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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 | ||
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 | static 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); |