--- /dev/null
+/*
+ * 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/clk.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+
+#include <asm/io.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 platform_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 platform_device *pdev)
+{
+ 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(&pdev->dev, "Could not get rng_ick\n");
+ ret = PTR_ERR(rng_ick);
+ return ret;
+ } else
+ clk_enable(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(&pdev->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(&pdev->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 = pdev;
+
+ return 0;
+}
+
+static int __exit omap_rng_remove(struct platform_device *pdev)
+{
+ struct resource *mem = dev_get_drvdata(&pdev->dev);
+
+ hwrng_unregister(&omap_rng_ops);
+
+ omap_rng_write_reg(RNG_MASK_REG, 0x0);
+
+ if (cpu_is_omap24xx()) {
+ clk_disable(rng_ick);
+ clk_put(rng_ick);
+ }
+
+ release_resource(mem);
+ rng_base = NULL;
+
+ return 0;
+}
+
+#ifdef CONFIG_PM
+
+static int omap_rng_suspend(struct platform_device *pdev, pm_message_t message)
+{
+ omap_rng_write_reg(RNG_MASK_REG, 0x0);
+ return 0;
+}
+
+static int omap_rng_resume(struct platform_device *pdev)
+{
+ omap_rng_write_reg(RNG_MASK_REG, 0x1);
+ return 0;
+}
+
+#else
+
+#define omap_rng_suspend NULL
+#define omap_rng_resume NULL
+
+#endif
+
+
+static struct platform_driver omap_rng_driver = {
+ .driver = {
+ .name = "omap_rng",
+ .owner = THIS_MODULE,
+ },
+ .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 platform_driver_register(&omap_rng_driver);
+}
+
+static void __exit omap_rng_exit(void)
+{
+ platform_driver_unregister(&omap_rng_driver);
+}
+
+module_init(omap_rng_init);
+module_exit(omap_rng_exit);
+
+MODULE_AUTHOR("Deepak Saxena (and others)");
+MODULE_LICENSE("GPL");
git://git.onelab.eu / linux-2.6.git / blobdiff