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19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
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>
28#include <linux/fs.h>
29#include <linux/spinlock.h>
30#include <linux/uaccess.h>
31#include <linux/io.h>
32#include <linux/ioport.h>
33
34#define DEBUG
35#define NAME "it8712f_wdt"
36
37MODULE_AUTHOR("Jorge Boncompte - DTI2 <jorge@dti2.net>");
38MODULE_DESCRIPTION("IT8712F Watchdog Driver");
39MODULE_LICENSE("GPL");
40
41static int max_units = 255;
42static int margin = 60;
43module_param(margin, int, 0);
44MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
45
46static bool nowayout = WATCHDOG_NOWAYOUT;
47module_param(nowayout, bool, 0);
48MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
49
50static unsigned long wdt_open;
51static unsigned expect_close;
52static unsigned char revision;
53
54
55static unsigned short address;
56
57#define REG 0x2e
58#define VAL 0x2f
59
60#define LDN 0x07
61#define DEVID 0x20
62#define DEVREV 0x22
63#define ACT_REG 0x30
64#define BASE_REG 0x60
65
66#define IT8712F_DEVID 0x8712
67
68#define LDN_GPIO 0x07
69#define LDN_GAME 0x09
70
71#define WDT_CONTROL 0x71
72#define WDT_CONFIG 0x72
73#define WDT_TIMEOUT 0x73
74
75#define WDT_RESET_GAME 0x10
76#define WDT_RESET_KBD 0x20
77#define WDT_RESET_MOUSE 0x40
78#define WDT_RESET_CIR 0x80
79
80#define WDT_UNIT_SEC 0x80
81
82#define WDT_OUT_PWROK 0x10
83#define WDT_OUT_KRST 0x40
84
85static int wdt_control_reg = WDT_RESET_GAME;
86module_param(wdt_control_reg, int, 0);
87MODULE_PARM_DESC(wdt_control_reg, "Value to write to watchdog control "
88 "register. The default WDT_RESET_GAME resets the timer on "
89 "game port reads that this driver generates. You can also "
90 "use KBD, MOUSE or CIR if you have some external way to "
91 "generate those interrupts.");
92
93static int superio_inb(int reg)
94{
95 outb(reg, REG);
96 return inb(VAL);
97}
98
99static void superio_outb(int val, int reg)
100{
101 outb(reg, REG);
102 outb(val, VAL);
103}
104
105static int superio_inw(int reg)
106{
107 int val;
108 outb(reg++, REG);
109 val = inb(VAL) << 8;
110 outb(reg, REG);
111 val |= inb(VAL);
112 return val;
113}
114
115static inline void superio_select(int ldn)
116{
117 outb(LDN, REG);
118 outb(ldn, VAL);
119}
120
121static inline int superio_enter(void)
122{
123
124
125
126 if (!request_muxed_region(REG, 2, NAME))
127 return -EBUSY;
128
129 outb(0x87, REG);
130 outb(0x01, REG);
131 outb(0x55, REG);
132 outb(0x55, REG);
133 return 0;
134}
135
136static inline void superio_exit(void)
137{
138 outb(0x02, REG);
139 outb(0x02, VAL);
140 release_region(REG, 2);
141}
142
143static inline void it8712f_wdt_ping(void)
144{
145 if (wdt_control_reg & WDT_RESET_GAME)
146 inb(address);
147}
148
149static void it8712f_wdt_update_margin(void)
150{
151 int config = WDT_OUT_KRST | WDT_OUT_PWROK;
152 int units = margin;
153
154
155
156
157 if (units <= max_units) {
158 config |= WDT_UNIT_SEC;
159 pr_info("timer margin %d seconds\n", units);
160 } else {
161 units /= 60;
162 pr_info("timer margin %d minutes\n", units);
163 }
164 superio_outb(config, WDT_CONFIG);
165
166 if (revision >= 0x08)
167 superio_outb(units >> 8, WDT_TIMEOUT + 1);
168 superio_outb(units, WDT_TIMEOUT);
169}
170
171static int it8712f_wdt_get_status(void)
172{
173 if (superio_inb(WDT_CONTROL) & 0x01)
174 return WDIOF_CARDRESET;
175 else
176 return 0;
177}
178
179static int it8712f_wdt_enable(void)
180{
181 int ret = superio_enter();
182 if (ret)
183 return ret;
184
185 pr_debug("enabling watchdog timer\n");
186 superio_select(LDN_GPIO);
187
188 superio_outb(wdt_control_reg, WDT_CONTROL);
189
190 it8712f_wdt_update_margin();
191
192 superio_exit();
193
194 it8712f_wdt_ping();
195
196 return 0;
197}
198
199static int it8712f_wdt_disable(void)
200{
201 int ret = superio_enter();
202 if (ret)
203 return ret;
204
205 pr_debug("disabling watchdog timer\n");
206 superio_select(LDN_GPIO);
207
208 superio_outb(0, WDT_CONFIG);
209 superio_outb(0, WDT_CONTROL);
210 if (revision >= 0x08)
211 superio_outb(0, WDT_TIMEOUT + 1);
212 superio_outb(0, WDT_TIMEOUT);
213
214 superio_exit();
215 return 0;
216}
217
218static int it8712f_wdt_notify(struct notifier_block *this,
219 unsigned long code, void *unused)
220{
221 if (code == SYS_HALT || code == SYS_POWER_OFF)
222 if (!nowayout)
223 it8712f_wdt_disable();
224
225 return NOTIFY_DONE;
226}
227
228static struct notifier_block it8712f_wdt_notifier = {
229 .notifier_call = it8712f_wdt_notify,
230};
231
232static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
233 size_t len, loff_t *ppos)
234{
235
236 if (len) {
237 size_t i;
238
239 it8712f_wdt_ping();
240
241 expect_close = 0;
242 for (i = 0; i < len; ++i) {
243 char c;
244 if (get_user(c, data + i))
245 return -EFAULT;
246 if (c == 'V')
247 expect_close = 42;
248 }
249 }
250
251 return len;
252}
253
254static long it8712f_wdt_ioctl(struct file *file, unsigned int cmd,
255 unsigned long arg)
256{
257 void __user *argp = (void __user *)arg;
258 int __user *p = argp;
259 static const struct watchdog_info ident = {
260 .identity = "IT8712F Watchdog",
261 .firmware_version = 1,
262 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
263 WDIOF_MAGICCLOSE,
264 };
265 int value;
266 int ret;
267
268 switch (cmd) {
269 case WDIOC_GETSUPPORT:
270 if (copy_to_user(argp, &ident, sizeof(ident)))
271 return -EFAULT;
272 return 0;
273 case WDIOC_GETSTATUS:
274 ret = superio_enter();
275 if (ret)
276 return ret;
277 superio_select(LDN_GPIO);
278
279 value = it8712f_wdt_get_status();
280
281 superio_exit();
282
283 return put_user(value, p);
284 case WDIOC_GETBOOTSTATUS:
285 return put_user(0, p);
286 case WDIOC_KEEPALIVE:
287 it8712f_wdt_ping();
288 return 0;
289 case WDIOC_SETTIMEOUT:
290 if (get_user(value, p))
291 return -EFAULT;
292 if (value < 1)
293 return -EINVAL;
294 if (value > (max_units * 60))
295 return -EINVAL;
296 margin = value;
297 ret = superio_enter();
298 if (ret)
299 return ret;
300 superio_select(LDN_GPIO);
301
302 it8712f_wdt_update_margin();
303
304 superio_exit();
305 it8712f_wdt_ping();
306
307 case WDIOC_GETTIMEOUT:
308 if (put_user(margin, p))
309 return -EFAULT;
310 return 0;
311 default:
312 return -ENOTTY;
313 }
314}
315
316static int it8712f_wdt_open(struct inode *inode, struct file *file)
317{
318 int ret;
319
320 if (test_and_set_bit(0, &wdt_open))
321 return -EBUSY;
322
323 ret = it8712f_wdt_enable();
324 if (ret)
325 return ret;
326 return stream_open(inode, file);
327}
328
329static int it8712f_wdt_release(struct inode *inode, struct file *file)
330{
331 if (expect_close != 42) {
332 pr_warn("watchdog device closed unexpectedly, will not disable the watchdog timer\n");
333 } else if (!nowayout) {
334 if (it8712f_wdt_disable())
335 pr_warn("Watchdog disable failed\n");
336 }
337 expect_close = 0;
338 clear_bit(0, &wdt_open);
339
340 return 0;
341}
342
343static const struct file_operations it8712f_wdt_fops = {
344 .owner = THIS_MODULE,
345 .llseek = no_llseek,
346 .write = it8712f_wdt_write,
347 .unlocked_ioctl = it8712f_wdt_ioctl,
348 .open = it8712f_wdt_open,
349 .release = it8712f_wdt_release,
350};
351
352static struct miscdevice it8712f_wdt_miscdev = {
353 .minor = WATCHDOG_MINOR,
354 .name = "watchdog",
355 .fops = &it8712f_wdt_fops,
356};
357
358static int __init it8712f_wdt_find(unsigned short *address)
359{
360 int err = -ENODEV;
361 int chip_type;
362 int ret = superio_enter();
363 if (ret)
364 return ret;
365
366 chip_type = superio_inw(DEVID);
367 if (chip_type != IT8712F_DEVID)
368 goto exit;
369
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");
374 goto exit;
375 }
376
377 *address = superio_inw(BASE_REG);
378 if (*address == 0) {
379 pr_err("Base address not set, skipping\n");
380 goto exit;
381 }
382
383 err = 0;
384 revision = superio_inb(DEVREV) & 0x0f;
385
386
387 if (revision >= 0x08)
388 max_units = 65535;
389
390 if (margin > (max_units * 60))
391 margin = (max_units * 60);
392
393 pr_info("Found IT%04xF chip revision %d - using DogFood address 0x%x\n",
394 chip_type, revision, *address);
395
396exit:
397 superio_exit();
398 return err;
399}
400
401static int __init it8712f_wdt_init(void)
402{
403 int err = 0;
404
405 if (it8712f_wdt_find(&address))
406 return -ENODEV;
407
408 if (!request_region(address, 1, "IT8712F Watchdog")) {
409 pr_warn("watchdog I/O region busy\n");
410 return -EBUSY;
411 }
412
413 err = it8712f_wdt_disable();
414 if (err) {
415 pr_err("unable to disable watchdog timer\n");
416 goto out;
417 }
418
419 err = register_reboot_notifier(&it8712f_wdt_notifier);
420 if (err) {
421 pr_err("unable to register reboot notifier\n");
422 goto out;
423 }
424
425 err = misc_register(&it8712f_wdt_miscdev);
426 if (err) {
427 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
428 WATCHDOG_MINOR, err);
429 goto reboot_out;
430 }
431
432 return 0;
433
434
435reboot_out:
436 unregister_reboot_notifier(&it8712f_wdt_notifier);
437out:
438 release_region(address, 1);
439 return err;
440}
441
442static void __exit it8712f_wdt_exit(void)
443{
444 misc_deregister(&it8712f_wdt_miscdev);
445 unregister_reboot_notifier(&it8712f_wdt_notifier);
446 release_region(address, 1);
447}
448
449module_init(it8712f_wdt_init);
450module_exit(it8712f_wdt_exit);
451
