+
+#define RNG_OUT_REG            0x00            /* Output register */
+#define RNG_STAT_REG           0x04            /* Status register
+                                                       [0] = STAT_BUSY */
+#define RNG_ALARM_REG          0x24            /* Alarm register
+                                                       [7:0] = ALARM_COUNTER */
+#define RNG_CONFIG_REG         0x28            /* Configuration register
+                                                       [11:6] = RESET_COUNT
+                                                       [5:3]  = RING2_DELAY
+                                                       [2:0]  = RING1_DELAY */
+#define RNG_REV_REG            0x3c            /* Revision register
+                                                       [7:0] = REV_NB */
+#define RNG_MASK_REG           0x40            /* Mask and reset register
+                                                       [2] = IT_EN
+                                                       [1] = SOFTRESET
+                                                       [0] = AUTOIDLE */
+#define RNG_SYSSTATUS          0x44            /* System status
+                                                       [0] = RESETDONE */
+
+static void __iomem *rng_base;
+static struct clk *rng_ick;
+static struct device *rng_dev;
+
+static u32 omap_rng_read_reg(int reg)
+{
+       return __raw_readl(rng_base + reg);
+}
+
+static void omap_rng_write_reg(int reg, u32 val)
+{
+       __raw_writel(val, rng_base + reg);
+}
+
+/* REVISIT: Does the status bit really work on 16xx? */
+static int omap_rng_data_present(struct hwrng *rng)
+{
+       return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
+}
+
+static int omap_rng_data_read(struct hwrng *rng, u32 *data)
+{
+       *data = omap_rng_read_reg(RNG_OUT_REG);
+
+       return 4;
+}
+
+static struct hwrng omap_rng_ops = {
+       .name           = "omap",
+       .data_present   = omap_rng_data_present,
+       .data_read      = omap_rng_data_read,
+};
+
+static int __init omap_rng_probe(struct device *dev)
+{
+       struct platform_device *pdev = to_platform_device(dev);
+       struct resource *res, *mem;
+       int ret;
+
+       /*
+        * A bit ugly, and it will never actually happen but there can
+        * be only one RNG and this catches any bork
+        */
+       BUG_ON(rng_dev);
+
+       if (cpu_is_omap24xx()) {
+               rng_ick = clk_get(NULL, "rng_ick");
+               if (IS_ERR(rng_ick)) {
+                       dev_err(dev, "Could not get rng_ick\n");
+                       ret = PTR_ERR(rng_ick);
+                       return ret;
+               }
+               else {
+                       clk_use(rng_ick);
+               }
+       }
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+       if (!res)
+               return -ENOENT;
+
+       mem = request_mem_region(res->start, res->end - res->start + 1,
+                                pdev->name);
+       if (mem == NULL)
+               return -EBUSY;
+
+       dev_set_drvdata(dev, mem);
+       rng_base = (u32 __iomem *)io_p2v(res->start);
+
+       ret = hwrng_register(&omap_rng_ops);
+       if (ret) {
+               release_resource(mem);
+               rng_base = NULL;
+               return ret;
+       }
+
+       dev_info(dev, "OMAP Random Number Generator ver. %02x\n",
+               omap_rng_read_reg(RNG_REV_REG));
+       omap_rng_write_reg(RNG_MASK_REG, 0x1);
+
+       rng_dev = dev;
+
+       return 0;
+}
+
+static int __exit omap_rng_remove(struct device *dev)
+{
+       struct resource *mem = dev_get_drvdata(dev);
+
+       hwrng_unregister(&omap_rng_ops);
+
+       omap_rng_write_reg(RNG_MASK_REG, 0x0);
+
+       if (cpu_is_omap24xx()) {
+               clk_unuse(rng_ick);
+               clk_put(rng_ick);
+       }
+
+       release_resource(mem);
+       rng_base = NULL;
+
+       return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int omap_rng_suspend(struct device *dev, pm_message_t message, u32 level)
+{
+       omap_rng_write_reg(RNG_MASK_REG, 0x0);
+
+       return 0;
+}
+
+static int omap_rng_resume(struct device *dev, pm_message_t message, u32 level)
+{
+       omap_rng_write_reg(RNG_MASK_REG, 0x1);
+
+       return 1;
+}
+
+#else
+
+#define        omap_rng_suspend        NULL
+#define        omap_rng_resume         NULL
+
+#endif
+
+
+static struct device_driver omap_rng_driver = {
+       .name           = "omap_rng",
+       .bus            = &platform_bus_type,
+       .probe          = omap_rng_probe,
+       .remove         = __exit_p(omap_rng_remove),
+       .suspend        = omap_rng_suspend,
+       .resume         = omap_rng_resume
+};
+
+static int __init omap_rng_init(void)
+{
+       if (!cpu_is_omap16xx() && !cpu_is_omap24xx())
+               return -ENODEV;
+
+       return driver_register(&omap_rng_driver);
+}
+
+static void __exit omap_rng_exit(void)
+{
+       driver_unregister(&omap_rng_driver);
+}
+
+module_init(omap_rng_init);
+module_exit(omap_rng_exit);
+
+MODULE_AUTHOR("Deepak Saxena (and others)");
+MODULE_LICENSE("GPL");