[linux-2.6-block.git] / drivers / watchdog / ath79_wdt.c

/*
 * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
 *
 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
 *
 * This driver was based on: drivers/watchdog/ixp4xx_wdt.c
 *	Author: Deepak Saxena <dsaxena@plexity.net>
 *	Copyright 2004 (c) MontaVista, Software, Inc.
 *
 * which again was based on sa1100 driver,
 *	Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 *
 */

#include <linux/bitops.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/types.h>
#include <linux/watchdog.h>
#include <linux/clk.h>
#include <linux/err.h>

#include <asm/mach-ath79/ath79.h>
#include <asm/mach-ath79/ar71xx_regs.h>

#define DRIVER_NAME	"ath79-wdt"

#define WDT_TIMEOUT	15	/* seconds */

#define WDOG_CTRL_LAST_RESET	BIT(31)
#define WDOG_CTRL_ACTION_MASK	3
#define WDOG_CTRL_ACTION_NONE	0	/* no action */
#define WDOG_CTRL_ACTION_GPI	1	/* general purpose interrupt */
#define WDOG_CTRL_ACTION_NMI	2	/* NMI */
#define WDOG_CTRL_ACTION_FCR	3	/* full chip reset */

static int nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
			   "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static int timeout = WDT_TIMEOUT;
module_param(timeout, int, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
			  "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");

static unsigned long wdt_flags;

#define WDT_FLAGS_BUSY		0
#define WDT_FLAGS_EXPECT_CLOSE	1

static struct clk *wdt_clk;
static unsigned long wdt_freq;
static int boot_status;
static int max_timeout;

static inline void ath79_wdt_keepalive(void)
{
	ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout);
	/* flush write */
	ath79_reset_rr(AR71XX_RESET_REG_WDOG);
}

static inline void ath79_wdt_enable(void)
{
	ath79_wdt_keepalive();
	ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
	/* flush write */
	ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
}

static inline void ath79_wdt_disable(void)
{
	ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
	/* flush write */
	ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
}

static int ath79_wdt_set_timeout(int val)
{
	if (val < 1 || val > max_timeout)
		return -EINVAL;

	timeout = val;
	ath79_wdt_keepalive();

	return 0;
}

static int ath79_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
		return -EBUSY;

	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	ath79_wdt_enable();

	return nonseekable_open(inode, file);
}

static int ath79_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
		ath79_wdt_disable();
	else {
		pr_crit(DRIVER_NAME ": device closed unexpectedly, "
			"watchdog timer will not stop!\n");
		ath79_wdt_keepalive();
	}

	clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);

	return 0;
}

static ssize_t ath79_wdt_write(struct file *file, const char *data,
				size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);

			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;

				if (c == 'V')
					set_bit(WDT_FLAGS_EXPECT_CLOSE,
						&wdt_flags);
			}
		}

		ath79_wdt_keepalive();
	}

	return len;
}

static const struct watchdog_info ath79_wdt_info = {
	.options		= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
				  WDIOF_MAGICCLOSE | WDIOF_CARDRESET,
	.firmware_version	= 0,
	.identity		= "ATH79 watchdog",
};

static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
			    unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int err;
	int t;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		err = copy_to_user(argp, &ath79_wdt_info,
				   sizeof(ath79_wdt_info)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
		err = put_user(0, p);
		break;

	case WDIOC_GETBOOTSTATUS:
		err = put_user(boot_status, p);
		break;

	case WDIOC_KEEPALIVE:
		ath79_wdt_keepalive();
		err = 0;
		break;

	case WDIOC_SETTIMEOUT:
		err = get_user(t, p);
		if (err)
			break;

		err = ath79_wdt_set_timeout(t);
		if (err)
			break;

		/* fallthrough */
	case WDIOC_GETTIMEOUT:
		err = put_user(timeout, p);
		break;

	default:
		err = -ENOTTY;
		break;
	}

	return err;
}

static const struct file_operations ath79_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= ath79_wdt_write,
	.unlocked_ioctl	= ath79_wdt_ioctl,
	.open		= ath79_wdt_open,
	.release	= ath79_wdt_release,
};

static struct miscdevice ath79_wdt_miscdev = {
	.minor = WATCHDOG_MINOR,
	.name = "watchdog",
	.fops = &ath79_wdt_fops,
};

static int __devinit ath79_wdt_probe(struct platform_device *pdev)
{
	u32 ctrl;
	int err;

	wdt_clk = clk_get(&pdev->dev, "wdt");
	if (IS_ERR(wdt_clk))
		return PTR_ERR(wdt_clk);

	err = clk_enable(wdt_clk);
	if (err)
		goto err_clk_put;

	wdt_freq = clk_get_rate(wdt_clk);
	if (!wdt_freq) {
		err = -EINVAL;
		goto err_clk_disable;
	}

	max_timeout = (0xfffffffful / wdt_freq);
	if (timeout < 1 || timeout > max_timeout) {
		timeout = max_timeout;
		dev_info(&pdev->dev,
			"timeout value must be 0 < timeout < %d, using %d\n",
			max_timeout, timeout);
	}

	ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
	boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;

	err = misc_register(&ath79_wdt_miscdev);
	if (err) {
		dev_err(&pdev->dev,
			"unable to register misc device, err=%d\n", err);
		goto err_clk_disable;
	}

	return 0;

err_clk_disable:
	clk_disable(wdt_clk);
err_clk_put:
	clk_put(wdt_clk);
	return err;
}

static int __devexit ath79_wdt_remove(struct platform_device *pdev)
{
	misc_deregister(&ath79_wdt_miscdev);
	clk_disable(wdt_clk);
	clk_put(wdt_clk);
	return 0;
}

static void ath97_wdt_shutdown(struct platform_device *pdev)
{
	ath79_wdt_disable();
}

static struct platform_driver ath79_wdt_driver = {
	.remove		= __devexit_p(ath79_wdt_remove),
	.shutdown	= ath97_wdt_shutdown,
	.driver		= {
		.name	= DRIVER_NAME,
		.owner	= THIS_MODULE,
	},
};

static int __init ath79_wdt_init(void)
{
	return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe);
}
module_init(ath79_wdt_init);

static void __exit ath79_wdt_exit(void)
{
	platform_driver_unregister(&ath79_wdt_driver);
}
module_exit(ath79_wdt_exit);

MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
f8394f61 GJ	1	/*
	2	* Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer.
	3	*
	4	* Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org>
	5	* Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
	6	*
	7	* This driver was based on: drivers/watchdog/ixp4xx_wdt.c
	8	* Author: Deepak Saxena <dsaxena@plexity.net>
	9	* Copyright 2004 (c) MontaVista, Software, Inc.
	10	*
	11	* which again was based on sa1100 driver,
	12	* Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
	13	*
	14	* This program is free software; you can redistribute it and/or modify it
	15	* under the terms of the GNU General Public License version 2 as published
	16	* by the Free Software Foundation.
	17	*
	18	*/
	19
	20	#include <linux/bitops.h>
	21	#include <linux/errno.h>
	22	#include <linux/fs.h>
	23	#include <linux/init.h>
	24	#include <linux/kernel.h>
	25	#include <linux/miscdevice.h>
	26	#include <linux/module.h>
	27	#include <linux/moduleparam.h>
	28	#include <linux/platform_device.h>
	29	#include <linux/types.h>
	30	#include <linux/watchdog.h>
	31	#include <linux/clk.h>
	32	#include <linux/err.h>
	33
	34	#include <asm/mach-ath79/ath79.h>
	35	#include <asm/mach-ath79/ar71xx_regs.h>
	36
	37	#define DRIVER_NAME "ath79-wdt"
	38
	39	#define WDT_TIMEOUT 15 /* seconds */
	40
	41	#define WDOG_CTRL_LAST_RESET BIT(31)
	42	#define WDOG_CTRL_ACTION_MASK 3
	43	#define WDOG_CTRL_ACTION_NONE 0 /* no action */
	44	#define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */
	45	#define WDOG_CTRL_ACTION_NMI 2 /* NMI */
	46	#define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */
	47
	48	static int nowayout = WATCHDOG_NOWAYOUT;
	49	module_param(nowayout, int, 0);
	50	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	51	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	52
	53	static int timeout = WDT_TIMEOUT;
	54	module_param(timeout, int, 0);
	55	MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
	56	"(default=" __MODULE_STRING(WDT_TIMEOUT) "s)");
	57
	58	static unsigned long wdt_flags;
	59
	60	#define WDT_FLAGS_BUSY 0
	61	#define WDT_FLAGS_EXPECT_CLOSE 1
	62
	63	static struct clk *wdt_clk;
	64	static unsigned long wdt_freq;
65	static int boot_status;
66	static int max_timeout;
67
68	static inline void ath79_wdt_keepalive(void)
69	{
70	ath79_reset_wr(AR71XX_RESET_REG_WDOG, wdt_freq * timeout);
86955e2b GJ	71	/* flush write */
86955e2b GJ	72	ath79_reset_rr(AR71XX_RESET_REG_WDOG);
f8394f61 GJ	73	}
	74
	75	static inline void ath79_wdt_enable(void)
	76	{
	77	ath79_wdt_keepalive();
	78	ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_FCR);
86955e2b GJ	79	/* flush write */
86955e2b GJ	80	ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
f8394f61 GJ	81	}
	82
	83	static inline void ath79_wdt_disable(void)
	84	{
	85	ath79_reset_wr(AR71XX_RESET_REG_WDOG_CTRL, WDOG_CTRL_ACTION_NONE);
86955e2b GJ	86	/* flush write */
86955e2b GJ	87	ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
f8394f61 GJ	88	}
	89
	90	static int ath79_wdt_set_timeout(int val)
	91	{
	92	if (val < 1 \|\| val > max_timeout)
	93	return -EINVAL;
	94
	95	timeout = val;
	96	ath79_wdt_keepalive();
	97
	98	return 0;
	99	}
	100
	101	static int ath79_wdt_open(struct inode inode, struct file file)
	102	{
	103	if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags))
	104	return -EBUSY;
	105
	106	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	107	ath79_wdt_enable();
	108
	109	return nonseekable_open(inode, file);
	110	}
	111
	112	static int ath79_wdt_release(struct inode inode, struct file file)
	113	{
	114	if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags))
	115	ath79_wdt_disable();
	116	else {
	117	pr_crit(DRIVER_NAME ": device closed unexpectedly, "
	118	"watchdog timer will not stop!\n");
	119	ath79_wdt_keepalive();
	120	}
	121
	122	clear_bit(WDT_FLAGS_BUSY, &wdt_flags);
	123	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	124
	125	return 0;
	126	}
	127
	128	static ssize_t ath79_wdt_write(struct file file, const char data,
	129	size_t len, loff_t *ppos)
	130	{
	131	if (len) {
	132	if (!nowayout) {
	133	size_t i;
	134
	135	clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags);
	136
	137	for (i = 0; i != len; i++) {
	138	char c;
	139
	140	if (get_user(c, data + i))
	141	return -EFAULT;
	142
	143	if (c == 'V')
	144	set_bit(WDT_FLAGS_EXPECT_CLOSE,
	145	&wdt_flags);
	146	}
	147	}
	148
	149	ath79_wdt_keepalive();
	150	}
	151
152	return len;
153	}
154
155	static const struct watchdog_info ath79_wdt_info = {
156	.options = WDIOF_SETTIMEOUT \| WDIOF_KEEPALIVEPING \|
157	WDIOF_MAGICCLOSE \| WDIOF_CARDRESET,
158	.firmware_version = 0,
159	.identity = "ATH79 watchdog",
160	};
161
162	static long ath79_wdt_ioctl(struct file *file, unsigned int cmd,
163	unsigned long arg)
164	{
165	void __user argp = (void __user )arg;
166	int __user *p = argp;
167	int err;
168	int t;
169
170	switch (cmd) {
171	case WDIOC_GETSUPPORT:
172	err = copy_to_user(argp, &ath79_wdt_info,
173	sizeof(ath79_wdt_info)) ? -EFAULT : 0;
174	break;
175
176	case WDIOC_GETSTATUS:
177	err = put_user(0, p);
178	break;
179
180	case WDIOC_GETBOOTSTATUS:
181	err = put_user(boot_status, p);
182	break;
183
184	case WDIOC_KEEPALIVE:
185	ath79_wdt_keepalive();
186	err = 0;
187	break;
188
189	case WDIOC_SETTIMEOUT:
190	err = get_user(t, p);
191	if (err)
192	break;
193
194	err = ath79_wdt_set_timeout(t);
195	if (err)
196	break;
197
198	/* fallthrough */
199	case WDIOC_GETTIMEOUT:
200	err = put_user(timeout, p);
201	break;
202
203	default:
204	err = -ENOTTY;
205	break;
206	}
207
208	return err;
209	}
210
211	static const struct file_operations ath79_wdt_fops = {
212	.owner = THIS_MODULE,
213	.llseek = no_llseek,
214	.write = ath79_wdt_write,
215	.unlocked_ioctl = ath79_wdt_ioctl,
216	.open = ath79_wdt_open,
217	.release = ath79_wdt_release,
218	};
219
220	static struct miscdevice ath79_wdt_miscdev = {
221	.minor = WATCHDOG_MINOR,
222	.name = "watchdog",
223	.fops = &ath79_wdt_fops,
224	};
225
226	static int __devinit ath79_wdt_probe(struct platform_device *pdev)
227	{
228	u32 ctrl;
229	int err;
230
231	wdt_clk = clk_get(&pdev->dev, "wdt");
232	if (IS_ERR(wdt_clk))
233	return PTR_ERR(wdt_clk);
234
235	err = clk_enable(wdt_clk);
236	if (err)
237	goto err_clk_put;
238
239	wdt_freq = clk_get_rate(wdt_clk);
240	if (!wdt_freq) {
241	err = -EINVAL;
242	goto err_clk_disable;
243	}
244
245	max_timeout = (0xfffffffful / wdt_freq);
246	if (timeout < 1 \|\| timeout > max_timeout) {
247	timeout = max_timeout;
248	dev_info(&pdev->dev,
249	"timeout value must be 0 < timeout < %d, using %d\n",
250	max_timeout, timeout);
251	}
252
253	ctrl = ath79_reset_rr(AR71XX_RESET_REG_WDOG_CTRL);
254	boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0;
255
256	err = misc_register(&ath79_wdt_miscdev);
257	if (err) {
258	dev_err(&pdev->dev,
259	"unable to register misc device, err=%d\n", err);
260	goto err_clk_disable;
261	}
262
263	return 0;
264
265	err_clk_disable:
266	clk_disable(wdt_clk);
267	err_clk_put:
268	clk_put(wdt_clk);
269	return err;
270	}
271
272	static int __devexit ath79_wdt_remove(struct platform_device *pdev)
273	{
274	misc_deregister(&ath79_wdt_miscdev);
275	clk_disable(wdt_clk);
276	clk_put(wdt_clk);
277	return 0;
278	}
279
280	static void ath97_wdt_shutdown(struct platform_device *pdev)
281	{
282	ath79_wdt_disable();
283	}
284
285	static struct platform_driver ath79_wdt_driver = {
286	.remove = __devexit_p(ath79_wdt_remove),
287	.shutdown = ath97_wdt_shutdown,
288	.driver = {
289	.name = DRIVER_NAME,
290	.owner = THIS_MODULE,
291	},
292	};
293
294	static int __init ath79_wdt_init(void)
295	{
296	return platform_driver_probe(&ath79_wdt_driver, ath79_wdt_probe);
297	}
298	module_init(ath79_wdt_init);
299
300	static void __exit ath79_wdt_exit(void)
301	{
302	platform_driver_unregister(&ath79_wdt_driver);
303	}
304	module_exit(ath79_wdt_exit);
305
306	MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver");
307	MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");
308	MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org");
309	MODULE_LICENSE("GPL v2");
310	MODULE_ALIAS("platform:" DRIVER_NAME);
311	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);