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 #include <linux/io.h>
44 #include <linux/uaccess.h>
45
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,
99 "Watchdog cannot be stopped once started (default="
100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
101
102 #define PFX "machzwd"
103
104 static struct watchdog_info zf_info = {
105 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
106 .firmware_version = 1,
107 .identity = "ZF-Logic watchdog",
108 };
109
110
111 /*
112 * action refers to action taken when watchdog resets
113 * 0 = GEN_RESET
114 * 1 = GEN_SMI
115 * 2 = GEN_NMI
116 * 3 = GEN_SCI
117 * defaults to GEN_RESET (0)
118 */
119 static int action;
120 module_param(action, int, 0);
121 MODULE_PARM_DESC(action, "after watchdog resets, generate: "
122 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
123
124 static void zf_ping(unsigned long data);
125
126 static int zf_action = GEN_RESET;
127 static unsigned long zf_is_open;
128 static char zf_expect_close;
129 static DEFINE_SPINLOCK(zf_port_lock);
130 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
131 static unsigned long next_heartbeat;
132
133
134 /* timeout for user land heart beat (10 seconds) */
135 #define ZF_USER_TIMEO (HZ*10)
136
137 /* timeout for hardware watchdog (~500ms) */
138 #define ZF_HW_TIMEO (HZ/2)
139
140 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
141 #define ZF_CTIMEOUT 0xffff
142
143 #ifndef ZF_DEBUG
144 # define dprintk(format, args...)
145 #else
146 # define dprintk(format, args...) printk(KERN_DEBUG PFX
147 ":%s:%d: " format, __func__, __LINE__ , ## args)
148 #endif
149
150
151 static inline void zf_set_status(unsigned char new)
152 {
153 zf_writeb(STATUS, new);
154 }
155
156
157 /* CONTROL register functions */
158
159 static inline unsigned short zf_get_control(void)
160 {
161 return zf_readw(CONTROL);
162 }
163
164 static inline void zf_set_control(unsigned short new)
165 {
166 zf_writew(CONTROL, new);
167 }
168
169
170 /* WD#? counter functions */
171 /*
172 * Just set counter value
173 */
174
175 static inline void zf_set_timer(unsigned short new, unsigned char n)
176 {
177 switch (n) {
178 case WD1:
179 zf_writew(COUNTER_1, new);
180 case WD2:
181 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
182 default:
183 return;
184 }
185 }
186
187 /*
188 * stop hardware timer
189 */
190 static void zf_timer_off(void)
191 {
192 unsigned int ctrl_reg = 0;
193 unsigned long flags;
194
195 /* stop internal ping */
196 del_timer_sync(&zf_timer);
197
198 spin_lock_irqsave(&zf_port_lock, flags);
199 /* stop watchdog timer */
200 ctrl_reg = zf_get_control();
201 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
202 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
203 zf_set_control(ctrl_reg);
204 spin_unlock_irqrestore(&zf_port_lock, flags);
205
206 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
207 }
208
209
210 /*
211 * start hardware timer
212 */
213 static void zf_timer_on(void)
214 {
215 unsigned int ctrl_reg = 0;
216 unsigned long flags;
217
218 spin_lock_irqsave(&zf_port_lock, flags);
219
220 zf_writeb(PULSE_LEN, 0xff);
221
222 zf_set_timer(ZF_CTIMEOUT, WD1);
223
224 /* user land ping */
225 next_heartbeat = jiffies + ZF_USER_TIMEO;
226
227 /* start the timer for internal ping */
228 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
229
230 /* start watchdog timer */
231 ctrl_reg = zf_get_control();
232 ctrl_reg |= (ENABLE_WD1|zf_action);
233 zf_set_control(ctrl_reg);
234 spin_unlock_irqrestore(&zf_port_lock, flags);
235
236 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
237 }
238
239
240 static void zf_ping(unsigned long data)
241 {
242 unsigned int ctrl_reg = 0;
243 unsigned long flags;
244
245 zf_writeb(COUNTER_2, 0xff);
246
247 if (time_before(jiffies, next_heartbeat)) {
248 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
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 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
265 } else
266 printk(KERN_CRIT PFX ": I will reset your machine\n");
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 * no need to check for close confirmation
276 * no way to disable watchdog ;)
277 */
278 if (!nowayout) {
279 size_t ofs;
280 /*
281 * note: just in case someone wrote the magic character
282 * five months ago...
283 */
284 zf_expect_close = 0;
285
286 /* now scan */
287 for (ofs = 0; ofs != count; ofs++) {
288 char c;
289 if (get_user(c, buf + ofs))
290 return -EFAULT;
291 if (c == 'V') {
292 zf_expect_close = 42;
293 dprintk("zf_expect_close = 42\n");
294 }
295 }
296 }
297
298 /*
299 * Well, anyhow someone wrote to us,
300 * we should return that favour
301 */
302 next_heartbeat = jiffies + ZF_USER_TIMEO;
303 dprintk("user ping at %ld\n", jiffies);
304 }
305 return count;
306 }
307
308 static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
309 {
310 void __user *argp = (void __user *)arg;
311 int __user *p = argp;
312 switch (cmd) {
313 case WDIOC_GETSUPPORT:
314 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
315 return -EFAULT;
316 break;
317 case WDIOC_GETSTATUS:
318 case WDIOC_GETBOOTSTATUS:
319 return put_user(0, p);
320 case WDIOC_KEEPALIVE:
321 zf_ping(0);
322 break;
323 default:
324 return -ENOTTY;
325 }
326 return 0;
327 }
328
329 static int zf_open(struct inode *inode, struct file *file)
330 {
331 if (test_and_set_bit(0, &zf_is_open))
332 return -EBUSY;
333 if (nowayout)
334 __module_get(THIS_MODULE);
335 zf_timer_on();
336 return nonseekable_open(inode, file);
337 }
338
339 static int zf_close(struct inode *inode, struct file *file)
340 {
341 if (zf_expect_close == 42)
342 zf_timer_off();
343 else {
344 del_timer(&zf_timer);
345 printk(KERN_ERR PFX ": device file closed unexpectedly. "
346 "Will not stop the WDT!\n");
347 }
348 clear_bit(0, &zf_is_open);
349 zf_expect_close = 0;
350 return 0;
351 }
352
353 /*
354 * Notifier for system down
355 */
356
357 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
358 void *unused)
359 {
360 if (code == SYS_DOWN || code == SYS_HALT)
361 zf_timer_off();
362 return NOTIFY_DONE;
363 }
364
365 static const struct file_operations zf_fops = {
366 .owner = THIS_MODULE,
367 .llseek = no_llseek,
368 .write = zf_write,
369 .unlocked_ioctl = zf_ioctl,
370 .open = zf_open,
371 .release = zf_close,
372 };
373
374 static struct miscdevice zf_miscdev = {
375 .minor = WATCHDOG_MINOR,
376 .name = "watchdog",
377 .fops = &zf_fops,
378 };
379
380
381 /*
382 * The device needs to learn about soft shutdowns in order to
383 * turn the timebomb registers off.
384 */
385 static struct notifier_block zf_notifier = {
386 .notifier_call = zf_notify_sys,
387 };
388
389 static void __init zf_show_action(int act)
390 {
391 char *str[] = { "RESET", "SMI", "NMI", "SCI" };
392
393 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
394 }
395
396 static int __init zf_init(void)
397 {
398 int ret;
399
400 printk(KERN_INFO PFX
401 ": MachZ ZF-Logic Watchdog driver initializing.\n");
402
403 ret = zf_get_ZFL_version();
404 if (!ret || ret == 0xffff) {
405 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
406 return -ENODEV;
407 }
408
409 if (action <= 3 && action >= 0)
410 zf_action = zf_action >> action;
411 else
412 action = 0;
413
414 zf_show_action(action);
415
416 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
417 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
418 ZF_IOBASE);
419 ret = -EBUSY;
420 goto no_region;
421 }
422
423 ret = register_reboot_notifier(&zf_notifier);
424 if (ret) {
425 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
426 ret);
427 goto no_reboot;
428 }
429
430 ret = misc_register(&zf_miscdev);
431 if (ret) {
432 printk(KERN_ERR "can't misc_register on minor=%d\n",
433 WATCHDOG_MINOR);
434 goto no_misc;
435 }
436
437 zf_set_status(0);
438 zf_set_control(0);
439
440 return 0;
441
442 no_misc:
443 unregister_reboot_notifier(&zf_notifier);
444 no_reboot:
445 release_region(ZF_IOBASE, 3);
446 no_region:
447 return ret;
448 }
449
450
451 static void __exit zf_exit(void)
452 {
453 zf_timer_off();
454
455 misc_deregister(&zf_miscdev);
456 unregister_reboot_notifier(&zf_notifier);
457 release_region(ZF_IOBASE, 3);
458 }
459
460 module_init(zf_init);
461 module_exit(zf_exit);
462
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