[mirror_ubuntu-zesty-kernel.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/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 level;
	void __iomem *rng_base = (void __iomem *)rng->priv;

	/* how many random numbers is in FIFO? [0-16] */
	level = ((__raw_readl(rng_base + RNGA_STATUS) &
			RNGA_STATUS_LEVEL_MASK) >> 8);

	return level > 0 ? 1 : 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>
	27	#include <linux/io.h>
	28
	29	/* RNGA Registers */
	30	#define RNGA_CONTROL 0x00
	31	#define RNGA_STATUS 0x04
	32	#define RNGA_ENTROPY 0x08
	33	#define RNGA_OUTPUT_FIFO 0x0c
	34	#define RNGA_MODE 0x10
	35	#define RNGA_VERIFICATION_CONTROL 0x14
	36	#define RNGA_OSC_CONTROL_COUNTER 0x18
	37	#define RNGA_OSC1_COUNTER 0x1c
	38	#define RNGA_OSC2_COUNTER 0x20
	39	#define RNGA_OSC_COUNTER_STATUS 0x24
	40
	41	/* RNGA Registers Range */
	42	#define RNG_ADDR_RANGE 0x28
	43
	44	/* RNGA Control Register */
	45	#define RNGA_CONTROL_SLEEP 0x00000010
	46	#define RNGA_CONTROL_CLEAR_INT 0x00000008
	47	#define RNGA_CONTROL_MASK_INTS 0x00000004
	48	#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
	49	#define RNGA_CONTROL_GO 0x00000001
	50
	51	#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
	52
	53	/* RNGA Status Register */
	54	#define RNGA_STATUS_OSC_DEAD 0x80000000
	55	#define RNGA_STATUS_SLEEP 0x00000010
	56	#define RNGA_STATUS_ERROR_INT 0x00000008
	57	#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
	58	#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
	59	#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
	60
	61	static struct platform_device *rng_dev;
	62
	63	static int mxc_rnga_data_present(struct hwrng *rng)
	64	{
65	int level;
66	void __iomem rng_base = (void __iomem )rng->priv;
67
68	/* how many random numbers is in FIFO? [0-16] */
69	level = ((__raw_readl(rng_base + RNGA_STATUS) &
70	RNGA_STATUS_LEVEL_MASK) >> 8);
71
72	return level > 0 ? 1 : 0;
73	}
74
75	static int mxc_rnga_data_read(struct hwrng rng, u32 data)
76	{
77	int err;
78	u32 ctrl;
79	void __iomem rng_base = (void __iomem )rng->priv;
80
81	/* retrieve a random number from FIFO */
82	*data = __raw_readl(rng_base + RNGA_OUTPUT_FIFO);
83
84	/* some error while reading this random number? */
85	err = __raw_readl(rng_base + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
86
87	/* if error: clear error interrupt, but doesn't return random number */
88	if (err) {
89	dev_dbg(&rng_dev->dev, "Error while reading random number!\n");
90	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
91	__raw_writel(ctrl \| RNGA_CONTROL_CLEAR_INT,
92	rng_base + RNGA_CONTROL);
93	return 0;
94	} else
95	return 4;
96	}
97
98	static int mxc_rnga_init(struct hwrng *rng)
99	{
100	u32 ctrl, osc;
101	void __iomem rng_base = (void __iomem )rng->priv;
102
103	/* wake up */
104	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
105	__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, rng_base + RNGA_CONTROL);
106
107	/* verify if oscillator is working */
108	osc = __raw_readl(rng_base + RNGA_STATUS);
109	if (osc & RNGA_STATUS_OSC_DEAD) {
110	dev_err(&rng_dev->dev, "RNGA Oscillator is dead!\n");
111	return -ENODEV;
112	}
113
114	/* go running */
115	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
116	__raw_writel(ctrl \| RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
117
118	return 0;
119	}
120
121	static void mxc_rnga_cleanup(struct hwrng *rng)
122	{
123	u32 ctrl;
124	void __iomem rng_base = (void __iomem )rng->priv;
125
126	ctrl = __raw_readl(rng_base + RNGA_CONTROL);
127
128	/* stop rnga */
129	__raw_writel(ctrl & ~RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
130	}
131
132	static struct hwrng mxc_rnga = {
133	.name = "mxc-rnga",
134	.init = mxc_rnga_init,
135	.cleanup = mxc_rnga_cleanup,
136	.data_present = mxc_rnga_data_present,
137	.data_read = mxc_rnga_data_read
138	};
139
140	static int __init mxc_rnga_probe(struct platform_device *pdev)
141	{
142	int err = -ENODEV;
143	struct clk *clk;
144	struct resource res, mem;
145	void __iomem *rng_base = NULL;
146
147	if (rng_dev)
148	return -EBUSY;
149
150	clk = clk_get(&pdev->dev, "rng");
151	if (IS_ERR(clk)) {
152	dev_err(&pdev->dev, "Could not get rng_clk!\n");
153	err = PTR_ERR(clk);
154	goto out;
155	}
156
157	clk_enable(clk);
158
159	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
160	if (!res) {
161	err = -ENOENT;
162	goto err_region;
163	}
164
165	mem = request_mem_region(res->start, resource_size(res), pdev->name);
166	if (mem == NULL) {
167	err = -EBUSY;
168	goto err_region;
169	}
170
171	rng_base = ioremap(res->start, resource_size(res));
172	if (!rng_base) {
173	err = -ENOMEM;
174	goto err_ioremap;
175	}
176
177	mxc_rnga.priv = (unsigned long)rng_base;
178
179	err = hwrng_register(&mxc_rnga);
180	if (err) {
181	dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
182	goto err_register;
183	}
184
185	rng_dev = pdev;
186
187	dev_info(&pdev->dev, "MXC RNGA Registered.\n");
188
189	return 0;
190
191	err_register:
192	iounmap(rng_base);
193	rng_base = NULL;
194
195	err_ioremap:
196	release_mem_region(res->start, resource_size(res));
197
198	err_region:
199	clk_disable(clk);
200	clk_put(clk);
201
202	out:
203	return err;
204	}
205
206	static int __exit mxc_rnga_remove(struct platform_device *pdev)
207	{
208	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
209	void __iomem rng_base = (void __iomem )mxc_rnga.priv;
210	struct clk *clk = clk_get(&pdev->dev, "rng");
211
212	hwrng_unregister(&mxc_rnga);
213
214	iounmap(rng_base);
215
216	release_mem_region(res->start, resource_size(res));
217
218	clk_disable(clk);
219	clk_put(clk);
220
221	return 0;
222	}
223
224	static struct platform_driver mxc_rnga_driver = {
225	.driver = {
226	.name = "mxc_rnga",
227	.owner = THIS_MODULE,
228	},
229	.remove = __exit_p(mxc_rnga_remove),
230	};
231
232	static int __init mod_init(void)
233	{
234	return platform_driver_probe(&mxc_rnga_driver, mxc_rnga_probe);
235	}
236
237	static void __exit mod_exit(void)
238	{
239	platform_driver_unregister(&mxc_rnga_driver);
240	}
241
242	module_init(mod_init);
243	module_exit(mod_exit);
244
245	MODULE_AUTHOR("Freescale Semiconductor, Inc.");
246	MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
247	MODULE_LICENSE("GPL");