1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * IT8712F "Smart Guardian" Watchdog support
5 * Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
7 * Based on info and code taken from:
9 * drivers/char/watchdog/scx200_wdt.c
10 * drivers/hwmon/it87.c
11 * IT8712F EC-LPC I/O Preliminary Specification 0.8.2
12 * IT8712F EC-LPC I/O Preliminary Specification 0.9.3
14 * The author(s) of this software shall not be held liable for damages
15 * of any nature resulting due to the use of this software. This
16 * software is provided AS-IS with no warranties.
19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 #include <linux/module.h>
22 #include <linux/moduleparam.h>
23 #include <linux/init.h>
24 #include <linux/miscdevice.h>
25 #include <linux/watchdog.h>
26 #include <linux/notifier.h>
27 #include <linux/reboot.h>
29 #include <linux/spinlock.h>
30 #include <linux/uaccess.h>
32 #include <linux/ioport.h>
34 #define NAME "it8712f_wdt"
36 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
37 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
38 MODULE_LICENSE("GPL");
40 static int max_units = 255;
41 static int margin = 60; /* in seconds */
42 module_param(margin, int, 0);
43 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
45 static bool nowayout = WATCHDOG_NOWAYOUT;
46 module_param(nowayout, bool, 0);
47 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
49 static unsigned long wdt_open;
50 static unsigned expect_close;
51 static unsigned char revision;
53 /* Dog Food address - We use the game port address */
54 static unsigned short address;
56 #define REG 0x2e /* The register to read/write */
57 #define VAL 0x2f /* The value to read/write */
59 #define LDN 0x07 /* Register: Logical device select */
60 #define DEVID 0x20 /* Register: Device ID */
61 #define DEVREV 0x22 /* Register: Device Revision */
62 #define ACT_REG 0x30 /* LDN Register: Activation */
63 #define BASE_REG 0x60 /* LDN Register: Base address */
65 #define IT8712F_DEVID 0x8712
67 #define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */
68 #define LDN_GAME 0x09 /* Game Port */
70 #define WDT_CONTROL 0x71 /* WDT Register: Control */
71 #define WDT_CONFIG 0x72 /* WDT Register: Configuration */
72 #define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */
74 #define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */
75 #define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */
76 #define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */
77 #define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */
79 #define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */
81 #define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */
82 #define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */
84 static int wdt_control_reg = WDT_RESET_GAME;
85 module_param(wdt_control_reg, int, 0);
86 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
87 "register. The default WDT_RESET_GAME resets the timer on "
88 "game port reads that this driver generates. You can also "
89 "use KBD, MOUSE or CIR if you have some external way to "
90 "generate those interrupts.");
92 static int superio_inb(int reg)
98 static void superio_outb(int val, int reg)
104 static int superio_inw(int reg)
114 static inline void superio_select(int ldn)
120 static inline int superio_enter(void)
123 * Try to reserve REG and REG + 1 for exclusive access.
125 if (!request_muxed_region(REG, 2, NAME))
135 static inline void superio_exit(void)
139 release_region(REG, 2);
142 static inline void it8712f_wdt_ping(void)
144 if (wdt_control_reg & WDT_RESET_GAME)
148 static void it8712f_wdt_update_margin(void)
150 int config = WDT_OUT_KRST | WDT_OUT_PWROK;
153 /* Switch to minutes precision if the configured margin
154 * value does not fit within the register width.
156 if (units <= max_units) {
157 config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
158 pr_info("timer margin %d seconds\n", units);
161 pr_info("timer margin %d minutes\n", units);
163 superio_outb(config, WDT_CONFIG);
165 if (revision >= 0x08)
166 superio_outb(units >> 8, WDT_TIMEOUT + 1);
167 superio_outb(units, WDT_TIMEOUT);
170 static int it8712f_wdt_get_status(void)
172 if (superio_inb(WDT_CONTROL) & 0x01)
173 return WDIOF_CARDRESET;
178 static int it8712f_wdt_enable(void)
180 int ret = superio_enter();
184 pr_debug("enabling watchdog timer\n");
185 superio_select(LDN_GPIO);
187 superio_outb(wdt_control_reg, WDT_CONTROL);
189 it8712f_wdt_update_margin();
198 static int it8712f_wdt_disable(void)
200 int ret = superio_enter();
204 pr_debug("disabling watchdog timer\n");
205 superio_select(LDN_GPIO);
207 superio_outb(0, WDT_CONFIG);
208 superio_outb(0, WDT_CONTROL);
209 if (revision >= 0x08)
210 superio_outb(0, WDT_TIMEOUT + 1);
211 superio_outb(0, WDT_TIMEOUT);
217 static int it8712f_wdt_notify(struct notifier_block *this,
218 unsigned long code, void *unused)
220 if (code == SYS_HALT || code == SYS_POWER_OFF)
222 it8712f_wdt_disable();
227 static struct notifier_block it8712f_wdt_notifier = {
228 .notifier_call = it8712f_wdt_notify,
231 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
232 size_t len, loff_t *ppos)
234 /* check for a magic close character */
241 for (i = 0; i < len; ++i) {
243 if (get_user(c, data + i))
253 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
256 void __user *argp = (void __user *)arg;
257 int __user *p = argp;
258 static const struct watchdog_info ident = {
259 .identity = "IT8712F Watchdog",
260 .firmware_version = 1,
261 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
268 case WDIOC_GETSUPPORT:
269 if (copy_to_user(argp, &ident, sizeof(ident)))
272 case WDIOC_GETSTATUS:
273 ret = superio_enter();
276 superio_select(LDN_GPIO);
278 value = it8712f_wdt_get_status();
282 return put_user(value, p);
283 case WDIOC_GETBOOTSTATUS:
284 return put_user(0, p);
285 case WDIOC_KEEPALIVE:
288 case WDIOC_SETTIMEOUT:
289 if (get_user(value, p))
293 if (value > (max_units * 60))
296 ret = superio_enter();
299 superio_select(LDN_GPIO);
301 it8712f_wdt_update_margin();
306 case WDIOC_GETTIMEOUT:
307 if (put_user(margin, p))
315 static int it8712f_wdt_open(struct inode *inode, struct file *file)
318 /* only allow one at a time */
319 if (test_and_set_bit(0, &wdt_open))
322 ret = it8712f_wdt_enable();
325 return stream_open(inode, file);
328 static int it8712f_wdt_release(struct inode *inode, struct file *file)
330 if (expect_close != 42) {
331 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
332 } else if (!nowayout) {
333 if (it8712f_wdt_disable())
334 pr_warn("Watchdog disable failed\n");
337 clear_bit(0, &wdt_open);
342 static const struct file_operations it8712f_wdt_fops = {
343 .owner = THIS_MODULE,
345 .write = it8712f_wdt_write,
346 .unlocked_ioctl = it8712f_wdt_ioctl,
347 .compat_ioctl = compat_ptr_ioctl,
348 .open = it8712f_wdt_open,
349 .release = it8712f_wdt_release,
352 static struct miscdevice it8712f_wdt_miscdev = {
353 .minor = WATCHDOG_MINOR,
355 .fops = &it8712f_wdt_fops,
358 static int __init it8712f_wdt_find(unsigned short *address)
362 int ret = superio_enter();
366 chip_type = superio_inw(DEVID);
367 if (chip_type != IT8712F_DEVID)
370 superio_select(LDN_GAME);
371 superio_outb(1, ACT_REG);
372 if (!(superio_inb(ACT_REG) & 0x01)) {
373 pr_err("Device not activated, skipping\n");
377 *address = superio_inw(BASE_REG);
379 pr_err("Base address not set, skipping\n");
384 revision = superio_inb(DEVREV) & 0x0f;
386 /* Later revisions have 16-bit values per datasheet 0.9.1 */
387 if (revision >= 0x08)
390 if (margin > (max_units * 60))
391 margin = (max_units * 60);
393 pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
394 chip_type, revision, *address);
401 static int __init it8712f_wdt_init(void)
405 if (it8712f_wdt_find(&address))
408 if (!request_region(address, 1, "IT8712F Watchdog")) {
409 pr_warn("watchdog I/O region busy\n");
413 err = it8712f_wdt_disable();
415 pr_err("unable to disable watchdog timer\n");
419 err = register_reboot_notifier(&it8712f_wdt_notifier);
421 pr_err("unable to register reboot notifier\n");
425 err = misc_register(&it8712f_wdt_miscdev);
427 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
428 WATCHDOG_MINOR, err);
436 unregister_reboot_notifier(&it8712f_wdt_notifier);
438 release_region(address, 1);
442 static void __exit it8712f_wdt_exit(void)
444 misc_deregister(&it8712f_wdt_miscdev);
445 unregister_reboot_notifier(&it8712f_wdt_notifier);
446 release_region(address, 1);
449 module_init(it8712f_wdt_init);
450 module_exit(it8712f_wdt_exit);