[linux-2.6-block.git] / drivers / char / hw_random / atmel-rng.c

/*
 * Copyright (c) 2011 Peter Korsgaard <jacmet@sunsite.dk>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/hw_random.h>
#include <linux/platform_device.h>

#define TRNG_CR		0x00
#define TRNG_ISR	0x1c
#define TRNG_ODATA	0x50

#define TRNG_KEY	0x524e4700 /* RNG */

struct atmel_trng {
	struct clk *clk;
	void __iomem *base;
	struct hwrng rng;
};

static int atmel_trng_read(struct hwrng *rng, void *buf, size_t max,
			   bool wait)
{
	struct atmel_trng *trng = container_of(rng, struct atmel_trng, rng);
	u32 *data = buf;

	/* data ready? */
	if (readl(trng->base + TRNG_ODATA) & 1) {
		*data = readl(trng->base + TRNG_ODATA);
		return 4;
	} else
		return 0;
}

static int atmel_trng_probe(struct platform_device *pdev)
{
	struct atmel_trng *trng;
	struct resource *res;
	int ret;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
		return -EINVAL;

	trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
	if (!trng)
		return -ENOMEM;

	if (!devm_request_mem_region(&pdev->dev, res->start,
				     resource_size(res), pdev->name))
		return -EBUSY;

	trng->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
	if (!trng->base)
		return -EBUSY;

	trng->clk = clk_get(&pdev->dev, NULL);
	if (IS_ERR(trng->clk))
		return PTR_ERR(trng->clk);

	ret = clk_enable(trng->clk);
	if (ret)
		goto err_enable;

	writel(TRNG_KEY | 1, trng->base + TRNG_CR);
	trng->rng.name = pdev->name;
	trng->rng.read = atmel_trng_read;

	ret = hwrng_register(&trng->rng);
	if (ret)
		goto err_register;

	platform_set_drvdata(pdev, trng);

	return 0;

err_register:
	clk_disable(trng->clk);
err_enable:
	clk_put(trng->clk);

	return ret;
}

static int __devexit atmel_trng_remove(struct platform_device *pdev)
{
	struct atmel_trng *trng = platform_get_drvdata(pdev);

	hwrng_unregister(&trng->rng);

	writel(TRNG_KEY, trng->base + TRNG_CR);
	clk_disable(trng->clk);
	clk_put(trng->clk);

	platform_set_drvdata(pdev, NULL);

	return 0;
}

#ifdef CONFIG_PM
static int atmel_trng_suspend(struct device *dev)
{
	struct atmel_trng *trng = dev_get_drvdata(dev);

	clk_disable(trng->clk);

	return 0;
}

static int atmel_trng_resume(struct device *dev)
{
	struct atmel_trng *trng = dev_get_drvdata(dev);

	return clk_enable(trng->clk);
}

static const struct dev_pm_ops atmel_trng_pm_ops = {
	.suspend	= atmel_trng_suspend,
	.resume		= atmel_trng_resume,
};
#endif /* CONFIG_PM */

static struct platform_driver atmel_trng_driver = {
	.probe		= atmel_trng_probe,
	.remove		= __devexit_p(atmel_trng_remove),
	.driver		= {
		.name	= "atmel-trng",
		.owner	= THIS_MODULE,
#ifdef CONFIG_PM
		.pm	= &atmel_trng_pm_ops,
#endif /* CONFIG_PM */
	},
};

static int __init atmel_trng_init(void)
{
	return platform_driver_register(&atmel_trng_driver);
}
module_init(atmel_trng_init);

static void __exit atmel_trng_exit(void)
{
	platform_driver_unregister(&atmel_trng_driver);
}
module_exit(atmel_trng_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
MODULE_DESCRIPTION("Atmel true random number generator driver");
Commit	Line	Data
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
144	static int __init atmel_trng_init(void)
145	{
146	return platform_driver_register(&atmel_trng_driver);
147	}
148	module_init(atmel_trng_init);
149
150	static void __exit atmel_trng_exit(void)
151	{
152	platform_driver_unregister(&atmel_trng_driver);
153	}
154	module_exit(atmel_trng_exit);
155
156	MODULE_LICENSE("GPL");
157	MODULE_AUTHOR("Peter Korsgaard <jacmet@sunsite.dk>");
158	MODULE_DESCRIPTION("Atmel true random number generator driver");