[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>

1 files changed, 208 insertions, 0 deletions

diff --git a/drivers/char/hw_random/omap-rng.c b/drivers/char/hw_random/omap-rng.c
new file mode 100644
index 000000000000..819516b35a79
--- /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");