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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
André Goddard Rosaaf901ca2009-11-14 13:09:05 -020024 * a system RESET and it starts wd#2 that unconditionally will RESET
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070031#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>
Alan Cox325ea4d2008-05-19 14:06:59 +010043#include <linux/io.h>
44#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070045
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#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
84static unsigned short zf_readw(unsigned char port)
85{
86 outb(port, INDEX);
87 return inw(DATA_W);
88}
89
90
91MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
92MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
93MODULE_LICENSE("GPL");
94MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
95
Andrey Panin4bfdf372005-07-27 11:43:58 -070096static int nowayout = WATCHDOG_NOWAYOUT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097module_param(nowayout, int, 0);
Alan Cox325ea4d2008-05-19 14:06:59 +010098MODULE_PARM_DESC(nowayout,
99 "Watchdog cannot be stopped once started (default="
100 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
102#define PFX "machzwd"
103
104static 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 */
Alan Cox325ea4d2008-05-19 14:06:59 +0100119static int action;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120module_param(action, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000121MODULE_PARM_DESC(action, "after watchdog resets, generate: "
122 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100124static void zf_ping(unsigned long data);
125
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126static int zf_action = GEN_RESET;
127static unsigned long zf_is_open;
128static char zf_expect_close;
Alexey Dobriyanc7dfd0c2007-11-01 16:27:08 -0700129static DEFINE_SPINLOCK(zf_port_lock);
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100130static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
Alan Cox325ea4d2008-05-19 14:06:59 +0100131static unsigned long next_heartbeat;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132
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
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000146# define dprintk(format, args...) printk(KERN_DEBUG PFX
147 ":%s:%d: " format, __func__, __LINE__ , ## args)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148#endif
149
150
151static inline void zf_set_status(unsigned char new)
152{
153 zf_writeb(STATUS, new);
154}
155
156
157/* CONTROL register functions */
158
159static inline unsigned short zf_get_control(void)
160{
161 return zf_readw(CONTROL);
162}
163
164static 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
175static inline void zf_set_timer(unsigned short new, unsigned char n)
176{
Alan Cox325ea4d2008-05-19 14:06:59 +0100177 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184 }
185}
186
187/*
188 * stop hardware timer
189 */
190static 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 */
213static 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 */
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100228 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229
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
240static 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
Alan Cox325ea4d2008-05-19 14:06:59 +0100247 if (time_before(jiffies, next_heartbeat)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 /*
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
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100264 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
Alan Cox325ea4d2008-05-19 14:06:59 +0100265 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 printk(KERN_CRIT PFX ": I will reset your machine\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267}
268
269static 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 */
Alan Cox325ea4d2008-05-19 14:06:59 +0100273 if (count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 /*
275 * no need to check for close confirmation
276 * no way to disable watchdog ;)
277 */
278 if (!nowayout) {
279 size_t ofs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 /*
281 * note: just in case someone wrote the magic character
282 * five months ago...
283 */
284 zf_expect_close = 0;
285
286 /* now scan */
Alan Cox325ea4d2008-05-19 14:06:59 +0100287 for (ofs = 0; ofs != count; ofs++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288 char c;
289 if (get_user(c, buf + ofs))
290 return -EFAULT;
Alan Cox325ea4d2008-05-19 14:06:59 +0100291 if (c == 'V') {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 return count;
306}
307
Alan Cox325ea4d2008-05-19 14:06:59 +0100308static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309{
310 void __user *argp = (void __user *)arg;
311 int __user *p = argp;
Andrew Mortonbad77052007-03-18 01:26:10 -0800312 switch (cmd) {
313 case WDIOC_GETSUPPORT:
314 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
315 return -EFAULT;
316 break;
Andrew Mortonbad77052007-03-18 01:26:10 -0800317 case WDIOC_GETSTATUS:
Wim Van Sebroeck5c4eb612007-07-21 13:42:18 +0000318 case WDIOC_GETBOOTSTATUS:
Andrew Mortonbad77052007-03-18 01:26:10 -0800319 return put_user(0, p);
Andrew Mortonbad77052007-03-18 01:26:10 -0800320 case WDIOC_KEEPALIVE:
321 zf_ping(0);
322 break;
Andrew Mortonbad77052007-03-18 01:26:10 -0800323 default:
324 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 return 0;
327}
328
329static int zf_open(struct inode *inode, struct file *file)
330{
Alan Cox325ea4d2008-05-19 14:06:59 +0100331 if (test_and_set_bit(0, &zf_is_open))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 if (nowayout)
334 __module_get(THIS_MODULE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 zf_timer_on();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 return nonseekable_open(inode, file);
337}
338
339static int zf_close(struct inode *inode, struct file *file)
340{
Alan Cox325ea4d2008-05-19 14:06:59 +0100341 if (zf_expect_close == 42)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 zf_timer_off();
Alan Cox325ea4d2008-05-19 14:06:59 +0100343 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 del_timer(&zf_timer);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000345 printk(KERN_ERR PFX ": device file closed unexpectedly. "
346 "Will not stop the WDT!\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 clear_bit(0, &zf_is_open);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 zf_expect_close = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 return 0;
351}
352
353/*
354 * Notifier for system down
355 */
356
357static int zf_notify_sys(struct notifier_block *this, unsigned long code,
358 void *unused)
359{
Alan Cox325ea4d2008-05-19 14:06:59 +0100360 if (code == SYS_DOWN || code == SYS_HALT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 zf_timer_off();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362 return NOTIFY_DONE;
363}
364
Arjan van de Ven62322d22006-07-03 00:24:21 -0700365static const struct file_operations zf_fops = {
Alan Cox325ea4d2008-05-19 14:06:59 +0100366 .owner = THIS_MODULE,
367 .llseek = no_llseek,
368 .write = zf_write,
369 .unlocked_ioctl = zf_ioctl,
370 .open = zf_open,
371 .release = zf_close,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372};
373
374static struct miscdevice zf_miscdev = {
375 .minor = WATCHDOG_MINOR,
376 .name = "watchdog",
377 .fops = &zf_fops,
378};
Alan Cox325ea4d2008-05-19 14:06:59 +0100379
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380
381/*
382 * The device needs to learn about soft shutdowns in order to
383 * turn the timebomb registers off.
384 */
385static struct notifier_block zf_notifier = {
386 .notifier_call = zf_notify_sys,
387};
388
389static 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
396static int __init zf_init(void)
397{
398 int ret;
399
Alan Cox325ea4d2008-05-19 14:06:59 +0100400 printk(KERN_INFO PFX
401 ": MachZ ZF-Logic Watchdog driver initializing.\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402
403 ret = zf_get_ZFL_version();
Alan Cox325ea4d2008-05-19 14:06:59 +0100404 if (!ret || ret == 0xffff) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
406 return -ENODEV;
407 }
408
Alan Cox325ea4d2008-05-19 14:06:59 +0100409 if (action <= 3 && action >= 0)
410 zf_action = zf_action >> action;
411 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 action = 0;
413
414 zf_show_action(action);
415
Alan Cox325ea4d2008-05-19 14:06:59 +0100416 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 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);
Alan Cox325ea4d2008-05-19 14:06:59 +0100424 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
426 ret);
427 goto no_reboot;
428 }
429
Alexey Dobriyanfb8f7ba2007-03-24 15:58:12 +0300430 ret = misc_register(&zf_miscdev);
Alan Cox325ea4d2008-05-19 14:06:59 +0100431 if (ret) {
Alexey Dobriyanfb8f7ba2007-03-24 15:58:12 +0300432 printk(KERN_ERR "can't misc_register on minor=%d\n",
433 WATCHDOG_MINOR);
434 goto no_misc;
435 }
436
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 zf_set_status(0);
438 zf_set_control(0);
439
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 return 0;
441
Alexey Dobriyanfb8f7ba2007-03-24 15:58:12 +0300442no_misc:
443 unregister_reboot_notifier(&zf_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444no_reboot:
445 release_region(ZF_IOBASE, 3);
446no_region:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 return ret;
448}
449
450
451static 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
460module_init(zf_init);
461module_exit(zf_exit);