[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_address.h>
#include <linux/of_platform.h>
#include <linux/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 rng_probe(struct platform_device *pdev)
{
	void __iomem *rng_regs;
	struct resource *res;

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

	pasemi_rng.priv = (unsigned long)rng_regs;

	pr_info("Registering PA Semi RNG\n");
	return devm_hwrng_register(&pdev->dev, &pasemi_rng);
}

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

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

module_platform_driver(rng_driver);

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>
5af50730	27	#include <linux/of_address.h>
98cad101	28	#include <linux/of_platform.h>
a826806b	29	#include <linux/io.h>
b8cb3448 OJ	30
	31	#define SDCRNG_CTL_REG 0x00
	32	#define SDCRNG_CTL_FVLD_M 0x0000f000
	33	#define SDCRNG_CTL_FVLD_S 12
	34	#define SDCRNG_CTL_KSZ 0x00000800
	35	#define SDCRNG_CTL_RSRC_CRG 0x00000010
	36	#define SDCRNG_CTL_RSRC_RRG 0x00000000
	37	#define SDCRNG_CTL_CE 0x00000004
	38	#define SDCRNG_CTL_RE 0x00000002
	39	#define SDCRNG_CTL_DR 0x00000001
	40	#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE \| SDCRNG_CTL_RSRC_RRG)
	41	#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE \| SDCRNG_CTL_RSRC_CRG)
	42	#define SDCRNG_VAL_REG 0x20
	43
	44	#define MODULE_NAME "pasemi_rng"
	45
9aa6ad3e	46	static int pasemi_rng_data_present(struct hwrng *rng, int wait)
b8cb3448 OJ	47	{
b8cb3448 OJ	48	void __iomem rng_regs = (void __iomem )rng->priv;
984e976f	49	int data, i;
b8cb3448	50
984e976f PM	51	for (i = 0; i < 20; i++) {
	52	data = (in_le32(rng_regs + SDCRNG_CTL_REG)
	53	& SDCRNG_CTL_FVLD_M) ? 1 : 0;
	54	if (data \|\| !wait)
	55	break;
	56	udelay(10);
	57	}
	58	return data;
b8cb3448 OJ	59	}
	60
	61	static int pasemi_rng_data_read(struct hwrng rng, u32 data)
	62	{
	63	void __iomem rng_regs = (void __iomem )rng->priv;
	64	*data = in_le32(rng_regs + SDCRNG_VAL_REG);
	65	return 4;
	66	}
	67
	68	static int pasemi_rng_init(struct hwrng *rng)
	69	{
	70	void __iomem rng_regs = (void __iomem )rng->priv;
	71	u32 ctl;
	72
	73	ctl = SDCRNG_CTL_DR \| SDCRNG_CTL_SELECT_RRG_RNG \| SDCRNG_CTL_KSZ;
	74	out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
	75	out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
	76
	77	return 0;
	78	}
	79
	80	static void pasemi_rng_cleanup(struct hwrng *rng)
	81	{
	82	void __iomem rng_regs = (void __iomem )rng->priv;
	83	u32 ctl;
	84
	85	ctl = SDCRNG_CTL_RE \| SDCRNG_CTL_CE;
	86	out_le32(rng_regs + SDCRNG_CTL_REG,
	87	in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
	88	}
	89
	90	static struct hwrng pasemi_rng = {
	91	.name = MODULE_NAME,
	92	.init = pasemi_rng_init,
	93	.cleanup = pasemi_rng_cleanup,
	94	.data_present = pasemi_rng_data_present,
	95	.data_read = pasemi_rng_data_read,
	96	};
	97
da28caaa	98	static int rng_probe(struct platform_device *pdev)
b8cb3448 OJ	99	{
b8cb3448 OJ	100	void __iomem *rng_regs;
da28caaa	101	struct resource *res;
b8cb3448	102
da28caaa PM	103	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	104	rng_regs = devm_ioremap_resource(&pdev->dev, res);
	105	if (IS_ERR(rng_regs))
	106	return PTR_ERR(rng_regs);
b8cb3448 OJ	107
	108	pasemi_rng.priv = (unsigned long)rng_regs;
	109
7a1ae9c0	110	pr_info("Registering PA Semi RNG\n");
da28caaa	111	return devm_hwrng_register(&pdev->dev, &pasemi_rng);
b8cb3448 OJ	112	}
b8cb3448 OJ	113
da2ff527	114	static const struct of_device_id rng_match[] = {
0d08a847 OJ	115	{ .compatible = "1682m-rng", },
	116	{ .compatible = "pasemi,pwrficient-rng", },
	117	{ },
b8cb3448	118	};
5f8741d1	119	MODULE_DEVICE_TABLE(of, rng_match);
b8cb3448	120
00006124	121	static struct platform_driver rng_driver = {
4018294b GL	122	.driver = {
4018294b GL	123	.name = "pasemi-rng",
4018294b GL	124	.of_match_table = rng_match,
4018294b GL	125	},
b8cb3448	126	.probe = rng_probe,
b8cb3448 OJ	127	};
b8cb3448 OJ	128
b21cb324	129	module_platform_driver(rng_driver);
b8cb3448 OJ	130
	131	MODULE_LICENSE("GPL");
	132	MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
	133	MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");