[linux-2.6-block.git] / drivers / watchdog / orion5x_wdt.c

/*
 * drivers/watchdog/orion5x_wdt.c
 *
 * Watchdog driver for Orion5x processors
 *
 * Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
 *
 * This file is licensed under  the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/spinlock.h>

/*
 * Watchdog timer block registers.
 */
#define TIMER_CTRL		(TIMER_VIRT_BASE + 0x0000)
#define  WDT_EN			0x0010
#define WDT_VAL			(TIMER_VIRT_BASE + 0x0024)

#define WDT_MAX_DURATION	(0xffffffff / ORION5X_TCLK)
#define WDT_IN_USE		0
#define WDT_OK_TO_CLOSE		1

static int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat =  WDT_MAX_DURATION;	/* (seconds) */
static unsigned long wdt_status;
static spinlock_t wdt_lock;

static void wdt_enable(void)
{
	u32 reg;

	spin_lock(&wdt_lock);

	/* Set watchdog duration */
	writel(ORION5X_TCLK * heartbeat, WDT_VAL);

	/* Clear watchdog timer interrupt */
	reg = readl(BRIDGE_CAUSE);
	reg &= ~WDT_INT_REQ;
	writel(reg, BRIDGE_CAUSE);

	/* Enable watchdog timer */
	reg = readl(TIMER_CTRL);
	reg |= WDT_EN;
	writel(reg, TIMER_CTRL);

	/* Enable reset on watchdog */
	reg = readl(CPU_RESET_MASK);
	reg |= WDT_RESET;
	writel(reg, CPU_RESET_MASK);

	spin_unlock(&wdt_lock);
}

static void wdt_disable(void)
{
	u32 reg;

	spin_lock(&wdt_lock);

	/* Disable reset on watchdog */
	reg = readl(CPU_RESET_MASK);
	reg &= ~WDT_RESET;
	writel(reg, CPU_RESET_MASK);

	/* Disable watchdog timer */
	reg = readl(TIMER_CTRL);
	reg &= ~WDT_EN;
	writel(reg, TIMER_CTRL);

	spin_unlock(&wdt_lock);
}

static int orion5x_wdt_get_timeleft(int *time_left)
{
	spin_lock(&wdt_lock);
	*time_left = readl(WDT_VAL) / ORION5X_TCLK;
	spin_unlock(&wdt_lock);
	return 0;
}

static int orion5x_wdt_open(struct inode *inode, struct file *file)
{
	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
		return -EBUSY;
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	wdt_enable();
	return nonseekable_open(inode, file);
}

static ssize_t orion5x_wdt_write(struct file *file, const char *data,
					size_t len, loff_t *ppos)
{
	if (len) {
		if (!nowayout) {
			size_t i;

			clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
			for (i = 0; i != len; i++) {
				char c;

				if (get_user(c, data + i))
					return -EFAULT;
				if (c == 'V')
					set_bit(WDT_OK_TO_CLOSE, &wdt_status);
			}
		}
		wdt_enable();
	}
	return len;
}

static struct watchdog_info ident = {
	.options	= WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING,
	.identity	= "Orion5x Watchdog",
};


static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
				unsigned long arg)
{
	int ret = -ENOTTY;
	int time;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		ret = copy_to_user((struct watchdog_info *)arg, &ident,
				   sizeof(ident)) ? -EFAULT : 0;
		break;

	case WDIOC_GETSTATUS:
	case WDIOC_GETBOOTSTATUS:
		ret = put_user(0, (int *)arg);
		break;

	case WDIOC_KEEPALIVE:
		wdt_enable();
		ret = 0;
		break;

	case WDIOC_SETTIMEOUT:
		ret = get_user(time, (int *)arg);
		if (ret)
			break;

		if (time <= 0 || time > WDT_MAX_DURATION) {
			ret = -EINVAL;
			break;
		}
		heartbeat = time;
		wdt_enable();
		/* Fall through */

	case WDIOC_GETTIMEOUT:
		ret = put_user(heartbeat, (int *)arg);
		break;

	case WDIOC_GETTIMELEFT:
		if (orion5x_wdt_get_timeleft(&time)) {
			ret = -EINVAL;
			break;
		}
		ret = put_user(time, (int *)arg);
		break;
	}
	return ret;
}

static int orion5x_wdt_release(struct inode *inode, struct file *file)
{
	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
		wdt_disable();
	else
		printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
					"timer will not stop\n");
	clear_bit(WDT_IN_USE, &wdt_status);
	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);

	return 0;
}


static const struct file_operations orion5x_wdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.write		= orion5x_wdt_write,
	.unlocked_ioctl	= orion5x_wdt_ioctl,
	.open		= orion5x_wdt_open,
	.release	= orion5x_wdt_release,
};

static struct miscdevice orion5x_wdt_miscdev = {
	.minor		= WATCHDOG_MINOR,
	.name		= "watchdog",
	.fops		= &orion5x_wdt_fops,
};

static int __init orion5x_wdt_init(void)
{
	int ret;

	spin_lock_init(&wdt_lock);

	ret = misc_register(&orion5x_wdt_miscdev);
	if (ret == 0)
		printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
								heartbeat);

	return ret;
}

static void __exit orion5x_wdt_exit(void)
{
	misc_deregister(&orion5x_wdt_miscdev);
}

module_init(orion5x_wdt_init);
module_exit(orion5x_wdt_exit);

MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
MODULE_DESCRIPTION("Orion5x Processor Watchdog");

module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
					__MODULE_STRING(WDT_MAX_DURATION) ")");

module_param(nowayout, int, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");

MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
22ac9232 SB	1	/*
	2	* drivers/watchdog/orion5x_wdt.c
	3	*
	4	* Watchdog driver for Orion5x processors
	5	*
	6	* Author: Sylver Bruneau <sylver.bruneau@googlemail.com>
	7	*
	8	* This file is licensed under the terms of the GNU General Public
	9	* License version 2. This program is licensed "as is" without any
	10	* warranty of any kind, whether express or implied.
	11	*/
	12
	13	#include <linux/module.h>
	14	#include <linux/moduleparam.h>
	15	#include <linux/types.h>
	16	#include <linux/kernel.h>
	17	#include <linux/fs.h>
	18	#include <linux/miscdevice.h>
	19	#include <linux/watchdog.h>
	20	#include <linux/init.h>
	21	#include <linux/uaccess.h>
	22	#include <linux/io.h>
6d0f0dfd	23	#include <linux/spinlock.h>
22ac9232 SB	24
	25	/*
	26	* Watchdog timer block registers.
	27	*/
	28	#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
	29	#define WDT_EN 0x0010
	30	#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)
	31
	32	#define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK)
	33	#define WDT_IN_USE 0
	34	#define WDT_OK_TO_CLOSE 1
	35
	36	static int nowayout = WATCHDOG_NOWAYOUT;
	37	static int heartbeat = WDT_MAX_DURATION; /* (seconds) */
	38	static unsigned long wdt_status;
6d0f0dfd	39	static spinlock_t wdt_lock;
22ac9232 SB	40
	41	static void wdt_enable(void)
	42	{
	43	u32 reg;
	44
6d0f0dfd WVS	45	spin_lock(&wdt_lock);
6d0f0dfd WVS	46
22ac9232 SB	47	/* Set watchdog duration */
	48	writel(ORION5X_TCLK * heartbeat, WDT_VAL);
	49
	50	/* Clear watchdog timer interrupt */
	51	reg = readl(BRIDGE_CAUSE);
	52	reg &= ~WDT_INT_REQ;
	53	writel(reg, BRIDGE_CAUSE);
	54
	55	/* Enable watchdog timer */
	56	reg = readl(TIMER_CTRL);
	57	reg \|= WDT_EN;
	58	writel(reg, TIMER_CTRL);
	59
	60	/* Enable reset on watchdog */
	61	reg = readl(CPU_RESET_MASK);
	62	reg \|= WDT_RESET;
	63	writel(reg, CPU_RESET_MASK);
6d0f0dfd WVS	64
6d0f0dfd WVS	65	spin_unlock(&wdt_lock);
22ac9232 SB	66	}
	67
	68	static void wdt_disable(void)
	69	{
	70	u32 reg;
	71
6d0f0dfd WVS	72	spin_lock(&wdt_lock);
6d0f0dfd WVS	73
22ac9232 SB	74	/* Disable reset on watchdog */
	75	reg = readl(CPU_RESET_MASK);
	76	reg &= ~WDT_RESET;
	77	writel(reg, CPU_RESET_MASK);
	78
	79	/* Disable watchdog timer */
	80	reg = readl(TIMER_CTRL);
	81	reg &= ~WDT_EN;
	82	writel(reg, TIMER_CTRL);
6d0f0dfd WVS	83
	84	spin_unlock(&wdt_lock);
	85	}
	86
	87	static int orion5x_wdt_get_timeleft(int *time_left)
	88	{
	89	spin_lock(&wdt_lock);
	90	*time_left = readl(WDT_VAL) / ORION5X_TCLK;
	91	spin_unlock(&wdt_lock);
	92	return 0;
22ac9232 SB	93	}
	94
	95	static int orion5x_wdt_open(struct inode inode, struct file file)
	96	{
	97	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	98	return -EBUSY;
	99	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	100	wdt_enable();
	101	return nonseekable_open(inode, file);
	102	}
	103
22ac9232 SB	104	static ssize_t orion5x_wdt_write(struct file file, const char data,
	105	size_t len, loff_t *ppos)
	106	{
	107	if (len) {
	108	if (!nowayout) {
	109	size_t i;
	110
	111	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	112	for (i = 0; i != len; i++) {
	113	char c;
	114
	115	if (get_user(c, data + i))
	116	return -EFAULT;
	117	if (c == 'V')
	118	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	119	}
	120	}
	121	wdt_enable();
	122	}
	123	return len;
	124	}
	125
	126	static struct watchdog_info ident = {
	127	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	128	WDIOF_KEEPALIVEPING,
	129	.identity = "Orion5x Watchdog",
	130	};
	131
	132
	133	static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
	134	unsigned long arg)
	135	{
	136	int ret = -ENOTTY;
	137	int time;
	138
	139	switch (cmd) {
	140	case WDIOC_GETSUPPORT:
	141	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	142	sizeof(ident)) ? -EFAULT : 0;
	143	break;
	144
	145	case WDIOC_GETSTATUS:
	146	case WDIOC_GETBOOTSTATUS:
	147	ret = put_user(0, (int *)arg);
	148	break;
	149
	150	case WDIOC_KEEPALIVE:
	151	wdt_enable();
	152	ret = 0;
	153	break;
	154
	155	case WDIOC_SETTIMEOUT:
	156	ret = get_user(time, (int *)arg);
	157	if (ret)
	158	break;
	159
	160	if (time <= 0 \|\| time > WDT_MAX_DURATION) {
	161	ret = -EINVAL;
	162	break;
	163	}
	164	heartbeat = time;
	165	wdt_enable();
	166	/* Fall through */
	167
168	case WDIOC_GETTIMEOUT:
169	ret = put_user(heartbeat, (int *)arg);
170	break;
171
172	case WDIOC_GETTIMELEFT:
173	if (orion5x_wdt_get_timeleft(&time)) {
174	ret = -EINVAL;
175	break;
176	}
177	ret = put_user(time, (int *)arg);
178	break;
179	}
180	return ret;
181	}
182
183	static int orion5x_wdt_release(struct inode inode, struct file file)
184	{
185	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
186	wdt_disable();
187	else
188	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
189	"timer will not stop\n");
190	clear_bit(WDT_IN_USE, &wdt_status);
191	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
192
193	return 0;
194	}
195
196
197	static const struct file_operations orion5x_wdt_fops = {
198	.owner = THIS_MODULE,
199	.llseek = no_llseek,
200	.write = orion5x_wdt_write,
201	.unlocked_ioctl = orion5x_wdt_ioctl,
202	.open = orion5x_wdt_open,
203	.release = orion5x_wdt_release,
204	};
205
206	static struct miscdevice orion5x_wdt_miscdev = {
207	.minor = WATCHDOG_MINOR,
208	.name = "watchdog",
209	.fops = &orion5x_wdt_fops,
210	};
211
212	static int __init orion5x_wdt_init(void)
213	{
214	int ret;
215
6d0f0dfd WVS	216	spin_lock_init(&wdt_lock);
6d0f0dfd WVS	217
22ac9232 SB	218	ret = misc_register(&orion5x_wdt_miscdev);
	219	if (ret == 0)
	220	printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
	221	heartbeat);
	222
	223	return ret;
	224	}
	225
	226	static void __exit orion5x_wdt_exit(void)
	227	{
	228	misc_deregister(&orion5x_wdt_miscdev);
	229	}
	230
	231	module_init(orion5x_wdt_init);
	232	module_exit(orion5x_wdt_exit);
	233
	234	MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
	235	MODULE_DESCRIPTION("Orion5x Processor Watchdog");
	236
	237	module_param(heartbeat, int, 0);
	238	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
	239	__MODULE_STRING(WDT_MAX_DURATION) ")");
	240
	241	module_param(nowayout, int, 0);
	242	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	243
	244	MODULE_LICENSE("GPL");
	245	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);