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