1 /*
2 * Intel Management Engine Interface (Intel MEI) Linux driver
3 * Copyright (c) 2015, Intel Corporation.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms and conditions of the GNU General Public License,
7 * version 2, as published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
12 * more details.
13 */
14
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/interrupt.h>
18 #include <linux/debugfs.h>
19 #include <linux/completion.h>
20 #include <linux/watchdog.h>
21
22 #include <linux/uuid.h>
23 #include <linux/mei_cl_bus.h>
24
25 /*
26 * iAMT Watchdog Device
27 */
28 #define INTEL_AMT_WATCHDOG_ID "iamt_wdt"
29
30 #define MEI_WDT_DEFAULT_TIMEOUT 120 /* seconds */
31 #define MEI_WDT_MIN_TIMEOUT 120 /* seconds */
32 #define MEI_WDT_MAX_TIMEOUT 65535 /* seconds */
33
34 /* Commands */
35 #define MEI_MANAGEMENT_CONTROL 0x02
36
37 /* MEI Management Control version number */
38 #define MEI_MC_VERSION_NUMBER 0x10
39
40 /* Sub Commands */
41 #define MEI_MC_START_WD_TIMER_REQ 0x13
42 #define MEI_MC_START_WD_TIMER_RES 0x83
43 #define MEI_WDT_STATUS_SUCCESS 0
44 #define MEI_WDT_WDSTATE_NOT_REQUIRED 0x1
45 #define MEI_MC_STOP_WD_TIMER_REQ 0x14
46
47 /**
48 * enum mei_wdt_state - internal watchdog state
49 *
50 * @MEI_WDT_PROBE: wd in probing stage
51 * @MEI_WDT_IDLE: wd is idle and not opened
52 * @MEI_WDT_START: wd was opened, start was called
53 * @MEI_WDT_RUNNING: wd is expecting keep alive pings
54 * @MEI_WDT_STOPPING: wd is stopping and will move to IDLE
55 * @MEI_WDT_NOT_REQUIRED: wd device is not required
56 */
57 enum mei_wdt_state {
58 MEI_WDT_PROBE,
59 MEI_WDT_IDLE,
60 MEI_WDT_START,
61 MEI_WDT_RUNNING,
62 MEI_WDT_STOPPING,
63 MEI_WDT_NOT_REQUIRED,
64 };
65
mei_wdt_state_str(enum mei_wdt_state state)66 static const char *mei_wdt_state_str(enum mei_wdt_state state)
67 {
68 switch (state) {
69 case MEI_WDT_PROBE:
70 return "PROBE";
71 case MEI_WDT_IDLE:
72 return "IDLE";
73 case MEI_WDT_START:
74 return "START";
75 case MEI_WDT_RUNNING:
76 return "RUNNING";
77 case MEI_WDT_STOPPING:
78 return "STOPPING";
79 case MEI_WDT_NOT_REQUIRED:
80 return "NOT_REQUIRED";
81 default:
82 return "unknown";
83 }
84 }
85
86 /**
87 * struct mei_wdt - mei watchdog driver
88 * @wdd: watchdog device
89 *
90 * @cldev: mei watchdog client device
91 * @state: watchdog internal state
92 * @resp_required: ping required response
93 * @response: ping response completion
94 * @unregister: unregister worker
95 * @reg_lock: watchdog device registration lock
96 * @timeout: watchdog current timeout
97 *
98 * @dbgfs_dir: debugfs dir entry
99 */
100 struct mei_wdt {
101 struct watchdog_device wdd;
102
103 struct mei_cl_device *cldev;
104 enum mei_wdt_state state;
105 bool resp_required;
106 struct completion response;
107 struct work_struct unregister;
108 struct mutex reg_lock;
109 u16 timeout;
110
111 #if IS_ENABLED(CONFIG_DEBUG_FS)
112 struct dentry *dbgfs_dir;
113 #endif /* CONFIG_DEBUG_FS */
114 };
115
116 /*
117 * struct mei_mc_hdr - Management Control Command Header
118 *
119 * @command: Management Control (0x2)
120 * @bytecount: Number of bytes in the message beyond this byte
121 * @subcommand: Management Control Subcommand
122 * @versionnumber: Management Control Version (0x10)
123 */
124 struct mei_mc_hdr {
125 u8 command;
126 u8 bytecount;
127 u8 subcommand;
128 u8 versionnumber;
129 };
130
131 /**
132 * struct mei_wdt_start_request watchdog start/ping
133 *
134 * @hdr: Management Control Command Header
135 * @timeout: timeout value
136 * @reserved: reserved (legacy)
137 */
138 struct mei_wdt_start_request {
139 struct mei_mc_hdr hdr;
140 u16 timeout;
141 u8 reserved[17];
142 } __packed;
143
144 /**
145 * struct mei_wdt_start_response watchdog start/ping response
146 *
147 * @hdr: Management Control Command Header
148 * @status: operation status
149 * @wdstate: watchdog status bit mask
150 */
151 struct mei_wdt_start_response {
152 struct mei_mc_hdr hdr;
153 u8 status;
154 u8 wdstate;
155 } __packed;
156
157 /**
158 * struct mei_wdt_stop_request - watchdog stop
159 *
160 * @hdr: Management Control Command Header
161 */
162 struct mei_wdt_stop_request {
163 struct mei_mc_hdr hdr;
164 } __packed;
165
166 /**
167 * mei_wdt_ping - send wd start/ping command
168 *
169 * @wdt: mei watchdog device
170 *
171 * Return: 0 on success,
172 * negative errno code on failure
173 */
mei_wdt_ping(struct mei_wdt * wdt)174 static int mei_wdt_ping(struct mei_wdt *wdt)
175 {
176 struct mei_wdt_start_request req;
177 const size_t req_len = sizeof(req);
178 int ret;
179
180 memset(&req, 0, req_len);
181 req.hdr.command = MEI_MANAGEMENT_CONTROL;
182 req.hdr.bytecount = req_len - offsetof(struct mei_mc_hdr, subcommand);
183 req.hdr.subcommand = MEI_MC_START_WD_TIMER_REQ;
184 req.hdr.versionnumber = MEI_MC_VERSION_NUMBER;
185 req.timeout = wdt->timeout;
186
187 ret = mei_cldev_send(wdt->cldev, (u8 *)&req, req_len);
188 if (ret < 0)
189 return ret;
190
191 return 0;
192 }
193
194 /**
195 * mei_wdt_stop - send wd stop command
196 *
197 * @wdt: mei watchdog device
198 *
199 * Return: 0 on success,
200 * negative errno code on failure
201 */
mei_wdt_stop(struct mei_wdt * wdt)202 static int mei_wdt_stop(struct mei_wdt *wdt)
203 {
204 struct mei_wdt_stop_request req;
205 const size_t req_len = sizeof(req);
206 int ret;
207
208 memset(&req, 0, req_len);
209 req.hdr.command = MEI_MANAGEMENT_CONTROL;
210 req.hdr.bytecount = req_len - offsetof(struct mei_mc_hdr, subcommand);
211 req.hdr.subcommand = MEI_MC_STOP_WD_TIMER_REQ;
212 req.hdr.versionnumber = MEI_MC_VERSION_NUMBER;
213
214 ret = mei_cldev_send(wdt->cldev, (u8 *)&req, req_len);
215 if (ret < 0)
216 return ret;
217
218 return 0;
219 }
220
221 /**
222 * mei_wdt_ops_start - wd start command from the watchdog core.
223 *
224 * @wdd: watchdog device
225 *
226 * Return: 0 on success or -ENODEV;
227 */
mei_wdt_ops_start(struct watchdog_device * wdd)228 static int mei_wdt_ops_start(struct watchdog_device *wdd)
229 {
230 struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
231
232 wdt->state = MEI_WDT_START;
233 wdd->timeout = wdt->timeout;
234 return 0;
235 }
236
237 /**
238 * mei_wdt_ops_stop - wd stop command from the watchdog core.
239 *
240 * @wdd: watchdog device
241 *
242 * Return: 0 if success, negative errno code for failure
243 */
mei_wdt_ops_stop(struct watchdog_device * wdd)244 static int mei_wdt_ops_stop(struct watchdog_device *wdd)
245 {
246 struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
247 int ret;
248
249 if (wdt->state != MEI_WDT_RUNNING)
250 return 0;
251
252 wdt->state = MEI_WDT_STOPPING;
253
254 ret = mei_wdt_stop(wdt);
255 if (ret)
256 return ret;
257
258 wdt->state = MEI_WDT_IDLE;
259
260 return 0;
261 }
262
263 /**
264 * mei_wdt_ops_ping - wd ping command from the watchdog core.
265 *
266 * @wdd: watchdog device
267 *
268 * Return: 0 if success, negative errno code on failure
269 */
mei_wdt_ops_ping(struct watchdog_device * wdd)270 static int mei_wdt_ops_ping(struct watchdog_device *wdd)
271 {
272 struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
273 int ret;
274
275 if (wdt->state != MEI_WDT_START && wdt->state != MEI_WDT_RUNNING)
276 return 0;
277
278 if (wdt->resp_required)
279 init_completion(&wdt->response);
280
281 wdt->state = MEI_WDT_RUNNING;
282 ret = mei_wdt_ping(wdt);
283 if (ret)
284 return ret;
285
286 if (wdt->resp_required)
287 ret = wait_for_completion_killable(&wdt->response);
288
289 return ret;
290 }
291
292 /**
293 * mei_wdt_ops_set_timeout - wd set timeout command from the watchdog core.
294 *
295 * @wdd: watchdog device
296 * @timeout: timeout value to set
297 *
298 * Return: 0 if success, negative errno code for failure
299 */
mei_wdt_ops_set_timeout(struct watchdog_device * wdd,unsigned int timeout)300 static int mei_wdt_ops_set_timeout(struct watchdog_device *wdd,
301 unsigned int timeout)
302 {
303
304 struct mei_wdt *wdt = watchdog_get_drvdata(wdd);
305
306 /* valid value is already checked by the caller */
307 wdt->timeout = timeout;
308 wdd->timeout = timeout;
309
310 return 0;
311 }
312
313 static const struct watchdog_ops wd_ops = {
314 .owner = THIS_MODULE,
315 .start = mei_wdt_ops_start,
316 .stop = mei_wdt_ops_stop,
317 .ping = mei_wdt_ops_ping,
318 .set_timeout = mei_wdt_ops_set_timeout,
319 };
320
321 /* not const as the firmware_version field need to be retrieved */
322 static struct watchdog_info wd_info = {
323 .identity = INTEL_AMT_WATCHDOG_ID,
324 .options = WDIOF_KEEPALIVEPING |
325 WDIOF_SETTIMEOUT |
326 WDIOF_ALARMONLY,
327 };
328
329 /**
330 * __mei_wdt_is_registered - check if wdt is registered
331 *
332 * @wdt: mei watchdog device
333 *
334 * Return: true if the wdt is registered with the watchdog subsystem
335 * Locking: should be called under wdt->reg_lock
336 */
__mei_wdt_is_registered(struct mei_wdt * wdt)337 static inline bool __mei_wdt_is_registered(struct mei_wdt *wdt)
338 {
339 return !!watchdog_get_drvdata(&wdt->wdd);
340 }
341
342 /**
343 * mei_wdt_unregister - unregister from the watchdog subsystem
344 *
345 * @wdt: mei watchdog device
346 */
mei_wdt_unregister(struct mei_wdt * wdt)347 static void mei_wdt_unregister(struct mei_wdt *wdt)
348 {
349 mutex_lock(&wdt->reg_lock);
350
351 if (__mei_wdt_is_registered(wdt)) {
352 watchdog_unregister_device(&wdt->wdd);
353 watchdog_set_drvdata(&wdt->wdd, NULL);
354 memset(&wdt->wdd, 0, sizeof(wdt->wdd));
355 }
356
357 mutex_unlock(&wdt->reg_lock);
358 }
359
360 /**
361 * mei_wdt_register - register with the watchdog subsystem
362 *
363 * @wdt: mei watchdog device
364 *
365 * Return: 0 if success, negative errno code for failure
366 */
mei_wdt_register(struct mei_wdt * wdt)367 static int mei_wdt_register(struct mei_wdt *wdt)
368 {
369 struct device *dev;
370 int ret;
371
372 if (!wdt || !wdt->cldev)
373 return -EINVAL;
374
375 dev = &wdt->cldev->dev;
376
377 mutex_lock(&wdt->reg_lock);
378
379 if (__mei_wdt_is_registered(wdt)) {
380 ret = 0;
381 goto out;
382 }
383
384 wdt->wdd.info = &wd_info;
385 wdt->wdd.ops = &wd_ops;
386 wdt->wdd.parent = dev;
387 wdt->wdd.timeout = MEI_WDT_DEFAULT_TIMEOUT;
388 wdt->wdd.min_timeout = MEI_WDT_MIN_TIMEOUT;
389 wdt->wdd.max_timeout = MEI_WDT_MAX_TIMEOUT;
390
391 watchdog_set_drvdata(&wdt->wdd, wdt);
392 watchdog_stop_on_reboot(&wdt->wdd);
393
394 ret = watchdog_register_device(&wdt->wdd);
395 if (ret) {
396 dev_err(dev, "unable to register watchdog device = %d.\n", ret);
397 watchdog_set_drvdata(&wdt->wdd, NULL);
398 }
399
400 wdt->state = MEI_WDT_IDLE;
401
402 out:
403 mutex_unlock(&wdt->reg_lock);
404 return ret;
405 }
406
mei_wdt_unregister_work(struct work_struct * work)407 static void mei_wdt_unregister_work(struct work_struct *work)
408 {
409 struct mei_wdt *wdt = container_of(work, struct mei_wdt, unregister);
410
411 mei_wdt_unregister(wdt);
412 }
413
414 /**
415 * mei_wdt_event_rx - callback for data receive
416 *
417 * @cldev: bus device
418 */
mei_wdt_event_rx(struct mei_cl_device * cldev)419 static void mei_wdt_event_rx(struct mei_cl_device *cldev)
420 {
421 struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
422 struct mei_wdt_start_response res;
423 const size_t res_len = sizeof(res);
424 int ret;
425
426 ret = mei_cldev_recv(wdt->cldev, (u8 *)&res, res_len);
427 if (ret < 0) {
428 dev_err(&cldev->dev, "failure in recv %d\n", ret);
429 return;
430 }
431
432 /* Empty response can be sent on stop */
433 if (ret == 0)
434 return;
435
436 if (ret < sizeof(struct mei_mc_hdr)) {
437 dev_err(&cldev->dev, "recv small data %d\n", ret);
438 return;
439 }
440
441 if (res.hdr.command != MEI_MANAGEMENT_CONTROL ||
442 res.hdr.versionnumber != MEI_MC_VERSION_NUMBER) {
443 dev_err(&cldev->dev, "wrong command received\n");
444 return;
445 }
446
447 if (res.hdr.subcommand != MEI_MC_START_WD_TIMER_RES) {
448 dev_warn(&cldev->dev, "unsupported command %d :%s[%d]\n",
449 res.hdr.subcommand,
450 mei_wdt_state_str(wdt->state),
451 wdt->state);
452 return;
453 }
454
455 /* Run the unregistration in a worker as this can be
456 * run only after ping completion, otherwise the flow will
457 * deadlock on watchdog core mutex.
458 */
459 if (wdt->state == MEI_WDT_RUNNING) {
460 if (res.wdstate & MEI_WDT_WDSTATE_NOT_REQUIRED) {
461 wdt->state = MEI_WDT_NOT_REQUIRED;
462 schedule_work(&wdt->unregister);
463 }
464 goto out;
465 }
466
467 if (wdt->state == MEI_WDT_PROBE) {
468 if (res.wdstate & MEI_WDT_WDSTATE_NOT_REQUIRED) {
469 wdt->state = MEI_WDT_NOT_REQUIRED;
470 } else {
471 /* stop the watchdog and register watchdog device */
472 mei_wdt_stop(wdt);
473 mei_wdt_register(wdt);
474 }
475 return;
476 }
477
478 dev_warn(&cldev->dev, "not in correct state %s[%d]\n",
479 mei_wdt_state_str(wdt->state), wdt->state);
480
481 out:
482 if (!completion_done(&wdt->response))
483 complete(&wdt->response);
484 }
485
486 /*
487 * mei_wdt_notify_event - callback for event notification
488 *
489 * @cldev: bus device
490 */
mei_wdt_notify_event(struct mei_cl_device * cldev)491 static void mei_wdt_notify_event(struct mei_cl_device *cldev)
492 {
493 struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
494
495 if (wdt->state != MEI_WDT_NOT_REQUIRED)
496 return;
497
498 mei_wdt_register(wdt);
499 }
500
501 /**
502 * mei_wdt_event - callback for event receive
503 *
504 * @cldev: bus device
505 * @events: event mask
506 * @context: callback context
507 */
mei_wdt_event(struct mei_cl_device * cldev,u32 events,void * context)508 static void mei_wdt_event(struct mei_cl_device *cldev,
509 u32 events, void *context)
510 {
511 if (events & BIT(MEI_CL_EVENT_RX))
512 mei_wdt_event_rx(cldev);
513
514 if (events & BIT(MEI_CL_EVENT_NOTIF))
515 mei_wdt_notify_event(cldev);
516 }
517
518 #if IS_ENABLED(CONFIG_DEBUG_FS)
519
mei_dbgfs_read_activation(struct file * file,char __user * ubuf,size_t cnt,loff_t * ppos)520 static ssize_t mei_dbgfs_read_activation(struct file *file, char __user *ubuf,
521 size_t cnt, loff_t *ppos)
522 {
523 struct mei_wdt *wdt = file->private_data;
524 const size_t bufsz = 32;
525 char buf[32];
526 ssize_t pos;
527
528 mutex_lock(&wdt->reg_lock);
529 pos = scnprintf(buf, bufsz, "%s\n",
530 __mei_wdt_is_registered(wdt) ? "activated" : "deactivated");
531 mutex_unlock(&wdt->reg_lock);
532
533 return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
534 }
535
536 static const struct file_operations dbgfs_fops_activation = {
537 .open = simple_open,
538 .read = mei_dbgfs_read_activation,
539 .llseek = generic_file_llseek,
540 };
541
mei_dbgfs_read_state(struct file * file,char __user * ubuf,size_t cnt,loff_t * ppos)542 static ssize_t mei_dbgfs_read_state(struct file *file, char __user *ubuf,
543 size_t cnt, loff_t *ppos)
544 {
545 struct mei_wdt *wdt = file->private_data;
546 const size_t bufsz = 32;
547 char buf[bufsz];
548 ssize_t pos;
549
550 pos = scnprintf(buf, bufsz, "state: %s\n",
551 mei_wdt_state_str(wdt->state));
552
553 return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
554 }
555
556 static const struct file_operations dbgfs_fops_state = {
557 .open = simple_open,
558 .read = mei_dbgfs_read_state,
559 .llseek = generic_file_llseek,
560 };
561
dbgfs_unregister(struct mei_wdt * wdt)562 static void dbgfs_unregister(struct mei_wdt *wdt)
563 {
564 debugfs_remove_recursive(wdt->dbgfs_dir);
565 wdt->dbgfs_dir = NULL;
566 }
567
dbgfs_register(struct mei_wdt * wdt)568 static int dbgfs_register(struct mei_wdt *wdt)
569 {
570 struct dentry *dir, *f;
571
572 dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
573 if (!dir)
574 return -ENOMEM;
575
576 wdt->dbgfs_dir = dir;
577 f = debugfs_create_file("state", S_IRUSR, dir, wdt, &dbgfs_fops_state);
578 if (!f)
579 goto err;
580
581 f = debugfs_create_file("activation", S_IRUSR,
582 dir, wdt, &dbgfs_fops_activation);
583 if (!f)
584 goto err;
585
586 return 0;
587 err:
588 dbgfs_unregister(wdt);
589 return -ENODEV;
590 }
591
592 #else
593
dbgfs_unregister(struct mei_wdt * wdt)594 static inline void dbgfs_unregister(struct mei_wdt *wdt) {}
595
dbgfs_register(struct mei_wdt * wdt)596 static inline int dbgfs_register(struct mei_wdt *wdt)
597 {
598 return 0;
599 }
600 #endif /* CONFIG_DEBUG_FS */
601
mei_wdt_probe(struct mei_cl_device * cldev,const struct mei_cl_device_id * id)602 static int mei_wdt_probe(struct mei_cl_device *cldev,
603 const struct mei_cl_device_id *id)
604 {
605 struct mei_wdt *wdt;
606 int ret;
607
608 wdt = kzalloc(sizeof(struct mei_wdt), GFP_KERNEL);
609 if (!wdt)
610 return -ENOMEM;
611
612 wdt->timeout = MEI_WDT_DEFAULT_TIMEOUT;
613 wdt->state = MEI_WDT_PROBE;
614 wdt->cldev = cldev;
615 wdt->resp_required = mei_cldev_ver(cldev) > 0x1;
616 mutex_init(&wdt->reg_lock);
617 init_completion(&wdt->response);
618 INIT_WORK(&wdt->unregister, mei_wdt_unregister_work);
619
620 mei_cldev_set_drvdata(cldev, wdt);
621
622 ret = mei_cldev_enable(cldev);
623 if (ret < 0) {
624 dev_err(&cldev->dev, "Could not enable cl device\n");
625 goto err_out;
626 }
627
628 ret = mei_cldev_register_event_cb(wdt->cldev,
629 BIT(MEI_CL_EVENT_RX) |
630 BIT(MEI_CL_EVENT_NOTIF),
631 mei_wdt_event, NULL);
632
633 /* on legacy devices notification is not supported
634 * this doesn't fail the registration for RX event
635 */
636 if (ret && ret != -EOPNOTSUPP) {
637 dev_err(&cldev->dev, "Could not register event ret=%d\n", ret);
638 goto err_disable;
639 }
640
641 wd_info.firmware_version = mei_cldev_ver(cldev);
642
643 if (wdt->resp_required)
644 ret = mei_wdt_ping(wdt);
645 else
646 ret = mei_wdt_register(wdt);
647
648 if (ret)
649 goto err_disable;
650
651 if (dbgfs_register(wdt))
652 dev_warn(&cldev->dev, "cannot register debugfs\n");
653
654 return 0;
655
656 err_disable:
657 mei_cldev_disable(cldev);
658
659 err_out:
660 kfree(wdt);
661
662 return ret;
663 }
664
mei_wdt_remove(struct mei_cl_device * cldev)665 static int mei_wdt_remove(struct mei_cl_device *cldev)
666 {
667 struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
668
669 /* Free the caller in case of fw initiated or unexpected reset */
670 if (!completion_done(&wdt->response))
671 complete(&wdt->response);
672
673 cancel_work_sync(&wdt->unregister);
674
675 mei_wdt_unregister(wdt);
676
677 mei_cldev_disable(cldev);
678
679 dbgfs_unregister(wdt);
680
681 kfree(wdt);
682
683 return 0;
684 }
685
686 #define MEI_UUID_WD UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, \
687 0x89, 0x9D, 0xA9, 0x15, 0x14, 0xCB, 0x32, 0xAB)
688
689 static struct mei_cl_device_id mei_wdt_tbl[] = {
690 { .uuid = MEI_UUID_WD, .version = MEI_CL_VERSION_ANY },
691 /* required last entry */
692 { }
693 };
694 MODULE_DEVICE_TABLE(mei, mei_wdt_tbl);
695
696 static struct mei_cl_driver mei_wdt_driver = {
697 .id_table = mei_wdt_tbl,
698 .name = KBUILD_MODNAME,
699
700 .probe = mei_wdt_probe,
701 .remove = mei_wdt_remove,
702 };
703
mei_wdt_init(void)704 static int __init mei_wdt_init(void)
705 {
706 int ret;
707
708 ret = mei_cldev_driver_register(&mei_wdt_driver);
709 if (ret) {
710 pr_err(KBUILD_MODNAME ": module registration failed\n");
711 return ret;
712 }
713 return 0;
714 }
715
mei_wdt_exit(void)716 static void __exit mei_wdt_exit(void)
717 {
718 mei_cldev_driver_unregister(&mei_wdt_driver);
719 }
720
721 module_init(mei_wdt_init);
722 module_exit(mei_wdt_exit);
723
724 MODULE_AUTHOR("Intel Corporation");
725 MODULE_LICENSE("GPL");
726 MODULE_DESCRIPTION("Device driver for Intel MEI iAMT watchdog");
727