[linux-2.6-block.git] / drivers / watchdog / mtx-1_wdt.c

// SPDX-License-Identifier: GPL-2.0+
/*
 *      Driver for the MTX-1 Watchdog.
 *
 *      (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
 *							All Rights Reserved.
 *                              http://www.4g-systems.biz
 *
 *	(C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
 *      (c) Copyright 2005    4G Systems <info@4g-systems.biz>
 *
 *      Release 0.01.
 *      Author: Michael Stickel  michael.stickel@4g-systems.biz
 *
 *      Release 0.02.
 *	Author: Florian Fainelli florian@openwrt.org
 *		use the Linux watchdog/timer APIs
 *
 *      The Watchdog is configured to reset the MTX-1
 *      if it is not triggered for 100 seconds.
 *      It should not be triggered more often than 1.6 seconds.
 *
 *      A timer triggers the watchdog every 5 seconds, until
 *      it is opened for the first time. After the first open
 *      it MUST be triggered every 2..95 seconds.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/ioport.h>
#include <linux/timer.h>
#include <linux/completion.h>
#include <linux/jiffies.h>
#include <linux/watchdog.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/uaccess.h>
#include <linux/gpio.h>

#include <asm/mach-au1x00/au1000.h>

#define MTX1_WDT_INTERVAL	(5 * HZ)

static int ticks = 100 * HZ;

static struct {
	struct completion stop;
	spinlock_t lock;
	int running;
	struct timer_list timer;
	int queue;
	int default_ticks;
	unsigned long inuse;
	unsigned gpio;
	unsigned int gstate;
} mtx1_wdt_device;

static void mtx1_wdt_trigger(struct timer_list *unused)
{
	spin_lock(&mtx1_wdt_device.lock);
	if (mtx1_wdt_device.running)
		ticks--;

	/* toggle wdt gpio */
	mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
	gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);

	if (mtx1_wdt_device.queue && ticks)
		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
	else
		complete(&mtx1_wdt_device.stop);
	spin_unlock(&mtx1_wdt_device.lock);
}

static void mtx1_wdt_reset(void)
{
	ticks = mtx1_wdt_device.default_ticks;
}


static void mtx1_wdt_start(void)
{
	unsigned long flags;

	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
	if (!mtx1_wdt_device.queue) {
		mtx1_wdt_device.queue = 1;
		mtx1_wdt_device.gstate = 1;
		gpio_set_value(mtx1_wdt_device.gpio, 1);
		mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
	}
	mtx1_wdt_device.running++;
	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
}

static int mtx1_wdt_stop(void)
{
	unsigned long flags;

	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
	if (mtx1_wdt_device.queue) {
		mtx1_wdt_device.queue = 0;
		mtx1_wdt_device.gstate = 0;
		gpio_set_value(mtx1_wdt_device.gpio, 0);
	}
	ticks = mtx1_wdt_device.default_ticks;
	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
	return 0;
}

/* Filesystem functions */

static int mtx1_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
		return -EBUSY;
	return nonseekable_open(inode, file);
}


static int mtx1_wdt_release(struct inode *inode, struct file *file)
{
	clear_bit(0, &mtx1_wdt_device.inuse);
	return 0;
}

static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
							unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = (int __user *)argp;
	unsigned int value;
	static const struct watchdog_info ident = {
		.options = WDIOF_CARDRESET,
		.identity = "MTX-1 WDT",
	};

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		if (copy_to_user(argp, &ident, sizeof(ident)))
			return -EFAULT;
		break;
	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		put_user(0, p);
		break;
	case WDIOC_SETOPTIONS:
		if (get_user(value, p))
			return -EFAULT;
		if (value & WDIOS_ENABLECARD)
			mtx1_wdt_start();
		else if (value & WDIOS_DISABLECARD)
			mtx1_wdt_stop();
		else
			return -EINVAL;
		return 0;
	case WDIOC_KEEPALIVE:
		mtx1_wdt_reset();
		break;
	default:
		return -ENOTTY;
	}
	return 0;
}


static ssize_t mtx1_wdt_write(struct file *file, const char *buf,
						size_t count, loff_t *ppos)
{
	if (!count)
		return -EIO;
	mtx1_wdt_reset();
	return count;
}

static const struct file_operations mtx1_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.unlocked_ioctl	= mtx1_wdt_ioctl,
	.open		= mtx1_wdt_open,
	.write		= mtx1_wdt_write,
	.release	= mtx1_wdt_release,
};


static struct miscdevice mtx1_wdt_misc = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &mtx1_wdt_fops,
};


static int mtx1_wdt_probe(struct platform_device *pdev)
{
	int ret;

	mtx1_wdt_device.gpio = pdev->resource[0].start;
	ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
				GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to request gpio");
		return ret;
	}

	spin_lock_init(&mtx1_wdt_device.lock);
	init_completion(&mtx1_wdt_device.stop);
	mtx1_wdt_device.queue = 0;
	clear_bit(0, &mtx1_wdt_device.inuse);
	timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0);
	mtx1_wdt_device.default_ticks = ticks;

	ret = misc_register(&mtx1_wdt_misc);
	if (ret < 0) {
		dev_err(&pdev->dev, "failed to register\n");
		return ret;
	}
	mtx1_wdt_start();
	dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
	return 0;
}

static int mtx1_wdt_remove(struct platform_device *pdev)
{
	/* FIXME: do we need to lock this test ? */
	if (mtx1_wdt_device.queue) {
		mtx1_wdt_device.queue = 0;
		wait_for_completion(&mtx1_wdt_device.stop);
	}

	misc_deregister(&mtx1_wdt_misc);
	return 0;
}

static struct platform_driver mtx1_wdt_driver = {
	.probe = mtx1_wdt_probe,
	.remove = mtx1_wdt_remove,
	.driver.name = "mtx1-wdt",
	.driver.owner = THIS_MODULE,
};

module_platform_driver(mtx1_wdt_driver);

MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:mtx1-wdt");
Commit	Line	Data
2e62c498	1	// SPDX-License-Identifier: GPL-2.0+
04bf3b4f FF	2	/*
	3	* Driver for the MTX-1 Watchdog.
	4	*
ed78c2da AC	5	* (C) Copyright 2005 4G Systems <info@4g-systems.biz>,
ed78c2da AC	6	* All Rights Reserved.
04bf3b4f FF	7	* http://www.4g-systems.biz
04bf3b4f FF	8	*
143a2e54	9	* (C) Copyright 2007 OpenWrt.org, Florian Fainelli <florian@openwrt.org>
04bf3b4f FF	10	* (c) Copyright 2005 4G Systems <info@4g-systems.biz>
	11	*
	12	* Release 0.01.
	13	* Author: Michael Stickel michael.stickel@4g-systems.biz
	14	*
	15	* Release 0.02.
	16	* Author: Florian Fainelli florian@openwrt.org
	17	* use the Linux watchdog/timer APIs
	18	*
	19	* The Watchdog is configured to reset the MTX-1
	20	* if it is not triggered for 100 seconds.
	21	* It should not be triggered more often than 1.6 seconds.
	22	*
	23	* A timer triggers the watchdog every 5 seconds, until
	24	* it is opened for the first time. After the first open
	25	* it MUST be triggered every 2..95 seconds.
	26	*/
	27
	28	#include <linux/module.h>
	29	#include <linux/moduleparam.h>
	30	#include <linux/types.h>
	31	#include <linux/errno.h>
	32	#include <linux/miscdevice.h>
	33	#include <linux/fs.h>
04bf3b4f FF	34	#include <linux/ioport.h>
	35	#include <linux/timer.h>
	36	#include <linux/completion.h>
	37	#include <linux/jiffies.h>
	38	#include <linux/watchdog.h>
6ea8115b	39	#include <linux/platform_device.h>
ed78c2da AC	40	#include <linux/io.h>
	41	#include <linux/uaccess.h>
	42	#include <linux/gpio.h>
04bf3b4f FF	43
	44	#include <asm/mach-au1x00/au1000.h>
	45
	46	#define MTX1_WDT_INTERVAL (5 * HZ)
	47
	48	static int ticks = 100 * HZ;
	49
	50	static struct {
	51	struct completion stop;
ed78c2da	52	spinlock_t lock;
996d62d4	53	int running;
04bf3b4f	54	struct timer_list timer;
996d62d4	55	int queue;
04bf3b4f FF	56	int default_ticks;
04bf3b4f FF	57	unsigned long inuse;
6ea8115b	58	unsigned gpio;
2ea4e76e	59	unsigned int gstate;
04bf3b4f FF	60	} mtx1_wdt_device;
04bf3b4f FF	61
e99e88a9	62	static void mtx1_wdt_trigger(struct timer_list *unused)
04bf3b4f	63	{
ed78c2da	64	spin_lock(&mtx1_wdt_device.lock);
04bf3b4f FF	65	if (mtx1_wdt_device.running)
04bf3b4f FF	66	ticks--;
b7f720d6 ML	67
b7f720d6 ML	68	/* toggle wdt gpio */
2ea4e76e FF	69	mtx1_wdt_device.gstate = !mtx1_wdt_device.gstate;
2ea4e76e FF	70	gpio_set_value(mtx1_wdt_device.gpio, mtx1_wdt_device.gstate);
04bf3b4f FF	71
	72	if (mtx1_wdt_device.queue && ticks)
	73	mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
ed78c2da	74	else
04bf3b4f	75	complete(&mtx1_wdt_device.stop);
ed78c2da	76	spin_unlock(&mtx1_wdt_device.lock);
04bf3b4f FF	77	}
	78
	79	static void mtx1_wdt_reset(void)
	80	{
	81	ticks = mtx1_wdt_device.default_ticks;
	82	}
	83
	84
	85	static void mtx1_wdt_start(void)
	86	{
f80e919b FF	87	unsigned long flags;
f80e919b FF	88
ed78c2da	89	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
04bf3b4f FF	90	if (!mtx1_wdt_device.queue) {
04bf3b4f FF	91	mtx1_wdt_device.queue = 1;
b7f720d6	92	mtx1_wdt_device.gstate = 1;
2ea4e76e	93	gpio_set_value(mtx1_wdt_device.gpio, 1);
04bf3b4f FF	94	mod_timer(&mtx1_wdt_device.timer, jiffies + MTX1_WDT_INTERVAL);
	95	}
	96	mtx1_wdt_device.running++;
ed78c2da	97	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
04bf3b4f FF	98	}
	99
	100	static int mtx1_wdt_stop(void)
	101	{
f80e919b FF	102	unsigned long flags;
f80e919b FF	103
ed78c2da	104	spin_lock_irqsave(&mtx1_wdt_device.lock, flags);
04bf3b4f FF	105	if (mtx1_wdt_device.queue) {
04bf3b4f FF	106	mtx1_wdt_device.queue = 0;
b7f720d6	107	mtx1_wdt_device.gstate = 0;
2ea4e76e	108	gpio_set_value(mtx1_wdt_device.gpio, 0);
04bf3b4f	109	}
04bf3b4f	110	ticks = mtx1_wdt_device.default_ticks;
ed78c2da	111	spin_unlock_irqrestore(&mtx1_wdt_device.lock, flags);
04bf3b4f FF	112	return 0;
	113	}
	114
	115	/* Filesystem functions */
	116
	117	static int mtx1_wdt_open(struct inode inode, struct file file)
	118	{
	119	if (test_and_set_bit(0, &mtx1_wdt_device.inuse))
	120	return -EBUSY;
04bf3b4f FF	121	return nonseekable_open(inode, file);
	122	}
	123
	124
	125	static int mtx1_wdt_release(struct inode inode, struct file file)
	126	{
	127	clear_bit(0, &mtx1_wdt_device.inuse);
	128	return 0;
	129	}
	130
ed78c2da AC	131	static long mtx1_wdt_ioctl(struct file *file, unsigned int cmd,
ed78c2da AC	132	unsigned long arg)
04bf3b4f FF	133	{
04bf3b4f FF	134	void __user argp = (void __user )arg;
ed78c2da	135	int __user p = (int __user )argp;
04bf3b4f	136	unsigned int value;
ed78c2da	137	static const struct watchdog_info ident = {
04bf3b4f FF	138	.options = WDIOF_CARDRESET,
	139	.identity = "MTX-1 WDT",
	140	};
	141
ed78c2da	142	switch (cmd) {
0c06090c WVS	143	case WDIOC_GETSUPPORT:
	144	if (copy_to_user(argp, &ident, sizeof(ident)))
	145	return -EFAULT;
ed78c2da AC	146	break;
	147	case WDIOC_GETSTATUS:
	148	case WDIOC_GETBOOTSTATUS:
	149	put_user(0, p);
	150	break;
ed78c2da AC	151	case WDIOC_SETOPTIONS:
	152	if (get_user(value, p))
	153	return -EFAULT;
	154	if (value & WDIOS_ENABLECARD)
	155	mtx1_wdt_start();
	156	else if (value & WDIOS_DISABLECARD)
	157	mtx1_wdt_stop();
	158	else
	159	return -EINVAL;
	160	return 0;
0c06090c WVS	161	case WDIOC_KEEPALIVE:
	162	mtx1_wdt_reset();
	163	break;
ed78c2da AC	164	default:
ed78c2da AC	165	return -ENOTTY;
04bf3b4f FF	166	}
	167	return 0;
	168	}
	169
	170
ed78c2da AC	171	static ssize_t mtx1_wdt_write(struct file file, const char buf,
ed78c2da AC	172	size_t count, loff_t *ppos)
04bf3b4f FF	173	{
	174	if (!count)
	175	return -EIO;
04bf3b4f FF	176	mtx1_wdt_reset();
	177	return count;
	178	}
	179
b47a166e	180	static const struct file_operations mtx1_wdt_fops = {
5f3b2756	181	.owner = THIS_MODULE,
04bf3b4f	182	.llseek = no_llseek,
ed78c2da	183	.unlocked_ioctl = mtx1_wdt_ioctl,
5f3b2756 WVS	184	.open = mtx1_wdt_open,
	185	.write = mtx1_wdt_write,
	186	.release = mtx1_wdt_release,
04bf3b4f FF	187	};
	188
	189
	190	static struct miscdevice mtx1_wdt_misc = {
5f3b2756 WVS	191	.minor = WATCHDOG_MINOR,
	192	.name = "watchdog",
	193	.fops = &mtx1_wdt_fops,
04bf3b4f FF	194	};
	195
	196
2d991a16	197	static int mtx1_wdt_probe(struct platform_device *pdev)
04bf3b4f FF	198	{
	199	int ret;
	200
6ea8115b	201	mtx1_wdt_device.gpio = pdev->resource[0].start;
d3a33a95	202	ret = devm_gpio_request_one(&pdev->dev, mtx1_wdt_device.gpio,
9b19d40a FF	203	GPIOF_OUT_INIT_HIGH, "mtx1-wdt");
	204	if (ret < 0) {
	205	dev_err(&pdev->dev, "failed to request gpio");
	206	return ret;
	207	}
6ea8115b	208
ed78c2da	209	spin_lock_init(&mtx1_wdt_device.lock);
04bf3b4f FF	210	init_completion(&mtx1_wdt_device.stop);
04bf3b4f FF	211	mtx1_wdt_device.queue = 0;
04bf3b4f	212	clear_bit(0, &mtx1_wdt_device.inuse);
e99e88a9	213	timer_setup(&mtx1_wdt_device.timer, mtx1_wdt_trigger, 0);
04bf3b4f FF	214	mtx1_wdt_device.default_ticks = ticks;
04bf3b4f FF	215
ed78c2da AC	216	ret = misc_register(&mtx1_wdt_misc);
ed78c2da AC	217	if (ret < 0) {
fad0a9dd	218	dev_err(&pdev->dev, "failed to register\n");
ed78c2da AC	219	return ret;
ed78c2da AC	220	}
04bf3b4f	221	mtx1_wdt_start();
fad0a9dd	222	dev_info(&pdev->dev, "MTX-1 Watchdog driver\n");
04bf3b4f FF	223	return 0;
	224	}
	225
4b12b896	226	static int mtx1_wdt_remove(struct platform_device *pdev)
04bf3b4f	227	{
ed78c2da	228	/* FIXME: do we need to lock this test ? */
04bf3b4f FF	229	if (mtx1_wdt_device.queue) {
	230	mtx1_wdt_device.queue = 0;
	231	wait_for_completion(&mtx1_wdt_device.stop);
	232	}
9b19d40a	233
04bf3b4f	234	misc_deregister(&mtx1_wdt_misc);
6ea8115b FF	235	return 0;
	236	}
	237
db98f89a	238	static struct platform_driver mtx1_wdt_driver = {
6ea8115b	239	.probe = mtx1_wdt_probe,
82268714	240	.remove = mtx1_wdt_remove,
6ea8115b	241	.driver.name = "mtx1-wdt",
f37d193c	242	.driver.owner = THIS_MODULE,
6ea8115b FF	243	};
6ea8115b FF	244
b8ec6118	245	module_platform_driver(mtx1_wdt_driver);
04bf3b4f FF	246
	247	MODULE_AUTHOR("Michael Stickel, Florian Fainelli");
	248	MODULE_DESCRIPTION("Driver for the MTX-1 watchdog");
	249	MODULE_LICENSE("GPL");
f37d193c	250	MODULE_ALIAS("platform:mtx1-wdt");