summaryrefslogtreecommitdiff
path: root/net/nfc/nci/core.c
blob: c55f233a5e2c76bda9184918f909d941afe9e98f (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
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
/*
 *  The NFC Controller Interface is the communication protocol between an
 *  NFC Controller (NFCC) and a Device Host (DH).
 *
 *  Copyright (C) 2011 Texas Instruments, Inc.
 *
 *  Written by Ilan Elias <ilane@ti.com>
 *
 *  Acknowledgements:
 *  This file is based on hci_core.c, which was written
 *  by Maxim Krasnyansky.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2
 *  as published by the Free Software Foundation
 *
 *  This program is distributed in the hope that 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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/export.h>
#include <linux/sched.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>

#include "../nfc.h"
#include <net/nfc/nci.h>
#include <net/nfc/nci_core.h>
#include <linux/nfc.h>

static void nci_cmd_work(struct work_struct *work);
static void nci_rx_work(struct work_struct *work);
static void nci_tx_work(struct work_struct *work);

/* ---- NCI requests ---- */

void nci_req_complete(struct nci_dev *ndev, int result)
{
	if (ndev->req_status == NCI_REQ_PEND) {
		ndev->req_result = result;
		ndev->req_status = NCI_REQ_DONE;
		complete(&ndev->req_completion);
	}
}

static void nci_req_cancel(struct nci_dev *ndev, int err)
{
	if (ndev->req_status == NCI_REQ_PEND) {
		ndev->req_result = err;
		ndev->req_status = NCI_REQ_CANCELED;
		complete(&ndev->req_completion);
	}
}

/* Execute request and wait for completion. */
static int __nci_request(struct nci_dev *ndev,
	void (*req)(struct nci_dev *ndev, unsigned long opt),
	unsigned long opt,
	__u32 timeout)
{
	int rc = 0;
	long completion_rc;

	ndev->req_status = NCI_REQ_PEND;

	init_completion(&ndev->req_completion);
	req(ndev, opt);
	completion_rc = wait_for_completion_interruptible_timeout(
							&ndev->req_completion,
							timeout);

	pr_debug("wait_for_completion return %ld\n", completion_rc);

	if (completion_rc > 0) {
		switch (ndev->req_status) {
		case NCI_REQ_DONE:
			rc = nci_to_errno(ndev->req_result);
			break;

		case NCI_REQ_CANCELED:
			rc = -ndev->req_result;
			break;

		default:
			rc = -ETIMEDOUT;
			break;
		}
	} else {
		pr_err("wait_for_completion_interruptible_timeout failed %ld\n",
		       completion_rc);

		rc = ((completion_rc == 0) ? (-ETIMEDOUT) : (completion_rc));
	}

	ndev->req_status = ndev->req_result = 0;

	return rc;
}

static inline int nci_request(struct nci_dev *ndev,
		void (*req)(struct nci_dev *ndev, unsigned long opt),
		unsigned long opt, __u32 timeout)
{
	int rc;

	if (!test_bit(NCI_UP, &ndev->flags))
		return -ENETDOWN;

	/* Serialize all requests */
	mutex_lock(&ndev->req_lock);
	rc = __nci_request(ndev, req, opt, timeout);
	mutex_unlock(&ndev->req_lock);

	return rc;
}

static void nci_reset_req(struct nci_dev *ndev, unsigned long opt)
{
	struct nci_core_reset_cmd cmd;

	cmd.reset_type = NCI_RESET_TYPE_RESET_CONFIG;
	nci_send_cmd(ndev, NCI_OP_CORE_RESET_CMD, 1, &cmd);
}

static void nci_init_req(struct nci_dev *ndev, unsigned long opt)
{
	nci_send_cmd(ndev, NCI_OP_CORE_INIT_CMD, 0, NULL);
}

static void nci_init_complete_req(struct nci_dev *ndev, unsigned long opt)
{
	struct nci_rf_disc_map_cmd cmd;
	struct disc_map_config *cfg = cmd.mapping_configs;
	__u8 *num = &cmd.num_mapping_configs;
	int i;

	/* set rf mapping configurations */
	*num = 0;

	/* by default mapping is set to NCI_RF_INTERFACE_FRAME */
	for (i = 0; i < ndev->num_supported_rf_interfaces; i++) {
		if (ndev->supported_rf_interfaces[i] ==
			NCI_RF_INTERFACE_ISO_DEP) {
			cfg[*num].rf_protocol = NCI_RF_PROTOCOL_ISO_DEP;
			cfg[*num].mode = NCI_DISC_MAP_MODE_BOTH;
			cfg[*num].rf_interface_type = NCI_RF_INTERFACE_ISO_DEP;
			(*num)++;
		} else if (ndev->supported_rf_interfaces[i] ==
			NCI_RF_INTERFACE_NFC_DEP) {
			cfg[*num].rf_protocol = NCI_RF_PROTOCOL_NFC_DEP;
			cfg[*num].mode = NCI_DISC_MAP_MODE_BOTH;
			cfg[*num].rf_interface_type = NCI_RF_INTERFACE_NFC_DEP;
			(*num)++;
		}

		if (*num == NCI_MAX_NUM_MAPPING_CONFIGS)
			break;
	}

	nci_send_cmd(ndev, NCI_OP_RF_DISCOVER_MAP_CMD,
		(1 + ((*num)*sizeof(struct disc_map_config))),
		&cmd);
}

static void nci_rf_discover_req(struct nci_dev *ndev, unsigned long opt)
{
	struct nci_rf_disc_cmd cmd;
	__u32 protocols = opt;

	cmd.num_disc_configs = 0;

	if ((cmd.num_disc_configs < NCI_MAX_NUM_RF_CONFIGS) &&
		(protocols & NFC_PROTO_JEWEL_MASK
		|| protocols & NFC_PROTO_MIFARE_MASK
		|| protocols & NFC_PROTO_ISO14443_MASK
		|| protocols & NFC_PROTO_NFC_DEP_MASK)) {
		cmd.disc_configs[cmd.num_disc_configs].type =
		NCI_DISCOVERY_TYPE_POLL_A_PASSIVE;
		cmd.disc_configs[cmd.num_disc_configs].frequency = 1;
		cmd.num_disc_configs++;
	}

	if ((cmd.num_disc_configs < NCI_MAX_NUM_RF_CONFIGS) &&
		(protocols & NFC_PROTO_ISO14443_MASK)) {
		cmd.disc_configs[cmd.num_disc_configs].type =
		NCI_DISCOVERY_TYPE_POLL_B_PASSIVE;
		cmd.disc_configs[cmd.num_disc_configs].frequency = 1;
		cmd.num_disc_configs++;
	}

	if ((cmd.num_disc_configs < NCI_MAX_NUM_RF_CONFIGS) &&
		(protocols & NFC_PROTO_FELICA_MASK
		|| protocols & NFC_PROTO_NFC_DEP_MASK)) {
		cmd.disc_configs[cmd.num_disc_configs].type =
		NCI_DISCOVERY_TYPE_POLL_F_PASSIVE;
		cmd.disc_configs[cmd.num_disc_configs].frequency = 1;
		cmd.num_disc_configs++;
	}

	nci_send_cmd(ndev, NCI_OP_RF_DISCOVER_CMD,
		(1 + (cmd.num_disc_configs*sizeof(struct disc_config))),
		&cmd);
}

static void nci_rf_deactivate_req(struct nci_dev *ndev, unsigned long opt)
{
	struct nci_rf_deactivate_cmd cmd;

	cmd.type = NCI_DEACTIVATE_TYPE_IDLE_MODE;

	nci_send_cmd(ndev, NCI_OP_RF_DEACTIVATE_CMD,
			sizeof(struct nci_rf_deactivate_cmd),
			&cmd);
}

static int nci_open_device(struct nci_dev *ndev)
{
	int rc = 0;

	mutex_lock(&ndev->req_lock);

	if (test_bit(NCI_UP, &ndev->flags)) {
		rc = -EALREADY;
		goto done;
	}

	if (ndev->ops->open(ndev)) {
		rc = -EIO;
		goto done;
	}

	atomic_set(&ndev->cmd_cnt, 1);

	set_bit(NCI_INIT, &ndev->flags);

	rc = __nci_request(ndev, nci_reset_req, 0,
				msecs_to_jiffies(NCI_RESET_TIMEOUT));

	if (!rc) {
		rc = __nci_request(ndev, nci_init_req, 0,
				msecs_to_jiffies(NCI_INIT_TIMEOUT));
	}

	if (!rc) {
		rc = __nci_request(ndev, nci_init_complete_req, 0,
				msecs_to_jiffies(NCI_INIT_TIMEOUT));
	}

	clear_bit(NCI_INIT, &ndev->flags);

	if (!rc) {
		set_bit(NCI_UP, &ndev->flags);
	} else {
		/* Init failed, cleanup */
		skb_queue_purge(&ndev->cmd_q);
		skb_queue_purge(&ndev->rx_q);
		skb_queue_purge(&ndev->tx_q);

		ndev->ops->close(ndev);
		ndev->flags = 0;
	}

done:
	mutex_unlock(&ndev->req_lock);
	return rc;
}

static int nci_close_device(struct nci_dev *ndev)
{
	nci_req_cancel(ndev, ENODEV);
	mutex_lock(&ndev->req_lock);

	if (!test_and_clear_bit(NCI_UP, &ndev->flags)) {
		del_timer_sync(&ndev->cmd_timer);
		mutex_unlock(&ndev->req_lock);
		return 0;
	}

	/* Drop RX and TX queues */
	skb_queue_purge(&ndev->rx_q);
	skb_queue_purge(&ndev->tx_q);

	/* Flush RX and TX wq */
	flush_workqueue(ndev->rx_wq);
	flush_workqueue(ndev->tx_wq);

	/* Reset device */
	skb_queue_purge(&ndev->cmd_q);
	atomic_set(&ndev->cmd_cnt, 1);

	set_bit(NCI_INIT, &ndev->flags);
	__nci_request(ndev, nci_reset_req, 0,
				msecs_to_jiffies(NCI_RESET_TIMEOUT));
	clear_bit(NCI_INIT, &ndev->flags);

	/* Flush cmd wq */
	flush_workqueue(ndev->cmd_wq);

	/* After this point our queues are empty
	 * and no works are scheduled. */
	ndev->ops->close(ndev);

	/* Clear flags */
	ndev->flags = 0;

	mutex_unlock(&ndev->req_lock);

	return 0;
}

/* NCI command timer function */
static void nci_cmd_timer(unsigned long arg)
{
	struct nci_dev *ndev = (void *) arg;

	atomic_set(&ndev->cmd_cnt, 1);
	queue_work(ndev->cmd_wq, &ndev->cmd_work);
}

static int nci_dev_up(struct nfc_dev *nfc_dev)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);

	return nci_open_device(ndev);
}

static int nci_dev_down(struct nfc_dev *nfc_dev)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);

	return nci_close_device(ndev);
}

static int nci_start_poll(struct nfc_dev *nfc_dev, __u32 protocols)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
	int rc;

	if (test_bit(NCI_DISCOVERY, &ndev->flags)) {
		pr_err("unable to start poll, since poll is already active\n");
		return -EBUSY;
	}

	if (ndev->target_active_prot) {
		pr_err("there is an active target\n");
		return -EBUSY;
	}

	if (test_bit(NCI_POLL_ACTIVE, &ndev->flags)) {
		pr_debug("target is active, implicitly deactivate...\n");

		rc = nci_request(ndev, nci_rf_deactivate_req, 0,
			msecs_to_jiffies(NCI_RF_DEACTIVATE_TIMEOUT));
		if (rc)
			return -EBUSY;
	}

	rc = nci_request(ndev, nci_rf_discover_req, protocols,
		msecs_to_jiffies(NCI_RF_DISC_TIMEOUT));

	if (!rc)
		ndev->poll_prots = protocols;

	return rc;
}

static void nci_stop_poll(struct nfc_dev *nfc_dev)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);

	if (!test_bit(NCI_DISCOVERY, &ndev->flags)) {
		pr_err("unable to stop poll, since poll is not active\n");
		return;
	}

	nci_request(ndev, nci_rf_deactivate_req, 0,
		msecs_to_jiffies(NCI_RF_DEACTIVATE_TIMEOUT));
}

static int nci_activate_target(struct nfc_dev *nfc_dev, __u32 target_idx,
				__u32 protocol)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);

	pr_debug("target_idx %d, protocol 0x%x\n", target_idx, protocol);

	if (!test_bit(NCI_POLL_ACTIVE, &ndev->flags)) {
		pr_err("there is no available target to activate\n");
		return -EINVAL;
	}

	if (ndev->target_active_prot) {
		pr_err("there is already an active target\n");
		return -EBUSY;
	}

	if (!(ndev->target_available_prots & (1 << protocol))) {
		pr_err("target does not support the requested protocol 0x%x\n",
		       protocol);
		return -EINVAL;
	}

	ndev->target_active_prot = protocol;
	ndev->target_available_prots = 0;

	return 0;
}

static void nci_deactivate_target(struct nfc_dev *nfc_dev, __u32 target_idx)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);

	pr_debug("target_idx %d\n", target_idx);

	if (!ndev->target_active_prot) {
		pr_err("unable to deactivate target, no active target\n");
		return;
	}

	ndev->target_active_prot = 0;

	if (test_bit(NCI_POLL_ACTIVE, &ndev->flags)) {
		nci_request(ndev, nci_rf_deactivate_req, 0,
			msecs_to_jiffies(NCI_RF_DEACTIVATE_TIMEOUT));
	}
}

static int nci_data_exchange(struct nfc_dev *nfc_dev, __u32 target_idx,
						struct sk_buff *skb,
						data_exchange_cb_t cb,
						void *cb_context)
{
	struct nci_dev *ndev = nfc_get_drvdata(nfc_dev);
	int rc;

	pr_debug("target_idx %d, len %d\n", target_idx, skb->len);

	if (!ndev->target_active_prot) {
		pr_err("unable to exchange data, no active target\n");
		return -EINVAL;
	}

	if (test_and_set_bit(NCI_DATA_EXCHANGE, &ndev->flags))
		return -EBUSY;

	/* store cb and context to be used on receiving data */
	ndev->data_exchange_cb = cb;
	ndev->data_exchange_cb_context = cb_context;

	rc = nci_send_data(ndev, NCI_STATIC_RF_CONN_ID, skb);
	if (rc)
		clear_bit(NCI_DATA_EXCHANGE, &ndev->flags);

	return rc;
}

static struct nfc_ops nci_nfc_ops = {
	.dev_up = nci_dev_up,
	.dev_down = nci_dev_down,
	.start_poll = nci_start_poll,
	.stop_poll = nci_stop_poll,
	.activate_target = nci_activate_target,
	.deactivate_target = nci_deactivate_target,
	.data_exchange = nci_data_exchange,
};

/* ---- Interface to NCI drivers ---- */

/**
 * nci_allocate_device - allocate a new nci device
 *
 * @ops: device operations
 * @supported_protocols: NFC protocols supported by the device
 */
struct nci_dev *nci_allocate_device(struct nci_ops *ops,
					__u32 supported_protocols,
					int tx_headroom,
					int tx_tailroom)
{
	struct nci_dev *ndev;

	pr_debug("supported_protocols 0x%x\n", supported_protocols);

	if (!ops->open || !ops->close || !ops->send)
		return NULL;

	if (!supported_protocols)
		return NULL;

	ndev = kzalloc(sizeof(struct nci_dev), GFP_KERNEL);
	if (!ndev)
		return NULL;

	ndev->ops = ops;
	ndev->tx_headroom = tx_headroom;
	ndev->tx_tailroom = tx_tailroom;

	ndev->nfc_dev = nfc_allocate_device(&nci_nfc_ops,
						supported_protocols,
						tx_headroom + NCI_DATA_HDR_SIZE,
						tx_tailroom);
	if (!ndev->nfc_dev)
		goto free_exit;

	nfc_set_drvdata(ndev->nfc_dev, ndev);

	return ndev;

free_exit:
	kfree(ndev);
	return NULL;
}
EXPORT_SYMBOL(nci_allocate_device);

/**
 * nci_free_device - deallocate nci device
 *
 * @ndev: The nci device to deallocate
 */
void nci_free_device(struct nci_dev *ndev)
{
	nfc_free_device(ndev->nfc_dev);
	kfree(ndev);
}
EXPORT_SYMBOL(nci_free_device);

/**
 * nci_register_device - register a nci device in the nfc subsystem
 *
 * @dev: The nci device to register
 */
int nci_register_device(struct nci_dev *ndev)
{
	int rc;
	struct device *dev = &ndev->nfc_dev->dev;
	char name[32];

	rc = nfc_register_device(ndev->nfc_dev);
	if (rc)
		goto exit;

	ndev->flags = 0;

	INIT_WORK(&ndev->cmd_work, nci_cmd_work);
	snprintf(name, sizeof(name), "%s_nci_cmd_wq", dev_name(dev));
	ndev->cmd_wq = create_singlethread_workqueue(name);
	if (!ndev->cmd_wq) {
		rc = -ENOMEM;
		goto unreg_exit;
	}

	INIT_WORK(&ndev->rx_work, nci_rx_work);
	snprintf(name, sizeof(name), "%s_nci_rx_wq", dev_name(dev));
	ndev->rx_wq = create_singlethread_workqueue(name);
	if (!ndev->rx_wq) {
		rc = -ENOMEM;
		goto destroy_cmd_wq_exit;
	}

	INIT_WORK(&ndev->tx_work, nci_tx_work);
	snprintf(name, sizeof(name), "%s_nci_tx_wq", dev_name(dev));
	ndev->tx_wq = create_singlethread_workqueue(name);
	if (!ndev->tx_wq) {
		rc = -ENOMEM;
		goto destroy_rx_wq_exit;
	}

	skb_queue_head_init(&ndev->cmd_q);
	skb_queue_head_init(&ndev->rx_q);
	skb_queue_head_init(&ndev->tx_q);

	setup_timer(&ndev->cmd_timer, nci_cmd_timer,
			(unsigned long) ndev);

	mutex_init(&ndev->req_lock);

	goto exit;

destroy_rx_wq_exit:
	destroy_workqueue(ndev->rx_wq);

destroy_cmd_wq_exit:
	destroy_workqueue(ndev->cmd_wq);

unreg_exit:
	nfc_unregister_device(ndev->nfc_dev);

exit:
	return rc;
}
EXPORT_SYMBOL(nci_register_device);

/**
 * nci_unregister_device - unregister a nci device in the nfc subsystem
 *
 * @dev: The nci device to unregister
 */
void nci_unregister_device(struct nci_dev *ndev)
{
	nci_close_device(ndev);

	destroy_workqueue(ndev->cmd_wq);
	destroy_workqueue(ndev->rx_wq);
	destroy_workqueue(ndev->tx_wq);

	nfc_unregister_device(ndev->nfc_dev);
}
EXPORT_SYMBOL(nci_unregister_device);

/**
 * nci_recv_frame - receive frame from NCI drivers
 *
 * @skb: The sk_buff to receive
 */
int nci_recv_frame(struct sk_buff *skb)
{
	struct nci_dev *ndev = (struct nci_dev *) skb->dev;

	pr_debug("len %d\n", skb->len);

	if (!ndev || (!test_bit(NCI_UP, &ndev->flags)
		&& !test_bit(NCI_INIT, &ndev->flags))) {
		kfree_skb(skb);
		return -ENXIO;
	}

	/* Queue frame for rx worker thread */
	skb_queue_tail(&ndev->rx_q, skb);
	queue_work(ndev->rx_wq, &ndev->rx_work);

	return 0;
}
EXPORT_SYMBOL(nci_recv_frame);

static int nci_send_frame(struct sk_buff *skb)
{
	struct nci_dev *ndev = (struct nci_dev *) skb->dev;

	pr_debug("len %d\n", skb->len);

	if (!ndev) {
		kfree_skb(skb);
		return -ENODEV;
	}

	/* Get rid of skb owner, prior to sending to the driver. */
	skb_orphan(skb);

	return ndev->ops->send(skb);
}

/* Send NCI command */
int nci_send_cmd(struct nci_dev *ndev, __u16 opcode, __u8 plen, void *payload)
{
	struct nci_ctrl_hdr *hdr;
	struct sk_buff *skb;

	pr_debug("opcode 0x%x, plen %d\n", opcode, plen);

	skb = nci_skb_alloc(ndev, (NCI_CTRL_HDR_SIZE + plen), GFP_KERNEL);
	if (!skb) {
		pr_err("no memory for command\n");
		return -ENOMEM;
	}

	hdr = (struct nci_ctrl_hdr *) skb_put(skb, NCI_CTRL_HDR_SIZE);
	hdr->gid = nci_opcode_gid(opcode);
	hdr->oid = nci_opcode_oid(opcode);
	hdr->plen = plen;

	nci_mt_set((__u8 *)hdr, NCI_MT_CMD_PKT);
	nci_pbf_set((__u8 *)hdr, NCI_PBF_LAST);

	if (plen)
		memcpy(skb_put(skb, plen), payload, plen);

	skb->dev = (void *) ndev;

	skb_queue_tail(&ndev->cmd_q, skb);
	queue_work(ndev->cmd_wq, &ndev->cmd_work);

	return 0;
}

/* ---- NCI TX Data worker thread ---- */

static void nci_tx_work(struct work_struct *work)
{
	struct nci_dev *ndev = container_of(work, struct nci_dev, tx_work);
	struct sk_buff *skb;

	pr_debug("credits_cnt %d\n", atomic_read(&ndev->credits_cnt));

	/* Send queued tx data */
	while (atomic_read(&ndev->credits_cnt)) {
		skb = skb_dequeue(&ndev->tx_q);
		if (!skb)
			return;

		/* Check if data flow control is used */
		if (atomic_read(&ndev->credits_cnt) !=
				NCI_DATA_FLOW_CONTROL_NOT_USED)
			atomic_dec(&ndev->credits_cnt);

		pr_debug("NCI TX: MT=data, PBF=%d, conn_id=%d, plen=%d\n",
			 nci_pbf(skb->data),
			 nci_conn_id(skb->data),
			 nci_plen(skb->data));

		nci_send_frame(skb);
	}
}

/* ----- NCI RX worker thread (data & control) ----- */

static void nci_rx_work(struct work_struct *work)
{
	struct nci_dev *ndev = container_of(work, struct nci_dev, rx_work);
	struct sk_buff *skb;

	while ((skb = skb_dequeue(&ndev->rx_q))) {
		/* Process frame */
		switch (nci_mt(skb->data)) {
		case NCI_MT_RSP_PKT:
			nci_rsp_packet(ndev, skb);
			break;

		case NCI_MT_NTF_PKT:
			nci_ntf_packet(ndev, skb);
			break;

		case NCI_MT_DATA_PKT:
			nci_rx_data_packet(ndev, skb);
			break;

		default:
			pr_err("unknown MT 0x%x\n", nci_mt(skb->data));
			kfree_skb(skb);
			break;
		}
	}
}

/* ----- NCI TX CMD worker thread ----- */

static void nci_cmd_work(struct work_struct *work)
{
	struct nci_dev *ndev = container_of(work, struct nci_dev, cmd_work);
	struct sk_buff *skb;

	pr_debug("cmd_cnt %d\n", atomic_read(&ndev->cmd_cnt));

	/* Send queued command */
	if (atomic_read(&ndev->cmd_cnt)) {
		skb = skb_dequeue(&ndev->cmd_q);
		if (!skb)
			return;

		atomic_dec(&ndev->cmd_cnt);

		pr_debug("NCI TX: MT=cmd, PBF=%d, GID=0x%x, OID=0x%x, plen=%d\n",
			 nci_pbf(skb->data),
			 nci_opcode_gid(nci_opcode(skb->data)),
			 nci_opcode_oid(nci_opcode(skb->data)),
			 nci_plen(skb->data));

		nci_send_frame(skb);

		mod_timer(&ndev->cmd_timer,
			jiffies + msecs_to_jiffies(NCI_CMD_TIMEOUT));
	}
}