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/version.h>
34 #include <linux/types.h>
35 #include <linux/errno.h>
36 #include <linux/kernel.h>
37 #include <linux/timer.h>
38 #include <linux/sched.h>
39 #include <linux/miscdevice.h>
40 #include <linux/watchdog.h>
41 #include <linux/slab.h>
42 #include <linux/ioport.h>
43 #include <linux/fcntl.h>
44 #include <linux/smp_lock.h>
45 #include <asm/io.h>
46 #include <asm/uaccess.h>
47 #include <asm/system.h>
48 #include <linux/notifier.h>
49 #include <linux/reboot.h>
50 #include <linux/init.h>
51
52
53 /* ports */
54 #define ZF_IOBASE 0x218
55 #define INDEX 0x218
56 #define DATA_B 0x219
57 #define DATA_W 0x21A
58 #define DATA_D 0x21A
59
60 /* indexes */ /* size */
61 #define ZFL_VERSION 0x02 /* 16 */
62 #define CONTROL 0x10 /* 16 */
63 #define STATUS 0x12 /* 8 */
64 #define COUNTER_1 0x0C /* 16 */
65 #define COUNTER_2 0x0E /* 8 */
66 #define PULSE_LEN 0x0F /* 8 */
67
68 /* controls */
69 #define ENABLE_WD1 0x0001
70 #define ENABLE_WD2 0x0002
71 #define RESET_WD1 0x0010
72 #define RESET_WD2 0x0020
73 #define GEN_SCI 0x0100
74 #define GEN_NMI 0x0200
75 #define GEN_SMI 0x0400
76 #define GEN_RESET 0x0800
77
78
79 /* utilities */
80
81 #define WD1 0
82 #define WD2 1
83
84 #define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
85 #define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
86 #define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
87
88
zf_readw(unsigned char port)89 static unsigned short zf_readw(unsigned char port)
90 {
91 outb(port, INDEX);
92 return inw(DATA_W);
93 }
94
zf_readb(unsigned char port)95 static unsigned short zf_readb(unsigned char port)
96 {
97 outb(port, INDEX);
98 return inb(DATA_B);
99 }
100
101
102 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
103 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
104 MODULE_LICENSE("GPL");
105 MODULE_PARM(action, "i");
106 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
107
108 #ifdef CONFIG_WATCHDOG_NOWAYOUT
109 static int nowayout = 1;
110 #else
111 static int nowayout = 0;
112 #endif
113
114 MODULE_PARM(nowayout,"i");
115 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
116
117 #define PFX "machzwd"
118
119 static struct watchdog_info zf_info = {
120 options: WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
121 firmware_version: 1,
122 identity: "ZF-Logic watchdog"
123 };
124
125
126 /*
127 * action refers to action taken when watchdog resets
128 * 0 = GEN_RESET
129 * 1 = GEN_SMI
130 * 2 = GEN_NMI
131 * 3 = GEN_SCI
132 * defaults to GEN_RESET (0)
133 */
134 static int action = 0;
135 static int zf_action = GEN_RESET;
136 static int zf_is_open = 0;
137 static int zf_expect_close = 0;
138 static spinlock_t zf_lock;
139 static spinlock_t zf_port_lock;
140 static struct timer_list zf_timer;
141 static unsigned long next_heartbeat = 0;
142
143
144 /* timeout for user land heart beat (10 seconds) */
145 #define ZF_USER_TIMEO (HZ*10)
146
147 /* timeout for hardware watchdog (~500ms) */
148 #define ZF_HW_TIMEO (HZ/2)
149
150 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
151 #define ZF_CTIMEOUT 0xffff
152
153 #ifndef ZF_DEBUG
154 # define dprintk(format, args...)
155 #else
156 # define dprintk(format, args...) printk(KERN_DEBUG PFX; ":" __FUNCTION__ ":%d: " format, __LINE__ , ## args)
157 #endif
158
159
160 /* STATUS register functions */
161
zf_get_status(void)162 static inline unsigned char zf_get_status(void)
163 {
164 return zf_readb(STATUS);
165 }
166
zf_set_status(unsigned char new)167 static inline void zf_set_status(unsigned char new)
168 {
169 zf_writeb(STATUS, new);
170 }
171
172
173 /* CONTROL register functions */
174
zf_get_control(void)175 static inline unsigned short zf_get_control(void)
176 {
177 return zf_readw(CONTROL);
178 }
179
zf_set_control(unsigned short new)180 static inline void zf_set_control(unsigned short new)
181 {
182 zf_writew(CONTROL, new);
183 }
184
185
186 /* WD#? counter functions */
187 /*
188 * Just get current counter value
189 */
190
zf_get_timer(unsigned char n)191 static inline unsigned short zf_get_timer(unsigned char n)
192 {
193 switch(n){
194 case WD1:
195 return zf_readw(COUNTER_1);
196 case WD2:
197 return zf_readb(COUNTER_2);
198 default:
199 return 0;
200 }
201 }
202
203 /*
204 * Just set counter value
205 */
206
zf_set_timer(unsigned short new,unsigned char n)207 static inline void zf_set_timer(unsigned short new, unsigned char n)
208 {
209 switch(n){
210 case WD1:
211 zf_writew(COUNTER_1, new);
212 case WD2:
213 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
214 default:
215 return;
216 }
217 }
218
219 /*
220 * stop hardware timer
221 */
zf_timer_off(void)222 static void zf_timer_off(void)
223 {
224 unsigned int ctrl_reg = 0;
225 unsigned long flags;
226
227 /* stop internal ping */
228 del_timer_sync(&zf_timer);
229
230 spin_lock_irqsave(&zf_port_lock, flags);
231 /* stop watchdog timer */
232 ctrl_reg = zf_get_control();
233 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
234 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
235 zf_set_control(ctrl_reg);
236 spin_unlock_irqrestore(&zf_port_lock, flags);
237
238 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
239 }
240
241
242 /*
243 * start hardware timer
244 */
zf_timer_on(void)245 static void zf_timer_on(void)
246 {
247 unsigned int ctrl_reg = 0;
248 unsigned long flags;
249
250 spin_lock_irqsave(&zf_port_lock, flags);
251
252 zf_writeb(PULSE_LEN, 0xff);
253
254 zf_set_timer(ZF_CTIMEOUT, WD1);
255
256 /* user land ping */
257 next_heartbeat = jiffies + ZF_USER_TIMEO;
258
259 /* start the timer for internal ping */
260 zf_timer.expires = jiffies + ZF_HW_TIMEO;
261
262 add_timer(&zf_timer);
263
264 /* start watchdog timer */
265 ctrl_reg = zf_get_control();
266 ctrl_reg |= (ENABLE_WD1|zf_action);
267 zf_set_control(ctrl_reg);
268 spin_unlock_irqrestore(&zf_port_lock, flags);
269
270 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
271 }
272
273
zf_ping(unsigned long data)274 static void zf_ping(unsigned long data)
275 {
276 unsigned int ctrl_reg = 0;
277 unsigned long flags;
278
279 zf_writeb(COUNTER_2, 0xff);
280
281 if(time_before(jiffies, next_heartbeat)){
282
283 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
284
285 /*
286 * reset event is activated by transition from 0 to 1 on
287 * RESET_WD1 bit and we assume that it is already zero...
288 */
289
290 spin_lock_irqsave(&zf_port_lock, flags);
291 ctrl_reg = zf_get_control();
292 ctrl_reg |= RESET_WD1;
293 zf_set_control(ctrl_reg);
294
295 /* ...and nothing changes until here */
296 ctrl_reg &= ~(RESET_WD1);
297 zf_set_control(ctrl_reg);
298 spin_unlock_irqrestore(&zf_port_lock, flags);
299
300 zf_timer.expires = jiffies + ZF_HW_TIMEO;
301 add_timer(&zf_timer);
302 }else{
303 printk(KERN_CRIT PFX ": I will reset your machine\n");
304 }
305 }
306
zf_write(struct file * file,const char * buf,size_t count,loff_t * ppos)307 static ssize_t zf_write(struct file *file, const char *buf, size_t count,
308 loff_t *ppos)
309 {
310 /* Can't seek (pwrite) on this device */
311 if (ppos != &file->f_pos)
312 return -ESPIPE;
313
314 /* See if we got the magic character */
315 if(count){
316
317 /*
318 * no need to check for close confirmation
319 * no way to disable watchdog ;)
320 */
321 if (!nowayout) {
322 size_t ofs;
323
324 /*
325 * note: just in case someone wrote the
326 * magic character five months ago...
327 */
328 zf_expect_close = 0;
329
330 /* now scan */
331 for(ofs = 0; ofs != count; ofs++){
332 char c;
333 if(get_user(c, buf+ofs))
334 return -EFAULT;
335 if(c == 'V'){
336 zf_expect_close = 1;
337 dprintk("zf_expect_close 1\n");
338 }
339 }
340 }
341 /*
342 * Well, anyhow someone wrote to us,
343 * we should return that favour
344 */
345 next_heartbeat = jiffies + ZF_USER_TIMEO;
346 dprintk("user ping at %ld\n", jiffies);
347
348 return 1;
349 }
350
351 return 0;
352 }
353
zf_read(struct file * file,char * buf,size_t count,loff_t * ppos)354 static ssize_t zf_read(struct file *file, char *buf, size_t count,
355 loff_t *ppos)
356 {
357 return -EINVAL;
358 }
359
360
361
zf_ioctl(struct inode * inode,struct file * file,unsigned int cmd,unsigned long arg)362 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
363 unsigned long arg)
364 {
365 switch(cmd){
366 case WDIOC_GETSUPPORT:
367 if (copy_to_user((struct watchdog_info *)arg,
368 &zf_info, sizeof(zf_info)))
369 return -EFAULT;
370 break;
371
372 case WDIOC_GETSTATUS:
373 if (copy_to_user((int *)arg, &zf_is_open, sizeof(int)))
374 return -EFAULT;
375 break;
376
377 case WDIOC_KEEPALIVE:
378 zf_ping(0);
379 break;
380
381 default:
382 return -ENOTTY;
383 }
384
385 return 0;
386 }
387
zf_open(struct inode * inode,struct file * file)388 static int zf_open(struct inode *inode, struct file *file)
389 {
390 switch(MINOR(inode->i_rdev)){
391 case WATCHDOG_MINOR:
392 spin_lock(&zf_lock);
393 if(zf_is_open){
394 spin_unlock(&zf_lock);
395 return -EBUSY;
396 }
397
398 if (nowayout) {
399 MOD_INC_USE_COUNT;
400 }
401 zf_is_open = 1;
402
403 spin_unlock(&zf_lock);
404
405 zf_timer_on();
406
407 return 0;
408 default:
409 return -ENODEV;
410 }
411 }
412
zf_close(struct inode * inode,struct file * file)413 static int zf_close(struct inode *inode, struct file *file)
414 {
415 if(MINOR(inode->i_rdev) == WATCHDOG_MINOR){
416
417 if(zf_expect_close){
418 zf_timer_off();
419 } else {
420 del_timer(&zf_timer);
421 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
422 }
423
424 spin_lock(&zf_lock);
425 zf_is_open = 0;
426 spin_unlock(&zf_lock);
427
428 zf_expect_close = 0;
429 }
430
431 return 0;
432 }
433
434 /*
435 * Notifier for system down
436 */
437
zf_notify_sys(struct notifier_block * this,unsigned long code,void * unused)438 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
439 void *unused)
440 {
441 if(code == SYS_DOWN || code == SYS_HALT){
442 zf_timer_off();
443 }
444
445 return NOTIFY_DONE;
446 }
447
448
449
450
451 static struct file_operations zf_fops = {
452 owner: THIS_MODULE,
453 read: zf_read,
454 write: zf_write,
455 ioctl: zf_ioctl,
456 open: zf_open,
457 release: zf_close,
458 };
459
460 static struct miscdevice zf_miscdev = {
461 WATCHDOG_MINOR,
462 "watchdog",
463 &zf_fops
464 };
465
466
467 /*
468 * The device needs to learn about soft shutdowns in order to
469 * turn the timebomb registers off.
470 */
471 static struct notifier_block zf_notifier = {
472 zf_notify_sys,
473 NULL,
474 0
475 };
476
zf_show_action(int act)477 static void __init zf_show_action(int act)
478 {
479 char *str[] = { "RESET", "SMI", "NMI", "SCI" };
480
481 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
482 }
483
zf_init(void)484 static int __init zf_init(void)
485 {
486 int ret;
487
488 printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
489
490 ret = zf_get_ZFL_version();
491 printk("%#x\n", ret);
492 if((!ret) || (ret != 0xffff)){
493 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
494 return -ENODEV;
495 }
496
497 if((action <= 3) && (action >= 0)){
498 zf_action = zf_action>>action;
499 } else
500 action = 0;
501
502 zf_show_action(action);
503
504 spin_lock_init(&zf_lock);
505 spin_lock_init(&zf_port_lock);
506
507 ret = misc_register(&zf_miscdev);
508 if (ret){
509 printk(KERN_ERR "can't misc_register on minor=%d\n",
510 WATCHDOG_MINOR);
511 goto out;
512 }
513
514 if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
515 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
516 ZF_IOBASE);
517 ret = -EBUSY;
518 goto no_region;
519 }
520
521 ret = register_reboot_notifier(&zf_notifier);
522 if(ret){
523 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
524 ret);
525 goto no_reboot;
526 }
527
528 zf_set_status(0);
529 zf_set_control(0);
530
531 /* this is the timer that will do the hard work */
532 init_timer(&zf_timer);
533 zf_timer.function = zf_ping;
534 zf_timer.data = 0;
535
536 return 0;
537
538 no_reboot:
539 release_region(ZF_IOBASE, 3);
540 no_region:
541 misc_deregister(&zf_miscdev);
542 out:
543 return ret;
544 }
545
546
zf_exit(void)547 void __exit zf_exit(void)
548 {
549 zf_timer_off();
550
551 misc_deregister(&zf_miscdev);
552 unregister_reboot_notifier(&zf_notifier);
553 release_region(ZF_IOBASE, 3);
554 }
555
556 module_init(zf_init);
557 module_exit(zf_exit);
558