2 * driver/char/hw_random/omap-rng.c
4 * RNG driver for TI OMAP CPU family
6 * Author: Deepak Saxena <dsaxena@plexity.net>
8 * Copyright 2005 (c) MontaVista Software, Inc.
10 * Mostly based on original driver:
12 * Copyright (C) 2005 Nokia Corporation
13 * Author: Juha Yrj��<juha.yrjola@nokia.com>
15 * This file is licensed under the terms of the GNU General Public
16 * License version 2. This program is licensed "as is" without any
17 * warranty of any kind, whether express or implied.
21 * - Make status updated be interrupt driven so we don't poll
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/random.h>
28 #include <linux/err.h>
29 #include <linux/device.h>
30 #include <linux/hw_random.h>
33 #include <asm/hardware/clock.h>
35 #define RNG_OUT_REG 0x00 /* Output register */
36 #define RNG_STAT_REG 0x04 /* Status register
38 #define RNG_ALARM_REG 0x24 /* Alarm register
39 [7:0] = ALARM_COUNTER */
40 #define RNG_CONFIG_REG 0x28 /* Configuration register
43 [2:0] = RING1_DELAY */
44 #define RNG_REV_REG 0x3c /* Revision register
46 #define RNG_MASK_REG 0x40 /* Mask and reset register
50 #define RNG_SYSSTATUS 0x44 /* System status
53 static void __iomem *rng_base;
54 static struct clk *rng_ick;
55 static struct device *rng_dev;
57 static u32 omap_rng_read_reg(int reg)
59 return __raw_readl(rng_base + reg);
62 static void omap_rng_write_reg(int reg, u32 val)
64 __raw_writel(val, rng_base + reg);
67 /* REVISIT: Does the status bit really work on 16xx? */
68 static int omap_rng_data_present(struct hwrng *rng)
70 return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
73 static int omap_rng_data_read(struct hwrng *rng, u32 *data)
75 *data = omap_rng_read_reg(RNG_OUT_REG);
80 static struct hwrng omap_rng_ops = {
82 .data_present = omap_rng_data_present,
83 .data_read = omap_rng_data_read,
86 static int __init omap_rng_probe(struct device *dev)
88 struct platform_device *pdev = to_platform_device(dev);
89 struct resource *res, *mem;
93 * A bit ugly, and it will never actually happen but there can
94 * be only one RNG and this catches any bork
98 if (cpu_is_omap24xx()) {
99 rng_ick = clk_get(NULL, "rng_ick");
100 if (IS_ERR(rng_ick)) {
101 dev_err(dev, "Could not get rng_ick\n");
102 ret = PTR_ERR(rng_ick);
110 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
115 mem = request_mem_region(res->start, res->end - res->start + 1,
120 dev_set_drvdata(dev, mem);
121 rng_base = (u32 __iomem *)io_p2v(res->start);
123 ret = hwrng_register(&omap_rng_ops);
125 release_resource(mem);
130 dev_info(dev, "OMAP Random Number Generator ver. %02x\n",
131 omap_rng_read_reg(RNG_REV_REG));
132 omap_rng_write_reg(RNG_MASK_REG, 0x1);
139 static int __exit omap_rng_remove(struct device *dev)
141 struct resource *mem = dev_get_drvdata(dev);
143 hwrng_unregister(&omap_rng_ops);
145 omap_rng_write_reg(RNG_MASK_REG, 0x0);
147 if (cpu_is_omap24xx()) {
152 release_resource(mem);
160 static int omap_rng_suspend(struct device *dev, pm_message_t message, u32 level)
162 omap_rng_write_reg(RNG_MASK_REG, 0x0);
167 static int omap_rng_resume(struct device *dev, pm_message_t message, u32 level)
169 omap_rng_write_reg(RNG_MASK_REG, 0x1);
176 #define omap_rng_suspend NULL
177 #define omap_rng_resume NULL
182 static struct device_driver omap_rng_driver = {
184 .bus = &platform_bus_type,
185 .probe = omap_rng_probe,
186 .remove = __exit_p(omap_rng_remove),
187 .suspend = omap_rng_suspend,
188 .resume = omap_rng_resume
191 static int __init omap_rng_init(void)
193 if (!cpu_is_omap16xx() && !cpu_is_omap24xx())
196 return driver_register(&omap_rng_driver);
199 static void __exit omap_rng_exit(void)
201 driver_unregister(&omap_rng_driver);
204 module_init(omap_rng_init);
205 module_exit(omap_rng_exit);
207 MODULE_AUTHOR("Deepak Saxena (and others)");
208 MODULE_LICENSE("GPL");