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
|
/*
* omap3-rom-rng.c - RNG driver for TI OMAP3 CPU family
*
* Copyright (C) 2009 Nokia Corporation
* Author: Juha Yrjola <juha.yrjola@solidboot.com>
*
* Copyright (C) 2013 Pali Rohár <pali.rohar@gmail.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.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/hw_random.h>
#include <linux/workqueue.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#define RNG_RESET 0x01
#define RNG_GEN_PRNG_HW_INIT 0x02
#define RNG_GEN_HW 0x08
/* param1: ptr, param2: count, param3: flag */
static u32 (*omap3_rom_rng_call)(u32, u32, u32);
static struct delayed_work idle_work;
static int rng_idle;
static struct clk *rng_clk;
static void omap3_rom_rng_idle(struct work_struct *work)
{
int r;
r = omap3_rom_rng_call(0, 0, RNG_RESET);
if (r != 0) {
pr_err("reset failed: %d\n", r);
return;
}
clk_disable_unprepare(rng_clk);
rng_idle = 1;
}
static int omap3_rom_rng_get_random(void *buf, unsigned int count)
{
u32 r;
u32 ptr;
cancel_delayed_work_sync(&idle_work);
if (rng_idle) {
clk_prepare_enable(rng_clk);
r = omap3_rom_rng_call(0, 0, RNG_GEN_PRNG_HW_INIT);
if (r != 0) {
clk_disable_unprepare(rng_clk);
pr_err("HW init failed: %d\n", r);
return -EIO;
}
rng_idle = 0;
}
ptr = virt_to_phys(buf);
r = omap3_rom_rng_call(ptr, count, RNG_GEN_HW);
schedule_delayed_work(&idle_work, msecs_to_jiffies(500));
if (r != 0)
return -EINVAL;
return 0;
}
static int omap3_rom_rng_read(struct hwrng *rng, void *data, size_t max, bool w)
{
int r;
r = omap3_rom_rng_get_random(data, 4);
if (r < 0)
return r;
return 4;
}
static struct hwrng omap3_rom_rng_ops = {
.name = "omap3-rom",
.read = omap3_rom_rng_read,
};
static int omap3_rom_rng_probe(struct platform_device *pdev)
{
pr_info("initializing\n");
omap3_rom_rng_call = pdev->dev.platform_data;
if (!omap3_rom_rng_call) {
pr_err("omap3_rom_rng_call is NULL\n");
return -EINVAL;
}
INIT_DELAYED_WORK(&idle_work, omap3_rom_rng_idle);
rng_clk = devm_clk_get(&pdev->dev, "ick");
if (IS_ERR(rng_clk)) {
pr_err("unable to get RNG clock\n");
return PTR_ERR(rng_clk);
}
/* Leave the RNG in reset state. */
clk_prepare_enable(rng_clk);
omap3_rom_rng_idle(0);
return hwrng_register(&omap3_rom_rng_ops);
}
static int omap3_rom_rng_remove(struct platform_device *pdev)
{
cancel_delayed_work_sync(&idle_work);
hwrng_unregister(&omap3_rom_rng_ops);
clk_disable_unprepare(rng_clk);
return 0;
}
static struct platform_driver omap3_rom_rng_driver = {
.driver = {
.name = "omap3-rom-rng",
},
.probe = omap3_rom_rng_probe,
.remove = omap3_rom_rng_remove,
};
module_platform_driver(omap3_rom_rng_driver);
MODULE_ALIAS("platform:omap3-rom-rng");
MODULE_AUTHOR("Juha Yrjola");
MODULE_AUTHOR("Pali Rohár <pali.rohar@gmail.com>");
MODULE_LICENSE("GPL");
|
