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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 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/moduleparam.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/miscdevice.h> | |
16 | #include <linux/watchdog.h> | |
17 | #include <linux/ioport.h> | |
18 | #include <linux/notifier.h> | |
19 | #include <linux/reboot.h> | |
20 | #include <linux/init.h> | |
21 | #include <linux/fs.h> | |
22 | #include <linux/pci.h> | |
23 | #include <linux/uaccess.h> | |
24 | #include <linux/io.h> | |
25 | ||
26 | #define WATCHDOG_NAME "ALi_M1535" | |
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 DEFINE_SPINLOCK(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, | |
40 | "Watchdog timeout in seconds. (0 < timeout < 18000, default=" | |
41 | __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); | |
42 | ||
43 | static bool nowayout = WATCHDOG_NOWAYOUT; | |
44 | module_param(nowayout, bool, 0); | |
45 | MODULE_PARM_DESC(nowayout, | |
46 | "Watchdog cannot be stopped once started (default=" | |
47 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
48 | ||
49 | /* | |
50 | * ali_start - start watchdog countdown | |
51 | * | |
52 | * Starts the timer running providing the timer has a counter | |
53 | * configuration set. | |
54 | */ | |
55 | ||
56 | static void ali_start(void) | |
57 | { | |
58 | u32 val; | |
59 | ||
60 | spin_lock(&ali_lock); | |
61 | ||
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); | |
66 | ||
67 | spin_unlock(&ali_lock); | |
68 | } | |
69 | ||
70 | /* | |
71 | * ali_stop - stop the timer countdown | |
72 | * | |
73 | * Stop the ALi watchdog countdown | |
74 | */ | |
75 | ||
76 | static void ali_stop(void) | |
77 | { | |
78 | u32 val; | |
79 | ||
80 | spin_lock(&ali_lock); | |
81 | ||
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); | |
86 | ||
87 | spin_unlock(&ali_lock); | |
88 | } | |
89 | ||
90 | /* | |
91 | * ali_keepalive - send a keepalive to the watchdog | |
92 | * | |
93 | * Send a keepalive to the timer (actually we restart the timer). | |
94 | */ | |
95 | ||
96 | static void ali_keepalive(void) | |
97 | { | |
98 | ali_start(); | |
99 | } | |
100 | ||
101 | /* | |
102 | * ali_settimer - compute the timer reload value | |
103 | * @t: time in seconds | |
104 | * | |
105 | * Computes the timeout values needed | |
106 | */ | |
107 | ||
108 | static int ali_settimer(int t) | |
109 | { | |
110 | if (t < 0) | |
111 | return -EINVAL; | |
112 | else if (t < 60) | |
113 | ali_timeout_bits = t|(1 << 6); | |
114 | else if (t < 3600) | |
115 | ali_timeout_bits = (t / 60)|(1 << 7); | |
116 | else if (t < 18000) | |
117 | ali_timeout_bits = (t / 300)|(1 << 6)|(1 << 7); | |
118 | else | |
119 | 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 | |
150 | magic character five months ago... */ | |
151 | ali_expect_release = 0; | |
152 | ||
153 | /* scan to see whether or not we got | |
154 | the magic character */ | |
155 | for (i = 0; i != len; i++) { | |
156 | char c; | |
157 | if (get_user(c, data + i)) | |
158 | return -EFAULT; | |
159 | if (c == 'V') | |
160 | ali_expect_release = 42; | |
161 | } | |
162 | } | |
163 | ||
164 | /* someone wrote to us, we should reload the timer */ | |
165 | ali_start(); | |
166 | } | |
167 | return len; | |
168 | } | |
169 | ||
170 | /* | |
171 | * ali_ioctl - handle watchdog ioctls | |
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 long ali_ioctl(struct file *file, unsigned int cmd, unsigned long arg) | |
181 | { | |
182 | void __user *argp = (void __user *)arg; | |
183 | int __user *p = argp; | |
184 | static const struct watchdog_info ident = { | |
185 | .options = WDIOF_KEEPALIVEPING | | |
186 | WDIOF_SETTIMEOUT | | |
187 | WDIOF_MAGICCLOSE, | |
188 | .firmware_version = 0, | |
189 | .identity = "ALi M1535 WatchDog Timer", | |
190 | }; | |
191 | ||
192 | switch (cmd) { | |
193 | case WDIOC_GETSUPPORT: | |
194 | return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; | |
195 | ||
196 | case WDIOC_GETSTATUS: | |
197 | case WDIOC_GETBOOTSTATUS: | |
198 | return put_user(0, p); | |
199 | case WDIOC_SETOPTIONS: | |
200 | { | |
201 | int new_options, retval = -EINVAL; | |
202 | ||
203 | if (get_user(new_options, p)) | |
204 | return -EFAULT; | |
205 | if (new_options & WDIOS_DISABLECARD) { | |
206 | ali_stop(); | |
207 | retval = 0; | |
208 | } | |
209 | if (new_options & WDIOS_ENABLECARD) { | |
210 | ali_start(); | |
211 | retval = 0; | |
212 | } | |
213 | return retval; | |
214 | } | |
215 | case WDIOC_KEEPALIVE: | |
216 | ali_keepalive(); | |
217 | return 0; | |
218 | case WDIOC_SETTIMEOUT: | |
219 | { | |
220 | int new_timeout; | |
221 | if (get_user(new_timeout, p)) | |
222 | return -EFAULT; | |
223 | if (ali_settimer(new_timeout)) | |
224 | return -EINVAL; | |
225 | ali_keepalive(); | |
226 | /* Fall */ | |
227 | } | |
228 | case WDIOC_GETTIMEOUT: | |
229 | return put_user(timeout, p); | |
230 | default: | |
231 | return -ENOTTY; | |
232 | } | |
233 | } | |
234 | ||
235 | /* | |
236 | * ali_open - handle open of ali watchdog | |
237 | * @inode: inode from VFS | |
238 | * @file: file from VFS | |
239 | * | |
240 | * Open the ALi watchdog device. Ensure only one person opens it | |
241 | * at a time. Also start the watchdog running. | |
242 | */ | |
243 | ||
244 | static int ali_open(struct inode *inode, struct file *file) | |
245 | { | |
246 | /* /dev/watchdog can only be opened once */ | |
247 | if (test_and_set_bit(0, &ali_is_open)) | |
248 | return -EBUSY; | |
249 | ||
250 | /* Activate */ | |
251 | ali_start(); | |
252 | return nonseekable_open(inode, file); | |
253 | } | |
254 | ||
255 | /* | |
256 | * ali_release - close an ALi watchdog | |
257 | * @inode: inode from VFS | |
258 | * @file: file from VFS | |
259 | * | |
260 | * Close the ALi watchdog device. Actual shutdown of the timer | |
261 | * only occurs if the magic sequence has been set. | |
262 | */ | |
263 | ||
264 | static int ali_release(struct inode *inode, struct file *file) | |
265 | { | |
266 | /* | |
267 | * Shut off the timer. | |
268 | */ | |
269 | if (ali_expect_release == 42) | |
270 | ali_stop(); | |
271 | else { | |
272 | pr_crit("Unexpected close, not stopping watchdog!\n"); | |
273 | ali_keepalive(); | |
274 | } | |
275 | clear_bit(0, &ali_is_open); | |
276 | ali_expect_release = 0; | |
277 | return 0; | |
278 | } | |
279 | ||
280 | /* | |
281 | * ali_notify_sys - System down notifier | |
282 | * | |
283 | * Notifier for system down | |
284 | */ | |
285 | ||
286 | ||
287 | static int ali_notify_sys(struct notifier_block *this, | |
288 | unsigned long code, void *unused) | |
289 | { | |
290 | if (code == SYS_DOWN || code == SYS_HALT) | |
291 | ali_stop(); /* Turn the WDT off */ | |
292 | return NOTIFY_DONE; | |
293 | } | |
294 | ||
295 | /* | |
296 | * Data for PCI driver interface | |
297 | * | |
298 | * This data only exists for exporting the supported | |
299 | * PCI ids via MODULE_DEVICE_TABLE. We do not actually | |
300 | * register a pci_driver, because someone else might one day | |
301 | * want to register another driver on the same PCI id. | |
302 | */ | |
303 | ||
304 | static const struct pci_device_id ali_pci_tbl[] __used = { | |
305 | { PCI_VENDOR_ID_AL, 0x1533, PCI_ANY_ID, PCI_ANY_ID,}, | |
306 | { PCI_VENDOR_ID_AL, 0x1535, PCI_ANY_ID, PCI_ANY_ID,}, | |
307 | { 0, }, | |
308 | }; | |
309 | MODULE_DEVICE_TABLE(pci, ali_pci_tbl); | |
310 | ||
311 | /* | |
312 | * ali_find_watchdog - find a 1535 and 7101 | |
313 | * | |
314 | * Scans the PCI hardware for a 1535 series bridge and matching 7101 | |
315 | * watchdog device. This may be overtight but it is better to be safe | |
316 | */ | |
317 | ||
318 | static int __init ali_find_watchdog(void) | |
319 | { | |
320 | struct pci_dev *pdev; | |
321 | u32 wdog; | |
322 | ||
323 | /* Check for a 1533/1535 series bridge */ | |
324 | pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1535, NULL); | |
325 | if (pdev == NULL) | |
326 | pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x1533, NULL); | |
327 | if (pdev == NULL) | |
328 | return -ENODEV; | |
329 | pci_dev_put(pdev); | |
330 | ||
331 | /* Check for the a 7101 PMU */ | |
332 | pdev = pci_get_device(PCI_VENDOR_ID_AL, 0x7101, NULL); | |
333 | if (pdev == NULL) | |
334 | return -ENODEV; | |
335 | ||
336 | if (pci_enable_device(pdev)) { | |
337 | pci_dev_put(pdev); | |
338 | return -EIO; | |
339 | } | |
340 | ||
341 | ali_pci = pdev; | |
342 | ||
343 | /* | |
344 | * Initialize the timer bits | |
345 | */ | |
346 | pci_read_config_dword(pdev, 0xCC, &wdog); | |
347 | ||
348 | /* Timer bits */ | |
349 | wdog &= ~0x3F; | |
350 | /* Issued events */ | |
351 | wdog &= ~((1 << 27)|(1 << 26)|(1 << 25)|(1 << 24)); | |
352 | /* No monitor bits */ | |
353 | wdog &= ~((1 << 16)|(1 << 13)|(1 << 12)|(1 << 11)|(1 << 10)|(1 << 9)); | |
354 | ||
355 | pci_write_config_dword(pdev, 0xCC, wdog); | |
356 | ||
357 | return 0; | |
358 | } | |
359 | ||
360 | /* | |
361 | * Kernel Interfaces | |
362 | */ | |
363 | ||
364 | static const struct file_operations ali_fops = { | |
365 | .owner = THIS_MODULE, | |
366 | .llseek = no_llseek, | |
367 | .write = ali_write, | |
368 | .unlocked_ioctl = ali_ioctl, | |
369 | .open = ali_open, | |
370 | .release = ali_release, | |
371 | }; | |
372 | ||
373 | static struct miscdevice ali_miscdev = { | |
374 | .minor = WATCHDOG_MINOR, | |
375 | .name = "watchdog", | |
376 | .fops = &ali_fops, | |
377 | }; | |
378 | ||
379 | static struct notifier_block ali_notifier = { | |
380 | .notifier_call = ali_notify_sys, | |
381 | }; | |
382 | ||
383 | /* | |
384 | * watchdog_init - module initialiser | |
385 | * | |
386 | * Scan for a suitable watchdog and if so initialize it. Return an error | |
387 | * if we cannot, the error causes the module to unload | |
388 | */ | |
389 | ||
390 | static int __init watchdog_init(void) | |
391 | { | |
392 | int ret; | |
393 | ||
394 | /* Check whether or not the hardware watchdog is there */ | |
395 | if (ali_find_watchdog() != 0) | |
396 | return -ENODEV; | |
397 | ||
398 | /* Check that the timeout value is within it's range; | |
399 | if not reset to the default */ | |
400 | if (timeout < 1 || timeout >= 18000) { | |
401 | timeout = WATCHDOG_TIMEOUT; | |
402 | pr_info("timeout value must be 0 < timeout < 18000, using %d\n", | |
403 | timeout); | |
404 | } | |
405 | ||
406 | /* Calculate the watchdog's timeout */ | |
407 | ali_settimer(timeout); | |
408 | ||
409 | ret = register_reboot_notifier(&ali_notifier); | |
410 | if (ret != 0) { | |
411 | pr_err("cannot register reboot notifier (err=%d)\n", ret); | |
412 | goto out; | |
413 | } | |
414 | ||
415 | ret = misc_register(&ali_miscdev); | |
416 | if (ret != 0) { | |
417 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", | |
418 | WATCHDOG_MINOR, ret); | |
419 | goto unreg_reboot; | |
420 | } | |
421 | ||
422 | pr_info("initialized. timeout=%d sec (nowayout=%d)\n", | |
423 | timeout, nowayout); | |
424 | ||
425 | out: | |
426 | return ret; | |
427 | unreg_reboot: | |
428 | unregister_reboot_notifier(&ali_notifier); | |
429 | goto out; | |
430 | } | |
431 | ||
432 | /* | |
433 | * watchdog_exit - module de-initialiser | |
434 | * | |
435 | * Called while unloading a successfully installed watchdog module. | |
436 | */ | |
437 | ||
438 | static void __exit watchdog_exit(void) | |
439 | { | |
440 | /* Stop the timer before we leave */ | |
441 | ali_stop(); | |
442 | ||
443 | /* Deregister */ | |
444 | misc_deregister(&ali_miscdev); | |
445 | unregister_reboot_notifier(&ali_notifier); | |
446 | pci_dev_put(ali_pci); | |
447 | } | |
448 | ||
449 | module_init(watchdog_init); | |
450 | module_exit(watchdog_exit); | |
451 | ||
452 | MODULE_AUTHOR("Alan Cox"); | |
453 | MODULE_DESCRIPTION("ALi M1535 PMU Watchdog Timer driver"); | |
454 | MODULE_LICENSE("GPL"); |