xref: /linux/drivers/watchdog/it8712f_wdt.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732) 
1 /*
2  *	IT8712F "Smart Guardian" Watchdog support
3  *
4  *	Copyright (c) 2006-2007 Jorge Boncompte - DTI2 <jorge@dti2.net>
5  *
6  *	Based on info and code taken from:
7  *
8  *	drivers/char/watchdog/scx200_wdt.c
9  *	drivers/hwmon/it87.c
10  *	IT8712F EC-LPC I/O Preliminary Specification 0.8.2
11  *	IT8712F EC-LPC I/O Preliminary Specification 0.9.3
12  *
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.
17  *
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.
21  */
22 
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/module.h>
26 #include <linux/moduleparam.h>
27 #include <linux/init.h>
28 #include <linux/miscdevice.h>
29 #include <linux/watchdog.h>
30 #include <linux/notifier.h>
31 #include <linux/reboot.h>
32 #include <linux/fs.h>
33 #include <linux/spinlock.h>
34 #include <linux/uaccess.h>
35 #include <linux/io.h>
36 #include <linux/ioport.h>
37 
38 #define DEBUG
39 #define NAME "it8712f_wdt"
40 
41 MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
42 MODULE_DESCRIPTION("IT8712F Watchdog Driver");
43 MODULE_LICENSE("GPL");
44 
45 static int max_units = 255;
46 static int margin = 60;		/* in seconds */
47 module_param(margin, int, 0);
48 MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
49 
50 static bool nowayout = WATCHDOG_NOWAYOUT;
51 module_param(nowayout, bool, 0);
52 MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
53 
54 static unsigned long wdt_open;
55 static unsigned expect_close;
56 static unsigned char revision;
57 
58 /* Dog Food address - We use the game port address */
59 static unsigned short address;
60 
61 #define	REG		0x2e	/* The register to read/write */
62 #define	VAL		0x2f	/* The value to read/write */
63 
64 #define	LDN		0x07	/* Register: Logical device select */
65 #define	DEVID		0x20	/* Register: Device ID */
66 #define	DEVREV		0x22	/* Register: Device Revision */
67 #define ACT_REG		0x30	/* LDN Register: Activation */
68 #define BASE_REG	0x60	/* LDN Register: Base address */
69 
70 #define IT8712F_DEVID	0x8712
71 
72 #define LDN_GPIO	0x07	/* GPIO and Watch Dog Timer */
73 #define LDN_GAME	0x09	/* Game Port */
74 
75 #define WDT_CONTROL	0x71	/* WDT Register: Control */
76 #define WDT_CONFIG	0x72	/* WDT Register: Configuration */
77 #define WDT_TIMEOUT	0x73	/* WDT Register: Timeout Value */
78 
79 #define WDT_RESET_GAME	0x10	/* Reset timer on read or write to game port */
80 #define WDT_RESET_KBD	0x20	/* Reset timer on keyboard interrupt */
81 #define WDT_RESET_MOUSE	0x40	/* Reset timer on mouse interrupt */
82 #define WDT_RESET_CIR	0x80	/* Reset timer on consumer IR interrupt */
83 
84 #define WDT_UNIT_SEC	0x80	/* If 0 in MINUTES */
85 
86 #define WDT_OUT_PWROK	0x10	/* Pulse PWROK on timeout */
87 #define WDT_OUT_KRST	0x40	/* Pulse reset on timeout */
88 
89 static int wdt_control_reg = WDT_RESET_GAME;
90 module_param(wdt_control_reg, int, 0);
91 MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
92 		"register. The default WDT_RESET_GAME resets the timer on "
93 		"game port reads that this driver generates. You can also "
94 		"use KBD, MOUSE or CIR if you have some external way to "
95 		"generate those interrupts.");
96 
97 static int superio_inb(int reg)
98 {
99 	outb(reg, REG);
100 	return inb(VAL);
101 }
102 
103 static void superio_outb(int val, int reg)
104 {
105 	outb(reg, REG);
106 	outb(val, VAL);
107 }
108 
109 static int superio_inw(int reg)
110 {
111 	int val;
112 	outb(reg++, REG);
113 	val = inb(VAL) << 8;
114 	outb(reg, REG);
115 	val |= inb(VAL);
116 	return val;
117 }
118 
119 static inline void superio_select(int ldn)
120 {
121 	outb(LDN, REG);
122 	outb(ldn, VAL);
123 }
124 
125 static inline int superio_enter(void)
126 {
127 	/*
128 	 * Try to reserve REG and REG + 1 for exclusive access.
129 	 */
130 	if (!request_muxed_region(REG, 2, NAME))
131 		return -EBUSY;
132 
133 	outb(0x87, REG);
134 	outb(0x01, REG);
135 	outb(0x55, REG);
136 	outb(0x55, REG);
137 	return 0;
138 }
139 
140 static inline void superio_exit(void)
141 {
142 	outb(0x02, REG);
143 	outb(0x02, VAL);
144 	release_region(REG, 2);
145 }
146 
147 static inline void it8712f_wdt_ping(void)
148 {
149 	if (wdt_control_reg & WDT_RESET_GAME)
150 		inb(address);
151 }
152 
153 static void it8712f_wdt_update_margin(void)
154 {
155 	int config = WDT_OUT_KRST | WDT_OUT_PWROK;
156 	int units = margin;
157 
158 	/* Switch to minutes precision if the configured margin
159 	 * value does not fit within the register width.
160 	 */
161 	if (units <= max_units) {
162 		config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */
163 		pr_info("timer margin %d seconds\n", units);
164 	} else {
165 		units /= 60;
166 		pr_info("timer margin %d minutes\n", units);
167 	}
168 	superio_outb(config, WDT_CONFIG);
169 
170 	if (revision >= 0x08)
171 		superio_outb(units >> 8, WDT_TIMEOUT + 1);
172 	superio_outb(units, WDT_TIMEOUT);
173 }
174 
175 static int it8712f_wdt_get_status(void)
176 {
177 	if (superio_inb(WDT_CONTROL) & 0x01)
178 		return WDIOF_CARDRESET;
179 	else
180 		return 0;
181 }
182 
183 static int it8712f_wdt_enable(void)
184 {
185 	int ret = superio_enter();
186 	if (ret)
187 		return ret;
188 
189 	pr_debug("enabling watchdog timer\n");
190 	superio_select(LDN_GPIO);
191 
192 	superio_outb(wdt_control_reg, WDT_CONTROL);
193 
194 	it8712f_wdt_update_margin();
195 
196 	superio_exit();
197 
198 	it8712f_wdt_ping();
199 
200 	return 0;
201 }
202 
203 static int it8712f_wdt_disable(void)
204 {
205 	int ret = superio_enter();
206 	if (ret)
207 		return ret;
208 
209 	pr_debug("disabling watchdog timer\n");
210 	superio_select(LDN_GPIO);
211 
212 	superio_outb(0, WDT_CONFIG);
213 	superio_outb(0, WDT_CONTROL);
214 	if (revision >= 0x08)
215 		superio_outb(0, WDT_TIMEOUT + 1);
216 	superio_outb(0, WDT_TIMEOUT);
217 
218 	superio_exit();
219 	return 0;
220 }
221 
222 static int it8712f_wdt_notify(struct notifier_block *this,
223 		    unsigned long code, void *unused)
224 {
225 	if (code == SYS_HALT || code == SYS_POWER_OFF)
226 		if (!nowayout)
227 			it8712f_wdt_disable();
228 
229 	return NOTIFY_DONE;
230 }
231 
232 static struct notifier_block it8712f_wdt_notifier = {
233 	.notifier_call = it8712f_wdt_notify,
234 };
235 
236 static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
237 					size_t len, loff_t *ppos)
238 {
239 	/* check for a magic close character */
240 	if (len) {
241 		size_t i;
242 
243 		it8712f_wdt_ping();
244 
245 		expect_close = 0;
246 		for (i = 0; i < len; ++i) {
247 			char c;
248 			if (get_user(c, data + i))
249 				return -EFAULT;
250 			if (c == 'V')
251 				expect_close = 42;
252 		}
253 	}
254 
255 	return len;
256 }
257 
258 static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
259 							unsigned long arg)
260 {
261 	void __user *argp = (void __user *)arg;
262 	int __user *p = argp;
263 	static const struct watchdog_info ident = {
264 		.identity = "IT8712F Watchdog",
265 		.firmware_version = 1,
266 		.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
267 						WDIOF_MAGICCLOSE,
268 	};
269 	int value;
270 	int ret;
271 
272 	switch (cmd) {
273 	case WDIOC_GETSUPPORT:
274 		if (copy_to_user(argp, &ident, sizeof(ident)))
275 			return -EFAULT;
276 		return 0;
277 	case WDIOC_GETSTATUS:
278 		ret = superio_enter();
279 		if (ret)
280 			return ret;
281 		superio_select(LDN_GPIO);
282 
283 		value = it8712f_wdt_get_status();
284 
285 		superio_exit();
286 
287 		return put_user(value, p);
288 	case WDIOC_GETBOOTSTATUS:
289 		return put_user(0, p);
290 	case WDIOC_KEEPALIVE:
291 		it8712f_wdt_ping();
292 		return 0;
293 	case WDIOC_SETTIMEOUT:
294 		if (get_user(value, p))
295 			return -EFAULT;
296 		if (value < 1)
297 			return -EINVAL;
298 		if (value > (max_units * 60))
299 			return -EINVAL;
300 		margin = value;
301 		ret = superio_enter();
302 		if (ret)
303 			return ret;
304 		superio_select(LDN_GPIO);
305 
306 		it8712f_wdt_update_margin();
307 
308 		superio_exit();
309 		it8712f_wdt_ping();
310 		/* Fall through */
311 	case WDIOC_GETTIMEOUT:
312 		if (put_user(margin, p))
313 			return -EFAULT;
314 		return 0;
315 	default:
316 		return -ENOTTY;
317 	}
318 }
319 
320 static int it8712f_wdt_open(struct inode *inode, struct file *file)
321 {
322 	int ret;
323 	/* only allow one at a time */
324 	if (test_and_set_bit(0, &wdt_open))
325 		return -EBUSY;
326 
327 	ret = it8712f_wdt_enable();
328 	if (ret)
329 		return ret;
330 	return nonseekable_open(inode, file);
331 }
332 
333 static int it8712f_wdt_release(struct inode *inode, struct file *file)
334 {
335 	if (expect_close != 42) {
336 		pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
337 	} else if (!nowayout) {
338 		if (it8712f_wdt_disable())
339 			pr_warn("Watchdog disable failed\n");
340 	}
341 	expect_close = 0;
342 	clear_bit(0, &wdt_open);
343 
344 	return 0;
345 }
346 
347 static const struct file_operations it8712f_wdt_fops = {
348 	.owner = THIS_MODULE,
349 	.llseek = no_llseek,
350 	.write = it8712f_wdt_write,
351 	.unlocked_ioctl = it8712f_wdt_ioctl,
352 	.open = it8712f_wdt_open,
353 	.release = it8712f_wdt_release,
354 };
355 
356 static struct miscdevice it8712f_wdt_miscdev = {
357 	.minor = WATCHDOG_MINOR,
358 	.name = "watchdog",
359 	.fops = &it8712f_wdt_fops,
360 };
361 
362 static int __init it8712f_wdt_find(unsigned short *address)
363 {
364 	int err = -ENODEV;
365 	int chip_type;
366 	int ret = superio_enter();
367 	if (ret)
368 		return ret;
369 
370 	chip_type = superio_inw(DEVID);
371 	if (chip_type != IT8712F_DEVID)
372 		goto exit;
373 
374 	superio_select(LDN_GAME);
375 	superio_outb(1, ACT_REG);
376 	if (!(superio_inb(ACT_REG) & 0x01)) {
377 		pr_err("Device not activated, skipping\n");
378 		goto exit;
379 	}
380 
381 	*address = superio_inw(BASE_REG);
382 	if (*address == 0) {
383 		pr_err("Base address not set, skipping\n");
384 		goto exit;
385 	}
386 
387 	err = 0;
388 	revision = superio_inb(DEVREV) & 0x0f;
389 
390 	/* Later revisions have 16-bit values per datasheet 0.9.1 */
391 	if (revision >= 0x08)
392 		max_units = 65535;
393 
394 	if (margin > (max_units * 60))
395 		margin = (max_units * 60);
396 
397 	pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
398 		chip_type, revision, *address);
399 
400 exit:
401 	superio_exit();
402 	return err;
403 }
404 
405 static int __init it8712f_wdt_init(void)
406 {
407 	int err = 0;
408 
409 	if (it8712f_wdt_find(&address))
410 		return -ENODEV;
411 
412 	if (!request_region(address, 1, "IT8712F Watchdog")) {
413 		pr_warn("watchdog I/O region busy\n");
414 		return -EBUSY;
415 	}
416 
417 	err = it8712f_wdt_disable();
418 	if (err) {
419 		pr_err("unable to disable watchdog timer\n");
420 		goto out;
421 	}
422 
423 	err = register_reboot_notifier(&it8712f_wdt_notifier);
424 	if (err) {
425 		pr_err("unable to register reboot notifier\n");
426 		goto out;
427 	}
428 
429 	err = misc_register(&it8712f_wdt_miscdev);
430 	if (err) {
431 		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
432 		       WATCHDOG_MINOR, err);
433 		goto reboot_out;
434 	}
435 
436 	return 0;
437 
438 
439 reboot_out:
440 	unregister_reboot_notifier(&it8712f_wdt_notifier);
441 out:
442 	release_region(address, 1);
443 	return err;
444 }
445 
446 static void __exit it8712f_wdt_exit(void)
447 {
448 	misc_deregister(&it8712f_wdt_miscdev);
449 	unregister_reboot_notifier(&it8712f_wdt_notifier);
450 	release_region(address, 1);
451 }
452 
453 module_init(it8712f_wdt_init);
454 module_exit(it8712f_wdt_exit);
455