watchdog: Use pr_<fmt> and pr_<level>
[sfrench/cifs-2.6.git] / drivers / watchdog / alim7101_wdt.c
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 #include <asm/system.h>
40
41 #define WDT_ENABLE 0x9C
42 #define WDT_DISABLE 0x8C
43
44 #define ALI_7101_WDT    0x92
45 #define ALI_7101_GPIO   0x7D
46 #define ALI_7101_GPIO_O 0x7E
47 #define ALI_WDT_ARM     0x01
48
49 /*
50  * We're going to use a 1 second timeout.
51  * If we reset the watchdog every ~250ms we should be safe.  */
52
53 #define WDT_INTERVAL (HZ/4+1)
54
55 /*
56  * We must not require too good response from the userspace daemon.
57  * Here we require the userspace daemon to send us a heartbeat
58  * char to /dev/watchdog every 30 seconds.
59  */
60
61 #define WATCHDOG_TIMEOUT 30            /* 30 sec default timeout */
62 /* in seconds, will be multiplied by HZ to get seconds to wait for a ping */
63 static int timeout = WATCHDOG_TIMEOUT;
64 module_param(timeout, int, 0);
65 MODULE_PARM_DESC(timeout,
66                 "Watchdog timeout in seconds. (1<=timeout<=3600, default="
67                                 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
68
69 static int use_gpio; /* Use the pic (for a1d revision alim7101) */
70 module_param(use_gpio, int, 0);
71 MODULE_PARM_DESC(use_gpio,
72                 "Use the gpio watchdog (required by old cobalt boards).");
73
74 static void wdt_timer_ping(unsigned long);
75 static DEFINE_TIMER(timer, wdt_timer_ping, 0, 1);
76 static unsigned long next_heartbeat;
77 static unsigned long wdt_is_open;
78 static char wdt_expect_close;
79 static struct pci_dev *alim7101_pmu;
80
81 static int nowayout = WATCHDOG_NOWAYOUT;
82 module_param(nowayout, int, 0);
83 MODULE_PARM_DESC(nowayout,
84                 "Watchdog cannot be stopped once started (default="
85                                 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
86
87 /*
88  *      Whack the dog
89  */
90
91 static void wdt_timer_ping(unsigned long data)
92 {
93         /* If we got a heartbeat pulse within the WDT_US_INTERVAL
94          * we agree to ping the WDT
95          */
96         char tmp;
97
98         if (time_before(jiffies, next_heartbeat)) {
99                 /* Ping the WDT (this is actually a disarm/arm sequence) */
100                 pci_read_config_byte(alim7101_pmu, 0x92, &tmp);
101                 pci_write_config_byte(alim7101_pmu,
102                                         ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
103                 pci_write_config_byte(alim7101_pmu,
104                                         ALI_7101_WDT, (tmp | ALI_WDT_ARM));
105                 if (use_gpio) {
106                         pci_read_config_byte(alim7101_pmu,
107                                         ALI_7101_GPIO_O, &tmp);
108                         pci_write_config_byte(alim7101_pmu,
109                                         ALI_7101_GPIO_O, tmp | 0x20);
110                         pci_write_config_byte(alim7101_pmu,
111                                         ALI_7101_GPIO_O, tmp & ~0x20);
112                 }
113         } else {
114                 pr_warn("Heartbeat lost! Will not ping the watchdog\n");
115         }
116         /* Re-set the timer interval */
117         mod_timer(&timer, jiffies + WDT_INTERVAL);
118 }
119
120 /*
121  * Utility routines
122  */
123
124 static void wdt_change(int writeval)
125 {
126         char tmp;
127
128         pci_read_config_byte(alim7101_pmu, ALI_7101_WDT, &tmp);
129         if (writeval == WDT_ENABLE) {
130                 pci_write_config_byte(alim7101_pmu,
131                                         ALI_7101_WDT, (tmp | ALI_WDT_ARM));
132                 if (use_gpio) {
133                         pci_read_config_byte(alim7101_pmu,
134                                         ALI_7101_GPIO_O, &tmp);
135                         pci_write_config_byte(alim7101_pmu,
136                                         ALI_7101_GPIO_O, tmp & ~0x20);
137                 }
138
139         } else {
140                 pci_write_config_byte(alim7101_pmu,
141                                         ALI_7101_WDT, (tmp & ~ALI_WDT_ARM));
142                 if (use_gpio) {
143                         pci_read_config_byte(alim7101_pmu,
144                                         ALI_7101_GPIO_O, &tmp);
145                         pci_write_config_byte(alim7101_pmu,
146                                         ALI_7101_GPIO_O, tmp | 0x20);
147                 }
148         }
149 }
150
151 static void wdt_startup(void)
152 {
153         next_heartbeat = jiffies + (timeout * HZ);
154
155         /* We must enable before we kick off the timer in case the timer
156            occurs as we ping it */
157
158         wdt_change(WDT_ENABLE);
159
160         /* Start the timer */
161         mod_timer(&timer, jiffies + WDT_INTERVAL);
162
163         pr_info("Watchdog timer is now enabled\n");
164 }
165
166 static void wdt_turnoff(void)
167 {
168         /* Stop the timer */
169         del_timer_sync(&timer);
170         wdt_change(WDT_DISABLE);
171         pr_info("Watchdog timer is now disabled...\n");
172 }
173
174 static void wdt_keepalive(void)
175 {
176         /* user land ping */
177         next_heartbeat = jiffies + (timeout * HZ);
178 }
179
180 /*
181  * /dev/watchdog handling
182  */
183
184 static ssize_t fop_write(struct file *file, const char __user *buf,
185                                                 size_t count, loff_t *ppos)
186 {
187         /* See if we got the magic character 'V' and reload the timer */
188         if (count) {
189                 if (!nowayout) {
190                         size_t ofs;
191
192                         /* note: just in case someone wrote the magic character
193                          * five months ago... */
194                         wdt_expect_close = 0;
195
196                         /* now scan */
197                         for (ofs = 0; ofs != count; ofs++) {
198                                 char c;
199                                 if (get_user(c, buf + ofs))
200                                         return -EFAULT;
201                                 if (c == 'V')
202                                         wdt_expect_close = 42;
203                         }
204                 }
205                 /* someone wrote to us, we should restart timer */
206                 wdt_keepalive();
207         }
208         return count;
209 }
210
211 static int fop_open(struct inode *inode, struct file *file)
212 {
213         /* Just in case we're already talking to someone... */
214         if (test_and_set_bit(0, &wdt_is_open))
215                 return -EBUSY;
216         /* Good, fire up the show */
217         wdt_startup();
218         return nonseekable_open(inode, file);
219 }
220
221 static int fop_close(struct inode *inode, struct file *file)
222 {
223         if (wdt_expect_close == 42)
224                 wdt_turnoff();
225         else {
226                 /* wim: shouldn't there be a: del_timer(&timer); */
227                 pr_crit("device file closed unexpectedly. Will not stop the WDT!\n");
228         }
229         clear_bit(0, &wdt_is_open);
230         wdt_expect_close = 0;
231         return 0;
232 }
233
234 static long fop_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
235 {
236         void __user *argp = (void __user *)arg;
237         int __user *p = argp;
238         static const struct watchdog_info ident = {
239                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT
240                                                         | WDIOF_MAGICCLOSE,
241                 .firmware_version = 1,
242                 .identity = "ALiM7101",
243         };
244
245         switch (cmd) {
246         case WDIOC_GETSUPPORT:
247                 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
248         case WDIOC_GETSTATUS:
249         case WDIOC_GETBOOTSTATUS:
250                 return put_user(0, p);
251         case WDIOC_SETOPTIONS:
252         {
253                 int new_options, retval = -EINVAL;
254
255                 if (get_user(new_options, p))
256                         return -EFAULT;
257                 if (new_options & WDIOS_DISABLECARD) {
258                         wdt_turnoff();
259                         retval = 0;
260                 }
261                 if (new_options & WDIOS_ENABLECARD) {
262                         wdt_startup();
263                         retval = 0;
264                 }
265                 return retval;
266         }
267         case WDIOC_KEEPALIVE:
268                 wdt_keepalive();
269                 return 0;
270         case WDIOC_SETTIMEOUT:
271         {
272                 int new_timeout;
273
274                 if (get_user(new_timeout, p))
275                         return -EFAULT;
276                 /* arbitrary upper limit */
277                 if (new_timeout < 1 || new_timeout > 3600)
278                         return -EINVAL;
279                 timeout = new_timeout;
280                 wdt_keepalive();
281                 /* Fall through */
282         }
283         case WDIOC_GETTIMEOUT:
284                 return put_user(timeout, p);
285         default:
286                 return -ENOTTY;
287         }
288 }
289
290 static const struct file_operations wdt_fops = {
291         .owner          =       THIS_MODULE,
292         .llseek         =       no_llseek,
293         .write          =       fop_write,
294         .open           =       fop_open,
295         .release        =       fop_close,
296         .unlocked_ioctl =       fop_ioctl,
297 };
298
299 static struct miscdevice wdt_miscdev = {
300         .minor  =       WATCHDOG_MINOR,
301         .name   =       "watchdog",
302         .fops   =       &wdt_fops,
303 };
304
305 /*
306  *      Notifier for system down
307  */
308
309 static int wdt_notify_sys(struct notifier_block *this,
310                                         unsigned long code, void *unused)
311 {
312         if (code == SYS_DOWN || code == SYS_HALT)
313                 wdt_turnoff();
314
315         if (code == SYS_RESTART) {
316                 /*
317                  * Cobalt devices have no way of rebooting themselves other
318                  * than getting the watchdog to pull reset, so we restart the
319                  * watchdog on reboot with no heartbeat
320                  */
321                 wdt_change(WDT_ENABLE);
322                 pr_info("Watchdog timer is now enabled with no heartbeat - should reboot in ~1 second\n");
323         }
324         return NOTIFY_DONE;
325 }
326
327 /*
328  *      The WDT needs to learn about soft shutdowns in order to
329  *      turn the timebomb registers off.
330  */
331
332 static struct notifier_block wdt_notifier = {
333         .notifier_call = wdt_notify_sys,
334 };
335
336 static void __exit alim7101_wdt_unload(void)
337 {
338         wdt_turnoff();
339         /* Deregister */
340         misc_deregister(&wdt_miscdev);
341         unregister_reboot_notifier(&wdt_notifier);
342         pci_dev_put(alim7101_pmu);
343 }
344
345 static int __init alim7101_wdt_init(void)
346 {
347         int rc = -EBUSY;
348         struct pci_dev *ali1543_south;
349         char tmp;
350
351         pr_info("Steve Hill <steve@navaho.co.uk>\n");
352         alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
353                 NULL);
354         if (!alim7101_pmu) {
355                 pr_info("ALi M7101 PMU not present - WDT not set\n");
356                 return -EBUSY;
357         }
358
359         /* Set the WDT in the PMU to 1 second */
360         pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
361
362         ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
363                 NULL);
364         if (!ali1543_south) {
365                 pr_info("ALi 1543 South-Bridge not present - WDT not set\n");
366                 goto err_out;
367         }
368         pci_read_config_byte(ali1543_south, 0x5e, &tmp);
369         pci_dev_put(ali1543_south);
370         if ((tmp & 0x1e) == 0x00) {
371                 if (!use_gpio) {
372                         pr_info("Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
373                         goto err_out;
374                 }
375                 nowayout = 1;
376         } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
377                 pr_info("ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
378                 goto err_out;
379         }
380
381         if (timeout < 1 || timeout > 3600) {
382                 /* arbitrary upper limit */
383                 timeout = WATCHDOG_TIMEOUT;
384                 pr_info("timeout value must be 1 <= x <= 3600, using %d\n",
385                         timeout);
386         }
387
388         rc = register_reboot_notifier(&wdt_notifier);
389         if (rc) {
390                 pr_err("cannot register reboot notifier (err=%d)\n", rc);
391                 goto err_out;
392         }
393
394         rc = misc_register(&wdt_miscdev);
395         if (rc) {
396                 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
397                        wdt_miscdev.minor, rc);
398                 goto err_out_reboot;
399         }
400
401         if (nowayout)
402                 __module_get(THIS_MODULE);
403
404         pr_info("WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
405                 timeout, nowayout);
406         return 0;
407
408 err_out_reboot:
409         unregister_reboot_notifier(&wdt_notifier);
410 err_out:
411         pci_dev_put(alim7101_pmu);
412         return rc;
413 }
414
415 module_init(alim7101_wdt_init);
416 module_exit(alim7101_wdt_unload);
417
418 static DEFINE_PCI_DEVICE_TABLE(alim7101_pci_tbl) __used = {
419         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
420         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
421         { }
422 };
423
424 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
425
426 MODULE_AUTHOR("Steve Hill");
427 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
428 MODULE_LICENSE("GPL");
429 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);