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677d3e2f PK |
1 | /* |
2 | * Copyright (c) 2011 Peter Korsgaard <jacmet@sunsite.dk> | |
3 | * | |
4 | * This file is licensed under the terms of the GNU General Public | |
5 | * License version 2. This program is licensed "as is" without any | |
6 | * warranty of any kind, whether express or implied. | |
7 | */ | |
8 | ||
9 | #include <linux/kernel.h> | |
10 | #include <linux/module.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/err.h> | |
13 | #include <linux/clk.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/hw_random.h> | |
16 | #include <linux/platform_device.h> | |
17 | ||
18 | #define TRNG_CR 0x00 | |
19 | #define TRNG_ISR 0x1c | |
20 | #define TRNG_ODATA 0x50 | |
21 | ||
22 | #define TRNG_KEY 0x524e4700 /* RNG */ | |
23 | ||
24 | struct atmel_trng { | |
25 | struct clk *clk; | |
26 | void __iomem *base; | |
27 | struct hwrng rng; | |
28 | }; | |
29 | ||
30 | static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max, | |
31 | bool wait) | |
32 | { | |
33 | struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng); | |
34 | u32 *data = buf; | |
35 | ||
36 | /* data ready? */ | |
37 | if (readl(trng->base + TRNG_ODATA) & 1) { | |
38 | *data = readl(trng->base + TRNG_ODATA); | |
39 | return 4; | |
40 | } else | |
41 | return 0; | |
42 | } | |
43 | ||
44 | static int atmel_trng_probe(struct platform_device *pdev) | |
45 | { | |
46 | struct atmel_trng *trng; | |
47 | struct resource *res; | |
48 | int ret; | |
49 | ||
50 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
51 | if (!res) | |
52 | return -EINVAL; | |
53 | ||
54 | trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); | |
55 | if (!trng) | |
56 | return -ENOMEM; | |
57 | ||
58 | if (!devm_request_mem_region(&pdev->dev, res->start, | |
59 | resource_size(res), pdev->name)) | |
60 | return -EBUSY; | |
61 | ||
62 | trng->base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); | |
63 | if (!trng->base) | |
64 | return -EBUSY; | |
65 | ||
66 | trng->clk = clk_get(&pdev->dev, NULL); | |
67 | if (IS_ERR(trng->clk)) | |
68 | return PTR_ERR(trng->clk); | |
69 | ||
70 | ret = clk_enable(trng->clk); | |
71 | if (ret) | |
72 | goto err_enable; | |
73 | ||
74 | writel(TRNG_KEY | 1, trng->base + TRNG_CR); | |
75 | trng->rng.name = pdev->name; | |
76 | trng->rng.read = atmel_trng_read; | |
77 | ||
78 | ret = hwrng_register(&trng->rng); | |
79 | if (ret) | |
80 | goto err_register; | |
81 | ||
82 | platform_set_drvdata(pdev, trng); | |
83 | ||
84 | return 0; | |
85 | ||
86 | err_register: | |
87 | clk_disable(trng->clk); | |
88 | err_enable: | |
89 | clk_put(trng->clk); | |
90 | ||
91 | return ret; | |
92 | } | |
93 | ||
94 | static int __devexit atmel_trng_remove(struct platform_device *pdev) | |
95 | { | |
96 | struct atmel_trng *trng = platform_get_drvdata(pdev); | |
97 | ||
98 | hwrng_unregister(&trng->rng); | |
99 | ||
100 | writel(TRNG_KEY, trng->base + TRNG_CR); | |
101 | clk_disable(trng->clk); | |
102 | clk_put(trng->clk); | |
103 | ||
104 | platform_set_drvdata(pdev, NULL); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | #ifdef CONFIG_PM | |
110 | static int atmel_trng_suspend(struct device *dev) | |
111 | { | |
112 | struct atmel_trng *trng = dev_get_drvdata(dev); | |
113 | ||
114 | clk_disable(trng->clk); | |
115 | ||
116 | return 0; | |
117 | } | |
118 | ||
119 | static int atmel_trng_resume(struct device *dev) | |
120 | { | |
121 | struct atmel_trng *trng = dev_get_drvdata(dev); | |
122 | ||
123 | return clk_enable(trng->clk); | |
124 | } | |
125 | ||
126 | static const struct dev_pm_ops atmel_trng_pm_ops = { | |
127 | .suspend = atmel_trng_suspend, | |
128 | .resume = atmel_trng_resume, | |
129 | }; | |
130 | #endif /* CONFIG_PM */ | |
131 | ||
132 | static struct platform_driver atmel_trng_driver = { | |
133 | .probe = atmel_trng_probe, | |
134 | .remove = __devexit_p(atmel_trng_remove), | |
135 | .driver = { | |
136 | .name = "atmel-trng", | |
137 | .owner = THIS_MODULE, | |
138 | #ifdef CONFIG_PM | |
139 | .pm = &atmel_trng_pm_ops, | |
140 | #endif /* CONFIG_PM */ | |
141 | }, | |
142 | }; | |
143 | ||
b21cb324 | 144 | module_platform_driver(atmel_trng_driver); |
677d3e2f PK |
145 | |
146 | MODULE_LICENSE("GPL"); | |
147 | MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>"); | |
148 | MODULE_DESCRIPTION("Atmel true random number generator driver"); |