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