[WATCHDOG] more coding style clean-up's
[linux-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 #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 with no heartbeat - should reboot in ~1 second.\n");
326         }
327         return NOTIFY_DONE;
328 }
329
330 /*
331  *      The WDT needs to learn about soft shutdowns in order to
332  *      turn the timebomb registers off.
333  */
334
335 static struct notifier_block wdt_notifier = {
336         .notifier_call = wdt_notify_sys,
337 };
338
339 static void __exit alim7101_wdt_unload(void)
340 {
341         wdt_turnoff();
342         /* Deregister */
343         misc_deregister(&wdt_miscdev);
344         unregister_reboot_notifier(&wdt_notifier);
345         pci_dev_put(alim7101_pmu);
346 }
347
348 static int __init alim7101_wdt_init(void)
349 {
350         int rc = -EBUSY;
351         struct pci_dev *ali1543_south;
352         char tmp;
353
354         printk(KERN_INFO PFX "Steve Hill <steve@navaho.co.uk>.\n");
355         alim7101_pmu = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101,
356                 NULL);
357         if (!alim7101_pmu) {
358                 printk(KERN_INFO PFX "ALi M7101 PMU not present - WDT not set\n");
359                 return -EBUSY;
360         }
361
362         /* Set the WDT in the PMU to 1 second */
363         pci_write_config_byte(alim7101_pmu, ALI_7101_WDT, 0x02);
364
365         ali1543_south = pci_get_device(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533,
366                 NULL);
367         if (!ali1543_south) {
368                 printk(KERN_INFO PFX
369                         "ALi 1543 South-Bridge not present - WDT not set\n");
370                 goto err_out;
371         }
372         pci_read_config_byte(ali1543_south, 0x5e, &tmp);
373         pci_dev_put(ali1543_south);
374         if ((tmp & 0x1e) == 0x00) {
375                 if (!use_gpio) {
376                         printk(KERN_INFO PFX "Detected old alim7101 revision 'a1d'.  If this is a cobalt board, set the 'use_gpio' module parameter.\n");
377                         goto err_out;
378                 }
379                 nowayout = 1;
380         } else if ((tmp & 0x1e) != 0x12 && (tmp & 0x1e) != 0x00) {
381                 printk(KERN_INFO PFX "ALi 1543 South-Bridge does not have the correct revision number (???1001?) - WDT not set\n");
382                 goto err_out;
383         }
384
385         if (timeout < 1 || timeout > 3600) {
386                 /* arbitrary upper limit */
387                 timeout = WATCHDOG_TIMEOUT;
388                 printk(KERN_INFO PFX
389                         "timeout value must be 1 <= x <= 3600, using %d\n",
390                                                                 timeout);
391         }
392
393         rc = register_reboot_notifier(&wdt_notifier);
394         if (rc) {
395                 printk(KERN_ERR PFX
396                         "cannot register reboot notifier (err=%d)\n", rc);
397                 goto err_out;
398         }
399
400         rc = misc_register(&wdt_miscdev);
401         if (rc) {
402                 printk(KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
403                         wdt_miscdev.minor, rc);
404                 goto err_out_reboot;
405         }
406
407         if (nowayout)
408                 __module_get(THIS_MODULE);
409
410         printk(KERN_INFO PFX "WDT driver for ALi M7101 initialised. timeout=%d sec (nowayout=%d)\n",
411                 timeout, nowayout);
412         return 0;
413
414 err_out_reboot:
415         unregister_reboot_notifier(&wdt_notifier);
416 err_out:
417         pci_dev_put(alim7101_pmu);
418         return rc;
419 }
420
421 module_init(alim7101_wdt_init);
422 module_exit(alim7101_wdt_unload);
423
424 static struct pci_device_id alim7101_pci_tbl[] __devinitdata = {
425         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M1533) },
426         { PCI_DEVICE(PCI_VENDOR_ID_AL, PCI_DEVICE_ID_AL_M7101) },
427         { }
428 };
429
430 MODULE_DEVICE_TABLE(pci, alim7101_pci_tbl);
431
432 MODULE_AUTHOR("Steve Hill");
433 MODULE_DESCRIPTION("ALi M7101 PMU Computer Watchdog Timer driver");
434 MODULE_LICENSE("GPL");
435 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);