[deliverable/linux.git] / drivers / char / hw_random / mxc-rnga.c

/*
 * RNG driver for Freescale RNGA
 *
 * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
 * Author: Alan Carvalho de Assis <acassis@gmail.com>
 */

/*
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 *
 * This driver is based on other RNG drivers.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/ioport.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
#include <linux/delay.h>
#include <linux/io.h>

/* RNGA Registers */
#define RNGA_CONTROL			0x00
#define RNGA_STATUS			0x04
#define RNGA_ENTROPY			0x08
#define RNGA_OUTPUT_FIFO		0x0c
#define RNGA_MODE			0x10
#define RNGA_VERIFICATION_CONTROL	0x14
#define RNGA_OSC_CONTROL_COUNTER	0x18
#define RNGA_OSC1_COUNTER		0x1c
#define RNGA_OSC2_COUNTER		0x20
#define RNGA_OSC_COUNTER_STATUS		0x24

/* RNGA Registers Range */
#define RNG_ADDR_RANGE			0x28

/* RNGA Control Register */
#define RNGA_CONTROL_SLEEP		0x00000010
#define RNGA_CONTROL_CLEAR_INT		0x00000008
#define RNGA_CONTROL_MASK_INTS		0x00000004
#define RNGA_CONTROL_HIGH_ASSURANCE	0x00000002
#define RNGA_CONTROL_GO			0x00000001

#define RNGA_STATUS_LEVEL_MASK		0x0000ff00

/* RNGA Status Register */
#define RNGA_STATUS_OSC_DEAD		0x80000000
#define RNGA_STATUS_SLEEP		0x00000010
#define RNGA_STATUS_ERROR_INT		0x00000008
#define RNGA_STATUS_FIFO_UNDERFLOW	0x00000004
#define RNGA_STATUS_LAST_READ_STATUS	0x00000002
#define RNGA_STATUS_SECURITY_VIOLATION	0x00000001

struct mxc_rng {
	struct device *dev;
	struct hwrng rng;
	void __iomem *mem;
	struct clk *clk;
};

static int mxc_rnga_data_present(struct hwrng *rng, int wait)
{
	int i;
	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

	for (i = 0; i < 20; i++) {
		/* how many random numbers are in FIFO? [0-16] */
		int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) &
				RNGA_STATUS_LEVEL_MASK) >> 8;
		if (level || !wait)
			return !!level;
		udelay(10);
	}
	return 0;
}

static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
{
	int err;
	u32 ctrl;
	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

	/* retrieve a random number from FIFO */
	*data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO);

	/* some error while reading this random number? */
	err = __raw_readl(mxc_rng->mem + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;

	/* if error: clear error interrupt, but doesn't return random number */
	if (err) {
		dev_dbg(mxc_rng->dev, "Error while reading random number!\n");
		ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
		__raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
					mxc_rng->mem + RNGA_CONTROL);
		return 0;
	} else
		return 4;
}

static int mxc_rnga_init(struct hwrng *rng)
{
	u32 ctrl, osc;
	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

	/* wake up */
	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
	__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL);

	/* verify if oscillator is working */
	osc = __raw_readl(mxc_rng->mem + RNGA_STATUS);
	if (osc & RNGA_STATUS_OSC_DEAD) {
		dev_err(mxc_rng->dev, "RNGA Oscillator is dead!\n");
		return -ENODEV;
	}

	/* go running */
	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
	__raw_writel(ctrl | RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);

	return 0;
}

static void mxc_rnga_cleanup(struct hwrng *rng)
{
	u32 ctrl;
	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);

	/* stop rnga */
	__raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
}

static int __init mxc_rnga_probe(struct platform_device *pdev)
{
	int err = -ENODEV;
	struct resource *res;
	struct mxc_rng *mxc_rng;

	mxc_rng = devm_kzalloc(&pdev->dev, sizeof(struct mxc_rng),
					GFP_KERNEL);
	if (!mxc_rng)
		return -ENOMEM;

	mxc_rng->dev = &pdev->dev;
	mxc_rng->rng.name = "mxc-rnga";
	mxc_rng->rng.init = mxc_rnga_init;
	mxc_rng->rng.cleanup = mxc_rnga_cleanup,
	mxc_rng->rng.data_present = mxc_rnga_data_present,
	mxc_rng->rng.data_read = mxc_rnga_data_read,

	mxc_rng->clk = devm_clk_get(&pdev->dev, NULL);
	if (IS_ERR(mxc_rng->clk)) {
		dev_err(&pdev->dev, "Could not get rng_clk!\n");
		err = PTR_ERR(mxc_rng->clk);
		goto out;
	}

	err = clk_prepare_enable(mxc_rng->clk);
	if (err)
		goto out;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	mxc_rng->mem = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(mxc_rng->mem)) {
		err = PTR_ERR(mxc_rng->mem);
		goto err_ioremap;
	}

	err = hwrng_register(&mxc_rng->rng);
	if (err) {
		dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
		goto err_ioremap;
	}

	dev_info(&pdev->dev, "MXC RNGA Registered.\n");

	return 0;

err_ioremap:
	clk_disable_unprepare(mxc_rng->clk);

out:
	return err;
}

static int __exit mxc_rnga_remove(struct platform_device *pdev)
{
	struct mxc_rng *mxc_rng = platform_get_drvdata(pdev);

	hwrng_unregister(&mxc_rng->rng);

	clk_disable_unprepare(mxc_rng->clk);

	return 0;
}

static struct platform_driver mxc_rnga_driver = {
	.driver = {
		   .name = "mxc_rnga",
		   },
	.remove = __exit_p(mxc_rnga_remove),
};

module_platform_driver_probe(mxc_rnga_driver, mxc_rnga_probe);

MODULE_AUTHOR("Freescale Semiconductor, Inc.");
MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
MODULE_LICENSE("GPL");
Commit	Line	Data
45001e92 ACA	1	/*
	2	* RNG driver for Freescale RNGA
	3	*
	4	* Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
	5	* Author: Alan Carvalho de Assis <acassis@gmail.com>
	6	*/
	7
	8	/*
	9	* The code contained herein is licensed under the GNU General Public
	10	* License. You may obtain a copy of the GNU General Public License
	11	* Version 2 or later at the following locations:
	12	*
	13	* http://www.opensource.org/licenses/gpl-license.html
	14	* http://www.gnu.org/copyleft/gpl.html
	15	*
	16	* This driver is based on other RNG drivers.
	17	*/
	18
	19	#include <linux/module.h>
	20	#include <linux/init.h>
	21	#include <linux/kernel.h>
	22	#include <linux/clk.h>
	23	#include <linux/err.h>
	24	#include <linux/ioport.h>
	25	#include <linux/platform_device.h>
	26	#include <linux/hw_random.h>
36211890	27	#include <linux/delay.h>
45001e92 ACA	28	#include <linux/io.h>
	29
	30	/* RNGA Registers */
	31	#define RNGA_CONTROL 0x00
	32	#define RNGA_STATUS 0x04
	33	#define RNGA_ENTROPY 0x08
	34	#define RNGA_OUTPUT_FIFO 0x0c
	35	#define RNGA_MODE 0x10
	36	#define RNGA_VERIFICATION_CONTROL 0x14
	37	#define RNGA_OSC_CONTROL_COUNTER 0x18
	38	#define RNGA_OSC1_COUNTER 0x1c
	39	#define RNGA_OSC2_COUNTER 0x20
	40	#define RNGA_OSC_COUNTER_STATUS 0x24
	41
	42	/* RNGA Registers Range */
	43	#define RNG_ADDR_RANGE 0x28
	44
	45	/* RNGA Control Register */
	46	#define RNGA_CONTROL_SLEEP 0x00000010
	47	#define RNGA_CONTROL_CLEAR_INT 0x00000008
	48	#define RNGA_CONTROL_MASK_INTS 0x00000004
	49	#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
	50	#define RNGA_CONTROL_GO 0x00000001
	51
	52	#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
	53
	54	/* RNGA Status Register */
	55	#define RNGA_STATUS_OSC_DEAD 0x80000000
	56	#define RNGA_STATUS_SLEEP 0x00000010
	57	#define RNGA_STATUS_ERROR_INT 0x00000008
	58	#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
	59	#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
	60	#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
	61
821873ab FE	62	struct mxc_rng {
	63	struct device *dev;
	64	struct hwrng rng;
	65	void __iomem *mem;
	66	struct clk *clk;
	67	};
45001e92	68
36211890	69	static int mxc_rnga_data_present(struct hwrng *rng, int wait)
45001e92	70	{
36211890	71	int i;
821873ab	72	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
36211890 BT	73
	74	for (i = 0; i < 20; i++) {
	75	/* how many random numbers are in FIFO? [0-16] */
821873ab	76	int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) &
36211890 BT	77	RNGA_STATUS_LEVEL_MASK) >> 8;
	78	if (level \|\| !wait)
	79	return !!level;
	80	udelay(10);
	81	}
	82	return 0;
45001e92 ACA	83	}
	84
	85	static int mxc_rnga_data_read(struct hwrng rng, u32 data)
	86	{
	87	int err;
	88	u32 ctrl;
821873ab	89	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
45001e92 ACA	90
45001e92 ACA	91	/* retrieve a random number from FIFO */
821873ab	92	*data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO);
45001e92 ACA	93
45001e92 ACA	94	/* some error while reading this random number? */
821873ab	95	err = __raw_readl(mxc_rng->mem + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
45001e92 ACA	96
	97	/* if error: clear error interrupt, but doesn't return random number */
	98	if (err) {
821873ab FE	99	dev_dbg(mxc_rng->dev, "Error while reading random number!\n");
821873ab FE	100	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
45001e92	101	__raw_writel(ctrl \| RNGA_CONTROL_CLEAR_INT,
821873ab	102	mxc_rng->mem + RNGA_CONTROL);
45001e92 ACA	103	return 0;
	104	} else
	105	return 4;
	106	}
	107
	108	static int mxc_rnga_init(struct hwrng *rng)
	109	{
	110	u32 ctrl, osc;
821873ab	111	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
45001e92 ACA	112
45001e92 ACA	113	/* wake up */
821873ab FE	114	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
821873ab FE	115	__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL);
45001e92 ACA	116
45001e92 ACA	117	/* verify if oscillator is working */
821873ab	118	osc = __raw_readl(mxc_rng->mem + RNGA_STATUS);
45001e92	119	if (osc & RNGA_STATUS_OSC_DEAD) {
821873ab	120	dev_err(mxc_rng->dev, "RNGA Oscillator is dead!\n");
45001e92 ACA	121	return -ENODEV;
	122	}
	123
	124	/* go running */
821873ab FE	125	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
821873ab FE	126	__raw_writel(ctrl \| RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
45001e92 ACA	127
	128	return 0;
	129	}
	130
	131	static void mxc_rnga_cleanup(struct hwrng *rng)
	132	{
	133	u32 ctrl;
821873ab	134	struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);
45001e92	135
821873ab	136	ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
45001e92 ACA	137
45001e92 ACA	138	/* stop rnga */
821873ab	139	__raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);
45001e92 ACA	140	}
45001e92 ACA	141
45001e92 ACA	142	static int __init mxc_rnga_probe(struct platform_device *pdev)
	143	{
	144	int err = -ENODEV;
264878e6	145	struct resource *res;
821873ab FE	146	struct mxc_rng *mxc_rng;
	147
	148	mxc_rng = devm_kzalloc(&pdev->dev, sizeof(struct mxc_rng),
	149	GFP_KERNEL);
	150	if (!mxc_rng)
	151	return -ENOMEM;
	152
	153	mxc_rng->dev = &pdev->dev;
	154	mxc_rng->rng.name = "mxc-rnga";
	155	mxc_rng->rng.init = mxc_rnga_init;
	156	mxc_rng->rng.cleanup = mxc_rnga_cleanup,
	157	mxc_rng->rng.data_present = mxc_rnga_data_present,
	158	mxc_rng->rng.data_read = mxc_rnga_data_read,
	159
	160	mxc_rng->clk = devm_clk_get(&pdev->dev, NULL);
	161	if (IS_ERR(mxc_rng->clk)) {
45001e92	162	dev_err(&pdev->dev, "Could not get rng_clk!\n");
821873ab	163	err = PTR_ERR(mxc_rng->clk);
45001e92 ACA	164	goto out;
	165	}
	166
9e01d0c6 FE	167	err = clk_prepare_enable(mxc_rng->clk);
	168	if (err)
	169	goto out;
45001e92 ACA	170
45001e92 ACA	171	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
264878e6 FE	172	mxc_rng->mem = devm_ioremap_resource(&pdev->dev, res);
	173	if (IS_ERR(mxc_rng->mem)) {
	174	err = PTR_ERR(mxc_rng->mem);
45001e92 ACA	175	goto err_ioremap;
	176	}
	177
821873ab	178	err = hwrng_register(&mxc_rng->rng);
45001e92 ACA	179	if (err) {
45001e92 ACA	180	dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
821873ab	181	goto err_ioremap;
45001e92 ACA	182	}
45001e92 ACA	183
45001e92 ACA	184	dev_info(&pdev->dev, "MXC RNGA Registered.\n");
	185
	186	return 0;
	187
45001e92	188	err_ioremap:
821873ab	189	clk_disable_unprepare(mxc_rng->clk);
45001e92 ACA	190
	191	out:
	192	return err;
	193	}
	194
	195	static int __exit mxc_rnga_remove(struct platform_device *pdev)
	196	{
821873ab	197	struct mxc_rng *mxc_rng = platform_get_drvdata(pdev);
45001e92	198
821873ab	199	hwrng_unregister(&mxc_rng->rng);
45001e92	200
821873ab	201	clk_disable_unprepare(mxc_rng->clk);
45001e92 ACA	202
	203	return 0;
	204	}
	205
	206	static struct platform_driver mxc_rnga_driver = {
	207	.driver = {
	208	.name = "mxc_rnga",
45001e92 ACA	209	},
	210	.remove = __exit_p(mxc_rnga_remove),
	211	};
	212
e7c2199f	213	module_platform_driver_probe(mxc_rnga_driver, mxc_rnga_probe);
45001e92 ACA	214
	215	MODULE_AUTHOR("Freescale Semiconductor, Inc.");
	216	MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
	217	MODULE_LICENSE("GPL");