[deliverable/linux.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 ORION5X_TCLK		166666667
#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
c9a0c8a6	32	#define ORION5X_TCLK 166666667
22ac9232 SB	33	#define WDT_MAX_DURATION (0xffffffff / ORION5X_TCLK)
	34	#define WDT_IN_USE 0
	35	#define WDT_OK_TO_CLOSE 1
	36
	37	static int nowayout = WATCHDOG_NOWAYOUT;
	38	static int heartbeat = WDT_MAX_DURATION; /* (seconds) */
	39	static unsigned long wdt_status;
6d0f0dfd	40	static spinlock_t wdt_lock;
22ac9232 SB	41
	42	static void wdt_enable(void)
	43	{
	44	u32 reg;
	45
6d0f0dfd WVS	46	spin_lock(&wdt_lock);
6d0f0dfd WVS	47
22ac9232 SB	48	/* Set watchdog duration */
	49	writel(ORION5X_TCLK * heartbeat, WDT_VAL);
	50
	51	/* Clear watchdog timer interrupt */
	52	reg = readl(BRIDGE_CAUSE);
	53	reg &= ~WDT_INT_REQ;
	54	writel(reg, BRIDGE_CAUSE);
	55
	56	/* Enable watchdog timer */
	57	reg = readl(TIMER_CTRL);
	58	reg \|= WDT_EN;
	59	writel(reg, TIMER_CTRL);
	60
	61	/* Enable reset on watchdog */
	62	reg = readl(CPU_RESET_MASK);
	63	reg \|= WDT_RESET;
	64	writel(reg, CPU_RESET_MASK);
6d0f0dfd WVS	65
6d0f0dfd WVS	66	spin_unlock(&wdt_lock);
22ac9232 SB	67	}
	68
	69	static void wdt_disable(void)
	70	{
	71	u32 reg;
	72
6d0f0dfd WVS	73	spin_lock(&wdt_lock);
6d0f0dfd WVS	74
22ac9232 SB	75	/* Disable reset on watchdog */
	76	reg = readl(CPU_RESET_MASK);
	77	reg &= ~WDT_RESET;
	78	writel(reg, CPU_RESET_MASK);
	79
	80	/* Disable watchdog timer */
	81	reg = readl(TIMER_CTRL);
	82	reg &= ~WDT_EN;
	83	writel(reg, TIMER_CTRL);
6d0f0dfd WVS	84
	85	spin_unlock(&wdt_lock);
	86	}
	87
	88	static int orion5x_wdt_get_timeleft(int *time_left)
	89	{
	90	spin_lock(&wdt_lock);
	91	*time_left = readl(WDT_VAL) / ORION5X_TCLK;
	92	spin_unlock(&wdt_lock);
	93	return 0;
22ac9232 SB	94	}
	95
	96	static int orion5x_wdt_open(struct inode inode, struct file file)
	97	{
	98	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	99	return -EBUSY;
	100	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	101	wdt_enable();
	102	return nonseekable_open(inode, file);
	103	}
	104
22ac9232 SB	105	static ssize_t orion5x_wdt_write(struct file file, const char data,
	106	size_t len, loff_t *ppos)
	107	{
	108	if (len) {
	109	if (!nowayout) {
	110	size_t i;
	111
	112	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	113	for (i = 0; i != len; i++) {
	114	char c;
	115
	116	if (get_user(c, data + i))
	117	return -EFAULT;
	118	if (c == 'V')
	119	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	120	}
	121	}
	122	wdt_enable();
	123	}
	124	return len;
	125	}
	126
	127	static struct watchdog_info ident = {
	128	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	129	WDIOF_KEEPALIVEPING,
	130	.identity = "Orion5x Watchdog",
	131	};
	132
	133
	134	static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
	135	unsigned long arg)
	136	{
	137	int ret = -ENOTTY;
	138	int time;
	139
	140	switch (cmd) {
	141	case WDIOC_GETSUPPORT:
	142	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	143	sizeof(ident)) ? -EFAULT : 0;
	144	break;
	145
	146	case WDIOC_GETSTATUS:
	147	case WDIOC_GETBOOTSTATUS:
	148	ret = put_user(0, (int *)arg);
	149	break;
	150
	151	case WDIOC_KEEPALIVE:
	152	wdt_enable();
	153	ret = 0;
	154	break;
	155
	156	case WDIOC_SETTIMEOUT:
	157	ret = get_user(time, (int *)arg);
	158	if (ret)
	159	break;
	160
	161	if (time <= 0 \|\| time > WDT_MAX_DURATION) {
	162	ret = -EINVAL;
	163	break;
	164	}
	165	heartbeat = time;
	166	wdt_enable();
	167	/* Fall through */
	168
169	case WDIOC_GETTIMEOUT:
170	ret = put_user(heartbeat, (int *)arg);
171	break;
172
173	case WDIOC_GETTIMELEFT:
174	if (orion5x_wdt_get_timeleft(&time)) {
175	ret = -EINVAL;
176	break;
177	}
178	ret = put_user(time, (int *)arg);
179	break;
180	}
181	return ret;
182	}
183
184	static int orion5x_wdt_release(struct inode inode, struct file file)
185	{
186	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
187	wdt_disable();
188	else
189	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
190	"timer will not stop\n");
191	clear_bit(WDT_IN_USE, &wdt_status);
192	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
193
194	return 0;
195	}
196
197
198	static const struct file_operations orion5x_wdt_fops = {
199	.owner = THIS_MODULE,
200	.llseek = no_llseek,
201	.write = orion5x_wdt_write,
202	.unlocked_ioctl = orion5x_wdt_ioctl,
203	.open = orion5x_wdt_open,
204	.release = orion5x_wdt_release,
205	};
206
207	static struct miscdevice orion5x_wdt_miscdev = {
208	.minor = WATCHDOG_MINOR,
209	.name = "watchdog",
210	.fops = &orion5x_wdt_fops,
211	};
212
213	static int __init orion5x_wdt_init(void)
214	{
215	int ret;
216
6d0f0dfd WVS	217	spin_lock_init(&wdt_lock);
6d0f0dfd WVS	218
22ac9232 SB	219	ret = misc_register(&orion5x_wdt_miscdev);
	220	if (ret == 0)
	221	printk("Orion5x Watchdog Timer: heartbeat %d sec\n",
	222	heartbeat);
	223
	224	return ret;
	225	}
	226
	227	static void __exit orion5x_wdt_exit(void)
	228	{
	229	misc_deregister(&orion5x_wdt_miscdev);
	230	}
	231
	232	module_init(orion5x_wdt_init);
	233	module_exit(orion5x_wdt_exit);
	234
	235	MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
	236	MODULE_DESCRIPTION("Orion5x Processor Watchdog");
	237
	238	module_param(heartbeat, int, 0);
	239	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default is "
	240	__MODULE_STRING(WDT_MAX_DURATION) ")");
	241
	242	module_param(nowayout, int, 0);
	243	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	244
	245	MODULE_LICENSE("GPL");
	246	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);