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         return digital_in_send_cmd(ddev, skb, 500, digital_in_recv_atr_res,
 228                                    target);
 229 }
 230
 231 static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
 232                                 struct digital_data_exch *data_exch, u8 rtox)
 233 {
 234         struct digital_dep_req_res *dep_req;
 235         struct sk_buff *skb;
 236         int rc;
 237
 238         skb = digital_skb_alloc(ddev, 1);
 239         if (!skb)
 240                 return -ENOMEM;
 241
 242         *skb_put(skb, 1) = rtox;
 243
 244         skb_push(skb, sizeof(struct digital_dep_req_res));
 245
 246         dep_req = (struct digital_dep_req_res *)skb->data;
 247
 248         dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
 249         dep_req->cmd = DIGITAL_CMD_DEP_REQ;
 250         dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU |
 251                        DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT;
 252
 253         digital_skb_push_dep_sod(ddev, skb);
 254
 255         ddev->skb_add_crc(skb);
 256
 257         rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
 258                                  data_exch);
 259
 260         return rc;
 261 }
 262
 263 static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
 264                                     struct sk_buff *resp)
 265 {
 266         struct digital_data_exch *data_exch = arg;
 267         struct digital_dep_req_res *dep_res;
 268         u8 pfb;
 269         uint size;
 270         int rc;
 271
 272         if (IS_ERR(resp)) {
 273                 rc = PTR_ERR(resp);
 274                 resp = NULL;
 275                 goto exit;
 276         }
 277
 278         rc = ddev->skb_check_crc(resp);
 279         if (rc) {
 280                 PROTOCOL_ERR("14.4.1.6");
 281                 goto error;
 282         }
 283
 284         rc = digital_skb_pull_dep_sod(ddev, resp);
 285         if (rc) {
 286                 PROTOCOL_ERR("14.4.1.2");
 287                 goto exit;
 288         }
 289
 290         dep_res = (struct digital_dep_req_res *)resp->data;
 291
 292         if (resp->len < sizeof(struct digital_dep_req_res) ||
 293             dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||
 294             dep_res->cmd != DIGITAL_CMD_DEP_RES) {
 295                 rc = -EIO;
 296                 goto error;
 297         }
 298
 299         pfb = dep_res->pfb;
 300
 301         switch (DIGITAL_NFC_DEP_PFB_TYPE(pfb)) {
 302         case DIGITAL_NFC_DEP_PFB_I_PDU:
 303                 if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
 304                         PROTOCOL_ERR("14.12.3.3");
 305                         rc = -EIO;
 306                         goto error;
 307                 }
 308
 309                 ddev->curr_nfc_dep_pni =
 310                         DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);
 311                 rc = 0;
 312                 break;
 313
 314         case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
 315                 pr_err("Received a ACK/NACK PDU\n");
 316                 rc = -EIO;
 317                 goto error;
 318
 319         case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
 320                 if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
 321                         rc = -EINVAL;
 322                         goto error;
 323                 }
 324
 325                 rc = digital_in_send_rtox(ddev, data_exch, resp->data[3]);
 326                 if (rc)
 327                         goto error;
 328
 329                 kfree_skb(resp);
 330                 return;
 331         }
 332
 333         if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb)) {
 334                 pr_err("MI bit set. Chained PDU not supported\n");
 335                 rc = -EIO;
 336                 goto error;
 337         }
 338
 339         size = sizeof(struct digital_dep_req_res);
 340
 341         if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb))
 342                 size++;
 343
 344         if (size > resp->len) {
 345                 rc = -EIO;
 346                 goto error;
 347         }
 348
 349         skb_pull(resp, size);
 350
 351 exit:
 352         data_exch->cb(data_exch->cb_context, resp, rc);
 353
 354 error:
 355         kfree(data_exch);
 356
 357         if (rc)
 358                 kfree_skb(resp);
 359 }
 360
 361 int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
 362                             struct nfc_target *target, struct sk_buff *skb,
 363                             struct digital_data_exch *data_exch)
 364 {
 365         struct digital_dep_req_res *dep_req;
 366
 367         skb_push(skb, sizeof(struct digital_dep_req_res));
 368
 369         dep_req = (struct digital_dep_req_res *)skb->data;
 370         dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
 371         dep_req->cmd = DIGITAL_CMD_DEP_REQ;
 372         dep_req->pfb = ddev->curr_nfc_dep_pni;
 373
 374         digital_skb_push_dep_sod(ddev, skb);
 375
 376         ddev->skb_add_crc(skb);
 377
 378         return digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
 379                                    data_exch);
 380 }
 381
 382 static void digital_tg_set_rf_tech(struct nfc_digital_dev *ddev, u8 rf_tech)
 383 {
 384         ddev->curr_rf_tech = rf_tech;
 385
 386         ddev->skb_add_crc = digital_skb_add_crc_none;
 387         ddev->skb_check_crc = digital_skb_check_crc_none;
 388
 389         if (DIGITAL_DRV_CAPS_TG_CRC(ddev))
 390                 return;
 391
 392         switch (ddev->curr_rf_tech) {
 393         case NFC_DIGITAL_RF_TECH_106A:
 394                 ddev->skb_add_crc = digital_skb_add_crc_a;
 395                 ddev->skb_check_crc = digital_skb_check_crc_a;
 396                 break;
 397
 398         case NFC_DIGITAL_RF_TECH_212F:
 399         case NFC_DIGITAL_RF_TECH_424F:
 400                 ddev->skb_add_crc = digital_skb_add_crc_f;
 401                 ddev->skb_check_crc = digital_skb_check_crc_f;
 402                 break;
 403
 404         default:
 405                 break;
 406         }
 407 }
 408
 409 static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
 410                                     struct sk_buff *resp)
 411 {
 412         int rc;
 413         struct digital_dep_req_res *dep_req;
 414         size_t size;
 415
 416         if (IS_ERR(resp)) {
 417                 rc = PTR_ERR(resp);
 418                 resp = NULL;
 419                 goto exit;
 420         }
 421
 422         rc = ddev->skb_check_crc(resp);
 423         if (rc) {
 424                 PROTOCOL_ERR("14.4.1.6");
 425                 goto exit;
 426         }
 427
 428         rc = digital_skb_pull_dep_sod(ddev, resp);
 429         if (rc) {
 430                 PROTOCOL_ERR("14.4.1.2");
 431                 goto exit;
 432         }
 433
 434         size = sizeof(struct digital_dep_req_res);
 435         dep_req = (struct digital_dep_req_res *)resp->data;
 436
 437         if (resp->len < size || dep_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
 438             dep_req->cmd != DIGITAL_CMD_DEP_REQ) {
 439                 rc = -EIO;
 440                 goto exit;
 441         }
 442
 443         if (DIGITAL_NFC_DEP_DID_BIT_SET(dep_req->pfb))
 444                 size++;
 445
 446         if (resp->len < size) {
 447                 rc = -EIO;
 448                 goto exit;
 449         }
 450
 451         switch (DIGITAL_NFC_DEP_PFB_TYPE(dep_req->pfb)) {
 452         case DIGITAL_NFC_DEP_PFB_I_PDU:
 453                 pr_debug("DIGITAL_NFC_DEP_PFB_I_PDU\n");
 454                 ddev->curr_nfc_dep_pni = DIGITAL_NFC_DEP_PFB_PNI(dep_req->pfb);
 455                 break;
 456         case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
 457                 pr_err("Received a ACK/NACK PDU\n");
 458                 rc = -EINVAL;
 459                 goto exit;
 460                 break;
 461         case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
 462                 pr_err("Received a SUPERVISOR PDU\n");
 463                 rc = -EINVAL;
 464                 goto exit;
 465                 break;
 466         }
 467
 468         skb_pull(resp, size);
 469
 470         rc = nfc_tm_data_received(ddev->nfc_dev, resp);
 471
 472 exit:
 473         if (rc)
 474                 kfree_skb(resp);
 475 }
 476
 477 int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb)
 478 {
 479         struct digital_dep_req_res *dep_res;
 480
 481         skb_push(skb, sizeof(struct digital_dep_req_res));
 482         dep_res = (struct digital_dep_req_res *)skb->data;
 483
 484         dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
 485         dep_res->cmd = DIGITAL_CMD_DEP_RES;
 486         dep_res->pfb = ddev->curr_nfc_dep_pni;
 487
 488         digital_skb_push_dep_sod(ddev, skb);
 489
 490         ddev->skb_add_crc(skb);
 491
 492         return digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
 493                                    NULL);
 494 }
 495
 496 static void digital_tg_send_psl_res_complete(struct nfc_digital_dev *ddev,
 497                                              void *arg, struct sk_buff *resp)
 498 {
 499         u8 rf_tech = (unsigned long)arg;
 500
 501         if (IS_ERR(resp))
 502                 return;
 503
 504         digital_tg_set_rf_tech(ddev, rf_tech);
 505
 506         digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH, rf_tech);
 507
 508         digital_tg_listen(ddev, 1500, digital_tg_recv_dep_req, NULL);
 509
 510         dev_kfree_skb(resp);
 511 }
 512
 513 static int digital_tg_send_psl_res(struct nfc_digital_dev *ddev, u8 did,
 514                                    u8 rf_tech)
 515 {
 516         struct digital_psl_res *psl_res;
 517         struct sk_buff *skb;
 518         int rc;
 519
 520         skb = digital_skb_alloc(ddev, sizeof(struct digital_psl_res));
 521         if (!skb)
 522                 return -ENOMEM;
 523
 524         skb_put(skb, sizeof(struct digital_psl_res));
 525
 526         psl_res = (struct digital_psl_res *)skb->data;
 527
 528         psl_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
 529         psl_res->cmd = DIGITAL_CMD_PSL_RES;
 530         psl_res->did = did;
 531
 532         digital_skb_push_dep_sod(ddev, skb);
 533
 534         ddev->skb_add_crc(skb);
 535
 536         rc = digital_tg_send_cmd(ddev, skb, 0, digital_tg_send_psl_res_complete,
 537                                  (void *)(unsigned long)rf_tech);
 538
 539         if (rc)
 540                 kfree_skb(skb);
 541
 542         return rc;
 543 }
 544
 545 static void digital_tg_recv_psl_req(struct nfc_digital_dev *ddev, void *arg,
 546                                     struct sk_buff *resp)
 547 {
 548         int rc;
 549         struct digital_psl_req *psl_req;
 550         u8 rf_tech;
 551         u8 dsi;
 552
 553         if (IS_ERR(resp)) {
 554                 rc = PTR_ERR(resp);
 555                 resp = NULL;
 556                 goto exit;
 557         }
 558
 559         rc = ddev->skb_check_crc(resp);
 560         if (rc) {
 561                 PROTOCOL_ERR("14.4.1.6");
 562                 goto exit;
 563         }
 564
 565         rc = digital_skb_pull_dep_sod(ddev, resp);
 566         if (rc) {
 567                 PROTOCOL_ERR("14.4.1.2");
 568                 goto exit;
 569         }
 570
 571         psl_req = (struct digital_psl_req *)resp->data;
 572
 573         if (resp->len != sizeof(struct digital_psl_req) ||
 574             psl_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
 575             psl_req->cmd != DIGITAL_CMD_PSL_REQ) {
 576                 rc = -EIO;
 577                 goto exit;
 578         }
 579
 580         dsi = (psl_req->brs >> 3) & 0x07;
 581         switch (dsi) {
 582         case 0:
 583                 rf_tech = NFC_DIGITAL_RF_TECH_106A;
 584                 break;
 585         case 1:
 586                 rf_tech = NFC_DIGITAL_RF_TECH_212F;
 587                 break;
 588         case 2:
 589                 rf_tech = NFC_DIGITAL_RF_TECH_424F;
 590                 break;
 591         default:
 592                 pr_err("Unsupported dsi value %d\n", dsi);
 593                 goto exit;
 594         }
 595
 596         rc = digital_tg_send_psl_res(ddev, psl_req->did, rf_tech);
 597
 598 exit:
 599         kfree_skb(resp);
 600 }
 601
 602 static void digital_tg_send_atr_res_complete(struct nfc_digital_dev *ddev,
 603                                              void *arg, struct sk_buff *resp)
 604 {
 605         int offset;
 606
 607         if (IS_ERR(resp)) {
 608                 digital_poll_next_tech(ddev);
 609                 return;
 610         }
 611
 612         offset = 2;
 613         if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB)
 614                 offset++;
 615
 616         if (resp->data[offset] == DIGITAL_CMD_PSL_REQ)
 617                 digital_tg_recv_psl_req(ddev, arg, resp);
 618         else
 619                 digital_tg_recv_dep_req(ddev, arg, resp);
 620 }
 621
 622 static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
 623                                    struct digital_atr_req *atr_req)
 624 {
 625         struct digital_atr_res *atr_res;
 626         struct sk_buff *skb;
 627         u8 *gb;
 628         size_t gb_len;
 629         int rc;
 630
 631         gb = nfc_get_local_general_bytes(ddev->nfc_dev, &gb_len);
 632         if (!gb)
 633                 gb_len = 0;
 634
 635         skb = digital_skb_alloc(ddev, sizeof(struct digital_atr_res) + gb_len);
 636         if (!skb)
 637                 return -ENOMEM;
 638
 639         skb_put(skb, sizeof(struct digital_atr_res));
 640         atr_res = (struct digital_atr_res *)skb->data;
 641
 642         memset(atr_res, 0, sizeof(struct digital_atr_res));
 643
 644         atr_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
 645         atr_res->cmd = DIGITAL_CMD_ATR_RES;
 646         memcpy(atr_res->nfcid3, atr_req->nfcid3, sizeof(atr_req->nfcid3));
 647         atr_res->to = 8;
 648         atr_res->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
 649         if (gb_len) {
 650                 skb_put(skb, gb_len);
 651
 652                 atr_res->pp |= DIGITAL_GB_BIT;
 653                 memcpy(atr_res->gb, gb, gb_len);
 654         }
 655
 656         digital_skb_push_dep_sod(ddev, skb);
 657
 658         ddev->skb_add_crc(skb);
 659
 660         rc = digital_tg_send_cmd(ddev, skb, 999,
 661                                  digital_tg_send_atr_res_complete, NULL);
 662         if (rc) {
 663                 kfree_skb(skb);
 664                 return rc;
 665         }
 666
 667         return rc;
 668 }
 669
 670 void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg,
 671                              struct sk_buff *resp)
 672 {
 673         int rc;
 674         struct digital_atr_req *atr_req;
 675         size_t gb_len, min_size;
 676
 677         if (IS_ERR(resp)) {
 678                 rc = PTR_ERR(resp);
 679                 resp = NULL;
 680                 goto exit;
 681         }
 682
 683         if (!resp->len) {
 684                 rc = -EIO;
 685                 goto exit;
 686         }
 687
 688         if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB) {
 689                 min_size = DIGITAL_ATR_REQ_MIN_SIZE + 2;
 690                 digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_106A);
 691         } else {
 692                 min_size = DIGITAL_ATR_REQ_MIN_SIZE + 1;
 693                 digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_212F);
 694         }
 695
 696         if (resp->len < min_size) {
 697                 rc = -EIO;
 698                 goto exit;
 699         }
 700
 701         ddev->curr_protocol = NFC_PROTO_NFC_DEP_MASK;
 702
 703         rc = ddev->skb_check_crc(resp);
 704         if (rc) {
 705                 PROTOCOL_ERR("14.4.1.6");
 706                 goto exit;
 707         }
 708
 709         rc = digital_skb_pull_dep_sod(ddev, resp);
 710         if (rc) {
 711                 PROTOCOL_ERR("14.4.1.2");
 712                 goto exit;
 713         }
 714
 715         atr_req = (struct digital_atr_req *)resp->data;
 716
 717         if (atr_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
 718             atr_req->cmd != DIGITAL_CMD_ATR_REQ) {
 719                 rc = -EINVAL;
 720                 goto exit;
 721         }
 722
 723         rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
 724                                      NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED);
 725         if (rc)
 726                 goto exit;
 727
 728         rc = digital_tg_send_atr_res(ddev, atr_req);
 729         if (rc)
 730                 goto exit;
 731
 732         gb_len = resp->len - sizeof(struct digital_atr_req);
 733         rc = nfc_tm_activated(ddev->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
 734                               NFC_COMM_PASSIVE, atr_req->gb, gb_len);
 735         if (rc)
 736                 goto exit;
 737
 738         ddev->poll_tech_count = 0;
 739
 740         rc = 0;
 741 exit:
 742         if (rc)
 743                 digital_poll_next_tech(ddev);
 744
 745         dev_kfree_skb(resp);
 746 }