1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
|
/*
* drivers/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 Yrjölä <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 <linux/delay.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, int wait)
{
int data, i;
for (i = 0; i < 20; i++) {
data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
if (data || !wait)
break;
udelay(10);
}
return data;
}
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");
|
