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1da177e4 LT |
1 | /* |
2 | * Watchdog for the 7101 PMU version found in the ALi M1535 chipsets | |
3 | * | |
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. | |
8 | */ | |
9 | ||
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/fs.h> | |
20 | #include <linux/pci.h> | |
21 | ||
22 | #include <asm/uaccess.h> | |
23 | #include <asm/io.h> | |
24 | ||
25 | #define WATCHDOG_NAME "ALi_M1535" | |
26 | #define PFX WATCHDOG_NAME ": " | |
27 | #define WATCHDOG_TIMEOUT 60 /* 60 sec default timeout */ | |
28 | ||
29 | /* internal variables */ | |
30 | static unsigned long ali_is_open; | |
31 | static char ali_expect_release; | |
32 | static struct pci_dev *ali_pci; | |
33 | static u32 ali_timeout_bits; /* stores the computed timeout */ | |
34 | static spinlock_t ali_lock; /* Guards the hardware */ | |
35 | ||
36 | /* module parameters */ | |
37 | static int timeout = WATCHDOG_TIMEOUT; | |
38 | module_param(timeout, int, 0); | |
39 | MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. (0<timeout<18000, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
40 | ||
41 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | |
42 | static int nowayout = 1; | |
43 | #else | |
44 | static int nowayout = 0; | |
45 | #endif | |
46 | ||
47 | module_param(nowayout, int, 0); | |
48 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | |
49 | ||
50 | /* | |
51 | * ali_start - start watchdog countdown | |
52 | * | |
53 | * Starts the timer running providing the timer has a counter | |
54 | * configuration set. | |
55 | */ | |
56 | ||
57 | static void ali_start(void) | |
58 | { | |
59 | u32 val; | |
60 | ||
61 | spin_lock(&ali_lock); | |
62 | ||
63 | pci_read_config_dword(ali_pci, 0xCC, &val); | |
64 | val &= ~0x3F; /* Mask count */ | |
65 | val |= (1<<25) | ali_timeout_bits; | |
66 | pci_write_config_dword(ali_pci, 0xCC, val); | |
67 | ||
68 | spin_unlock(&ali_lock); | |
69 | } | |
70 | ||
71 | /* | |
72 | * ali_stop - stop the timer countdown | |
73 | * | |
74 | * Stop the ALi watchdog countdown | |
75 | */ | |
76 | ||
77 | static void ali_stop(void) | |
78 | { | |
79 | u32 val; | |
80 | ||
81 | spin_lock(&ali_lock); | |
82 | ||
83 | pci_read_config_dword(ali_pci, 0xCC, &val); | |
84 | val &= ~0x3F; /* Mask count to zero (disabled) */ | |
85 | val &= ~(1<<25);/* and for safety mask the reset enable */ | |
86 | pci_write_config_dword(ali_pci, 0xCC, val); | |
87 | ||
88 | spin_unlock(&ali_lock); | |
89 | } | |
90 | ||
91 | /* | |
92 | * ali_keepalive - send a keepalive to the watchdog | |
93 | * | |
94 | * Send a keepalive to the timer (actually we restart the timer). | |
95 | */ | |
96 | ||
97 | static void ali_keepalive(void) | |
98 | { | |
99 | ali_start(); | |
100 | } | |
101 | ||
102 | /* | |
103 | * ali_settimer - compute the timer reload value | |
104 | * @t: time in seconds | |
105 | * | |
106 | * Computes the timeout values needed | |
107 | */ | |
108 | ||
109 | static int ali_settimer(int t) | |
110 | { | |
111 | if(t < 0) | |
112 | return -EINVAL; | |
113 | else if(t < 60) | |
114 | ali_timeout_bits = t|(1<<6); | |
115 | else if(t < 3600) | |
116 | ali_timeout_bits = (t/60)|(1<<7); | |
117 | else if(t < 18000) | |
118 | ali_timeout_bits = (t/300)|(1<<6)|(1<<7); | |
119 | else return -EINVAL; | |
120 | ||
121 | timeout = t; | |
122 | return 0; | |
123 | } | |
124 | ||
125 | /* | |
126 | * /dev/watchdog handling | |
127 | */ | |
128 | ||
129 | /* | |
130 | * ali_write - writes to ALi watchdog | |
131 | * @file: file from VFS | |
132 | * @data: user address of data | |
133 | * @len: length of data | |
134 | * @ppos: pointer to the file offset | |
135 | * | |
136 | * Handle a write to the ALi watchdog. Writing to the file pings | |
137 | * the watchdog and resets it. Writing the magic 'V' sequence allows | |
138 | * the next close to turn off the watchdog. | |
139 | */ | |
140 | ||
141 | static ssize_t ali_write(struct file *file, const char __user *data, | |
142 | size_t len, loff_t * ppos) | |
143 | { | |
144 | /* See if we got the magic character 'V' and reload the timer */ | |
145 | if (len) { | |
146 | if (!nowayout) { | |
147 | size_t i; | |
148 | ||
149 | /* note: just in case someone wrote the magic character | |
150 | * five months ago... */ | |
151 | ali_expect_release = 0; | |
152 | ||
153 | /* scan to see whether or not we got the magic character */ | |
154 | for (i = 0; i != len; i++) { | |
155 | char c; | |
156 | if(get_user(c, data+i)) | |
157 | return -EFAULT; | |
158 | if (c == 'V') | |
159 | ali_expect_release = 42; | |
160 | } | |
161 | } | |
162 | ||
163 | /* someone wrote to us, we should reload the timer */ | |
164 | ali_start(); | |
165 | } | |
166 | return len; | |
167 | } | |
168 | ||
169 | /* | |
170 | * ali_ioctl - handle watchdog ioctls | |
171 | * @inode: VFS inode | |
172 | * @file: VFS file pointer | |
173 | * @cmd: ioctl number | |
174 | * @arg: arguments to the ioctl | |
175 | * | |
176 | * Handle the watchdog ioctls supported by the ALi driver. Really | |
177 | * we want an extension to enable irq ack monitoring and the like | |
178 | */ | |
179 | ||
180 | static int ali_ioctl(struct inode *inode, struct file *file, | |
181 | unsigned int cmd, unsigned long arg) | |
182 | { | |
183 | void __user *argp = (void __user *)arg; | |
184 | int __user *p = argp; | |
185 | static struct watchdog_info ident = { | |
186 | .options = WDIOF_KEEPALIVEPING | | |
187 | WDIOF_SETTIMEOUT | | |
188 | WDIOF_MAGICCLOSE, | |
189 | .firmware_version = 0, | |
190 | .identity = "ALi M1535 WatchDog Timer", | |
191 | }; | |
192 | ||
193 | switch (cmd) { | |
194 | case WDIOC_GETSUPPORT: | |
195 | return copy_to_user(argp, &ident, | |
196 | sizeof (ident)) ? -EFAULT : 0; | |
197 | ||
198 | case WDIOC_GETSTATUS: | |
199 | case WDIOC_GETBOOTSTATUS: | |
200 | return put_user(0, p); | |
201 | ||
202 | case WDIOC_KEEPALIVE: | |
203 | ali_keepalive(); | |
204 | return 0; | |
205 | ||
206 | case WDIOC_SETOPTIONS: | |
207 | { | |
208 | int new_options, retval = -EINVAL; | |
209 | ||
210 | if (get_user (new_options, p)) | |
211 | return -EFAULT; | |
212 | ||
213 | if (new_options & WDIOS_DISABLECARD) { | |
214 | ali_stop(); | |
215 | retval = 0; | |
216 | } | |
217 | ||
218 | if (new_options & WDIOS_ENABLECARD) { | |
219 | ali_start(); | |
220 | retval = 0; | |
221 | } | |
222 | ||
223 | return retval; | |
224 | } | |
225 | ||
226 | case WDIOC_SETTIMEOUT: | |
227 | { | |
228 | int new_timeout; | |
229 | ||
230 | if (get_user(new_timeout, p)) | |
231 | return -EFAULT; | |
232 | ||
233 | if (ali_settimer(new_timeout)) | |
234 | return -EINVAL; | |
235 | ||
236 | ali_keepalive(); | |
237 | /* Fall */ | |
238 | } | |
239 | ||
240 | case WDIOC_GETTIMEOUT: | |
241 | return put_user(timeout, p); | |
242 | ||
243 | default: | |
244 | return -ENOIOCTLCMD; | |
245 | } | |
246 | } | |
247 | ||
248 | /* | |
249 | * ali_open - handle open of ali watchdog | |
250 | * @inode: inode from VFS | |
251 | * @file: file from VFS | |
252 | * | |
253 | * Open the ALi watchdog device. Ensure only one person opens it | |
254 | * at a time. Also start the watchdog running. | |
255 | */ | |
256 | ||
257 | static int ali_open(struct inode *inode, struct file *file) | |
258 | { | |
259 | /* /dev/watchdog can only be opened once */ | |
260 | if (test_and_set_bit(0, &ali_is_open)) | |
261 | return -EBUSY; | |
262 | ||
263 | /* Activate */ | |
264 | ali_start(); | |
265 | return nonseekable_open(inode, file); | |
266 | } | |
267 | ||
268 | /* | |
269 | * ali_release - close an ALi watchdog | |
270 | * @inode: inode from VFS | |
271 | * @file: file from VFS | |
272 | * | |
273 | * Close the ALi watchdog device. Actual shutdown of the timer | |
274 | * only occurs if the magic sequence has been set. | |
275 | */ | |
276 | ||
277 | static int ali_release(struct inode *inode, struct file *file) | |
278 | { | |
279 | /* | |
280 | * Shut off the timer. | |
281 | */ | |
282 | if (ali_expect_release == 42) { | |
283 | ali_stop(); | |
284 | } else { | |
285 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | |
286 | ali_keepalive(); | |
287 | } | |
288 | clear_bit(0, &ali_is_open); | |
289 | ali_expect_release = 0; | |
290 | return 0; | |
291 | } | |
292 | ||
293 | /* | |
294 | * ali_notify_sys - System down notifier | |
295 | * | |
296 | * Notifier for system down | |
297 | */ | |
298 | ||
299 | ||
300 | static int ali_notify_sys(struct notifier_block *this, unsigned long code, void *unused) | |
301 | { | |
302 | if (code==SYS_DOWN || code==SYS_HALT) { | |
303 | /* Turn the WDT off */ | |
304 | ali_stop(); | |
305 | } | |
306 | ||
307 | return NOTIFY_DONE; | |
308 | } | |
309 | ||
310 | /* | |
311 | * Data for PCI driver interface | |
312 | * | |
313 | * This data only exists for exporting the supported | |
314 | * PCI ids via MODULE_DEVICE_TABLE. We do not actually | |
315 | * register a pci_driver, because someone else might one day | |
316 | * want to register another driver on the same PCI id. | |
317 | */ | |
318 | ||
319 | static struct pci_device_id ali_pci_tbl[] = { | |
320 | { PCI_VENDOR_ID_AL, 1535, PCI_ANY_ID, PCI_ANY_ID,}, | |
321 | { 0, }, | |
322 | }; | |
323 | MODULE_DEVICE_TABLE(pci, ali_pci_tbl); | |
324 | ||
325 | /* | |
326 | * ali_find_watchdog - find a 1535 and 7101 | |
327 | * | |
328 | * Scans the PCI hardware for a 1535 series bridge and matching 7101 | |
329 | * watchdog device. This may be overtight but it is better to be safe | |
330 | */ | |
331 | ||
332 | static int __init ali_find_watchdog(void) | |
333 | { | |
334 | struct pci_dev *pdev; | |
335 | u32 wdog; | |
336 | ||
337 | /* Check for a 1535 series bridge */ | |
338 | pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x1535, NULL); | |
339 | if(pdev == NULL) | |
340 | return -ENODEV; | |
341 | ||
342 | /* Check for the a 7101 PMU */ | |
343 | pdev = pci_find_device(PCI_VENDOR_ID_AL, 0x7101, NULL); | |
344 | if(pdev == NULL) | |
345 | return -ENODEV; | |
346 | ||
347 | if(pci_enable_device(pdev)) | |
348 | return -EIO; | |
349 | ||
350 | ali_pci = pdev; | |
351 | ||
352 | /* | |
353 | * Initialize the timer bits | |
354 | */ | |
355 | pci_read_config_dword(pdev, 0xCC, &wdog); | |
356 | ||
357 | wdog &= ~0x3F; /* Timer bits */ | |
358 | wdog &= ~((1<<27)|(1<<26)|(1<<25)|(1<<24)); /* Issued events */ | |
359 | wdog &= ~((1<<16)|(1<<13)|(1<<12)|(1<<11)|(1<<10)|(1<<9)); /* No monitor bits */ | |
360 | ||
361 | pci_write_config_dword(pdev, 0xCC, wdog); | |
362 | ||
363 | return 0; | |
364 | } | |
365 | ||
366 | /* | |
367 | * Kernel Interfaces | |
368 | */ | |
369 | ||
370 | static struct file_operations ali_fops = { | |
371 | .owner = THIS_MODULE, | |
372 | .llseek = no_llseek, | |
373 | .write = ali_write, | |
374 | .ioctl = ali_ioctl, | |
375 | .open = ali_open, | |
376 | .release = ali_release, | |
377 | }; | |
378 | ||
379 | static struct miscdevice ali_miscdev = { | |
380 | .minor = WATCHDOG_MINOR, | |
381 | .name = "watchdog", | |
382 | .fops = &ali_fops, | |
383 | }; | |
384 | ||
385 | static struct notifier_block ali_notifier = { | |
386 | .notifier_call = ali_notify_sys, | |
387 | }; | |
388 | ||
389 | /* | |
390 | * watchdog_init - module initialiser | |
391 | * | |
392 | * Scan for a suitable watchdog and if so initialize it. Return an error | |
393 | * if we cannot, the error causes the module to unload | |
394 | */ | |
395 | ||
396 | static int __init watchdog_init(void) | |
397 | { | |
398 | int ret; | |
399 | ||
400 | spin_lock_init(&ali_lock); | |
401 | ||
402 | /* Check whether or not the hardware watchdog is there */ | |
403 | if (ali_find_watchdog() != 0) { | |
404 | return -ENODEV; | |
405 | } | |
406 | ||
407 | /* Check that the timeout value is within it's range ; if not reset to the default */ | |
408 | if (timeout < 1 || timeout >= 18000) { | |
409 | timeout = WATCHDOG_TIMEOUT; | |
410 | printk(KERN_INFO PFX "timeout value must be 0<timeout<18000, using %d\n", | |
411 | timeout); | |
412 | } | |
413 | ||
414 | /* Calculate the watchdog's timeout */ | |
415 | ali_settimer(timeout); | |
416 | ||
417 | ret = misc_register(&ali_miscdev); | |
418 | if (ret != 0) { | |
419 | printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | |
420 | WATCHDOG_MINOR, ret); | |
421 | goto out; | |
422 | } | |
423 | ||
424 | ret = register_reboot_notifier(&ali_notifier); | |
425 | if (ret != 0) { | |
426 | printk(KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | |
427 | ret); | |
428 | goto unreg_miscdev; | |
429 | } | |
430 | ||
431 | printk(KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n", | |
432 | timeout, nowayout); | |
433 | ||
434 | out: | |
435 | return ret; | |
436 | unreg_miscdev: | |
437 | misc_deregister(&ali_miscdev); | |
438 | goto out; | |
439 | } | |
440 | ||
441 | /* | |
442 | * watchdog_exit - module de-initialiser | |
443 | * | |
444 | * Called while unloading a successfully installed watchdog module. | |
445 | */ | |
446 | ||
447 | static void __exit watchdog_exit(void) | |
448 | { | |
449 | /* Stop the timer before we leave */ | |
450 | ali_stop(); | |
451 | ||
452 | /* Deregister */ | |
453 | unregister_reboot_notifier(&ali_notifier); | |
454 | misc_deregister(&ali_miscdev); | |
455 | } | |
456 | ||
457 | module_init(watchdog_init); | |
458 | module_exit(watchdog_exit); | |
459 | ||
460 | MODULE_AUTHOR("Alan Cox"); | |
461 | MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver"); | |
462 | MODULE_LICENSE("GPL"); | |
463 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |