2 * MachZ ZF-Logic Watchdog Timer driver for Linux
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.
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.
14 * Author: Fernando Fuganti <fuganti@conectiva.com.br>
16 * Based on sbc60xxwdt.c by Jakob Oestergaard
19 * We have two timers (wd#1, wd#2) driven by a 32 KHz clock with the
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.
27 * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
28 * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
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>
40 #include <linux/ioport.h>
41 #include <linux/notifier.h>
42 #include <linux/reboot.h>
43 #include <linux/init.h>
46 #include <asm/uaccess.h>
47 #include <asm/system.h>
50 #define ZF_IOBASE 0x218
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 */
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
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)
85 static unsigned short zf_readw(unsigned char port)
91 static unsigned short zf_readb(unsigned char port)
98 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
99 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
100 MODULE_LICENSE("GPL");
101 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
103 #ifdef CONFIG_WATCHDOG_NOWAYOUT
104 static int nowayout = 1;
106 static int nowayout = 0;
109 module_param(nowayout, int, 0);
110 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)");
112 #define PFX "machzwd"
114 static struct watchdog_info zf_info = {
115 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
116 .firmware_version = 1,
117 .identity = "ZF-Logic watchdog",
122 * action refers to action taken when watchdog resets
127 * defaults to GEN_RESET (0)
129 static int action = 0;
130 module_param(action, int, 0);
131 MODULE_PARM_DESC(action, "after watchdog resets, generate: 0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
133 static int zf_action = GEN_RESET;
134 static unsigned long zf_is_open;
135 static char zf_expect_close;
136 static spinlock_t zf_lock;
137 static spinlock_t zf_port_lock;
138 static struct timer_list zf_timer;
139 static unsigned long next_heartbeat = 0;
142 /* timeout for user land heart beat (10 seconds) */
143 #define ZF_USER_TIMEO (HZ*10)
145 /* timeout for hardware watchdog (~500ms) */
146 #define ZF_HW_TIMEO (HZ/2)
148 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
149 #define ZF_CTIMEOUT 0xffff
152 # define dprintk(format, args...)
154 # define dprintk(format, args...) printk(KERN_DEBUG PFX ":%s:%d: " format, __FUNCTION__, __LINE__ , ## args)
158 /* STATUS register functions */
160 static inline unsigned char zf_get_status(void)
162 return zf_readb(STATUS);
165 static inline void zf_set_status(unsigned char new)
167 zf_writeb(STATUS, new);
171 /* CONTROL register functions */
173 static inline unsigned short zf_get_control(void)
175 return zf_readw(CONTROL);
178 static inline void zf_set_control(unsigned short new)
180 zf_writew(CONTROL, new);
184 /* WD#? counter functions */
186 * Just get current counter value
189 static inline unsigned short zf_get_timer(unsigned char n)
193 return zf_readw(COUNTER_1);
195 return zf_readb(COUNTER_2);
202 * Just set counter value
205 static inline void zf_set_timer(unsigned short new, unsigned char n)
209 zf_writew(COUNTER_1, new);
211 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
218 * stop hardware timer
220 static void zf_timer_off(void)
222 unsigned int ctrl_reg = 0;
225 /* stop internal ping */
226 del_timer_sync(&zf_timer);
228 spin_lock_irqsave(&zf_port_lock, flags);
229 /* stop watchdog timer */
230 ctrl_reg = zf_get_control();
231 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
232 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
233 zf_set_control(ctrl_reg);
234 spin_unlock_irqrestore(&zf_port_lock, flags);
236 printk(KERN_INFO PFX ": Watchdog timer is now disabled\n");
241 * start hardware timer
243 static void zf_timer_on(void)
245 unsigned int ctrl_reg = 0;
248 spin_lock_irqsave(&zf_port_lock, flags);
250 zf_writeb(PULSE_LEN, 0xff);
252 zf_set_timer(ZF_CTIMEOUT, WD1);
255 next_heartbeat = jiffies + ZF_USER_TIMEO;
257 /* start the timer for internal ping */
258 zf_timer.expires = jiffies + ZF_HW_TIMEO;
260 add_timer(&zf_timer);
262 /* start watchdog timer */
263 ctrl_reg = zf_get_control();
264 ctrl_reg |= (ENABLE_WD1|zf_action);
265 zf_set_control(ctrl_reg);
266 spin_unlock_irqrestore(&zf_port_lock, flags);
268 printk(KERN_INFO PFX ": Watchdog timer is now enabled\n");
272 static void zf_ping(unsigned long data)
274 unsigned int ctrl_reg = 0;
277 zf_writeb(COUNTER_2, 0xff);
279 if(time_before(jiffies, next_heartbeat)){
281 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
284 * reset event is activated by transition from 0 to 1 on
285 * RESET_WD1 bit and we assume that it is already zero...
288 spin_lock_irqsave(&zf_port_lock, flags);
289 ctrl_reg = zf_get_control();
290 ctrl_reg |= RESET_WD1;
291 zf_set_control(ctrl_reg);
293 /* ...and nothing changes until here */
294 ctrl_reg &= ~(RESET_WD1);
295 zf_set_control(ctrl_reg);
296 spin_unlock_irqrestore(&zf_port_lock, flags);
298 zf_timer.expires = jiffies + ZF_HW_TIMEO;
299 add_timer(&zf_timer);
301 printk(KERN_CRIT PFX ": I will reset your machine\n");
305 static ssize_t zf_write(struct file *file, const char *buf, size_t count,
308 /* Can't seek (pwrite) on this device */
309 if (ppos != &file->f_pos)
312 /* See if we got the magic character */
316 * no need to check for close confirmation
317 * no way to disable watchdog ;)
323 * note: just in case someone wrote the magic character
329 for (ofs = 0; ofs != count; ofs++){
331 if (get_user(c, buf + ofs))
334 zf_expect_close = 42;
335 dprintk("zf_expect_close = 42\n");
341 * Well, anyhow someone wrote to us,
342 * we should return that favour
344 next_heartbeat = jiffies + ZF_USER_TIMEO;
345 dprintk("user ping at %ld\n", jiffies);
352 static int zf_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
356 case WDIOC_GETSUPPORT:
357 if (copy_to_user((struct watchdog_info *)arg,
358 &zf_info, sizeof(zf_info)))
362 case WDIOC_GETSTATUS:
363 return put_user(0, (int *) arg);
365 case WDIOC_KEEPALIVE:
376 static int zf_open(struct inode *inode, struct file *file)
379 if(test_and_set_bit(0, &zf_is_open)) {
380 spin_unlock(&zf_lock);
385 __module_get(THIS_MODULE);
387 spin_unlock(&zf_lock);
394 static int zf_close(struct inode *inode, struct file *file)
396 if(zf_expect_close == 42){
399 del_timer(&zf_timer);
400 printk(KERN_ERR PFX ": device file closed unexpectedly. Will not stop the WDT!\n");
404 clear_bit(0, &zf_is_open);
405 spin_unlock(&zf_lock);
413 * Notifier for system down
416 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
419 if(code == SYS_DOWN || code == SYS_HALT){
429 static struct file_operations zf_fops = {
430 .owner = THIS_MODULE,
437 static struct miscdevice zf_miscdev = {
438 .minor = WATCHDOG_MINOR,
445 * The device needs to learn about soft shutdowns in order to
446 * turn the timebomb registers off.
448 static struct notifier_block zf_notifier = {
449 .notifier_call = zf_notify_sys,
452 static void __init zf_show_action(int act)
454 char *str[] = { "RESET", "SMI", "NMI", "SCI" };
456 printk(KERN_INFO PFX ": Watchdog using action = %s\n", str[act]);
459 static int __init zf_init(void)
463 printk(KERN_INFO PFX ": MachZ ZF-Logic Watchdog driver initializing.\n");
465 ret = zf_get_ZFL_version();
466 printk("%#x\n", ret);
467 if((!ret) || (ret != 0xffff)){
468 printk(KERN_WARNING PFX ": no ZF-Logic found\n");
472 if((action <= 3) && (action >= 0)){
473 zf_action = zf_action>>action;
477 zf_show_action(action);
479 spin_lock_init(&zf_lock);
480 spin_lock_init(&zf_port_lock);
482 ret = misc_register(&zf_miscdev);
484 printk(KERN_ERR "can't misc_register on minor=%d\n",
489 if(!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")){
490 printk(KERN_ERR "cannot reserve I/O ports at %d\n",
496 ret = register_reboot_notifier(&zf_notifier);
498 printk(KERN_ERR "can't register reboot notifier (err=%d)\n",
506 /* this is the timer that will do the hard work */
507 init_timer(&zf_timer);
508 zf_timer.function = zf_ping;
514 release_region(ZF_IOBASE, 3);
516 misc_deregister(&zf_miscdev);
522 void __exit zf_exit(void)
526 misc_deregister(&zf_miscdev);
527 unregister_reboot_notifier(&zf_notifier);
528 release_region(ZF_IOBASE, 3);
531 module_init(zf_init);
532 module_exit(zf_exit);