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
|
/*
* exynos-rng.c - Random Number Generator driver for the exynos
*
* Copyright (C) 2012 Samsung Electronics
* Jonghwa Lee <jonghwa3.lee@smasung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation;
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <linux/hw_random.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/pm_runtime.h>
#include <linux/err.h>
#define EXYNOS_PRNG_STATUS_OFFSET 0x10
#define EXYNOS_PRNG_SEED_OFFSET 0x140
#define EXYNOS_PRNG_OUT1_OFFSET 0x160
#define SEED_SETTING_DONE BIT(1)
#define PRNG_START 0x18
#define PRNG_DONE BIT(5)
#define EXYNOS_AUTOSUSPEND_DELAY 100
struct exynos_rng {
struct device *dev;
struct hwrng rng;
void __iomem *mem;
struct clk *clk;
};
static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
{
return __raw_readl(rng->mem + offset);
}
static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
{
__raw_writel(val, rng->mem + offset);
}
static int exynos_init(struct hwrng *rng)
{
struct exynos_rng *exynos_rng = container_of(rng,
struct exynos_rng, rng);
int i;
int ret = 0;
pm_runtime_get_sync(exynos_rng->dev);
for (i = 0 ; i < 5 ; i++)
exynos_rng_writel(exynos_rng, jiffies,
EXYNOS_PRNG_SEED_OFFSET + 4*i);
if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
& SEED_SETTING_DONE))
ret = -EIO;
pm_runtime_put_noidle(exynos_rng->dev);
return ret;
}
static int exynos_read(struct hwrng *rng, void *buf,
size_t max, bool wait)
{
struct exynos_rng *exynos_rng = container_of(rng,
struct exynos_rng, rng);
u32 *data = buf;
pm_runtime_get_sync(exynos_rng->dev);
exynos_rng_writel(exynos_rng, PRNG_START, 0);
while (!(exynos_rng_readl(exynos_rng,
EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
cpu_relax();
exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
pm_runtime_mark_last_busy(exynos_rng->dev);
pm_runtime_autosuspend(exynos_rng->dev);
return 4;
}
static int exynos_rng_probe(struct platform_device *pdev)
{
struct exynos_rng *exynos_rng;
struct resource *res;
exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng),
GFP_KERNEL);
if (!exynos_rng)
return -ENOMEM;
exynos_rng->dev = &pdev->dev;
exynos_rng->rng.name = "exynos";
exynos_rng->rng.init = exynos_init;
exynos_rng->rng.read = exynos_read;
exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
if (IS_ERR(exynos_rng->clk)) {
dev_err(&pdev->dev, "Couldn't get clock.\n");
return -ENOENT;
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(exynos_rng->mem))
return PTR_ERR(exynos_rng->mem);
platform_set_drvdata(pdev, exynos_rng);
pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
pm_runtime_use_autosuspend(&pdev->dev);
pm_runtime_enable(&pdev->dev);
return hwrng_register(&exynos_rng->rng);
}
static int exynos_rng_remove(struct platform_device *pdev)
{
struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
hwrng_unregister(&exynos_rng->rng);
return 0;
}
static int exynos_rng_runtime_suspend(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
clk_disable_unprepare(exynos_rng->clk);
return 0;
}
static int exynos_rng_runtime_resume(struct device *dev)
{
struct platform_device *pdev = to_platform_device(dev);
struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
return clk_prepare_enable(exynos_rng->clk);
}
static UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
exynos_rng_runtime_resume, NULL);
static struct platform_driver exynos_rng_driver = {
.driver = {
.name = "exynos-rng",
.owner = THIS_MODULE,
.pm = &exynos_rng_pm_ops,
},
.probe = exynos_rng_probe,
.remove = exynos_rng_remove,
};
module_platform_driver(exynos_rng_driver);
MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
MODULE_LICENSE("GPL");
|
