2 * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
10 #include <linux/module.h>
11 #include <linux/moduleparam.h>
12 #include <linux/types.h>
13 #include <linux/miscdevice.h>
14 #include <linux/watchdog.h>
15 #include <linux/ioport.h>
16 #include <linux/notifier.h>
17 #include <linux/reboot.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
21 #include <asm/uaccess.h>
24 #define WATCHDOG_NAME "ALi_M1535"
25 #define PFX WATCHDOG_NAME ": "
26 #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */
28 /* internal variables */
29 static unsigned long ali_is_open;
30 static char ali_expect_release;
31 static struct pci_dev *ali_pci;
32 static u32 ali_timeout_bits; /* stores the computed timeout */
33 static spinlock_t ali_lock; /* Guards the hardware */
35 /* module parameters */
36 static int timeout = WATCHDOG_TIMEOUT;
37 module_param(timeout, int, 0);
38 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (0<timeout<18000, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
40 #ifdef CONFIG_WATCHDOG_NOWAYOUT
41 static int nowayout = 1;
43 static int nowayout = 0;
46 module_param(nowayout, int, 0);
47 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
50 * ali_start - start watchdog countdown
52 * Starts the timer running providing the timer has a counter
56 static void ali_start(void)
62 pci_read_config_dword(ali_pci, 0xCC, &val);
63 val &= ~0x3F; /* Mask count */
64 val |= (1<<25) | ali_timeout_bits;
65 pci_write_config_dword(ali_pci, 0xCC, val);
67 spin_unlock(&ali_lock);
71 * ali_stop - stop the timer countdown
73 * Stop the ALi watchdog countdown
76 static void ali_stop(void)
82 pci_read_config_dword(ali_pci, 0xCC, &val);
83 val &= ~0x3F; /* Mask count to zero (disabled) */
84 val &= ~(1<<25);/* and for safety mask the reset enable */
85 pci_write_config_dword(ali_pci, 0xCC, val);
87 spin_unlock(&ali_lock);
91 * ali_keepalive - send a keepalive to the watchdog
93 * Send a keepalive to the timer (actually we restart the timer).
96 static void ali_keepalive(void)
102 * ali_settimer - compute the timer reload value
103 * @t: time in seconds
105 * Computes the timeout values needed
108 static int ali_settimer(int t)
113 ali_timeout_bits = t|(1<<6);
115 ali_timeout_bits = (t/60)|(1<<7);
117 ali_timeout_bits = (t/300)|(1<<6)|(1<<7);
125 * /dev/watchdog handling
129 * ali_write - writes to ALi watchdog
130 * @file: file from VFS
131 * @data: user address of data
132 * @len: length of data
133 * @ppos: pointer to the file offset
135 * Handle a write to the ALi watchdog. Writing to the file pings
136 * the watchdog and resets it. Writing the magic 'V' sequence allows
137 * the next close to turn off the watchdog.
140 static ssize_t ali_write(struct file *file, const char *data,
141 size_t len, loff_t * ppos)
143 /* Can't seek (pwrite) on this device */
144 if (ppos != &file->f_pos)
147 /* See if we got the magic character 'V' and reload the timer */
152 /* note: just in case someone wrote the magic character
153 * five months ago... */
154 ali_expect_release = 0;
156 /* scan to see whether or not we got the magic character */
157 for (i = 0; i != len; i++) {
159 if(get_user(c, data+i))
162 ali_expect_release = 42;
166 /* someone wrote to us, we should reload the timer */
173 * ali_ioctl - handle watchdog ioctls
175 * @file: VFS file pointer
177 * @arg: arguments to the ioctl
179 * Handle the watchdog ioctls supported by the ALi driver. Really
180 * we want an extension to enable irq ack monitoring and the like
183 static int ali_ioctl(struct inode *inode, struct file *file,
184 unsigned int cmd, unsigned long arg)
186 static struct watchdog_info ident = {
187 .options = WDIOF_KEEPALIVEPING |
190 .firmware_version = 0,
191 .identity = "ALi M1535 WatchDog Timer",
195 case WDIOC_GETSUPPORT:
196 return copy_to_user((struct watchdog_info *) arg, &ident,
197 sizeof (ident)) ? -EFAULT : 0;
199 case WDIOC_GETSTATUS:
200 case WDIOC_GETBOOTSTATUS:
201 return put_user(0, (int *) arg);
203 case WDIOC_KEEPALIVE:
207 case WDIOC_SETOPTIONS:
209 int new_options, retval = -EINVAL;
211 if (get_user (new_options, (int *) arg))
214 if (new_options & WDIOS_DISABLECARD) {
219 if (new_options & WDIOS_ENABLECARD) {
227 case WDIOC_SETTIMEOUT:
231 if (get_user(new_timeout, (int *) arg))
234 if (ali_settimer(new_timeout))
241 case WDIOC_GETTIMEOUT:
242 return put_user(timeout, (int *)arg);
250 * ali_open - handle open of ali watchdog
251 * @inode: inode from VFS
252 * @file: file from VFS
254 * Open the ALi watchdog device. Ensure only one person opens it
255 * at a time. Also start the watchdog running.
258 static int ali_open(struct inode *inode, struct file *file)
260 /* /dev/watchdog can only be opened once */
261 if (test_and_set_bit(0, &ali_is_open))
270 * ali_release - close an ALi watchdog
271 * @inode: inode from VFS
272 * @file: file from VFS
274 * Close the ALi watchdog device. Actual shutdown of the timer
275 * only occurs if the magic sequence has been set.
278 static int ali_release(struct inode *inode, struct file *file)
281 * Shut off the timer.
283 if (ali_expect_release == 42) {
286 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
289 clear_bit(0, &ali_is_open);
290 ali_expect_release = 0;
295 * ali_notify_sys - System down notifier
297 * Notifier for system down
301 static int ali_notify_sys(struct notifier_block *this, unsigned long code, void *unused)
303 if (code==SYS_DOWN || code==SYS_HALT) {
304 /* Turn the WDT off */
312 * Data for PCI driver interface
314 * This data only exists for exporting the supported
315 * PCI ids via MODULE_DEVICE_TABLE. We do not actually
316 * register a pci_driver, because someone else might one day
317 * want to register another driver on the same PCI id.
320 static struct pci_device_id ali_pci_tbl[] = {
321 { PCI_VENDOR_ID_AL, 1535, PCI_ANY_ID, PCI_ANY_ID,},
324 MODULE_DEVICE_TABLE(pci, ali_pci_tbl);
327 * ali_find_watchdog - find a 1535 and 7101
329 * Scans the PCI hardware for a 1535 series bridge and matching 7101
330 * watchdog device. This may be overtight but it is better to be safe
333 static int __init ali_find_watchdog(void)
335 struct pci_dev *pdev;
338 /* Check for a 1535 series bridge */
339 pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x1535, NULL);
343 /* Check for the a 7101 PMU */
344 pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x7101, NULL);
348 if(pci_enable_device(pdev))
354 * Initialize the timer bits
356 pci_read_config_dword(pdev, 0xCC, &wdog);
358 wdog &= ~0x3F; /* Timer bits */
359 wdog &= ~((1<<27)|(1<<26)|(1<<25)|(1<<24)); /* Issued events */
360 wdog &= ~((1<<16)|(1<<13)|(1<<12)|(1<<11)|(1<<10)|(1<<9)); /* No monitor bits */
362 pci_write_config_dword(pdev, 0xCC, wdog);
371 static struct file_operations ali_fops = {
372 .owner = THIS_MODULE,
377 .release = ali_release,
380 static struct miscdevice ali_miscdev = {
381 .minor = WATCHDOG_MINOR,
386 static struct notifier_block ali_notifier = {
387 .notifier_call = ali_notify_sys,
391 * watchdog_init - module initialiser
393 * Scan for a suitable watchdog and if so initialize it. Return an error
394 * if we cannot, the error causes the module to unload
397 static int __init watchdog_init(void)
401 spin_lock_init(&ali_lock);
403 /* Check whether or not the hardware watchdog is there */
404 if (ali_find_watchdog() != 0) {
408 /* Check that the timeout value is within it's range ; if not reset to the default */
409 if (timeout < 1 || timeout >= 18000) {
410 timeout = WATCHDOG_TIMEOUT;
411 printk(KERN_INFO PFX "timeout value must be 0<timeout<18000, using %d\n",
415 /* Calculate the watchdog's timeout */
416 ali_settimer(timeout);
418 ret = misc_register(&ali_miscdev);
420 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
421 WATCHDOG_MINOR, ret);
425 ret = register_reboot_notifier(&ali_notifier);
427 printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n",
432 printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
438 misc_deregister(&ali_miscdev);
443 * watchdog_exit - module de-initialiser
445 * Called while unloading a successfully installed watchdog module.
448 static void __exit watchdog_exit(void)
450 /* Stop the timer before we leave */
454 unregister_reboot_notifier(&ali_notifier);
455 misc_deregister(&ali_miscdev);
458 module_init(watchdog_init);
459 module_exit(watchdog_exit);
461 MODULE_AUTHOR("Alan Cox");
462 MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver");
463 MODULE_LICENSE("GPL");
464 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);