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
|
/*
* Generic PowerPC 44x RNG driver
*
* Copyright 2011 IBM Corporation
*
* 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; version 2 of the License.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
#include <linux/delay.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <asm/io.h>
#define PPC4XX_TRNG_DEV_CTRL 0x60080
#define PPC4XX_TRNGE 0x00020000
#define PPC4XX_TRNG_CTRL 0x0008
#define PPC4XX_TRNG_CTRL_DALM 0x20
#define PPC4XX_TRNG_STAT 0x0004
#define PPC4XX_TRNG_STAT_B 0x1
#define PPC4XX_TRNG_DATA 0x0000
#define MODULE_NAME "ppc4xx_rng"
static int ppc4xx_rng_data_present(struct hwrng *rng, int wait)
{
void __iomem *rng_regs = (void __iomem *) rng->priv;
int busy, i, present = 0;
for (i = 0; i < 20; i++) {
busy = (in_le32(rng_regs + PPC4XX_TRNG_STAT) & PPC4XX_TRNG_STAT_B);
if (!busy || !wait) {
present = 1;
break;
}
udelay(10);
}
return present;
}
static int ppc4xx_rng_data_read(struct hwrng *rng, u32 *data)
{
void __iomem *rng_regs = (void __iomem *) rng->priv;
*data = in_le32(rng_regs + PPC4XX_TRNG_DATA);
return 4;
}
static int ppc4xx_rng_enable(int enable)
{
struct device_node *ctrl;
void __iomem *ctrl_reg;
int err = 0;
u32 val;
/* Find the main crypto device node and map it to turn the TRNG on */
ctrl = of_find_compatible_node(NULL, NULL, "amcc,ppc4xx-crypto");
if (!ctrl)
return -ENODEV;
ctrl_reg = of_iomap(ctrl, 0);
if (!ctrl_reg) {
err = -ENODEV;
goto out;
}
val = in_le32(ctrl_reg + PPC4XX_TRNG_DEV_CTRL);
if (enable)
val |= PPC4XX_TRNGE;
else
val = val & ~PPC4XX_TRNGE;
out_le32(ctrl_reg + PPC4XX_TRNG_DEV_CTRL, val);
iounmap(ctrl_reg);
out:
of_node_put(ctrl);
return err;
}
static struct hwrng ppc4xx_rng = {
.name = MODULE_NAME,
.data_present = ppc4xx_rng_data_present,
.data_read = ppc4xx_rng_data_read,
};
static int ppc4xx_rng_probe(struct platform_device *dev)
{
void __iomem *rng_regs;
int err = 0;
rng_regs = of_iomap(dev->dev.of_node, 0);
if (!rng_regs)
return -ENODEV;
err = ppc4xx_rng_enable(1);
if (err)
return err;
out_le32(rng_regs + PPC4XX_TRNG_CTRL, PPC4XX_TRNG_CTRL_DALM);
ppc4xx_rng.priv = (unsigned long) rng_regs;
err = hwrng_register(&ppc4xx_rng);
return err;
}
static int ppc4xx_rng_remove(struct platform_device *dev)
{
void __iomem *rng_regs = (void __iomem *) ppc4xx_rng.priv;
hwrng_unregister(&ppc4xx_rng);
ppc4xx_rng_enable(0);
iounmap(rng_regs);
return 0;
}
static struct of_device_id ppc4xx_rng_match[] = {
{ .compatible = "ppc4xx-rng", },
{ .compatible = "amcc,ppc460ex-rng", },
{ .compatible = "amcc,ppc440epx-rng", },
{},
};
static struct platform_driver ppc4xx_rng_driver = {
.driver = {
.name = MODULE_NAME,
.of_match_table = ppc4xx_rng_match,
},
.probe = ppc4xx_rng_probe,
.remove = ppc4xx_rng_remove,
};
module_platform_driver(ppc4xx_rng_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Josh Boyer <jwboyer@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("HW RNG driver for PPC 4xx processors");
|
