2 * ALi M7101 PMU Computer Watchdog Timer driver
4 * Based on w83877f_wdt.c by Scott Jennings <linuxdrivers@oro.net>
5 * and the Cobalt kernel WDT timer driver by Tim Hockin
6 * <thockin@cobaltnet.com>
8 * (c)2002 Steve Hill <steve@navaho.co.uk>
10 * This WDT driver is different from most other Linux WDT
11 * drivers in that the driver will ping the watchdog by itself,
12 * because this particular WDT has a very short timeout (1.6
13 * seconds) and it would be insane to count on any userspace
14 * daemon always getting scheduled within that time frame.
17 #include <linux/module.h>
18 #include <linux/moduleparam.h>
19 #include <linux/types.h>
20 #include <linux/timer.h>
21 #include <linux/miscdevice.h>
22 #include <linux/watchdog.h>
23 #include <linux/ioport.h>
24 #include <linux/notifier.h>
25 #include <linux/reboot.h>
26 #include <linux/init.h>
28 #include <linux/pci.h>
31 #include <asm/uaccess.h>
32 #include <asm/system.h>
34 #define OUR_NAME "alim7101_wdt"
35 #define PFX OUR_NAME ": "
37 #define WDT_ENABLE 0x9C
38 #define WDT_DISABLE 0x8C
40 #define ALI_7101_WDT 0x92
41 #define ALI_WDT_ARM 0x01
44 * We're going to use a 1 second timeout.
45 * If we reset the watchdog every ~250ms we should be safe. */
47 #define WDT_INTERVAL (HZ/4+1)
50 * We must not require too good response from the userspace daemon.
51 * Here we require the userspace daemon to send us a heartbeat
52 * char to /dev/watchdog every 30 seconds.
55 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
56 static int timeout = WATCHDOG_TIMEOUT; /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
57 module_param(timeout, int, 0);
58 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (1<=timeout<=3600, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
60 static void wdt_timer_ping(unsigned long);
61 static struct timer_list timer;
62 static unsigned long next_heartbeat;
63 static unsigned long wdt_is_open;
64 static char wdt_expect_close;
65 static struct pci_dev *alim7101_pmu;
67 #ifdef CONFIG_WATCHDOG_NOWAYOUT
68 static int nowayout = 1;
70 static int nowayout = 0;
73 module_param(nowayout, int, 0);
74 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
80 static void wdt_timer_ping(unsigned long data)
82 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
83 * we agree to ping the WDT
87 if(time_before(jiffies, next_heartbeat))
89 /* Ping the WDT (this is actually a disarm/arm sequence) */
90 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
91 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
92 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
94 printk(KERN_WARNING PFX "Heartbeat lost! Will not ping the watchdog\n");
96 /* Re-set the timer interval */
97 timer.expires = jiffies + WDT_INTERVAL;
105 static void wdt_change(int writeval)
109 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
110 if (writeval == WDT_ENABLE)
111 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp | ALI_WDT_ARM));
113 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
116 static void wdt_startup(void)
118 next_heartbeat = jiffies + (timeout * HZ);
120 /* We must enable before we kick off the timer in case the timer
121 occurs as we ping it */
123 wdt_change(WDT_ENABLE);
125 /* Start the timer */
126 timer.expires = jiffies + WDT_INTERVAL;
130 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
133 static void wdt_turnoff(void)
136 del_timer_sync(&timer);
137 wdt_change(WDT_DISABLE);
138 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
141 static void wdt_keepalive(void)
144 next_heartbeat = jiffies + (timeout * HZ);
148 * /dev/watchdog handling
151 static ssize_t fop_write(struct file * file, const char * buf, size_t count, loff_t * ppos)
154 if(ppos != &file->f_pos)
157 /* See if we got the magic character 'V' and reload the timer */
162 /* note: just in case someone wrote the magic character
163 * five months ago... */
164 wdt_expect_close = 0;
167 for (ofs = 0; ofs != count; ofs++) {
169 if (get_user(c, buf+ofs))
172 wdt_expect_close = 42;
175 /* someone wrote to us, we should restart timer */
181 static int fop_open(struct inode * inode, struct file * file)
183 /* Just in case we're already talking to someone... */
184 if(test_and_set_bit(0, &wdt_is_open))
186 /* Good, fire up the show */
191 static int fop_close(struct inode * inode, struct file * file)
193 if(wdt_expect_close == 42)
196 /* wim: shouldn't there be a: del_timer(&timer); */
197 printk(KERN_CRIT PFX "device file closed unexpectedly. Will not stop the WDT!\n");
199 clear_bit(0, &wdt_is_open);
200 wdt_expect_close = 0;
204 static int fop_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
206 static struct watchdog_info ident =
208 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
209 .firmware_version = 1,
210 .identity = "ALiM7101",
215 case WDIOC_GETSUPPORT:
216 return copy_to_user((struct watchdog_info *)arg, &ident, sizeof(ident))?-EFAULT:0;
217 case WDIOC_GETSTATUS:
218 case WDIOC_GETBOOTSTATUS:
219 return put_user(0, (int *)arg);
220 case WDIOC_KEEPALIVE:
223 case WDIOC_SETOPTIONS:
225 int new_options, retval = -EINVAL;
227 if(get_user(new_options, (int *)arg))
230 if(new_options & WDIOS_DISABLECARD) {
235 if(new_options & WDIOS_ENABLECARD) {
242 case WDIOC_SETTIMEOUT:
246 if(get_user(new_timeout, (int *)arg))
249 if(new_timeout < 1 || new_timeout > 3600) /* arbitrary upper limit */
252 timeout = new_timeout;
256 case WDIOC_GETTIMEOUT:
257 return put_user(timeout, (int *)arg);
263 static struct file_operations wdt_fops = {
272 static struct miscdevice wdt_miscdev = {
273 .minor=WATCHDOG_MINOR,
279 * Notifier for system down
282 static int wdt_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
284 if (code==SYS_DOWN || code==SYS_HALT)
287 if (code==SYS_RESTART) {
289 * Cobalt devices have no way of rebooting themselves other than
290 * getting the watchdog to pull reset, so we restart the watchdog on
291 * reboot with no heartbeat
293 wdt_change(WDT_ENABLE);
294 printk(KERN_INFO PFX "Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second.\n");
300 * The WDT needs to learn about soft shutdowns in order to
301 * turn the timebomb registers off.
304 static struct notifier_block wdt_notifier=
306 .notifier_call = wdt_notify_sys,
309 static void __exit alim7101_wdt_unload(void)
313 misc_deregister(&wdt_miscdev);
314 unregister_reboot_notifier(&wdt_notifier);
317 static int __init alim7101_wdt_init(void)
320 struct pci_dev *ali1543_south;
323 printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
324 alim7101_pmu = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,NULL);
326 printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
330 /* Set the WDT in the PMU to 1 second */
331 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
333 ali1543_south = pci_find_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533, NULL);
334 if (!ali1543_south) {
335 printk(KERN_INFO PFX "ALi 1543 South-Bridge not present - WDT not set\n");
338 pci_read_config_byte(ali1543_south, 0x5e, &tmp);
339 if ((tmp & 0x1e) != 0x12) {
340 printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
344 if(timeout < 1 || timeout > 3600) /* arbitrary upper limit */
346 timeout = WATCHDOG_TIMEOUT;
347 printk(KERN_INFO PFX "timeout value must be 1<=x<=3600, using %d\n",
352 timer.function = wdt_timer_ping;
355 rc = misc_register(&wdt_miscdev);
357 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
358 wdt_miscdev.minor, rc);
362 rc = register_reboot_notifier(&wdt_notifier);
364 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
366 goto err_out_miscdev;
369 printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
374 misc_deregister(&wdt_miscdev);
379 module_init(alim7101_wdt_init);
380 module_exit(alim7101_wdt_unload);
382 MODULE_AUTHOR("Steve Hill");
383 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
384 MODULE_LICENSE("GPL");
385 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);