drivers/watchdog/mei_wdt.c

   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
  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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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         ret = watchdog_register_device(&wdt->wdd);
 393         if (ret) {
 394                 dev_err(dev, "unable to register watchdog device = %d.\n", ret);
 395                 watchdog_set_drvdata(&wdt->wdd, NULL);
 396         }
 397
 398         wdt->state = MEI_WDT_IDLE;
 399
 400 out:
 401         mutex_unlock(&wdt->reg_lock);
 402         return ret;
 403 }
 404
 405 static void mei_wdt_unregister_work(struct work_struct *work)
 406 {
 407         struct mei_wdt *wdt = container_of(work, struct mei_wdt, unregister);
 408
 409         mei_wdt_unregister(wdt);
 410 }
 411
 412 /**
 413  * mei_wdt_event_rx - callback for data receive
 414  *
 415  * @cldev: bus device
 416  */
 417 static void mei_wdt_event_rx(struct mei_cl_device *cldev)
 418 {
 419         struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
 420         struct mei_wdt_start_response res;
 421         const size_t res_len = sizeof(res);
 422         int ret;
 423
 424         ret = mei_cldev_recv(wdt->cldev, (u8 *)&res, res_len);
 425         if (ret < 0) {
 426                 dev_err(&cldev->dev, "failure in recv %d\n", ret);
 427                 return;
 428         }
 429
 430         /* Empty response can be sent on stop */
 431         if (ret == 0)
 432                 return;
 433
 434         if (ret < sizeof(struct mei_mc_hdr)) {
 435                 dev_err(&cldev->dev, "recv small data %d\n", ret);
 436                 return;
 437         }
 438
 439         if (res.hdr.command != MEI_MANAGEMENT_CONTROL ||
 440             res.hdr.versionnumber != MEI_MC_VERSION_NUMBER) {
 441                 dev_err(&cldev->dev, "wrong command received\n");
 442                 return;
 443         }
 444
 445         if (res.hdr.subcommand != MEI_MC_START_WD_TIMER_RES) {
 446                 dev_warn(&cldev->dev, "unsupported command %d :%s[%d]\n",
 447                          res.hdr.subcommand,
 448                          mei_wdt_state_str(wdt->state),
 449                          wdt->state);
 450                 return;
 451         }
 452
 453         /* Run the unregistration in a worker as this can be
 454          * run only after ping completion, otherwise the flow will
 455          * deadlock on watchdog core mutex.
 456          */
 457         if (wdt->state == MEI_WDT_RUNNING) {
 458                 if (res.wdstate & MEI_WDT_WDSTATE_NOT_REQUIRED) {
 459                         wdt->state = MEI_WDT_NOT_REQUIRED;
 460                         schedule_work(&wdt->unregister);
 461                 }
 462                 goto out;
 463         }
 464
 465         if (wdt->state == MEI_WDT_PROBE) {
 466                 if (res.wdstate & MEI_WDT_WDSTATE_NOT_REQUIRED) {
 467                         wdt->state = MEI_WDT_NOT_REQUIRED;
 468                 } else {
 469                         /* stop the watchdog and register watchdog device */
 470                         mei_wdt_stop(wdt);
 471                         mei_wdt_register(wdt);
 472                 }
 473                 return;
 474         }
 475
 476         dev_warn(&cldev->dev, "not in correct state %s[%d]\n",
 477                          mei_wdt_state_str(wdt->state), wdt->state);
 478
 479 out:
 480         if (!completion_done(&wdt->response))
 481                 complete(&wdt->response);
 482 }
 483
 484 /*
 485  * mei_wdt_notify_event - callback for event notification
 486  *
 487  * @cldev: bus device
 488  */
 489 static void mei_wdt_notify_event(struct mei_cl_device *cldev)
 490 {
 491         struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
 492
 493         if (wdt->state != MEI_WDT_NOT_REQUIRED)
 494                 return;
 495
 496         mei_wdt_register(wdt);
 497 }
 498
 499 /**
 500  * mei_wdt_event - callback for event receive
 501  *
 502  * @cldev: bus device
 503  * @events: event mask
 504  * @context: callback context
 505  */
 506 static void mei_wdt_event(struct mei_cl_device *cldev,
 507                           u32 events, void *context)
 508 {
 509         if (events & BIT(MEI_CL_EVENT_RX))
 510                 mei_wdt_event_rx(cldev);
 511
 512         if (events & BIT(MEI_CL_EVENT_NOTIF))
 513                 mei_wdt_notify_event(cldev);
 514 }
 515
 516 #if IS_ENABLED(CONFIG_DEBUG_FS)
 517
 518 static ssize_t mei_dbgfs_read_activation(struct file *file, char __user *ubuf,
 519                                         size_t cnt, loff_t *ppos)
 520 {
 521         struct mei_wdt *wdt = file->private_data;
 522         const size_t bufsz = 32;
 523         char buf[32];
 524         ssize_t pos;
 525
 526         mutex_lock(&wdt->reg_lock);
 527         pos = scnprintf(buf, bufsz, "%s\n",
 528                 __mei_wdt_is_registered(wdt) ? "activated" : "deactivated");
 529         mutex_unlock(&wdt->reg_lock);
 530
 531         return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
 532 }
 533
 534 static const struct file_operations dbgfs_fops_activation = {
 535         .open    = simple_open,
 536         .read    = mei_dbgfs_read_activation,
 537         .llseek  = generic_file_llseek,
 538 };
 539
 540 static ssize_t mei_dbgfs_read_state(struct file *file, char __user *ubuf,
 541                                     size_t cnt, loff_t *ppos)
 542 {
 543         struct mei_wdt *wdt = file->private_data;
 544         const size_t bufsz = 32;
 545         char buf[bufsz];
 546         ssize_t pos;
 547
 548         pos = scnprintf(buf, bufsz, "state: %s\n",
 549                          mei_wdt_state_str(wdt->state));
 550
 551         return simple_read_from_buffer(ubuf, cnt, ppos, buf, pos);
 552 }
 553
 554 static const struct file_operations dbgfs_fops_state = {
 555         .open = simple_open,
 556         .read = mei_dbgfs_read_state,
 557         .llseek = generic_file_llseek,
 558 };
 559
 560 static void dbgfs_unregister(struct mei_wdt *wdt)
 561 {
 562         debugfs_remove_recursive(wdt->dbgfs_dir);
 563         wdt->dbgfs_dir = NULL;
 564 }
 565
 566 static int dbgfs_register(struct mei_wdt *wdt)
 567 {
 568         struct dentry *dir, *f;
 569
 570         dir = debugfs_create_dir(KBUILD_MODNAME, NULL);
 571         if (!dir)
 572                 return -ENOMEM;
 573
 574         wdt->dbgfs_dir = dir;
 575         f = debugfs_create_file("state", S_IRUSR, dir, wdt, &dbgfs_fops_state);
 576         if (!f)
 577                 goto err;
 578
 579         f = debugfs_create_file("activation",  S_IRUSR,
 580                                 dir, wdt, &dbgfs_fops_activation);
 581         if (!f)
 582                 goto err;
 583
 584         return 0;
 585 err:
 586         dbgfs_unregister(wdt);
 587         return -ENODEV;
 588 }
 589
 590 #else
 591
 592 static inline void dbgfs_unregister(struct mei_wdt *wdt) {}
 593
 594 static inline int dbgfs_register(struct mei_wdt *wdt)
 595 {
 596         return 0;
 597 }
 598 #endif /* CONFIG_DEBUG_FS */
 599
 600 static int mei_wdt_probe(struct mei_cl_device *cldev,
 601                          const struct mei_cl_device_id *id)
 602 {
 603         struct mei_wdt *wdt;
 604         int ret;
 605
 606         wdt = kzalloc(sizeof(struct mei_wdt), GFP_KERNEL);
 607         if (!wdt)
 608                 return -ENOMEM;
 609
 610         wdt->timeout = MEI_WDT_DEFAULT_TIMEOUT;
 611         wdt->state = MEI_WDT_PROBE;
 612         wdt->cldev = cldev;
 613         wdt->resp_required = mei_cldev_ver(cldev) > 0x1;
 614         mutex_init(&wdt->reg_lock);
 615         init_completion(&wdt->response);
 616         INIT_WORK(&wdt->unregister, mei_wdt_unregister_work);
 617
 618         mei_cldev_set_drvdata(cldev, wdt);
 619
 620         ret = mei_cldev_enable(cldev);
 621         if (ret < 0) {
 622                 dev_err(&cldev->dev, "Could not enable cl device\n");
 623                 goto err_out;
 624         }
 625
 626         ret = mei_cldev_register_event_cb(wdt->cldev,
 627                                           BIT(MEI_CL_EVENT_RX) |
 628                                           BIT(MEI_CL_EVENT_NOTIF),
 629                                           mei_wdt_event, NULL);
 630
 631         /* on legacy devices notification is not supported
 632          * this doesn't fail the registration for RX event
 633          */
 634         if (ret && ret != -EOPNOTSUPP) {
 635                 dev_err(&cldev->dev, "Could not register event ret=%d\n", ret);
 636                 goto err_disable;
 637         }
 638
 639         wd_info.firmware_version = mei_cldev_ver(cldev);
 640
 641         if (wdt->resp_required)
 642                 ret = mei_wdt_ping(wdt);
 643         else
 644                 ret = mei_wdt_register(wdt);
 645
 646         if (ret)
 647                 goto err_disable;
 648
 649         if (dbgfs_register(wdt))
 650                 dev_warn(&cldev->dev, "cannot register debugfs\n");
 651
 652         return 0;
 653
 654 err_disable:
 655         mei_cldev_disable(cldev);
 656
 657 err_out:
 658         kfree(wdt);
 659
 660         return ret;
 661 }
 662
 663 static int mei_wdt_remove(struct mei_cl_device *cldev)
 664 {
 665         struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
 666
 667         /* Free the caller in case of fw initiated or unexpected reset */
 668         if (!completion_done(&wdt->response))
 669                 complete(&wdt->response);
 670
 671         cancel_work_sync(&wdt->unregister);
 672
 673         mei_wdt_unregister(wdt);
 674
 675         mei_cldev_disable(cldev);
 676
 677         dbgfs_unregister(wdt);
 678
 679         kfree(wdt);
 680
 681         return 0;
 682 }
 683
 684 #define MEI_UUID_WD UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, \
 685                             0x89, 0x9D, 0xA9, 0x15, 0x14, 0xCB, 0x32, 0xAB)
 686
 687 static struct mei_cl_device_id mei_wdt_tbl[] = {
 688         { .uuid = MEI_UUID_WD, .version = MEI_CL_VERSION_ANY },
 689         /* required last entry */
 690         { }
 691 };
 692 MODULE_DEVICE_TABLE(mei, mei_wdt_tbl);
 693
 694 static struct mei_cl_driver mei_wdt_driver = {
 695         .id_table = mei_wdt_tbl,
 696         .name = KBUILD_MODNAME,
 697
 698         .probe = mei_wdt_probe,
 699         .remove = mei_wdt_remove,
 700 };
 701
 702 static int __init mei_wdt_init(void)
 703 {
 704         int ret;
 705
 706         ret = mei_cldev_driver_register(&mei_wdt_driver);
 707         if (ret) {
 708                 pr_err(KBUILD_MODNAME ": module registration failed\n");
 709                 return ret;
 710         }
 711         return 0;
 712 }
 713
 714 static void __exit mei_wdt_exit(void)
 715 {
 716         mei_cldev_driver_unregister(&mei_wdt_driver);
 717 }
 718
 719 module_init(mei_wdt_init);
 720 module_exit(mei_wdt_exit);
 721
 722 MODULE_AUTHOR("Intel Corporation");
 723 MODULE_LICENSE("GPL");
 724 MODULE_DESCRIPTION("Device driver for Intel MEI iAMT watchdog");