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, MEI_HOST_CLIENT_ID_ANY);
  69         if (IS_ERR(cl)) {
  70                 err = PTR_ERR(cl);
  71                 goto err_unlock;
  72         }
  73
  74         file->private_data = cl;
  75
  76         mutex_unlock(&dev->device_lock);
  77
  78         return nonseekable_open(inode, file);
  79
  80 err_unlock:
  81         mutex_unlock(&dev->device_lock);
  82         return err;
  83 }
  84
  85 /**
  86  * mei_release - the release function
  87  *
  88  * @inode: pointer to inode structure
  89  * @file: pointer to file structure
  90  *
  91  * Return: 0 on success, <0 on error
  92  */
  93 static int mei_release(struct inode *inode, struct file *file)
  94 {
  95         struct mei_cl *cl = file->private_data;
  96         struct mei_device *dev;
  97         int rets;
  98
  99         if (WARN_ON(!cl || !cl->dev))
 100                 return -ENODEV;
 101
 102         dev = cl->dev;
 103
 104         mutex_lock(&dev->device_lock);
 105         if (cl == &dev->iamthif_cl) {
 106                 rets = mei_amthif_release(dev, file);
 107                 goto out;
 108         }
 109         rets = mei_cl_disconnect(cl);
 110
 111         mei_cl_flush_queues(cl, file);
 112         cl_dbg(dev, cl, "removing\n");
 113
 114         mei_cl_unlink(cl);
 115
 116         file->private_data = NULL;
 117
 118         kfree(cl);
 119 out:
 120         mutex_unlock(&dev->device_lock);
 121         return rets;
 122 }
 123
 124
 125 /**
 126  * mei_read - the read function.
 127  *
 128  * @file: pointer to file structure
 129  * @ubuf: pointer to user buffer
 130  * @length: buffer length
 131  * @offset: data offset in buffer
 132  *
 133  * Return: >=0 data length on success , <0 on error
 134  */
 135 static ssize_t mei_read(struct file *file, char __user *ubuf,
 136                         size_t length, loff_t *offset)
 137 {
 138         struct mei_cl *cl = file->private_data;
 139         struct mei_device *dev;
 140         struct mei_cl_cb *cb = NULL;
 141         int rets;
 142         int err;
 143
 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 (cl == &dev->iamthif_cl) {
 163                 rets = mei_amthif_read(dev, file, ubuf, length, offset);
 164                 goto out;
 165         }
 166
 167         cb = mei_cl_read_cb(cl, file);
 168         if (cb) {
 169                 /* read what left */
 170                 if (cb->buf_idx > *offset)
 171                         goto copy_buffer;
 172                 /* offset is beyond buf_idx we have no more data return 0 */
 173                 if (cb->buf_idx > 0 && cb->buf_idx <= *offset) {
 174                         rets = 0;
 175                         goto free;
 176                 }
 177                 /* Offset needs to be cleaned for contiguous reads*/
 178                 if (cb->buf_idx == 0 && *offset > 0)
 179                         *offset = 0;
 180         } else if (*offset > 0) {
 181                 *offset = 0;
 182         }
 183
 184         err = mei_cl_read_start(cl, length, file);
 185         if (err && err != -EBUSY) {
 186                 cl_dbg(dev, cl, "mei start read failure status = %d\n", err);
 187                 rets = err;
 188                 goto out;
 189         }
 190
 191         if (list_empty(&cl->rd_completed) && !waitqueue_active(&cl->rx_wait)) {
 192                 if (file->f_flags & O_NONBLOCK) {
 193                         rets = -EAGAIN;
 194                         goto out;
 195                 }
 196
 197                 mutex_unlock(&dev->device_lock);
 198
 199                 if (wait_event_interruptible(cl->rx_wait,
 200                                 (!list_empty(&cl->rd_completed)) ||
 201                                 (!mei_cl_is_connected(cl)))) {
 202
 203                         if (signal_pending(current))
 204                                 return -EINTR;
 205                         return -ERESTARTSYS;
 206                 }
 207
 208                 mutex_lock(&dev->device_lock);
 209                 if (!mei_cl_is_connected(cl)) {
 210                         rets = -ENODEV;
 211                         goto out;
 212                 }
 213         }
 214
 215         cb = mei_cl_read_cb(cl, file);
 216         if (!cb) {
 217                 if (mei_cl_is_fixed_address(cl) && dev->allow_fixed_address) {
 218                         cb = mei_cl_read_cb(cl, NULL);
 219                         if (cb)
 220                                 goto copy_buffer;
 221                 }
 222                 rets = 0;
 223                 goto out;
 224         }
 225
 226 copy_buffer:
 227         /* now copy the data to user space */
 228         if (cb->status) {
 229                 rets = cb->status;
 230                 cl_dbg(dev, cl, "read operation failed %d\n", rets);
 231                 goto free;
 232         }
 233
 234         cl_dbg(dev, cl, "buf.size = %d buf.idx = %ld\n",
 235             cb->buf.size, cb->buf_idx);
 236         if (length == 0 || ubuf == NULL || *offset > cb->buf_idx) {
 237                 rets = -EMSGSIZE;
 238                 goto free;
 239         }
 240
 241         /* length is being truncated to PAGE_SIZE,
 242          * however buf_idx may point beyond that */
 243         length = min_t(size_t, length, cb->buf_idx - *offset);
 244
 245         if (copy_to_user(ubuf, cb->buf.data + *offset, length)) {
 246                 dev_dbg(dev->dev, "failed to copy data to userland\n");
 247                 rets = -EFAULT;
 248                 goto free;
 249         }
 250
 251         rets = length;
 252         *offset += length;
 253         if ((unsigned long)*offset < cb->buf_idx)
 254                 goto out;
 255
 256 free:
 257         mei_io_cb_free(cb);
 258
 259 out:
 260         cl_dbg(dev, cl, "end mei read rets = %d\n", rets);
 261         mutex_unlock(&dev->device_lock);
 262         return rets;
 263 }
 264 /**
 265  * mei_write - the write function.
 266  *
 267  * @file: pointer to file structure
 268  * @ubuf: pointer to user buffer
 269  * @length: buffer length
 270  * @offset: data offset in buffer
 271  *
 272  * Return: >=0 data length on success , <0 on error
 273  */
 274 static ssize_t mei_write(struct file *file, const char __user *ubuf,
 275                          size_t length, loff_t *offset)
 276 {
 277         struct mei_cl *cl = file->private_data;
 278         struct mei_cl_cb *write_cb = NULL;
 279         struct mei_device *dev;
 280         unsigned long timeout = 0;
 281         int rets;
 282
 283         if (WARN_ON(!cl || !cl->dev))
 284                 return -ENODEV;
 285
 286         dev = cl->dev;
 287
 288         mutex_lock(&dev->device_lock);
 289
 290         if (dev->dev_state != MEI_DEV_ENABLED) {
 291                 rets = -ENODEV;
 292                 goto out;
 293         }
 294
 295         if (!mei_cl_is_connected(cl)) {
 296                 cl_err(dev, cl, "is not connected");
 297                 rets = -ENODEV;
 298                 goto out;
 299         }
 300
 301         if (!mei_me_cl_is_active(cl->me_cl)) {
 302                 rets = -ENOTTY;
 303                 goto out;
 304         }
 305
 306         if (length > mei_cl_mtu(cl)) {
 307                 rets = -EFBIG;
 308                 goto out;
 309         }
 310
 311         if (length == 0) {
 312                 rets = 0;
 313                 goto out;
 314         }
 315
 316         if (cl == &dev->iamthif_cl) {
 317                 write_cb = mei_amthif_find_read_list_entry(dev, file);
 318
 319                 if (write_cb) {
 320                         timeout = write_cb->read_time +
 321                                 mei_secs_to_jiffies(MEI_IAMTHIF_READ_TIMER);
 322
 323                         if (time_after(jiffies, timeout)) {
 324                                 *offset = 0;
 325                                 mei_io_cb_free(write_cb);
 326                                 write_cb = NULL;
 327                         }
 328                 }
 329         }
 330
 331         *offset = 0;
 332         write_cb = mei_cl_alloc_cb(cl, length, MEI_FOP_WRITE, file);
 333         if (!write_cb) {
 334                 rets = -ENOMEM;
 335                 goto out;
 336         }
 337
 338         rets = copy_from_user(write_cb->buf.data, ubuf, length);
 339         if (rets) {
 340                 dev_dbg(dev->dev, "failed to copy data from userland\n");
 341                 rets = -EFAULT;
 342                 goto out;
 343         }
 344
 345         if (cl == &dev->iamthif_cl) {
 346                 rets = mei_amthif_write(cl, write_cb);
 347
 348                 if (rets) {
 349                         dev_err(dev->dev,
 350                                 "amthif write failed with status = %d\n", rets);
 351                         goto out;
 352                 }
 353                 mutex_unlock(&dev->device_lock);
 354                 return length;
 355         }
 356
 357         rets = mei_cl_write(cl, write_cb, false);
 358 out:
 359         mutex_unlock(&dev->device_lock);
 360         if (rets < 0)
 361                 mei_io_cb_free(write_cb);
 362         return rets;
 363 }
 364
 365 /**
 366  * mei_ioctl_connect_client - the connect to fw client IOCTL function
 367  *
 368  * @file: private data of the file object
 369  * @data: IOCTL connect data, input and output parameters
 370  *
 371  * Locking: called under "dev->device_lock" lock
 372  *
 373  * Return: 0 on success, <0 on failure.
 374  */
 375 static int mei_ioctl_connect_client(struct file *file,
 376                         struct mei_connect_client_data *data)
 377 {
 378         struct mei_device *dev;
 379         struct mei_client *client;
 380         struct mei_me_client *me_cl;
 381         struct mei_cl *cl;
 382         int rets;
 383
 384         cl = file->private_data;
 385         dev = cl->dev;
 386
 387         if (dev->dev_state != MEI_DEV_ENABLED)
 388                 return -ENODEV;
 389
 390         if (cl->state != MEI_FILE_INITIALIZING &&
 391             cl->state != MEI_FILE_DISCONNECTED)
 392                 return  -EBUSY;
 393
 394         /* find ME client we're trying to connect to */
 395         me_cl = mei_me_cl_by_uuid(dev, &data->in_client_uuid);
 396         if (!me_cl ||
 397             (me_cl->props.fixed_address && !dev->allow_fixed_address)) {
 398                 dev_dbg(dev->dev, "Cannot connect to FW Client UUID = %pUl\n",
 399                         &data->in_client_uuid);
 400                 mei_me_cl_put(me_cl);
 401                 return  -ENOTTY;
 402         }
 403
 404         dev_dbg(dev->dev, "Connect to FW Client ID = %d\n",
 405                         me_cl->client_id);
 406         dev_dbg(dev->dev, "FW Client - Protocol Version = %d\n",
 407                         me_cl->props.protocol_version);
 408         dev_dbg(dev->dev, "FW Client - Max Msg Len = %d\n",
 409                         me_cl->props.max_msg_length);
 410
 411         /* if we're connecting to amthif client then we will use the
 412          * existing connection
 413          */
 414         if (uuid_le_cmp(data->in_client_uuid, mei_amthif_guid) == 0) {
 415                 dev_dbg(dev->dev, "FW Client is amthi\n");
 416                 if (!mei_cl_is_connected(&dev->iamthif_cl)) {
 417                         rets = -ENODEV;
 418                         goto end;
 419                 }
 420                 mei_cl_unlink(cl);
 421
 422                 kfree(cl);
 423                 cl = NULL;
 424                 dev->iamthif_open_count++;
 425                 file->private_data = &dev->iamthif_cl;
 426
 427                 client = &data->out_client_properties;
 428                 client->max_msg_length = me_cl->props.max_msg_length;
 429                 client->protocol_version = me_cl->props.protocol_version;
 430                 rets = dev->iamthif_cl.status;
 431
 432                 goto end;
 433         }
 434
 435         /* prepare the output buffer */
 436         client = &data->out_client_properties;
 437         client->max_msg_length = me_cl->props.max_msg_length;
 438         client->protocol_version = me_cl->props.protocol_version;
 439         dev_dbg(dev->dev, "Can connect?\n");
 440
 441         rets = mei_cl_connect(cl, me_cl, file);
 442
 443 end:
 444         mei_me_cl_put(me_cl);
 445         return rets;
 446 }
 447
 448 /**
 449  * mei_ioctl_client_notify_request -
 450  *     propagate event notification request to client
 451  *
 452  * @file: pointer to file structure
 453  * @request: 0 - disable, 1 - enable
 454  *
 455  * Return: 0 on success , <0 on error
 456  */
 457 static int mei_ioctl_client_notify_request(struct file *file, u32 request)
 458 {
 459         struct mei_cl *cl = file->private_data;
 460
 461         if (request != MEI_HBM_NOTIFICATION_START &&
 462             request != MEI_HBM_NOTIFICATION_STOP)
 463                 return -EINVAL;
 464
 465         return mei_cl_notify_request(cl, file, (u8)request);
 466 }
 467
 468 /**
 469  * mei_ioctl_client_notify_get -  wait for notification request
 470  *
 471  * @file: pointer to file structure
 472  * @notify_get: 0 - disable, 1 - enable
 473  *
 474  * Return: 0 on success , <0 on error
 475  */
 476 static int mei_ioctl_client_notify_get(struct file *file, u32 *notify_get)
 477 {
 478         struct mei_cl *cl = file->private_data;
 479         bool notify_ev;
 480         bool block = (file->f_flags & O_NONBLOCK) == 0;
 481         int rets;
 482
 483         rets = mei_cl_notify_get(cl, block, &notify_ev);
 484         if (rets)
 485                 return rets;
 486
 487         *notify_get = notify_ev ? 1 : 0;
 488         return 0;
 489 }
 490
 491 /**
 492  * mei_ioctl - the IOCTL function
 493  *
 494  * @file: pointer to file structure
 495  * @cmd: ioctl command
 496  * @data: pointer to mei message structure
 497  *
 498  * Return: 0 on success , <0 on error
 499  */
 500 static long mei_ioctl(struct file *file, unsigned int cmd, unsigned long data)
 501 {
 502         struct mei_device *dev;
 503         struct mei_cl *cl = file->private_data;
 504         struct mei_connect_client_data connect_data;
 505         u32 notify_get, notify_req;
 506         int rets;
 507
 508
 509         if (WARN_ON(!cl || !cl->dev))
 510                 return -ENODEV;
 511
 512         dev = cl->dev;
 513
 514         dev_dbg(dev->dev, "IOCTL cmd = 0x%x", cmd);
 515
 516         mutex_lock(&dev->device_lock);
 517         if (dev->dev_state != MEI_DEV_ENABLED) {
 518                 rets = -ENODEV;
 519                 goto out;
 520         }
 521
 522         switch (cmd) {
 523         case IOCTL_MEI_CONNECT_CLIENT:
 524                 dev_dbg(dev->dev, ": IOCTL_MEI_CONNECT_CLIENT.\n");
 525                 if (copy_from_user(&connect_data, (char __user *)data,
 526                                 sizeof(struct mei_connect_client_data))) {
 527                         dev_dbg(dev->dev, "failed to copy data from userland\n");
 528                         rets = -EFAULT;
 529                         goto out;
 530                 }
 531
 532                 rets = mei_ioctl_connect_client(file, &connect_data);
 533                 if (rets)
 534                         goto out;
 535
 536                 /* if all is ok, copying the data back to user. */
 537                 if (copy_to_user((char __user *)data, &connect_data,
 538                                 sizeof(struct mei_connect_client_data))) {
 539                         dev_dbg(dev->dev, "failed to copy data to userland\n");
 540                         rets = -EFAULT;
 541                         goto out;
 542                 }
 543
 544                 break;
 545
 546         case IOCTL_MEI_NOTIFY_SET:
 547                 dev_dbg(dev->dev, ": IOCTL_MEI_NOTIFY_SET.\n");
 548                 if (copy_from_user(&notify_req,
 549                                    (char __user *)data, sizeof(notify_req))) {
 550                         dev_dbg(dev->dev, "failed to copy data from userland\n");
 551                         rets = -EFAULT;
 552                         goto out;
 553                 }
 554                 rets = mei_ioctl_client_notify_request(file, notify_req);
 555                 break;
 556
 557         case IOCTL_MEI_NOTIFY_GET:
 558                 dev_dbg(dev->dev, ": IOCTL_MEI_NOTIFY_GET.\n");
 559                 rets = mei_ioctl_client_notify_get(file, &notify_get);
 560                 if (rets)
 561                         goto out;
 562
 563                 dev_dbg(dev->dev, "copy connect data to user\n");
 564                 if (copy_to_user((char __user *)data,
 565                                 &notify_get, sizeof(notify_get))) {
 566                         dev_dbg(dev->dev, "failed to copy data to userland\n");
 567                         rets = -EFAULT;
 568                         goto out;
 569
 570                 }
 571                 break;
 572
 573         default:
 574                 rets = -ENOIOCTLCMD;
 575         }
 576
 577 out:
 578         mutex_unlock(&dev->device_lock);
 579         return rets;
 580 }
 581
 582 /**
 583  * mei_compat_ioctl - the compat IOCTL function
 584  *
 585  * @file: pointer to file structure
 586  * @cmd: ioctl command
 587  * @data: pointer to mei message structure
 588  *
 589  * Return: 0 on success , <0 on error
 590  */
 591 #ifdef CONFIG_COMPAT
 592 static long mei_compat_ioctl(struct file *file,
 593                         unsigned int cmd, unsigned long data)
 594 {
 595         return mei_ioctl(file, cmd, (unsigned long)compat_ptr(data));
 596 }
 597 #endif
 598
 599
 600 /**
 601  * mei_poll - the poll function
 602  *
 603  * @file: pointer to file structure
 604  * @wait: pointer to poll_table structure
 605  *
 606  * Return: poll mask
 607  */
 608 static unsigned int mei_poll(struct file *file, poll_table *wait)
 609 {
 610         unsigned long req_events = poll_requested_events(wait);
 611         struct mei_cl *cl = file->private_data;
 612         struct mei_device *dev;
 613         unsigned int mask = 0;
 614         bool notify_en;
 615
 616         if (WARN_ON(!cl || !cl->dev))
 617                 return POLLERR;
 618
 619         dev = cl->dev;
 620
 621         mutex_lock(&dev->device_lock);
 622
 623         notify_en = cl->notify_en && (req_events & POLLPRI);
 624
 625         if (dev->dev_state != MEI_DEV_ENABLED ||
 626             !mei_cl_is_connected(cl)) {
 627                 mask = POLLERR;
 628                 goto out;
 629         }
 630
 631         if (cl == &dev->iamthif_cl) {
 632                 mask = mei_amthif_poll(dev, file, wait);
 633                 goto out;
 634         }
 635
 636         if (notify_en) {
 637                 poll_wait(file, &cl->ev_wait, wait);
 638                 if (cl->notify_ev)
 639                         mask |= POLLPRI;
 640         }
 641
 642         if (req_events & (POLLIN | POLLRDNORM)) {
 643                 poll_wait(file, &cl->rx_wait, wait);
 644
 645                 if (!list_empty(&cl->rd_completed))
 646                         mask |= POLLIN | POLLRDNORM;
 647                 else
 648                         mei_cl_read_start(cl, 0, file);
 649         }
 650
 651 out:
 652         mutex_unlock(&dev->device_lock);
 653         return mask;
 654 }
 655
 656 /**
 657  * mei_fasync - asynchronous io support
 658  *
 659  * @fd: file descriptor
 660  * @file: pointer to file structure
 661  * @band: band bitmap
 662  *
 663  * Return: negative on error,
 664  *         0 if it did no changes,
 665  *         and positive a process was added or deleted
 666  */
 667 static int mei_fasync(int fd, struct file *file, int band)
 668 {
 669
 670         struct mei_cl *cl = file->private_data;
 671
 672         if (!mei_cl_is_connected(cl))
 673                 return -ENODEV;
 674
 675         return fasync_helper(fd, file, band, &cl->ev_async);
 676 }
 677
 678 /**
 679  * fw_status_show - mei device attribute show method
 680  *
 681  * @device: device pointer
 682  * @attr: attribute pointer
 683  * @buf:  char out buffer
 684  *
 685  * Return: number of the bytes printed into buf or error
 686  */
 687 static ssize_t fw_status_show(struct device *device,
 688                 struct device_attribute *attr, char *buf)
 689 {
 690         struct mei_device *dev = dev_get_drvdata(device);
 691         struct mei_fw_status fw_status;
 692         int err, i;
 693         ssize_t cnt = 0;
 694
 695         mutex_lock(&dev->device_lock);
 696         err = mei_fw_status(dev, &fw_status);
 697         mutex_unlock(&dev->device_lock);
 698         if (err) {
 699                 dev_err(device, "read fw_status error = %d\n", err);
 700                 return err;
 701         }
 702
 703         for (i = 0; i < fw_status.count; i++)
 704                 cnt += scnprintf(buf + cnt, PAGE_SIZE - cnt, "%08X\n",
 705                                 fw_status.status[i]);
 706         return cnt;
 707 }
 708 static DEVICE_ATTR_RO(fw_status);
 709
 710 static struct attribute *mei_attrs[] = {
 711         &dev_attr_fw_status.attr,
 712         NULL
 713 };
 714 ATTRIBUTE_GROUPS(mei);
 715
 716 /*
 717  * file operations structure will be used for mei char device.
 718  */
 719 static const struct file_operations mei_fops = {
 720         .owner = THIS_MODULE,
 721         .read = mei_read,
 722         .unlocked_ioctl = mei_ioctl,
 723 #ifdef CONFIG_COMPAT
 724         .compat_ioctl = mei_compat_ioctl,
 725 #endif
 726         .open = mei_open,
 727         .release = mei_release,
 728         .write = mei_write,
 729         .poll = mei_poll,
 730         .fasync = mei_fasync,
 731         .llseek = no_llseek
 732 };
 733
 734 static struct class *mei_class;
 735 static dev_t mei_devt;
 736 #define MEI_MAX_DEVS  MINORMASK
 737 static DEFINE_MUTEX(mei_minor_lock);
 738 static DEFINE_IDR(mei_idr);
 739
 740 /**
 741  * mei_minor_get - obtain next free device minor number
 742  *
 743  * @dev:  device pointer
 744  *
 745  * Return: allocated minor, or -ENOSPC if no free minor left
 746  */
 747 static int mei_minor_get(struct mei_device *dev)
 748 {
 749         int ret;
 750
 751         mutex_lock(&mei_minor_lock);
 752         ret = idr_alloc(&mei_idr, dev, 0, MEI_MAX_DEVS, GFP_KERNEL);
 753         if (ret >= 0)
 754                 dev->minor = ret;
 755         else if (ret == -ENOSPC)
 756                 dev_err(dev->dev, "too many mei devices\n");
 757
 758         mutex_unlock(&mei_minor_lock);
 759         return ret;
 760 }
 761
 762 /**
 763  * mei_minor_free - mark device minor number as free
 764  *
 765  * @dev:  device pointer
 766  */
 767 static void mei_minor_free(struct mei_device *dev)
 768 {
 769         mutex_lock(&mei_minor_lock);
 770         idr_remove(&mei_idr, dev->minor);
 771         mutex_unlock(&mei_minor_lock);
 772 }
 773
 774 int mei_register(struct mei_device *dev, struct device *parent)
 775 {
 776         struct device *clsdev; /* class device */
 777         int ret, devno;
 778
 779         ret = mei_minor_get(dev);
 780         if (ret < 0)
 781                 return ret;
 782
 783         /* Fill in the data structures */
 784         devno = MKDEV(MAJOR(mei_devt), dev->minor);
 785         cdev_init(&dev->cdev, &mei_fops);
 786         dev->cdev.owner = parent->driver->owner;
 787
 788         /* Add the device */
 789         ret = cdev_add(&dev->cdev, devno, 1);
 790         if (ret) {
 791                 dev_err(parent, "unable to add device %d:%d\n",
 792                         MAJOR(mei_devt), dev->minor);
 793                 goto err_dev_add;
 794         }
 795
 796         clsdev = device_create_with_groups(mei_class, parent, devno,
 797                                            dev, mei_groups,
 798                                            "mei%d", dev->minor);
 799
 800         if (IS_ERR(clsdev)) {
 801                 dev_err(parent, "unable to create device %d:%d\n",
 802                         MAJOR(mei_devt), dev->minor);
 803                 ret = PTR_ERR(clsdev);
 804                 goto err_dev_create;
 805         }
 806
 807         ret = mei_dbgfs_register(dev, dev_name(clsdev));
 808         if (ret) {
 809                 dev_err(clsdev, "cannot register debugfs ret = %d\n", ret);
 810                 goto err_dev_dbgfs;
 811         }
 812
 813         return 0;
 814
 815 err_dev_dbgfs:
 816         device_destroy(mei_class, devno);
 817 err_dev_create:
 818         cdev_del(&dev->cdev);
 819 err_dev_add:
 820         mei_minor_free(dev);
 821         return ret;
 822 }
 823 EXPORT_SYMBOL_GPL(mei_register);
 824
 825 void mei_deregister(struct mei_device *dev)
 826 {
 827         int devno;
 828
 829         devno = dev->cdev.dev;
 830         cdev_del(&dev->cdev);
 831
 832         mei_dbgfs_deregister(dev);
 833
 834         device_destroy(mei_class, devno);
 835
 836         mei_minor_free(dev);
 837 }
 838 EXPORT_SYMBOL_GPL(mei_deregister);
 839
 840 static int __init mei_init(void)
 841 {
 842         int ret;
 843
 844         mei_class = class_create(THIS_MODULE, "mei");
 845         if (IS_ERR(mei_class)) {
 846                 pr_err("couldn't create class\n");
 847                 ret = PTR_ERR(mei_class);
 848                 goto err;
 849         }
 850
 851         ret = alloc_chrdev_region(&mei_devt, 0, MEI_MAX_DEVS, "mei");
 852         if (ret < 0) {
 853                 pr_err("unable to allocate char dev region\n");
 854                 goto err_class;
 855         }
 856
 857         ret = mei_cl_bus_init();
 858         if (ret < 0) {
 859                 pr_err("unable to initialize bus\n");
 860                 goto err_chrdev;
 861         }
 862
 863         return 0;
 864
 865 err_chrdev:
 866         unregister_chrdev_region(mei_devt, MEI_MAX_DEVS);
 867 err_class:
 868         class_destroy(mei_class);
 869 err:
 870         return ret;
 871 }
 872
 873 static void __exit mei_exit(void)
 874 {
 875         unregister_chrdev_region(mei_devt, MEI_MAX_DEVS);
 876         class_destroy(mei_class);
 877         mei_cl_bus_exit();
 878 }
 879
 880 module_init(mei_init);
 881 module_exit(mei_exit);
 882
 883 MODULE_AUTHOR("Intel Corporation");
 884 MODULE_DESCRIPTION("Intel(R) Management Engine Interface");
 885 MODULE_LICENSE("GPL v2");
 886