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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 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
45 | |
46 | static int max_units = 255; |
47 | static int margin = 60; /* in seconds */ |
48 | module_param(margin, int, 0); |
49 | MODULE_PARM_DESC(margin, "Watchdog margin in seconds"); |
50 | |
51 | static bool nowayout = WATCHDOG_NOWAYOUT; |
52 | module_param(nowayout, bool, 0); |
53 | MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close"); |
54 | |
55 | static unsigned long wdt_open; |
56 | static unsigned expect_close; |
57 | static unsigned char revision; |
58 | |
59 | /* Dog Food address - We use the game port address */ |
60 | static unsigned short address; |
61 | |
62 | #define REG 0x2e /* The register to read/write */ |
63 | #define VAL 0x2f /* The value to read/write */ |
64 | |
65 | #define LDN 0x07 /* Register: Logical device select */ |
66 | #define DEVID 0x20 /* Register: Device ID */ |
67 | #define DEVREV 0x22 /* Register: Device Revision */ |
68 | #define ACT_REG 0x30 /* LDN Register: Activation */ |
69 | #define BASE_REG 0x60 /* LDN Register: Base address */ |
70 | |
71 | #define IT8712F_DEVID 0x8712 |
72 | |
73 | #define LDN_GPIO 0x07 /* GPIO and Watch Dog Timer */ |
74 | #define LDN_GAME 0x09 /* Game Port */ |
75 | |
76 | #define WDT_CONTROL 0x71 /* WDT Register: Control */ |
77 | #define WDT_CONFIG 0x72 /* WDT Register: Configuration */ |
78 | #define WDT_TIMEOUT 0x73 /* WDT Register: Timeout Value */ |
79 | |
80 | #define WDT_RESET_GAME 0x10 /* Reset timer on read or write to game port */ |
81 | #define WDT_RESET_KBD 0x20 /* Reset timer on keyboard interrupt */ |
82 | #define WDT_RESET_MOUSE 0x40 /* Reset timer on mouse interrupt */ |
83 | #define WDT_RESET_CIR 0x80 /* Reset timer on consumer IR interrupt */ |
84 | |
85 | #define WDT_UNIT_SEC 0x80 /* If 0 in MINUTES */ |
86 | |
87 | #define WDT_OUT_PWROK 0x10 /* Pulse PWROK on timeout */ |
88 | #define WDT_OUT_KRST 0x40 /* Pulse reset on timeout */ |
89 | |
90 | static int wdt_control_reg = WDT_RESET_GAME; |
91 | module_param(wdt_control_reg, int, 0); |
92 | MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control " |
93 | "register. The default WDT_RESET_GAME resets the timer on " |
94 | "game port reads that this driver generates. You can also " |
95 | "use KBD, MOUSE or CIR if you have some external way to " |
96 | "generate those interrupts."); |
97 | |
98 | static int superio_inb(int reg) |
99 | { |
100 | outb(reg, REG); |
101 | return inb(VAL); |
102 | } |
103 | |
104 | static void superio_outb(int val, int reg) |
105 | { |
106 | outb(reg, REG); |
107 | outb(val, VAL); |
108 | } |
109 | |
110 | static int superio_inw(int reg) |
111 | { |
112 | int val; |
113 | outb(reg++, REG); |
114 | val = inb(VAL) << 8; |
115 | outb(reg, REG); |
116 | val |= inb(VAL); |
117 | return val; |
118 | } |
119 | |
120 | static inline void superio_select(int ldn) |
121 | { |
122 | outb(LDN, REG); |
123 | outb(ldn, VAL); |
124 | } |
125 | |
126 | static inline int superio_enter(void) |
127 | { |
128 | /* |
129 | * Try to reserve REG and REG + 1 for exclusive access. |
130 | */ |
131 | if (!request_muxed_region(REG, 2, NAME)) |
132 | return -EBUSY; |
133 | |
134 | outb(0x87, REG); |
135 | outb(0x01, REG); |
136 | outb(0x55, REG); |
137 | outb(0x55, REG); |
138 | return 0; |
139 | } |
140 | |
141 | static inline void superio_exit(void) |
142 | { |
143 | outb(0x02, REG); |
144 | outb(0x02, VAL); |
145 | release_region(REG, 2); |
146 | } |
147 | |
148 | static inline void it8712f_wdt_ping(void) |
149 | { |
150 | if (wdt_control_reg & WDT_RESET_GAME) |
151 | inb(address); |
152 | } |
153 | |
154 | static void it8712f_wdt_update_margin(void) |
155 | { |
156 | int config = WDT_OUT_KRST | WDT_OUT_PWROK; |
157 | int units = margin; |
158 | |
159 | /* Switch to minutes precision if the configured margin |
160 | * value does not fit within the register width. |
161 | */ |
162 | if (units <= max_units) { |
163 | config |= WDT_UNIT_SEC; /* else UNIT is MINUTES */ |
164 | pr_info("timer margin %d seconds\n", units); |
165 | } else { |
166 | units /= 60; |
167 | pr_info("timer margin %d minutes\n", units); |
168 | } |
169 | superio_outb(config, WDT_CONFIG); |
170 | |
171 | if (revision >= 0x08) |
172 | superio_outb(units >> 8, WDT_TIMEOUT + 1); |
173 | superio_outb(units, WDT_TIMEOUT); |
174 | } |
175 | |
176 | static int it8712f_wdt_get_status(void) |
177 | { |
178 | if (superio_inb(WDT_CONTROL) & 0x01) |
179 | return WDIOF_CARDRESET; |
180 | else |
181 | return 0; |
182 | } |
183 | |
184 | static int it8712f_wdt_enable(void) |
185 | { |
186 | int ret = superio_enter(); |
187 | if (ret) |
188 | return ret; |
189 | |
190 | pr_debug("enabling watchdog timer\n"); |
191 | superio_select(LDN_GPIO); |
192 | |
193 | superio_outb(wdt_control_reg, WDT_CONTROL); |
194 | |
195 | it8712f_wdt_update_margin(); |
196 | |
197 | superio_exit(); |
198 | |
199 | it8712f_wdt_ping(); |
200 | |
201 | return 0; |
202 | } |
203 | |
204 | static int it8712f_wdt_disable(void) |
205 | { |
206 | int ret = superio_enter(); |
207 | if (ret) |
208 | return ret; |
209 | |
210 | pr_debug("disabling watchdog timer\n"); |
211 | superio_select(LDN_GPIO); |
212 | |
213 | superio_outb(0, WDT_CONFIG); |
214 | superio_outb(0, WDT_CONTROL); |
215 | if (revision >= 0x08) |
216 | superio_outb(0, WDT_TIMEOUT + 1); |
217 | superio_outb(0, WDT_TIMEOUT); |
218 | |
219 | superio_exit(); |
220 | return 0; |
221 | } |
222 | |
223 | static int it8712f_wdt_notify(struct notifier_block *this, |
224 | unsigned long code, void *unused) |
225 | { |
226 | if (code == SYS_HALT || code == SYS_POWER_OFF) |
227 | if (!nowayout) |
228 | it8712f_wdt_disable(); |
229 | |
230 | return NOTIFY_DONE; |
231 | } |
232 | |
233 | static struct notifier_block it8712f_wdt_notifier = { |
234 | .notifier_call = it8712f_wdt_notify, |
235 | }; |
236 | |
237 | static ssize_t it8712f_wdt_write(struct file *file, const char __user *data, |
238 | size_t len, loff_t *ppos) |
239 | { |
240 | /* check for a magic close character */ |
241 | if (len) { |
242 | size_t i; |
243 | |
244 | it8712f_wdt_ping(); |
245 | |
246 | expect_close = 0; |
247 | for (i = 0; i < len; ++i) { |
248 | char c; |
249 | if (get_user(c, data + i)) |
250 | return -EFAULT; |
251 | if (c == 'V') |
252 | expect_close = 42; |
253 | } |
254 | } |
255 | |
256 | return len; |
257 | } |
258 | |
259 | static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd, |
260 | unsigned long arg) |
261 | { |
262 | void __user *argp = (void __user *)arg; |
263 | int __user *p = argp; |
264 | static const struct watchdog_info ident = { |
265 | .identity = "IT8712F Watchdog", |
266 | .firmware_version = 1, |
267 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
268 | WDIOF_MAGICCLOSE, |
269 | }; |
270 | int value; |
271 | int ret; |
272 | |
273 | switch (cmd) { |
274 | case WDIOC_GETSUPPORT: |
275 | if (copy_to_user(argp, &ident, sizeof(ident))) |
276 | return -EFAULT; |
277 | return 0; |
278 | case WDIOC_GETSTATUS: |
279 | ret = superio_enter(); |
280 | if (ret) |
281 | return ret; |
282 | superio_select(LDN_GPIO); |
283 | |
284 | value = it8712f_wdt_get_status(); |
285 | |
286 | superio_exit(); |
287 | |
288 | return put_user(value, p); |
289 | case WDIOC_GETBOOTSTATUS: |
290 | return put_user(0, p); |
291 | case WDIOC_KEEPALIVE: |
292 | it8712f_wdt_ping(); |
293 | return 0; |
294 | case WDIOC_SETTIMEOUT: |
295 | if (get_user(value, p)) |
296 | return -EFAULT; |
297 | if (value < 1) |
298 | return -EINVAL; |
299 | if (value > (max_units * 60)) |
300 | return -EINVAL; |
301 | margin = value; |
302 | ret = superio_enter(); |
303 | if (ret) |
304 | return ret; |
305 | superio_select(LDN_GPIO); |
306 | |
307 | it8712f_wdt_update_margin(); |
308 | |
309 | superio_exit(); |
310 | it8712f_wdt_ping(); |
311 | /* Fall through */ |
312 | case WDIOC_GETTIMEOUT: |
313 | if (put_user(margin, p)) |
314 | return -EFAULT; |
315 | return 0; |
316 | default: |
317 | return -ENOTTY; |
318 | } |
319 | } |
320 | |
321 | static int it8712f_wdt_open(struct inode *inode, struct file *file) |
322 | { |
323 | int ret; |
324 | /* only allow one at a time */ |
325 | if (test_and_set_bit(0, &wdt_open)) |
326 | return -EBUSY; |
327 | |
328 | ret = it8712f_wdt_enable(); |
329 | if (ret) |
330 | return ret; |
331 | return nonseekable_open(inode, file); |
332 | } |
333 | |
334 | static int it8712f_wdt_release(struct inode *inode, struct file *file) |
335 | { |
336 | if (expect_close != 42) { |
337 | pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n"); |
338 | } else if (!nowayout) { |
339 | if (it8712f_wdt_disable()) |
340 | pr_warn("Watchdog disable failed\n"); |
341 | } |
342 | expect_close = 0; |
343 | clear_bit(0, &wdt_open); |
344 | |
345 | return 0; |
346 | } |
347 | |
348 | static const struct file_operations it8712f_wdt_fops = { |
349 | .owner = THIS_MODULE, |
350 | .llseek = no_llseek, |
351 | .write = it8712f_wdt_write, |
352 | .unlocked_ioctl = it8712f_wdt_ioctl, |
353 | .open = it8712f_wdt_open, |
354 | .release = it8712f_wdt_release, |
355 | }; |
356 | |
357 | static struct miscdevice it8712f_wdt_miscdev = { |
358 | .minor = WATCHDOG_MINOR, |
359 | .name = "watchdog", |
360 | .fops = &it8712f_wdt_fops, |
361 | }; |
362 | |
363 | static int __init it8712f_wdt_find(unsigned short *address) |
364 | { |
365 | int err = -ENODEV; |
366 | int chip_type; |
367 | int ret = superio_enter(); |
368 | if (ret) |
369 | return ret; |
370 | |
371 | chip_type = superio_inw(DEVID); |
372 | if (chip_type != IT8712F_DEVID) |
373 | goto exit; |
374 | |
375 | superio_select(LDN_GAME); |
376 | superio_outb(1, ACT_REG); |
377 | if (!(superio_inb(ACT_REG) & 0x01)) { |
378 | pr_err("Device not activated, skipping\n"); |
379 | goto exit; |
380 | } |
381 | |
382 | *address = superio_inw(BASE_REG); |
383 | if (*address == 0) { |
384 | pr_err("Base address not set, skipping\n"); |
385 | goto exit; |
386 | } |
387 | |
388 | err = 0; |
389 | revision = superio_inb(DEVREV) & 0x0f; |
390 | |
391 | /* Later revisions have 16-bit values per datasheet 0.9.1 */ |
392 | if (revision >= 0x08) |
393 | max_units = 65535; |
394 | |
395 | if (margin > (max_units * 60)) |
396 | margin = (max_units * 60); |
397 | |
398 | pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n", |
399 | chip_type, revision, *address); |
400 | |
401 | exit: |
402 | superio_exit(); |
403 | return err; |
404 | } |
405 | |
406 | static int __init it8712f_wdt_init(void) |
407 | { |
408 | int err = 0; |
409 | |
410 | if (it8712f_wdt_find(&address)) |
411 | return -ENODEV; |
412 | |
413 | if (!request_region(address, 1, "IT8712F Watchdog")) { |
414 | pr_warn("watchdog I/O region busy\n"); |
415 | return -EBUSY; |
416 | } |
417 | |
418 | err = it8712f_wdt_disable(); |
419 | if (err) { |
420 | pr_err("unable to disable watchdog timer\n"); |
421 | goto out; |
422 | } |
423 | |
424 | err = register_reboot_notifier(&it8712f_wdt_notifier); |
425 | if (err) { |
426 | pr_err("unable to register reboot notifier\n"); |
427 | goto out; |
428 | } |
429 | |
430 | err = misc_register(&it8712f_wdt_miscdev); |
431 | if (err) { |
432 | pr_err("cannot register miscdev on minor=%d (err=%d)\n", |
433 | WATCHDOG_MINOR, err); |
434 | goto reboot_out; |
435 | } |
436 | |
437 | return 0; |
438 | |
439 | |
440 | reboot_out: |
441 | unregister_reboot_notifier(&it8712f_wdt_notifier); |
442 | out: |
443 | release_region(address, 1); |
444 | return err; |
445 | } |
446 | |
447 | static void __exit it8712f_wdt_exit(void) |
448 | { |
449 | misc_deregister(&it8712f_wdt_miscdev); |
450 | unregister_reboot_notifier(&it8712f_wdt_notifier); |
451 | release_region(address, 1); |
452 | } |
453 | |
454 | module_init(it8712f_wdt_init); |
455 | module_exit(it8712f_wdt_exit); |
456 |
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