[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/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 exynos_rng_probe(struct platform_device *pdev)
{
	struct exynos_rng *exynos_rng;
	struct resource *res;

	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;
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(exynos_rng->mem))
		return PTR_ERR(exynos_rng->mem);

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

	hwrng_unregister(&exynos_rng->rng);

	return 0;
}

#ifdef CONFIG_PM
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);
}
#endif

static 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		= 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>
b329669e JL	25	#include <linux/io.h>
	26	#include <linux/platform_device.h>
	27	#include <linux/clk.h>
	28	#include <linux/pm_runtime.h>
	29	#include <linux/err.h>
	30
	31	#define EXYNOS_PRNG_STATUS_OFFSET 0x10
	32	#define EXYNOS_PRNG_SEED_OFFSET 0x140
	33	#define EXYNOS_PRNG_OUT1_OFFSET 0x160
	34	#define SEED_SETTING_DONE BIT(1)
	35	#define PRNG_START 0x18
	36	#define PRNG_DONE BIT(5)
	37	#define EXYNOS_AUTOSUSPEND_DELAY 100
	38
	39	struct exynos_rng {
	40	struct device *dev;
	41	struct hwrng rng;
	42	void __iomem *mem;
	43	struct clk *clk;
	44	};
	45
	46	static u32 exynos_rng_readl(struct exynos_rng *rng, u32 offset)
	47	{
	48	return __raw_readl(rng->mem + offset);
	49	}
	50
	51	static void exynos_rng_writel(struct exynos_rng *rng, u32 val, u32 offset)
	52	{
	53	__raw_writel(val, rng->mem + offset);
	54	}
	55
	56	static int exynos_init(struct hwrng *rng)
	57	{
	58	struct exynos_rng *exynos_rng = container_of(rng,
	59	struct exynos_rng, rng);
	60	int i;
	61	int ret = 0;
	62
	63	pm_runtime_get_sync(exynos_rng->dev);
	64
	65	for (i = 0 ; i < 5 ; i++)
	66	exynos_rng_writel(exynos_rng, jiffies,
	67	EXYNOS_PRNG_SEED_OFFSET + 4*i);
	68
	69	if (!(exynos_rng_readl(exynos_rng, EXYNOS_PRNG_STATUS_OFFSET)
	70	& SEED_SETTING_DONE))
	71	ret = -EIO;
	72
	73	pm_runtime_put_noidle(exynos_rng->dev);
	74
	75	return ret;
	76	}
	77
	78	static int exynos_read(struct hwrng rng, void buf,
	79	size_t max, bool wait)
	80	{
	81	struct exynos_rng *exynos_rng = container_of(rng,
	82	struct exynos_rng, rng);
	83	u32 *data = buf;
	84
	85	pm_runtime_get_sync(exynos_rng->dev);
	86
	87	exynos_rng_writel(exynos_rng, PRNG_START, 0);
	88
89	while (!(exynos_rng_readl(exynos_rng,
90	EXYNOS_PRNG_STATUS_OFFSET) & PRNG_DONE))
91	cpu_relax();
92
93	exynos_rng_writel(exynos_rng, PRNG_DONE, EXYNOS_PRNG_STATUS_OFFSET);
94
95	*data = exynos_rng_readl(exynos_rng, EXYNOS_PRNG_OUT1_OFFSET);
96
97	pm_runtime_mark_last_busy(exynos_rng->dev);
98	pm_runtime_autosuspend(exynos_rng->dev);
99
100	return 4;
101	}
102
bcd2982a	103	static int exynos_rng_probe(struct platform_device *pdev)
b329669e JL	104	{
b329669e JL	105	struct exynos_rng *exynos_rng;
c7c9e1c3	106	struct resource *res;
b329669e JL	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
c7c9e1c3 TR	123	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	124	exynos_rng->mem = devm_ioremap_resource(&pdev->dev, res);
	125	if (IS_ERR(exynos_rng->mem))
	126	return PTR_ERR(exynos_rng->mem);
b329669e JL	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
39af33fc	137	static int exynos_rng_remove(struct platform_device *pdev)
b329669e JL	138	{
	139	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
	140
	141	hwrng_unregister(&exynos_rng->rng);
	142
	143	return 0;
	144	}
	145
2d3867d0	146	#ifdef CONFIG_PM
b329669e JL	147	static int exynos_rng_runtime_suspend(struct device *dev)
	148	{
	149	struct platform_device *pdev = to_platform_device(dev);
	150	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
	151
	152	clk_disable_unprepare(exynos_rng->clk);
	153
	154	return 0;
	155	}
	156
	157	static int exynos_rng_runtime_resume(struct device *dev)
	158	{
	159	struct platform_device *pdev = to_platform_device(dev);
	160	struct exynos_rng *exynos_rng = platform_get_drvdata(pdev);
	161
	162	return clk_prepare_enable(exynos_rng->clk);
	163	}
a80c5422	164	#endif
b329669e	165
ef4458a1	166	static UNIVERSAL_DEV_PM_OPS(exynos_rng_pm_ops, exynos_rng_runtime_suspend,
b329669e JL	167	exynos_rng_runtime_resume, NULL);
	168
	169	static struct platform_driver exynos_rng_driver = {
	170	.driver = {
	171	.name = "exynos-rng",
	172	.owner = THIS_MODULE,
	173	.pm = &exynos_rng_pm_ops,
	174	},
	175	.probe = exynos_rng_probe,
bcd2982a	176	.remove = exynos_rng_remove,
b329669e JL	177	};
	178
	179	module_platform_driver(exynos_rng_driver);
	180
	181	MODULE_DESCRIPTION("EXYNOS 4 H/W Random Number Generator driver");
	182	MODULE_AUTHOR("Jonghwa Lee <jonghwa3.lee@samsung.com>");
	183	MODULE_LICENSE("GPL");