/* *	ALi M7101 PMU Computer Watchdog Timer driver * *	Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net> *	and the Cobalt kernel WDT timer driver by Tim Hockin *	                                      <thockin@cobaltnet.com> * *	(c)2002 Steve Hill <steve@navaho.co.uk> * *  This WDT driver is different from most other Linux WDT *  drivers in that the driver will ping the watchdog by itself, *  because this particular WDT has a very short timeout (1.6 *  seconds) and it would be insane to count on any userspace *  daemon always getting scheduled within that time frame. */#include <linux/module.h>#include <linux/moduleparam.h>#include <linux/types.h>#include <linux/timer.h>#include <linux/miscdevice.h>#include <linux/watchdog.h>#include <linux/ioport.h>#include <linux/notifier.h>#include <linux/reboot.h>#include <linux/init.h>#include <linux/fs.h>#include <linux/pci.h>#include <asm/io.h>#include <asm/uaccess.h>#include <asm/system.h>#define OUR_NAME "alim7101_wdt"#define PFX OUR_NAME ": "#define WDT_ENABLE 0x9C#define WDT_DISABLE 0x8C#define ALI_7101_WDT    0x92#define ALI_WDT_ARM     0x01/* * We're going to use a 1 second timeout. * If we reset the watchdog every ~250ms we should be safe.  */#define WDT_INTERVAL (HZ/4+1)/* * We must not require too good response from the userspace daemon. * Here we require the userspace daemon to send us a heartbeat * char to /dev/watchdog every 30 seconds. */#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) ")");static void wdt_timer_ping(unsigned long);static struct timer_list timer;static unsigned long next_heartbeat;static unsigned long wdt_is_open;static char wdt_expect_close;static struct pci_dev *alim7101_pmu;#ifdef CONFIG_WATCHDOG_NOWAYOUTstatic int nowayout = 1;#elsestatic int nowayout = 0;#endifmodule_param(nowayout, int, 0);MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");/* *	Whack the dog */static void wdt_timer_ping(unsigned long data){	/* If we got a heartbeat pulse within the WDT_US_INTERVAL	 * we agree to ping the WDT	 */	char	tmp;	if(time_before(jiffies, next_heartbeat))	{		/* Ping the WDT (this is actually a disarm/arm sequence) */		pci_read_config_byte(alim7101_pmu, 0x92, &tmp);		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));	} else {		printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");	}	/* Re-set the timer interval */	timer.expires = jiffies + WDT_INTERVAL;	add_timer(&timer);}/* * Utility routines */static void wdt_change(int writeval){	char	tmp;	pci_read_config_byte(alim7101_pmu, 0x92, &tmp);	if (writeval == WDT_ENABLE)		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));	else		pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));}static void wdt_startup(void){	next_heartbeat = jiffies + (timeout * HZ);	/* We must enable before we kick off the timer in case the timer	   occurs as we ping it */	wdt_change(WDT_ENABLE);	/* Start the timer */	timer.expires = jiffies + WDT_INTERVAL;	add_timer(&timer);	printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");}static void wdt_turnoff(void){	/* Stop the timer */	del_timer_sync(&timer);	wdt_change(WDT_DISABLE);	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 */static ssize_t fop_write(struct file * file, const char __user * buf, size_t count, loff_t * ppos){	/* See if we got the magic character 'V' and reload the timer */	if(count) {		if (!nowayout) {			size_t ofs;			/* note: just in case someone wrote the magic character			 * five months ago... */			wdt_expect_close = 0;			/* now scan */			for (ofs = 0; ofs != count; ofs++) {				char c;				if (get_user(c, buf+ofs))					return -EFAULT;				if (c == 'V')					wdt_expect_close = 42;			}		}		/* someone wrote to us, we should restart timer */		wdt_keepalive();	}	return count;}static int fop_open(struct inode * inode, struct file * file){	/* 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();	return nonseekable_open(inode, file);}static int fop_close(struct inode * inode, struct file * file){	if(wdt_expect_close == 42)		wdt_turnoff();	else {		/* wim: shouldn't there be a: del_timer(&timer); */		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;}static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg){	void __user *argp = (void __user *)arg;	int __user *p = argp;	static struct watchdog_info ident =	{		.options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,		.firmware_version = 1,		.identity = "ALiM7101",	};	switch(cmd)	{		case WDIOC_GETSUPPORT:			return copy_to_user(argp, &ident, sizeof(ident))?-EFAULT:0;		case WDIOC_GETSTATUS:		case WDIOC_GETBOOTSTATUS:			return put_user(0, p);		case WDIOC_KEEPALIVE:			wdt_keepalive();			return 0;		case WDIOC_SETOPTIONS:		{			int new_options, retval = -EINVAL;			if(get_user(new_options, p))				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, p))				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, p);		default:			return -ENOIOCTLCMD;	}}static struct file_operations wdt_fops = {	.owner=		THIS_MODULE,	.llseek=	no_llseek,	.write=		fop_write,	.open=		fop_open,	.release=	fop_close,	.ioctl=		fop_ioctl,};static struct miscdevice wdt_miscdev = {	.minor=WATCHDOG_MINOR,	.name="watchdog",	.fops=&wdt_fops,};/* *	Notifier for system down */static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused){	if (code==SYS_DOWN || code==SYS_HALT)		wdt_turnoff();	if (code==SYS_RESTART) {		/*		 * Cobalt devices have no way of rebooting themselves other than		 * getting the watchdog to pull reset, so we restart the watchdog on		 * reboot with no heartbeat		 */		wdt_change(WDT_ENABLE);		printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");	}	return NOTIFY_DONE;}/* *	The WDT needs to learn about soft shutdowns in order to *	turn the timebomb registers off. */static struct notifier_block wdt_notifier={	.notifier_call = wdt_notify_sys,};static void __exit alim7101_wdt_unload(void){	wdt_turnoff();	/* Deregister */	misc_deregister(&wdt_miscdev);	unregister_reboot_notifier(&wdt_notifier);}static int __init alim7101_wdt_init(void){	int rc = -EBUSY;	struct pci_dev *ali1543_south;	char tmp;	printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");	alim7101_pmu = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,NULL);	if (!alim7101_pmu) {		printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");		return -EBUSY;	}	/* Set the WDT in the PMU to 1 second */	pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);	ali1543_south = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL);	if (!ali1543_south) {		printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");		return -EBUSY;	}	pci_read_config_byte(ali1543_south, 0x5e, &tmp);	if ((tmp & 0x1e) != 0x12) {		printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");		return -EBUSY;	}	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 = 1;	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;	}	rc = register_reboot_notifier(&wdt_notifier);	if (rc) {		printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",			rc);		goto err_out_miscdev;	}	printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",		timeout, nowayout);	return 0;err_out_miscdev:	misc_deregister(&wdt_miscdev);err_out:	return rc;}module_init(alim7101_wdt_init);module_exit(alim7101_wdt_unload);MODULE_AUTHOR("Steve Hill");MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");MODULE_LICENSE("GPL");MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);