1 /*
2 * ALi M7101 PMU Computer Watchdog Timer driver
3 *
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>
7 *
8 * (c)2002 Steve Hill <steve@navaho.co.uk>
9 *
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.
15 *
16 * Additions:
17 * Aug 23, 2004 - Added use_gpio module parameter for use on revision a1d PMUs
18 * found on very old cobalt hardware.
19 * -- Mike Waychison <michael.waychison@sun.com>
20 */
21
22 #include <linux/module.h>
23 #include <linux/moduleparam.h>
24 #include <linux/types.h>
25 #include <linux/timer.h>
26 #include <linux/miscdevice.h>
27 #include <linux/watchdog.h>
28 #include <linux/ioport.h>
29 #include <linux/notifier.h>
30 #include <linux/reboot.h>
31 #include <linux/init.h>
32 #include <linux/fs.h>
33 #include <linux/pci.h>
34 #include <linux/io.h>
35 #include <linux/uaccess.h>
36
37 #include <asm/system.h>
38
39 #define OUR_NAME "alim7101_wdt"
40 #define PFX OUR_NAME ": "
41
42 #define WDT_ENABLE 0x9C
43 #define WDT_DISABLE 0x8C
44
45 #define ALI_7101_WDT 0x92
46 #define ALI_7101_GPIO 0x7D
47 #define ALI_7101_GPIO_O 0x7E
48 #define ALI_WDT_ARM 0x01
49
50 /*
51 * We're going to use a 1 second timeout.
52 * If we reset the watchdog every ~250ms we should be safe. */
53
54 #define WDT_INTERVAL (HZ/4+1)
55
56 /*
57 * We must not require too good response from the userspace daemon.
58 * Here we require the userspace daemon to send us a heartbeat
59 * char to /dev/watchdog every 30 seconds.
60 */
61
62 #define WATCHDOG_TIMEOUT 30 /* 30 sec default timeout */
63 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
64 static int timeout = WATCHDOG_TIMEOUT;
65 module_param(timeout, int, 0);
66 MODULE_PARM_DESC(timeout,
67 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
68 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
69
70 static int use_gpio; /* Use the pic (for a1d revision alim7101) */
71 module_param(use_gpio, int, 0);
72 MODULE_PARM_DESC(use_gpio,
73 "Use the gpio watchdog (required by old cobalt boards).");
74
75 static void wdt_timer_ping(unsigned long);
76 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
77 static unsigned long next_heartbeat;
78 static unsigned long wdt_is_open;
79 static char wdt_expect_close;
80 static struct pci_dev *alim7101_pmu;
81
82 static int nowayout = WATCHDOG_NOWAYOUT;
83 module_param(nowayout, int, 0);
84 MODULE_PARM_DESC(nowayout,
85 "Watchdog cannot be stopped once started (default="
86 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
87
88 /*
89 * Whack the dog
90 */
91
92 static void wdt_timer_ping(unsigned long data)
93 {
94 /* If we got a heartbeat pulse within the WDT_US_INTERVAL
95 * we agree to ping the WDT
96 */
97 char tmp;
98
99 if (time_before(jiffies, next_heartbeat)) {
100 /* Ping the WDT (this is actually a disarm/arm sequence) */
101 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
102 pci_write_config_byte(alim7101_pmu,
103 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
104 pci_write_config_byte(alim7101_pmu,
105 ALI_7101_WDT, (tmp | ALI_WDT_ARM));
106 if (use_gpio) {
107 pci_read_config_byte(alim7101_pmu,
108 ALI_7101_GPIO_O, &tmp);
109 pci_write_config_byte(alim7101_pmu,
110 ALI_7101_GPIO_O, tmp | 0x20);
111 pci_write_config_byte(alim7101_pmu,
112 ALI_7101_GPIO_O, tmp & ~0x20);
113 }
114 } else {
115 printk(KERN_WARNING PFX
116 "Heartbeat lost! Will not ping the watchdog\n");
117 }
118 /* Re-set the timer interval */
119 mod_timer(&timer, jiffies + WDT_INTERVAL);
120 }
121
122 /*
123 * Utility routines
124 */
125
126 static void wdt_change(int writeval)
127 {
128 char tmp;
129
130 pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
131 if (writeval == WDT_ENABLE) {
132 pci_write_config_byte(alim7101_pmu,
133 ALI_7101_WDT, (tmp | ALI_WDT_ARM));
134 if (use_gpio) {
135 pci_read_config_byte(alim7101_pmu,
136 ALI_7101_GPIO_O, &tmp);
137 pci_write_config_byte(alim7101_pmu,
138 ALI_7101_GPIO_O, tmp & ~0x20);
139 }
140
141 } else {
142 pci_write_config_byte(alim7101_pmu,
143 ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
144 if (use_gpio) {
145 pci_read_config_byte(alim7101_pmu,
146 ALI_7101_GPIO_O, &tmp);
147 pci_write_config_byte(alim7101_pmu,
148 ALI_7101_GPIO_O, tmp | 0x20);
149 }
150 }
151 }
152
153 static void wdt_startup(void)
154 {
155 next_heartbeat = jiffies + (timeout * HZ);
156
157 /* We must enable before we kick off the timer in case the timer
158 occurs as we ping it */
159
160 wdt_change(WDT_ENABLE);
161
162 /* Start the timer */
163 mod_timer(&timer, jiffies + WDT_INTERVAL);
164
165 printk(KERN_INFO PFX "Watchdog timer is now enabled.\n");
166 }
167
168 static void wdt_turnoff(void)
169 {
170 /* Stop the timer */
171 del_timer_sync(&timer);
172 wdt_change(WDT_DISABLE);
173 printk(KERN_INFO PFX "Watchdog timer is now disabled...\n");
174 }
175
176 static void wdt_keepalive(void)
177 {
178 /* user land ping */
179 next_heartbeat = jiffies + (timeout * HZ);
180 }
181
182 /*
183 * /dev/watchdog handling
184 */
185
186 static ssize_t fop_write(struct file *file, const char __user *buf,
187 size_t count, loff_t *ppos)
188 {
189 /* See if we got the magic character 'V' and reload the timer */
190 if (count) {
191 if (!nowayout) {
192 size_t ofs;
193
194 /* note: just in case someone wrote the magic character
195 * five months ago... */
196 wdt_expect_close = 0;
197
198 /* now scan */
199 for (ofs = 0; ofs != count; ofs++) {
200 char c;
201 if (get_user(c, buf + ofs))
202 return -EFAULT;
203 if (c == 'V')
204 wdt_expect_close = 42;
205 }
206 }
207 /* someone wrote to us, we should restart timer */
208 wdt_keepalive();
209 }
210 return count;
211 }
212
213 static int fop_open(struct inode *inode, struct file *file)
214 {
215 /* Just in case we're already talking to someone... */
216 if (test_and_set_bit(0, &wdt_is_open))
217 return -EBUSY;
218 /* Good, fire up the show */
219 wdt_startup();
220 return nonseekable_open(inode, file);
221 }
222
223 static int fop_close(struct inode *inode, struct file *file)
224 {
225 if (wdt_expect_close == 42)
226 wdt_turnoff();
227 else {
228 /* wim: shouldn't there be a: del_timer(&timer); */
229 printk(KERN_CRIT PFX
230 "device file closed unexpectedly. Will not stop the WDT!\n");
231 }
232 clear_bit(0, &wdt_is_open);
233 wdt_expect_close = 0;
234 return 0;
235 }
236
237 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
238 {
239 void __user *argp = (void __user *)arg;
240 int __user *p = argp;
241 static struct watchdog_info ident = {
242 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
243 | WDIOF_MAGICCLOSE,
244 .firmware_version = 1,
245 .identity = "ALiM7101",
246 };
247
248 switch (cmd) {
249 case WDIOC_GETSUPPORT:
250 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
251 case WDIOC_GETSTATUS:
252 case WDIOC_GETBOOTSTATUS:
253 return put_user(0, p);
254 case WDIOC_SETOPTIONS:
255 {
256 int new_options, retval = -EINVAL;
257
258 if (get_user(new_options, p))
259 return -EFAULT;
260 if (new_options & WDIOS_DISABLECARD) {
261 wdt_turnoff();
262 retval = 0;
263 }
264 if (new_options & WDIOS_ENABLECARD) {
265 wdt_startup();
266 retval = 0;
267 }
268 return retval;
269 }
270 case WDIOC_KEEPALIVE:
271 wdt_keepalive();
272 return 0;
273 case WDIOC_SETTIMEOUT:
274 {
275 int new_timeout;
276
277 if (get_user(new_timeout, p))
278 return -EFAULT;
279 /* arbitrary upper limit */
280 if (new_timeout < 1 || new_timeout > 3600)
281 return -EINVAL;
282 timeout = new_timeout;
283 wdt_keepalive();
284 /* Fall through */
285 }
286 case WDIOC_GETTIMEOUT:
287 return put_user(timeout, p);
288 default:
289 return -ENOTTY;
290 }
291 }
292
293 static const struct file_operations wdt_fops = {
294 .owner = THIS_MODULE,
295 .llseek = no_llseek,
296 .write = fop_write,
297 .open = fop_open,
298 .release = fop_close,
299 .unlocked_ioctl = fop_ioctl,
300 };
301
302 static struct miscdevice wdt_miscdev = {
303 .minor = WATCHDOG_MINOR,
304 .name = "watchdog",
305 .fops = &wdt_fops,
306 };
307
308 /*
309 * Notifier for system down
310 */
311
312 static int wdt_notify_sys(struct notifier_block *this,
313 unsigned long code, void *unused)
314 {
315 if (code == SYS_DOWN || code == SYS_HALT)
316 wdt_turnoff();
317
318 if (code == SYS_RESTART) {
319 /*
320 * Cobalt devices have no way of rebooting themselves other
321 * than getting the watchdog to pull reset, so we restart the
322 * watchdog on reboot with no heartbeat
323 */
324 wdt_change(WDT_ENABLE);
325 printk(KERN_INFO PFX "Watchdog timer is now enabled "
326 "with no heartbeat - should reboot in ~1 second.\n");
327 }
328 return NOTIFY_DONE;
329 }
330
331 /*
332 * The WDT needs to learn about soft shutdowns in order to
333 * turn the timebomb registers off.
334 */
335
336 static struct notifier_block wdt_notifier = {
337 .notifier_call = wdt_notify_sys,
338 };
339
340 static void __exit alim7101_wdt_unload(void)
341 {
342 wdt_turnoff();
343 /* Deregister */
344 misc_deregister(&wdt_miscdev);
345 unregister_reboot_notifier(&wdt_notifier);
346 pci_dev_put(alim7101_pmu);
347 }
348
349 static int __init alim7101_wdt_init(void)
350 {
351 int rc = -EBUSY;
352 struct pci_dev *ali1543_south;
353 char tmp;
354
355 printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
356 alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
357 NULL);
358 if (!alim7101_pmu) {
359 printk(KERN_INFO PFX
360 "ALi M7101 PMU not present - WDT not set\n");
361 return -EBUSY;
362 }
363
364 /* Set the WDT in the PMU to 1 second */
365 pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
366
367 ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
368 NULL);
369 if (!ali1543_south) {
370 printk(KERN_INFO PFX
371 "ALi 1543 South-Bridge not present - WDT not set\n");
372 goto err_out;
373 }
374 pci_read_config_byte(ali1543_south, 0x5e, &tmp);
375 pci_dev_put(ali1543_south);
376 if ((tmp & 0x1e) == 0x00) {
377 if (!use_gpio) {
378 printk(KERN_INFO PFX
379 "Detected old alim7101 revision 'a1d'. "
380 "If this is a cobalt board, set the 'use_gpio' "
381 "module parameter.\n");
382 goto err_out;
383 }
384 nowayout = 1;
385 } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
386 printk(KERN_INFO PFX
387 "ALi 1543 South-Bridge does not have the correct "
388 "revision number (???1001?) - WDT not set\n");
389 goto err_out;
390 }
391
392 if (timeout < 1 || timeout > 3600) {
393 /* arbitrary upper limit */
394 timeout = WATCHDOG_TIMEOUT;
395 printk(KERN_INFO PFX
396 "timeout value must be 1 <= x <= 3600, using %d\n",
397 timeout);
398 }
399
400 rc = register_reboot_notifier(&wdt_notifier);
401 if (rc) {
402 printk(KERN_ERR PFX
403 "cannot register reboot notifier (err=%d)\n", rc);
404 goto err_out;
405 }
406
407 rc = misc_register(&wdt_miscdev);
408 if (rc) {
409 printk(KERN_ERR PFX
410 "cannot register miscdev on minor=%d (err=%d)\n",
411 wdt_miscdev.minor, rc);
412 goto err_out_reboot;
413 }
414
415 if (nowayout)
416 __module_get(THIS_MODULE);
417
418 printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. "
419 "timeout=%d sec (nowayout=%d)\n",
420 timeout, nowayout);
421 return 0;
422
423 err_out_reboot:
424 unregister_reboot_notifier(&wdt_notifier);
425 err_out:
426 pci_dev_put(alim7101_pmu);
427 return rc;
428 }
429
430 module_init(alim7101_wdt_init);
431 module_exit(alim7101_wdt_unload);
432
433 static struct pci_device_id alim7101_pci_tbl[] __devinitdata = {
434 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
435 { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
436 { }
437 };
438
439 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
440
441 MODULE_AUTHOR("Steve Hill");
442 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
443 MODULE_LICENSE("GPL");
444 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
445
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