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=" __MODULE_STRING(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 void zf_ping(unsigned long data);
122
123 static int zf_action = GEN_RESET;
124 static unsigned long zf_is_open;
125 static char zf_expect_close;
126 static DEFINE_SPINLOCK(zf_lock);
127 static DEFINE_SPINLOCK(zf_port_lock);
128 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
129 static unsigned long next_heartbeat = 0;
130
131
132 /* timeout for user land heart beat (10 seconds) */
133 #define ZF_USER_TIMEO (HZ*10)
134
135 /* timeout for hardware watchdog (~500ms) */
136 #define ZF_HW_TIMEO (HZ/2)
137
138 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
139 #define ZF_CTIMEOUT 0xffff
140
141 #ifndef ZF_DEBUG
142 # define dprintk(format, args...)
143 #else
144 # define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __func__, __LINE__ , ## args)
145 #endif
146
147
148 static inline void zf_set_status(unsigned char new)
149 {
150 zf_writeb(STATUS, new);
151 }
152
153
154 /* CONTROL register functions */
155
156 static inline unsigned short zf_get_control(void)
157 {
158 return zf_readw(CONTROL);
159 }
160
161 static inline void zf_set_control(unsigned short new)
162 {
163 zf_writew(CONTROL, new);
164 }
165
166
167 /* WD#? counter functions */
168 /*
169 * Just set counter value
170 */
171
172 static inline void zf_set_timer(unsigned short new, unsigned char n)
173 {
174 switch(n){
175 case WD1:
176 zf_writew(COUNTER_1, new);
177 case WD2:
178 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
179 default:
180 return;
181 }
182 }
183
184 /*
185 * stop hardware timer
186 */
187 static void zf_timer_off(void)
188 {
189 unsigned int ctrl_reg = 0;
190 unsigned long flags;
191
192 /* stop internal ping */
193 del_timer_sync(&zf_timer);
194
195 spin_lock_irqsave(&zf_port_lock, flags);
196 /* stop watchdog timer */
197 ctrl_reg = zf_get_control();
198 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
199 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
200 zf_set_control(ctrl_reg);
201 spin_unlock_irqrestore(&zf_port_lock, flags);
202
203 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
204 }
205
206
207 /*
208 * start hardware timer
209 */
210 static void zf_timer_on(void)
211 {
212 unsigned int ctrl_reg = 0;
213 unsigned long flags;
214
215 spin_lock_irqsave(&zf_port_lock, flags);
216
217 zf_writeb(PULSE_LEN, 0xff);
218
219 zf_set_timer(ZF_CTIMEOUT, WD1);
220
221 /* user land ping */
222 next_heartbeat = jiffies + ZF_USER_TIMEO;
223
224 /* start the timer for internal ping */
225 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
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 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
264 }else{
265 printk(KERN_CRIT PFX ": I will reset your machine\n");
266 }
267 }
268
269 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
270 loff_t *ppos)
271 {
272 /* See if we got the magic character */
273 if(count){
274
275 /*
276 * no need to check for close confirmation
277 * no way to disable watchdog ;)
278 */
279 if (!nowayout) {
280 size_t ofs;
281
282 /*
283 * note: just in case someone wrote the magic character
284 * five months ago...
285 */
286 zf_expect_close = 0;
287
288 /* now scan */
289 for (ofs = 0; ofs != count; ofs++){
290 char c;
291 if (get_user(c, buf + ofs))
292 return -EFAULT;
293 if (c == 'V'){
294 zf_expect_close = 42;
295 dprintk("zf_expect_close = 42\n");
296 }
297 }
298 }
299
300 /*
301 * Well, anyhow someone wrote to us,
302 * we should return that favour
303 */
304 next_heartbeat = jiffies + ZF_USER_TIMEO;
305 dprintk("user ping at %ld\n", jiffies);
306
307 }
308
309 return count;
310 }
311
312 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
313 unsigned long arg)
314 {
315 void __user *argp = (void __user *)arg;
316 int __user *p = argp;
317 switch (cmd) {
318 case WDIOC_GETSUPPORT:
319 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
320 return -EFAULT;
321 break;
322
323 case WDIOC_GETSTATUS:
324 case WDIOC_GETBOOTSTATUS:
325 return put_user(0, p);
326
327 case WDIOC_KEEPALIVE:
328 zf_ping(0);
329 break;
330
331 default:
332 return -ENOTTY;
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 if ((!ret) || (ret == 0xffff)) {
430 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
431 return -ENODEV;
432 }
433
434 if((action <= 3) && (action >= 0)){
435 zf_action = zf_action>>action;
436 } else
437 action = 0;
438
439 zf_show_action(action);
440
441 if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
442 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
443 ZF_IOBASE);
444 ret = -EBUSY;
445 goto no_region;
446 }
447
448 ret = register_reboot_notifier(&zf_notifier);
449 if(ret){
450 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
451 ret);
452 goto no_reboot;
453 }
454
455 ret = misc_register(&zf_miscdev);
456 if (ret){
457 printk(KERN_ERR "can't misc_register on minor=%d\n",
458 WATCHDOG_MINOR);
459 goto no_misc;
460 }
461
462 zf_set_status(0);
463 zf_set_control(0);
464
465 return 0;
466
467 no_misc:
468 unregister_reboot_notifier(&zf_notifier);
469 no_reboot:
470 release_region(ZF_IOBASE, 3);
471 no_region:
472 return ret;
473 }
474
475
476 static void __exit zf_exit(void)
477 {
478 zf_timer_off();
479
480 misc_deregister(&zf_miscdev);
481 unregister_reboot_notifier(&zf_notifier);
482 release_region(ZF_IOBASE, 3);
483 }
484
485 module_init(zf_init);
486 module_exit(zf_exit);
487
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