2 * IT8712F "Smart Guardian" Watchdog support
4 * Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
6 * Based on info and code taken from:
8 * drivers/char/watchdog/scx200_wdt.c
10 * IT8712F EC-LPC I/O Preliminary Specification 0.8.2
11 * IT8712F EC-LPC I/O Preliminary Specification 0.9.3
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License as
15 * published by the Free Software Foundation; either version 2 of the
16 * License, or (at your option) any later version.
18 * The author(s) of this software shall not be held liable for damages
19 * of any nature resulting due to the use of this software. This
20 * software is provided AS-IS with no warranties.
23 #include <linux/module.h>
24 #include <linux/moduleparam.h>
25 #include <linux/init.h>
26 #include <linux/miscdevice.h>
27 #include <linux/watchdog.h>
28 #include <linux/notifier.h>
29 #include <linux/reboot.h>
31 #include <linux/spinlock.h>
32 #include <linux/uaccess.h>
34 #include <linux/ioport.h>
36 #define NAME "it8712f_wdt"
38 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
39 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
40 MODULE_LICENSE("GPL");
41 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
43 static int max_units = 255;
44 static int margin = 60; /* in seconds */
45 module_param(margin, int, 0);
46 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
48 static int nowayout = WATCHDOG_NOWAYOUT;
49 module_param(nowayout, int, 0);
50 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
52 static unsigned long wdt_open;
53 static unsigned expect_close;
54 static unsigned char revision;
56 /* Dog Food address - We use the game port address */
57 static unsigned short address;
59 #define REG 0x2e /* The register to read/write */
60 #define VAL 0x2f /* The value to read/write */
62 #define LDN 0x07 /* Register: Logical device select */
63 #define DEVID 0x20 /* Register: Device ID */
64 #define DEVREV 0x22 /* Register: Device Revision */
65 #define ACT_REG 0x30 /* LDN Register: Activation */
66 #define BASE_REG 0x60 /* LDN Register: Base address */
68 #define IT8712F_DEVID 0x8712
70 #define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
71 #define LDN_GAME 0x09 /* Game Port */
73 #define WDT_CONTROL 0x71 /* WDT Register: Control */
74 #define WDT_CONFIG 0x72 /* WDT Register: Configuration */
75 #define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */
77 #define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */
78 #define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */
79 #define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */
80 #define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */
82 #define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */
84 #define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */
85 #define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */
87 static int wdt_control_reg = WDT_RESET_GAME;
88 module_param(wdt_control_reg, int, 0);
89 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
90 "register. The default WDT_RESET_GAME resets the timer on "
91 "game port reads that this driver generates. You can also "
92 "use KBD, MOUSE or CIR if you have some external way to "
93 "generate those interrupts.");
95 static int superio_inb(int reg)
101 static void superio_outb(int val, int reg)
107 static int superio_inw(int reg)
117 static inline void superio_select(int ldn)
123 static inline int superio_enter(void)
126 * Try to reserve REG and REG + 1 for exclusive access.
128 if (!request_muxed_region(REG, 2, NAME))
138 static inline void superio_exit(void)
142 release_region(REG, 2);
145 static inline void it8712f_wdt_ping(void)
147 if (wdt_control_reg & WDT_RESET_GAME)
151 static void it8712f_wdt_update_margin(void)
153 int config = WDT_OUT_KRST | WDT_OUT_PWROK;
156 /* Switch to minutes precision if the configured margin
157 * value does not fit within the register width.
159 if (units <= max_units) {
160 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
161 printk(KERN_INFO NAME ": timer margin %d seconds\n", units);
164 printk(KERN_INFO NAME ": timer margin %d minutes\n", units);
166 superio_outb(config, WDT_CONFIG);
168 if (revision >= 0x08)
169 superio_outb(units >> 8, WDT_TIMEOUT + 1);
170 superio_outb(units, WDT_TIMEOUT);
173 static int it8712f_wdt_get_status(void)
175 if (superio_inb(WDT_CONTROL) & 0x01)
176 return WDIOF_CARDRESET;
181 static int it8712f_wdt_enable(void)
183 int ret = superio_enter();
187 printk(KERN_DEBUG NAME ": enabling watchdog timer\n");
188 superio_select(LDN_GPIO);
190 superio_outb(wdt_control_reg, WDT_CONTROL);
192 it8712f_wdt_update_margin();
201 static int it8712f_wdt_disable(void)
203 int ret = superio_enter();
207 printk(KERN_DEBUG NAME ": disabling watchdog timer\n");
208 superio_select(LDN_GPIO);
210 superio_outb(0, WDT_CONFIG);
211 superio_outb(0, WDT_CONTROL);
212 if (revision >= 0x08)
213 superio_outb(0, WDT_TIMEOUT + 1);
214 superio_outb(0, WDT_TIMEOUT);
220 static int it8712f_wdt_notify(struct notifier_block *this,
221 unsigned long code, void *unused)
223 if (code == SYS_HALT || code == SYS_POWER_OFF)
225 it8712f_wdt_disable();
230 static struct notifier_block it8712f_wdt_notifier = {
231 .notifier_call = it8712f_wdt_notify,
234 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
235 size_t len, loff_t *ppos)
237 /* check for a magic close character */
244 for (i = 0; i < len; ++i) {
246 if (get_user(c, data + i))
256 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
259 void __user *argp = (void __user *)arg;
260 int __user *p = argp;
261 static const struct watchdog_info ident = {
262 .identity = "IT8712F Watchdog",
263 .firmware_version = 1,
264 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
271 case WDIOC_GETSUPPORT:
272 if (copy_to_user(argp, &ident, sizeof(ident)))
275 case WDIOC_GETSTATUS:
276 ret = superio_enter();
279 superio_select(LDN_GPIO);
281 value = it8712f_wdt_get_status();
285 return put_user(value, p);
286 case WDIOC_GETBOOTSTATUS:
287 return put_user(0, p);
288 case WDIOC_KEEPALIVE:
291 case WDIOC_SETTIMEOUT:
292 if (get_user(value, p))
296 if (value > (max_units * 60))
299 ret = superio_enter();
302 superio_select(LDN_GPIO);
304 it8712f_wdt_update_margin();
309 case WDIOC_GETTIMEOUT:
310 if (put_user(margin, p))
318 static int it8712f_wdt_open(struct inode *inode, struct file *file)
321 /* only allow one at a time */
322 if (test_and_set_bit(0, &wdt_open))
325 ret = it8712f_wdt_enable();
328 return nonseekable_open(inode, file);
331 static int it8712f_wdt_release(struct inode *inode, struct file *file)
333 if (expect_close != 42) {
334 printk(KERN_WARNING NAME
335 ": watchdog device closed unexpectedly, will not"
336 " disable the watchdog timer\n");
337 } else if (!nowayout) {
338 if (it8712f_wdt_disable())
339 printk(KERN_WARNING NAME "Watchdog disable failed\n");
342 clear_bit(0, &wdt_open);
347 static const struct file_operations it8712f_wdt_fops = {
348 .owner = THIS_MODULE,
350 .write = it8712f_wdt_write,
351 .unlocked_ioctl = it8712f_wdt_ioctl,
352 .open = it8712f_wdt_open,
353 .release = it8712f_wdt_release,
356 static struct miscdevice it8712f_wdt_miscdev = {
357 .minor = WATCHDOG_MINOR,
359 .fops = &it8712f_wdt_fops,
362 static int __init it8712f_wdt_find(unsigned short *address)
366 int ret = superio_enter();
370 chip_type = superio_inw(DEVID);
371 if (chip_type != IT8712F_DEVID)
374 superio_select(LDN_GAME);
375 superio_outb(1, ACT_REG);
376 if (!(superio_inb(ACT_REG) & 0x01)) {
377 printk(KERN_ERR NAME ": Device not activated, skipping\n");
381 *address = superio_inw(BASE_REG);
383 printk(KERN_ERR NAME ": Base address not set, skipping\n");
388 revision = superio_inb(DEVREV) & 0x0f;
390 /* Later revisions have 16-bit values per datasheet 0.9.1 */
391 if (revision >= 0x08)
394 if (margin > (max_units * 60))
395 margin = (max_units * 60);
397 printk(KERN_INFO NAME ": Found IT%04xF chip revision %d - "
398 "using DogFood address 0x%x\n",
399 chip_type, revision, *address);
406 static int __init it8712f_wdt_init(void)
410 if (it8712f_wdt_find(&address))
413 if (!request_region(address, 1, "IT8712F Watchdog")) {
414 printk(KERN_WARNING NAME ": watchdog I/O region busy\n");
418 err = it8712f_wdt_disable();
420 printk(KERN_ERR NAME ": unable to disable watchdog timer.\n");
424 err = register_reboot_notifier(&it8712f_wdt_notifier);
426 printk(KERN_ERR NAME ": unable to register reboot notifier\n");
430 err = misc_register(&it8712f_wdt_miscdev);
433 ": cannot register miscdev on minor=%d (err=%d)\n",
434 WATCHDOG_MINOR, err);
442 unregister_reboot_notifier(&it8712f_wdt_notifier);
444 release_region(address, 1);
448 static void __exit it8712f_wdt_exit(void)
450 misc_deregister(&it8712f_wdt_miscdev);
451 unregister_reboot_notifier(&it8712f_wdt_notifier);
452 release_region(address, 1);
455 module_init(it8712f_wdt_init);
456 module_exit(it8712f_wdt_exit);