[net-next-2.6.git] / drivers / watchdog / pika_wdt.c

/*
 * PIKA FPGA based Watchdog Timer
 *
 * Copyright (c) 2008 PIKA Technologies
 *   Sean MacLennan <smaclennan@pikatech.com>
 */

#include <linux/init.h>
#include <linux/errno.h>
#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/reboot.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/bitops.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/of_platform.h>

#define DRV_NAME "PIKA-WDT"
#define PFX DRV_NAME ": "

/* Hardware timeout in seconds */
#define WDT_HW_TIMEOUT 2

/* Timer heartbeat (500ms) */
#define WDT_TIMEOUT	(HZ/2)

/* User land timeout */
#define WDT_HEARTBEAT 15
static int heartbeat = WDT_HEARTBEAT;
module_param(heartbeat, int, 0);
MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
	"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");

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 struct {
	void __iomem *fpga;
	unsigned long next_heartbeat;	/* the next_heartbeat for the timer */
	unsigned long open;
	char expect_close;
	int bootstatus;
	struct timer_list timer;	/* The timer that pings the watchdog */
} pikawdt_private;

static struct watchdog_info ident = {
	.identity	= DRV_NAME,
	.options	= WDIOF_CARDRESET |
			  WDIOF_SETTIMEOUT |
			  WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE,
};

/*
 * Reload the watchdog timer.  (ie, pat the watchdog)
 */
static inline void pikawdt_reset(void)
{
	/* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
	 * Bit 7,    WTCHDG_EN: When set to 1, the watchdog timer is enabled.
	 *           Once enabled, it cannot be disabled. The watchdog can be
	 *           kicked by performing any write access to the reset
	 *           control register (this register).
	 * Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
	 *           seconds. Valid ranges are 1 to 15 seconds. The value can
	 *           be modified dynamically.
	 */
	unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
	/* enable with max timeout - 15 seconds */
	reset |= (1 << 7) + (WDT_HW_TIMEOUT << 8);
	out_be32(pikawdt_private.fpga + 0x14, reset);
}

/*
 * Timer tick
 */
static void pikawdt_ping(unsigned long data)
{
	if (time_before(jiffies, pikawdt_private.next_heartbeat) ||
			(!nowayout && !pikawdt_private.open)) {
		pikawdt_reset();
		mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
	} else
		printk(KERN_CRIT PFX "I will reset your machine !\n");
}


static void pikawdt_keepalive(void)
{
	pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
}

static void pikawdt_start(void)
{
	pikawdt_keepalive();
	mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
}

/*
 * Watchdog device is opened, and watchdog starts running.
 */
static int pikawdt_open(struct inode *inode, struct file *file)
{
	/* /dev/watchdog can only be opened once */
	if (test_and_set_bit(0, &pikawdt_private.open))
		return -EBUSY;

	pikawdt_start();

	return nonseekable_open(inode, file);
}

/*
 * Close the watchdog device.
 */
static int pikawdt_release(struct inode *inode, struct file *file)
{
	/* stop internal ping */
	if (!pikawdt_private.expect_close)
		del_timer(&pikawdt_private.timer);

	clear_bit(0, &pikawdt_private.open);
	pikawdt_private.expect_close = 0;
	return 0;
}

/*
 * Pat the watchdog whenever device is written to.
 */
static ssize_t pikawdt_write(struct file *file, const char __user *data,
			     size_t len, loff_t *ppos)
{
	if (!len)
		return 0;

	/* Scan for magic character */
	if (!nowayout) {
		size_t i;

		pikawdt_private.expect_close = 0;

		for (i = 0; i < len; i++) {
			char c;
			if (get_user(c, data + i))
				return -EFAULT;
			if (c == 'V') {
				pikawdt_private.expect_close = 42;
				break;
			}
		}
	}

	pikawdt_keepalive();

	return len;
}

/*
 * Handle commands from user-space.
 */
static long pikawdt_ioctl(struct file *file,
		unsigned int cmd, unsigned long arg)
{
	void __user *argp = (void __user *)arg;
	int __user *p = argp;
	int new_value;

	switch (cmd) {
	case WDIOC_GETSUPPORT:
		return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;

	case WDIOC_GETSTATUS:
		return put_user(0, p);

	case WDIOC_GETBOOTSTATUS:
		return put_user(pikawdt_private.bootstatus, p);

	case WDIOC_KEEPALIVE:
		pikawdt_keepalive();
		return 0;

	case WDIOC_SETTIMEOUT:
		if (get_user(new_value, p))
			return -EFAULT;

		heartbeat = new_value;
		pikawdt_keepalive();

		return put_user(new_value, p);  /* return current value */

	case WDIOC_GETTIMEOUT:
		return put_user(heartbeat, p);
	}
	return -ENOTTY;
}


static const struct file_operations pikawdt_fops = {
	.owner		= THIS_MODULE,
	.llseek		= no_llseek,
	.open		= pikawdt_open,
	.release	= pikawdt_release,
	.write		= pikawdt_write,
	.unlocked_ioctl	= pikawdt_ioctl,
};

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

static int __init pikawdt_init(void)
{
	struct device_node *np;
	void __iomem *fpga;
	static u32 post1;
	int ret;

	np = of_find_compatible_node(NULL, NULL, "pika,fpga");
	if (np == NULL) {
		printk(KERN_ERR PFX "Unable to find fpga.\n");
		return -ENOENT;
	}

	pikawdt_private.fpga = of_iomap(np, 0);
	of_node_put(np);
	if (pikawdt_private.fpga == NULL) {
		printk(KERN_ERR PFX "Unable to map fpga.\n");
		return -ENOMEM;
	}

	ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;

	/* POST information is in the sd area. */
	np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
	if (np == NULL) {
		printk(KERN_ERR PFX "Unable to find fpga-sd.\n");
		ret = -ENOENT;
		goto out;
	}

	fpga = of_iomap(np, 0);
	of_node_put(np);
	if (fpga == NULL) {
		printk(KERN_ERR PFX "Unable to map fpga-sd.\n");
		ret = -ENOMEM;
		goto out;
	}

	/* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
	 * Bit 31,   WDOG: Set to 1 when the last reset was caused by a watchdog
	 *           timeout.
	 */
	post1 = in_be32(fpga + 0x40);
	if (post1 & 0x80000000)
		pikawdt_private.bootstatus = WDIOF_CARDRESET;

	iounmap(fpga);

	setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);

	ret = misc_register(&pikawdt_miscdev);
	if (ret) {
		printk(KERN_ERR PFX "Unable to register miscdev.\n");
		goto out;
	}

	printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
							heartbeat, nowayout);
	return 0;

out:
	iounmap(pikawdt_private.fpga);
	return ret;
}

static void __exit pikawdt_exit(void)
{
	misc_deregister(&pikawdt_miscdev);

	iounmap(pikawdt_private.fpga);
}

module_init(pikawdt_init);
module_exit(pikawdt_exit);

MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
MODULE_LICENSE("GPL");
MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
Commit	Line	Data
618efba9 SM	1	/*
	2	* PIKA FPGA based Watchdog Timer
	3	*
	4	* Copyright (c) 2008 PIKA Technologies
	5	* Sean MacLennan <smaclennan@pikatech.com>
	6	*/
	7
	8	#include <linux/init.h>
	9	#include <linux/errno.h>
	10	#include <linux/module.h>
	11	#include <linux/moduleparam.h>
	12	#include <linux/types.h>
	13	#include <linux/kernel.h>
	14	#include <linux/fs.h>
	15	#include <linux/miscdevice.h>
	16	#include <linux/watchdog.h>
	17	#include <linux/reboot.h>
	18	#include <linux/jiffies.h>
	19	#include <linux/timer.h>
	20	#include <linux/bitops.h>
	21	#include <linux/uaccess.h>
	22	#include <linux/io.h>
	23	#include <linux/of_platform.h>
	24
	25	#define DRV_NAME "PIKA-WDT"
	26	#define PFX DRV_NAME ": "
	27
	28	/* Hardware timeout in seconds */
	29	#define WDT_HW_TIMEOUT 2
	30
	31	/* Timer heartbeat (500ms) */
	32	#define WDT_TIMEOUT (HZ/2)
	33
	34	/* User land timeout */
	35	#define WDT_HEARTBEAT 15
	36	static int heartbeat = WDT_HEARTBEAT;
	37	module_param(heartbeat, int, 0);
	38	MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. "
	39	"(default = " __MODULE_STRING(WDT_HEARTBEAT) ")");
	40
	41	static int nowayout = WATCHDOG_NOWAYOUT;
	42	module_param(nowayout, int, 0);
	43	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
	44	"(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
	45
	46	static struct {
	47	void __iomem *fpga;
	48	unsigned long next_heartbeat; /* the next_heartbeat for the timer */
	49	unsigned long open;
	50	char expect_close;
	51	int bootstatus;
	52	struct timer_list timer; /* The timer that pings the watchdog */
	53	} pikawdt_private;
	54
35c79780	55	static struct watchdog_info ident = {
618efba9 SM	56	.identity = DRV_NAME,
	57	.options = WDIOF_CARDRESET \|
	58	WDIOF_SETTIMEOUT \|
	59	WDIOF_KEEPALIVEPING \|
	60	WDIOF_MAGICCLOSE,
	61	};
	62
	63	/*
	64	* Reload the watchdog timer. (ie, pat the watchdog)
	65	*/
	66	static inline void pikawdt_reset(void)
	67	{
	68	/* -- FPGA: Reset Control Register (32bit R/W) (Offset: 0x14) --
	69	* Bit 7, WTCHDG_EN: When set to 1, the watchdog timer is enabled.
	70	* Once enabled, it cannot be disabled. The watchdog can be
	71	* kicked by performing any write access to the reset
	72	* control register (this register).
	73	* Bit 8-11, WTCHDG_TIMEOUT_SEC: Sets the watchdog timeout value in
	74	* seconds. Valid ranges are 1 to 15 seconds. The value can
	75	* be modified dynamically.
	76	*/
	77	unsigned reset = in_be32(pikawdt_private.fpga + 0x14);
	78	/* enable with max timeout - 15 seconds */
	79	reset \|= (1 << 7) + (WDT_HW_TIMEOUT << 8);
	80	out_be32(pikawdt_private.fpga + 0x14, reset);
	81	}
	82
	83	/*
	84	* Timer tick
	85	*/
	86	static void pikawdt_ping(unsigned long data)
	87	{
	88	if (time_before(jiffies, pikawdt_private.next_heartbeat) \|\|
	89	(!nowayout && !pikawdt_private.open)) {
	90	pikawdt_reset();
	91	mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
	92	} else
	93	printk(KERN_CRIT PFX "I will reset your machine !\n");
	94	}
	95
	96
	97	static void pikawdt_keepalive(void)
	98	{
	99	pikawdt_private.next_heartbeat = jiffies + heartbeat * HZ;
	100	}
	101
	102	static void pikawdt_start(void)
	103	{
	104	pikawdt_keepalive();
	105	mod_timer(&pikawdt_private.timer, jiffies + WDT_TIMEOUT);
	106	}
	107
	108	/*
	109	* Watchdog device is opened, and watchdog starts running.
	110	*/
	111	static int pikawdt_open(struct inode inode, struct file file)
	112	{
	113	/* /dev/watchdog can only be opened once */
	114	if (test_and_set_bit(0, &pikawdt_private.open))
	115	return -EBUSY;
	116
	117	pikawdt_start();
	118
	119	return nonseekable_open(inode, file);
120	}
121
122	/*
123	* Close the watchdog device.
124	*/
125	static int pikawdt_release(struct inode inode, struct file file)
126	{
127	/* stop internal ping */
128	if (!pikawdt_private.expect_close)
129	del_timer(&pikawdt_private.timer);
130
131	clear_bit(0, &pikawdt_private.open);
132	pikawdt_private.expect_close = 0;
133	return 0;
134	}
135
136	/*
137	* Pat the watchdog whenever device is written to.
138	*/
139	static ssize_t pikawdt_write(struct file file, const char __user data,
140	size_t len, loff_t *ppos)
141	{
142	if (!len)
143	return 0;
144
145	/* Scan for magic character */
146	if (!nowayout) {
147	size_t i;
148
149	pikawdt_private.expect_close = 0;
150
151	for (i = 0; i < len; i++) {
152	char c;
153	if (get_user(c, data + i))
154	return -EFAULT;
155	if (c == 'V') {
156	pikawdt_private.expect_close = 42;
157	break;
158	}
159	}
160	}
161
162	pikawdt_keepalive();
163
164	return len;
165	}
166
167	/*
168	* Handle commands from user-space.
169	*/
170	static long pikawdt_ioctl(struct file *file,
171	unsigned int cmd, unsigned long arg)
172	{
173	void __user argp = (void __user )arg;
174	int __user *p = argp;
175	int new_value;
176
177	switch (cmd) {
178	case WDIOC_GETSUPPORT:
179	return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
180
181	case WDIOC_GETSTATUS:
182	return put_user(0, p);
183
184	case WDIOC_GETBOOTSTATUS:
185	return put_user(pikawdt_private.bootstatus, p);
186
187	case WDIOC_KEEPALIVE:
188	pikawdt_keepalive();
189	return 0;
190
191	case WDIOC_SETTIMEOUT:
192	if (get_user(new_value, p))
193	return -EFAULT;
194
195	heartbeat = new_value;
196	pikawdt_keepalive();
197
198	return put_user(new_value, p); /* return current value */
199
200	case WDIOC_GETTIMEOUT:
201	return put_user(heartbeat, p);
202	}
203	return -ENOTTY;
204	}
205
206
207	static const struct file_operations pikawdt_fops = {
208	.owner = THIS_MODULE,
209	.llseek = no_llseek,
210	.open = pikawdt_open,
211	.release = pikawdt_release,
212	.write = pikawdt_write,
213	.unlocked_ioctl = pikawdt_ioctl,
214	};
215
216	static struct miscdevice pikawdt_miscdev = {
217	.minor = WATCHDOG_MINOR,
218	.name = "watchdog",
219	.fops = &pikawdt_fops,
220	};
221
222	static int __init pikawdt_init(void)
223	{
224	struct device_node *np;
225	void __iomem *fpga;
226	static u32 post1;
227	int ret;
228
229	np = of_find_compatible_node(NULL, NULL, "pika,fpga");
230	if (np == NULL) {
231	printk(KERN_ERR PFX "Unable to find fpga.\n");
232	return -ENOENT;
233	}
234
235	pikawdt_private.fpga = of_iomap(np, 0);
236	of_node_put(np);
237	if (pikawdt_private.fpga == NULL) {
238	printk(KERN_ERR PFX "Unable to map fpga.\n");
239	return -ENOMEM;
240	}
241
242	ident.firmware_version = in_be32(pikawdt_private.fpga + 0x1c) & 0xffff;
243
244	/* POST information is in the sd area. */
245	np = of_find_compatible_node(NULL, NULL, "pika,fpga-sd");
246	if (np == NULL) {
247	printk(KERN_ERR PFX "Unable to find fpga-sd.\n");
248	ret = -ENOENT;
249	goto out;
250	}
251
252	fpga = of_iomap(np, 0);
253	of_node_put(np);
254	if (fpga == NULL) {
255	printk(KERN_ERR PFX "Unable to map fpga-sd.\n");
256	ret = -ENOMEM;
257	goto out;
258	}
259
260	/* -- FPGA: POST Test Results Register 1 (32bit R/W) (Offset: 0x4040) --
261	* Bit 31, WDOG: Set to 1 when the last reset was caused by a watchdog
262	* timeout.
263	*/
264	post1 = in_be32(fpga + 0x40);
265	if (post1 & 0x80000000)
266	pikawdt_private.bootstatus = WDIOF_CARDRESET;
267
268	iounmap(fpga);
269
270	setup_timer(&pikawdt_private.timer, pikawdt_ping, 0);
271
272	ret = misc_register(&pikawdt_miscdev);
273	if (ret) {
274	printk(KERN_ERR PFX "Unable to register miscdev.\n");
275	goto out;
276	}
277
278	printk(KERN_INFO PFX "initialized. heartbeat=%d sec (nowayout=%d)\n",
279	heartbeat, nowayout);
280	return 0;
281
282	out:
283	iounmap(pikawdt_private.fpga);
284	return ret;
285	}
286
287	static void __exit pikawdt_exit(void)
288	{
289	misc_deregister(&pikawdt_miscdev);
290
291	iounmap(pikawdt_private.fpga);
292	}
293
294	module_init(pikawdt_init);
295	module_exit(pikawdt_exit);
296
297	MODULE_AUTHOR("Sean MacLennan <smaclennan@pikatech.com>");
298	MODULE_DESCRIPTION("PIKA FPGA based Watchdog Timer");
299	MODULE_LICENSE("GPL");
300	MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
301