[linux-2.6-block.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

static struct platform_device *rng_dev;

static int mxc_rnga_data_present(struct hwrng *rng, int wait)
{
	void __iomem *rng_base = (void __iomem *)rng->priv;
	int i;

	for (i = 0; i < 20; i++) {
		/* how many random numbers are in FIFO? [0-16] */
		int level = (__raw_readl(rng_base + 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;
	void __iomem *rng_base = (void __iomem *)rng->priv;

	/* retrieve a random number from FIFO */
	*data = __raw_readl(rng_base + RNGA_OUTPUT_FIFO);

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

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

static int mxc_rnga_init(struct hwrng *rng)
{
	u32 ctrl, osc;
	void __iomem *rng_base = (void __iomem *)rng->priv;

	/* wake up */
	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
	__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, rng_base + RNGA_CONTROL);

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

	/* go running */
	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
	__raw_writel(ctrl | RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);

	return 0;
}

static void mxc_rnga_cleanup(struct hwrng *rng)
{
	u32 ctrl;
	void __iomem *rng_base = (void __iomem *)rng->priv;

	ctrl = __raw_readl(rng_base + RNGA_CONTROL);

	/* stop rnga */
	__raw_writel(ctrl & ~RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
}

static struct hwrng mxc_rnga = {
	.name = "mxc-rnga",
	.init = mxc_rnga_init,
	.cleanup = mxc_rnga_cleanup,
	.data_present = mxc_rnga_data_present,
	.data_read = mxc_rnga_data_read
};

static int __init mxc_rnga_probe(struct platform_device *pdev)
{
	int err = -ENODEV;
	struct clk *clk;
	struct resource *res, *mem;
	void __iomem *rng_base = NULL;

	if (rng_dev)
		return -EBUSY;

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

	clk_enable(clk);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		err = -ENOENT;
		goto err_region;
	}

	mem = request_mem_region(res->start, resource_size(res), pdev->name);
	if (mem == NULL) {
		err = -EBUSY;
		goto err_region;
	}

	rng_base = ioremap(res->start, resource_size(res));
	if (!rng_base) {
		err = -ENOMEM;
		goto err_ioremap;
	}

	mxc_rnga.priv = (unsigned long)rng_base;

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

	rng_dev = pdev;

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

	return 0;

err_register:
	iounmap(rng_base);
	rng_base = NULL;

err_ioremap:
	release_mem_region(res->start, resource_size(res));

err_region:
	clk_disable(clk);
	clk_put(clk);

out:
	return err;
}

static int __exit mxc_rnga_remove(struct platform_device *pdev)
{
	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	void __iomem *rng_base = (void __iomem *)mxc_rnga.priv;
	struct clk *clk = clk_get(&pdev->dev, "rng");

	hwrng_unregister(&mxc_rnga);

	iounmap(rng_base);

	release_mem_region(res->start, resource_size(res));

	clk_disable(clk);
	clk_put(clk);

	return 0;
}

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

static int __init mod_init(void)
{
	return platform_driver_probe(&mxc_rnga_driver, mxc_rnga_probe);
}

static void __exit mod_exit(void)
{
	platform_driver_unregister(&mxc_rnga_driver);
}

module_init(mod_init);
module_exit(mod_exit);

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
	62	static struct platform_device *rng_dev;
	63
36211890	64	static int mxc_rnga_data_present(struct hwrng *rng, int wait)
45001e92	65	{
45001e92	66	void __iomem rng_base = (void __iomem )rng->priv;
36211890 BT	67	int i;
	68
	69	for (i = 0; i < 20; i++) {
	70	/* how many random numbers are in FIFO? [0-16] */
	71	int level = (__raw_readl(rng_base + RNGA_STATUS) &
	72	RNGA_STATUS_LEVEL_MASK) >> 8;
	73	if (level \|\| !wait)
	74	return !!level;
	75	udelay(10);
	76	}
	77	return 0;
45001e92 ACA	78	}
	79
	80	static int mxc_rnga_data_read(struct hwrng rng, u32 data)
	81	{
	82	int err;
	83	u32 ctrl;
	84	void __iomem rng_base = (void __iomem )rng->priv;
	85
	86	/* retrieve a random number from FIFO */
	87	*data = __raw_readl(rng_base + RNGA_OUTPUT_FIFO);
	88
	89	/* some error while reading this random number? */
	90	err = __raw_readl(rng_base + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
	91
	92	/* if error: clear error interrupt, but doesn't return random number */
	93	if (err) {
	94	dev_dbg(&rng_dev->dev, "Error while reading random number!\n");
	95	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
	96	__raw_writel(ctrl \| RNGA_CONTROL_CLEAR_INT,
	97	rng_base + RNGA_CONTROL);
	98	return 0;
	99	} else
	100	return 4;
	101	}
	102
	103	static int mxc_rnga_init(struct hwrng *rng)
	104	{
	105	u32 ctrl, osc;
	106	void __iomem rng_base = (void __iomem )rng->priv;
	107
	108	/* wake up */
	109	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
	110	__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, rng_base + RNGA_CONTROL);
	111
	112	/* verify if oscillator is working */
	113	osc = __raw_readl(rng_base + RNGA_STATUS);
	114	if (osc & RNGA_STATUS_OSC_DEAD) {
	115	dev_err(&rng_dev->dev, "RNGA Oscillator is dead!\n");
	116	return -ENODEV;
	117	}
	118
	119	/* go running */
	120	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
	121	__raw_writel(ctrl \| RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
	122
	123	return 0;
	124	}
	125
	126	static void mxc_rnga_cleanup(struct hwrng *rng)
	127	{
	128	u32 ctrl;
	129	void __iomem rng_base = (void __iomem )rng->priv;
	130
	131	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
	132
	133	/* stop rnga */
	134	__raw_writel(ctrl & ~RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
	135	}
	136
	137	static struct hwrng mxc_rnga = {
	138	.name = "mxc-rnga",
	139	.init = mxc_rnga_init,
	140	.cleanup = mxc_rnga_cleanup,
	141	.data_present = mxc_rnga_data_present,
142	.data_read = mxc_rnga_data_read
143	};
144
145	static int __init mxc_rnga_probe(struct platform_device *pdev)
146	{
147	int err = -ENODEV;
148	struct clk *clk;
149	struct resource res, mem;
150	void __iomem *rng_base = NULL;
151
152	if (rng_dev)
153	return -EBUSY;
154
155	clk = clk_get(&pdev->dev, "rng");
156	if (IS_ERR(clk)) {
157	dev_err(&pdev->dev, "Could not get rng_clk!\n");
158	err = PTR_ERR(clk);
159	goto out;
160	}
161
162	clk_enable(clk);
163
164	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
165	if (!res) {
166	err = -ENOENT;
167	goto err_region;
168	}
169
170	mem = request_mem_region(res->start, resource_size(res), pdev->name);
171	if (mem == NULL) {
172	err = -EBUSY;
173	goto err_region;
174	}
175
176	rng_base = ioremap(res->start, resource_size(res));
177	if (!rng_base) {
178	err = -ENOMEM;
179	goto err_ioremap;
180	}
181
182	mxc_rnga.priv = (unsigned long)rng_base;
183
184	err = hwrng_register(&mxc_rnga);
185	if (err) {
186	dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
187	goto err_register;
188	}
189
190	rng_dev = pdev;
191
192	dev_info(&pdev->dev, "MXC RNGA Registered.\n");
193
194	return 0;
195
196	err_register:
197	iounmap(rng_base);
198	rng_base = NULL;
199
200	err_ioremap:
201	release_mem_region(res->start, resource_size(res));
202
203	err_region:
204	clk_disable(clk);
205	clk_put(clk);
206
207	out:
208	return err;
209	}
210
211	static int __exit mxc_rnga_remove(struct platform_device *pdev)
212	{
213	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
214	void __iomem rng_base = (void __iomem )mxc_rnga.priv;
215	struct clk *clk = clk_get(&pdev->dev, "rng");
216
217	hwrng_unregister(&mxc_rnga);
218
219	iounmap(rng_base);
220
221	release_mem_region(res->start, resource_size(res));
222
223	clk_disable(clk);
224	clk_put(clk);
225
226	return 0;
227	}
228
229	static struct platform_driver mxc_rnga_driver = {
230	.driver = {
231	.name = "mxc_rnga",
232	.owner = THIS_MODULE,
233	},
234	.remove = __exit_p(mxc_rnga_remove),
235	};
236
237	static int __init mod_init(void)
238	{
239	return platform_driver_probe(&mxc_rnga_driver, mxc_rnga_probe);
240	}
241
242	static void __exit mod_exit(void)
243	{
244	platform_driver_unregister(&mxc_rnga_driver);
245	}
246
247	module_init(mod_init);
248	module_exit(mod_exit);
249
250	MODULE_AUTHOR("Freescale Semiconductor, Inc.");
251	MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
252	MODULE_LICENSE("GPL");