net/nfc/digital_dep.c

   1 /*
   2  * NFC Digital Protocol stack
   3  * Copyright (c) 2013, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  *
  14  */
  15
  16 #define pr_fmt(fmt) "digital: %s: " fmt, __func__
  17
  18 #include "digital.h"
  19
  20 #define DIGITAL_NFC_DEP_FRAME_DIR_OUT 0xD4
  21 #define DIGITAL_NFC_DEP_FRAME_DIR_IN  0xD5
  22
  23 #define DIGITAL_NFC_DEP_NFCA_SOD_SB   0xF0
  24
  25 #define DIGITAL_CMD_ATR_REQ 0x00
  26 #define DIGITAL_CMD_ATR_RES 0x01
  27 #define DIGITAL_CMD_PSL_REQ 0x04
  28 #define DIGITAL_CMD_PSL_RES 0x05
  29 #define DIGITAL_CMD_DEP_REQ 0x06
  30 #define DIGITAL_CMD_DEP_RES 0x07
  31
  32 #define DIGITAL_ATR_REQ_MIN_SIZE 16
  33 #define DIGITAL_ATR_REQ_MAX_SIZE 64
  34
  35 #define DIGITAL_LR_BITS_PAYLOAD_SIZE_254B 0x30
  36 #define DIGITAL_GB_BIT  0x02
  37
  38 #define DIGITAL_NFC_DEP_PFB_TYPE(pfb) ((pfb) & 0xE0)
  39
  40 #define DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT 0x10
  41
  42 #define DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb) \
  43                                 ((pfb) & DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT)
  44 #define DIGITAL_NFC_DEP_MI_BIT_SET(pfb)  ((pfb) & 0x10)
  45 #define DIGITAL_NFC_DEP_NAD_BIT_SET(pfb) ((pfb) & 0x08)
  46 #define DIGITAL_NFC_DEP_DID_BIT_SET(pfb) ((pfb) & 0x04)
  47 #define DIGITAL_NFC_DEP_PFB_PNI(pfb)     ((pfb) & 0x03)
  48
  49 #define DIGITAL_NFC_DEP_PFB_I_PDU          0x00
  50 #define DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU   0x40
  51 #define DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU 0x80
  52
  53 struct digital_atr_req {
  54         u8 dir;
  55         u8 cmd;
  56         u8 nfcid3[10];
  57         u8 did;
  58         u8 bs;
  59         u8 br;
  60         u8 pp;
  61         u8 gb[0];
  62 } __packed;
  63
  64 struct digital_atr_res {
  65         u8 dir;
  66         u8 cmd;
  67         u8 nfcid3[10];
  68         u8 did;
  69         u8 bs;
  70         u8 br;
  71         u8 to;
  72         u8 pp;
  73         u8 gb[0];
  74 } __packed;
  75
  76 struct digital_psl_req {
  77         u8 dir;
  78         u8 cmd;
  79         u8 did;
  80         u8 brs;
  81         u8 fsl;
  82 } __packed;
  83
  84 struct digital_psl_res {
  85         u8 dir;
  86         u8 cmd;
  87         u8 did;
  88 } __packed;
  89
  90 struct digital_dep_req_res {
  91         u8 dir;
  92         u8 cmd;
  93         u8 pfb;
  94 } __packed;
  95
  96 static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
  97                                     struct sk_buff *resp);
  98
  99 static void digital_skb_push_dep_sod(struct nfc_digital_dev *ddev,
 100                                      struct sk_buff *skb)
 101 {
 102         skb_push(skb, sizeof(u8));
 103
 104         skb->data[0] = skb->len;
 105
 106         if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
 107                 *skb_push(skb, sizeof(u8)) = DIGITAL_NFC_DEP_NFCA_SOD_SB;
 108 }
 109
 110 static int digital_skb_pull_dep_sod(struct nfc_digital_dev *ddev,
 111                                     struct sk_buff *skb)
 112 {
 113         u8 size;
 114
 115         if (skb->len < 2)
 116                 return -EIO;
 117
 118         if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
 119                 skb_pull(skb, sizeof(u8));
 120
 121         size = skb->data[0];
 122         if (size != skb->len)
 123                 return -EIO;
 124
 125         skb_pull(skb, sizeof(u8));
 126
 127         return 0;
 128 }
 129
 130 static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg,
 131                                  struct sk_buff *resp)
 132 {
 133         struct nfc_target *target = arg;
 134         struct digital_atr_res *atr_res;
 135         u8 gb_len;
 136         int rc;
 137
 138         if (IS_ERR(resp)) {
 139                 rc = PTR_ERR(resp);
 140                 resp = NULL;
 141                 goto exit;
 142         }
 143
 144         rc = ddev->skb_check_crc(resp);
 145         if (rc) {
 146                 PROTOCOL_ERR("14.4.1.6");
 147                 goto exit;
 148         }
 149
 150         rc = digital_skb_pull_dep_sod(ddev, resp);
 151         if (rc) {
 152                 PROTOCOL_ERR("14.4.1.2");
 153                 goto exit;
 154         }
 155
 156         if (resp->len < sizeof(struct digital_atr_res)) {
 157                 rc = -EIO;
 158                 goto exit;
 159         }
 160
 161         gb_len = resp->len - sizeof(struct digital_atr_res);
 162
 163         atr_res = (struct digital_atr_res *)resp->data;
 164
 165         rc = nfc_set_remote_general_bytes(ddev->nfc_dev, atr_res->gb, gb_len);
 166         if (rc)
 167                 goto exit;
 168
 169         rc = nfc_dep_link_is_up(ddev->nfc_dev, target->idx, NFC_COMM_ACTIVE,
 170                                 NFC_RF_INITIATOR);
 171
 172         ddev->curr_nfc_dep_pni = 0;
 173
 174 exit:
 175         dev_kfree_skb(resp);
 176
 177         if (rc)
 178                 ddev->curr_protocol = 0;
 179 }
 180
 181 int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
 182                             struct nfc_target *target, __u8 comm_mode, __u8 *gb,
 183                             size_t gb_len)
 184 {
 185         struct sk_buff *skb;
 186         struct digital_atr_req *atr_req;
 187         uint size;
 188
 189         size = DIGITAL_ATR_REQ_MIN_SIZE + gb_len;
 190
 191         if (size > DIGITAL_ATR_REQ_MAX_SIZE) {
 192                 PROTOCOL_ERR("14.6.1.1");
 193                 return -EINVAL;
 194         }
 195
 196         skb = digital_skb_alloc(ddev, size);
 197         if (!skb)
 198                 return -ENOMEM;
 199
 200         skb_put(skb, sizeof(struct digital_atr_req));
 201
 202         atr_req = (struct digital_atr_req *)skb->data;
 203         memset(atr_req, 0, sizeof(struct digital_atr_req));
 204
 205         atr_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
 206         atr_req->cmd = DIGITAL_CMD_ATR_REQ;
 207         if (target->nfcid2_len)
 208                 memcpy(atr_req->nfcid3, target->nfcid2, NFC_NFCID2_MAXSIZE);
 209         else
 210                 get_random_bytes(atr_req->nfcid3, NFC_NFCID3_MAXSIZE);
 211
 212         atr_req->did = 0;
 213         atr_req->bs = 0;
 214         atr_req->br = 0;
 215
 216         atr_req->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
 217
 218         if (gb_len) {
 219                 atr_req->pp |= DIGITAL_GB_BIT;
 220                 memcpy(skb_put(skb, gb_len), gb, gb_len);
 221         }
 222
 223         digital_skb_push_dep_sod(ddev, skb);
 224
 225         ddev->skb_add_crc(skb);
 226
 227         digital_in_send_cmd(ddev, skb, 500, digital_in_recv_atr_res, target);
 228
 229         return 0;
 230 }
 231
 232 static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
 233                                 struct digital_data_exch *data_exch, u8 rtox)
 234 {
 235         struct digital_dep_req_res *dep_req;
 236         struct sk_buff *skb;
 237         int rc;
 238
 239         skb = digital_skb_alloc(ddev, 1);
 240         if (!skb)
 241                 return -ENOMEM;
 242
 243         *skb_put(skb, 1) = rtox;
 244
 245         skb_push(skb, sizeof(struct digital_dep_req_res));
 246
 247         dep_req = (struct digital_dep_req_res *)skb->data;
 248
 249         dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
 250         dep_req->cmd = DIGITAL_CMD_DEP_REQ;
 251         dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU |
 252                        DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT;
 253
 254         digital_skb_push_dep_sod(ddev, skb);
 255
 256         ddev->skb_add_crc(skb);
 257
 258         rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
 259                                  data_exch);
 260
 261         return rc;
 262 }
 263
 264 static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 265                                     struct sk_buff *resp)
 266 {
 267         struct digital_data_exch *data_exch = arg;
 268         struct digital_dep_req_res *dep_res;
 269         u8 pfb;
 270         uint size;
 271         int rc;
 272
 273         if (IS_ERR(resp)) {
 274                 rc = PTR_ERR(resp);
 275                 resp = NULL;
 276                 goto exit;
 277         }
 278
 279         rc = ddev->skb_check_crc(resp);
 280         if (rc) {
 281                 PROTOCOL_ERR("14.4.1.6");
 282                 goto error;
 283         }
 284
 285         rc = digital_skb_pull_dep_sod(ddev, resp);
 286         if (rc) {
 287                 PROTOCOL_ERR("14.4.1.2");
 288                 goto exit;
 289         }
 290
 291         dep_res = (struct digital_dep_req_res *)resp->data;
 292
 293         if (resp->len < sizeof(struct digital_dep_req_res) ||
 294             dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||
 295             dep_res->cmd != DIGITAL_CMD_DEP_RES) {
 296                 rc = -EIO;
 297                 goto error;
 298         }
 299
 300         pfb = dep_res->pfb;
 301
 302         switch (DIGITAL_NFC_DEP_PFB_TYPE(pfb)) {
 303         case DIGITAL_NFC_DEP_PFB_I_PDU:
 304                 if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
 305                         PROTOCOL_ERR("14.12.3.3");
 306                         rc = -EIO;
 307                         goto error;
 308                 }
 309
 310                 ddev->curr_nfc_dep_pni =
 311                         DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);
 312                 rc = 0;
 313                 break;
 314
 315         case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
 316                 pr_err("Received a ACK/NACK PDU\n");
 317                 rc = -EIO;
 318                 goto error;
 319
 320         case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
 321                 if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
 322                         rc = -EINVAL;
 323                         goto error;
 324                 }
 325
 326                 rc = digital_in_send_rtox(ddev, data_exch, resp->data[3]);
 327                 if (rc)
 328                         goto error;
 329
 330                 kfree_skb(resp);
 331                 return;
 332         }
 333
 334         if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb)) {
 335                 pr_err("MI bit set. Chained PDU not supported\n");
 336                 rc = -EIO;
 337                 goto error;
 338         }
 339
 340         size = sizeof(struct digital_dep_req_res);
 341
 342         if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb))
 343                 size++;
 344
 345         if (size > resp->len) {
 346                 rc = -EIO;
 347                 goto error;
 348         }
 349
 350         skb_pull(resp, size);
 351
 352 exit:
 353         data_exch->cb(data_exch->cb_context, resp, rc);
 354
 355 error:
 356         kfree(data_exch);
 357
 358         if (rc)
 359                 kfree_skb(resp);
 360 }
 361
 362 int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
 363                             struct nfc_target *target, struct sk_buff *skb,
 364                             struct digital_data_exch *data_exch)
 365 {
 366         struct digital_dep_req_res *dep_req;
 367
 368         skb_push(skb, sizeof(struct digital_dep_req_res));
 369
 370         dep_req = (struct digital_dep_req_res *)skb->data;
 371         dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
 372         dep_req->cmd = DIGITAL_CMD_DEP_REQ;
 373         dep_req->pfb = ddev->curr_nfc_dep_pni;
 374
 375         digital_skb_push_dep_sod(ddev, skb);
 376
 377         ddev->skb_add_crc(skb);
 378
 379         return digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
 380                                    data_exch);
 381 }
 382
 383 static void digital_tg_set_rf_tech(struct nfc_digital_dev *ddev, u8 rf_tech)
 384 {
 385         ddev->curr_rf_tech = rf_tech;
 386
 387         ddev->skb_add_crc = digital_skb_add_crc_none;
 388         ddev->skb_check_crc = digital_skb_check_crc_none;
 389
 390         if (DIGITAL_DRV_CAPS_TG_CRC(ddev))
 391                 return;
 392
 393         switch (ddev->curr_rf_tech) {
 394         case NFC_DIGITAL_RF_TECH_106A:
 395                 ddev->skb_add_crc = digital_skb_add_crc_a;
 396                 ddev->skb_check_crc = digital_skb_check_crc_a;
 397                 break;
 398
 399         case NFC_DIGITAL_RF_TECH_212F:
 400         case NFC_DIGITAL_RF_TECH_424F:
 401                 ddev->skb_add_crc = digital_skb_add_crc_f;
 402                 ddev->skb_check_crc = digital_skb_check_crc_f;
 403                 break;
 404
 405         default:
 406                 break;
 407         }
 408 }
 409
 410 static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
 411                                     struct sk_buff *resp)
 412 {
 413         int rc;
 414         struct digital_dep_req_res *dep_req;
 415         size_t size;
 416
 417         if (IS_ERR(resp)) {
 418                 rc = PTR_ERR(resp);
 419                 resp = NULL;
 420                 goto exit;
 421         }
 422
 423         rc = ddev->skb_check_crc(resp);
 424         if (rc) {
 425                 PROTOCOL_ERR("14.4.1.6");
 426                 goto exit;
 427         }
 428
 429         rc = digital_skb_pull_dep_sod(ddev, resp);
 430         if (rc) {
 431                 PROTOCOL_ERR("14.4.1.2");
 432                 goto exit;
 433         }
 434
 435         size = sizeof(struct digital_dep_req_res);
 436         dep_req = (struct digital_dep_req_res *)resp->data;
 437
 438         if (resp->len < size || dep_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
 439             dep_req->cmd != DIGITAL_CMD_DEP_REQ) {
 440                 rc = -EIO;
 441                 goto exit;
 442         }
 443
 444         if (DIGITAL_NFC_DEP_DID_BIT_SET(dep_req->pfb))
 445                 size++;
 446
 447         if (resp->len < size) {
 448                 rc = -EIO;
 449                 goto exit;
 450         }
 451
 452         switch (DIGITAL_NFC_DEP_PFB_TYPE(dep_req->pfb)) {
 453         case DIGITAL_NFC_DEP_PFB_I_PDU:
 454                 pr_debug("DIGITAL_NFC_DEP_PFB_I_PDU\n");
 455                 ddev->curr_nfc_dep_pni = DIGITAL_NFC_DEP_PFB_PNI(dep_req->pfb);
 456                 break;
 457         case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
 458                 pr_err("Received a ACK/NACK PDU\n");
 459                 rc = -EINVAL;
 460                 goto exit;
 461                 break;
 462         case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
 463                 pr_err("Received a SUPERVISOR PDU\n");
 464                 rc = -EINVAL;
 465                 goto exit;
 466                 break;
 467         }
 468
 469         skb_pull(resp, size);
 470
 471         rc = nfc_tm_data_received(ddev->nfc_dev, resp);
 472
 473 exit:
 474         if (rc)
 475                 kfree_skb(resp);
 476 }
 477
 478 int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb)
 479 {
 480         struct digital_dep_req_res *dep_res;
 481
 482         skb_push(skb, sizeof(struct digital_dep_req_res));
 483         dep_res = (struct digital_dep_req_res *)skb->data;
 484
 485         dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
 486         dep_res->cmd = DIGITAL_CMD_DEP_RES;
 487         dep_res->pfb = ddev->curr_nfc_dep_pni;
 488
 489         digital_skb_push_dep_sod(ddev, skb);
 490
 491         ddev->skb_add_crc(skb);
 492
 493         return digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
 494                                    NULL);
 495 }
 496
 497 static void digital_tg_send_psl_res_complete(struct nfc_digital_dev *ddev,
 498                                              void *arg, struct sk_buff *resp)
 499 {
 500         u8 rf_tech = (unsigned long)arg;
 501
 502         if (IS_ERR(resp))
 503                 return;
 504
 505         digital_tg_set_rf_tech(ddev, rf_tech);
 506
 507         digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH, rf_tech);
 508
 509         digital_tg_listen(ddev, 1500, digital_tg_recv_dep_req, NULL);
 510
 511         dev_kfree_skb(resp);
 512 }
 513
 514 static int digital_tg_send_psl_res(struct nfc_digital_dev *ddev, u8 did,
 515                                    u8 rf_tech)
 516 {
 517         struct digital_psl_res *psl_res;
 518         struct sk_buff *skb;
 519         int rc;
 520
 521         skb = digital_skb_alloc(ddev, sizeof(struct digital_psl_res));
 522         if (!skb)
 523                 return -ENOMEM;
 524
 525         skb_put(skb, sizeof(struct digital_psl_res));
 526
 527         psl_res = (struct digital_psl_res *)skb->data;
 528
 529         psl_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
 530         psl_res->cmd = DIGITAL_CMD_PSL_RES;
 531         psl_res->did = did;
 532
 533         digital_skb_push_dep_sod(ddev, skb);
 534
 535         ddev->skb_add_crc(skb);
 536
 537         rc = digital_tg_send_cmd(ddev, skb, 0, digital_tg_send_psl_res_complete,
 538                                  (void *)(unsigned long)rf_tech);
 539
 540         if (rc)
 541                 kfree_skb(skb);
 542
 543         return rc;
 544 }
 545
 546 static void digital_tg_recv_psl_req(struct nfc_digital_dev *ddev, void *arg,
 547                                     struct sk_buff *resp)
 548 {
 549         int rc;
 550         struct digital_psl_req *psl_req;
 551         u8 rf_tech;
 552         u8 dsi;
 553
 554         if (IS_ERR(resp)) {
 555                 rc = PTR_ERR(resp);
 556                 resp = NULL;
 557                 goto exit;
 558         }
 559
 560         rc = ddev->skb_check_crc(resp);
 561         if (rc) {
 562                 PROTOCOL_ERR("14.4.1.6");
 563                 goto exit;
 564         }
 565
 566         rc = digital_skb_pull_dep_sod(ddev, resp);
 567         if (rc) {
 568                 PROTOCOL_ERR("14.4.1.2");
 569                 goto exit;
 570         }
 571
 572         psl_req = (struct digital_psl_req *)resp->data;
 573
 574         if (resp->len != sizeof(struct digital_psl_req) ||
 575             psl_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
 576             psl_req->cmd != DIGITAL_CMD_PSL_REQ) {
 577                 rc = -EIO;
 578                 goto exit;
 579         }
 580
 581         dsi = (psl_req->brs >> 3) & 0x07;
 582         switch (dsi) {
 583         case 0:
 584                 rf_tech = NFC_DIGITAL_RF_TECH_106A;
 585                 break;
 586         case 1:
 587                 rf_tech = NFC_DIGITAL_RF_TECH_212F;
 588                 break;
 589         case 2:
 590                 rf_tech = NFC_DIGITAL_RF_TECH_424F;
 591                 break;
 592         default:
 593                 pr_err("Unsupported dsi value %d\n", dsi);
 594                 goto exit;
 595         }
 596
 597         rc = digital_tg_send_psl_res(ddev, psl_req->did, rf_tech);
 598
 599 exit:
 600         kfree_skb(resp);
 601 }
 602
 603 static void digital_tg_send_atr_res_complete(struct nfc_digital_dev *ddev,
 604                                              void *arg, struct sk_buff *resp)
 605 {
 606         int offset;
 607
 608         if (IS_ERR(resp)) {
 609                 digital_poll_next_tech(ddev);
 610                 return;
 611         }
 612
 613         offset = 2;
 614         if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB)
 615                 offset++;
 616
 617         if (resp->data[offset] == DIGITAL_CMD_PSL_REQ)
 618                 digital_tg_recv_psl_req(ddev, arg, resp);
 619         else
 620                 digital_tg_recv_dep_req(ddev, arg, resp);
 621 }
 622
 623 static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
 624                                    struct digital_atr_req *atr_req)
 625 {
 626         struct digital_atr_res *atr_res;
 627         struct sk_buff *skb;
 628         u8 *gb;
 629         size_t gb_len;
 630         int rc;
 631
 632         gb = nfc_get_local_general_bytes(ddev->nfc_dev, &gb_len);
 633         if (!gb)
 634                 gb_len = 0;
 635
 636         skb = digital_skb_alloc(ddev, sizeof(struct digital_atr_res) + gb_len);
 637         if (!skb)
 638                 return -ENOMEM;
 639
 640         skb_put(skb, sizeof(struct digital_atr_res));
 641         atr_res = (struct digital_atr_res *)skb->data;
 642
 643         memset(atr_res, 0, sizeof(struct digital_atr_res));
 644
 645         atr_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
 646         atr_res->cmd = DIGITAL_CMD_ATR_RES;
 647         memcpy(atr_res->nfcid3, atr_req->nfcid3, sizeof(atr_req->nfcid3));
 648         atr_res->to = 8;
 649         atr_res->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
 650         if (gb_len) {
 651                 skb_put(skb, gb_len);
 652
 653                 atr_res->pp |= DIGITAL_GB_BIT;
 654                 memcpy(atr_res->gb, gb, gb_len);
 655         }
 656
 657         digital_skb_push_dep_sod(ddev, skb);
 658
 659         ddev->skb_add_crc(skb);
 660
 661         rc = digital_tg_send_cmd(ddev, skb, 999,
 662                                  digital_tg_send_atr_res_complete, NULL);
 663         if (rc) {
 664                 kfree_skb(skb);
 665                 return rc;
 666         }
 667
 668         return rc;
 669 }
 670
 671 void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg,
 672                              struct sk_buff *resp)
 673 {
 674         int rc;
 675         struct digital_atr_req *atr_req;
 676         size_t gb_len, min_size;
 677
 678         if (IS_ERR(resp)) {
 679                 rc = PTR_ERR(resp);
 680                 resp = NULL;
 681                 goto exit;
 682         }
 683
 684         if (!resp->len) {
 685                 rc = -EIO;
 686                 goto exit;
 687         }
 688
 689         if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB) {
 690                 min_size = DIGITAL_ATR_REQ_MIN_SIZE + 2;
 691                 digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_106A);
 692         } else {
 693                 min_size = DIGITAL_ATR_REQ_MIN_SIZE + 1;
 694                 digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_212F);
 695         }
 696
 697         if (resp->len < min_size) {
 698                 rc = -EIO;
 699                 goto exit;
 700         }
 701
 702         ddev->curr_protocol = NFC_PROTO_NFC_DEP_MASK;
 703
 704         rc = ddev->skb_check_crc(resp);
 705         if (rc) {
 706                 PROTOCOL_ERR("14.4.1.6");
 707                 goto exit;
 708         }
 709
 710         rc = digital_skb_pull_dep_sod(ddev, resp);
 711         if (rc) {
 712                 PROTOCOL_ERR("14.4.1.2");
 713                 goto exit;
 714         }
 715
 716         atr_req = (struct digital_atr_req *)resp->data;
 717
 718         if (atr_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
 719             atr_req->cmd != DIGITAL_CMD_ATR_REQ) {
 720                 rc = -EINVAL;
 721                 goto exit;
 722         }
 723
 724         rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
 725                                      NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED);
 726         if (rc)
 727                 goto exit;
 728
 729         rc = digital_tg_send_atr_res(ddev, atr_req);
 730         if (rc)
 731                 goto exit;
 732
 733         gb_len = resp->len - sizeof(struct digital_atr_req);
 734         rc = nfc_tm_activated(ddev->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
 735                               NFC_COMM_PASSIVE, atr_req->gb, gb_len);
 736         if (rc)
 737                 goto exit;
 738
 739         ddev->poll_tech_count = 0;
 740
 741         rc = 0;
 742 exit:
 743         if (rc)
 744                 digital_poll_next_tech(ddev);
 745
 746         dev_kfree_skb(resp);
 747 }