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b8cb3448 OJ |
1 | /* |
2 | * Copyright (C) 2006-2007 PA Semi, Inc | |
3 | * | |
4 | * Maintained by: Olof Johansson <olof@lixom.net> | |
5 | * | |
6 | * Driver for the PWRficient onchip rng | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
20 | */ | |
21 | ||
22 | #include <linux/module.h> | |
23 | #include <linux/kernel.h> | |
24 | #include <linux/platform_device.h> | |
25 | #include <linux/hw_random.h> | |
984e976f | 26 | #include <linux/delay.h> |
98cad101 | 27 | #include <linux/of_platform.h> |
b8cb3448 OJ |
28 | #include <asm/io.h> |
29 | ||
30 | #define SDCRNG_CTL_REG 0x00 | |
31 | #define SDCRNG_CTL_FVLD_M 0x0000f000 | |
32 | #define SDCRNG_CTL_FVLD_S 12 | |
33 | #define SDCRNG_CTL_KSZ 0x00000800 | |
34 | #define SDCRNG_CTL_RSRC_CRG 0x00000010 | |
35 | #define SDCRNG_CTL_RSRC_RRG 0x00000000 | |
36 | #define SDCRNG_CTL_CE 0x00000004 | |
37 | #define SDCRNG_CTL_RE 0x00000002 | |
38 | #define SDCRNG_CTL_DR 0x00000001 | |
39 | #define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG) | |
40 | #define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG) | |
41 | #define SDCRNG_VAL_REG 0x20 | |
42 | ||
43 | #define MODULE_NAME "pasemi_rng" | |
44 | ||
9aa6ad3e | 45 | static int pasemi_rng_data_present(struct hwrng *rng, int wait) |
b8cb3448 OJ |
46 | { |
47 | void __iomem *rng_regs = (void __iomem *)rng->priv; | |
984e976f | 48 | int data, i; |
b8cb3448 | 49 | |
984e976f PM |
50 | for (i = 0; i < 20; i++) { |
51 | data = (in_le32(rng_regs + SDCRNG_CTL_REG) | |
52 | & SDCRNG_CTL_FVLD_M) ? 1 : 0; | |
53 | if (data || !wait) | |
54 | break; | |
55 | udelay(10); | |
56 | } | |
57 | return data; | |
b8cb3448 OJ |
58 | } |
59 | ||
60 | static int pasemi_rng_data_read(struct hwrng *rng, u32 *data) | |
61 | { | |
62 | void __iomem *rng_regs = (void __iomem *)rng->priv; | |
63 | *data = in_le32(rng_regs + SDCRNG_VAL_REG); | |
64 | return 4; | |
65 | } | |
66 | ||
67 | static int pasemi_rng_init(struct hwrng *rng) | |
68 | { | |
69 | void __iomem *rng_regs = (void __iomem *)rng->priv; | |
70 | u32 ctl; | |
71 | ||
72 | ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ; | |
73 | out_le32(rng_regs + SDCRNG_CTL_REG, ctl); | |
74 | out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR); | |
75 | ||
76 | return 0; | |
77 | } | |
78 | ||
79 | static void pasemi_rng_cleanup(struct hwrng *rng) | |
80 | { | |
81 | void __iomem *rng_regs = (void __iomem *)rng->priv; | |
82 | u32 ctl; | |
83 | ||
84 | ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE; | |
85 | out_le32(rng_regs + SDCRNG_CTL_REG, | |
86 | in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl); | |
87 | } | |
88 | ||
89 | static struct hwrng pasemi_rng = { | |
90 | .name = MODULE_NAME, | |
91 | .init = pasemi_rng_init, | |
92 | .cleanup = pasemi_rng_cleanup, | |
93 | .data_present = pasemi_rng_data_present, | |
94 | .data_read = pasemi_rng_data_read, | |
95 | }; | |
96 | ||
97 | static int __devinit rng_probe(struct of_device *ofdev, | |
98 | const struct of_device_id *match) | |
99 | { | |
100 | void __iomem *rng_regs; | |
101 | struct device_node *rng_np = ofdev->node; | |
102 | struct resource res; | |
103 | int err = 0; | |
104 | ||
105 | err = of_address_to_resource(rng_np, 0, &res); | |
106 | if (err) | |
107 | return -ENODEV; | |
108 | ||
109 | rng_regs = ioremap(res.start, 0x100); | |
110 | ||
111 | if (!rng_regs) | |
112 | return -ENOMEM; | |
113 | ||
114 | pasemi_rng.priv = (unsigned long)rng_regs; | |
115 | ||
116 | printk(KERN_INFO "Registering PA Semi RNG\n"); | |
117 | ||
118 | err = hwrng_register(&pasemi_rng); | |
119 | ||
120 | if (err) | |
121 | iounmap(rng_regs); | |
122 | ||
123 | return err; | |
124 | } | |
125 | ||
126 | static int __devexit rng_remove(struct of_device *dev) | |
127 | { | |
128 | void __iomem *rng_regs = (void __iomem *)pasemi_rng.priv; | |
129 | ||
130 | hwrng_unregister(&pasemi_rng); | |
131 | iounmap(rng_regs); | |
132 | ||
133 | return 0; | |
134 | } | |
135 | ||
136 | static struct of_device_id rng_match[] = { | |
0d08a847 OJ |
137 | { .compatible = "1682m-rng", }, |
138 | { .compatible = "pasemi,pwrficient-rng", }, | |
139 | { }, | |
b8cb3448 OJ |
140 | }; |
141 | ||
142 | static struct of_platform_driver rng_driver = { | |
143 | .name = "pasemi-rng", | |
144 | .match_table = rng_match, | |
145 | .probe = rng_probe, | |
146 | .remove = rng_remove, | |
147 | }; | |
148 | ||
149 | static int __init rng_init(void) | |
150 | { | |
151 | return of_register_platform_driver(&rng_driver); | |
152 | } | |
153 | module_init(rng_init); | |
154 | ||
155 | static void __exit rng_exit(void) | |
156 | { | |
157 | of_unregister_platform_driver(&rng_driver); | |
158 | } | |
159 | module_exit(rng_exit); | |
160 | ||
161 | MODULE_LICENSE("GPL"); | |
162 | MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>"); | |
163 | MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor"); |