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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
Joe Perches27c766a2012-02-15 15:06:19 -080031#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
32
Linus Torvalds1da177e2005-04-16 15:20:36 -070033#include <linux/module.h>
34#include <linux/moduleparam.h>
35#include <linux/types.h>
36#include <linux/timer.h>
37#include <linux/jiffies.h>
38#include <linux/miscdevice.h>
39#include <linux/watchdog.h>
40#include <linux/fs.h>
41#include <linux/ioport.h>
42#include <linux/notifier.h>
43#include <linux/reboot.h>
44#include <linux/init.h>
Alan Cox325ea4d2008-05-19 14:06:59 +010045#include <linux/io.h>
46#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
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 */
Wim Van Sebroeck5f3b2752011-02-23 20:04:38 +000058#define CONTROL 0x10 /* 16 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#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
85static unsigned short zf_readw(unsigned char port)
86{
87 outb(port, INDEX);
88 return inw(DATA_W);
89}
90
91
92MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
93MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
94MODULE_LICENSE("GPL");
95MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
96
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010097static bool nowayout = WATCHDOG_NOWAYOUT;
98module_param(nowayout, bool, 0);
Alan Cox325ea4d2008-05-19 14:06:59 +010099MODULE_PARM_DESC(nowayout,
100 "Watchdog cannot be stopped once started (default="
101 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102
103#define PFX "machzwd"
104
Wim Van Sebroeck42747d72009-12-26 18:55:22 +0000105static const struct watchdog_info zf_info = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
107 .firmware_version = 1,
108 .identity = "ZF-Logic watchdog",
109};
110
111
112/*
113 * action refers to action taken when watchdog resets
114 * 0 = GEN_RESET
115 * 1 = GEN_SMI
116 * 2 = GEN_NMI
117 * 3 = GEN_SCI
118 * defaults to GEN_RESET (0)
119 */
Alan Cox325ea4d2008-05-19 14:06:59 +0100120static int action;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121module_param(action, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +0000122MODULE_PARM_DESC(action, "after watchdog resets, generate: "
123 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100125static void zf_ping(unsigned long data);
126
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127static int zf_action = GEN_RESET;
128static unsigned long zf_is_open;
129static char zf_expect_close;
Alexey Dobriyanc7dfd0c2007-11-01 16:27:08 -0700130static DEFINE_SPINLOCK(zf_port_lock);
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100131static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
Alan Cox325ea4d2008-05-19 14:06:59 +0100132static unsigned long next_heartbeat;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
134
135/* timeout for user land heart beat (10 seconds) */
136#define ZF_USER_TIMEO (HZ*10)
137
138/* timeout for hardware watchdog (~500ms) */
139#define ZF_HW_TIMEO (HZ/2)
140
141/* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
142#define ZF_CTIMEOUT 0xffff
143
144#ifndef ZF_DEBUG
Joe Perches27c766a2012-02-15 15:06:19 -0800145#define dprintk(format, args...)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146#else
Joe Perches27c766a2012-02-15 15:06:19 -0800147#define dprintk(format, args...) \
148 pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149#endif
150
151
152static inline void zf_set_status(unsigned char new)
153{
154 zf_writeb(STATUS, new);
155}
156
157
158/* CONTROL register functions */
159
160static inline unsigned short zf_get_control(void)
161{
162 return zf_readw(CONTROL);
163}
164
165static 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
176static inline void zf_set_timer(unsigned short new, unsigned char n)
177{
Alan Cox325ea4d2008-05-19 14:06:59 +0100178 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 }
186}
187
188/*
189 * stop hardware timer
190 */
191static 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
Joe Perches27c766a2012-02-15 15:06:19 -0800207 pr_info("Watchdog timer is now disabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208}
209
210
211/*
212 * start hardware timer
213 */
214static 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 */
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100229 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230
231 /* start watchdog timer */
232 ctrl_reg = zf_get_control();
233 ctrl_reg |= (ENABLE_WD1|zf_action);
234 zf_set_control(ctrl_reg);
235 spin_unlock_irqrestore(&zf_port_lock, flags);
236
Joe Perches27c766a2012-02-15 15:06:19 -0800237 pr_info("Watchdog timer is now enabled\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238}
239
240
241static void zf_ping(unsigned long data)
242{
243 unsigned int ctrl_reg = 0;
244 unsigned long flags;
245
246 zf_writeb(COUNTER_2, 0xff);
247
Alan Cox325ea4d2008-05-19 14:06:59 +0100248 if (time_before(jiffies, next_heartbeat)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 /*
251 * reset event is activated by transition from 0 to 1 on
252 * RESET_WD1 bit and we assume that it is already zero...
253 */
254
255 spin_lock_irqsave(&zf_port_lock, flags);
256 ctrl_reg = zf_get_control();
257 ctrl_reg |= RESET_WD1;
258 zf_set_control(ctrl_reg);
259
260 /* ...and nothing changes until here */
261 ctrl_reg &= ~(RESET_WD1);
262 zf_set_control(ctrl_reg);
263 spin_unlock_irqrestore(&zf_port_lock, flags);
264
Jiri Slaby82eb7c52007-02-08 18:39:36 +0100265 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
Alan Cox325ea4d2008-05-19 14:06:59 +0100266 } else
Joe Perches27c766a2012-02-15 15:06:19 -0800267 pr_crit("I will reset your machine\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268}
269
270static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
271 loff_t *ppos)
272{
273 /* See if we got the magic character */
Alan Cox325ea4d2008-05-19 14:06:59 +0100274 if (count) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 /*
276 * no need to check for close confirmation
277 * no way to disable watchdog ;)
278 */
279 if (!nowayout) {
280 size_t ofs;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 /*
282 * note: just in case someone wrote the magic character
283 * five months ago...
284 */
285 zf_expect_close = 0;
286
287 /* now scan */
Alan Cox325ea4d2008-05-19 14:06:59 +0100288 for (ofs = 0; ofs != count; ofs++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 char c;
290 if (get_user(c, buf + ofs))
291 return -EFAULT;
Alan Cox325ea4d2008-05-19 14:06:59 +0100292 if (c == 'V') {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 zf_expect_close = 42;
294 dprintk("zf_expect_close = 42\n");
295 }
296 }
297 }
298
299 /*
300 * Well, anyhow someone wrote to us,
301 * we should return that favour
302 */
303 next_heartbeat = jiffies + ZF_USER_TIMEO;
304 dprintk("user ping at %ld\n", jiffies);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306 return count;
307}
308
Alan Cox325ea4d2008-05-19 14:06:59 +0100309static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310{
311 void __user *argp = (void __user *)arg;
312 int __user *p = argp;
Andrew Mortonbad77052007-03-18 01:26:10 -0800313 switch (cmd) {
314 case WDIOC_GETSUPPORT:
315 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
316 return -EFAULT;
317 break;
Andrew Mortonbad77052007-03-18 01:26:10 -0800318 case WDIOC_GETSTATUS:
Wim Van Sebroeck5c4eb612007-07-21 13:42:18 +0000319 case WDIOC_GETBOOTSTATUS:
Andrew Mortonbad77052007-03-18 01:26:10 -0800320 return put_user(0, p);
Andrew Mortonbad77052007-03-18 01:26:10 -0800321 case WDIOC_KEEPALIVE:
322 zf_ping(0);
323 break;
Andrew Mortonbad77052007-03-18 01:26:10 -0800324 default:
325 return -ENOTTY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 return 0;
328}
329
330static int zf_open(struct inode *inode, struct file *file)
331{
Alan Cox325ea4d2008-05-19 14:06:59 +0100332 if (test_and_set_bit(0, &zf_is_open))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 return -EBUSY;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 if (nowayout)
335 __module_get(THIS_MODULE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 zf_timer_on();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 return nonseekable_open(inode, file);
338}
339
340static int zf_close(struct inode *inode, struct file *file)
341{
Alan Cox325ea4d2008-05-19 14:06:59 +0100342 if (zf_expect_close == 42)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700343 zf_timer_off();
Alan Cox325ea4d2008-05-19 14:06:59 +0100344 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 del_timer(&zf_timer);
Joe Perches27c766a2012-02-15 15:06:19 -0800346 pr_err("device file closed unexpectedly. 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{
Joe Perchesa2b89cd2010-09-13 21:23:59 -0700391 static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392
Joe Perches27c766a2012-02-15 15:06:19 -0800393 pr_info("Watchdog using action = %s\n", str[act]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394}
395
396static int __init zf_init(void)
397{
398 int ret;
399
Joe Perches27c766a2012-02-15 15:06:19 -0800400 pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401
402 ret = zf_get_ZFL_version();
Alan Cox325ea4d2008-05-19 14:06:59 +0100403 if (!ret || ret == 0xffff) {
Joe Perches27c766a2012-02-15 15:06:19 -0800404 pr_warn("no ZF-Logic found\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 return -ENODEV;
406 }
407
Alan Cox325ea4d2008-05-19 14:06:59 +0100408 if (action <= 3 && action >= 0)
409 zf_action = zf_action >> action;
410 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 action = 0;
412
413 zf_show_action(action);
414
Alan Cox325ea4d2008-05-19 14:06:59 +0100415 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
Joe Perches27c766a2012-02-15 15:06:19 -0800416 pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417 ret = -EBUSY;
418 goto no_region;
419 }
420
421 ret = register_reboot_notifier(&zf_notifier);
Alan Cox325ea4d2008-05-19 14:06:59 +0100422 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800423 pr_err("can't register reboot notifier (err=%d)\n", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 goto no_reboot;
425 }
426
Alexey Dobriyanfb8f7ba2007-03-24 15:58:12 +0300427 ret = misc_register(&zf_miscdev);
Alan Cox325ea4d2008-05-19 14:06:59 +0100428 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800429 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
Alexey Dobriyanfb8f7ba2007-03-24 15:58:12 +0300430 goto no_misc;
431 }
432
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 zf_set_status(0);
434 zf_set_control(0);
435
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436 return 0;
437
Alexey Dobriyanfb8f7ba2007-03-24 15:58:12 +0300438no_misc:
439 unregister_reboot_notifier(&zf_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440no_reboot:
441 release_region(ZF_IOBASE, 3);
442no_region:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 return ret;
444}
445
446
447static void __exit zf_exit(void)
448{
449 zf_timer_off();
450
451 misc_deregister(&zf_miscdev);
452 unregister_reboot_notifier(&zf_notifier);
453 release_region(ZF_IOBASE, 3);
454}
455
456module_init(zf_init);
457module_exit(zf_exit);