[PATCH] make more file_operation structs static
[linux-2.6] / 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=CONFIG_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 int zf_action = GEN_RESET;
122 static unsigned long zf_is_open;
123 static char zf_expect_close;
124 static spinlock_t zf_lock;
125 static spinlock_t zf_port_lock;
126 static struct timer_list zf_timer;
127 static unsigned long next_heartbeat = 0;
128
129
130 /* timeout for user land heart beat (10 seconds) */
131 #define ZF_USER_TIMEO (HZ*10)
132
133 /* timeout for hardware watchdog (~500ms) */
134 #define ZF_HW_TIMEO (HZ/2)
135
136 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
137 #define ZF_CTIMEOUT 0xffff
138
139 #ifndef ZF_DEBUG
140 #       define dprintk(format, args...)
141 #else
142 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
143 #endif
144
145
146 static inline void zf_set_status(unsigned char new)
147 {
148         zf_writeb(STATUS, new);
149 }
150
151
152 /* CONTROL register functions */
153
154 static inline unsigned short zf_get_control(void)
155 {
156         return zf_readw(CONTROL);
157 }
158
159 static inline void zf_set_control(unsigned short new)
160 {
161         zf_writew(CONTROL, new);
162 }
163
164
165 /* WD#? counter functions */
166 /*
167  *      Just set counter value
168  */
169
170 static inline void zf_set_timer(unsigned short new, unsigned char n)
171 {
172         switch(n){
173                 case WD1:
174                         zf_writew(COUNTER_1, new);
175                 case WD2:
176                         zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
177                 default:
178                         return;
179         }
180 }
181
182 /*
183  * stop hardware timer
184  */
185 static void zf_timer_off(void)
186 {
187         unsigned int ctrl_reg = 0;
188         unsigned long flags;
189
190         /* stop internal ping */
191         del_timer_sync(&zf_timer);
192
193         spin_lock_irqsave(&zf_port_lock, flags);
194         /* stop watchdog timer */
195         ctrl_reg = zf_get_control();
196         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
197         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
198         zf_set_control(ctrl_reg);
199         spin_unlock_irqrestore(&zf_port_lock, flags);
200
201         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
202 }
203
204
205 /*
206  * start hardware timer
207  */
208 static void zf_timer_on(void)
209 {
210         unsigned int ctrl_reg = 0;
211         unsigned long flags;
212
213         spin_lock_irqsave(&zf_port_lock, flags);
214
215         zf_writeb(PULSE_LEN, 0xff);
216
217         zf_set_timer(ZF_CTIMEOUT, WD1);
218
219         /* user land ping */
220         next_heartbeat = jiffies + ZF_USER_TIMEO;
221
222         /* start the timer for internal ping */
223         zf_timer.expires = jiffies + ZF_HW_TIMEO;
224
225         add_timer(&zf_timer);
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                 zf_timer.expires = jiffies + ZF_HW_TIMEO;
264                 add_timer(&zf_timer);
265         }else{
266                 printk(KERN_CRIT PFX ": I will reset your machine\n");
267         }
268 }
269
270 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
271                                                                 loff_t *ppos)
272 {
273         /* See if we got the magic character */
274         if(count){
275
276                 /*
277                  * no need to check for close confirmation
278                  * no way to disable watchdog ;)
279                  */
280                 if (!nowayout) {
281                         size_t ofs;
282
283                         /*
284                          * note: just in case someone wrote the magic character
285                          * five months ago...
286                          */
287                         zf_expect_close = 0;
288
289                         /* now scan */
290                         for (ofs = 0; ofs != count; ofs++){
291                                 char c;
292                                 if (get_user(c, buf + ofs))
293                                         return -EFAULT;
294                                 if (c == 'V'){
295                                         zf_expect_close = 42;
296                                         dprintk("zf_expect_close = 42\n");
297                                 }
298                         }
299                 }
300
301                 /*
302                  * Well, anyhow someone wrote to us,
303                  * we should return that favour
304                  */
305                 next_heartbeat = jiffies + ZF_USER_TIMEO;
306                 dprintk("user ping at %ld\n", jiffies);
307
308         }
309
310         return count;
311 }
312
313 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
314         unsigned long arg)
315 {
316         void __user *argp = (void __user *)arg;
317         int __user *p = argp;
318         switch(cmd){
319                 case WDIOC_GETSUPPORT:
320                         if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
321                                 return -EFAULT;
322                         break;
323
324                 case WDIOC_GETSTATUS:
325                         return put_user(0, p);
326
327                 case WDIOC_KEEPALIVE:
328                         zf_ping(0);
329                         break;
330
331                 default:
332                         return -ENOIOCTLCMD;
333         }
334
335         return 0;
336 }
337
338 static int zf_open(struct inode *inode, struct file *file)
339 {
340         spin_lock(&zf_lock);
341         if(test_and_set_bit(0, &zf_is_open)) {
342                 spin_unlock(&zf_lock);
343                 return -EBUSY;
344         }
345
346         if (nowayout)
347                 __module_get(THIS_MODULE);
348
349         spin_unlock(&zf_lock);
350
351         zf_timer_on();
352
353         return nonseekable_open(inode, file);
354 }
355
356 static int zf_close(struct inode *inode, struct file *file)
357 {
358         if(zf_expect_close == 42){
359                 zf_timer_off();
360         } else {
361                 del_timer(&zf_timer);
362                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
363         }
364
365         spin_lock(&zf_lock);
366         clear_bit(0, &zf_is_open);
367         spin_unlock(&zf_lock);
368
369         zf_expect_close = 0;
370
371         return 0;
372 }
373
374 /*
375  * Notifier for system down
376  */
377
378 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
379                                                                 void *unused)
380 {
381         if(code == SYS_DOWN || code == SYS_HALT){
382                 zf_timer_off();
383         }
384
385         return NOTIFY_DONE;
386 }
387
388
389
390
391 static const struct file_operations zf_fops = {
392         .owner          = THIS_MODULE,
393         .llseek         = no_llseek,
394         .write          = zf_write,
395         .ioctl          = zf_ioctl,
396         .open           = zf_open,
397         .release        = zf_close,
398 };
399
400 static struct miscdevice zf_miscdev = {
401         .minor = WATCHDOG_MINOR,
402         .name = "watchdog",
403         .fops = &zf_fops,
404 };
405  
406
407 /*
408  * The device needs to learn about soft shutdowns in order to
409  * turn the timebomb registers off.
410  */
411 static struct notifier_block zf_notifier = {
412         .notifier_call = zf_notify_sys,
413 };
414
415 static void __init zf_show_action(int act)
416 {
417         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
418
419         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
420 }
421
422 static int __init zf_init(void)
423 {
424         int ret;
425
426         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
427
428         ret = zf_get_ZFL_version();
429         printk("%#x\n", ret);
430         if((!ret) || (ret != 0xffff)){
431                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
432                 return -ENODEV;
433         }
434
435         if((action <= 3) && (action >= 0)){
436                 zf_action = zf_action>>action;
437         } else
438                 action = 0;
439
440         zf_show_action(action);
441
442         spin_lock_init(&zf_lock);
443         spin_lock_init(&zf_port_lock);
444
445         ret = misc_register(&zf_miscdev);
446         if (ret){
447                 printk(KERN_ERR "can't misc_register on minor=%d\n",
448                                                         WATCHDOG_MINOR);
449                 goto out;
450         }
451
452         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
453                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
454                                                         ZF_IOBASE);
455                 ret = -EBUSY;
456                 goto no_region;
457         }
458
459         ret = register_reboot_notifier(&zf_notifier);
460         if(ret){
461                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
462                                                                         ret);
463                 goto no_reboot;
464         }
465
466         zf_set_status(0);
467         zf_set_control(0);
468
469         /* this is the timer that will do the hard work */
470         init_timer(&zf_timer);
471         zf_timer.function = zf_ping;
472         zf_timer.data = 0;
473
474         return 0;
475
476 no_reboot:
477         release_region(ZF_IOBASE, 3);
478 no_region:
479         misc_deregister(&zf_miscdev);
480 out:
481         return ret;
482 }
483
484
485 static void __exit zf_exit(void)
486 {
487         zf_timer_off();
488
489         misc_deregister(&zf_miscdev);
490         unregister_reboot_notifier(&zf_notifier);
491         release_region(ZF_IOBASE, 3);
492 }
493
494 module_init(zf_init);
495 module_exit(zf_exit);