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);
497
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