ARM: 7409/1: Do not call flush_cache_user_range with mmap_sem held
[linux/fpc-iii.git] / drivers / char / hw_random / omap-rng.c
blob2cc755a64302b479e75e7526a460a2dccff1f3a4
1 /*
2 * omap-rng.c - RNG driver for TI OMAP CPU family
4 * Author: Deepak Saxena <dsaxena@plexity.net>
6 * Copyright 2005 (c) MontaVista Software, Inc.
8 * Mostly based on original driver:
10 * Copyright (C) 2005 Nokia Corporation
11 * Author: Juha Yrjölä <juha.yrjola@nokia.com>
13 * This file is licensed under the terms of the GNU General Public
14 * License version 2. This program is licensed "as is" without any
15 * warranty of any kind, whether express or implied.
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/random.h>
21 #include <linux/clk.h>
22 #include <linux/err.h>
23 #include <linux/platform_device.h>
24 #include <linux/hw_random.h>
25 #include <linux/delay.h>
27 #include <asm/io.h>
29 #define RNG_OUT_REG 0x00 /* Output register */
30 #define RNG_STAT_REG 0x04 /* Status register
31 [0] = STAT_BUSY */
32 #define RNG_ALARM_REG 0x24 /* Alarm register
33 [7:0] = ALARM_COUNTER */
34 #define RNG_CONFIG_REG 0x28 /* Configuration register
35 [11:6] = RESET_COUNT
36 [5:3] = RING2_DELAY
37 [2:0] = RING1_DELAY */
38 #define RNG_REV_REG 0x3c /* Revision register
39 [7:0] = REV_NB */
40 #define RNG_MASK_REG 0x40 /* Mask and reset register
41 [2] = IT_EN
42 [1] = SOFTRESET
43 [0] = AUTOIDLE */
44 #define RNG_SYSSTATUS 0x44 /* System status
45 [0] = RESETDONE */
47 static void __iomem *rng_base;
48 static struct clk *rng_ick;
49 static struct platform_device *rng_dev;
51 static inline u32 omap_rng_read_reg(int reg)
53 return __raw_readl(rng_base + reg);
56 static inline void omap_rng_write_reg(int reg, u32 val)
58 __raw_writel(val, rng_base + reg);
61 static int omap_rng_data_present(struct hwrng *rng, int wait)
63 int data, i;
65 for (i = 0; i < 20; i++) {
66 data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
67 if (data || !wait)
68 break;
69 /* RNG produces data fast enough (2+ MBit/sec, even
70 * during "rngtest" loads, that these delays don't
71 * seem to trigger. We *could* use the RNG IRQ, but
72 * that'd be higher overhead ... so why bother?
74 udelay(10);
76 return data;
79 static int omap_rng_data_read(struct hwrng *rng, u32 *data)
81 *data = omap_rng_read_reg(RNG_OUT_REG);
83 return 4;
86 static struct hwrng omap_rng_ops = {
87 .name = "omap",
88 .data_present = omap_rng_data_present,
89 .data_read = omap_rng_data_read,
92 static int __devinit omap_rng_probe(struct platform_device *pdev)
94 struct resource *res;
95 int ret;
98 * A bit ugly, and it will never actually happen but there can
99 * be only one RNG and this catches any bork
101 if (rng_dev)
102 return -EBUSY;
104 if (cpu_is_omap24xx()) {
105 rng_ick = clk_get(&pdev->dev, "ick");
106 if (IS_ERR(rng_ick)) {
107 dev_err(&pdev->dev, "Could not get rng_ick\n");
108 ret = PTR_ERR(rng_ick);
109 return ret;
110 } else
111 clk_enable(rng_ick);
114 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
116 if (!res)
117 return -ENOENT;
119 if (!request_mem_region(res->start, resource_size(res), pdev->name)) {
120 ret = -EBUSY;
121 goto err_region;
124 dev_set_drvdata(&pdev->dev, res);
125 rng_base = ioremap(res->start, resource_size(res));
126 if (!rng_base) {
127 ret = -ENOMEM;
128 goto err_ioremap;
131 ret = hwrng_register(&omap_rng_ops);
132 if (ret)
133 goto err_register;
135 dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
136 omap_rng_read_reg(RNG_REV_REG));
137 omap_rng_write_reg(RNG_MASK_REG, 0x1);
139 rng_dev = pdev;
141 return 0;
143 err_register:
144 iounmap(rng_base);
145 rng_base = NULL;
146 err_ioremap:
147 release_mem_region(res->start, resource_size(res));
148 err_region:
149 if (cpu_is_omap24xx()) {
150 clk_disable(rng_ick);
151 clk_put(rng_ick);
153 return ret;
156 static int __exit omap_rng_remove(struct platform_device *pdev)
158 struct resource *res = dev_get_drvdata(&pdev->dev);
160 hwrng_unregister(&omap_rng_ops);
162 omap_rng_write_reg(RNG_MASK_REG, 0x0);
164 iounmap(rng_base);
166 if (cpu_is_omap24xx()) {
167 clk_disable(rng_ick);
168 clk_put(rng_ick);
171 release_mem_region(res->start, resource_size(res));
172 rng_base = NULL;
174 return 0;
177 #ifdef CONFIG_PM
179 static int omap_rng_suspend(struct platform_device *pdev, pm_message_t message)
181 omap_rng_write_reg(RNG_MASK_REG, 0x0);
182 return 0;
185 static int omap_rng_resume(struct platform_device *pdev)
187 omap_rng_write_reg(RNG_MASK_REG, 0x1);
188 return 0;
191 #else
193 #define omap_rng_suspend NULL
194 #define omap_rng_resume NULL
196 #endif
198 /* work with hotplug and coldplug */
199 MODULE_ALIAS("platform:omap_rng");
201 static struct platform_driver omap_rng_driver = {
202 .driver = {
203 .name = "omap_rng",
204 .owner = THIS_MODULE,
206 .probe = omap_rng_probe,
207 .remove = __exit_p(omap_rng_remove),
208 .suspend = omap_rng_suspend,
209 .resume = omap_rng_resume
212 static int __init omap_rng_init(void)
214 if (!cpu_is_omap16xx() && !cpu_is_omap24xx())
215 return -ENODEV;
217 return platform_driver_register(&omap_rng_driver);
220 static void __exit omap_rng_exit(void)
222 platform_driver_unregister(&omap_rng_driver);
225 module_init(omap_rng_init);
226 module_exit(omap_rng_exit);
228 MODULE_AUTHOR("Deepak Saxena (and others)");
229 MODULE_LICENSE("GPL");