net/nfc/core.c

   1 /*
   2  * Copyright (C) 2011 Instituto Nokia de Tecnologia
   3  *
   4  * Authors:
   5  *    Lauro Ramos Venancio <lauro.venancio@openbossa.org>
   6  *    Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
   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 "nfc.h"
  33
  34 #define VERSION "0.1"
  35
  36 int nfc_devlist_generation;
  37 DEFINE_MUTEX(nfc_devlist_mutex);
  38
  39 /**
  40  * nfc_dev_up - turn on the NFC device
  41  *
  42  * @dev: The nfc device to be turned on
  43  *
  44  * The device remains up until the nfc_dev_down function is called.
  45  */
  46 int nfc_dev_up(struct nfc_dev *dev)
  47 {
  48         int rc = 0;
  49
  50         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
  51
  52         device_lock(&dev->dev);
  53
  54         if (!device_is_registered(&dev->dev)) {
  55                 rc = -ENODEV;
  56                 goto error;
  57         }
  58
  59         if (dev->dev_up) {
  60                 rc = -EALREADY;
  61                 goto error;
  62         }
  63
  64         if (dev->ops->dev_up)
  65                 rc = dev->ops->dev_up(dev);
  66
  67         if (!rc)
  68                 dev->dev_up = true;
  69
  70 error:
  71         device_unlock(&dev->dev);
  72         return rc;
  73 }
  74
  75 /**
  76  * nfc_dev_down - turn off the NFC device
  77  *
  78  * @dev: The nfc device to be turned off
  79  */
  80 int nfc_dev_down(struct nfc_dev *dev)
  81 {
  82         int rc = 0;
  83
  84         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
  85
  86         device_lock(&dev->dev);
  87
  88         if (!device_is_registered(&dev->dev)) {
  89                 rc = -ENODEV;
  90                 goto error;
  91         }
  92
  93         if (!dev->dev_up) {
  94                 rc = -EALREADY;
  95                 goto error;
  96         }
  97
  98         if (dev->polling || dev->remote_activated) {
  99                 rc = -EBUSY;
 100                 goto error;
 101         }
 102
 103         if (dev->ops->dev_down)
 104                 dev->ops->dev_down(dev);
 105
 106         dev->dev_up = false;
 107
 108 error:
 109         device_unlock(&dev->dev);
 110         return rc;
 111 }
 112
 113 /**
 114  * nfc_start_poll - start polling for nfc targets
 115  *
 116  * @dev: The nfc device that must start polling
 117  * @protocols: bitset of nfc protocols that must be used for polling
 118  *
 119  * The device remains polling for targets until a target is found or
 120  * the nfc_stop_poll function is called.
 121  */
 122 int nfc_start_poll(struct nfc_dev *dev, u32 protocols)
 123 {
 124         int rc;
 125
 126         pr_debug("dev_name=%s protocols=0x%x\n",
 127                  dev_name(&dev->dev), protocols);
 128
 129         if (!protocols)
 130                 return -EINVAL;
 131
 132         device_lock(&dev->dev);
 133
 134         if (!device_is_registered(&dev->dev)) {
 135                 rc = -ENODEV;
 136                 goto error;
 137         }
 138
 139         if (dev->polling) {
 140                 rc = -EBUSY;
 141                 goto error;
 142         }
 143
 144         rc = dev->ops->start_poll(dev, protocols);
 145         if (!rc)
 146                 dev->polling = true;
 147
 148 error:
 149         device_unlock(&dev->dev);
 150         return rc;
 151 }
 152
 153 /**
 154  * nfc_stop_poll - stop polling for nfc targets
 155  *
 156  * @dev: The nfc device that must stop polling
 157  */
 158 int nfc_stop_poll(struct nfc_dev *dev)
 159 {
 160         int rc = 0;
 161
 162         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 163
 164         device_lock(&dev->dev);
 165
 166         if (!device_is_registered(&dev->dev)) {
 167                 rc = -ENODEV;
 168                 goto error;
 169         }
 170
 171         if (!dev->polling) {
 172                 rc = -EINVAL;
 173                 goto error;
 174         }
 175
 176         dev->ops->stop_poll(dev);
 177         dev->polling = false;
 178
 179 error:
 180         device_unlock(&dev->dev);
 181         return rc;
 182 }
 183
 184 int nfc_dep_link_up(struct nfc_dev *dev, int target_index, u8 comm_mode)
 185 {
 186         int rc = 0;
 187         u8 *gb;
 188         size_t gb_len;
 189
 190         pr_debug("dev_name=%s comm %d\n", dev_name(&dev->dev), comm_mode);
 191
 192         if (!dev->ops->dep_link_up)
 193                 return -EOPNOTSUPP;
 194
 195         device_lock(&dev->dev);
 196
 197         if (!device_is_registered(&dev->dev)) {
 198                 rc = -ENODEV;
 199                 goto error;
 200         }
 201
 202         if (dev->dep_link_up == true) {
 203                 rc = -EALREADY;
 204                 goto error;
 205         }
 206
 207         gb = nfc_llcp_general_bytes(dev, &gb_len);
 208         if (gb_len > NFC_MAX_GT_LEN) {
 209                 rc = -EINVAL;
 210                 goto error;
 211         }
 212
 213         rc = dev->ops->dep_link_up(dev, target_index, comm_mode, gb, gb_len);
 214
 215 error:
 216         device_unlock(&dev->dev);
 217         return rc;
 218 }
 219
 220 int nfc_dep_link_down(struct nfc_dev *dev)
 221 {
 222         int rc = 0;
 223
 224         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 225
 226         if (!dev->ops->dep_link_down)
 227                 return -EOPNOTSUPP;
 228
 229         device_lock(&dev->dev);
 230
 231         if (!device_is_registered(&dev->dev)) {
 232                 rc = -ENODEV;
 233                 goto error;
 234         }
 235
 236         if (dev->dep_link_up == false) {
 237                 rc = -EALREADY;
 238                 goto error;
 239         }
 240
 241         if (dev->dep_rf_mode == NFC_RF_TARGET) {
 242                 rc = -EOPNOTSUPP;
 243                 goto error;
 244         }
 245
 246         rc = dev->ops->dep_link_down(dev);
 247         if (!rc) {
 248                 dev->dep_link_up = false;
 249                 nfc_llcp_mac_is_down(dev);
 250                 nfc_genl_dep_link_down_event(dev);
 251         }
 252
 253 error:
 254         device_unlock(&dev->dev);
 255         return rc;
 256 }
 257
 258 int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
 259                        u8 comm_mode, u8 rf_mode)
 260 {
 261         dev->dep_link_up = true;
 262         dev->dep_rf_mode = rf_mode;
 263
 264         nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);
 265
 266         return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
 267 }
 268 EXPORT_SYMBOL(nfc_dep_link_is_up);
 269
 270 /**
 271  * nfc_activate_target - prepare the target for data exchange
 272  *
 273  * @dev: The nfc device that found the target
 274  * @target_idx: index of the target that must be activated
 275  * @protocol: nfc protocol that will be used for data exchange
 276  */
 277 int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
 278 {
 279         int rc;
 280
 281         pr_debug("dev_name=%s target_idx=%u protocol=%u\n",
 282                  dev_name(&dev->dev), target_idx, protocol);
 283
 284         device_lock(&dev->dev);
 285
 286         if (!device_is_registered(&dev->dev)) {
 287                 rc = -ENODEV;
 288                 goto error;
 289         }
 290
 291         rc = dev->ops->activate_target(dev, target_idx, protocol);
 292         if (!rc)
 293                 dev->remote_activated = true;
 294
 295 error:
 296         device_unlock(&dev->dev);
 297         return rc;
 298 }
 299
 300 /**
 301  * nfc_deactivate_target - deactivate a nfc target
 302  *
 303  * @dev: The nfc device that found the target
 304  * @target_idx: index of the target that must be deactivated
 305  */
 306 int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
 307 {
 308         int rc = 0;
 309
 310         pr_debug("dev_name=%s target_idx=%u\n",
 311                  dev_name(&dev->dev), target_idx);
 312
 313         device_lock(&dev->dev);
 314
 315         if (!device_is_registered(&dev->dev)) {
 316                 rc = -ENODEV;
 317                 goto error;
 318         }
 319
 320         dev->ops->deactivate_target(dev, target_idx);
 321         dev->remote_activated = false;
 322
 323 error:
 324         device_unlock(&dev->dev);
 325         return rc;
 326 }
 327
 328 /**
 329  * nfc_data_exchange - transceive data
 330  *
 331  * @dev: The nfc device that found the target
 332  * @target_idx: index of the target
 333  * @skb: data to be sent
 334  * @cb: callback called when the response is received
 335  * @cb_context: parameter for the callback function
 336  *
 337  * The user must wait for the callback before calling this function again.
 338  */
 339 int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx, struct sk_buff *skb,
 340                       data_exchange_cb_t cb, void *cb_context)
 341 {
 342         int rc;
 343
 344         pr_debug("dev_name=%s target_idx=%u skb->len=%u\n",
 345                  dev_name(&dev->dev), target_idx, skb->len);
 346
 347         device_lock(&dev->dev);
 348
 349         if (!device_is_registered(&dev->dev)) {
 350                 rc = -ENODEV;
 351                 kfree_skb(skb);
 352                 goto error;
 353         }
 354
 355         rc = dev->ops->data_exchange(dev, target_idx, skb, cb, cb_context);
 356
 357 error:
 358         device_unlock(&dev->dev);
 359         return rc;
 360 }
 361
 362 int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
 363 {
 364         pr_debug("dev_name=%s gb_len=%d\n", dev_name(&dev->dev), gb_len);
 365
 366         if (gb_len > NFC_MAX_GT_LEN)
 367                 return -EINVAL;
 368
 369         return nfc_llcp_set_remote_gb(dev, gb, gb_len);
 370 }
 371 EXPORT_SYMBOL(nfc_set_remote_general_bytes);
 372
 373 /**
 374  * nfc_alloc_send_skb - allocate a skb for data exchange responses
 375  *
 376  * @size: size to allocate
 377  * @gfp: gfp flags
 378  */
 379 struct sk_buff *nfc_alloc_send_skb(struct nfc_dev *dev, struct sock *sk,
 380                                    unsigned int flags, unsigned int size,
 381                                    unsigned int *err)
 382 {
 383         struct sk_buff *skb;
 384         unsigned int total_size;
 385
 386         total_size = size +
 387                 dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
 388
 389         skb = sock_alloc_send_skb(sk, total_size, flags & MSG_DONTWAIT, err);
 390         if (skb)
 391                 skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
 392
 393         return skb;
 394 }
 395
 396 /**
 397  * nfc_alloc_recv_skb - allocate a skb for data exchange responses
 398  *
 399  * @size: size to allocate
 400  * @gfp: gfp flags
 401  */
 402 struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp)
 403 {
 404         struct sk_buff *skb;
 405         unsigned int total_size;
 406
 407         total_size = size + 1;
 408         skb = alloc_skb(total_size, gfp);
 409
 410         if (skb)
 411                 skb_reserve(skb, 1);
 412
 413         return skb;
 414 }
 415 EXPORT_SYMBOL(nfc_alloc_recv_skb);
 416
 417 /**
 418  * nfc_targets_found - inform that targets were found
 419  *
 420  * @dev: The nfc device that found the targets
 421  * @targets: array of nfc targets found
 422  * @ntargets: targets array size
 423  *
 424  * The device driver must call this function when one or many nfc targets
 425  * are found. After calling this function, the device driver must stop
 426  * polling for targets.
 427  */
 428 int nfc_targets_found(struct nfc_dev *dev,
 429                       struct nfc_target *targets, int n_targets)
 430 {
 431         pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);
 432
 433         dev->polling = false;
 434
 435         spin_lock_bh(&dev->targets_lock);
 436
 437         dev->targets_generation++;
 438
 439         kfree(dev->targets);
 440         dev->targets = kmemdup(targets, n_targets * sizeof(struct nfc_target),
 441                                GFP_ATOMIC);
 442
 443         if (!dev->targets) {
 444                 dev->n_targets = 0;
 445                 spin_unlock_bh(&dev->targets_lock);
 446                 return -ENOMEM;
 447         }
 448
 449         dev->n_targets = n_targets;
 450         spin_unlock_bh(&dev->targets_lock);
 451
 452         nfc_genl_targets_found(dev);
 453
 454         return 0;
 455 }
 456 EXPORT_SYMBOL(nfc_targets_found);
 457
 458 static void nfc_release(struct device *d)
 459 {
 460         struct nfc_dev *dev = to_nfc_dev(d);
 461
 462         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 463
 464         nfc_genl_data_exit(&dev->genl_data);
 465         kfree(dev->targets);
 466         kfree(dev);
 467 }
 468
 469 struct class nfc_class = {
 470         .name = "nfc",
 471         .dev_release = nfc_release,
 472 };
 473 EXPORT_SYMBOL(nfc_class);
 474
 475 static int match_idx(struct device *d, void *data)
 476 {
 477         struct nfc_dev *dev = to_nfc_dev(d);
 478         unsigned *idx = data;
 479
 480         return dev->idx == *idx;
 481 }
 482
 483 struct nfc_dev *nfc_get_device(unsigned idx)
 484 {
 485         struct device *d;
 486
 487         d = class_find_device(&nfc_class, NULL, &idx, match_idx);
 488         if (!d)
 489                 return NULL;
 490
 491         return to_nfc_dev(d);
 492 }
 493
 494 /**
 495  * nfc_allocate_device - allocate a new nfc device
 496  *
 497  * @ops: device operations
 498  * @supported_protocols: NFC protocols supported by the device
 499  */
 500 struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 501                                     u32 supported_protocols,
 502                                     int tx_headroom, int tx_tailroom)
 503 {
 504         static atomic_t dev_no = ATOMIC_INIT(0);
 505         struct nfc_dev *dev;
 506
 507         if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
 508             !ops->deactivate_target || !ops->data_exchange)
 509                 return NULL;
 510
 511         if (!supported_protocols)
 512                 return NULL;
 513
 514         dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
 515         if (!dev)
 516                 return NULL;
 517
 518         dev->dev.class = &nfc_class;
 519         dev->idx = atomic_inc_return(&dev_no) - 1;
 520         dev_set_name(&dev->dev, "nfc%d", dev->idx);
 521         device_initialize(&dev->dev);
 522
 523         dev->ops = ops;
 524         dev->supported_protocols = supported_protocols;
 525         dev->tx_headroom = tx_headroom;
 526         dev->tx_tailroom = tx_tailroom;
 527
 528         spin_lock_init(&dev->targets_lock);
 529         nfc_genl_data_init(&dev->genl_data);
 530
 531         /* first generation must not be 0 */
 532         dev->targets_generation = 1;
 533
 534         return dev;
 535 }
 536 EXPORT_SYMBOL(nfc_allocate_device);
 537
 538 /**
 539  * nfc_register_device - register a nfc device in the nfc subsystem
 540  *
 541  * @dev: The nfc device to register
 542  */
 543 int nfc_register_device(struct nfc_dev *dev)
 544 {
 545         int rc;
 546
 547         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 548
 549         mutex_lock(&nfc_devlist_mutex);
 550         nfc_devlist_generation++;
 551         rc = device_add(&dev->dev);
 552         mutex_unlock(&nfc_devlist_mutex);
 553
 554         if (rc < 0)
 555                 return rc;
 556
 557         rc = nfc_llcp_register_device(dev);
 558         if (rc)
 559                 pr_err("Could not register llcp device\n");
 560
 561         rc = nfc_genl_device_added(dev);
 562         if (rc)
 563                 pr_debug("The userspace won't be notified that the device %s was added\n",
 564                          dev_name(&dev->dev));
 565
 566         return 0;
 567 }
 568 EXPORT_SYMBOL(nfc_register_device);
 569
 570 /**
 571  * nfc_unregister_device - unregister a nfc device in the nfc subsystem
 572  *
 573  * @dev: The nfc device to unregister
 574  */
 575 void nfc_unregister_device(struct nfc_dev *dev)
 576 {
 577         int rc;
 578
 579         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 580
 581         mutex_lock(&nfc_devlist_mutex);
 582         nfc_devlist_generation++;
 583
 584         /* lock to avoid unregistering a device while an operation
 585            is in progress */
 586         device_lock(&dev->dev);
 587         device_del(&dev->dev);
 588         device_unlock(&dev->dev);
 589
 590         mutex_unlock(&nfc_devlist_mutex);
 591
 592         nfc_llcp_unregister_device(dev);
 593
 594         rc = nfc_genl_device_removed(dev);
 595         if (rc)
 596                 pr_debug("The userspace won't be notified that the device %s was removed\n",
 597                          dev_name(&dev->dev));
 598
 599 }
 600 EXPORT_SYMBOL(nfc_unregister_device);
 601
 602 static int __init nfc_init(void)
 603 {
 604         int rc;
 605
 606         pr_info("NFC Core ver %s\n", VERSION);
 607
 608         rc = class_register(&nfc_class);
 609         if (rc)
 610                 return rc;
 611
 612         rc = nfc_genl_init();
 613         if (rc)
 614                 goto err_genl;
 615
 616         /* the first generation must not be 0 */
 617         nfc_devlist_generation = 1;
 618
 619         rc = rawsock_init();
 620         if (rc)
 621                 goto err_rawsock;
 622
 623         rc = nfc_llcp_init();
 624         if (rc)
 625                 goto err_llcp_sock;
 626
 627         rc = af_nfc_init();
 628         if (rc)
 629                 goto err_af_nfc;
 630
 631         return 0;
 632
 633 err_af_nfc:
 634         nfc_llcp_exit();
 635 err_llcp_sock:
 636         rawsock_exit();
 637 err_rawsock:
 638         nfc_genl_exit();
 639 err_genl:
 640         class_unregister(&nfc_class);
 641         return rc;
 642 }
 643
 644 static void __exit nfc_exit(void)
 645 {
 646         af_nfc_exit();
 647         nfc_llcp_exit();
 648         rawsock_exit();
 649         nfc_genl_exit();
 650         class_unregister(&nfc_class);
 651 }
 652
 653 subsys_initcall(nfc_init);
 654 module_exit(nfc_exit);
 655
 656 MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@openbossa.org>");
 657 MODULE_DESCRIPTION("NFC Core ver " VERSION);
 658 MODULE_VERSION(VERSION);
 659 MODULE_LICENSE("GPL");