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 #ifdef CONFIG_WATCHDOG_NOWAYOUT
98 static int nowayout = 1;
99 #else
100 static int nowayout = 0;
101 #endif
102
103 module_param(nowayout, int, 0);
104 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
105
106 #define PFX "machzwd"
107
108 static struct watchdog_info zf_info = {
109 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
110 .firmware_version = 1,
111 .identity = "ZF-Logic watchdog",
112 };
113
114
115 /*
116 * action refers to action taken when watchdog resets
117 * 0 = GEN_RESET
118 * 1 = GEN_SMI
119 * 2 = GEN_NMI
120 * 3 = GEN_SCI
121 * defaults to GEN_RESET (0)
122 */
123 static int action = 0;
124 module_param(action, int, 0);
125 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
126
127 static int zf_action = GEN_RESET;
128 static unsigned long zf_is_open;
129 static char zf_expect_close;
130 static spinlock_t zf_lock;
131 static spinlock_t zf_port_lock;
132 static struct timer_list zf_timer;
133 static unsigned long next_heartbeat = 0;
134
135
136 /* timeout for user land heart beat (10 seconds) */
137 #define ZF_USER_TIMEO (HZ*10)
138
139 /* timeout for hardware watchdog (~500ms) */
140 #define ZF_HW_TIMEO (HZ/2)
141
142 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
143 #define ZF_CTIMEOUT 0xffff
144
145 #ifndef ZF_DEBUG
146 # define dprintk(format, args...)
147 #else
148 # define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
149 #endif
150
151
152 static inline void zf_set_status(unsigned char new)
153 {
154 zf_writeb(STATUS, new);
155 }
156
157
158 /* CONTROL register functions */
159
160 static inline unsigned short zf_get_control(void)
161 {
162 return zf_readw(CONTROL);
163 }
164
165 static inline void zf_set_control(unsigned short new)
166 {
167 zf_writew(CONTROL, new);
168 }
169
170
171 /* WD#? counter functions */
172 /*
173 * Just set counter value
174 */
175
176 static inline void zf_set_timer(unsigned short new, unsigned char n)
177 {
178 switch(n){
179 case WD1:
180 zf_writew(COUNTER_1, new);
181 case WD2:
182 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
183 default:
184 return;
185 }
186 }
187
188 /*
189 * stop hardware timer
190 */
191 static void zf_timer_off(void)
192 {
193 unsigned int ctrl_reg = 0;
194 unsigned long flags;
195
196 /* stop internal ping */
197 del_timer_sync(&zf_timer);
198
199 spin_lock_irqsave(&zf_port_lock, flags);
200 /* stop watchdog timer */
201 ctrl_reg = zf_get_control();
202 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
203 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
204 zf_set_control(ctrl_reg);
205 spin_unlock_irqrestore(&zf_port_lock, flags);
206
207 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
208 }
209
210
211 /*
212 * start hardware timer
213 */
214 static void zf_timer_on(void)
215 {
216 unsigned int ctrl_reg = 0;
217 unsigned long flags;
218
219 spin_lock_irqsave(&zf_port_lock, flags);
220
221 zf_writeb(PULSE_LEN, 0xff);
222
223 zf_set_timer(ZF_CTIMEOUT, WD1);
224
225 /* user land ping */
226 next_heartbeat = jiffies + ZF_USER_TIMEO;
227
228 /* start the timer for internal ping */
229 zf_timer.expires = jiffies + ZF_HW_TIMEO;
230
231 add_timer(&zf_timer);
232
233 /* start watchdog timer */
234 ctrl_reg = zf_get_control();
235 ctrl_reg |= (ENABLE_WD1|zf_action);
236 zf_set_control(ctrl_reg);
237 spin_unlock_irqrestore(&zf_port_lock, flags);
238
239 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
240 }
241
242
243 static void zf_ping(unsigned long data)
244 {
245 unsigned int ctrl_reg = 0;
246 unsigned long flags;
247
248 zf_writeb(COUNTER_2, 0xff);
249
250 if(time_before(jiffies, next_heartbeat)){
251
252 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
253
254 /*
255 * reset event is activated by transition from 0 to 1 on
256 * RESET_WD1 bit and we assume that it is already zero...
257 */
258
259 spin_lock_irqsave(&zf_port_lock, flags);
260 ctrl_reg = zf_get_control();
261 ctrl_reg |= RESET_WD1;
262 zf_set_control(ctrl_reg);
263
264 /* ...and nothing changes until here */
265 ctrl_reg &= ~(RESET_WD1);
266 zf_set_control(ctrl_reg);
267 spin_unlock_irqrestore(&zf_port_lock, flags);
268
269 zf_timer.expires = jiffies + ZF_HW_TIMEO;
270 add_timer(&zf_timer);
271 }else{
272 printk(KERN_CRIT PFX ": I will reset your machine\n");
273 }
274 }
275
276 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
277 loff_t *ppos)
278 {
279 /* See if we got the magic character */
280 if(count){
281
282 /*
283 * no need to check for close confirmation
284 * no way to disable watchdog ;)
285 */
286 if (!nowayout) {
287 size_t ofs;
288
289 /*
290 * note: just in case someone wrote the magic character
291 * five months ago...
292 */
293 zf_expect_close = 0;
294
295 /* now scan */
296 for (ofs = 0; ofs != count; ofs++){
297 char c;
298 if (get_user(c, buf + ofs))
299 return -EFAULT;
300 if (c == 'V'){
301 zf_expect_close = 42;
302 dprintk("zf_expect_close = 42\n");
303 }
304 }
305 }
306
307 /*
308 * Well, anyhow someone wrote to us,
309 * we should return that favour
310 */
311 next_heartbeat = jiffies + ZF_USER_TIMEO;
312 dprintk("user ping at %ld\n", jiffies);
313
314 }
315
316 return count;
317 }
318
319 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
320 unsigned long arg)
321 {
322 void __user *argp = (void __user *)arg;
323 int __user *p = argp;
324 switch(cmd){
325 case WDIOC_GETSUPPORT:
326 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
327 return -EFAULT;
328 break;
329
330 case WDIOC_GETSTATUS:
331 return put_user(0, p);
332
333 case WDIOC_KEEPALIVE:
334 zf_ping(0);
335 break;
336
337 default:
338 return -ENOIOCTLCMD;
339 }
340
341 return 0;
342 }
343
344 static int zf_open(struct inode *inode, struct file *file)
345 {
346 spin_lock(&zf_lock);
347 if(test_and_set_bit(0, &zf_is_open)) {
348 spin_unlock(&zf_lock);
349 return -EBUSY;
350 }
351
352 if (nowayout)
353 __module_get(THIS_MODULE);
354
355 spin_unlock(&zf_lock);
356
357 zf_timer_on();
358
359 return nonseekable_open(inode, file);
360 }
361
362 static int zf_close(struct inode *inode, struct file *file)
363 {
364 if(zf_expect_close == 42){
365 zf_timer_off();
366 } else {
367 del_timer(&zf_timer);
368 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
369 }
370
371 spin_lock(&zf_lock);
372 clear_bit(0, &zf_is_open);
373 spin_unlock(&zf_lock);
374
375 zf_expect_close = 0;
376
377 return 0;
378 }
379
380 /*
381 * Notifier for system down
382 */
383
384 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
385 void *unused)
386 {
387 if(code == SYS_DOWN || code == SYS_HALT){
388 zf_timer_off();
389 }
390
391 return NOTIFY_DONE;
392 }
393
394
395
396
397 static struct file_operations zf_fops = {
398 .owner = THIS_MODULE,
399 .llseek = no_llseek,
400 .write = zf_write,
401 .ioctl = zf_ioctl,
402 .open = zf_open,
403 .release = zf_close,
404 };
405
406 static struct miscdevice zf_miscdev = {
407 .minor = WATCHDOG_MINOR,
408 .name = "watchdog",
409 .fops = &zf_fops,
410 };
411
412
413 /*
414 * The device needs to learn about soft shutdowns in order to
415 * turn the timebomb registers off.
416 */
417 static struct notifier_block zf_notifier = {
418 .notifier_call = zf_notify_sys,
419 };
420
421 static void __init zf_show_action(int act)
422 {
423 char *str[] = { "RESET", "SMI", "NMI", "SCI" };
424
425 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
426 }
427
428 static int __init zf_init(void)
429 {
430 int ret;
431
432 printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
433
434 ret = zf_get_ZFL_version();
435 printk("%#x\n", ret);
436 if((!ret) || (ret != 0xffff)){
437 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
438 return -ENODEV;
439 }
440
441 if((action <= 3) && (action >= 0)){
442 zf_action = zf_action>>action;
443 } else
444 action = 0;
445
446 zf_show_action(action);
447
448 spin_lock_init(&zf_lock);
449 spin_lock_init(&zf_port_lock);
450
451 ret = misc_register(&zf_miscdev);
452 if (ret){
453 printk(KERN_ERR "can't misc_register on minor=%d\n",
454 WATCHDOG_MINOR);
455 goto out;
456 }
457
458 if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
459 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
460 ZF_IOBASE);
461 ret = -EBUSY;
462 goto no_region;
463 }
464
465 ret = register_reboot_notifier(&zf_notifier);
466 if(ret){
467 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
468 ret);
469 goto no_reboot;
470 }
471
472 zf_set_status(0);
473 zf_set_control(0);
474
475 /* this is the timer that will do the hard work */
476 init_timer(&zf_timer);
477 zf_timer.function = zf_ping;
478 zf_timer.data = 0;
479
480 return 0;
481
482 no_reboot:
483 release_region(ZF_IOBASE, 3);
484 no_region:
485 misc_deregister(&zf_miscdev);
486 out:
487 return ret;
488 }
489
490
491 void __exit zf_exit(void)
492 {
493 zf_timer_off();
494
495 misc_deregister(&zf_miscdev);
496 unregister_reboot_notifier(&zf_notifier);
497 release_region(ZF_IOBASE, 3);
498 }
499
500 module_init(zf_init);
501 module_exit(zf_exit);
502
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