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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2006-2007 PA Semi, Inc
 *
 * Maintained by: Olof Johansson <olof@lixom.net>
 *
 * Driver for the PWRficient onchip rng
 */

#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
45051539	1	// SPDX-License-Identifier: GPL-2.0-only
b8cb3448 OJ	2	/*
	3	* Copyright (C) 2006-2007 PA Semi, Inc
	4	*
	5	* Maintained by: Olof Johansson <olof@lixom.net>
	6	*
	7	* Driver for the PWRficient onchip rng
b8cb3448 OJ	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/kernel.h>
	12	#include <linux/platform_device.h>
	13	#include <linux/hw_random.h>
984e976f	14	#include <linux/delay.h>
5af50730	15	#include <linux/of_address.h>
98cad101	16	#include <linux/of_platform.h>
a826806b	17	#include <linux/io.h>
b8cb3448 OJ	18
	19	#define SDCRNG_CTL_REG 0x00
	20	#define SDCRNG_CTL_FVLD_M 0x0000f000
	21	#define SDCRNG_CTL_FVLD_S 12
	22	#define SDCRNG_CTL_KSZ 0x00000800
	23	#define SDCRNG_CTL_RSRC_CRG 0x00000010
	24	#define SDCRNG_CTL_RSRC_RRG 0x00000000
	25	#define SDCRNG_CTL_CE 0x00000004
	26	#define SDCRNG_CTL_RE 0x00000002
	27	#define SDCRNG_CTL_DR 0x00000001
	28	#define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE \| SDCRNG_CTL_RSRC_RRG)
	29	#define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE \| SDCRNG_CTL_RSRC_CRG)
	30	#define SDCRNG_VAL_REG 0x20
	31
	32	#define MODULE_NAME "pasemi_rng"
	33
9aa6ad3e	34	static int pasemi_rng_data_present(struct hwrng *rng, int wait)
b8cb3448 OJ	35	{
b8cb3448 OJ	36	void __iomem rng_regs = (void __iomem )rng->priv;
984e976f	37	int data, i;
b8cb3448	38
984e976f PM	39	for (i = 0; i < 20; i++) {
	40	data = (in_le32(rng_regs + SDCRNG_CTL_REG)
	41	& SDCRNG_CTL_FVLD_M) ? 1 : 0;
	42	if (data \|\| !wait)
	43	break;
	44	udelay(10);
	45	}
	46	return data;
b8cb3448 OJ	47	}
	48
	49	static int pasemi_rng_data_read(struct hwrng rng, u32 data)
	50	{
	51	void __iomem rng_regs = (void __iomem )rng->priv;
	52	*data = in_le32(rng_regs + SDCRNG_VAL_REG);
	53	return 4;
	54	}
	55
	56	static int pasemi_rng_init(struct hwrng *rng)
	57	{
	58	void __iomem rng_regs = (void __iomem )rng->priv;
	59	u32 ctl;
	60
	61	ctl = SDCRNG_CTL_DR \| SDCRNG_CTL_SELECT_RRG_RNG \| SDCRNG_CTL_KSZ;
	62	out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
	63	out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
	64
	65	return 0;
	66	}
	67
	68	static void pasemi_rng_cleanup(struct hwrng *rng)
	69	{
	70	void __iomem rng_regs = (void __iomem )rng->priv;
	71	u32 ctl;
	72
	73	ctl = SDCRNG_CTL_RE \| SDCRNG_CTL_CE;
	74	out_le32(rng_regs + SDCRNG_CTL_REG,
	75	in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
	76	}
	77
	78	static struct hwrng pasemi_rng = {
	79	.name = MODULE_NAME,
	80	.init = pasemi_rng_init,
	81	.cleanup = pasemi_rng_cleanup,
	82	.data_present = pasemi_rng_data_present,
	83	.data_read = pasemi_rng_data_read,
	84	};
	85
da28caaa	86	static int rng_probe(struct platform_device *pdev)
b8cb3448 OJ	87	{
b8cb3448 OJ	88	void __iomem *rng_regs;
da28caaa	89	struct resource *res;
b8cb3448	90
da28caaa PM	91	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	92	rng_regs = devm_ioremap_resource(&pdev->dev, res);
	93	if (IS_ERR(rng_regs))
	94	return PTR_ERR(rng_regs);
b8cb3448 OJ	95
	96	pasemi_rng.priv = (unsigned long)rng_regs;
	97
7a1ae9c0	98	pr_info("Registering PA Semi RNG\n");
da28caaa	99	return devm_hwrng_register(&pdev->dev, &pasemi_rng);
b8cb3448 OJ	100	}
b8cb3448 OJ	101
da2ff527	102	static const struct of_device_id rng_match[] = {
0d08a847 OJ	103	{ .compatible = "1682m-rng", },
	104	{ .compatible = "pasemi,pwrficient-rng", },
	105	{ },
b8cb3448	106	};
5f8741d1	107	MODULE_DEVICE_TABLE(of, rng_match);
b8cb3448	108
00006124	109	static struct platform_driver rng_driver = {
4018294b GL	110	.driver = {
4018294b GL	111	.name = "pasemi-rng",
4018294b GL	112	.of_match_table = rng_match,
4018294b GL	113	},
b8cb3448	114	.probe = rng_probe,
b8cb3448 OJ	115	};
b8cb3448 OJ	116
b21cb324	117	module_platform_driver(rng_driver);
b8cb3448 OJ	118
	119	MODULE_LICENSE("GPL");
	120	MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
	121	MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");