summaryrefslogtreecommitdiffstats
path: root/net/nfc/digital_dep.c
blob: 171cb9949ab58560bc3d1c997d963e2928cf5aa5 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
/*
 * NFC Digital Protocol stack
 * Copyright (c) 2013, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */

#define pr_fmt(fmt) "digital: %s: " fmt, __func__

#include "digital.h"

#define DIGITAL_NFC_DEP_FRAME_DIR_OUT 0xD4
#define DIGITAL_NFC_DEP_FRAME_DIR_IN  0xD5

#define DIGITAL_NFC_DEP_NFCA_SOD_SB   0xF0

#define DIGITAL_CMD_ATR_REQ 0x00
#define DIGITAL_CMD_ATR_RES 0x01
#define DIGITAL_CMD_PSL_REQ 0x04
#define DIGITAL_CMD_PSL_RES 0x05
#define DIGITAL_CMD_DEP_REQ 0x06
#define DIGITAL_CMD_DEP_RES 0x07

#define DIGITAL_ATR_REQ_MIN_SIZE 16
#define DIGITAL_ATR_REQ_MAX_SIZE 64

#define DIGITAL_LR_BITS_PAYLOAD_SIZE_254B 0x30
#define DIGITAL_GB_BIT	0x02

#define DIGITAL_NFC_DEP_PFB_TYPE(pfb) ((pfb) & 0xE0)

#define DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT 0x10

#define DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb) \
				((pfb) & DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT)
#define DIGITAL_NFC_DEP_MI_BIT_SET(pfb)  ((pfb) & 0x10)
#define DIGITAL_NFC_DEP_NAD_BIT_SET(pfb) ((pfb) & 0x08)
#define DIGITAL_NFC_DEP_DID_BIT_SET(pfb) ((pfb) & 0x04)
#define DIGITAL_NFC_DEP_PFB_PNI(pfb)     ((pfb) & 0x03)

#define DIGITAL_NFC_DEP_PFB_I_PDU          0x00
#define DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU   0x40
#define DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU 0x80

struct digital_atr_req {
	u8 dir;
	u8 cmd;
	u8 nfcid3[10];
	u8 did;
	u8 bs;
	u8 br;
	u8 pp;
	u8 gb[0];
} __packed;

struct digital_atr_res {
	u8 dir;
	u8 cmd;
	u8 nfcid3[10];
	u8 did;
	u8 bs;
	u8 br;
	u8 to;
	u8 pp;
	u8 gb[0];
} __packed;

struct digital_psl_req {
	u8 dir;
	u8 cmd;
	u8 did;
	u8 brs;
	u8 fsl;
} __packed;

struct digital_psl_res {
	u8 dir;
	u8 cmd;
	u8 did;
} __packed;

struct digital_dep_req_res {
	u8 dir;
	u8 cmd;
	u8 pfb;
} __packed;

static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
				    struct sk_buff *resp);

static void digital_skb_push_dep_sod(struct nfc_digital_dev *ddev,
				     struct sk_buff *skb)
{
	skb_push(skb, sizeof(u8));

	skb->data[0] = skb->len;

	if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
		*skb_push(skb, sizeof(u8)) = DIGITAL_NFC_DEP_NFCA_SOD_SB;
}

static int digital_skb_pull_dep_sod(struct nfc_digital_dev *ddev,
				    struct sk_buff *skb)
{
	u8 size;

	if (skb->len < 2)
		return -EIO;

	if (ddev->curr_rf_tech == NFC_DIGITAL_RF_TECH_106A)
		skb_pull(skb, sizeof(u8));

	size = skb->data[0];
	if (size != skb->len)
		return -EIO;

	skb_pull(skb, sizeof(u8));

	return 0;
}

static void digital_in_recv_atr_res(struct nfc_digital_dev *ddev, void *arg,
				 struct sk_buff *resp)
{
	struct nfc_target *target = arg;
	struct digital_atr_res *atr_res;
	u8 gb_len;
	int rc;

	if (IS_ERR(resp)) {
		rc = PTR_ERR(resp);
		resp = NULL;
		goto exit;
	}

	rc = ddev->skb_check_crc(resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.6");
		goto exit;
	}

	rc = digital_skb_pull_dep_sod(ddev, resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.2");
		goto exit;
	}

	if (resp->len < sizeof(struct digital_atr_res)) {
		rc = -EIO;
		goto exit;
	}

	gb_len = resp->len - sizeof(struct digital_atr_res);

	atr_res = (struct digital_atr_res *)resp->data;

	rc = nfc_set_remote_general_bytes(ddev->nfc_dev, atr_res->gb, gb_len);
	if (rc)
		goto exit;

	rc = nfc_dep_link_is_up(ddev->nfc_dev, target->idx, NFC_COMM_ACTIVE,
				NFC_RF_INITIATOR);

	ddev->curr_nfc_dep_pni = 0;

exit:
	dev_kfree_skb(resp);

	if (rc)
		ddev->curr_protocol = 0;
}

int digital_in_send_atr_req(struct nfc_digital_dev *ddev,
			    struct nfc_target *target, __u8 comm_mode, __u8 *gb,
			    size_t gb_len)
{
	struct sk_buff *skb;
	struct digital_atr_req *atr_req;
	uint size;

	size = DIGITAL_ATR_REQ_MIN_SIZE + gb_len;

	if (size > DIGITAL_ATR_REQ_MAX_SIZE) {
		PROTOCOL_ERR("14.6.1.1");
		return -EINVAL;
	}

	skb = digital_skb_alloc(ddev, size);
	if (!skb)
		return -ENOMEM;

	skb_put(skb, sizeof(struct digital_atr_req));

	atr_req = (struct digital_atr_req *)skb->data;
	memset(atr_req, 0, sizeof(struct digital_atr_req));

	atr_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
	atr_req->cmd = DIGITAL_CMD_ATR_REQ;
	if (target->nfcid2_len)
		memcpy(atr_req->nfcid3, target->nfcid2, NFC_NFCID2_MAXSIZE);
	else
		get_random_bytes(atr_req->nfcid3, NFC_NFCID3_MAXSIZE);

	atr_req->did = 0;
	atr_req->bs = 0;
	atr_req->br = 0;

	atr_req->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;

	if (gb_len) {
		atr_req->pp |= DIGITAL_GB_BIT;
		memcpy(skb_put(skb, gb_len), gb, gb_len);
	}

	digital_skb_push_dep_sod(ddev, skb);

	ddev->skb_add_crc(skb);

	return digital_in_send_cmd(ddev, skb, 500, digital_in_recv_atr_res,
				   target);
}

static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
				struct digital_data_exch *data_exch, u8 rtox)
{
	struct digital_dep_req_res *dep_req;
	struct sk_buff *skb;
	int rc;

	skb = digital_skb_alloc(ddev, 1);
	if (!skb)
		return -ENOMEM;

	*skb_put(skb, 1) = rtox;

	skb_push(skb, sizeof(struct digital_dep_req_res));

	dep_req = (struct digital_dep_req_res *)skb->data;

	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
	dep_req->pfb = DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU |
		       DIGITAL_NFC_DEP_PFB_TIMEOUT_BIT;

	digital_skb_push_dep_sod(ddev, skb);

	ddev->skb_add_crc(skb);

	rc = digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
				 data_exch);

	return rc;
}

static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
				    struct sk_buff *resp)
{
	struct digital_data_exch *data_exch = arg;
	struct digital_dep_req_res *dep_res;
	u8 pfb;
	uint size;
	int rc;

	if (IS_ERR(resp)) {
		rc = PTR_ERR(resp);
		resp = NULL;
		goto exit;
	}

	rc = ddev->skb_check_crc(resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.6");
		goto error;
	}

	rc = digital_skb_pull_dep_sod(ddev, resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.2");
		goto exit;
	}

	dep_res = (struct digital_dep_req_res *)resp->data;

	if (resp->len < sizeof(struct digital_dep_req_res) ||
	    dep_res->dir != DIGITAL_NFC_DEP_FRAME_DIR_IN ||
	    dep_res->cmd != DIGITAL_CMD_DEP_RES) {
		rc = -EIO;
		goto error;
	}

	pfb = dep_res->pfb;

	switch (DIGITAL_NFC_DEP_PFB_TYPE(pfb)) {
	case DIGITAL_NFC_DEP_PFB_I_PDU:
		if (DIGITAL_NFC_DEP_PFB_PNI(pfb) != ddev->curr_nfc_dep_pni) {
			PROTOCOL_ERR("14.12.3.3");
			rc = -EIO;
			goto error;
		}

		ddev->curr_nfc_dep_pni =
			DIGITAL_NFC_DEP_PFB_PNI(ddev->curr_nfc_dep_pni + 1);
		rc = 0;
		break;

	case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
		pr_err("Received a ACK/NACK PDU\n");
		rc = -EIO;
		goto error;

	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
		if (!DIGITAL_NFC_DEP_PFB_IS_TIMEOUT(pfb)) {
			rc = -EINVAL;
			goto error;
		}

		rc = digital_in_send_rtox(ddev, data_exch, resp->data[3]);
		if (rc)
			goto error;

		kfree_skb(resp);
		return;
	}

	if (DIGITAL_NFC_DEP_MI_BIT_SET(pfb)) {
		pr_err("MI bit set. Chained PDU not supported\n");
		rc = -EIO;
		goto error;
	}

	size = sizeof(struct digital_dep_req_res);

	if (DIGITAL_NFC_DEP_DID_BIT_SET(pfb))
		size++;

	if (size > resp->len) {
		rc = -EIO;
		goto error;
	}

	skb_pull(resp, size);

exit:
	data_exch->cb(data_exch->cb_context, resp, rc);

error:
	kfree(data_exch);

	if (rc)
		kfree_skb(resp);
}

int digital_in_send_dep_req(struct nfc_digital_dev *ddev,
			    struct nfc_target *target, struct sk_buff *skb,
			    struct digital_data_exch *data_exch)
{
	struct digital_dep_req_res *dep_req;

	skb_push(skb, sizeof(struct digital_dep_req_res));

	dep_req = (struct digital_dep_req_res *)skb->data;
	dep_req->dir = DIGITAL_NFC_DEP_FRAME_DIR_OUT;
	dep_req->cmd = DIGITAL_CMD_DEP_REQ;
	dep_req->pfb = ddev->curr_nfc_dep_pni;

	digital_skb_push_dep_sod(ddev, skb);

	ddev->skb_add_crc(skb);

	return digital_in_send_cmd(ddev, skb, 1500, digital_in_recv_dep_res,
				   data_exch);
}

static void digital_tg_set_rf_tech(struct nfc_digital_dev *ddev, u8 rf_tech)
{
	ddev->curr_rf_tech = rf_tech;

	ddev->skb_add_crc = digital_skb_add_crc_none;
	ddev->skb_check_crc = digital_skb_check_crc_none;

	if (DIGITAL_DRV_CAPS_TG_CRC(ddev))
		return;

	switch (ddev->curr_rf_tech) {
	case NFC_DIGITAL_RF_TECH_106A:
		ddev->skb_add_crc = digital_skb_add_crc_a;
		ddev->skb_check_crc = digital_skb_check_crc_a;
		break;

	case NFC_DIGITAL_RF_TECH_212F:
	case NFC_DIGITAL_RF_TECH_424F:
		ddev->skb_add_crc = digital_skb_add_crc_f;
		ddev->skb_check_crc = digital_skb_check_crc_f;
		break;

	default:
		break;
	}
}

static void digital_tg_recv_dep_req(struct nfc_digital_dev *ddev, void *arg,
				    struct sk_buff *resp)
{
	int rc;
	struct digital_dep_req_res *dep_req;
	size_t size;

	if (IS_ERR(resp)) {
		rc = PTR_ERR(resp);
		resp = NULL;
		goto exit;
	}

	rc = ddev->skb_check_crc(resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.6");
		goto exit;
	}

	rc = digital_skb_pull_dep_sod(ddev, resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.2");
		goto exit;
	}

	size = sizeof(struct digital_dep_req_res);
	dep_req = (struct digital_dep_req_res *)resp->data;

	if (resp->len < size || dep_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
	    dep_req->cmd != DIGITAL_CMD_DEP_REQ) {
		rc = -EIO;
		goto exit;
	}

	if (DIGITAL_NFC_DEP_DID_BIT_SET(dep_req->pfb))
		size++;

	if (resp->len < size) {
		rc = -EIO;
		goto exit;
	}

	switch (DIGITAL_NFC_DEP_PFB_TYPE(dep_req->pfb)) {
	case DIGITAL_NFC_DEP_PFB_I_PDU:
		pr_debug("DIGITAL_NFC_DEP_PFB_I_PDU\n");
		ddev->curr_nfc_dep_pni = DIGITAL_NFC_DEP_PFB_PNI(dep_req->pfb);
		break;
	case DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU:
		pr_err("Received a ACK/NACK PDU\n");
		rc = -EINVAL;
		goto exit;
		break;
	case DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU:
		pr_err("Received a SUPERVISOR PDU\n");
		rc = -EINVAL;
		goto exit;
		break;
	}

	skb_pull(resp, size);

	rc = nfc_tm_data_received(ddev->nfc_dev, resp);

exit:
	if (rc)
		kfree_skb(resp);
}

int digital_tg_send_dep_res(struct nfc_digital_dev *ddev, struct sk_buff *skb)
{
	struct digital_dep_req_res *dep_res;

	skb_push(skb, sizeof(struct digital_dep_req_res));
	dep_res = (struct digital_dep_req_res *)skb->data;

	dep_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
	dep_res->cmd = DIGITAL_CMD_DEP_RES;
	dep_res->pfb = ddev->curr_nfc_dep_pni;

	digital_skb_push_dep_sod(ddev, skb);

	ddev->skb_add_crc(skb);

	return digital_tg_send_cmd(ddev, skb, 1500, digital_tg_recv_dep_req,
				   NULL);
}

static void digital_tg_send_psl_res_complete(struct nfc_digital_dev *ddev,
					     void *arg, struct sk_buff *resp)
{
	u8 rf_tech = (unsigned long)arg;

	if (IS_ERR(resp))
		return;

	digital_tg_set_rf_tech(ddev, rf_tech);

	digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_RF_TECH, rf_tech);

	digital_tg_listen(ddev, 1500, digital_tg_recv_dep_req, NULL);

	dev_kfree_skb(resp);
}

static int digital_tg_send_psl_res(struct nfc_digital_dev *ddev, u8 did,
				   u8 rf_tech)
{
	struct digital_psl_res *psl_res;
	struct sk_buff *skb;
	int rc;

	skb = digital_skb_alloc(ddev, sizeof(struct digital_psl_res));
	if (!skb)
		return -ENOMEM;

	skb_put(skb, sizeof(struct digital_psl_res));

	psl_res = (struct digital_psl_res *)skb->data;

	psl_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
	psl_res->cmd = DIGITAL_CMD_PSL_RES;
	psl_res->did = did;

	digital_skb_push_dep_sod(ddev, skb);

	ddev->skb_add_crc(skb);

	rc = digital_tg_send_cmd(ddev, skb, 0, digital_tg_send_psl_res_complete,
				 (void *)(unsigned long)rf_tech);

	if (rc)
		kfree_skb(skb);

	return rc;
}

static void digital_tg_recv_psl_req(struct nfc_digital_dev *ddev, void *arg,
				    struct sk_buff *resp)
{
	int rc;
	struct digital_psl_req *psl_req;
	u8 rf_tech;
	u8 dsi;

	if (IS_ERR(resp)) {
		rc = PTR_ERR(resp);
		resp = NULL;
		goto exit;
	}

	rc = ddev->skb_check_crc(resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.6");
		goto exit;
	}

	rc = digital_skb_pull_dep_sod(ddev, resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.2");
		goto exit;
	}

	psl_req = (struct digital_psl_req *)resp->data;

	if (resp->len != sizeof(struct digital_psl_req) ||
	    psl_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
	    psl_req->cmd != DIGITAL_CMD_PSL_REQ) {
		rc = -EIO;
		goto exit;
	}

	dsi = (psl_req->brs >> 3) & 0x07;
	switch (dsi) {
	case 0:
		rf_tech = NFC_DIGITAL_RF_TECH_106A;
		break;
	case 1:
		rf_tech = NFC_DIGITAL_RF_TECH_212F;
		break;
	case 2:
		rf_tech = NFC_DIGITAL_RF_TECH_424F;
		break;
	default:
		pr_err("Unsupported dsi value %d\n", dsi);
		goto exit;
	}

	rc = digital_tg_send_psl_res(ddev, psl_req->did, rf_tech);

exit:
	kfree_skb(resp);
}

static void digital_tg_send_atr_res_complete(struct nfc_digital_dev *ddev,
					     void *arg, struct sk_buff *resp)
{
	int offset;

	if (IS_ERR(resp)) {
		digital_poll_next_tech(ddev);
		return;
	}

	offset = 2;
	if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB)
		offset++;

	if (resp->data[offset] == DIGITAL_CMD_PSL_REQ)
		digital_tg_recv_psl_req(ddev, arg, resp);
	else
		digital_tg_recv_dep_req(ddev, arg, resp);
}

static int digital_tg_send_atr_res(struct nfc_digital_dev *ddev,
				   struct digital_atr_req *atr_req)
{
	struct digital_atr_res *atr_res;
	struct sk_buff *skb;
	u8 *gb;
	size_t gb_len;
	int rc;

	gb = nfc_get_local_general_bytes(ddev->nfc_dev, &gb_len);
	if (!gb)
		gb_len = 0;

	skb = digital_skb_alloc(ddev, sizeof(struct digital_atr_res) + gb_len);
	if (!skb)
		return -ENOMEM;

	skb_put(skb, sizeof(struct digital_atr_res));
	atr_res = (struct digital_atr_res *)skb->data;

	memset(atr_res, 0, sizeof(struct digital_atr_res));

	atr_res->dir = DIGITAL_NFC_DEP_FRAME_DIR_IN;
	atr_res->cmd = DIGITAL_CMD_ATR_RES;
	memcpy(atr_res->nfcid3, atr_req->nfcid3, sizeof(atr_req->nfcid3));
	atr_res->to = 8;
	atr_res->pp = DIGITAL_LR_BITS_PAYLOAD_SIZE_254B;
	if (gb_len) {
		skb_put(skb, gb_len);

		atr_res->pp |= DIGITAL_GB_BIT;
		memcpy(atr_res->gb, gb, gb_len);
	}

	digital_skb_push_dep_sod(ddev, skb);

	ddev->skb_add_crc(skb);

	rc = digital_tg_send_cmd(ddev, skb, 999,
				 digital_tg_send_atr_res_complete, NULL);
	if (rc) {
		kfree_skb(skb);
		return rc;
	}

	return rc;
}

void digital_tg_recv_atr_req(struct nfc_digital_dev *ddev, void *arg,
			     struct sk_buff *resp)
{
	int rc;
	struct digital_atr_req *atr_req;
	size_t gb_len, min_size;

	if (IS_ERR(resp)) {
		rc = PTR_ERR(resp);
		resp = NULL;
		goto exit;
	}

	if (!resp->len) {
		rc = -EIO;
		goto exit;
	}

	if (resp->data[0] == DIGITAL_NFC_DEP_NFCA_SOD_SB) {
		min_size = DIGITAL_ATR_REQ_MIN_SIZE + 2;
		digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_106A);
	} else {
		min_size = DIGITAL_ATR_REQ_MIN_SIZE + 1;
		digital_tg_set_rf_tech(ddev, NFC_DIGITAL_RF_TECH_212F);
	}

	if (resp->len < min_size) {
		rc = -EIO;
		goto exit;
	}

	ddev->curr_protocol = NFC_PROTO_NFC_DEP_MASK;

	rc = ddev->skb_check_crc(resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.6");
		goto exit;
	}

	rc = digital_skb_pull_dep_sod(ddev, resp);
	if (rc) {
		PROTOCOL_ERR("14.4.1.2");
		goto exit;
	}

	atr_req = (struct digital_atr_req *)resp->data;

	if (atr_req->dir != DIGITAL_NFC_DEP_FRAME_DIR_OUT ||
	    atr_req->cmd != DIGITAL_CMD_ATR_REQ) {
		rc = -EINVAL;
		goto exit;
	}

	rc = digital_tg_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING,
				     NFC_DIGITAL_FRAMING_NFC_DEP_ACTIVATED);
	if (rc)
		goto exit;

	rc = digital_tg_send_atr_res(ddev, atr_req);
	if (rc)
		goto exit;

	gb_len = resp->len - sizeof(struct digital_atr_req);
	rc = nfc_tm_activated(ddev->nfc_dev, NFC_PROTO_NFC_DEP_MASK,
			      NFC_COMM_PASSIVE, atr_req->gb, gb_len);
	if (rc)
		goto exit;

	ddev->poll_tech_count = 0;

	rc = 0;
exit:
	if (rc)
		digital_poll_next_tech(ddev);

	dev_kfree_skb(resp);
}