[deliverable/linux.git] / drivers / char / hw_random / bcm2835-rng.c

/**
 * Copyright (c) 2010-2012 Broadcom. All rights reserved.
 * Copyright (c) 2013 Lubomir Rintel
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License ("GPL")
 * version 2, as published by the Free Software Foundation.
 */

#include <linux/hw_random.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/printk.h>

#define RNG_CTRL	0x0
#define RNG_STATUS	0x4
#define RNG_DATA	0x8
#define RNG_INT_MASK	0x10

/* enable rng */
#define RNG_RBGEN	0x1

/* the initial numbers generated are "less random" so will be discarded */
#define RNG_WARMUP_COUNT 0x40000

#define RNG_INT_OFF	0x1

static void __init nsp_rng_init(void __iomem *base)
{
	u32 val;

	/* mask the interrupt */
	val = readl(base + RNG_INT_MASK);
	val |= RNG_INT_OFF;
	writel(val, base + RNG_INT_MASK);
}

static int bcm2835_rng_read(struct hwrng *rng, void *buf, size_t max,
			       bool wait)
{
	void __iomem *rng_base = (void __iomem *)rng->priv;
	u32 max_words = max / sizeof(u32);
	u32 num_words, count;

	while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) {
		if (!wait)
			return 0;
		cpu_relax();
	}

	num_words = readl(rng_base + RNG_STATUS) >> 24;
	if (num_words > max_words)
		num_words = max_words;

	for (count = 0; count < num_words; count++)
		((u32 *)buf)[count] = readl(rng_base + RNG_DATA);

	return num_words * sizeof(u32);
}

static struct hwrng bcm2835_rng_ops = {
	.name	= "bcm2835",
	.read	= bcm2835_rng_read,
};

static const struct of_device_id bcm2835_rng_of_match[] = {
	{ .compatible = "brcm,bcm2835-rng"},
	{ .compatible = "brcm,bcm-nsp-rng", .data = nsp_rng_init},
	{},
};

static int bcm2835_rng_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	void (*rng_setup)(void __iomem *base);
	const struct of_device_id *rng_id;
	void __iomem *rng_base;
	int err;

	/* map peripheral */
	rng_base = of_iomap(np, 0);
	if (!rng_base) {
		dev_err(dev, "failed to remap rng regs");
		return -ENODEV;
	}
	bcm2835_rng_ops.priv = (unsigned long)rng_base;

	rng_id = of_match_node(bcm2835_rng_of_match, np);
	if (!rng_id)
		return -EINVAL;

	/* Check for rng init function, execute it */
	rng_setup = rng_id->data;
	if (rng_setup)
		rng_setup(rng_base);

	/* set warm-up count & enable */
	__raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
	__raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);

	/* register driver */
	err = hwrng_register(&bcm2835_rng_ops);
	if (err) {
		dev_err(dev, "hwrng registration failed\n");
		iounmap(rng_base);
	} else
		dev_info(dev, "hwrng registered\n");

	return err;
}

static int bcm2835_rng_remove(struct platform_device *pdev)
{
	void __iomem *rng_base = (void __iomem *)bcm2835_rng_ops.priv;

	/* disable rng hardware */
	__raw_writel(0, rng_base + RNG_CTRL);

	/* unregister driver */
	hwrng_unregister(&bcm2835_rng_ops);
	iounmap(rng_base);

	return 0;
}

MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);

static struct platform_driver bcm2835_rng_driver = {
	.driver = {
		.name = "bcm2835-rng",
		.of_match_table = bcm2835_rng_of_match,
	},
	.probe		= bcm2835_rng_probe,
	.remove		= bcm2835_rng_remove,
};
module_platform_driver(bcm2835_rng_driver);

MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
8c4196a2 LR	1	/**
	2	* Copyright (c) 2010-2012 Broadcom. All rights reserved.
	3	* Copyright (c) 2013 Lubomir Rintel
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License ("GPL")
	7	* version 2, as published by the Free Software Foundation.
	8	*/
	9
	10	#include <linux/hw_random.h>
8c4196a2 LR	11	#include <linux/io.h>
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/of_address.h>
	15	#include <linux/of_platform.h>
	16	#include <linux/platform_device.h>
	17	#include <linux/printk.h>
	18
	19	#define RNG_CTRL 0x0
	20	#define RNG_STATUS 0x4
	21	#define RNG_DATA 0x8
422a7491	22	#define RNG_INT_MASK 0x10
8c4196a2 LR	23
	24	/* enable rng */
	25	#define RNG_RBGEN 0x1
	26
	27	/* the initial numbers generated are "less random" so will be discarded */
	28	#define RNG_WARMUP_COUNT 0x40000
	29
422a7491 YRDR	30	#define RNG_INT_OFF 0x1
	31
	32	static void __init nsp_rng_init(void __iomem *base)
	33	{
	34	u32 val;
	35
	36	/* mask the interrupt */
	37	val = readl(base + RNG_INT_MASK);
	38	val \|= RNG_INT_OFF;
	39	writel(val, base + RNG_INT_MASK);
	40	}
	41
8c4196a2 LR	42	static int bcm2835_rng_read(struct hwrng rng, void buf, size_t max,
	43	bool wait)
	44	{
	45	void __iomem rng_base = (void __iomem )rng->priv;
4f8de65b YRDR	46	u32 max_words = max / sizeof(u32);
4f8de65b YRDR	47	u32 num_words, count;
8c4196a2 LR	48
	49	while ((__raw_readl(rng_base + RNG_STATUS) >> 24) == 0) {
	50	if (!wait)
	51	return 0;
	52	cpu_relax();
	53	}
	54
4f8de65b YRDR	55	num_words = readl(rng_base + RNG_STATUS) >> 24;
	56	if (num_words > max_words)
	57	num_words = max_words;
	58
	59	for (count = 0; count < num_words; count++)
	60	((u32 *)buf)[count] = readl(rng_base + RNG_DATA);
	61
	62	return num_words * sizeof(u32);
8c4196a2 LR	63	}
	64
	65	static struct hwrng bcm2835_rng_ops = {
	66	.name = "bcm2835",
	67	.read = bcm2835_rng_read,
	68	};
	69
422a7491 YRDR	70	static const struct of_device_id bcm2835_rng_of_match[] = {
	71	{ .compatible = "brcm,bcm2835-rng"},
	72	{ .compatible = "brcm,bcm-nsp-rng", .data = nsp_rng_init},
	73	{},
	74	};
	75
8c4196a2 LR	76	static int bcm2835_rng_probe(struct platform_device *pdev)
	77	{
	78	struct device *dev = &pdev->dev;
	79	struct device_node *np = dev->of_node;
422a7491 YRDR	80	void (rng_setup)(void __iomem base);
422a7491 YRDR	81	const struct of_device_id *rng_id;
8c4196a2 LR	82	void __iomem *rng_base;
	83	int err;
	84
	85	/* map peripheral */
	86	rng_base = of_iomap(np, 0);
	87	if (!rng_base) {
	88	dev_err(dev, "failed to remap rng regs");
	89	return -ENODEV;
	90	}
	91	bcm2835_rng_ops.priv = (unsigned long)rng_base;
	92
422a7491 YRDR	93	rng_id = of_match_node(bcm2835_rng_of_match, np);
	94	if (!rng_id)
	95	return -EINVAL;
	96
	97	/* Check for rng init function, execute it */
	98	rng_setup = rng_id->data;
	99	if (rng_setup)
	100	rng_setup(rng_base);
	101
eb4a5346 MP	102	/* set warm-up count & enable */
	103	__raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
	104	__raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
	105
8c4196a2 LR	106	/* register driver */
	107	err = hwrng_register(&bcm2835_rng_ops);
	108	if (err) {
	109	dev_err(dev, "hwrng registration failed\n");
	110	iounmap(rng_base);
eb4a5346	111	} else
8c4196a2 LR	112	dev_info(dev, "hwrng registered\n");
8c4196a2 LR	113
8c4196a2 LR	114	return err;
	115	}
	116
	117	static int bcm2835_rng_remove(struct platform_device *pdev)
	118	{
	119	void __iomem rng_base = (void __iomem )bcm2835_rng_ops.priv;
	120
	121	/* disable rng hardware */
	122	__raw_writel(0, rng_base + RNG_CTRL);
	123
	124	/* unregister driver */
	125	hwrng_unregister(&bcm2835_rng_ops);
	126	iounmap(rng_base);
	127
	128	return 0;
	129	}
	130
8c4196a2 LR	131	MODULE_DEVICE_TABLE(of, bcm2835_rng_of_match);
	132
	133	static struct platform_driver bcm2835_rng_driver = {
	134	.driver = {
	135	.name = "bcm2835-rng",
8c4196a2 LR	136	.of_match_table = bcm2835_rng_of_match,
	137	},
	138	.probe = bcm2835_rng_probe,
	139	.remove = bcm2835_rng_remove,
	140	};
	141	module_platform_driver(bcm2835_rng_driver);
	142
	143	MODULE_AUTHOR("Lubomir Rintel <lkundrak@v3.sk>");
	144	MODULE_DESCRIPTION("BCM2835 Random Number Generator (RNG) driver");
22e8099f	145	MODULE_LICENSE("GPL v2");