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