drivers/misc/mei/main.c

   1 /*
   2  *
   3  * Intel Management Engine Interface (Intel MEI) Linux driver
   4  * Copyright (c) 2003-2012, Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  */
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/slab.h>
  21 #include <linux/fs.h>
  22 #include <linux/errno.h>
  23 #include <linux/types.h>
  24 #include <linux/fcntl.h>
  25 #include <linux/poll.h>
  26 #include <linux/init.h>
  27 #include <linux/ioctl.h>
  28 #include <linux/cdev.h>
  29 #include <linux/sched.h>
  30 #include <linux/uuid.h>
  31 #include <linux/compat.h>
  32 #include <linux/jiffies.h>
  33 #include <linux/interrupt.h>
  34
  35 #include <linux/mei.h>
  36
  37 #include "mei_dev.h"
  38 #include "client.h"
  39
  40 /**
  41  * mei_open - the open function
  42  *
  43  * @inode: pointer to inode structure
  44  * @file: pointer to file structure
  45  *
  46  * Return: 0 on success, <0 on error
  47  */
  48 static int mei_open(struct inode *inode, struct file *file)
  49 {
  50         struct mei_device *dev;
  51         struct mei_cl *cl;
  52
  53         int err;
  54
  55         dev = container_of(inode->i_cdev, struct mei_device, cdev);
  56         if (!dev)
  57                 return -ENODEV;
  58
  59         mutex_lock(&dev->device_lock);
  60
  61         if (dev->dev_state != MEI_DEV_ENABLED) {
  62                 dev_dbg(dev->dev, "dev_state != MEI_ENABLED  dev_state = %s\n",
  63                     mei_dev_state_str(dev->dev_state));
  64                 err = -ENODEV;
  65                 goto err_unlock;
  66         }
  67
  68         cl = mei_cl_alloc_linked(dev);
  69         if (IS_ERR(cl)) {
  70                 err = PTR_ERR(cl);
  71                 goto err_unlock;
  72         }
  73
  74         cl->fp = file;
  75         file->private_data = cl;
  76
  77         mutex_unlock(&dev->device_lock);
  78
  79         return nonseekable_open(inode, file);
  80
  81 err_unlock:
  82         mutex_unlock(&dev->device_lock);
  83         return err;
  84 }
  85
  86 /**
  87  * mei_release - the release function
  88  *
  89  * @inode: pointer to inode structure
  90  * @file: pointer to file structure
  91  *
  92  * Return: 0 on success, <0 on error
  93  */
  94 static int mei_release(struct inode *inode, struct file *file)
  95 {
  96         struct mei_cl *cl = file->private_data;
  97         struct mei_device *dev;
  98         int rets;
  99
 100         if (WARN_ON(!cl || !cl->dev))
 101                 return -ENODEV;
 102
 103         dev = cl->dev;
 104
 105         mutex_lock(&dev->device_lock);
 106         if (cl == &dev->iamthif_cl) {
 107                 rets = mei_amthif_release(dev, file);
 108                 goto out;
 109         }
 110         rets = mei_cl_disconnect(cl);
 111
 112         mei_cl_flush_queues(cl, file);
 113         cl_dbg(dev, cl, "removing\n");
 114
 115         mei_cl_unlink(cl);
 116
 117         file->private_data = NULL;
 118
 119         kfree(cl);
 120 out:
 121         mutex_unlock(&dev->device_lock);
 122         return rets;
 123 }
 124
 125
 126 /**
 127  * mei_read - the read function.
 128  *
 129  * @file: pointer to file structure
 130  * @ubuf: pointer to user buffer
 131  * @length: buffer length
 132  * @offset: data offset in buffer
 133  *
 134  * Return: >=0 data length on success , <0 on error
 135  */
 136 static ssize_t mei_read(struct file *file, char __user *ubuf,
 137                         size_t length, loff_t *offset)
 138 {
 139         struct mei_cl *cl = file->private_data;
 140         struct mei_device *dev;
 141         struct mei_cl_cb *cb = NULL;
 142         bool nonblock = !!(file->f_flags & O_NONBLOCK);
 143         int rets;
 144
 145         if (WARN_ON(!cl || !cl->dev))
 146                 return -ENODEV;
 147
 148         dev = cl->dev;
 149
 150
 151         mutex_lock(&dev->device_lock);
 152         if (dev->dev_state != MEI_DEV_ENABLED) {
 153                 rets = -ENODEV;
 154                 goto out;
 155         }
 156
 157         if (length == 0) {
 158                 rets = 0;
 159                 goto out;
 160         }
 161
 162         if (ubuf == NULL) {
 163                 rets = -EMSGSIZE;
 164                 goto out;
 165         }
 166
 167         cb = mei_cl_read_cb(cl, file);
 168         if (cb)
 169                 goto copy_buffer;
 170
 171         if (*offset > 0)
 172                 *offset = 0;
 173
 174         rets = mei_cl_read_start(cl, length, file);
 175         if (rets && rets != -EBUSY) {
 176                 cl_dbg(dev, cl, "mei start read failure status = %d\n", rets);
 177                 goto out;
 178         }
 179
 180         if (nonblock) {
 181                 rets = -EAGAIN;
 182                 goto out;
 183         }
 184
 185         if (rets == -EBUSY &&
 186             !mei_cl_enqueue_ctrl_wr_cb(cl, length, MEI_FOP_READ, file)) {
 187                 rets = -ENOMEM;
 188                 goto out;
 189         }
 190
 191         do {
 192                 mutex_unlock(&dev->device_lock);
 193
 194                 if (wait_event_interruptible(cl->rx_wait,
 195                                              (!list_empty(&cl->rd_completed)) ||
 196                                              (!mei_cl_is_connected(cl)))) {
 197
 198                         if (signal_pending(current))
 199                                 return -EINTR;
 200                         return -ERESTARTSYS;
 201                 }
 202
 203                 mutex_lock(&dev->device_lock);
 204                 if (!mei_cl_is_connected(cl)) {
 205                         rets = -ENODEV;
 206                         goto out;
 207                 }
 208
 209                 cb = mei_cl_read_cb(cl, file);
 210         } while (!cb);
 211
 212 copy_buffer:
 213         /* now copy the data to user space */
 214         if (cb->status) {
 215                 rets = cb->status;
 216                 cl_dbg(dev, cl, "read operation failed %d\n", rets);
 217                 goto free;
 218         }
 219
 220         cl_dbg(dev, cl, "buf.size = %zu buf.idx = %zu offset = %lld\n",
 221                cb->buf.size, cb->buf_idx, *offset);
 222         if (*offset >= cb->buf_idx) {
 223                 rets = 0;
 224                 goto free;
 225         }
 226
 227         /* length is being truncated to PAGE_SIZE,
 228          * however buf_idx may point beyond that */
 229         length = min_t(size_t, length, cb->buf_idx - *offset);
 230
 231         if (copy_to_user(ubuf, cb->buf.data + *offset, length)) {
 232                 dev_dbg(dev->dev, "failed to copy data to userland\n");
 233                 rets = -EFAULT;
 234                 goto free;
 235         }
 236
 237         rets = length;
 238         *offset += length;
 239         /* not all data was read, keep the cb */
 240         if (*offset < cb->buf_idx)
 241                 goto out;
 242
 243 free:
 244         mei_io_cb_free(cb);
 245         *offset = 0;
 246
 247 out:
 248         cl_dbg(dev, cl, "end mei read rets = %d\n", rets);
 249         mutex_unlock(&dev->device_lock);
 250         return rets;
 251 }
 252 /**
 253  * mei_write - the write function.
 254  *
 255  * @file: pointer to file structure
 256  * @ubuf: pointer to user buffer
 257  * @length: buffer length
 258  * @offset: data offset in buffer
 259  *
 260  * Return: >=0 data length on success , <0 on error
 261  */
 262 static ssize_t mei_write(struct file *file, const char __user *ubuf,
 263                          size_t length, loff_t *offset)
 264 {
 265         struct mei_cl *cl = file->private_data;
 266         struct mei_cl_cb *cb;
 267         struct mei_device *dev;
 268         int rets;
 269
 270         if (WARN_ON(!cl || !cl->dev))
 271                 return -ENODEV;
 272
 273         dev = cl->dev;
 274
 275         mutex_lock(&dev->device_lock);
 276
 277         if (dev->dev_state != MEI_DEV_ENABLED) {
 278                 rets = -ENODEV;
 279                 goto out;
 280         }
 281
 282         if (!mei_cl_is_connected(cl)) {
 283                 cl_err(dev, cl, "is not connected");
 284                 rets = -ENODEV;
 285                 goto out;
 286         }
 287
 288         if (!mei_me_cl_is_active(cl->me_cl)) {
 289                 rets = -ENOTTY;
 290                 goto out;
 291         }
 292
 293         if (length > mei_cl_mtu(cl)) {
 294                 rets = -EFBIG;
 295                 goto out;
 296         }
 297
 298         if (length == 0) {
 299                 rets = 0;
 300                 goto out;
 301         }
 302
 303         *offset = 0;
 304         cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, file);
 305         if (!cb) {
 306                 rets = -ENOMEM;
 307                 goto out;
 308         }
 309
 310         rets = copy_from_user(cb->buf.data, ubuf, length);
 311         if (rets) {
 312                 dev_dbg(dev->dev, "failed to copy data from userland\n");
 313                 rets = -EFAULT;
 314                 mei_io_cb_free(cb);
 315                 goto out;
 316         }
 317
 318         if (cl == &dev->iamthif_cl) {
 319                 rets = mei_amthif_write(cl, cb);
 320                 if (!rets)
 321                         rets = length;
 322                 goto out;
 323         }
 324
 325         rets = mei_cl_write(cl, cb, false);
 326 out:
 327         mutex_unlock(&dev->device_lock);
 328         return rets;
 329 }
 330
 331 /**
 332  * mei_ioctl_connect_client - the connect to fw client IOCTL function
 333  *
 334  * @file: private data of the file object
 335  * @data: IOCTL connect data, input and output parameters
 336  *
 337  * Locking: called under "dev->device_lock" lock
 338  *
 339  * Return: 0 on success, <0 on failure.
 340  */
 341 static int mei_ioctl_connect_client(struct file *file,
 342                         struct mei_connect_client_data *data)
 343 {
 344         struct mei_device *dev;
 345         struct mei_client *client;
 346         struct mei_me_client *me_cl;
 347         struct mei_cl *cl;
 348         int rets;
 349
 350         cl = file->private_data;
 351         dev = cl->dev;
 352
 353         if (dev->dev_state != MEI_DEV_ENABLED)
 354                 return -ENODEV;
 355
 356         if (cl->state != MEI_FILE_INITIALIZING &&
 357             cl->state != MEI_FILE_DISCONNECTED)
 358                 return  -EBUSY;
 359
 360         /* find ME client we're trying to connect to */
 361         me_cl = mei_me_cl_by_uuid(dev, &data->in_client_uuid);
 362         if (!me_cl) {
 363                 dev_dbg(dev->dev, "Cannot connect to FW Client UUID = %pUl\n",
 364                         &data->in_client_uuid);
 365                 rets = -ENOTTY;
 366                 goto end;
 367         }
 368
 369         if (me_cl->props.fixed_address) {
 370                 bool forbidden = dev->override_fixed_address ?
 371                          !dev->allow_fixed_address : !dev->hbm_f_fa_supported;
 372                 if (forbidden) {
 373                         dev_dbg(dev->dev, "Connection forbidden to FW Client UUID = %pUl\n",
 374                                 &data->in_client_uuid);
 375                         rets = -ENOTTY;
 376                         goto end;
 377                 }
 378         }
 379
 380         dev_dbg(dev->dev, "Connect to FW Client ID = %d\n",
 381                         me_cl->client_id);
 382         dev_dbg(dev->dev, "FW Client - Protocol Version = %d\n",
 383                         me_cl->props.protocol_version);
 384         dev_dbg(dev->dev, "FW Client - Max Msg Len = %d\n",
 385                         me_cl->props.max_msg_length);
 386
 387         /* if we're connecting to amthif client then we will use the
 388          * existing connection
 389          */
 390         if (uuid_le_cmp(data->in_client_uuid, mei_amthif_guid) == 0) {
 391                 dev_dbg(dev->dev, "FW Client is amthi\n");
 392                 if (!mei_cl_is_connected(&dev->iamthif_cl)) {
 393                         rets = -ENODEV;
 394                         goto end;
 395                 }
 396                 mei_cl_unlink(cl);
 397
 398                 kfree(cl);
 399                 cl = NULL;
 400                 dev->iamthif_open_count++;
 401                 file->private_data = &dev->iamthif_cl;
 402
 403                 client = &data->out_client_properties;
 404                 client->max_msg_length = me_cl->props.max_msg_length;
 405                 client->protocol_version = me_cl->props.protocol_version;
 406                 rets = dev->iamthif_cl.status;
 407
 408                 goto end;
 409         }
 410
 411         /* prepare the output buffer */
 412         client = &data->out_client_properties;
 413         client->max_msg_length = me_cl->props.max_msg_length;
 414         client->protocol_version = me_cl->props.protocol_version;
 415         dev_dbg(dev->dev, "Can connect?\n");
 416
 417         rets = mei_cl_connect(cl, me_cl, file);
 418
 419 end:
 420         mei_me_cl_put(me_cl);
 421         return rets;
 422 }
 423
 424 /**
 425  * mei_ioctl_client_notify_request -
 426  *     propagate event notification request to client
 427  *
 428  * @file: pointer to file structure
 429  * @request: 0 - disable, 1 - enable
 430  *
 431  * Return: 0 on success , <0 on error
 432  */
 433 static int mei_ioctl_client_notify_request(const struct file *file, u32 request)
 434 {
 435         struct mei_cl *cl = file->private_data;
 436
 437         if (request != MEI_HBM_NOTIFICATION_START &&
 438             request != MEI_HBM_NOTIFICATION_STOP)
 439                 return -EINVAL;
 440
 441         return mei_cl_notify_request(cl, file, (u8)request);
 442 }
 443
 444 /**
 445  * mei_ioctl_client_notify_get -  wait for notification request
 446  *
 447  * @file: pointer to file structure
 448  * @notify_get: 0 - disable, 1 - enable
 449  *
 450  * Return: 0 on success , <0 on error
 451  */
 452 static int mei_ioctl_client_notify_get(const struct file *file, u32 *notify_get)
 453 {
 454         struct mei_cl *cl = file->private_data;
 455         bool notify_ev;
 456         bool block = (file->f_flags & O_NONBLOCK) == 0;
 457         int rets;
 458
 459         rets = mei_cl_notify_get(cl, block, &notify_ev);
 460         if (rets)
 461                 return rets;
 462
 463         *notify_get = notify_ev ? 1 : 0;
 464         return 0;
 465 }
 466
 467 /**
 468  * mei_ioctl - the IOCTL function
 469  *
 470  * @file: pointer to file structure
 471  * @cmd: ioctl command
 472  * @data: pointer to mei message structure
 473  *
 474  * Return: 0 on success , <0 on error
 475  */
 476 static long mei_ioctl(struct file *file, unsigned int cmd, unsigned long data)
 477 {
 478         struct mei_device *dev;
 479         struct mei_cl *cl = file->private_data;
 480         struct mei_connect_client_data connect_data;
 481         u32 notify_get, notify_req;
 482         int rets;
 483
 484
 485         if (WARN_ON(!cl || !cl->dev))
 486                 return -ENODEV;
 487
 488         dev = cl->dev;
 489
 490         dev_dbg(dev->dev, "IOCTL cmd = 0x%x", cmd);
 491
 492         mutex_lock(&dev->device_lock);
 493         if (dev->dev_state != MEI_DEV_ENABLED) {
 494                 rets = -ENODEV;
 495                 goto out;
 496         }
 497
 498         switch (cmd) {
 499         case IOCTL_MEI_CONNECT_CLIENT:
 500                 dev_dbg(dev->dev, ": IOCTL_MEI_CONNECT_CLIENT.\n");
 501                 if (copy_from_user(&connect_data, (char __user *)data,
 502                                 sizeof(struct mei_connect_client_data))) {
 503                         dev_dbg(dev->dev, "failed to copy data from userland\n");
 504                         rets = -EFAULT;
 505                         goto out;
 506                 }
 507
 508                 rets = mei_ioctl_connect_client(file, &connect_data);
 509                 if (rets)
 510                         goto out;
 511
 512                 /* if all is ok, copying the data back to user. */
 513                 if (copy_to_user((char __user *)data, &connect_data,
 514                                 sizeof(struct mei_connect_client_data))) {
 515                         dev_dbg(dev->dev, "failed to copy data to userland\n");
 516                         rets = -EFAULT;
 517                         goto out;
 518                 }
 519
 520                 break;
 521
 522         case IOCTL_MEI_NOTIFY_SET:
 523                 dev_dbg(dev->dev, ": IOCTL_MEI_NOTIFY_SET.\n");
 524                 if (copy_from_user(&notify_req,
 525                                    (char __user *)data, sizeof(notify_req))) {
 526                         dev_dbg(dev->dev, "failed to copy data from userland\n");
 527                         rets = -EFAULT;
 528                         goto out;
 529                 }
 530                 rets = mei_ioctl_client_notify_request(file, notify_req);
 531                 break;
 532
 533         case IOCTL_MEI_NOTIFY_GET:
 534                 dev_dbg(dev->dev, ": IOCTL_MEI_NOTIFY_GET.\n");
 535                 rets = mei_ioctl_client_notify_get(file, &notify_get);
 536                 if (rets)
 537                         goto out;
 538
 539                 dev_dbg(dev->dev, "copy connect data to user\n");
 540                 if (copy_to_user((char __user *)data,
 541                                 &notify_get, sizeof(notify_get))) {
 542                         dev_dbg(dev->dev, "failed to copy data to userland\n");
 543                         rets = -EFAULT;
 544                         goto out;
 545
 546                 }
 547                 break;
 548
 549         default:
 550                 dev_err(dev->dev, ": unsupported ioctl %d.\n", cmd);
 551                 rets = -ENOIOCTLCMD;
 552         }
 553
 554 out:
 555         mutex_unlock(&dev->device_lock);
 556         return rets;
 557 }
 558
 559 /**
 560  * mei_compat_ioctl - the compat IOCTL function
 561  *
 562  * @file: pointer to file structure
 563  * @cmd: ioctl command
 564  * @data: pointer to mei message structure
 565  *
 566  * Return: 0 on success , <0 on error
 567  */
 568 #ifdef CONFIG_COMPAT
 569 static long mei_compat_ioctl(struct file *file,
 570                         unsigned int cmd, unsigned long data)
 571 {
 572         return mei_ioctl(file, cmd, (unsigned long)compat_ptr(data));
 573 }
 574 #endif
 575
 576
 577 /**
 578  * mei_poll - the poll function
 579  *
 580  * @file: pointer to file structure
 581  * @wait: pointer to poll_table structure
 582  *
 583  * Return: poll mask
 584  */
 585 static unsigned int mei_poll(struct file *file, poll_table *wait)
 586 {
 587         unsigned long req_events = poll_requested_events(wait);
 588         struct mei_cl *cl = file->private_data;
 589         struct mei_device *dev;
 590         unsigned int mask = 0;
 591         bool notify_en;
 592
 593         if (WARN_ON(!cl || !cl->dev))
 594                 return POLLERR;
 595
 596         dev = cl->dev;
 597
 598         mutex_lock(&dev->device_lock);
 599
 600         notify_en = cl->notify_en && (req_events & POLLPRI);
 601
 602         if (dev->dev_state != MEI_DEV_ENABLED ||
 603             !mei_cl_is_connected(cl)) {
 604                 mask = POLLERR;
 605                 goto out;
 606         }
 607
 608         if (notify_en) {
 609                 poll_wait(file, &cl->ev_wait, wait);
 610                 if (cl->notify_ev)
 611                         mask |= POLLPRI;
 612         }
 613
 614         if (cl == &dev->iamthif_cl) {
 615                 mask |= mei_amthif_poll(file, wait);
 616                 goto out;
 617         }
 618
 619         if (req_events & (POLLIN | POLLRDNORM)) {
 620                 poll_wait(file, &cl->rx_wait, wait);
 621
 622                 if (!list_empty(&cl->rd_completed))
 623                         mask |= POLLIN | POLLRDNORM;
 624                 else
 625                         mei_cl_read_start(cl, mei_cl_mtu(cl), file);
 626         }
 627
 628 out:
 629         mutex_unlock(&dev->device_lock);
 630         return mask;
 631 }
 632
 633 /**
 634  * mei_fasync - asynchronous io support
 635  *
 636  * @fd: file descriptor
 637  * @file: pointer to file structure
 638  * @band: band bitmap
 639  *
 640  * Return: negative on error,
 641  *         0 if it did no changes,
 642  *         and positive a process was added or deleted
 643  */
 644 static int mei_fasync(int fd, struct file *file, int band)
 645 {
 646
 647         struct mei_cl *cl = file->private_data;
 648
 649         if (!mei_cl_is_connected(cl))
 650                 return -ENODEV;
 651
 652         return fasync_helper(fd, file, band, &cl->ev_async);
 653 }
 654
 655 /**
 656  * fw_status_show - mei device attribute show method
 657  *
 658  * @device: device pointer
 659  * @attr: attribute pointer
 660  * @buf:  char out buffer
 661  *
 662  * Return: number of the bytes printed into buf or error
 663  */
 664 static ssize_t fw_status_show(struct device *device,
 665                 struct device_attribute *attr, char *buf)
 666 {
 667         struct mei_device *dev = dev_get_drvdata(device);
 668         struct mei_fw_status fw_status;
 669         int err, i;
 670         ssize_t cnt = 0;
 671
 672         mutex_lock(&dev->device_lock);
 673         err = mei_fw_status(dev, &fw_status);
 674         mutex_unlock(&dev->device_lock);
 675         if (err) {
 676                 dev_err(device, "read fw_status error = %d\n", err);
 677                 return err;
 678         }
 679
 680         for (i = 0; i < fw_status.count; i++)
 681                 cnt += scnprintf(buf + cnt, PAGE_SIZE - cnt, "%08X\n",
 682                                 fw_status.status[i]);
 683         return cnt;
 684 }
 685 static DEVICE_ATTR_RO(fw_status);
 686
 687 static struct attribute *mei_attrs[] = {
 688         &dev_attr_fw_status.attr,
 689         NULL
 690 };
 691 ATTRIBUTE_GROUPS(mei);
 692
 693 /*
 694  * file operations structure will be used for mei char device.
 695  */
 696 static const struct file_operations mei_fops = {
 697         .owner = THIS_MODULE,
 698         .read = mei_read,
 699         .unlocked_ioctl = mei_ioctl,
 700 #ifdef CONFIG_COMPAT
 701         .compat_ioctl = mei_compat_ioctl,
 702 #endif
 703         .open = mei_open,
 704         .release = mei_release,
 705         .write = mei_write,
 706         .poll = mei_poll,
 707         .fasync = mei_fasync,
 708         .llseek = no_llseek
 709 };
 710
 711 static struct class *mei_class;
 712 static dev_t mei_devt;
 713 #define MEI_MAX_DEVS  MINORMASK
 714 static DEFINE_MUTEX(mei_minor_lock);
 715 static DEFINE_IDR(mei_idr);
 716
 717 /**
 718  * mei_minor_get - obtain next free device minor number
 719  *
 720  * @dev:  device pointer
 721  *
 722  * Return: allocated minor, or -ENOSPC if no free minor left
 723  */
 724 static int mei_minor_get(struct mei_device *dev)
 725 {
 726         int ret;
 727
 728         mutex_lock(&mei_minor_lock);
 729         ret = idr_alloc(&mei_idr, dev, 0, MEI_MAX_DEVS, GFP_KERNEL);
 730         if (ret >= 0)
 731                 dev->minor = ret;
 732         else if (ret == -ENOSPC)
 733                 dev_err(dev->dev, "too many mei devices\n");
 734
 735         mutex_unlock(&mei_minor_lock);
 736         return ret;
 737 }
 738
 739 /**
 740  * mei_minor_free - mark device minor number as free
 741  *
 742  * @dev:  device pointer
 743  */
 744 static void mei_minor_free(struct mei_device *dev)
 745 {
 746         mutex_lock(&mei_minor_lock);
 747         idr_remove(&mei_idr, dev->minor);
 748         mutex_unlock(&mei_minor_lock);
 749 }
 750
 751 int mei_register(struct mei_device *dev, struct device *parent)
 752 {
 753         struct device *clsdev; /* class device */
 754         int ret, devno;
 755
 756         ret = mei_minor_get(dev);
 757         if (ret < 0)
 758                 return ret;
 759
 760         /* Fill in the data structures */
 761         devno = MKDEV(MAJOR(mei_devt), dev->minor);
 762         cdev_init(&dev->cdev, &mei_fops);
 763         dev->cdev.owner = parent->driver->owner;
 764
 765         /* Add the device */
 766         ret = cdev_add(&dev->cdev, devno, 1);
 767         if (ret) {
 768                 dev_err(parent, "unable to add device %d:%d\n",
 769                         MAJOR(mei_devt), dev->minor);
 770                 goto err_dev_add;
 771         }
 772
 773         clsdev = device_create_with_groups(mei_class, parent, devno,
 774                                            dev, mei_groups,
 775                                            "mei%d", dev->minor);
 776
 777         if (IS_ERR(clsdev)) {
 778                 dev_err(parent, "unable to create device %d:%d\n",
 779                         MAJOR(mei_devt), dev->minor);
 780                 ret = PTR_ERR(clsdev);
 781                 goto err_dev_create;
 782         }
 783
 784         ret = mei_dbgfs_register(dev, dev_name(clsdev));
 785         if (ret) {
 786                 dev_err(clsdev, "cannot register debugfs ret = %d\n", ret);
 787                 goto err_dev_dbgfs;
 788         }
 789
 790         return 0;
 791
 792 err_dev_dbgfs:
 793         device_destroy(mei_class, devno);
 794 err_dev_create:
 795         cdev_del(&dev->cdev);
 796 err_dev_add:
 797         mei_minor_free(dev);
 798         return ret;
 799 }
 800 EXPORT_SYMBOL_GPL(mei_register);
 801
 802 void mei_deregister(struct mei_device *dev)
 803 {
 804         int devno;
 805
 806         devno = dev->cdev.dev;
 807         cdev_del(&dev->cdev);
 808
 809         mei_dbgfs_deregister(dev);
 810
 811         device_destroy(mei_class, devno);
 812
 813         mei_minor_free(dev);
 814 }
 815 EXPORT_SYMBOL_GPL(mei_deregister);
 816
 817 static int __init mei_init(void)
 818 {
 819         int ret;
 820
 821         mei_class = class_create(THIS_MODULE, "mei");
 822         if (IS_ERR(mei_class)) {
 823                 pr_err("couldn't create class\n");
 824                 ret = PTR_ERR(mei_class);
 825                 goto err;
 826         }
 827
 828         ret = alloc_chrdev_region(&mei_devt, 0, MEI_MAX_DEVS, "mei");
 829         if (ret < 0) {
 830                 pr_err("unable to allocate char dev region\n");
 831                 goto err_class;
 832         }
 833
 834         ret = mei_cl_bus_init();
 835         if (ret < 0) {
 836                 pr_err("unable to initialize bus\n");
 837                 goto err_chrdev;
 838         }
 839
 840         return 0;
 841
 842 err_chrdev:
 843         unregister_chrdev_region(mei_devt, MEI_MAX_DEVS);
 844 err_class:
 845         class_destroy(mei_class);
 846 err:
 847         return ret;
 848 }
 849
 850 static void __exit mei_exit(void)
 851 {
 852         unregister_chrdev_region(mei_devt, MEI_MAX_DEVS);
 853         class_destroy(mei_class);
 854         mei_cl_bus_exit();
 855 }
 856
 857 module_init(mei_init);
 858 module_exit(mei_exit);
 859
 860 MODULE_AUTHOR("Intel Corporation");
 861 MODULE_DESCRIPTION("Intel(R) Management Engine Interface");
 862 MODULE_LICENSE("GPL v2");
 863