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 unconditionally 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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
33 #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>
41 #include <linux/ioport.h>
42 #include <linux/notifier.h>
43 #include <linux/reboot.h>
44 #include <linux/init.h>
46 #include <linux/uaccess.h>
48 #include <asm/system.h>
51 #define ZF_IOBASE 0x218
57 /* indexes */ /* size */
58 #define ZFL_VERSION 0x02 /* 16 */
59 #define CONTROL 0x10 /* 16 */
60 #define STATUS 0x12 /* 8 */
61 #define COUNTER_1 0x0C /* 16 */
62 #define COUNTER_2 0x0E /* 8 */
63 #define PULSE_LEN 0x0F /* 8 */
66 #define ENABLE_WD1 0x0001
67 #define ENABLE_WD2 0x0002
68 #define RESET_WD1 0x0010
69 #define RESET_WD2 0x0020
70 #define GEN_SCI 0x0100
71 #define GEN_NMI 0x0200
72 #define GEN_SMI 0x0400
73 #define GEN_RESET 0x0800
81 #define zf_writew(port, data) { outb(port, INDEX); outw(data, DATA_W); }
82 #define zf_writeb(port, data) { outb(port, INDEX); outb(data, DATA_B); }
83 #define zf_get_ZFL_version() zf_readw(ZFL_VERSION)
86 static unsigned short zf_readw(unsigned char port)
93 MODULE_AUTHOR("Fernando Fuganti <fuganti@conectiva.com.br>");
94 MODULE_DESCRIPTION("MachZ ZF-Logic Watchdog driver");
95 MODULE_LICENSE("GPL");
96 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
98 static bool nowayout = WATCHDOG_NOWAYOUT;
99 module_param(nowayout, bool, 0);
100 MODULE_PARM_DESC(nowayout,
101 "Watchdog cannot be stopped once started (default="
102 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
104 #define PFX "machzwd"
106 static const struct watchdog_info zf_info = {
107 .options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
108 .firmware_version = 1,
109 .identity = "ZF-Logic watchdog",
114 * action refers to action taken when watchdog resets
119 * defaults to GEN_RESET (0)
122 module_param(action, int, 0);
123 MODULE_PARM_DESC(action, "after watchdog resets, generate: "
124 "0 = RESET(*) 1 = SMI 2 = NMI 3 = SCI");
126 static void zf_ping(unsigned long data);
128 static int zf_action = GEN_RESET;
129 static unsigned long zf_is_open;
130 static char zf_expect_close;
131 static DEFINE_SPINLOCK(zf_port_lock);
132 static DEFINE_TIMER(zf_timer, zf_ping, 0, 0);
133 static unsigned long next_heartbeat;
136 /* timeout for user land heart beat (10 seconds) */
137 #define ZF_USER_TIMEO (HZ*10)
139 /* timeout for hardware watchdog (~500ms) */
140 #define ZF_HW_TIMEO (HZ/2)
142 /* number of ticks on WD#1 (driven by a 32KHz clock, 2s) */
143 #define ZF_CTIMEOUT 0xffff
146 #define dprintk(format, args...)
148 #define dprintk(format, args...) \
149 pr_debug(":%s:%d: " format, __func__, __LINE__ , ## args)
153 static inline void zf_set_status(unsigned char new)
155 zf_writeb(STATUS, new);
159 /* CONTROL register functions */
161 static inline unsigned short zf_get_control(void)
163 return zf_readw(CONTROL);
166 static inline void zf_set_control(unsigned short new)
168 zf_writew(CONTROL, new);
172 /* WD#? counter functions */
174 * Just set counter value
177 static inline void zf_set_timer(unsigned short new, unsigned char n)
181 zf_writew(COUNTER_1, new);
183 zf_writeb(COUNTER_2, new > 0xff ? 0xff : new);
190 * stop hardware timer
192 static void zf_timer_off(void)
194 unsigned int ctrl_reg = 0;
197 /* stop internal ping */
198 del_timer_sync(&zf_timer);
200 spin_lock_irqsave(&zf_port_lock, flags);
201 /* stop watchdog timer */
202 ctrl_reg = zf_get_control();
203 ctrl_reg |= (ENABLE_WD1|ENABLE_WD2); /* disable wd1 and wd2 */
204 ctrl_reg &= ~(ENABLE_WD1|ENABLE_WD2);
205 zf_set_control(ctrl_reg);
206 spin_unlock_irqrestore(&zf_port_lock, flags);
208 pr_info("Watchdog timer is now disabled\n");
213 * start hardware timer
215 static void zf_timer_on(void)
217 unsigned int ctrl_reg = 0;
220 spin_lock_irqsave(&zf_port_lock, flags);
222 zf_writeb(PULSE_LEN, 0xff);
224 zf_set_timer(ZF_CTIMEOUT, WD1);
227 next_heartbeat = jiffies + ZF_USER_TIMEO;
229 /* start the timer for internal ping */
230 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
232 /* start watchdog timer */
233 ctrl_reg = zf_get_control();
234 ctrl_reg |= (ENABLE_WD1|zf_action);
235 zf_set_control(ctrl_reg);
236 spin_unlock_irqrestore(&zf_port_lock, flags);
238 pr_info("Watchdog timer is now enabled\n");
242 static void zf_ping(unsigned long data)
244 unsigned int ctrl_reg = 0;
247 zf_writeb(COUNTER_2, 0xff);
249 if (time_before(jiffies, next_heartbeat)) {
250 dprintk("time_before: %ld\n", next_heartbeat - jiffies);
252 * reset event is activated by transition from 0 to 1 on
253 * RESET_WD1 bit and we assume that it is already zero...
256 spin_lock_irqsave(&zf_port_lock, flags);
257 ctrl_reg = zf_get_control();
258 ctrl_reg |= RESET_WD1;
259 zf_set_control(ctrl_reg);
261 /* ...and nothing changes until here */
262 ctrl_reg &= ~(RESET_WD1);
263 zf_set_control(ctrl_reg);
264 spin_unlock_irqrestore(&zf_port_lock, flags);
266 mod_timer(&zf_timer, jiffies + ZF_HW_TIMEO);
268 pr_crit("I will reset your machine\n");
271 static ssize_t zf_write(struct file *file, const char __user *buf, size_t count,
274 /* See if we got the magic character */
277 * no need to check for close confirmation
278 * no way to disable watchdog ;)
283 * note: just in case someone wrote the magic character
289 for (ofs = 0; ofs != count; ofs++) {
291 if (get_user(c, buf + ofs))
294 zf_expect_close = 42;
295 dprintk("zf_expect_close = 42\n");
301 * Well, anyhow someone wrote to us,
302 * we should return that favour
304 next_heartbeat = jiffies + ZF_USER_TIMEO;
305 dprintk("user ping at %ld\n", jiffies);
310 static long zf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
312 void __user *argp = (void __user *)arg;
313 int __user *p = argp;
315 case WDIOC_GETSUPPORT:
316 if (copy_to_user(argp, &zf_info, sizeof(zf_info)))
319 case WDIOC_GETSTATUS:
320 case WDIOC_GETBOOTSTATUS:
321 return put_user(0, p);
322 case WDIOC_KEEPALIVE:
331 static int zf_open(struct inode *inode, struct file *file)
333 if (test_and_set_bit(0, &zf_is_open))
336 __module_get(THIS_MODULE);
338 return nonseekable_open(inode, file);
341 static int zf_close(struct inode *inode, struct file *file)
343 if (zf_expect_close == 42)
346 del_timer(&zf_timer);
347 pr_err("device file closed unexpectedly. Will not stop the WDT!\n");
349 clear_bit(0, &zf_is_open);
355 * Notifier for system down
358 static int zf_notify_sys(struct notifier_block *this, unsigned long code,
361 if (code == SYS_DOWN || code == SYS_HALT)
366 static const struct file_operations zf_fops = {
367 .owner = THIS_MODULE,
370 .unlocked_ioctl = zf_ioctl,
375 static struct miscdevice zf_miscdev = {
376 .minor = WATCHDOG_MINOR,
383 * The device needs to learn about soft shutdowns in order to
384 * turn the timebomb registers off.
386 static struct notifier_block zf_notifier = {
387 .notifier_call = zf_notify_sys,
390 static void __init zf_show_action(int act)
392 static const char * const str[] = { "RESET", "SMI", "NMI", "SCI" };
394 pr_info("Watchdog using action = %s\n", str[act]);
397 static int __init zf_init(void)
401 pr_info("MachZ ZF-Logic Watchdog driver initializing\n");
403 ret = zf_get_ZFL_version();
404 if (!ret || ret == 0xffff) {
405 pr_warn("no ZF-Logic found\n");
409 if (action <= 3 && action >= 0)
410 zf_action = zf_action >> action;
414 zf_show_action(action);
416 if (!request_region(ZF_IOBASE, 3, "MachZ ZFL WDT")) {
417 pr_err("cannot reserve I/O ports at %d\n", ZF_IOBASE);
422 ret = register_reboot_notifier(&zf_notifier);
424 pr_err("can't register reboot notifier (err=%d)\n", ret);
428 ret = misc_register(&zf_miscdev);
430 pr_err("can't misc_register on minor=%d\n", WATCHDOG_MINOR);
440 unregister_reboot_notifier(&zf_notifier);
442 release_region(ZF_IOBASE, 3);
448 static void __exit zf_exit(void)
452 misc_deregister(&zf_miscdev);
453 unregister_reboot_notifier(&zf_notifier);
454 release_region(ZF_IOBASE, 3);
457 module_init(zf_init);
458 module_exit(zf_exit);