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

/*
 * exynos-rng.c - Random Number Generator driver for the exynos
 *
 * Copyright (C) 2012 Samsung Electronics
 * Jonghwa Lee <jonghwa3.lee@smasung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

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

#define EXYNOS_PRNG_STATUS_OFFSET	0x10
#define EXYNOS_PRNG_SEED_OFFSET		0x140
#define EXYNOS_PRNG_OUT1_OFFSET		0x160
#define SEED_SETTING_DONE		BIT(1)
#define PRNG_START			0x18
#define PRNG_DONE			BIT(5)
#define EXYNOS_AUTOSUSPEND_DELAY	100

struct exynos_rng {
	struct device *dev;
	struct hwrng rng;
	void __iomem *mem;
	struct clk *clk;
};

static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
{
	return	__raw_readl(rng->mem + offset);
}

static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
{
	__raw_writel(val, rng->mem + offset);
}

static int exynos_init(struct hwrng *rng)
{
	struct exynos_rng *exynos_rng = container_of(rng,
						struct exynos_rng, rng);
	int i;
	int ret = 0;

	pm_runtime_get_sync(exynos_rng->dev);

	for (i = 0 ; i < 5 ; i++)
		exynos_rng_writel(exynos_rng, jiffies,
				EXYNOS_PRNG_SEED_OFFSET + 4*i);

	if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
						 & SEED_SETTING_DONE))
		ret = -EIO;

	pm_runtime_put_noidle(exynos_rng->dev);

	return ret;
}

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

	pm_runtime_get_sync(exynos_rng->dev);

	exynos_rng_writel(exynos_rng, PRNG_START, 0);

	while (!(exynos_rng_readl(exynos_rng,
			EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
		cpu_relax();

	exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);

	*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);

	pm_runtime_mark_last_busy(exynos_rng->dev);
	pm_runtime_autosuspend(exynos_rng->dev);

	return 4;
}

static int __devinit exynos_rng_probe(struct platform_device *pdev)
{
	struct exynos_rng *exynos_rng;

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

	exynos_rng->dev = &pdev->dev;
	exynos_rng->rng.name = "exynos";
	exynos_rng->rng.init =	exynos_init;
	exynos_rng->rng.read = exynos_read;
	exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
	if (IS_ERR(exynos_rng->clk)) {
		dev_err(&pdev->dev, "Couldn't get clock.\n");
		return -ENOENT;
	}

	exynos_rng->mem = devm_request_and_ioremap(&pdev->dev,
			platform_get_resource(pdev, IORESOURCE_MEM, 0));
	if (!exynos_rng->mem)
		return -EBUSY;

	platform_set_drvdata(pdev, exynos_rng);

	pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
	pm_runtime_use_autosuspend(&pdev->dev);
	pm_runtime_enable(&pdev->dev);

	return hwrng_register(&exynos_rng->rng);
}

static int __devexit exynos_rng_remove(struct platform_device *pdev)
{
	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);

	hwrng_unregister(&exynos_rng->rng);

	return 0;
}

static int exynos_rng_runtime_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);

	clk_disable_unprepare(exynos_rng->clk);

	return 0;
}

static int exynos_rng_runtime_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);
	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);

	return clk_prepare_enable(exynos_rng->clk);
}


UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
					exynos_rng_runtime_resume, NULL);

static struct platform_driver exynos_rng_driver = {
	.driver		= {
		.name	= "exynos-rng",
		.owner	= THIS_MODULE,
		.pm	= &exynos_rng_pm_ops,
	},
	.probe		= exynos_rng_probe,
	.remove		= __devexit_p(exynos_rng_remove),
};

module_platform_driver(exynos_rng_driver);

MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
MODULE_LICENSE("GPL");
Commit	Line	Data
b329669e JL	1	/*
	2	* exynos-rng.c - Random Number Generator driver for the exynos
	3	*
	4	* Copyright (C) 2012 Samsung Electronics
	5	* Jonghwa Lee <jonghwa3.lee@smasung.com>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License as published by
	9	* the Free Software Foundation;
	10	*
	11	* This program is distributed in the hope that it will be useful,
	12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	* GNU General Public License for more details.
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* along with this program; if not, write to the Free Software
	18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	19	*
	20	*/
	21
	22	#include <linux/hw_random.h>
	23	#include <linux/kernel.h>
	24	#include <linux/module.h>
	25	#include <linux/init.h>
	26	#include <linux/io.h>
	27	#include <linux/platform_device.h>
	28	#include <linux/clk.h>
	29	#include <linux/pm_runtime.h>
	30	#include <linux/err.h>
	31
	32	#define EXYNOS_PRNG_STATUS_OFFSET 0x10
	33	#define EXYNOS_PRNG_SEED_OFFSET 0x140
	34	#define EXYNOS_PRNG_OUT1_OFFSET 0x160
	35	#define SEED_SETTING_DONE BIT(1)
	36	#define PRNG_START 0x18
	37	#define PRNG_DONE BIT(5)
	38	#define EXYNOS_AUTOSUSPEND_DELAY 100
	39
	40	struct exynos_rng {
	41	struct device *dev;
	42	struct hwrng rng;
	43	void __iomem *mem;
	44	struct clk *clk;
	45	};
	46
	47	static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
	48	{
	49	return __raw_readl(rng->mem + offset);
	50	}
	51
	52	static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
	53	{
	54	__raw_writel(val, rng->mem + offset);
	55	}
	56
	57	static int exynos_init(struct hwrng *rng)
	58	{
	59	struct exynos_rng *exynos_rng = container_of(rng,
	60	struct exynos_rng, rng);
	61	int i;
	62	int ret = 0;
	63
	64	pm_runtime_get_sync(exynos_rng->dev);
65
66	for (i = 0 ; i < 5 ; i++)
67	exynos_rng_writel(exynos_rng, jiffies,
68	EXYNOS_PRNG_SEED_OFFSET + 4*i);
69
70	if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
71	& SEED_SETTING_DONE))
72	ret = -EIO;
73
74	pm_runtime_put_noidle(exynos_rng->dev);
75
76	return ret;
77	}
78
79	static int exynos_read(struct hwrng rng, void buf,
80	size_t max, bool wait)
81	{
82	struct exynos_rng *exynos_rng = container_of(rng,
83	struct exynos_rng, rng);
84	u32 *data = buf;
85
86	pm_runtime_get_sync(exynos_rng->dev);
87
88	exynos_rng_writel(exynos_rng, PRNG_START, 0);
89
90	while (!(exynos_rng_readl(exynos_rng,
91	EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
92	cpu_relax();
93
94	exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
95
96	*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
97
98	pm_runtime_mark_last_busy(exynos_rng->dev);
99	pm_runtime_autosuspend(exynos_rng->dev);
100
101	return 4;
102	}
103
104	static int __devinit exynos_rng_probe(struct platform_device *pdev)
105	{
106	struct exynos_rng *exynos_rng;
107
108	exynos_rng = devm_kzalloc(&pdev->dev, sizeof(struct exynos_rng),
109	GFP_KERNEL);
110	if (!exynos_rng)
111	return -ENOMEM;
112
113	exynos_rng->dev = &pdev->dev;
114	exynos_rng->rng.name = "exynos";
115	exynos_rng->rng.init = exynos_init;
116	exynos_rng->rng.read = exynos_read;
117	exynos_rng->clk = devm_clk_get(&pdev->dev, "secss");
118	if (IS_ERR(exynos_rng->clk)) {
119	dev_err(&pdev->dev, "Couldn't get clock.\n");
120	return -ENOENT;
121	}
122
123	exynos_rng->mem = devm_request_and_ioremap(&pdev->dev,
124	platform_get_resource(pdev, IORESOURCE_MEM, 0));
125	if (!exynos_rng->mem)
126	return -EBUSY;
127
128	platform_set_drvdata(pdev, exynos_rng);
129
130	pm_runtime_set_autosuspend_delay(&pdev->dev, EXYNOS_AUTOSUSPEND_DELAY);
131	pm_runtime_use_autosuspend(&pdev->dev);
132	pm_runtime_enable(&pdev->dev);
133
134	return hwrng_register(&exynos_rng->rng);
135	}
136
137	static int __devexit exynos_rng_remove(struct platform_device *pdev)
138	{
139	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
140
141	hwrng_unregister(&exynos_rng->rng);
142
143	return 0;
144	}
145
146	static int exynos_rng_runtime_suspend(struct device *dev)
147	{
148	struct platform_device *pdev = to_platform_device(dev);
149	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
150
151	clk_disable_unprepare(exynos_rng->clk);
152
153	return 0;
154	}
155
156	static int exynos_rng_runtime_resume(struct device *dev)
157	{
158	struct platform_device *pdev = to_platform_device(dev);
159	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
160
161	return clk_prepare_enable(exynos_rng->clk);
162	}
163
164
165	UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
166	exynos_rng_runtime_resume, NULL);
167
168	static struct platform_driver exynos_rng_driver = {
169	.driver = {
170	.name = "exynos-rng",
171	.owner = THIS_MODULE,
172	.pm = &exynos_rng_pm_ops,
173	},
174	.probe = exynos_rng_probe,
175	.remove = __devexit_p(exynos_rng_remove),
176	};
177
178	module_platform_driver(exynos_rng_driver);
179
180	MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
181	MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
182	MODULE_LICENSE("GPL");