[PATCH] Detaching fbcon: sdd sysfs class device entry for fbcon
[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/config.h>
32 #include <linux/module.h>
33 #include <linux/moduleparam.h>
34 #include <linux/types.h>
35 #include <linux/timer.h>
36 #include <linux/jiffies.h>
37 #include <linux/miscdevice.h>
38 #include <linux/watchdog.h>
39 #include <linux/fs.h>
40 #include <linux/ioport.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/init.h>
44
45 #include <asm/io.h>
46 #include <asm/uaccess.h>
47 #include <asm/system.h>
48
49 /* ports */
50 #define ZF_IOBASE       0x218
51 #define INDEX           0x218
52 #define DATA_B          0x219
53 #define DATA_W          0x21A
54 #define DATA_D          0x21A
55
56 /* indexes */                   /* size */
57 #define ZFL_VERSION     0x02    /* 16   */
58 #define CONTROL         0x10    /* 16   */
59 #define STATUS          0x12    /* 8    */
60 #define COUNTER_1       0x0C    /* 16   */
61 #define COUNTER_2       0x0E    /* 8    */
62 #define PULSE_LEN       0x0F    /* 8    */
63
64 /* controls */
65 #define ENABLE_WD1      0x0001
66 #define ENABLE_WD2      0x0002
67 #define RESET_WD1       0x0010
68 #define RESET_WD2       0x0020
69 #define GEN_SCI         0x0100
70 #define GEN_NMI         0x0200
71 #define GEN_SMI         0x0400
72 #define GEN_RESET       0x0800
73
74
75 /* utilities */
76
77 #define WD1     0
78 #define WD2     1
79
80 #define zf_writew(port, data)  { outb(port, INDEX); outw(data, DATA_W); }
81 #define zf_writeb(port, data)  { outb(port, INDEX); outb(data, DATA_B); }
82 #define zf_get_ZFL_version()   zf_readw(ZFL_VERSION)
83
84
85 static unsigned short zf_readw(unsigned char port)
86 {
87         outb(port, INDEX);
88         return inw(DATA_W);
89 }
90
91
92 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
93 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
94 MODULE_LICENSE("GPL");
95 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
96
97 static int nowayout = WATCHDOG_NOWAYOUT;
98 module_param(nowayout, int, 0);
99 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
100
101 #define PFX "machzwd"
102
103 static struct watchdog_info zf_info = {
104         .options                = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
105         .firmware_version       = 1,
106         .identity               = "ZF-Logic watchdog",
107 };
108
109
110 /*
111  * action refers to action taken when watchdog resets
112  * 0 = GEN_RESET
113  * 1 = GEN_SMI
114  * 2 = GEN_NMI
115  * 3 = GEN_SCI
116  * defaults to GEN_RESET (0)
117  */
118 static int action = 0;
119 module_param(action, int, 0);
120 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*)  1 = SMI  2 = NMI  3 = SCI");
121
122 static int zf_action = GEN_RESET;
123 static unsigned long zf_is_open;
124 static char zf_expect_close;
125 static spinlock_t zf_lock;
126 static spinlock_t zf_port_lock;
127 static struct timer_list zf_timer;
128 static unsigned long next_heartbeat = 0;
129
130
131 /* timeout for user land heart beat (10 seconds) */
132 #define ZF_USER_TIMEO (HZ*10)
133
134 /* timeout for hardware watchdog (~500ms) */
135 #define ZF_HW_TIMEO (HZ/2)
136
137 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
138 #define ZF_CTIMEOUT 0xffff
139
140 #ifndef ZF_DEBUG
141 #       define dprintk(format, args...)
142 #else
143 #       define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
144 #endif
145
146
147 static inline void zf_set_status(unsigned char new)
148 {
149         zf_writeb(STATUS, new);
150 }
151
152
153 /* CONTROL register functions */
154
155 static inline unsigned short zf_get_control(void)
156 {
157         return zf_readw(CONTROL);
158 }
159
160 static inline void zf_set_control(unsigned short new)
161 {
162         zf_writew(CONTROL, new);
163 }
164
165
166 /* WD#? counter functions */
167 /*
168  *      Just set counter value
169  */
170
171 static inline void zf_set_timer(unsigned short new, unsigned char n)
172 {
173         switch(n){
174                 case WD1:
175                         zf_writew(COUNTER_1, new);
176                 case WD2:
177                         zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
178                 default:
179                         return;
180         }
181 }
182
183 /*
184  * stop hardware timer
185  */
186 static void zf_timer_off(void)
187 {
188         unsigned int ctrl_reg = 0;
189         unsigned long flags;
190
191         /* stop internal ping */
192         del_timer_sync(&zf_timer);
193
194         spin_lock_irqsave(&zf_port_lock, flags);
195         /* stop watchdog timer */
196         ctrl_reg = zf_get_control();
197         ctrl_reg |= (ENABLE_WD1|ENABLE_WD2);    /* disable wd1 and wd2 */
198         ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
199         zf_set_control(ctrl_reg);
200         spin_unlock_irqrestore(&zf_port_lock, flags);
201
202         printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
203 }
204
205
206 /*
207  * start hardware timer
208  */
209 static void zf_timer_on(void)
210 {
211         unsigned int ctrl_reg = 0;
212         unsigned long flags;
213
214         spin_lock_irqsave(&zf_port_lock, flags);
215
216         zf_writeb(PULSE_LEN, 0xff);
217
218         zf_set_timer(ZF_CTIMEOUT, WD1);
219
220         /* user land ping */
221         next_heartbeat = jiffies + ZF_USER_TIMEO;
222
223         /* start the timer for internal ping */
224         zf_timer.expires = jiffies + ZF_HW_TIMEO;
225
226         add_timer(&zf_timer);
227
228         /* start watchdog timer */
229         ctrl_reg = zf_get_control();
230         ctrl_reg |= (ENABLE_WD1|zf_action);
231         zf_set_control(ctrl_reg);
232         spin_unlock_irqrestore(&zf_port_lock, flags);
233
234         printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
235 }
236
237
238 static void zf_ping(unsigned long data)
239 {
240         unsigned int ctrl_reg = 0;
241         unsigned long flags;
242
243         zf_writeb(COUNTER_2, 0xff);
244
245         if(time_before(jiffies, next_heartbeat)){
246
247                 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
248
249                 /*
250                  * reset event is activated by transition from 0 to 1 on
251                  * RESET_WD1 bit and we assume that it is already zero...
252                  */
253
254                 spin_lock_irqsave(&zf_port_lock, flags);
255                 ctrl_reg = zf_get_control();
256                 ctrl_reg |= RESET_WD1;
257                 zf_set_control(ctrl_reg);
258
259                 /* ...and nothing changes until here */
260                 ctrl_reg &= ~(RESET_WD1);
261                 zf_set_control(ctrl_reg);
262                 spin_unlock_irqrestore(&zf_port_lock, flags);
263
264                 zf_timer.expires = jiffies + ZF_HW_TIMEO;
265                 add_timer(&zf_timer);
266         }else{
267                 printk(KERN_CRIT PFX ": I will reset your machine\n");
268         }
269 }
270
271 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
272                                                                 loff_t *ppos)
273 {
274         /* See if we got the magic character */
275         if(count){
276
277                 /*
278                  * no need to check for close confirmation
279                  * no way to disable watchdog ;)
280                  */
281                 if (!nowayout) {
282                         size_t ofs;
283
284                         /*
285                          * note: just in case someone wrote the magic character
286                          * five months ago...
287                          */
288                         zf_expect_close = 0;
289
290                         /* now scan */
291                         for (ofs = 0; ofs != count; ofs++){
292                                 char c;
293                                 if (get_user(c, buf + ofs))
294                                         return -EFAULT;
295                                 if (c == 'V'){
296                                         zf_expect_close = 42;
297                                         dprintk("zf_expect_close = 42\n");
298                                 }
299                         }
300                 }
301
302                 /*
303                  * Well, anyhow someone wrote to us,
304                  * we should return that favour
305                  */
306                 next_heartbeat = jiffies + ZF_USER_TIMEO;
307                 dprintk("user ping at %ld\n", jiffies);
308
309         }
310
311         return count;
312 }
313
314 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
315         unsigned long arg)
316 {
317         void __user *argp = (void __user *)arg;
318         int __user *p = argp;
319         switch(cmd){
320                 case WDIOC_GETSUPPORT:
321                         if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
322                                 return -EFAULT;
323                         break;
324
325                 case WDIOC_GETSTATUS:
326                         return put_user(0, p);
327
328                 case WDIOC_KEEPALIVE:
329                         zf_ping(0);
330                         break;
331
332                 default:
333                         return -ENOIOCTLCMD;
334         }
335
336         return 0;
337 }
338
339 static int zf_open(struct inode *inode, struct file *file)
340 {
341         spin_lock(&zf_lock);
342         if(test_and_set_bit(0, &zf_is_open)) {
343                 spin_unlock(&zf_lock);
344                 return -EBUSY;
345         }
346
347         if (nowayout)
348                 __module_get(THIS_MODULE);
349
350         spin_unlock(&zf_lock);
351
352         zf_timer_on();
353
354         return nonseekable_open(inode, file);
355 }
356
357 static int zf_close(struct inode *inode, struct file *file)
358 {
359         if(zf_expect_close == 42){
360                 zf_timer_off();
361         } else {
362                 del_timer(&zf_timer);
363                 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
364         }
365
366         spin_lock(&zf_lock);
367         clear_bit(0, &zf_is_open);
368         spin_unlock(&zf_lock);
369
370         zf_expect_close = 0;
371
372         return 0;
373 }
374
375 /*
376  * Notifier for system down
377  */
378
379 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
380                                                                 void *unused)
381 {
382         if(code == SYS_DOWN || code == SYS_HALT){
383                 zf_timer_off();
384         }
385
386         return NOTIFY_DONE;
387 }
388
389
390
391
392 static struct file_operations zf_fops = {
393         .owner          = THIS_MODULE,
394         .llseek         = no_llseek,
395         .write          = zf_write,
396         .ioctl          = zf_ioctl,
397         .open           = zf_open,
398         .release        = zf_close,
399 };
400
401 static struct miscdevice zf_miscdev = {
402         .minor = WATCHDOG_MINOR,
403         .name = "watchdog",
404         .fops = &zf_fops,
405 };
406  
407
408 /*
409  * The device needs to learn about soft shutdowns in order to
410  * turn the timebomb registers off.
411  */
412 static struct notifier_block zf_notifier = {
413         .notifier_call = zf_notify_sys,
414 };
415
416 static void __init zf_show_action(int act)
417 {
418         char *str[] = { "RESET", "SMI", "NMI", "SCI" };
419
420         printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
421 }
422
423 static int __init zf_init(void)
424 {
425         int ret;
426
427         printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
428
429         ret = zf_get_ZFL_version();
430         printk("%#x\n", ret);
431         if((!ret) || (ret != 0xffff)){
432                 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
433                 return -ENODEV;
434         }
435
436         if((action <= 3) && (action >= 0)){
437                 zf_action = zf_action>>action;
438         } else
439                 action = 0;
440
441         zf_show_action(action);
442
443         spin_lock_init(&zf_lock);
444         spin_lock_init(&zf_port_lock);
445
446         ret = misc_register(&zf_miscdev);
447         if (ret){
448                 printk(KERN_ERR "can't misc_register on minor=%d\n",
449                                                         WATCHDOG_MINOR);
450                 goto out;
451         }
452
453         if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
454                 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
455                                                         ZF_IOBASE);
456                 ret = -EBUSY;
457                 goto no_region;
458         }
459
460         ret = register_reboot_notifier(&zf_notifier);
461         if(ret){
462                 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
463                                                                         ret);
464                 goto no_reboot;
465         }
466
467         zf_set_status(0);
468         zf_set_control(0);
469
470         /* this is the timer that will do the hard work */
471         init_timer(&zf_timer);
472         zf_timer.function = zf_ping;
473         zf_timer.data = 0;
474
475         return 0;
476
477 no_reboot:
478         release_region(ZF_IOBASE, 3);
479 no_region:
480         misc_deregister(&zf_miscdev);
481 out:
482         return ret;
483 }
484
485
486 static void __exit zf_exit(void)
487 {
488         zf_timer_off();
489
490         misc_deregister(&zf_miscdev);
491         unregister_reboot_notifier(&zf_notifier);
492         release_region(ZF_IOBASE, 3);
493 }
494
495 module_init(zf_init);
496 module_exit(zf_exit);