[mirror_ubuntu-zesty-kernel.git] / drivers / char / hw_random / pasemi-rng.c

/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Maintained by: Olof Johansson <olof@lixom.net>
 *
 * Driver for the PWRficient onchip rng
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 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/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
#include <linux/delay.h>
#include <linux/of_platform.h>
#include <asm/io.h>

#define SDCRNG_CTL_REG			0x00
#define   SDCRNG_CTL_FVLD_M		0x0000f000
#define   SDCRNG_CTL_FVLD_S		12
#define   SDCRNG_CTL_KSZ		0x00000800
#define   SDCRNG_CTL_RSRC_CRG		0x00000010
#define   SDCRNG_CTL_RSRC_RRG		0x00000000
#define   SDCRNG_CTL_CE			0x00000004
#define   SDCRNG_CTL_RE			0x00000002
#define   SDCRNG_CTL_DR			0x00000001
#define   SDCRNG_CTL_SELECT_RRG_RNG	(SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG)
#define   SDCRNG_CTL_SELECT_CRG_RNG	(SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG)
#define SDCRNG_VAL_REG			0x20

#define MODULE_NAME "pasemi_rng"

static int pasemi_rng_data_present(struct hwrng *rng, int wait)
{
	void __iomem *rng_regs = (void __iomem *)rng->priv;
	int data, i;

	for (i = 0; i < 20; i++) {
		data = (in_le32(rng_regs + SDCRNG_CTL_REG)
			& SDCRNG_CTL_FVLD_M) ? 1 : 0;
		if (data || !wait)
			break;
		udelay(10);
	}
	return data;
}

static int pasemi_rng_data_read(struct hwrng *rng, u32 *data)
{
	void __iomem *rng_regs = (void __iomem *)rng->priv;
	*data = in_le32(rng_regs + SDCRNG_VAL_REG);
	return 4;
}

static int pasemi_rng_init(struct hwrng *rng)
{
	void __iomem *rng_regs = (void __iomem *)rng->priv;
	u32 ctl;

	ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ;
	out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
	out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);

	return 0;
}

static void pasemi_rng_cleanup(struct hwrng *rng)
{
	void __iomem *rng_regs = (void __iomem *)rng->priv;
	u32 ctl;

	ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE;
	out_le32(rng_regs + SDCRNG_CTL_REG,
		 in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
}

static struct hwrng pasemi_rng = {
	.name		= MODULE_NAME,
	.init		= pasemi_rng_init,
	.cleanup	= pasemi_rng_cleanup,
	.data_present	= pasemi_rng_data_present,
	.data_read	= pasemi_rng_data_read,
};

static int __devinit rng_probe(struct platform_device *ofdev)
{
	void __iomem *rng_regs;
	struct device_node *rng_np = ofdev->dev.of_node;
	struct resource res;
	int err = 0;

	err = of_address_to_resource(rng_np, 0, &res);
	if (err)
		return -ENODEV;

	rng_regs = ioremap(res.start, 0x100);

	if (!rng_regs)
		return -ENOMEM;

	pasemi_rng.priv = (unsigned long)rng_regs;

	printk(KERN_INFO "Registering PA Semi RNG\n");

	err = hwrng_register(&pasemi_rng);

	if (err)
		iounmap(rng_regs);

	return err;
}

static int __devexit rng_remove(struct platform_device *dev)
{
	void __iomem *rng_regs = (void __iomem *)pasemi_rng.priv;

	hwrng_unregister(&pasemi_rng);
	iounmap(rng_regs);

	return 0;
}

static struct of_device_id rng_match[] = {
	{ .compatible      = "1682m-rng", },
	{ .compatible      = "pasemi,pwrficient-rng", },
	{ },
};

static struct platform_driver rng_driver = {
	.driver = {
		.name = "pasemi-rng",
		.owner = THIS_MODULE,
		.of_match_table = rng_match,
	},
	.probe		= rng_probe,
	.remove		= rng_remove,
};

static int __init rng_init(void)
{
	return platform_driver_register(&rng_driver);
}
module_init(rng_init);

static void __exit rng_exit(void)
{
	platform_driver_unregister(&rng_driver);
}
module_exit(rng_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");
Commit	Line	Data
b8cb3448 OJ	1	/*
	2	* Copyright (C) 2006-2007 PA Semi, Inc
	3	*
	4	* Maintained by: Olof Johansson <olof@lixom.net>
	5	*
	6	* Driver for the PWRficient onchip rng
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*
	12	* This program is distributed in the hope that it will be useful,
	13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	* GNU General Public License for more details.
	16	*
	17	* You should have received a copy of the GNU General Public License
	18	* along with this program; if not, write to the Free Software
	19	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	20	*/
	21
	22	#include <linux/module.h>
	23	#include <linux/kernel.h>
	24	#include <linux/platform_device.h>
	25	#include <linux/hw_random.h>
984e976f	26	#include <linux/delay.h>
98cad101	27	#include <linux/of_platform.h>
b8cb3448 OJ	28	#include <asm/io.h>
	29
	30	#define SDCRNG_CTL_REG 0x00
	31	#define SDCRNG_CTL_FVLD_M 0x0000f000
	32	#define SDCRNG_CTL_FVLD_S 12
	33	#define SDCRNG_CTL_KSZ 0x00000800
	34	#define SDCRNG_CTL_RSRC_CRG 0x00000010
	35	#define SDCRNG_CTL_RSRC_RRG 0x00000000
	36	#define SDCRNG_CTL_CE 0x00000004
	37	#define SDCRNG_CTL_RE 0x00000002
	38	#define SDCRNG_CTL_DR 0x00000001
	39	#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE \| SDCRNG_CTL_RSRC_RRG)
	40	#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE \| SDCRNG_CTL_RSRC_CRG)
	41	#define SDCRNG_VAL_REG 0x20
	42
	43	#define MODULE_NAME "pasemi_rng"
	44
9aa6ad3e	45	static int pasemi_rng_data_present(struct hwrng *rng, int wait)
b8cb3448 OJ	46	{
b8cb3448 OJ	47	void __iomem rng_regs = (void __iomem )rng->priv;
984e976f	48	int data, i;
b8cb3448	49
984e976f PM	50	for (i = 0; i < 20; i++) {
	51	data = (in_le32(rng_regs + SDCRNG_CTL_REG)
	52	& SDCRNG_CTL_FVLD_M) ? 1 : 0;
	53	if (data \|\| !wait)
	54	break;
	55	udelay(10);
	56	}
	57	return data;
b8cb3448 OJ	58	}
	59
	60	static int pasemi_rng_data_read(struct hwrng rng, u32 data)
	61	{
	62	void __iomem rng_regs = (void __iomem )rng->priv;
	63	*data = in_le32(rng_regs + SDCRNG_VAL_REG);
	64	return 4;
	65	}
	66
	67	static int pasemi_rng_init(struct hwrng *rng)
	68	{
	69	void __iomem rng_regs = (void __iomem )rng->priv;
	70	u32 ctl;
	71
	72	ctl = SDCRNG_CTL_DR \| SDCRNG_CTL_SELECT_RRG_RNG \| SDCRNG_CTL_KSZ;
	73	out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
	74	out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
	75
	76	return 0;
	77	}
	78
	79	static void pasemi_rng_cleanup(struct hwrng *rng)
	80	{
	81	void __iomem rng_regs = (void __iomem )rng->priv;
	82	u32 ctl;
	83
	84	ctl = SDCRNG_CTL_RE \| SDCRNG_CTL_CE;
	85	out_le32(rng_regs + SDCRNG_CTL_REG,
	86	in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
	87	}
	88
	89	static struct hwrng pasemi_rng = {
	90	.name = MODULE_NAME,
	91	.init = pasemi_rng_init,
	92	.cleanup = pasemi_rng_cleanup,
	93	.data_present = pasemi_rng_data_present,
	94	.data_read = pasemi_rng_data_read,
	95	};
	96
00006124	97	static int __devinit rng_probe(struct platform_device *ofdev)
b8cb3448 OJ	98	{
b8cb3448 OJ	99	void __iomem *rng_regs;
61c7a080	100	struct device_node *rng_np = ofdev->dev.of_node;
b8cb3448 OJ	101	struct resource res;
	102	int err = 0;
	103
	104	err = of_address_to_resource(rng_np, 0, &res);
	105	if (err)
	106	return -ENODEV;
	107
	108	rng_regs = ioremap(res.start, 0x100);
	109
	110	if (!rng_regs)
	111	return -ENOMEM;
	112
	113	pasemi_rng.priv = (unsigned long)rng_regs;
	114
	115	printk(KERN_INFO "Registering PA Semi RNG\n");
	116
	117	err = hwrng_register(&pasemi_rng);
	118
	119	if (err)
	120	iounmap(rng_regs);
	121
	122	return err;
	123	}
	124
2dc11581	125	static int __devexit rng_remove(struct platform_device *dev)
b8cb3448 OJ	126	{
	127	void __iomem rng_regs = (void __iomem )pasemi_rng.priv;
	128
	129	hwrng_unregister(&pasemi_rng);
	130	iounmap(rng_regs);
	131
	132	return 0;
	133	}
	134
	135	static struct of_device_id rng_match[] = {
0d08a847 OJ	136	{ .compatible = "1682m-rng", },
	137	{ .compatible = "pasemi,pwrficient-rng", },
	138	{ },
b8cb3448 OJ	139	};
b8cb3448 OJ	140
00006124	141	static struct platform_driver rng_driver = {
4018294b GL	142	.driver = {
	143	.name = "pasemi-rng",
	144	.owner = THIS_MODULE,
	145	.of_match_table = rng_match,
	146	},
b8cb3448 OJ	147	.probe = rng_probe,
	148	.remove = rng_remove,
	149	};
	150
	151	static int __init rng_init(void)
	152	{
00006124	153	return platform_driver_register(&rng_driver);
b8cb3448 OJ	154	}
	155	module_init(rng_init);
	156
	157	static void __exit rng_exit(void)
	158	{
00006124	159	platform_driver_unregister(&rng_driver);
b8cb3448 OJ	160	}
	161	module_exit(rng_exit);
	162
	163	MODULE_LICENSE("GPL");
	164	MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
	165	MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");