net/nfc/core.c

   1 /*
   2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
   3  *
   4  * Authors:
   5  *    Lauro Ramos Venancio <[email protected]>
   6  *    Aloisio Almeida Jr <[email protected]>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the
  20  * Free Software Foundation, Inc.,
  21  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  22  */
  23
  24 #define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
  25
  26 #include <linux/init.h>
  27 #include <linux/kernel.h>
  28 #include <linux/module.h>
  29 #include <linux/slab.h>
  30 #include <linux/nfc.h>
  31
  32 #include <net/genetlink.h>
  33
  34 #include "nfc.h"
  35
  36 #define VERSION "0.1"
  37
  38 #define NFC_CHECK_PRES_FREQ_MS  2000
  39
  40 int nfc_devlist_generation;
  41 DEFINE_MUTEX(nfc_devlist_mutex);
  42
  43 /**
  44  * nfc_dev_up - turn on the NFC device
  45  *
  46  * @dev: The nfc device to be turned on
  47  *
  48  * The device remains up until the nfc_dev_down function is called.
  49  */
  50 int nfc_dev_up(struct nfc_dev *dev)
  51 {
  52         int rc = 0;
  53
  54         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
  55
  56         device_lock(&dev->dev);
  57
  58         if (!device_is_registered(&dev->dev)) {
  59                 rc = -ENODEV;
  60                 goto error;
  61         }
  62
  63         if (dev->dev_up) {
  64                 rc = -EALREADY;
  65                 goto error;
  66         }
  67
  68         if (dev->ops->dev_up)
  69                 rc = dev->ops->dev_up(dev);
  70
  71         if (!rc)
  72                 dev->dev_up = true;
  73
  74 error:
  75         device_unlock(&dev->dev);
  76         return rc;
  77 }
  78
  79 /**
  80  * nfc_dev_down - turn off the NFC device
  81  *
  82  * @dev: The nfc device to be turned off
  83  */
  84 int nfc_dev_down(struct nfc_dev *dev)
  85 {
  86         int rc = 0;
  87
  88         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
  89
  90         device_lock(&dev->dev);
  91
  92         if (!device_is_registered(&dev->dev)) {
  93                 rc = -ENODEV;
  94                 goto error;
  95         }
  96
  97         if (!dev->dev_up) {
  98                 rc = -EALREADY;
  99                 goto error;
 100         }
 101
 102         if (dev->polling || dev->active_target) {
 103                 rc = -EBUSY;
 104                 goto error;
 105         }
 106
 107         if (dev->ops->dev_down)
 108                 dev->ops->dev_down(dev);
 109
 110         dev->dev_up = false;
 111
 112 error:
 113         device_unlock(&dev->dev);
 114         return rc;
 115 }
 116
 117 /**
 118  * nfc_start_poll - start polling for nfc targets
 119  *
 120  * @dev: The nfc device that must start polling
 121  * @protocols: bitset of nfc protocols that must be used for polling
 122  *
 123  * The device remains polling for targets until a target is found or
 124  * the nfc_stop_poll function is called.
 125  */
 126 int nfc_start_poll(struct nfc_dev *dev, u32 im_protocols, u32 tm_protocols)
 127 {
 128         int rc;
 129
 130         pr_debug("dev_name %s initiator protocols 0x%x target protocols 0x%x\n",
 131                  dev_name(&dev->dev), im_protocols, tm_protocols);
 132
 133         if (!im_protocols && !tm_protocols)
 134                 return -EINVAL;
 135
 136         device_lock(&dev->dev);
 137
 138         if (!device_is_registered(&dev->dev)) {
 139                 rc = -ENODEV;
 140                 goto error;
 141         }
 142
 143         if (dev->polling) {
 144                 rc = -EBUSY;
 145                 goto error;
 146         }
 147
 148         rc = dev->ops->start_poll(dev, im_protocols, tm_protocols);
 149         if (!rc) {
 150                 dev->polling = true;
 151                 dev->rf_mode = NFC_RF_NONE;
 152         }
 153
 154 error:
 155         device_unlock(&dev->dev);
 156         return rc;
 157 }
 158
 159 /**
 160  * nfc_stop_poll - stop polling for nfc targets
 161  *
 162  * @dev: The nfc device that must stop polling
 163  */
 164 int nfc_stop_poll(struct nfc_dev *dev)
 165 {
 166         int rc = 0;
 167
 168         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 169
 170         device_lock(&dev->dev);
 171
 172         if (!device_is_registered(&dev->dev)) {
 173                 rc = -ENODEV;
 174                 goto error;
 175         }
 176
 177         if (!dev->polling) {
 178                 rc = -EINVAL;
 179                 goto error;
 180         }
 181
 182         dev->ops->stop_poll(dev);
 183         dev->polling = false;
 184
 185 error:
 186         device_unlock(&dev->dev);
 187         return rc;
 188 }
 189
 190 static struct nfc_target *nfc_find_target(struct nfc_dev *dev, u32 target_idx)
 191 {
 192         int i;
 193
 194         if (dev->n_targets == 0)
 195                 return NULL;
 196
 197         for (i = 0; i < dev->n_targets ; i++) {
 198                 if (dev->targets[i].idx == target_idx)
 199                         return &dev->targets[i];
 200         }
 201
 202         return NULL;
 203 }
 204
 205 int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode)
 206 {
 207         int rc = 0;
 208         u8 *gb;
 209         size_t gb_len;
 210         struct nfc_target *target;
 211
 212         pr_debug("dev_name=%s comm %d\n", dev_name(&dev->dev), comm_mode);
 213
 214         if (!dev->ops->dep_link_up)
 215                 return -EOPNOTSUPP;
 216
 217         device_lock(&dev->dev);
 218
 219         if (!device_is_registered(&dev->dev)) {
 220                 rc = -ENODEV;
 221                 goto error;
 222         }
 223
 224         if (dev->dep_link_up == true) {
 225                 rc = -EALREADY;
 226                 goto error;
 227         }
 228
 229         gb = nfc_llcp_general_bytes(dev, &gb_len);
 230         if (gb_len > NFC_MAX_GT_LEN) {
 231                 rc = -EINVAL;
 232                 goto error;
 233         }
 234
 235         target = nfc_find_target(dev, target_index);
 236         if (target == NULL) {
 237                 rc = -ENOTCONN;
 238                 goto error;
 239         }
 240
 241         rc = dev->ops->dep_link_up(dev, target, comm_mode, gb, gb_len);
 242         if (!rc) {
 243                 dev->active_target = target;
 244                 dev->rf_mode = NFC_RF_INITIATOR;
 245         }
 246
 247 error:
 248         device_unlock(&dev->dev);
 249         return rc;
 250 }
 251
 252 int nfc_dep_link_down(struct nfc_dev *dev)
 253 {
 254         int rc = 0;
 255
 256         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 257
 258         if (!dev->ops->dep_link_down)
 259                 return -EOPNOTSUPP;
 260
 261         device_lock(&dev->dev);
 262
 263         if (!device_is_registered(&dev->dev)) {
 264                 rc = -ENODEV;
 265                 goto error;
 266         }
 267
 268         if (dev->dep_link_up == false) {
 269                 rc = -EALREADY;
 270                 goto error;
 271         }
 272
 273         rc = dev->ops->dep_link_down(dev);
 274         if (!rc) {
 275                 dev->dep_link_up = false;
 276                 dev->active_target = NULL;
 277                 nfc_llcp_mac_is_down(dev);
 278                 nfc_genl_dep_link_down_event(dev);
 279         }
 280
 281 error:
 282         device_unlock(&dev->dev);
 283         return rc;
 284 }
 285
 286 int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
 287                        u8 comm_mode, u8 rf_mode)
 288 {
 289         dev->dep_link_up = true;
 290
 291         nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);
 292
 293         return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
 294 }
 295 EXPORT_SYMBOL(nfc_dep_link_is_up);
 296
 297 /**
 298  * nfc_activate_target - prepare the target for data exchange
 299  *
 300  * @dev: The nfc device that found the target
 301  * @target_idx: index of the target that must be activated
 302  * @protocol: nfc protocol that will be used for data exchange
 303  */
 304 int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
 305 {
 306         int rc;
 307         struct nfc_target *target;
 308
 309         pr_debug("dev_name=%s target_idx=%u protocol=%u\n",
 310                  dev_name(&dev->dev), target_idx, protocol);
 311
 312         device_lock(&dev->dev);
 313
 314         if (!device_is_registered(&dev->dev)) {
 315                 rc = -ENODEV;
 316                 goto error;
 317         }
 318
 319         if (dev->active_target) {
 320                 rc = -EBUSY;
 321                 goto error;
 322         }
 323
 324         target = nfc_find_target(dev, target_idx);
 325         if (target == NULL) {
 326                 rc = -ENOTCONN;
 327                 goto error;
 328         }
 329
 330         rc = dev->ops->activate_target(dev, target, protocol);
 331         if (!rc) {
 332                 dev->active_target = target;
 333                 dev->rf_mode = NFC_RF_INITIATOR;
 334
 335                 if (dev->ops->check_presence)
 336                         mod_timer(&dev->check_pres_timer, jiffies +
 337                                   msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
 338         }
 339
 340 error:
 341         device_unlock(&dev->dev);
 342         return rc;
 343 }
 344
 345 /**
 346  * nfc_deactivate_target - deactivate a nfc target
 347  *
 348  * @dev: The nfc device that found the target
 349  * @target_idx: index of the target that must be deactivated
 350  */
 351 int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
 352 {
 353         int rc = 0;
 354
 355         pr_debug("dev_name=%s target_idx=%u\n",
 356                  dev_name(&dev->dev), target_idx);
 357
 358         device_lock(&dev->dev);
 359
 360         if (!device_is_registered(&dev->dev)) {
 361                 rc = -ENODEV;
 362                 goto error;
 363         }
 364
 365         if (dev->active_target == NULL) {
 366                 rc = -ENOTCONN;
 367                 goto error;
 368         }
 369
 370         if (dev->active_target->idx != target_idx) {
 371                 rc = -ENOTCONN;
 372                 goto error;
 373         }
 374
 375         if (dev->ops->check_presence)
 376                 del_timer_sync(&dev->check_pres_timer);
 377
 378         dev->ops->deactivate_target(dev, dev->active_target);
 379         dev->active_target = NULL;
 380
 381 error:
 382         device_unlock(&dev->dev);
 383         return rc;
 384 }
 385
 386 /**
 387  * nfc_data_exchange - transceive data
 388  *
 389  * @dev: The nfc device that found the target
 390  * @target_idx: index of the target
 391  * @skb: data to be sent
 392  * @cb: callback called when the response is received
 393  * @cb_context: parameter for the callback function
 394  *
 395  * The user must wait for the callback before calling this function again.
 396  */
 397 int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
 398                       data_exchange_cb_t cb, void *cb_context)
 399 {
 400         int rc;
 401
 402         pr_debug("dev_name=%s target_idx=%u skb->len=%u\n",
 403                  dev_name(&dev->dev), target_idx, skb->len);
 404
 405         device_lock(&dev->dev);
 406
 407         if (!device_is_registered(&dev->dev)) {
 408                 rc = -ENODEV;
 409                 kfree_skb(skb);
 410                 goto error;
 411         }
 412
 413         if (dev->rf_mode == NFC_RF_INITIATOR && dev->active_target != NULL) {
 414                 if (dev->active_target->idx != target_idx) {
 415                         rc = -EADDRNOTAVAIL;
 416                         kfree_skb(skb);
 417                         goto error;
 418                 }
 419
 420                 if (dev->ops->check_presence)
 421                         del_timer_sync(&dev->check_pres_timer);
 422
 423                 rc = dev->ops->im_transceive(dev, dev->active_target, skb, cb,
 424                                              cb_context);
 425
 426                 if (!rc && dev->ops->check_presence)
 427                         mod_timer(&dev->check_pres_timer, jiffies +
 428                                   msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
 429         } else if (dev->rf_mode == NFC_RF_TARGET && dev->ops->tm_send != NULL) {
 430                 rc = dev->ops->tm_send(dev, skb);
 431         } else {
 432                 rc = -ENOTCONN;
 433                 kfree_skb(skb);
 434                 goto error;
 435         }
 436
 437
 438 error:
 439         device_unlock(&dev->dev);
 440         return rc;
 441 }
 442
 443 int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
 444 {
 445         pr_debug("dev_name=%s gb_len=%d\n", dev_name(&dev->dev), gb_len);
 446
 447         if (gb_len > NFC_MAX_GT_LEN)
 448                 return -EINVAL;
 449
 450         return nfc_llcp_set_remote_gb(dev, gb, gb_len);
 451 }
 452 EXPORT_SYMBOL(nfc_set_remote_general_bytes);
 453
 454 u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, size_t *gb_len)
 455 {
 456         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 457
 458         return nfc_llcp_general_bytes(dev, gb_len);
 459 }
 460 EXPORT_SYMBOL(nfc_get_local_general_bytes);
 461
 462 int nfc_tm_data_received(struct nfc_dev *dev, struct sk_buff *skb)
 463 {
 464         /* Only LLCP target mode for now */
 465         if (dev->dep_link_up == false) {
 466                 kfree_skb(skb);
 467                 return -ENOLINK;
 468         }
 469
 470         return nfc_llcp_data_received(dev, skb);
 471 }
 472 EXPORT_SYMBOL(nfc_tm_data_received);
 473
 474 int nfc_tm_activated(struct nfc_dev *dev, u32 protocol, u8 comm_mode,
 475                      u8 *gb, size_t gb_len)
 476 {
 477         int rc;
 478
 479         device_lock(&dev->dev);
 480
 481         dev->polling = false;
 482
 483         if (gb != NULL) {
 484                 rc = nfc_set_remote_general_bytes(dev, gb, gb_len);
 485                 if (rc < 0)
 486                         goto out;
 487         }
 488
 489         dev->rf_mode = NFC_RF_TARGET;
 490
 491         if (protocol == NFC_PROTO_NFC_DEP_MASK)
 492                 nfc_dep_link_is_up(dev, 0, comm_mode, NFC_RF_TARGET);
 493
 494         rc = nfc_genl_tm_activated(dev, protocol);
 495
 496 out:
 497         device_unlock(&dev->dev);
 498
 499         return rc;
 500 }
 501 EXPORT_SYMBOL(nfc_tm_activated);
 502
 503 int nfc_tm_deactivated(struct nfc_dev *dev)
 504 {
 505         dev->dep_link_up = false;
 506
 507         return nfc_genl_tm_deactivated(dev);
 508 }
 509 EXPORT_SYMBOL(nfc_tm_deactivated);
 510
 511 /**
 512  * nfc_alloc_send_skb - allocate a skb for data exchange responses
 513  *
 514  * @size: size to allocate
 515  * @gfp: gfp flags
 516  */
 517 struct sk_buff *nfc_alloc_send_skb(struct nfc_dev *dev, struct sock *sk,
 518                                    unsigned int flags, unsigned int size,
 519                                    unsigned int *err)
 520 {
 521         struct sk_buff *skb;
 522         unsigned int total_size;
 523
 524         total_size = size +
 525                 dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
 526
 527         skb = sock_alloc_send_skb(sk, total_size, flags & MSG_DONTWAIT, err);
 528         if (skb)
 529                 skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
 530
 531         return skb;
 532 }
 533
 534 /**
 535  * nfc_alloc_recv_skb - allocate a skb for data exchange responses
 536  *
 537  * @size: size to allocate
 538  * @gfp: gfp flags
 539  */
 540 struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp)
 541 {
 542         struct sk_buff *skb;
 543         unsigned int total_size;
 544
 545         total_size = size + 1;
 546         skb = alloc_skb(total_size, gfp);
 547
 548         if (skb)
 549                 skb_reserve(skb, 1);
 550
 551         return skb;
 552 }
 553 EXPORT_SYMBOL(nfc_alloc_recv_skb);
 554
 555 /**
 556  * nfc_targets_found - inform that targets were found
 557  *
 558  * @dev: The nfc device that found the targets
 559  * @targets: array of nfc targets found
 560  * @ntargets: targets array size
 561  *
 562  * The device driver must call this function when one or many nfc targets
 563  * are found. After calling this function, the device driver must stop
 564  * polling for targets.
 565  * NOTE: This function can be called with targets=NULL and n_targets=0 to
 566  * notify a driver error, meaning that the polling operation cannot complete.
 567  * IMPORTANT: this function must not be called from an atomic context.
 568  * In addition, it must also not be called from a context that would prevent
 569  * the NFC Core to call other nfc ops entry point concurrently.
 570  */
 571 int nfc_targets_found(struct nfc_dev *dev,
 572                       struct nfc_target *targets, int n_targets)
 573 {
 574         int i;
 575
 576         pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);
 577
 578         for (i = 0; i < n_targets; i++)
 579                 targets[i].idx = dev->target_next_idx++;
 580
 581         device_lock(&dev->dev);
 582
 583         if (dev->polling == false) {
 584                 device_unlock(&dev->dev);
 585                 return 0;
 586         }
 587
 588         dev->polling = false;
 589
 590         dev->targets_generation++;
 591
 592         kfree(dev->targets);
 593         dev->targets = NULL;
 594
 595         if (targets) {
 596                 dev->targets = kmemdup(targets,
 597                                        n_targets * sizeof(struct nfc_target),
 598                                        GFP_ATOMIC);
 599
 600                 if (!dev->targets) {
 601                         dev->n_targets = 0;
 602                         device_unlock(&dev->dev);
 603                         return -ENOMEM;
 604                 }
 605         }
 606
 607         dev->n_targets = n_targets;
 608         device_unlock(&dev->dev);
 609
 610         nfc_genl_targets_found(dev);
 611
 612         return 0;
 613 }
 614 EXPORT_SYMBOL(nfc_targets_found);
 615
 616 /**
 617  * nfc_target_lost - inform that an activated target went out of field
 618  *
 619  * @dev: The nfc device that had the activated target in field
 620  * @target_idx: the nfc index of the target
 621  *
 622  * The device driver must call this function when the activated target
 623  * goes out of the field.
 624  * IMPORTANT: this function must not be called from an atomic context.
 625  * In addition, it must also not be called from a context that would prevent
 626  * the NFC Core to call other nfc ops entry point concurrently.
 627  */
 628 int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)
 629 {
 630         struct nfc_target *tg;
 631         int i;
 632
 633         pr_debug("dev_name %s n_target %d\n", dev_name(&dev->dev), target_idx);
 634
 635         device_lock(&dev->dev);
 636
 637         for (i = 0; i < dev->n_targets; i++) {
 638                 tg = &dev->targets[i];
 639                 if (tg->idx == target_idx)
 640                         break;
 641         }
 642
 643         if (i == dev->n_targets) {
 644                 device_unlock(&dev->dev);
 645                 return -EINVAL;
 646         }
 647
 648         dev->targets_generation++;
 649         dev->n_targets--;
 650         dev->active_target = NULL;
 651
 652         if (dev->n_targets) {
 653                 memcpy(&dev->targets[i], &dev->targets[i + 1],
 654                        (dev->n_targets - i) * sizeof(struct nfc_target));
 655         } else {
 656                 kfree(dev->targets);
 657                 dev->targets = NULL;
 658         }
 659
 660         device_unlock(&dev->dev);
 661
 662         nfc_genl_target_lost(dev, target_idx);
 663
 664         return 0;
 665 }
 666 EXPORT_SYMBOL(nfc_target_lost);
 667
 668 inline void nfc_driver_failure(struct nfc_dev *dev, int err)
 669 {
 670         nfc_targets_found(dev, NULL, 0);
 671 }
 672 EXPORT_SYMBOL(nfc_driver_failure);
 673
 674 static void nfc_release(struct device *d)
 675 {
 676         struct nfc_dev *dev = to_nfc_dev(d);
 677
 678         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 679
 680         if (dev->ops->check_presence) {
 681                 del_timer_sync(&dev->check_pres_timer);
 682                 cancel_work_sync(&dev->check_pres_work);
 683         }
 684
 685         nfc_genl_data_exit(&dev->genl_data);
 686         kfree(dev->targets);
 687         kfree(dev);
 688 }
 689
 690 static void nfc_check_pres_work(struct work_struct *work)
 691 {
 692         struct nfc_dev *dev = container_of(work, struct nfc_dev,
 693                                            check_pres_work);
 694         int rc;
 695
 696         device_lock(&dev->dev);
 697
 698         if (dev->active_target && timer_pending(&dev->check_pres_timer) == 0) {
 699                 rc = dev->ops->check_presence(dev, dev->active_target);
 700                 if (!rc) {
 701                         mod_timer(&dev->check_pres_timer, jiffies +
 702                                   msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));
 703                 } else {
 704                         u32 active_target_idx = dev->active_target->idx;
 705                         device_unlock(&dev->dev);
 706                         nfc_target_lost(dev, active_target_idx);
 707                         return;
 708                 }
 709         }
 710
 711         device_unlock(&dev->dev);
 712 }
 713
 714 static void nfc_check_pres_timeout(unsigned long data)
 715 {
 716         struct nfc_dev *dev = (struct nfc_dev *)data;
 717
 718         schedule_work(&dev->check_pres_work);
 719 }
 720
 721 struct class nfc_class = {
 722         .name = "nfc",
 723         .dev_release = nfc_release,
 724 };
 725 EXPORT_SYMBOL(nfc_class);
 726
 727 static int match_idx(struct device *d, void *data)
 728 {
 729         struct nfc_dev *dev = to_nfc_dev(d);
 730         unsigned int *idx = data;
 731
 732         return dev->idx == *idx;
 733 }
 734
 735 struct nfc_dev *nfc_get_device(unsigned int idx)
 736 {
 737         struct device *d;
 738
 739         d = class_find_device(&nfc_class, NULL, &idx, match_idx);
 740         if (!d)
 741                 return NULL;
 742
 743         return to_nfc_dev(d);
 744 }
 745
 746 /**
 747  * nfc_allocate_device - allocate a new nfc device
 748  *
 749  * @ops: device operations
 750  * @supported_protocols: NFC protocols supported by the device
 751  */
 752 struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 753                                     u32 supported_protocols,
 754                                     int tx_headroom, int tx_tailroom)
 755 {
 756         static atomic_t dev_no = ATOMIC_INIT(0);
 757         struct nfc_dev *dev;
 758
 759         if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
 760             !ops->deactivate_target || !ops->im_transceive)
 761                 return NULL;
 762
 763         if (!supported_protocols)
 764                 return NULL;
 765
 766         dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
 767         if (!dev)
 768                 return NULL;
 769
 770         dev->dev.class = &nfc_class;
 771         dev->idx = atomic_inc_return(&dev_no) - 1;
 772         dev_set_name(&dev->dev, "nfc%d", dev->idx);
 773         device_initialize(&dev->dev);
 774
 775         dev->ops = ops;
 776         dev->supported_protocols = supported_protocols;
 777         dev->tx_headroom = tx_headroom;
 778         dev->tx_tailroom = tx_tailroom;
 779
 780         nfc_genl_data_init(&dev->genl_data);
 781
 782
 783         /* first generation must not be 0 */
 784         dev->targets_generation = 1;
 785
 786         if (ops->check_presence) {
 787                 init_timer(&dev->check_pres_timer);
 788                 dev->check_pres_timer.data = (unsigned long)dev;
 789                 dev->check_pres_timer.function = nfc_check_pres_timeout;
 790
 791                 INIT_WORK(&dev->check_pres_work, nfc_check_pres_work);
 792         }
 793
 794         return dev;
 795 }
 796 EXPORT_SYMBOL(nfc_allocate_device);
 797
 798 /**
 799  * nfc_register_device - register a nfc device in the nfc subsystem
 800  *
 801  * @dev: The nfc device to register
 802  */
 803 int nfc_register_device(struct nfc_dev *dev)
 804 {
 805         int rc;
 806
 807         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 808
 809         mutex_lock(&nfc_devlist_mutex);
 810         nfc_devlist_generation++;
 811         rc = device_add(&dev->dev);
 812         mutex_unlock(&nfc_devlist_mutex);
 813
 814         if (rc < 0)
 815                 return rc;
 816
 817         rc = nfc_llcp_register_device(dev);
 818         if (rc)
 819                 pr_err("Could not register llcp device\n");
 820
 821         rc = nfc_genl_device_added(dev);
 822         if (rc)
 823                 pr_debug("The userspace won't be notified that the device %s was added\n",
 824                          dev_name(&dev->dev));
 825
 826         return 0;
 827 }
 828 EXPORT_SYMBOL(nfc_register_device);
 829
 830 /**
 831  * nfc_unregister_device - unregister a nfc device in the nfc subsystem
 832  *
 833  * @dev: The nfc device to unregister
 834  */
 835 void nfc_unregister_device(struct nfc_dev *dev)
 836 {
 837         int rc;
 838
 839         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 840
 841         mutex_lock(&nfc_devlist_mutex);
 842         nfc_devlist_generation++;
 843
 844         /* lock to avoid unregistering a device while an operation
 845            is in progress */
 846         device_lock(&dev->dev);
 847         device_del(&dev->dev);
 848         device_unlock(&dev->dev);
 849
 850         mutex_unlock(&nfc_devlist_mutex);
 851
 852         nfc_llcp_unregister_device(dev);
 853
 854         rc = nfc_genl_device_removed(dev);
 855         if (rc)
 856                 pr_debug("The userspace won't be notified that the device %s was removed\n",
 857                          dev_name(&dev->dev));
 858
 859 }
 860 EXPORT_SYMBOL(nfc_unregister_device);
 861
 862 static int __init nfc_init(void)
 863 {
 864         int rc;
 865
 866         pr_info("NFC Core ver %s\n", VERSION);
 867
 868         rc = class_register(&nfc_class);
 869         if (rc)
 870                 return rc;
 871
 872         rc = nfc_genl_init();
 873         if (rc)
 874                 goto err_genl;
 875
 876         /* the first generation must not be 0 */
 877         nfc_devlist_generation = 1;
 878
 879         rc = rawsock_init();
 880         if (rc)
 881                 goto err_rawsock;
 882
 883         rc = nfc_llcp_init();
 884         if (rc)
 885                 goto err_llcp_sock;
 886
 887         rc = af_nfc_init();
 888         if (rc)
 889                 goto err_af_nfc;
 890
 891         return 0;
 892
 893 err_af_nfc:
 894         nfc_llcp_exit();
 895 err_llcp_sock:
 896         rawsock_exit();
 897 err_rawsock:
 898         nfc_genl_exit();
 899 err_genl:
 900         class_unregister(&nfc_class);
 901         return rc;
 902 }
 903
 904 static void __exit nfc_exit(void)
 905 {
 906         af_nfc_exit();
 907         nfc_llcp_exit();
 908         rawsock_exit();
 909         nfc_genl_exit();
 910         class_unregister(&nfc_class);
 911 }
 912
 913 subsys_initcall(nfc_init);
 914 module_exit(nfc_exit);
 915
 916 MODULE_AUTHOR("Lauro Ramos Venancio <[email protected]>");
 917 MODULE_DESCRIPTION("NFC Core ver " VERSION);
 918 MODULE_VERSION(VERSION);
 919 MODULE_LICENSE("GPL");
 920 MODULE_ALIAS_NETPROTO(PF_NFC);
 921 MODULE_ALIAS_GENL_FAMILY(NFC_GENL_NAME);