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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");
44
45static int max_units = 255;
46static int margin = 60;
47module_param(margin, int, 0);
48MODULE_PARM_DESC(margin, "Watchdog margin in seconds");
49
50static bool nowayout = WATCHDOG_NOWAYOUT;
51module_param(nowayout, bool, 0);
52MODULE_PARM_DESC(nowayout, "Disable watchdog shutdown on close");
53
54static unsigned long wdt_open;
55static unsigned expect_close;
56static unsigned char revision;
57
58
59static unsigned short address;
60
61#define REG 0x2e
62#define VAL 0x2f
63
64#define LDN 0x07
65#define DEVID 0x20
66#define DEVREV 0x22
67#define ACT_REG 0x30
68#define BASE_REG 0x60
69
70#define IT8712F_DEVID 0x8712
71
72#define LDN_GPIO 0x07
73#define LDN_GAME 0x09
74
75#define WDT_CONTROL 0x71
76#define WDT_CONFIG 0x72
77#define WDT_TIMEOUT 0x73
78
79#define WDT_RESET_GAME 0x10
80#define WDT_RESET_KBD 0x20
81#define WDT_RESET_MOUSE 0x40
82#define WDT_RESET_CIR 0x80
83
84#define WDT_UNIT_SEC 0x80
85
86#define WDT_OUT_PWROK 0x10
87#define WDT_OUT_KRST 0x40
88
89static int wdt_control_reg = WDT_RESET_GAME;
90module_param(wdt_control_reg, int, 0);
91MODULE_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
97static int superio_inb(int reg)
98{
99 outb(reg, REG);
100 return inb(VAL);
101}
102
103static void superio_outb(int val, int reg)
104{
105 outb(reg, REG);
106 outb(val, VAL);
107}
108
109static 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
119static inline void superio_select(int ldn)
120{
121 outb(LDN, REG);
122 outb(ldn, VAL);
123}
124
125static inline int superio_enter(void)
126{
127
128
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
140static inline void superio_exit(void)
141{
142 outb(0x02, REG);
143 outb(0x02, VAL);
144 release_region(REG, 2);
145}
146
147static inline void it8712f_wdt_ping(void)
148{
149 if (wdt_control_reg & WDT_RESET_GAME)
150 inb(address);
151}
152
153static void it8712f_wdt_update_margin(void)
154{
155 int config = WDT_OUT_KRST | WDT_OUT_PWROK;
156 int units = margin;
157
158
159
160
161 if (units <= max_units) {
162 config |= WDT_UNIT_SEC;
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
175static 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
183static 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
203static 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
222static 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
232static struct notifier_block it8712f_wdt_notifier = {
233 .notifier_call = it8712f_wdt_notify,
234};
235
236static ssize_t it8712f_wdt_write(struct file *file, const char __user *data,
237 size_t len, loff_t *ppos)
238{
239
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
258static 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
311 case WDIOC_GETTIMEOUT:
312 if (put_user(margin, p))
313 return -EFAULT;
314 return 0;
315 default:
316 return -ENOTTY;
317 }
318}
319
320static int it8712f_wdt_open(struct inode *inode, struct file *file)
321{
322 int ret;
323
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
333static 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
347static 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
356static struct miscdevice it8712f_wdt_miscdev = {
357 .minor = WATCHDOG_MINOR,
358 .name = "watchdog",
359 .fops = &it8712f_wdt_fops,
360};
361
362static 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
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
400exit:
401 superio_exit();
402 return err;
403}
404
405static 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
439reboot_out:
440 unregister_reboot_notifier(&it8712f_wdt_notifier);
441out:
442 release_region(address, 1);
443 return err;
444}
445
446static 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
453module_init(it8712f_wdt_init);
454module_exit(it8712f_wdt_exit);
455
