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
ali_start(void)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
ali_stop(void)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
ali_keepalive(void)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
ali_settimer(int t)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
ali_write(struct file * file,const char __user * data,size_t len,loff_t * ppos)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
ali_ioctl(struct file * file,unsigned int cmd,unsigned long arg)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 }
227 /* fall through */
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
ali_open(struct inode * inode,struct file * file)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
ali_release(struct inode * inode,struct file * file)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
ali_notify_sys(struct notifier_block * this,unsigned long code,void * unused)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
ali_find_watchdog(void)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
watchdog_init(void)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
watchdog_exit(void)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");
455
