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1 | /* |
2 | * driver/char/hw_random/omap-rng.c | |
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 | |
13 | * Author: Juha Yrj��<juha.yrjola@nokia.com> | |
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> |
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31 | #include <linux/hw_random.h> |
32 | ||
33 | #include <asm/io.h> | |
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34 | |
35 | #define RNG_OUT_REG 0x00 /* Output register */ | |
36 | #define RNG_STAT_REG 0x04 /* Status register | |
37 | [0] = STAT_BUSY */ | |
38 | #define RNG_ALARM_REG 0x24 /* Alarm register | |
39 | [7:0] = ALARM_COUNTER */ | |
40 | #define RNG_CONFIG_REG 0x28 /* Configuration register | |
41 | [11:6] = RESET_COUNT | |
42 | [5:3] = RING2_DELAY | |
43 | [2:0] = RING1_DELAY */ | |
44 | #define RNG_REV_REG 0x3c /* Revision register | |
45 | [7:0] = REV_NB */ | |
46 | #define RNG_MASK_REG 0x40 /* Mask and reset register | |
47 | [2] = IT_EN | |
48 | [1] = SOFTRESET | |
49 | [0] = AUTOIDLE */ | |
50 | #define RNG_SYSSTATUS 0x44 /* System status | |
51 | [0] = RESETDONE */ | |
52 | ||
53 | static void __iomem *rng_base; | |
54 | static struct clk *rng_ick; | |
af2bc7d2 | 55 | static struct platform_device *rng_dev; |
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56 | |
57 | static u32 omap_rng_read_reg(int reg) | |
58 | { | |
59 | return __raw_readl(rng_base + reg); | |
60 | } | |
61 | ||
62 | static void omap_rng_write_reg(int reg, u32 val) | |
63 | { | |
64 | __raw_writel(val, rng_base + reg); | |
65 | } | |
66 | ||
67 | /* REVISIT: Does the status bit really work on 16xx? */ | |
68 | static int omap_rng_data_present(struct hwrng *rng) | |
69 | { | |
70 | return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1; | |
71 | } | |
72 | ||
73 | static int omap_rng_data_read(struct hwrng *rng, u32 *data) | |
74 | { | |
75 | *data = omap_rng_read_reg(RNG_OUT_REG); | |
76 | ||
77 | return 4; | |
78 | } | |
79 | ||
80 | static struct hwrng omap_rng_ops = { | |
81 | .name = "omap", | |
82 | .data_present = omap_rng_data_present, | |
83 | .data_read = omap_rng_data_read, | |
84 | }; | |
85 | ||
af2bc7d2 | 86 | static int __init omap_rng_probe(struct platform_device *pdev) |
ebc915ad | 87 | { |
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88 | struct resource *res, *mem; |
89 | int ret; | |
90 | ||
91 | /* | |
92 | * A bit ugly, and it will never actually happen but there can | |
93 | * be only one RNG and this catches any bork | |
94 | */ | |
95 | BUG_ON(rng_dev); | |
96 | ||
af2bc7d2 | 97 | if (cpu_is_omap24xx()) { |
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98 | rng_ick = clk_get(NULL, "rng_ick"); |
99 | if (IS_ERR(rng_ick)) { | |
af2bc7d2 | 100 | dev_err(&pdev->dev, "Could not get rng_ick\n"); |
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101 | ret = PTR_ERR(rng_ick); |
102 | return ret; | |
af2bc7d2 DB |
103 | } else |
104 | clk_enable(rng_ick); | |
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105 | } |
106 | ||
107 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
108 | ||
109 | if (!res) | |
110 | return -ENOENT; | |
111 | ||
112 | mem = request_mem_region(res->start, res->end - res->start + 1, | |
113 | pdev->name); | |
114 | if (mem == NULL) | |
115 | return -EBUSY; | |
116 | ||
af2bc7d2 | 117 | dev_set_drvdata(&pdev->dev, mem); |
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118 | rng_base = (u32 __iomem *)io_p2v(res->start); |
119 | ||
120 | ret = hwrng_register(&omap_rng_ops); | |
121 | if (ret) { | |
122 | release_resource(mem); | |
123 | rng_base = NULL; | |
124 | return ret; | |
125 | } | |
126 | ||
af2bc7d2 | 127 | dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n", |
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128 | omap_rng_read_reg(RNG_REV_REG)); |
129 | omap_rng_write_reg(RNG_MASK_REG, 0x1); | |
130 | ||
af2bc7d2 | 131 | rng_dev = pdev; |
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132 | |
133 | return 0; | |
134 | } | |
135 | ||
af2bc7d2 | 136 | static int __exit omap_rng_remove(struct platform_device *pdev) |
ebc915ad | 137 | { |
af2bc7d2 | 138 | struct resource *mem = dev_get_drvdata(&pdev->dev); |
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139 | |
140 | hwrng_unregister(&omap_rng_ops); | |
141 | ||
142 | omap_rng_write_reg(RNG_MASK_REG, 0x0); | |
143 | ||
144 | if (cpu_is_omap24xx()) { | |
af2bc7d2 | 145 | clk_disable(rng_ick); |
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146 | clk_put(rng_ick); |
147 | } | |
148 | ||
149 | release_resource(mem); | |
150 | rng_base = NULL; | |
151 | ||
152 | return 0; | |
153 | } | |
154 | ||
155 | #ifdef CONFIG_PM | |
156 | ||
af2bc7d2 | 157 | static int omap_rng_suspend(struct platform_device *pdev, pm_message_t message) |
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158 | { |
159 | omap_rng_write_reg(RNG_MASK_REG, 0x0); | |
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160 | return 0; |
161 | } | |
162 | ||
af2bc7d2 | 163 | static int omap_rng_resume(struct platform_device *pdev) |
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164 | { |
165 | omap_rng_write_reg(RNG_MASK_REG, 0x1); | |
af2bc7d2 | 166 | return 0; |
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167 | } |
168 | ||
169 | #else | |
170 | ||
171 | #define omap_rng_suspend NULL | |
172 | #define omap_rng_resume NULL | |
173 | ||
174 | #endif | |
175 | ||
176 | ||
af2bc7d2 DB |
177 | static struct platform_driver omap_rng_driver = { |
178 | .driver = { | |
179 | .name = "omap_rng", | |
180 | .owner = THIS_MODULE, | |
181 | }, | |
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182 | .probe = omap_rng_probe, |
183 | .remove = __exit_p(omap_rng_remove), | |
184 | .suspend = omap_rng_suspend, | |
185 | .resume = omap_rng_resume | |
186 | }; | |
187 | ||
188 | static int __init omap_rng_init(void) | |
189 | { | |
190 | if (!cpu_is_omap16xx() && !cpu_is_omap24xx()) | |
191 | return -ENODEV; | |
192 | ||
af2bc7d2 | 193 | return platform_driver_register(&omap_rng_driver); |
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194 | } |
195 | ||
196 | static void __exit omap_rng_exit(void) | |
197 | { | |
af2bc7d2 | 198 | platform_driver_unregister(&omap_rng_driver); |
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199 | } |
200 | ||
201 | module_init(omap_rng_init); | |
202 | module_exit(omap_rng_exit); | |
203 | ||
204 | MODULE_AUTHOR("Deepak Saxena (and others)"); | |
205 | MODULE_LICENSE("GPL"); |