Commit | Line | Data |
---|---|---|
ebc915ad | 1 | /* |
f30c2269 | 2 | * drivers/char/hw_random/omap-rng.c |
ebc915ad MB |
3 | * |
4 | * RNG driver for TI OMAP CPU family | |
5 | * | |
6 | * Author: Deepak Saxena <dsaxena@plexity.net> | |
7 | * | |
8 | * Copyright 2005 (c) MontaVista Software, Inc. | |
9 | * | |
10 | * Mostly based on original driver: | |
11 | * | |
12 | * Copyright (C) 2005 Nokia Corporation | |
96de0e25 | 13 | * Author: Juha Yrjölä <juha.yrjola@nokia.com> |
ebc915ad MB |
14 | * |
15 | * This file is licensed under the terms of the GNU General Public | |
16 | * License version 2. This program is licensed "as is" without any | |
17 | * warranty of any kind, whether express or implied. | |
18 | * | |
19 | * TODO: | |
20 | * | |
21 | * - Make status updated be interrupt driven so we don't poll | |
22 | * | |
23 | */ | |
24 | ||
25 | #include <linux/module.h> | |
26 | #include <linux/init.h> | |
27 | #include <linux/random.h> | |
af2bc7d2 | 28 | #include <linux/clk.h> |
ebc915ad | 29 | #include <linux/err.h> |
af2bc7d2 | 30 | #include <linux/platform_device.h> |
ebc915ad | 31 | #include <linux/hw_random.h> |
984e976f | 32 | #include <linux/delay.h> |
ebc915ad MB |
33 | |
34 | #include <asm/io.h> | |
ebc915ad MB |
35 | |
36 | #define RNG_OUT_REG 0x00 /* Output register */ | |
37 | #define RNG_STAT_REG 0x04 /* Status register | |
38 | [0] = STAT_BUSY */ | |
39 | #define RNG_ALARM_REG 0x24 /* Alarm register | |
40 | [7:0] = ALARM_COUNTER */ | |
41 | #define RNG_CONFIG_REG 0x28 /* Configuration register | |
42 | [11:6] = RESET_COUNT | |
43 | [5:3] = RING2_DELAY | |
44 | [2:0] = RING1_DELAY */ | |
45 | #define RNG_REV_REG 0x3c /* Revision register | |
46 | [7:0] = REV_NB */ | |
47 | #define RNG_MASK_REG 0x40 /* Mask and reset register | |
48 | [2] = IT_EN | |
49 | [1] = SOFTRESET | |
50 | [0] = AUTOIDLE */ | |
51 | #define RNG_SYSSTATUS 0x44 /* System status | |
52 | [0] = RESETDONE */ | |
53 | ||
54 | static void __iomem *rng_base; | |
55 | static struct clk *rng_ick; | |
af2bc7d2 | 56 | static struct platform_device *rng_dev; |
ebc915ad MB |
57 | |
58 | static u32 omap_rng_read_reg(int reg) | |
59 | { | |
60 | return __raw_readl(rng_base + reg); | |
61 | } | |
62 | ||
63 | static void omap_rng_write_reg(int reg, u32 val) | |
64 | { | |
65 | __raw_writel(val, rng_base + reg); | |
66 | } | |
67 | ||
68 | /* REVISIT: Does the status bit really work on 16xx? */ | |
984e976f | 69 | static int omap_rng_data_present(struct hwrng *rng, int wait) |
ebc915ad | 70 | { |
984e976f PM |
71 | int data, i; |
72 | ||
73 | for (i = 0; i < 20; i++) { | |
74 | data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1; | |
75 | if (data || !wait) | |
76 | break; | |
77 | udelay(10); | |
78 | } | |
79 | return data; | |
ebc915ad MB |
80 | } |
81 | ||
82 | static int omap_rng_data_read(struct hwrng *rng, u32 *data) | |
83 | { | |
84 | *data = omap_rng_read_reg(RNG_OUT_REG); | |
85 | ||
86 | return 4; | |
87 | } | |
88 | ||
89 | static struct hwrng omap_rng_ops = { | |
90 | .name = "omap", | |
91 | .data_present = omap_rng_data_present, | |
92 | .data_read = omap_rng_data_read, | |
93 | }; | |
94 | ||
af2bc7d2 | 95 | static int __init omap_rng_probe(struct platform_device *pdev) |
ebc915ad | 96 | { |
ebc915ad MB |
97 | struct resource *res, *mem; |
98 | int ret; | |
99 | ||
100 | /* | |
101 | * A bit ugly, and it will never actually happen but there can | |
102 | * be only one RNG and this catches any bork | |
103 | */ | |
104 | BUG_ON(rng_dev); | |
105 | ||
af2bc7d2 | 106 | if (cpu_is_omap24xx()) { |
ebc915ad MB |
107 | rng_ick = clk_get(NULL, "rng_ick"); |
108 | if (IS_ERR(rng_ick)) { | |
af2bc7d2 | 109 | dev_err(&pdev->dev, "Could not get rng_ick\n"); |
ebc915ad MB |
110 | ret = PTR_ERR(rng_ick); |
111 | return ret; | |
af2bc7d2 DB |
112 | } else |
113 | clk_enable(rng_ick); | |
ebc915ad MB |
114 | } |
115 | ||
116 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
117 | ||
118 | if (!res) | |
119 | return -ENOENT; | |
120 | ||
121 | mem = request_mem_region(res->start, res->end - res->start + 1, | |
122 | pdev->name); | |
123 | if (mem == NULL) | |
124 | return -EBUSY; | |
125 | ||
af2bc7d2 | 126 | dev_set_drvdata(&pdev->dev, mem); |
ebc915ad MB |
127 | rng_base = (u32 __iomem *)io_p2v(res->start); |
128 | ||
129 | ret = hwrng_register(&omap_rng_ops); | |
130 | if (ret) { | |
131 | release_resource(mem); | |
132 | rng_base = NULL; | |
133 | return ret; | |
134 | } | |
135 | ||
af2bc7d2 | 136 | dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n", |
ebc915ad MB |
137 | omap_rng_read_reg(RNG_REV_REG)); |
138 | omap_rng_write_reg(RNG_MASK_REG, 0x1); | |
139 | ||
af2bc7d2 | 140 | rng_dev = pdev; |
ebc915ad MB |
141 | |
142 | return 0; | |
143 | } | |
144 | ||
af2bc7d2 | 145 | static int __exit omap_rng_remove(struct platform_device *pdev) |
ebc915ad | 146 | { |
af2bc7d2 | 147 | struct resource *mem = dev_get_drvdata(&pdev->dev); |
ebc915ad MB |
148 | |
149 | hwrng_unregister(&omap_rng_ops); | |
150 | ||
151 | omap_rng_write_reg(RNG_MASK_REG, 0x0); | |
152 | ||
153 | if (cpu_is_omap24xx()) { | |
af2bc7d2 | 154 | clk_disable(rng_ick); |
ebc915ad MB |
155 | clk_put(rng_ick); |
156 | } | |
157 | ||
158 | release_resource(mem); | |
159 | rng_base = NULL; | |
160 | ||
161 | return 0; | |
162 | } | |
163 | ||
164 | #ifdef CONFIG_PM | |
165 | ||
af2bc7d2 | 166 | static int omap_rng_suspend(struct platform_device *pdev, pm_message_t message) |
ebc915ad MB |
167 | { |
168 | omap_rng_write_reg(RNG_MASK_REG, 0x0); | |
ebc915ad MB |
169 | return 0; |
170 | } | |
171 | ||
af2bc7d2 | 172 | static int omap_rng_resume(struct platform_device *pdev) |
ebc915ad MB |
173 | { |
174 | omap_rng_write_reg(RNG_MASK_REG, 0x1); | |
af2bc7d2 | 175 | return 0; |
ebc915ad MB |
176 | } |
177 | ||
178 | #else | |
179 | ||
180 | #define omap_rng_suspend NULL | |
181 | #define omap_rng_resume NULL | |
182 | ||
183 | #endif | |
184 | ||
185 | ||
af2bc7d2 DB |
186 | static struct platform_driver omap_rng_driver = { |
187 | .driver = { | |
188 | .name = "omap_rng", | |
189 | .owner = THIS_MODULE, | |
190 | }, | |
ebc915ad MB |
191 | .probe = omap_rng_probe, |
192 | .remove = __exit_p(omap_rng_remove), | |
193 | .suspend = omap_rng_suspend, | |
194 | .resume = omap_rng_resume | |
195 | }; | |
196 | ||
197 | static int __init omap_rng_init(void) | |
198 | { | |
199 | if (!cpu_is_omap16xx() && !cpu_is_omap24xx()) | |
200 | return -ENODEV; | |
201 | ||
af2bc7d2 | 202 | return platform_driver_register(&omap_rng_driver); |
ebc915ad MB |
203 | } |
204 | ||
205 | static void __exit omap_rng_exit(void) | |
206 | { | |
af2bc7d2 | 207 | platform_driver_unregister(&omap_rng_driver); |
ebc915ad MB |
208 | } |
209 | ||
210 | module_init(omap_rng_init); | |
211 | module_exit(omap_rng_exit); | |
212 | ||
213 | MODULE_AUTHOR("Deepak Saxena (and others)"); | |
214 | MODULE_LICENSE("GPL"); |