1332b838cc5830f0be76fe104abdcf8c4e40cd93
[sfrench/cifs-2.6.git] / drivers / watchdog / machzwd.c
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 unconditionally 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 const 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         static const char * const 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);