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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
24struct atmel_trng {
25 struct clk *clk;
26 void __iomem *base;
27 struct hwrng rng;
28};
29
30static 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_ISR) & 1) {
38 *data = readl(trng->base + TRNG_ODATA);
39 /*
40 ensure data ready is only set again AFTER the next data
41 word is ready in case it got set between checking ISR
42 and reading ODATA, so we don't risk re-reading the
43 same word
44 */
45 readl(trng->base + TRNG_ISR);
46 return 4;
47 } else
48 return 0;
49}
50
51static int atmel_trng_probe(struct platform_device *pdev)
52{
53 struct atmel_trng *trng;
54 struct resource *res;
55 int ret;
56
57 trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
58 if (!trng)
59 return -ENOMEM;
60
61 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
62 trng->base = devm_ioremap_resource(&pdev->dev, res);
63 if (IS_ERR(trng->base))
64 return PTR_ERR(trng->base);
65
66 trng->clk = devm_clk_get(&pdev->dev, NULL);
67 if (IS_ERR(trng->clk))
68 return PTR_ERR(trng->clk);
69
70 ret = clk_prepare_enable(trng->clk);
71 if (ret)
72 return ret;
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
86err_register:
87 clk_disable(trng->clk);
88 return ret;
89}
90
91static int atmel_trng_remove(struct platform_device *pdev)
92{
93 struct atmel_trng *trng = platform_get_drvdata(pdev);
94
95 hwrng_unregister(&trng->rng);
96
97 writel(TRNG_KEY, trng->base + TRNG_CR);
98 clk_disable_unprepare(trng->clk);
99
100 return 0;
101}
102
103#ifdef CONFIG_PM
104static int atmel_trng_suspend(struct device *dev)
105{
106 struct atmel_trng *trng = dev_get_drvdata(dev);
107
108 clk_disable_unprepare(trng->clk);
109
110 return 0;
111}
112
113static int atmel_trng_resume(struct device *dev)
114{
115 struct atmel_trng *trng = dev_get_drvdata(dev);
116
117 return clk_prepare_enable(trng->clk);
118}
119
120static const struct dev_pm_ops atmel_trng_pm_ops = {
121 .suspend = atmel_trng_suspend,
122 .resume = atmel_trng_resume,
123};
124#endif /* CONFIG_PM */
125
126static const struct of_device_id atmel_trng_dt_ids[] = {
127 { .compatible = "atmel,at91sam9g45-trng" },
128 { /* sentinel */ }
129};
130MODULE_DEVICE_TABLE(of, atmel_trng_dt_ids);
131
132static struct platform_driver atmel_trng_driver = {
133 .probe = atmel_trng_probe,
134 .remove = atmel_trng_remove,
135 .driver = {
136 .name = "atmel-trng",
137#ifdef CONFIG_PM
138 .pm = &atmel_trng_pm_ops,
139#endif /* CONFIG_PM */
140 .of_match_table = atmel_trng_dt_ids,
141 },
142};
143
144module_platform_driver(atmel_trng_driver);
145
146MODULE_LICENSE("GPL");
147MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
148MODULE_DESCRIPTION("Atmel true random number generator driver");
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
24struct atmel_trng {
25 struct clk *clk;
26 void __iomem *base;
27 struct hwrng rng;
28};
29
30static 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_ISR) & 1) {
38 *data = readl(trng->base + TRNG_ODATA);
39 /*
40 ensure data ready is only set again AFTER the next data
41 word is ready in case it got set between checking ISR
42 and reading ODATA, so we don't risk re-reading the
43 same word
44 */
45 readl(trng->base + TRNG_ISR);
46 return 4;
47 } else
48 return 0;
49}
50
51static void atmel_trng_enable(struct atmel_trng *trng)
52{
53 writel(TRNG_KEY | 1, trng->base + TRNG_CR);
54}
55
56static void atmel_trng_disable(struct atmel_trng *trng)
57{
58 writel(TRNG_KEY, trng->base + TRNG_CR);
59}
60
61static int atmel_trng_probe(struct platform_device *pdev)
62{
63 struct atmel_trng *trng;
64 struct resource *res;
65 int ret;
66
67 trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
68 if (!trng)
69 return -ENOMEM;
70
71 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
72 trng->base = devm_ioremap_resource(&pdev->dev, res);
73 if (IS_ERR(trng->base))
74 return PTR_ERR(trng->base);
75
76 trng->clk = devm_clk_get(&pdev->dev, NULL);
77 if (IS_ERR(trng->clk))
78 return PTR_ERR(trng->clk);
79
80 ret = clk_prepare_enable(trng->clk);
81 if (ret)
82 return ret;
83
84 atmel_trng_enable(trng);
85 trng->rng.name = pdev->name;
86 trng->rng.read = atmel_trng_read;
87
88 ret = hwrng_register(&trng->rng);
89 if (ret)
90 goto err_register;
91
92 platform_set_drvdata(pdev, trng);
93
94 return 0;
95
96err_register:
97 clk_disable_unprepare(trng->clk);
98 return ret;
99}
100
101static int atmel_trng_remove(struct platform_device *pdev)
102{
103 struct atmel_trng *trng = platform_get_drvdata(pdev);
104
105 hwrng_unregister(&trng->rng);
106
107 atmel_trng_disable(trng);
108 clk_disable_unprepare(trng->clk);
109
110 return 0;
111}
112
113#ifdef CONFIG_PM
114static int atmel_trng_suspend(struct device *dev)
115{
116 struct atmel_trng *trng = dev_get_drvdata(dev);
117
118 atmel_trng_disable(trng);
119 clk_disable_unprepare(trng->clk);
120
121 return 0;
122}
123
124static int atmel_trng_resume(struct device *dev)
125{
126 struct atmel_trng *trng = dev_get_drvdata(dev);
127 int ret;
128
129 ret = clk_prepare_enable(trng->clk);
130 if (ret)
131 return ret;
132
133 atmel_trng_enable(trng);
134
135 return 0;
136}
137
138static const struct dev_pm_ops atmel_trng_pm_ops = {
139 .suspend = atmel_trng_suspend,
140 .resume = atmel_trng_resume,
141};
142#endif /* CONFIG_PM */
143
144static const struct of_device_id atmel_trng_dt_ids[] = {
145 { .compatible = "atmel,at91sam9g45-trng" },
146 { /* sentinel */ }
147};
148MODULE_DEVICE_TABLE(of, atmel_trng_dt_ids);
149
150static struct platform_driver atmel_trng_driver = {
151 .probe = atmel_trng_probe,
152 .remove = atmel_trng_remove,
153 .driver = {
154 .name = "atmel-trng",
155#ifdef CONFIG_PM
156 .pm = &atmel_trng_pm_ops,
157#endif /* CONFIG_PM */
158 .of_match_table = atmel_trng_dt_ids,
159 },
160};
161
162module_platform_driver(atmel_trng_driver);
163
164MODULE_LICENSE("GPL");
165MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
166MODULE_DESCRIPTION("Atmel true random number generator driver");