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,
 185                                         u8 comm_mode, u8 rf_mode)
 186 {
 187         int rc = 0;
 188
 189         pr_debug("dev_name=%s comm:%d rf:%d\n",
 190                         dev_name(&dev->dev), comm_mode, rf_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         rc = dev->ops->dep_link_up(dev, target_index, comm_mode, rf_mode);
 208
 209 error:
 210         device_unlock(&dev->dev);
 211         return rc;
 212 }
 213
 214 int nfc_dep_link_down(struct nfc_dev *dev)
 215 {
 216         int rc = 0;
 217
 218         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 219
 220         if (!dev->ops->dep_link_down)
 221                 return -EOPNOTSUPP;
 222
 223         device_lock(&dev->dev);
 224
 225         if (!device_is_registered(&dev->dev)) {
 226                 rc = -ENODEV;
 227                 goto error;
 228         }
 229
 230         if (dev->dep_link_up == false) {
 231                 rc = -EALREADY;
 232                 goto error;
 233         }
 234
 235         if (dev->dep_rf_mode == NFC_RF_TARGET) {
 236                 rc = -EOPNOTSUPP;
 237                 goto error;
 238         }
 239
 240         rc = dev->ops->dep_link_down(dev);
 241         if (!rc) {
 242                 dev->dep_link_up = false;
 243                 nfc_llcp_mac_is_down(dev);
 244                 nfc_genl_dep_link_down_event(dev);
 245         }
 246
 247 error:
 248         device_unlock(&dev->dev);
 249         return rc;
 250 }
 251
 252 int nfc_dep_link_is_up(struct nfc_dev *dev, u32 target_idx,
 253                                         u8 comm_mode, u8 rf_mode)
 254 {
 255         dev->dep_link_up = true;
 256         dev->dep_rf_mode = rf_mode;
 257
 258         nfc_llcp_mac_is_up(dev, target_idx, comm_mode, rf_mode);
 259
 260         return nfc_genl_dep_link_up_event(dev, target_idx, comm_mode, rf_mode);
 261 }
 262 EXPORT_SYMBOL(nfc_dep_link_is_up);
 263
 264 /**
 265  * nfc_activate_target - prepare the target for data exchange
 266  *
 267  * @dev: The nfc device that found the target
 268  * @target_idx: index of the target that must be activated
 269  * @protocol: nfc protocol that will be used for data exchange
 270  */
 271 int nfc_activate_target(struct nfc_dev *dev, u32 target_idx, u32 protocol)
 272 {
 273         int rc;
 274
 275         pr_debug("dev_name=%s target_idx=%u protocol=%u\n",
 276                  dev_name(&dev->dev), target_idx, protocol);
 277
 278         device_lock(&dev->dev);
 279
 280         if (!device_is_registered(&dev->dev)) {
 281                 rc = -ENODEV;
 282                 goto error;
 283         }
 284
 285         rc = dev->ops->activate_target(dev, target_idx, protocol);
 286         if (!rc)
 287                 dev->remote_activated = true;
 288
 289 error:
 290         device_unlock(&dev->dev);
 291         return rc;
 292 }
 293
 294 /**
 295  * nfc_deactivate_target - deactivate a nfc target
 296  *
 297  * @dev: The nfc device that found the target
 298  * @target_idx: index of the target that must be deactivated
 299  */
 300 int nfc_deactivate_target(struct nfc_dev *dev, u32 target_idx)
 301 {
 302         int rc = 0;
 303
 304         pr_debug("dev_name=%s target_idx=%u\n",
 305                  dev_name(&dev->dev), target_idx);
 306
 307         device_lock(&dev->dev);
 308
 309         if (!device_is_registered(&dev->dev)) {
 310                 rc = -ENODEV;
 311                 goto error;
 312         }
 313
 314         dev->ops->deactivate_target(dev, target_idx);
 315         dev->remote_activated = false;
 316
 317 error:
 318         device_unlock(&dev->dev);
 319         return rc;
 320 }
 321
 322 /**
 323  * nfc_data_exchange - transceive data
 324  *
 325  * @dev: The nfc device that found the target
 326  * @target_idx: index of the target
 327  * @skb: data to be sent
 328  * @cb: callback called when the response is received
 329  * @cb_context: parameter for the callback function
 330  *
 331  * The user must wait for the callback before calling this function again.
 332  */
 333 int nfc_data_exchange(struct nfc_dev *dev, u32 target_idx,
 334                                         struct sk_buff *skb,
 335                                         data_exchange_cb_t cb,
 336                                         void *cb_context)
 337 {
 338         int rc;
 339
 340         pr_debug("dev_name=%s target_idx=%u skb->len=%u\n",
 341                  dev_name(&dev->dev), target_idx, skb->len);
 342
 343         device_lock(&dev->dev);
 344
 345         if (!device_is_registered(&dev->dev)) {
 346                 rc = -ENODEV;
 347                 kfree_skb(skb);
 348                 goto error;
 349         }
 350
 351         rc = dev->ops->data_exchange(dev, target_idx, skb, cb, cb_context);
 352
 353 error:
 354         device_unlock(&dev->dev);
 355         return rc;
 356 }
 357
 358 int nfc_set_remote_general_bytes(struct nfc_dev *dev, u8 *gb, u8 gb_len)
 359 {
 360         pr_debug("dev_name=%s gb_len=%d\n",
 361                         dev_name(&dev->dev), gb_len);
 362
 363         if (gb_len > NFC_MAX_GT_LEN)
 364                 return -EINVAL;
 365
 366         return nfc_llcp_set_remote_gb(dev, gb, gb_len);
 367 }
 368 EXPORT_SYMBOL(nfc_set_remote_general_bytes);
 369
 370 u8 *nfc_get_local_general_bytes(struct nfc_dev *dev, u8 *gt_len)
 371 {
 372         return nfc_llcp_general_bytes(dev, gt_len);
 373 }
 374 EXPORT_SYMBOL(nfc_get_local_general_bytes);
 375
 376 /**
 377  * nfc_alloc_send_skb - allocate a skb for data exchange responses
 378  *
 379  * @size: size to allocate
 380  * @gfp: gfp flags
 381  */
 382 struct sk_buff *nfc_alloc_send_skb(struct nfc_dev *dev, struct sock *sk,
 383                                         unsigned int flags, unsigned int size,
 384                                         unsigned int *err)
 385 {
 386         struct sk_buff *skb;
 387         unsigned int total_size;
 388
 389         total_size = size +
 390                 dev->tx_headroom + dev->tx_tailroom + NFC_HEADER_SIZE;
 391
 392         skb = sock_alloc_send_skb(sk, total_size, flags & MSG_DONTWAIT, err);
 393         if (skb)
 394                 skb_reserve(skb, dev->tx_headroom + NFC_HEADER_SIZE);
 395
 396         return skb;
 397 }
 398
 399 /**
 400  * nfc_alloc_recv_skb - allocate a skb for data exchange responses
 401  *
 402  * @size: size to allocate
 403  * @gfp: gfp flags
 404  */
 405 struct sk_buff *nfc_alloc_recv_skb(unsigned int size, gfp_t gfp)
 406 {
 407         struct sk_buff *skb;
 408         unsigned int total_size;
 409
 410         total_size = size + 1;
 411         skb = alloc_skb(total_size, gfp);
 412
 413         if (skb)
 414                 skb_reserve(skb, 1);
 415
 416         return skb;
 417 }
 418 EXPORT_SYMBOL(nfc_alloc_recv_skb);
 419
 420 /**
 421  * nfc_targets_found - inform that targets were found
 422  *
 423  * @dev: The nfc device that found the targets
 424  * @targets: array of nfc targets found
 425  * @ntargets: targets array size
 426  *
 427  * The device driver must call this function when one or many nfc targets
 428  * are found. After calling this function, the device driver must stop
 429  * polling for targets.
 430  */
 431 int nfc_targets_found(struct nfc_dev *dev, struct nfc_target *targets,
 432                                                         int n_targets)
 433 {
 434         int i;
 435
 436         pr_debug("dev_name=%s n_targets=%d\n", dev_name(&dev->dev), n_targets);
 437
 438         dev->polling = false;
 439
 440         for (i = 0; i < n_targets; i++)
 441                 targets[i].idx = dev->target_idx++;
 442
 443         spin_lock_bh(&dev->targets_lock);
 444
 445         dev->targets_generation++;
 446
 447         kfree(dev->targets);
 448         dev->targets = kmemdup(targets, n_targets * sizeof(struct nfc_target),
 449                                                                 GFP_ATOMIC);
 450
 451         if (!dev->targets) {
 452                 dev->n_targets = 0;
 453                 spin_unlock_bh(&dev->targets_lock);
 454                 return -ENOMEM;
 455         }
 456
 457         dev->n_targets = n_targets;
 458         spin_unlock_bh(&dev->targets_lock);
 459
 460         nfc_genl_targets_found(dev);
 461
 462         return 0;
 463 }
 464 EXPORT_SYMBOL(nfc_targets_found);
 465
 466 static void nfc_release(struct device *d)
 467 {
 468         struct nfc_dev *dev = to_nfc_dev(d);
 469
 470         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 471
 472         nfc_genl_data_exit(&dev->genl_data);
 473         kfree(dev->targets);
 474         kfree(dev);
 475 }
 476
 477 struct class nfc_class = {
 478         .name = "nfc",
 479         .dev_release = nfc_release,
 480 };
 481 EXPORT_SYMBOL(nfc_class);
 482
 483 static int match_idx(struct device *d, void *data)
 484 {
 485         struct nfc_dev *dev = to_nfc_dev(d);
 486         unsigned *idx = data;
 487
 488         return dev->idx == *idx;
 489 }
 490
 491 struct nfc_dev *nfc_get_device(unsigned idx)
 492 {
 493         struct device *d;
 494
 495         d = class_find_device(&nfc_class, NULL, &idx, match_idx);
 496         if (!d)
 497                 return NULL;
 498
 499         return to_nfc_dev(d);
 500 }
 501
 502 /**
 503  * nfc_allocate_device - allocate a new nfc device
 504  *
 505  * @ops: device operations
 506  * @supported_protocols: NFC protocols supported by the device
 507  */
 508 struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops,
 509                                         u32 supported_protocols,
 510                                         int tx_headroom,
 511                                         int tx_tailroom)
 512 {
 513         static atomic_t dev_no = ATOMIC_INIT(0);
 514         struct nfc_dev *dev;
 515
 516         if (!ops->start_poll || !ops->stop_poll || !ops->activate_target ||
 517                 !ops->deactivate_target || !ops->data_exchange)
 518                 return NULL;
 519
 520         if (!supported_protocols)
 521                 return NULL;
 522
 523         dev = kzalloc(sizeof(struct nfc_dev), GFP_KERNEL);
 524         if (!dev)
 525                 return NULL;
 526
 527         dev->dev.class = &nfc_class;
 528         dev->idx = atomic_inc_return(&dev_no) - 1;
 529         dev_set_name(&dev->dev, "nfc%d", dev->idx);
 530         device_initialize(&dev->dev);
 531
 532         dev->ops = ops;
 533         dev->supported_protocols = supported_protocols;
 534         dev->tx_headroom = tx_headroom;
 535         dev->tx_tailroom = tx_tailroom;
 536
 537         spin_lock_init(&dev->targets_lock);
 538         nfc_genl_data_init(&dev->genl_data);
 539
 540         /* first generation must not be 0 */
 541         dev->targets_generation = 1;
 542
 543         return dev;
 544 }
 545 EXPORT_SYMBOL(nfc_allocate_device);
 546
 547 /**
 548  * nfc_register_device - register a nfc device in the nfc subsystem
 549  *
 550  * @dev: The nfc device to register
 551  */
 552 int nfc_register_device(struct nfc_dev *dev)
 553 {
 554         int rc;
 555
 556         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 557
 558         mutex_lock(&nfc_devlist_mutex);
 559         nfc_devlist_generation++;
 560         rc = device_add(&dev->dev);
 561         mutex_unlock(&nfc_devlist_mutex);
 562
 563         if (rc < 0)
 564                 return rc;
 565
 566         rc = nfc_llcp_register_device(dev);
 567         if (rc)
 568                 pr_err("Could not register llcp device\n");
 569
 570         rc = nfc_genl_device_added(dev);
 571         if (rc)
 572                 pr_debug("The userspace won't be notified that the device %s was added\n",
 573                          dev_name(&dev->dev));
 574
 575         return 0;
 576 }
 577 EXPORT_SYMBOL(nfc_register_device);
 578
 579 /**
 580  * nfc_unregister_device - unregister a nfc device in the nfc subsystem
 581  *
 582  * @dev: The nfc device to unregister
 583  */
 584 void nfc_unregister_device(struct nfc_dev *dev)
 585 {
 586         int rc;
 587
 588         pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 589
 590         mutex_lock(&nfc_devlist_mutex);
 591         nfc_devlist_generation++;
 592
 593         /* lock to avoid unregistering a device while an operation
 594            is in progress */
 595         device_lock(&dev->dev);
 596         device_del(&dev->dev);
 597         device_unlock(&dev->dev);
 598
 599         mutex_unlock(&nfc_devlist_mutex);
 600
 601         nfc_llcp_unregister_device(dev);
 602
 603         rc = nfc_genl_device_removed(dev);
 604         if (rc)
 605                 pr_debug("The userspace won't be notified that the device %s was removed\n",
 606                          dev_name(&dev->dev));
 607
 608 }
 609 EXPORT_SYMBOL(nfc_unregister_device);
 610
 611 static int __init nfc_init(void)
 612 {
 613         int rc;
 614
 615         pr_info("NFC Core ver %s\n", VERSION);
 616
 617         rc = class_register(&nfc_class);
 618         if (rc)
 619                 return rc;
 620
 621         rc = nfc_genl_init();
 622         if (rc)
 623                 goto err_genl;
 624
 625         /* the first generation must not be 0 */
 626         nfc_devlist_generation = 1;
 627
 628         rc = rawsock_init();
 629         if (rc)
 630                 goto err_rawsock;
 631
 632         rc = nfc_llcp_init();
 633         if (rc)
 634                 goto err_llcp_sock;
 635
 636         rc = af_nfc_init();
 637         if (rc)
 638                 goto err_af_nfc;
 639
 640         return 0;
 641
 642 err_af_nfc:
 643         nfc_llcp_exit();
 644 err_llcp_sock:
 645         rawsock_exit();
 646 err_rawsock:
 647         nfc_genl_exit();
 648 err_genl:
 649         class_unregister(&nfc_class);
 650         return rc;
 651 }
 652
 653 static void __exit nfc_exit(void)
 654 {
 655         af_nfc_exit();
 656         nfc_llcp_exit();
 657         rawsock_exit();
 658         nfc_genl_exit();
 659         class_unregister(&nfc_class);
 660 }
 661
 662 subsys_initcall(nfc_init);
 663 module_exit(nfc_exit);
 664
 665 MODULE_AUTHOR("Lauro Ramos Venancio <lauro.venancio@openbossa.org>");
 666 MODULE_DESCRIPTION("NFC Core ver " VERSION);
 667 MODULE_VERSION(VERSION);
 668 MODULE_LICENSE("GPL");