Merge http://linux-watchdog.bkbits.net/linux-2.5-watchdog

into iguana.be:/home/wim/BitKeeper/projects/linux-2.5-watchdog

drivers/char/watchdog/sc520_wdt.c

 /*
- *	AMD Elan SC520 processor Watchdog Timer driver for Linux 2.4.x
+ *	AMD Elan SC520 processor Watchdog Timer driver
  *
  *      Based on acquirewdt.c by Alan Cox,
- *           and sbc60xxwdt.c by Jakob Oestergaard <jakob@ostenfeld.dk>
+ *           and sbc60xxwdt.c by Jakob Oestergaard <jakob@unthought.net>
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License
@@ -24,20 +24,21 @@
  *	-	Used ioremap/writew/readw
  *	-	Added NOWAYOUT support
  *
- *  Theory of operation:
- *  A Watchdog Timer (WDT) is a hardware circuit that can 
- *  reset the computer system in case of a software fault.
- *  You probably knew that already.
- *
- *  Usually a userspace daemon will notify the kernel WDT driver
- *  via the /proc/watchdog special device file that userspace is
- *  still alive, at regular intervals.  When such a notification
- *  occurs, the driver will usually tell the hardware watchdog
- *  that everything is in order, and that the watchdog should wait
- *  for yet another little while to reset the system.
- *  If userspace fails (RAM error, kernel bug, whatever), the
- *  notifications cease to occur, and the hardware watchdog will
- *  reset the system (causing a reboot) after the timeout occurs.
+ *     4/12 - 2002 Changes by Rob Radez <rob@osinvestor.com>
+ *     -       Change comments
+ *     -       Eliminate fop_llseek
+ *     -       Change CONFIG_WATCHDOG_NOWAYOUT semantics
+ *     -       Add KERN_* tags to printks
+ *     -       fix possible wdt_is_open race
+ *     -       Report proper capabilities in watchdog_info
+ *     -       Add WDIOC_{GETSTATUS, GETBOOTSTATUS, SETTIMEOUT,
+ *             GETTIMEOUT, SETOPTIONS} ioctls
+ *     09/8 - 2003 Changes by Wim Van Sebroeck <wim@iguana.be>
+ *     -       cleanup of trailing spaces
+ *     -       added extra printk's for startup problems
+ *     -       use module_param
+ *     -       made timeout (the emulated heartbeat) a module_param
+ *     -       made the keepalive ping an internal subroutine
  *
  *  This WDT driver is different from most other Linux WDT
  *  drivers in that the driver will ping the watchdog by itself,
@@ -77,7 +78,10 @@
  * char to /dev/watchdog every 30 seconds.
  */
 
-#define WDT_HEARTBEAT (HZ * 30)
+#define WATCHDOG_TIMEOUT 30		/* 30 sec default timeout */
+static int timeout = WATCHDOG_TIMEOUT;	/* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
 
 /*
  * AMD Elan SC520 timeout value is 492us times a power of 2 (0-7)
@@ -95,6 +99,7 @@
 #define WDT_WRST_ENB 0x4000	/* [14] Watchdog Timer Reset Enable */
 
 #define OUR_NAME "sc520_wdt"
+#define PFX OUR_NAME ": "
 
 #define WRT_DOG(data) *wdtmrctl=data
 
@@ -104,7 +109,8 @@ static void wdt_timer_ping(unsigned long);
 static struct timer_list timer;
 static unsigned long next_heartbeat;
 static unsigned long wdt_is_open;
-static int wdt_expect_close;
+static char wdt_expect_close;
+static spinlock_t wdt_spinlock;
 
 #ifdef CONFIG_WATCHDOG_NOWAYOUT
 static int nowayout = 1;
@@ -115,7 +121,6 @@ static int nowayout = 0;
 module_param(nowayout, int, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
 
-static spinlock_t wdt_spinlock;
 /*
  *	Whack the dog
  */
@@ -137,7 +142,7 @@ static void wdt_timer_ping(unsigned long data)
 		timer.expires = jiffies + WDT_INTERVAL;
 		add_timer(&timer);
 	} else {
-		printk(OUR_NAME ": Heartbeat lost! Will not ping the watchdog\n");
+		printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
 	}
 }
 
@@ -165,14 +170,14 @@ static void wdt_config(int writeval)
 
 static void wdt_startup(void)
 {
-	next_heartbeat = jiffies + WDT_HEARTBEAT;
+	next_heartbeat = jiffies + (timeout * HZ);
 
 	/* Start the timer */
 	timer.expires = jiffies + WDT_INTERVAL;
 	add_timer(&timer);
 
 	wdt_config(WDT_ENB | WDT_WRST_ENB | TIMEOUT_EXPONENT);
-	printk(OUR_NAME ": Watchdog timer is now enabled.\n");  
+	printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
 }
 
 static void wdt_turnoff(void)
@@ -181,10 +186,15 @@ static void wdt_turnoff(void)
 		/* Stop the timer */
 		del_timer(&timer);
 		wdt_config(0);
-		printk(OUR_NAME ": Watchdog timer is now disabled...\n");
+		printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
 	}
 }
 
+static void wdt_keepalive(void)
+{
+	/* user land ping */
+	next_heartbeat = jiffies + (timeout * HZ);
+}
 
 /*
  * /dev/watchdog handling
@@ -196,8 +206,10 @@ static ssize_t fop_write(struct file * file, const char * buf, size_t count, lof
 	if(ppos != &file->f_pos)
 		return -ESPIPE;
 
-	/* See if we got the magic character */
+	/* See if we got the magic character 'V' and reload the timer */
 	if(count)
+	{
+		if (!nowayout)
 		{
 			size_t ofs;
 
@@ -211,47 +223,39 @@ static ssize_t fop_write(struct file * file, const char * buf, size_t count, lof
 				if (get_user(c, buf + ofs))
 					return -EFAULT;
 				if(c == 'V')
-				wdt_expect_close = 1;
+					wdt_expect_close = 42;
+			}
 		}
 
 		/* Well, anyhow someone wrote to us, we should return that favour */
-		next_heartbeat = jiffies + WDT_HEARTBEAT;
-		return 1;
+		wdt_keepalive();
 	}
-	return 0;
+	return count;
 }
 
 static int fop_open(struct inode * inode, struct file * file)
 {
-	switch(minor(inode->i_rdev)) 
-	{
-		case WATCHDOG_MINOR:
 	/* Just in case we're already talking to someone... */
 	if(test_and_set_bit(0, &wdt_is_open))
 		return -EBUSY;
-			/* Good, fire up the show */
-			wdt_startup();
 	if (nowayout)
 		__module_get(THIS_MODULE);
 
+	/* Good, fire up the show */
+	wdt_startup();
 	return 0;
-		default:
-			return -ENODEV;
-	}
 }
 
 static int fop_close(struct inode * inode, struct file * file)
 {
-	if(minor(inode->i_rdev) == WATCHDOG_MINOR) 
-	{
-		if(wdt_expect_close)
+	if(wdt_expect_close == 42)
 		wdt_turnoff();
 	else {
 		del_timer(&timer);
-			printk(OUR_NAME ": device file closed unexpectedly. Will not stop the WDT!\n");
-		}
+		printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
 	}
 	clear_bit(0, &wdt_is_open);
+	wdt_expect_close = 0;
 	return 0;
 }
 
@@ -260,9 +264,9 @@ static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 {
 	static struct watchdog_info ident=
 	{
-		.options = WDIOF_MAGICCLOSE,
+		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 		.firmware_version = 1,
-		.identity = "SC520"
+		.identity = "SC520",
 	};
 
 	switch(cmd)
@@ -271,9 +275,47 @@ static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 			return -ENOIOCTLCMD;
 		case WDIOC_GETSUPPORT:
 			return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))?-EFAULT:0;
+		case WDIOC_GETSTATUS:
+		case WDIOC_GETBOOTSTATUS:
+			return put_user(0, (int *)arg);
 		case WDIOC_KEEPALIVE:
-			next_heartbeat = jiffies + WDT_HEARTBEAT;
+			wdt_keepalive();
 			return 0;
+		case WDIOC_SETOPTIONS:
+		{
+			int new_options, retval = -EINVAL;
+
+			if(get_user(new_options, (int *)arg))
+				return -EFAULT;
+
+			if(new_options & WDIOS_DISABLECARD) {
+				wdt_turnoff();
+				retval = 0;
+			}
+
+			if(new_options & WDIOS_ENABLECARD) {
+				wdt_startup();
+				retval = 0;
+			}
+
+			return retval;
+		}
+		case WDIOC_SETTIMEOUT:
+		{
+			int new_timeout;
+
+			if(get_user(new_timeout, (int *)arg))
+				return -EFAULT;
+
+			if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
+				return -EINVAL;
+
+			timeout = new_timeout;
+			wdt_keepalive();
+			/* Fall through */
+		}
+		case WDIOC_GETTIMEOUT:
+			return put_user(timeout, (int *)arg);
 	}
 }
 
@@ -283,13 +325,13 @@ static struct file_operations wdt_fops = {
 	.write		= fop_write,
 	.open		= fop_open,
 	.release	= fop_close,
-	.ioctl		= fop_ioctl
+	.ioctl		= fop_ioctl,
 };
 
 static struct miscdevice wdt_miscdev = {
 	.minor	= WATCHDOG_MINOR,
 	.name	= "watchdog",
-	.fops	= &wdt_fops
+	.fops	= &wdt_fops,
 };
 
 /*
@@ -313,7 +355,7 @@ static struct notifier_block wdt_notifier=
 {
 	.notifier_call = wdt_notify_sys,
 	.next = NULL,
-	.priority = 0
+	.priority = 0,
 };
 
 static void __exit sc520_wdt_unload(void)
@@ -333,27 +375,42 @@ static int __init sc520_wdt_init(void)
 
 	spin_lock_init(&wdt_spinlock);
 
+	if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
+	{
+		timeout = WATCHDOG_TIMEOUT;
+		printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
+			timeout);
+	}
+
 	init_timer(&timer);
 	timer.function = wdt_timer_ping;
 	timer.data = 0;
 
 	rc = misc_register(&wdt_miscdev);
 	if (rc)
+	{
+		printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
+			wdt_miscdev.minor, rc);
 		goto err_out_region2;
+	}
 
 	rc = register_reboot_notifier(&wdt_notifier);
 	if (rc)
+	{
+		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
+			rc);
 		goto err_out_miscdev;
+	}
 
 	/* get the Base Address Register */
 	cbar = inl_p(0xfffc);
-	printk(OUR_NAME ": CBAR: 0x%08lx\n", cbar);
+	printk(KERN_INFO PFX "CBAR: 0x%08lx\n", cbar);
 	/* check if MMCR aliasing bit is set */
 	if (cbar & 0x80000000) {
-		printk(OUR_NAME ": MMCR Aliasing enabled.\n");
+		printk(KERN_INFO PFX "MMCR Aliasing enabled.\n");
 		wdtmrctl = (__u16 *)(cbar & 0x3fffffff);
 	} else {
-		printk(OUR_NAME "!!! WARNING !!!\n"
+		printk(KERN_INFO PFX "!!! WARNING !!!\n"
 		  "\t MMCR Aliasing found NOT enabled!\n"
 		  "\t Using default value of: %p\n"
 		  "\t This has not been tested!\n"
@@ -366,7 +423,8 @@ static int __init sc520_wdt_init(void)
 
 	wdtmrctl = (__u16 *)((char *)wdtmrctl + OFFS_WDTMRCTL);
 	wdtmrctl = ioremap((unsigned long)wdtmrctl, 2);
-	printk(KERN_INFO OUR_NAME ": WDT driver for SC520 initialised.\n");
+	printk(KERN_INFO PFX "WDT driver for SC520 initialised. timeout=%d sec (nowayout=%d)\n",
+		timeout,nowayout);
 
 	return 0;