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

/*
 * omap-rng.c - RNG driver for TI OMAP CPU family
 *
 * Author: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2005 (c) MontaVista Software, Inc.
 *
 * Mostly based on original driver:
 *
 * Copyright (C) 2005 Nokia Corporation
 * Author: Juha Yrjölä <juha.yrjola@nokia.com>
 *
 * 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/module.h>
#include <linux/init.h>
#include <linux/random.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
#include <linux/delay.h>

#include <asm/io.h>

#include <plat/cpu.h>

#define RNG_OUT_REG		0x00		/* Output register */
#define RNG_STAT_REG		0x04		/* Status register
							[0] = STAT_BUSY */
#define RNG_ALARM_REG		0x24		/* Alarm register
							[7:0] = ALARM_COUNTER */
#define RNG_CONFIG_REG		0x28		/* Configuration register
							[11:6] = RESET_COUNT
							[5:3]  = RING2_DELAY
							[2:0]  = RING1_DELAY */
#define RNG_REV_REG		0x3c		/* Revision register
							[7:0] = REV_NB */
#define RNG_MASK_REG		0x40		/* Mask and reset register
							[2] = IT_EN
							[1] = SOFTRESET
							[0] = AUTOIDLE */
#define RNG_SYSSTATUS		0x44		/* System status
							[0] = RESETDONE */

static void __iomem *rng_base;
static struct clk *rng_ick;
static struct platform_device *rng_dev;

static inline u32 omap_rng_read_reg(int reg)
{
	return __raw_readl(rng_base + reg);
}

static inline void omap_rng_write_reg(int reg, u32 val)
{
	__raw_writel(val, rng_base + reg);
}

static int omap_rng_data_present(struct hwrng *rng, int wait)
{
	int data, i;

	for (i = 0; i < 20; i++) {
		data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
		if (data || !wait)
			break;
		/* RNG produces data fast enough (2+ MBit/sec, even
		 * during "rngtest" loads, that these delays don't
		 * seem to trigger.  We *could* use the RNG IRQ, but
		 * that'd be higher overhead ... so why bother?
		 */
		udelay(10);
	}
	return data;
}

static int omap_rng_data_read(struct hwrng *rng, u32 *data)
{
	*data = omap_rng_read_reg(RNG_OUT_REG);

	return 4;
}

static struct hwrng omap_rng_ops = {
	.name		= "omap",
	.data_present	= omap_rng_data_present,
	.data_read	= omap_rng_data_read,
};

static int __devinit omap_rng_probe(struct platform_device *pdev)
{
	struct resource *res;
	int ret;

	/*
	 * A bit ugly, and it will never actually happen but there can
	 * be only one RNG and this catches any bork
	 */
	if (rng_dev)
		return -EBUSY;

	if (cpu_is_omap24xx()) {
		rng_ick = clk_get(&pdev->dev, "ick");
		if (IS_ERR(rng_ick)) {
			dev_err(&pdev->dev, "Could not get rng_ick\n");
			ret = PTR_ERR(rng_ick);
			return ret;
		} else
			clk_enable(rng_ick);
	}

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	rng_base = devm_request_and_ioremap(&pdev->dev, res);
	if (!rng_base) {
		ret = -ENOMEM;
		goto err_ioremap;
	}
	dev_set_drvdata(&pdev->dev, res);

	ret = hwrng_register(&omap_rng_ops);
	if (ret)
		goto err_register;

	dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
		omap_rng_read_reg(RNG_REV_REG));
	omap_rng_write_reg(RNG_MASK_REG, 0x1);

	rng_dev = pdev;

	return 0;

err_register:
	rng_base = NULL;
err_ioremap:
	if (cpu_is_omap24xx()) {
		clk_disable(rng_ick);
		clk_put(rng_ick);
	}
	return ret;
}

static int __exit omap_rng_remove(struct platform_device *pdev)
{
	hwrng_unregister(&omap_rng_ops);

	omap_rng_write_reg(RNG_MASK_REG, 0x0);

	if (cpu_is_omap24xx()) {
		clk_disable(rng_ick);
		clk_put(rng_ick);
	}

	rng_base = NULL;

	return 0;
}

#ifdef CONFIG_PM_SLEEP

static int omap_rng_suspend(struct device *dev)
{
	omap_rng_write_reg(RNG_MASK_REG, 0x0);
	return 0;
}

static int omap_rng_resume(struct device *dev)
{
	omap_rng_write_reg(RNG_MASK_REG, 0x1);
	return 0;
}

static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
#define	OMAP_RNG_PM	(&omap_rng_pm)

#else

#define	OMAP_RNG_PM	NULL

#endif

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:omap_rng");

static struct platform_driver omap_rng_driver = {
	.driver = {
		.name		= "omap_rng",
		.owner		= THIS_MODULE,
		.pm		= OMAP_RNG_PM,
	},
	.probe		= omap_rng_probe,
	.remove		= __exit_p(omap_rng_remove),
};

static int __init omap_rng_init(void)
{
	if (!cpu_is_omap16xx() && !cpu_is_omap24xx())
		return -ENODEV;

	return platform_driver_register(&omap_rng_driver);
}

static void __exit omap_rng_exit(void)
{
	platform_driver_unregister(&omap_rng_driver);
}

module_init(omap_rng_init);
module_exit(omap_rng_exit);

MODULE_AUTHOR("Deepak Saxena (and others)");
MODULE_LICENSE("GPL");
Commit	Line	Data
ebc915ad	1	/*
c49a7f18	2	* omap-rng.c - RNG driver for TI OMAP CPU family
ebc915ad MB	3	*
	4	* Author: Deepak Saxena <dsaxena@plexity.net>
	5	*
	6	* Copyright 2005 (c) MontaVista Software, Inc.
	7	*
	8	* Mostly based on original driver:
	9	*
	10	* Copyright (C) 2005 Nokia Corporation
96de0e25	11	* Author: Juha Yrjölä <juha.yrjola@nokia.com>
ebc915ad MB	12	*
	13	* This file is licensed under the terms of the GNU General Public
	14	* License version 2. This program is licensed "as is" without any
	15	* warranty of any kind, whether express or implied.
ebc915ad MB	16	*/
	17
	18	#include <linux/module.h>
	19	#include <linux/init.h>
	20	#include <linux/random.h>
af2bc7d2	21	#include <linux/clk.h>
ebc915ad	22	#include <linux/err.h>
af2bc7d2	23	#include <linux/platform_device.h>
ebc915ad	24	#include <linux/hw_random.h>
984e976f	25	#include <linux/delay.h>
ebc915ad MB	26
ebc915ad MB	27	#include <asm/io.h>
ebc915ad	28
2c799cef TL	29	#include <plat/cpu.h>
2c799cef TL	30
ebc915ad MB	31	#define RNG_OUT_REG 0x00 /* Output register */
	32	#define RNG_STAT_REG 0x04 /* Status register
	33	[0] = STAT_BUSY */
	34	#define RNG_ALARM_REG 0x24 /* Alarm register
	35	[7:0] = ALARM_COUNTER */
	36	#define RNG_CONFIG_REG 0x28 /* Configuration register
	37	[11:6] = RESET_COUNT
	38	[5:3] = RING2_DELAY
	39	[2:0] = RING1_DELAY */
	40	#define RNG_REV_REG 0x3c /* Revision register
	41	[7:0] = REV_NB */
	42	#define RNG_MASK_REG 0x40 /* Mask and reset register
	43	[2] = IT_EN
	44	[1] = SOFTRESET
	45	[0] = AUTOIDLE */
	46	#define RNG_SYSSTATUS 0x44 /* System status
	47	[0] = RESETDONE */
	48
	49	static void __iomem *rng_base;
	50	static struct clk *rng_ick;
af2bc7d2	51	static struct platform_device *rng_dev;
ebc915ad	52
c49a7f18	53	static inline u32 omap_rng_read_reg(int reg)
ebc915ad MB	54	{
	55	return __raw_readl(rng_base + reg);
	56	}
	57
c49a7f18	58	static inline void omap_rng_write_reg(int reg, u32 val)
ebc915ad MB	59	{
	60	__raw_writel(val, rng_base + reg);
	61	}
	62
984e976f	63	static int omap_rng_data_present(struct hwrng *rng, int wait)
ebc915ad	64	{
984e976f PM	65	int data, i;
	66
	67	for (i = 0; i < 20; i++) {
	68	data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
	69	if (data \|\| !wait)
	70	break;
c49a7f18 DB	71	/* RNG produces data fast enough (2+ MBit/sec, even
	72	* during "rngtest" loads, that these delays don't
	73	* seem to trigger. We could use the RNG IRQ, but
	74	* that'd be higher overhead ... so why bother?
	75	*/
984e976f PM	76	udelay(10);
	77	}
	78	return data;
ebc915ad MB	79	}
	80
	81	static int omap_rng_data_read(struct hwrng rng, u32 data)
	82	{
	83	*data = omap_rng_read_reg(RNG_OUT_REG);
	84
	85	return 4;
	86	}
	87
	88	static struct hwrng omap_rng_ops = {
	89	.name = "omap",
	90	.data_present = omap_rng_data_present,
	91	.data_read = omap_rng_data_read,
	92	};
	93
9f171adc	94	static int __devinit omap_rng_probe(struct platform_device *pdev)
ebc915ad	95	{
c652759b	96	struct resource *res;
ebc915ad MB	97	int ret;
	98
	99	/*
	100	* A bit ugly, and it will never actually happen but there can
	101	* be only one RNG and this catches any bork
	102	*/
c49a7f18 DB	103	if (rng_dev)
c49a7f18 DB	104	return -EBUSY;
ebc915ad	105
af2bc7d2	106	if (cpu_is_omap24xx()) {
eeec7c8d	107	rng_ick = clk_get(&pdev->dev, "ick");
ebc915ad	108	if (IS_ERR(rng_ick)) {
af2bc7d2	109	dev_err(&pdev->dev, "Could not get rng_ick\n");
ebc915ad MB	110	ret = PTR_ERR(rng_ick);
ebc915ad MB	111	return ret;
af2bc7d2 DB	112	} else
af2bc7d2 DB	113	clk_enable(rng_ick);
ebc915ad MB	114	}
	115
	116	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	117
945478a7	118	rng_base = devm_request_and_ioremap(&pdev->dev, res);
55c381e4 RK	119	if (!rng_base) {
	120	ret = -ENOMEM;
	121	goto err_ioremap;
	122	}
945478a7	123	dev_set_drvdata(&pdev->dev, res);
ebc915ad MB	124
ebc915ad MB	125	ret = hwrng_register(&omap_rng_ops);
55c381e4 RK	126	if (ret)
55c381e4 RK	127	goto err_register;
ebc915ad	128
af2bc7d2	129	dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
ebc915ad MB	130	omap_rng_read_reg(RNG_REV_REG));
	131	omap_rng_write_reg(RNG_MASK_REG, 0x1);
	132
af2bc7d2	133	rng_dev = pdev;
ebc915ad MB	134
ebc915ad MB	135	return 0;
55c381e4 RK	136
55c381e4 RK	137	err_register:
55c381e4 RK	138	rng_base = NULL;
55c381e4 RK	139	err_ioremap:
55c381e4 RK	140	if (cpu_is_omap24xx()) {
	141	clk_disable(rng_ick);
	142	clk_put(rng_ick);
	143	}
	144	return ret;
ebc915ad MB	145	}
ebc915ad MB	146
af2bc7d2	147	static int __exit omap_rng_remove(struct platform_device *pdev)
ebc915ad	148	{
ebc915ad MB	149	hwrng_unregister(&omap_rng_ops);
	150
	151	omap_rng_write_reg(RNG_MASK_REG, 0x0);
	152
	153	if (cpu_is_omap24xx()) {
af2bc7d2	154	clk_disable(rng_ick);
ebc915ad MB	155	clk_put(rng_ick);
	156	}
	157
ebc915ad MB	158	rng_base = NULL;
	159
	160	return 0;
	161	}
	162
59596df6	163	#ifdef CONFIG_PM_SLEEP
ebc915ad	164
7650572a	165	static int omap_rng_suspend(struct device *dev)
ebc915ad MB	166	{
ebc915ad MB	167	omap_rng_write_reg(RNG_MASK_REG, 0x0);
ebc915ad MB	168	return 0;
	169	}
	170
7650572a	171	static int omap_rng_resume(struct device *dev)
ebc915ad MB	172	{
ebc915ad MB	173	omap_rng_write_reg(RNG_MASK_REG, 0x1);
af2bc7d2	174	return 0;
ebc915ad MB	175	}
ebc915ad MB	176
7650572a RW	177	static SIMPLE_DEV_PM_OPS(omap_rng_pm, omap_rng_suspend, omap_rng_resume);
	178	#define OMAP_RNG_PM (&omap_rng_pm)
	179
ebc915ad MB	180	#else
ebc915ad MB	181
7650572a	182	#define OMAP_RNG_PM NULL
ebc915ad MB	183
	184	#endif
	185
c49a7f18 DB	186	/* work with hotplug and coldplug */
c49a7f18 DB	187	MODULE_ALIAS("platform:omap_rng");
ebc915ad	188
af2bc7d2 DB	189	static struct platform_driver omap_rng_driver = {
	190	.driver = {
	191	.name = "omap_rng",
	192	.owner = THIS_MODULE,
7650572a	193	.pm = OMAP_RNG_PM,
af2bc7d2	194	},
ebc915ad MB	195	.probe = omap_rng_probe,
ebc915ad MB	196	.remove = __exit_p(omap_rng_remove),
ebc915ad MB	197	};
	198
	199	static int __init omap_rng_init(void)
	200	{
	201	if (!cpu_is_omap16xx() && !cpu_is_omap24xx())
	202	return -ENODEV;
	203
af2bc7d2	204	return platform_driver_register(&omap_rng_driver);
ebc915ad MB	205	}
	206
	207	static void __exit omap_rng_exit(void)
	208	{
af2bc7d2	209	platform_driver_unregister(&omap_rng_driver);
ebc915ad MB	210	}
	211
	212	module_init(omap_rng_init);
	213	module_exit(omap_rng_exit);
	214
	215	MODULE_AUTHOR("Deepak Saxena (and others)");
	216	MODULE_LICENSE("GPL");