[linux-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/platform_device.h>
#include <linux/watchdog.h>
#include <linux/init.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <plat/orion5x_wdt.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_CYCLE_COUNT	0xffffffff
#define WDT_IN_USE		0
#define WDT_OK_TO_CLOSE		1

static int nowayout = WATCHDOG_NOWAYOUT;
static int heartbeat = -1;		/* module parameter (seconds) */
static unsigned int wdt_max_duration;	/* (seconds) */
static unsigned int wdt_tclk;
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(wdt_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) / wdt_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 __devinit orion5x_wdt_probe(struct platform_device *pdev)
{
	struct orion5x_wdt_platform_data *pdata = pdev->dev.platform_data;
	int ret;

	if (pdata) {
		wdt_tclk = pdata->tclk;
	} else {
		printk(KERN_ERR "Orion5x Watchdog misses platform data\n");
		return -ENODEV;
	}

	if (orion5x_wdt_miscdev.parent)
		return -EBUSY;
	orion5x_wdt_miscdev.parent = &pdev->dev;

	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
	if (heartbeat <= 0 || heartbeat > wdt_max_duration)
		heartbeat = wdt_max_duration;

	ret = misc_register(&orion5x_wdt_miscdev);
	if (ret)
		return ret;

	printk(KERN_INFO "Orion5x Watchdog Timer: Initial timeout %d sec%s\n",
				heartbeat, nowayout ? ", nowayout" : "");
	return 0;
}

static int __devexit orion5x_wdt_remove(struct platform_device *pdev)
{
	int ret;

	if (test_bit(WDT_IN_USE, &wdt_status)) {
		wdt_disable();
		clear_bit(WDT_IN_USE, &wdt_status);
	}

	ret = misc_deregister(&orion5x_wdt_miscdev);
	if (!ret)
		orion5x_wdt_miscdev.parent = NULL;

	return ret;
}

static struct platform_driver orion5x_wdt_driver = {
	.probe		= orion5x_wdt_probe,
	.remove		= __devexit_p(orion5x_wdt_remove),
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= "orion5x_wdt",
	},
};

static int __init orion5x_wdt_init(void)
{
	spin_lock_init(&wdt_lock);
	return platform_driver_register(&orion5x_wdt_driver);
}

static void __exit orion5x_wdt_exit(void)
{
	platform_driver_unregister(&orion5x_wdt_driver);
}

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");

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>
9e058d4f	19	#include <linux/platform_device.h>
22ac9232 SB	20	#include <linux/watchdog.h>
	21	#include <linux/init.h>
	22	#include <linux/uaccess.h>
	23	#include <linux/io.h>
6d0f0dfd	24	#include <linux/spinlock.h>
9e058d4f	25	#include <plat/orion5x_wdt.h>
22ac9232 SB	26
	27	/*
	28	* Watchdog timer block registers.
	29	*/
	30	#define TIMER_CTRL (TIMER_VIRT_BASE + 0x0000)
	31	#define WDT_EN 0x0010
	32	#define WDT_VAL (TIMER_VIRT_BASE + 0x0024)
	33
9e058d4f	34	#define WDT_MAX_CYCLE_COUNT 0xffffffff
22ac9232 SB	35	#define WDT_IN_USE 0
	36	#define WDT_OK_TO_CLOSE 1
	37
	38	static int nowayout = WATCHDOG_NOWAYOUT;
9e058d4f TR	39	static int heartbeat = -1; /* module parameter (seconds) */
	40	static unsigned int wdt_max_duration; /* (seconds) */
	41	static unsigned int wdt_tclk;
22ac9232	42	static unsigned long wdt_status;
6d0f0dfd	43	static spinlock_t wdt_lock;
22ac9232 SB	44
	45	static void wdt_enable(void)
	46	{
	47	u32 reg;
	48
6d0f0dfd WVS	49	spin_lock(&wdt_lock);
6d0f0dfd WVS	50
22ac9232	51	/* Set watchdog duration */
9e058d4f	52	writel(wdt_tclk * heartbeat, WDT_VAL);
22ac9232 SB	53
	54	/* Clear watchdog timer interrupt */
	55	reg = readl(BRIDGE_CAUSE);
	56	reg &= ~WDT_INT_REQ;
	57	writel(reg, BRIDGE_CAUSE);
	58
	59	/* Enable watchdog timer */
	60	reg = readl(TIMER_CTRL);
	61	reg \|= WDT_EN;
	62	writel(reg, TIMER_CTRL);
	63
	64	/* Enable reset on watchdog */
	65	reg = readl(CPU_RESET_MASK);
	66	reg \|= WDT_RESET;
	67	writel(reg, CPU_RESET_MASK);
6d0f0dfd WVS	68
6d0f0dfd WVS	69	spin_unlock(&wdt_lock);
22ac9232 SB	70	}
	71
	72	static void wdt_disable(void)
	73	{
	74	u32 reg;
	75
6d0f0dfd WVS	76	spin_lock(&wdt_lock);
6d0f0dfd WVS	77
22ac9232 SB	78	/* Disable reset on watchdog */
	79	reg = readl(CPU_RESET_MASK);
	80	reg &= ~WDT_RESET;
	81	writel(reg, CPU_RESET_MASK);
	82
	83	/* Disable watchdog timer */
	84	reg = readl(TIMER_CTRL);
	85	reg &= ~WDT_EN;
	86	writel(reg, TIMER_CTRL);
6d0f0dfd WVS	87
	88	spin_unlock(&wdt_lock);
	89	}
	90
	91	static int orion5x_wdt_get_timeleft(int *time_left)
	92	{
	93	spin_lock(&wdt_lock);
9e058d4f	94	*time_left = readl(WDT_VAL) / wdt_tclk;
6d0f0dfd WVS	95	spin_unlock(&wdt_lock);
6d0f0dfd WVS	96	return 0;
22ac9232 SB	97	}
	98
	99	static int orion5x_wdt_open(struct inode inode, struct file file)
	100	{
	101	if (test_and_set_bit(WDT_IN_USE, &wdt_status))
	102	return -EBUSY;
	103	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	104	wdt_enable();
	105	return nonseekable_open(inode, file);
	106	}
	107
22ac9232 SB	108	static ssize_t orion5x_wdt_write(struct file file, const char data,
	109	size_t len, loff_t *ppos)
	110	{
	111	if (len) {
	112	if (!nowayout) {
	113	size_t i;
	114
	115	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	116	for (i = 0; i != len; i++) {
	117	char c;
	118
	119	if (get_user(c, data + i))
	120	return -EFAULT;
	121	if (c == 'V')
	122	set_bit(WDT_OK_TO_CLOSE, &wdt_status);
	123	}
	124	}
	125	wdt_enable();
	126	}
	127	return len;
	128	}
	129
	130	static struct watchdog_info ident = {
	131	.options = WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT \|
	132	WDIOF_KEEPALIVEPING,
	133	.identity = "Orion5x Watchdog",
	134	};
	135
	136
	137	static long orion5x_wdt_ioctl(struct file *file, unsigned int cmd,
	138	unsigned long arg)
	139	{
	140	int ret = -ENOTTY;
	141	int time;
	142
	143	switch (cmd) {
	144	case WDIOC_GETSUPPORT:
	145	ret = copy_to_user((struct watchdog_info *)arg, &ident,
	146	sizeof(ident)) ? -EFAULT : 0;
	147	break;
	148
	149	case WDIOC_GETSTATUS:
	150	case WDIOC_GETBOOTSTATUS:
	151	ret = put_user(0, (int *)arg);
	152	break;
	153
	154	case WDIOC_KEEPALIVE:
	155	wdt_enable();
	156	ret = 0;
	157	break;
	158
	159	case WDIOC_SETTIMEOUT:
	160	ret = get_user(time, (int *)arg);
	161	if (ret)
	162	break;
	163
9e058d4f	164	if (time <= 0 \|\| time > wdt_max_duration) {
22ac9232 SB	165	ret = -EINVAL;
	166	break;
	167	}
	168	heartbeat = time;
	169	wdt_enable();
	170	/* Fall through */
	171
	172	case WDIOC_GETTIMEOUT:
	173	ret = put_user(heartbeat, (int *)arg);
	174	break;
	175
	176	case WDIOC_GETTIMELEFT:
	177	if (orion5x_wdt_get_timeleft(&time)) {
	178	ret = -EINVAL;
	179	break;
	180	}
	181	ret = put_user(time, (int *)arg);
	182	break;
	183	}
	184	return ret;
	185	}
	186
	187	static int orion5x_wdt_release(struct inode inode, struct file file)
	188	{
	189	if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
	190	wdt_disable();
	191	else
	192	printk(KERN_CRIT "WATCHDOG: Device closed unexpectedly - "
	193	"timer will not stop\n");
	194	clear_bit(WDT_IN_USE, &wdt_status);
	195	clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
	196
	197	return 0;
	198	}
	199
	200
	201	static const struct file_operations orion5x_wdt_fops = {
	202	.owner = THIS_MODULE,
	203	.llseek = no_llseek,
	204	.write = orion5x_wdt_write,
	205	.unlocked_ioctl = orion5x_wdt_ioctl,
	206	.open = orion5x_wdt_open,
	207	.release = orion5x_wdt_release,
	208	};
	209
	210	static struct miscdevice orion5x_wdt_miscdev = {
	211	.minor = WATCHDOG_MINOR,
	212	.name = "watchdog",
	213	.fops = &orion5x_wdt_fops,
	214	};
	215
9e058d4f	216	static int __devinit orion5x_wdt_probe(struct platform_device *pdev)
22ac9232	217	{
9e058d4f	218	struct orion5x_wdt_platform_data *pdata = pdev->dev.platform_data;
22ac9232 SB	219	int ret;
22ac9232 SB	220
9e058d4f TR	221	if (pdata) {
	222	wdt_tclk = pdata->tclk;
	223	} else {
	224	printk(KERN_ERR "Orion5x Watchdog misses platform data\n");
	225	return -ENODEV;
	226	}
	227
	228	if (orion5x_wdt_miscdev.parent)
	229	return -EBUSY;
	230	orion5x_wdt_miscdev.parent = &pdev->dev;
	231
	232	wdt_max_duration = WDT_MAX_CYCLE_COUNT / wdt_tclk;
	233	if (heartbeat <= 0 \|\| heartbeat > wdt_max_duration)
	234	heartbeat = wdt_max_duration;
6d0f0dfd	235
22ac9232	236	ret = misc_register(&orion5x_wdt_miscdev);
9e058d4f TR	237	if (ret)
	238	return ret;
	239
	240	printk(KERN_INFO "Orion5x Watchdog Timer: Initial timeout %d sec%s\n",
	241	heartbeat, nowayout ? ", nowayout" : "");
	242	return 0;
	243	}
	244
	245	static int __devexit orion5x_wdt_remove(struct platform_device *pdev)
	246	{
	247	int ret;
	248
	249	if (test_bit(WDT_IN_USE, &wdt_status)) {
	250	wdt_disable();
	251	clear_bit(WDT_IN_USE, &wdt_status);
	252	}
	253
	254	ret = misc_deregister(&orion5x_wdt_miscdev);
	255	if (!ret)
	256	orion5x_wdt_miscdev.parent = NULL;
22ac9232 SB	257
	258	return ret;
	259	}
	260
9e058d4f TR	261	static struct platform_driver orion5x_wdt_driver = {
	262	.probe = orion5x_wdt_probe,
	263	.remove = __devexit_p(orion5x_wdt_remove),
	264	.driver = {
	265	.owner = THIS_MODULE,
	266	.name = "orion5x_wdt",
	267	},
	268	};
	269
	270	static int __init orion5x_wdt_init(void)
	271	{
	272	spin_lock_init(&wdt_lock);
	273	return platform_driver_register(&orion5x_wdt_driver);
	274	}
	275
22ac9232 SB	276	static void __exit orion5x_wdt_exit(void)
22ac9232 SB	277	{
9e058d4f	278	platform_driver_unregister(&orion5x_wdt_driver);
22ac9232 SB	279	}
	280
	281	module_init(orion5x_wdt_init);
	282	module_exit(orion5x_wdt_exit);
	283
	284	MODULE_AUTHOR("Sylver Bruneau <sylver.bruneau@googlemail.com>");
	285	MODULE_DESCRIPTION("Orion5x Processor Watchdog");
	286
	287	module_param(heartbeat, int, 0);
9e058d4f	288	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds");
22ac9232 SB	289
	290	module_param(nowayout, int, 0);
	291	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
	292
	293	MODULE_LICENSE("GPL");
	294	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);