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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
41MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
42MODULE_DESCRIPTION("IT8712F Watchdog Driver");
43MODULE_LICENSE("GPL");
44MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
45
46static int max_units = 255;
47static int margin = 60;
48module_param(margin, int, 0);
49MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
50
51static bool nowayout = WATCHDOG_NOWAYOUT;
52module_param(nowayout, bool, 0);
53MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
54
55static unsigned long wdt_open;
56static unsigned expect_close;
57static unsigned char revision;
58
59
60static unsigned short address;
61
62#define REG 0x2e
63#define VAL 0x2f
64
65#define LDN 0x07
66#define DEVID 0x20
67#define DEVREV 0x22
68#define ACT_REG 0x30
69#define BASE_REG 0x60
70
71#define IT8712F_DEVID 0x8712
72
73#define LDN_GPIO 0x07
74#define LDN_GAME 0x09
75
76#define WDT_CONTROL 0x71
77#define WDT_CONFIG 0x72
78#define WDT_TIMEOUT 0x73
79
80#define WDT_RESET_GAME 0x10
81#define WDT_RESET_KBD 0x20
82#define WDT_RESET_MOUSE 0x40
83#define WDT_RESET_CIR 0x80
84
85#define WDT_UNIT_SEC 0x80
86
87#define WDT_OUT_PWROK 0x10
88#define WDT_OUT_KRST 0x40
89
90static int wdt_control_reg = WDT_RESET_GAME;
91module_param(wdt_control_reg, int, 0);
92MODULE_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
98static int superio_inb(int reg)
99{
100 outb(reg, REG);
101 return inb(VAL);
102}
103
104static void superio_outb(int val, int reg)
105{
106 outb(reg, REG);
107 outb(val, VAL);
108}
109
110static 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
120static inline void superio_select(int ldn)
121{
122 outb(LDN, REG);
123 outb(ldn, VAL);
124}
125
126static inline int superio_enter(void)
127{
128
129
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
141static inline void superio_exit(void)
142{
143 outb(0x02, REG);
144 outb(0x02, VAL);
145 release_region(REG, 2);
146}
147
148static inline void it8712f_wdt_ping(void)
149{
150 if (wdt_control_reg & WDT_RESET_GAME)
151 inb(address);
152}
153
154static void it8712f_wdt_update_margin(void)
155{
156 int config = WDT_OUT_KRST | WDT_OUT_PWROK;
157 int units = margin;
158
159
160
161
162 if (units <= max_units) {
163 config |= WDT_UNIT_SEC;
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
176static 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
184static 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
204static 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
223static 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
233static struct notifier_block it8712f_wdt_notifier = {
234 .notifier_call = it8712f_wdt_notify,
235};
236
237static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
238 size_t len, loff_t *ppos)
239{
240
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
259static 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
312 case WDIOC_GETTIMEOUT:
313 if (put_user(margin, p))
314 return -EFAULT;
315 return 0;
316 default:
317 return -ENOTTY;
318 }
319}
320
321static int it8712f_wdt_open(struct inode *inode, struct file *file)
322{
323 int ret;
324
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
334static 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
348static 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
357static struct miscdevice it8712f_wdt_miscdev = {
358 .minor = WATCHDOG_MINOR,
359 .name = "watchdog",
360 .fops = &it8712f_wdt_fops,
361};
362
363static 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
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
401exit:
402 superio_exit();
403 return err;
404}
405
406static 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
440reboot_out:
441 unregister_reboot_notifier(&it8712f_wdt_notifier);
442out:
443 release_region(address, 1);
444 return err;
445}
446
447static 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
454module_init(it8712f_wdt_init);
455module_exit(it8712f_wdt_exit);
456
