Merge master.kernel.org:/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
[linux-2.6.git] / drivers / char / watchdog / machzwd.c
1 /*
2  *  MachZ ZF-Logic Watchdog Timer driver for Linux
3  *
4  *
5  *  This program is free software; you can redistribute it and/or
6  *  modify it under the terms of the GNU General Public License
7  *  as published by the Free Software Foundation; either version
8  *  2 of the License, or (at your option) any later version.
9  *
10  *  The author does NOT admit liability nor provide warranty for
11  *  any of this software. This material is provided "AS-IS" in
12  *  the hope that it may be useful for others.
13  *
14  *  Author: Fernando Fuganti <fuganti@conectiva.com.br>
15  *
16  *  Based on sbc60xxwdt.c by Jakob Oestergaard
17  *
18  *
19  *  We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
20  *  following periods:
21  *      wd#1 - 2 seconds;
22  *      wd#2 - 7.2 ms;
23  *  After the expiration of wd#1, it can generate a NMI, SCI, SMI, or
24  *  a system RESET and it starts wd#2 that unconditionaly will RESET
25  *  the system when the counter reaches zero.
26  *
27  *  14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
28  *      Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
29  */
30
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/types.h>
34 #include <linux/timer.h>
35 #include <linux/jiffies.h>
36 #include <linux/miscdevice.h>
37 #include <linux/watchdog.h>
38 #include <linux/fs.h>
39 #include <linux/ioport.h>
40 #include <linux/notifier.h>
41 #include <linux/reboot.h>
42 #include <linux/init.h>
43
44 #include <asm/io.h>
45 #include <asm/uaccess.h>
46 #include <asm/system.h>
47
48 /* ports */
49 #define ZF_IOBASE       0x218
50 #define INDEX           0x218
51 #define DATA_B          0x219
52 #define DATA_W          0x21A
53 #define DATA_D          0x21A
54
55 /* indexes */                   /* size */
56 #define ZFL_VERSION     0x02    /* 16   */
57 #define CONTROL         0x10    /* 16   */
58 #define STATUS          0x12    /* 8    */
59 #define COUNTER_1       0x0C    /* 16   */
60 #define COUNTER_2       0x0E    /* 8    */
61 #define PULSE_LEN       0x0F    /* 8    */
62
63 /* controls */
64 #define ENABLE_WD1      0x0001
65 #define ENABLE_WD2      0x0002
66 #define RESET_WD1       0x0010
67 #define RESET_WD2       0x0020
68 #define GEN_SCI         0x0100
69 #define GEN_NMI         0x0200
70 #define GEN_SMI         0x0400
71 #define GEN_RESET       0x0800
72
73
74 /* utilities */
75
76 #define WD1     0
77 #define WD2     1
78
79 #define zf_writew(port, data)  { outb(port, INDEX); outw(data, DATA_W); }
80 #define zf_writeb(port, data)  { outb(port, INDEX); outb(data, DATA_B); }
81 #define zf_get_ZFL_version()   zf_readw(ZFL_VERSION)
82
83
84 static unsigned short zf_readw(unsigned char port)
85 {
86         outb(port, INDEX);
87         return inw(DATA_W);
88 }
89
90
91 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
92 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
93 MODULE_LICENSE("GPL");
94 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
95
96 static int nowayout = WATCHDOG_NOWAYOUT;
97 module_param(nowayout, int, 0);
98 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
99
100 #define PFX "machzwd"
101
102 static struct watchdog_info zf_info = {
103         .options                = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
104         .firmware_version       = 1,
105         .identity               = "ZF-Logic watchdog",
106 };
107
108
109 /*
110  * action refers to action taken when watchdog resets
111  * 0 = GEN_RESET
112  * 1 = GEN_SMI
113  * 2 = GEN_NMI
114  * 3 = GEN_SCI
115  * defaults to GEN_RESET (0)
116  */
117 static int action = 0;
118 module_param(action, int, 0);
119 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
120
121 static void zf_ping(unsigned long data);
122
123 static int zf_action = GEN_RESET;
124 static unsigned long zf_is_open;
125 static char zf_expect_close;
126 static spinlock_t zf_lock;
127 static spinlock_t zf_port_lock;
128 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
129 static unsigned long next_heartbeat = 0;
130
131
132 /* timeout for user land heart beat (10 seconds) */
133 #define ZF_USER_TIMEO (HZ*10)
134
135 /* timeout for hardware watchdog (~500ms) */
136 #define ZF_HW_TIMEO (HZ/2)
137
138 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
139 #define ZF_CTIMEOUT 0xffff
140
141 #ifndef ZF_DEBUG
142 #       define dprintk(format, args...)
143 #else
144 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
145 #endif
146
147
148 static inline void zf_set_status(unsigned char new)
149 {
150         zf_writeb(STATUS, new);
151 }
152
153
154 /* CONTROL register functions */
155
156 static inline unsigned short zf_get_control(void)
157 {
158         return zf_readw(CONTROL);
159 }
160
161 static inline void zf_set_control(unsigned short new)
162 {
163         zf_writew(CONTROL, new);
164 }
165
166
167 /* WD#? counter functions */
168 /*
169  *      Just set counter value
170  */
171
172 static inline void zf_set_timer(unsigned short new, unsigned char n)
173 {
174         switch(n){
175                 case WD1:
176                         zf_writew(COUNTER_1, new);
177                 case WD2:
178                         zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
179                 default:
180                         return;
181         }
182 }
183
184 /*
185  * stop hardware timer
186  */
187 static void zf_timer_off(void)
188 {
189         unsigned int ctrl_reg = 0;
190         unsigned long flags;
191
192         /* stop internal ping */
193         del_timer_sync(&zf_timer);
194
195         spin_lock_irqsave(&zf_port_lock, flags);
196         /* stop watchdog timer */
197         ctrl_reg = zf_get_control();
198         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
199         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
200         zf_set_control(ctrl_reg);
201         spin_unlock_irqrestore(&zf_port_lock, flags);
202
203         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
204 }
205
206
207 /*
208  * start hardware timer
209  */
210 static void zf_timer_on(void)
211 {
212         unsigned int ctrl_reg = 0;
213         unsigned long flags;
214
215         spin_lock_irqsave(&zf_port_lock, flags);
216
217         zf_writeb(PULSE_LEN, 0xff);
218
219         zf_set_timer(ZF_CTIMEOUT, WD1);
220
221         /* user land ping */
222         next_heartbeat = jiffies + ZF_USER_TIMEO;
223
224         /* start the timer for internal ping */
225         mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
226
227         /* start watchdog timer */
228         ctrl_reg = zf_get_control();
229         ctrl_reg |= (ENABLE_WD1|zf_action);
230         zf_set_control(ctrl_reg);
231         spin_unlock_irqrestore(&zf_port_lock, flags);
232
233         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
234 }
235
236
237 static void zf_ping(unsigned long data)
238 {
239         unsigned int ctrl_reg = 0;
240         unsigned long flags;
241
242         zf_writeb(COUNTER_2, 0xff);
243
244         if(time_before(jiffies, next_heartbeat)){
245
246                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
247
248                 /*
249                  * reset event is activated by transition from 0 to 1 on
250                  * RESET_WD1 bit and we assume that it is already zero...
251                  */
252
253                 spin_lock_irqsave(&zf_port_lock, flags);
254                 ctrl_reg = zf_get_control();
255                 ctrl_reg |= RESET_WD1;
256                 zf_set_control(ctrl_reg);
257
258                 /* ...and nothing changes until here */
259                 ctrl_reg &= ~(RESET_WD1);
260                 zf_set_control(ctrl_reg);
261                 spin_unlock_irqrestore(&zf_port_lock, flags);
262
263                 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
264         }else{
265                 printk(KERN_CRIT PFX ": I will reset your machine\n");
266         }
267 }
268
269 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
270                                                                 loff_t *ppos)
271 {
272         /* See if we got the magic character */
273         if(count){
274
275                 /*
276                  * no need to check for close confirmation
277                  * no way to disable watchdog ;)
278                  */
279                 if (!nowayout) {
280                         size_t ofs;
281
282                         /*
283                          * note: just in case someone wrote the magic character
284                          * five months ago...
285                          */
286                         zf_expect_close = 0;
287
288                         /* now scan */
289                         for (ofs = 0; ofs != count; ofs++){
290                                 char c;
291                                 if (get_user(c, buf + ofs))
292                                         return -EFAULT;
293                                 if (c == 'V'){
294                                         zf_expect_close = 42;
295                                         dprintk("zf_expect_close = 42\n");
296                                 }
297                         }
298                 }
299
300                 /*
301                  * Well, anyhow someone wrote to us,
302                  * we should return that favour
303                  */
304                 next_heartbeat = jiffies + ZF_USER_TIMEO;
305                 dprintk("user ping at %ld\n", jiffies);
306
307         }
308
309         return count;
310 }
311
312 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
313         unsigned long arg)
314 {
315         void __user *argp = (void __user *)arg;
316         int __user *p = argp;
317         switch(cmd){
318                 case WDIOC_GETSUPPORT:
319                         if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
320                                 return -EFAULT;
321                         break;
322
323                 case WDIOC_GETSTATUS:
324                         return put_user(0, p);
325
326                 case WDIOC_KEEPALIVE:
327                         zf_ping(NULL);
328                         break;
329
330                 default:
331                         return -ENOTTY;
332         }
333
334         return 0;
335 }
336
337 static int zf_open(struct inode *inode, struct file *file)
338 {
339         spin_lock(&zf_lock);
340         if(test_and_set_bit(0, &zf_is_open)) {
341                 spin_unlock(&zf_lock);
342                 return -EBUSY;
343         }
344
345         if (nowayout)
346                 __module_get(THIS_MODULE);
347
348         spin_unlock(&zf_lock);
349
350         zf_timer_on();
351
352         return nonseekable_open(inode, file);
353 }
354
355 static int zf_close(struct inode *inode, struct file *file)
356 {
357         if(zf_expect_close == 42){
358                 zf_timer_off();
359         } else {
360                 del_timer(&zf_timer);
361                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
362         }
363
364         spin_lock(&zf_lock);
365         clear_bit(0, &zf_is_open);
366         spin_unlock(&zf_lock);
367
368         zf_expect_close = 0;
369
370         return 0;
371 }
372
373 /*
374  * Notifier for system down
375  */
376
377 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
378                                                                 void *unused)
379 {
380         if(code == SYS_DOWN || code == SYS_HALT){
381                 zf_timer_off();
382         }
383
384         return NOTIFY_DONE;
385 }
386
387
388
389
390 static const struct file_operations zf_fops = {
391         .owner          = THIS_MODULE,
392         .llseek         = no_llseek,
393         .write          = zf_write,
394         .ioctl          = zf_ioctl,
395         .open           = zf_open,
396         .release        = zf_close,
397 };
398
399 static struct miscdevice zf_miscdev = {
400         .minor = WATCHDOG_MINOR,
401         .name = "watchdog",
402         .fops = &zf_fops,
403 };
404  
405
406 /*
407  * The device needs to learn about soft shutdowns in order to
408  * turn the timebomb registers off.
409  */
410 static struct notifier_block zf_notifier = {
411         .notifier_call = zf_notify_sys,
412 };
413
414 static void __init zf_show_action(int act)
415 {
416         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
417
418         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
419 }
420
421 static int __init zf_init(void)
422 {
423         int ret;
424
425         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
426
427         ret = zf_get_ZFL_version();
428         if ((!ret) || (ret == 0xffff)) {
429                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
430                 return -ENODEV;
431         }
432
433         if((action <= 3) && (action >= 0)){
434                 zf_action = zf_action>>action;
435         } else
436                 action = 0;
437
438         zf_show_action(action);
439
440         spin_lock_init(&zf_lock);
441         spin_lock_init(&zf_port_lock);
442
443         ret = misc_register(&zf_miscdev);
444         if (ret){
445                 printk(KERN_ERR "can't misc_register on minor=%d\n",
446                                                         WATCHDOG_MINOR);
447                 goto out;
448         }
449
450         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
451                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
452                                                         ZF_IOBASE);
453                 ret = -EBUSY;
454                 goto no_region;
455         }
456
457         ret = register_reboot_notifier(&zf_notifier);
458         if(ret){
459                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
460                                                                         ret);
461                 goto no_reboot;
462         }
463
464         zf_set_status(0);
465         zf_set_control(0);
466
467         return 0;
468
469 no_reboot:
470         release_region(ZF_IOBASE, 3);
471 no_region:
472         misc_deregister(&zf_miscdev);
473 out:
474         return ret;
475 }
476
477
478 static void __exit zf_exit(void)
479 {
480         zf_timer_off();
481
482         misc_deregister(&zf_miscdev);
483         unregister_reboot_notifier(&zf_notifier);
484         release_region(ZF_IOBASE, 3);
485 }
486
487 module_init(zf_init);
488 module_exit(zf_exit);