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1da177e4 LT |
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 | ||
1da177e4 LT |
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 | ||
4bfdf378 | 96 | static int nowayout = WATCHDOG_NOWAYOUT; |
1da177e4 | 97 | module_param(nowayout, int, 0); |
bffda5c8 | 98 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
1da177e4 LT |
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 | ||
82eb7c50 JS |
121 | static void zf_ping(unsigned long data); |
122 | ||
1da177e4 LT |
123 | static int zf_action = GEN_RESET; |
124 | static unsigned long zf_is_open; | |
125 | static char zf_expect_close; | |
126 | static spinlock_t zf_lock; | |
127 | static spinlock_t zf_port_lock; | |
82eb7c50 | 128 | static DEFINE_TIMER(zf_timer, zf_ping, 0, 0); |
1da177e4 LT |
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, __FUNCTION__, __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 */ | |
82eb7c50 | 225 | mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); |
1da177e4 LT |
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 | ||
82eb7c50 | 263 | mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO); |
1da177e4 LT |
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 | return put_user(0, p); | |
325 | ||
326 | case WDIOC_KEEPALIVE: | |
89952d13 | 327 | zf_ping(NULL); |
1da177e4 LT |
328 | break; |
329 | ||
330 | default: | |
795b89d2 | 331 | return -ENOTTY; |
1da177e4 LT |
332 | } |
333 | ||
334 | return 0; | |
335 | } | |
336 | ||
337 | static int zf_open(struct inode *inode, struct file *file) | |
338 | { | |
339 | spin_lock(&zf_lock); | |
340 | if(test_and_set_bit(0, &zf_is_open)) { | |
341 | spin_unlock(&zf_lock); | |
342 | return -EBUSY; | |
343 | } | |
344 | ||
345 | if (nowayout) | |
346 | __module_get(THIS_MODULE); | |
347 | ||
348 | spin_unlock(&zf_lock); | |
349 | ||
350 | zf_timer_on(); | |
351 | ||
352 | return nonseekable_open(inode, file); | |
353 | } | |
354 | ||
355 | static int zf_close(struct inode *inode, struct file *file) | |
356 | { | |
357 | if(zf_expect_close == 42){ | |
358 | zf_timer_off(); | |
359 | } else { | |
360 | del_timer(&zf_timer); | |
361 | printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n"); | |
362 | } | |
363 | ||
364 | spin_lock(&zf_lock); | |
365 | clear_bit(0, &zf_is_open); | |
366 | spin_unlock(&zf_lock); | |
367 | ||
368 | zf_expect_close = 0; | |
369 | ||
370 | return 0; | |
371 | } | |
372 | ||
373 | /* | |
374 | * Notifier for system down | |
375 | */ | |
376 | ||
377 | static int zf_notify_sys(struct notifier_block *this, unsigned long code, | |
378 | void *unused) | |
379 | { | |
380 | if(code == SYS_DOWN || code == SYS_HALT){ | |
381 | zf_timer_off(); | |
382 | } | |
383 | ||
384 | return NOTIFY_DONE; | |
385 | } | |
386 | ||
387 | ||
388 | ||
389 | ||
62322d25 | 390 | static const struct file_operations zf_fops = { |
1da177e4 LT |
391 | .owner = THIS_MODULE, |
392 | .llseek = no_llseek, | |
393 | .write = zf_write, | |
394 | .ioctl = zf_ioctl, | |
395 | .open = zf_open, | |
396 | .release = zf_close, | |
397 | }; | |
398 | ||
399 | static struct miscdevice zf_miscdev = { | |
400 | .minor = WATCHDOG_MINOR, | |
401 | .name = "watchdog", | |
402 | .fops = &zf_fops, | |
403 | }; | |
404 | ||
405 | ||
406 | /* | |
407 | * The device needs to learn about soft shutdowns in order to | |
408 | * turn the timebomb registers off. | |
409 | */ | |
410 | static struct notifier_block zf_notifier = { | |
411 | .notifier_call = zf_notify_sys, | |
412 | }; | |
413 | ||
414 | static void __init zf_show_action(int act) | |
415 | { | |
416 | char *str[] = { "RESET", "SMI", "NMI", "SCI" }; | |
417 | ||
418 | printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]); | |
419 | } | |
420 | ||
421 | static int __init zf_init(void) | |
422 | { | |
423 | int ret; | |
424 | ||
425 | printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n"); | |
426 | ||
427 | ret = zf_get_ZFL_version(); | |
11dc1019 | 428 | if ((!ret) || (ret == 0xffff)) { |
1da177e4 LT |
429 | printk(KERN_WARNING PFX ": no ZF-Logic found\n"); |
430 | return -ENODEV; | |
431 | } | |
432 | ||
433 | if((action <= 3) && (action >= 0)){ | |
434 | zf_action = zf_action>>action; | |
435 | } else | |
436 | action = 0; | |
437 | ||
438 | zf_show_action(action); | |
439 | ||
440 | spin_lock_init(&zf_lock); | |
441 | spin_lock_init(&zf_port_lock); | |
442 | ||
443 | ret = misc_register(&zf_miscdev); | |
444 | if (ret){ | |
445 | printk(KERN_ERR "can't misc_register on minor=%d\n", | |
446 | WATCHDOG_MINOR); | |
447 | goto out; | |
448 | } | |
449 | ||
450 | if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){ | |
451 | printk(KERN_ERR "cannot reserve I/O ports at %d\n", | |
452 | ZF_IOBASE); | |
453 | ret = -EBUSY; | |
454 | goto no_region; | |
455 | } | |
456 | ||
457 | ret = register_reboot_notifier(&zf_notifier); | |
458 | if(ret){ | |
459 | printk(KERN_ERR "can't register reboot notifier (err=%d)\n", | |
460 | ret); | |
461 | goto no_reboot; | |
462 | } | |
463 | ||
464 | zf_set_status(0); | |
465 | zf_set_control(0); | |
466 | ||
1da177e4 LT |
467 | return 0; |
468 | ||
469 | no_reboot: | |
470 | release_region(ZF_IOBASE, 3); | |
471 | no_region: | |
472 | misc_deregister(&zf_miscdev); | |
473 | out: | |
474 | return ret; | |
475 | } | |
476 | ||
477 | ||
478 | static void __exit zf_exit(void) | |
479 | { | |
480 | zf_timer_off(); | |
481 | ||
482 | misc_deregister(&zf_miscdev); | |
483 | unregister_reboot_notifier(&zf_notifier); | |
484 | release_region(ZF_IOBASE, 3); | |
485 | } | |
486 | ||
487 | module_init(zf_init); | |
488 | module_exit(zf_exit); |