summaryrefslogtreecommitdiffstats
path: root/drivers/bluetooth/hci_bcsp.c
blob: 858fddb046de8caba0dc1b5c84051dff4d086270 (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
/* 
   BlueCore Serial Protocol (BCSP) for Linux Bluetooth stack (BlueZ).
   Copyright 2002 by Fabrizio Gennari <fabrizio.gennari@philips.com>

   Based on
       hci_h4.c  by Maxim Krasnyansky <maxk@qualcomm.com>
       ABCSP     by Carl Orsborn <cjo@csr.com>

   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;

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF THIRD PARTY RIGHTS.
   IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) AND AUTHOR(S) BE LIABLE FOR ANY
   CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES 
   WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 
   ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 
   OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

   ALL LIABILITY, INCLUDING LIABILITY FOR INFRINGEMENT OF ANY PATENTS, 
   COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS, RELATING TO USE OF THIS 
   SOFTWARE IS DISCLAIMED.
*/

/*
 * $Id: hci_bcsp.c,v 1.2 2002/09/26 05:05:14 maxk Exp $
 */

#define VERSION "0.2"

#include <linux/config.h>
#include <linux/module.h>

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/poll.h>

#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/signal.h>
#include <linux/ioctl.h>
#include <linux/skbuff.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include "hci_uart.h"
#include "hci_bcsp.h"

#ifndef CONFIG_BT_HCIUART_DEBUG
#undef  BT_DBG
#define BT_DBG( A... )
#endif

static int hciextn = 1;

/* ---- BCSP CRC calculation ---- */

/* Table for calculating CRC for polynomial 0x1021, LSB processed first,
initial value 0xffff, bits shifted in reverse order. */

static const u16 crc_table[] = {
	0x0000, 0x1081, 0x2102, 0x3183,
	0x4204, 0x5285, 0x6306, 0x7387,
	0x8408, 0x9489, 0xa50a, 0xb58b,
	0xc60c, 0xd68d, 0xe70e, 0xf78f
};

/* Initialise the crc calculator */
#define BCSP_CRC_INIT(x) x = 0xffff

/*
   Update crc with next data byte

   Implementation note
        The data byte is treated as two nibbles.  The crc is generated
        in reverse, i.e., bits are fed into the register from the top.
*/
static void bcsp_crc_update(u16 *crc, u8 d)
{
	u16 reg = *crc;

	reg = (reg >> 4) ^ crc_table[(reg ^ d) & 0x000f];
	reg = (reg >> 4) ^ crc_table[(reg ^ (d >> 4)) & 0x000f];

	*crc = reg;
}

/*
   Get reverse of generated crc

   Implementation note
        The crc generator (bcsp_crc_init() and bcsp_crc_update())
        creates a reversed crc, so it needs to be swapped back before
        being passed on.
*/
static u16 bcsp_crc_reverse(u16 crc)
{
	u16 b, rev;

	for (b = 0, rev = 0; b < 16; b++) {
		rev = rev << 1;
		rev |= (crc & 1);
		crc = crc >> 1;
	}
	return (rev);
}

/* ---- BCSP core ---- */

static void bcsp_slip_msgdelim(struct sk_buff *skb)
{
	const char pkt_delim = 0xc0;
	memcpy(skb_put(skb, 1), &pkt_delim, 1);
}

static void bcsp_slip_one_byte(struct sk_buff *skb, u8 c)
{
	const char esc_c0[2] = { 0xdb, 0xdc };
	const char esc_db[2] = { 0xdb, 0xdd };

	switch (c) {
	case 0xc0:
		memcpy(skb_put(skb, 2), &esc_c0, 2);
		break;
	case 0xdb:
		memcpy(skb_put(skb, 2), &esc_db, 2);
		break;
	default:
		memcpy(skb_put(skb, 1), &c, 1);
	}
}

static int bcsp_enqueue(struct hci_uart *hu, struct sk_buff *skb)
{
	struct bcsp_struct *bcsp = hu->priv;

	if (skb->len > 0xFFF) {
		BT_ERR("Packet too long");
		kfree_skb(skb);
		return 0;
	}

	switch (skb->pkt_type) {
	case HCI_ACLDATA_PKT:
	case HCI_COMMAND_PKT:
		skb_queue_tail(&bcsp->rel, skb);
		break;

	case HCI_SCODATA_PKT:
		skb_queue_tail(&bcsp->unrel, skb);
		break;

	default:
		BT_ERR("Unknown packet type");
		kfree_skb(skb);
		break;
	}

	return 0;
}

static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
		int len, int pkt_type)
{
	struct sk_buff *nskb;
	u8 hdr[4], chan;
	int rel, i;

#ifdef CONFIG_BT_HCIUART_BCSP_TXCRC
	u16 BCSP_CRC_INIT(bcsp_txmsg_crc);
#endif

	switch (pkt_type) {
	case HCI_ACLDATA_PKT:
		chan = 6;	/* BCSP ACL channel */
		rel = 1;	/* reliable channel */
		break;
	case HCI_COMMAND_PKT:
		chan = 5;	/* BCSP cmd/evt channel */
		rel = 1;	/* reliable channel */
		break;
	case HCI_SCODATA_PKT:
		chan = 7;	/* BCSP SCO channel */
		rel = 0;	/* unreliable channel */
		break;
	case BCSP_LE_PKT:
		chan = 1;	/* BCSP LE channel */
		rel = 0;	/* unreliable channel */
		break;
	case BCSP_ACK_PKT:
		chan = 0;	/* BCSP internal channel */
		rel = 0;	/* unreliable channel */
		break;
	default:
		BT_ERR("Unknown packet type");
		return NULL;
	}

	if (hciextn && chan == 5) {
		struct hci_command_hdr *hdr = (struct hci_command_hdr *) data;

		if (hci_opcode_ogf(__le16_to_cpu(hdr->opcode)) == OGF_VENDOR_CMD) {
			u8 desc = *(data + HCI_COMMAND_HDR_SIZE);
			if ((desc & 0xf0) == 0xc0) {
				data += HCI_COMMAND_HDR_SIZE + 1;
				len  -= HCI_COMMAND_HDR_SIZE + 1;
				chan = desc & 0x0f;
			}
		}
	}

	/* Max len of packet: (original len +4(bcsp hdr) +2(crc))*2
	   (because bytes 0xc0 and 0xdb are escaped, worst case is
	   when the packet is all made of 0xc0 and 0xdb :) )
	   + 2 (0xc0 delimiters at start and end). */

	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
	if (!nskb)
		return NULL;

	nskb->pkt_type = pkt_type;

	bcsp_slip_msgdelim(nskb);

	hdr[0] = bcsp->rxseq_txack << 3;
	bcsp->txack_req = 0;
	BT_DBG("We request packet no %u to card", bcsp->rxseq_txack);

	if (rel) {
		hdr[0] |= 0x80 + bcsp->msgq_txseq;
		BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq);
		bcsp->msgq_txseq = ++(bcsp->msgq_txseq) & 0x07;
	}
#ifdef CONFIG_BT_HCIUART_BCSP_TXCRC
	hdr[0] |= 0x40;
#endif

	hdr[1] = ((len << 4) & 0xff) | chan;
	hdr[2] = len >> 4;
	hdr[3] = ~(hdr[0] + hdr[1] + hdr[2]);

	/* Put BCSP header */
	for (i = 0; i < 4; i++) {
		bcsp_slip_one_byte(nskb, hdr[i]);
#ifdef CONFIG_BT_HCIUART_BCSP_TXCRC
		bcsp_crc_update(&bcsp_txmsg_crc, hdr[i]);
#endif
	}

	/* Put payload */
	for (i = 0; i < len; i++) {
		bcsp_slip_one_byte(nskb, data[i]);
#ifdef CONFIG_BT_HCIUART_BCSP_TXCRC
		bcsp_crc_update(&bcsp_txmsg_crc, data[i]);
#endif
	}

#ifdef CONFIG_BT_HCIUART_BCSP_TXCRC
	/* Put CRC */
	bcsp_txmsg_crc = bcsp_crc_reverse(bcsp_txmsg_crc);
	bcsp_slip_one_byte(nskb, (u8) ((bcsp_txmsg_crc >> 8) & 0x00ff));
	bcsp_slip_one_byte(nskb, (u8) (bcsp_txmsg_crc & 0x00ff));
#endif

	bcsp_slip_msgdelim(nskb);
	return nskb;
}

/* This is a rewrite of pkt_avail in ABCSP */
static struct sk_buff *bcsp_dequeue(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	unsigned long flags;
	struct sk_buff *skb;
	
	/* First of all, check for unreliable messages in the queue,
	   since they have priority */

	if ((skb = skb_dequeue(&bcsp->unrel)) != NULL) {
		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len, skb->pkt_type);
		if (nskb) {
			kfree_skb(skb);
			return nskb;
		} else {
			skb_queue_head(&bcsp->unrel, skb);
			BT_ERR("Could not dequeue pkt because alloc_skb failed");
		}
	}

	/* Now, try to send a reliable pkt. We can only send a
	   reliable packet if the number of packets sent but not yet ack'ed
	   is < than the winsize */

	spin_lock_irqsave(&bcsp->unack.lock, flags);

	if (bcsp->unack.qlen < BCSP_TXWINSIZE && (skb = skb_dequeue(&bcsp->rel)) != NULL) {
		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len, skb->pkt_type);
		if (nskb) {
			__skb_queue_tail(&bcsp->unack, skb);
			mod_timer(&bcsp->tbcsp, jiffies + HZ / 4);
			spin_unlock_irqrestore(&bcsp->unack.lock, flags);
			return nskb;
		} else {
			skb_queue_head(&bcsp->rel, skb);
			BT_ERR("Could not dequeue pkt because alloc_skb failed");
		}
	}

	spin_unlock_irqrestore(&bcsp->unack.lock, flags);


	/* We could not send a reliable packet, either because there are
	   none or because there are too many unack'ed pkts. Did we receive
	   any packets we have not acknowledged yet ? */

	if (bcsp->txack_req) {
		/* if so, craft an empty ACK pkt and send it on BCSP unreliable
		   channel 0 */
		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, NULL, 0, BCSP_ACK_PKT);
		return nskb;
	}

	/* We have nothing to send */
	return NULL;
}

static int bcsp_flush(struct hci_uart *hu)
{
	BT_DBG("hu %p", hu);
	return 0;
}

/* Remove ack'ed packets */
static void bcsp_pkt_cull(struct bcsp_struct *bcsp)
{
	unsigned long flags;
	struct sk_buff *skb;
	int i, pkts_to_be_removed;
	u8 seqno;

	spin_lock_irqsave(&bcsp->unack.lock, flags);

	pkts_to_be_removed = bcsp->unack.qlen;
	seqno = bcsp->msgq_txseq;

	while (pkts_to_be_removed) {
		if (bcsp->rxack == seqno)
			break;
		pkts_to_be_removed--;
		seqno = (seqno - 1) & 0x07;
	}

	if (bcsp->rxack != seqno)
		BT_ERR("Peer acked invalid packet");

	BT_DBG("Removing %u pkts out of %u, up to seqno %u",
	       pkts_to_be_removed, bcsp->unack.qlen, (seqno - 1) & 0x07);

	for (i = 0, skb = ((struct sk_buff *) &bcsp->unack)->next; i < pkts_to_be_removed
			&& skb != (struct sk_buff *) &bcsp->unack; i++) {
		struct sk_buff *nskb;

		nskb = skb->next;
		__skb_unlink(skb, &bcsp->unack);
		kfree_skb(skb);
		skb = nskb;
	}
	if (bcsp->unack.qlen == 0)
		del_timer(&bcsp->tbcsp);
	spin_unlock_irqrestore(&bcsp->unack.lock, flags);

	if (i != pkts_to_be_removed)
		BT_ERR("Removed only %u out of %u pkts", i, pkts_to_be_removed);
}

/* Handle BCSP link-establishment packets. When we
   detect a "sync" packet, symptom that the BT module has reset,
   we do nothing :) (yet) */
static void bcsp_handle_le_pkt(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	u8 conf_pkt[4]     = { 0xad, 0xef, 0xac, 0xed };
	u8 conf_rsp_pkt[4] = { 0xde, 0xad, 0xd0, 0xd0 };
	u8 sync_pkt[4]     = { 0xda, 0xdc, 0xed, 0xed };

	/* spot "conf" pkts and reply with a "conf rsp" pkt */
	if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
			!memcmp(&bcsp->rx_skb->data[4], conf_pkt, 4)) {
		struct sk_buff *nskb = alloc_skb(4, GFP_ATOMIC);

		BT_DBG("Found a LE conf pkt");
		if (!nskb)
			return;
		memcpy(skb_put(nskb, 4), conf_rsp_pkt, 4);
		nskb->pkt_type = BCSP_LE_PKT;

		skb_queue_head(&bcsp->unrel, nskb);
		hci_uart_tx_wakeup(hu);
	}
	/* Spot "sync" pkts. If we find one...disaster! */
	else if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
			!memcmp(&bcsp->rx_skb->data[4], sync_pkt, 4)) {
		BT_ERR("Found a LE sync pkt, card has reset");
	}
}

static inline void bcsp_unslip_one_byte(struct bcsp_struct *bcsp, unsigned char byte)
{
	const u8 c0 = 0xc0, db = 0xdb;

	switch (bcsp->rx_esc_state) {
	case BCSP_ESCSTATE_NOESC:
		switch (byte) {
		case 0xdb:
			bcsp->rx_esc_state = BCSP_ESCSTATE_ESC;
			break;
		default:
			memcpy(skb_put(bcsp->rx_skb, 1), &byte, 1);
			if ((bcsp->rx_skb-> data[0] & 0x40) != 0 && 
					bcsp->rx_state != BCSP_W4_CRC)
				bcsp_crc_update(&bcsp->message_crc, byte);
			bcsp->rx_count--;
		}
		break;

	case BCSP_ESCSTATE_ESC:
		switch (byte) {
		case 0xdc:
			memcpy(skb_put(bcsp->rx_skb, 1), &c0, 1);
			if ((bcsp->rx_skb-> data[0] & 0x40) != 0 && 
					bcsp->rx_state != BCSP_W4_CRC)
				bcsp_crc_update(&bcsp-> message_crc, 0xc0);
			bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
			bcsp->rx_count--;
			break;

		case 0xdd:
			memcpy(skb_put(bcsp->rx_skb, 1), &db, 1);
			if ((bcsp->rx_skb-> data[0] & 0x40) != 0 && 
					bcsp->rx_state != BCSP_W4_CRC) 
				bcsp_crc_update(&bcsp-> message_crc, 0xdb);
			bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
			bcsp->rx_count--;
			break;

		default:
			BT_ERR ("Invalid byte %02x after esc byte", byte);
			kfree_skb(bcsp->rx_skb);
			bcsp->rx_skb = NULL;
			bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
			bcsp->rx_count = 0;
		}
	}
}

static inline void bcsp_complete_rx_pkt(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	int pass_up;

	if (bcsp->rx_skb->data[0] & 0x80) {	/* reliable pkt */
		BT_DBG("Received seqno %u from card", bcsp->rxseq_txack);
		bcsp->rxseq_txack++;
		bcsp->rxseq_txack %= 0x8;
		bcsp->txack_req    = 1;

		/* If needed, transmit an ack pkt */
		hci_uart_tx_wakeup(hu);
	}

	bcsp->rxack = (bcsp->rx_skb->data[0] >> 3) & 0x07;
	BT_DBG("Request for pkt %u from card", bcsp->rxack);

	bcsp_pkt_cull(bcsp);
	if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
			bcsp->rx_skb->data[0] & 0x80) {
		bcsp->rx_skb->pkt_type = HCI_ACLDATA_PKT;
		pass_up = 1;
	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
			bcsp->rx_skb->data[0] & 0x80) {
		bcsp->rx_skb->pkt_type = HCI_EVENT_PKT;
		pass_up = 1;
	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
		bcsp->rx_skb->pkt_type = HCI_SCODATA_PKT;
		pass_up = 1;
	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
			!(bcsp->rx_skb->data[0] & 0x80)) {
		bcsp_handle_le_pkt(hu);
		pass_up = 0;
	} else
		pass_up = 0;

	if (!pass_up) {
		struct hci_event_hdr hdr;
		u8 desc = (bcsp->rx_skb->data[1] & 0x0f);

		if (desc != 0 && desc != 1) {
			if (hciextn) {
				desc |= 0xc0;
				skb_pull(bcsp->rx_skb, 4);
				memcpy(skb_push(bcsp->rx_skb, 1), &desc, 1);

				hdr.evt = 0xff;
				hdr.plen = bcsp->rx_skb->len;
				memcpy(skb_push(bcsp->rx_skb, HCI_EVENT_HDR_SIZE), &hdr, HCI_EVENT_HDR_SIZE);
				bcsp->rx_skb->pkt_type = HCI_EVENT_PKT;

				hci_recv_frame(bcsp->rx_skb);
			} else {
				BT_ERR ("Packet for unknown channel (%u %s)",
					bcsp->rx_skb->data[1] & 0x0f,
					bcsp->rx_skb->data[0] & 0x80 ? 
					"reliable" : "unreliable");
				kfree_skb(bcsp->rx_skb);
			}
		} else
			kfree_skb(bcsp->rx_skb);
	} else {
		/* Pull out BCSP hdr */
		skb_pull(bcsp->rx_skb, 4);

		hci_recv_frame(bcsp->rx_skb);
	}
	bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
	bcsp->rx_skb = NULL;
}

/* Recv data */
static int bcsp_recv(struct hci_uart *hu, void *data, int count)
{
	struct bcsp_struct *bcsp = hu->priv;
	register unsigned char *ptr;

	BT_DBG("hu %p count %d rx_state %d rx_count %ld", 
		hu, count, bcsp->rx_state, bcsp->rx_count);

	ptr = data;
	while (count) {
		if (bcsp->rx_count) {
			if (*ptr == 0xc0) {
				BT_ERR("Short BCSP packet");
				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_START;
				bcsp->rx_count = 0;
			} else
				bcsp_unslip_one_byte(bcsp, *ptr);

			ptr++; count--;
			continue;
		}

		switch (bcsp->rx_state) {
		case BCSP_W4_BCSP_HDR:
			if ((0xff & (u8) ~ (bcsp->rx_skb->data[0] + bcsp->rx_skb->data[1] +
					bcsp->rx_skb->data[2])) != bcsp->rx_skb->data[3]) {
				BT_ERR("Error in BCSP hdr checksum");
				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
				bcsp->rx_count = 0;
				continue;
			}
			if (bcsp->rx_skb->data[0] & 0x80	/* reliable pkt */
			    		&& (bcsp->rx_skb->data[0] & 0x07) != bcsp->rxseq_txack) {
				BT_ERR ("Out-of-order packet arrived, got %u expected %u",
					bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);

				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
				bcsp->rx_count = 0;
				continue;
			}
			bcsp->rx_state = BCSP_W4_DATA;
			bcsp->rx_count = (bcsp->rx_skb->data[1] >> 4) + 
					(bcsp->rx_skb->data[2] << 4);	/* May be 0 */
			continue;

		case BCSP_W4_DATA:
			if (bcsp->rx_skb->data[0] & 0x40) {	/* pkt with crc */
				bcsp->rx_state = BCSP_W4_CRC;
				bcsp->rx_count = 2;
			} else
				bcsp_complete_rx_pkt(hu);
			continue;

		case BCSP_W4_CRC:
			if (bcsp_crc_reverse(bcsp->message_crc) !=
					(bcsp->rx_skb->data[bcsp->rx_skb->len - 2] << 8) +
					bcsp->rx_skb->data[bcsp->rx_skb->len - 1]) {

				BT_ERR ("Checksum failed: computed %04x received %04x",
					bcsp_crc_reverse(bcsp->message_crc),
				     	(bcsp->rx_skb-> data[bcsp->rx_skb->len - 2] << 8) +
				     	bcsp->rx_skb->data[bcsp->rx_skb->len - 1]);

				kfree_skb(bcsp->rx_skb);
				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
				bcsp->rx_count = 0;
				continue;
			}
			skb_trim(bcsp->rx_skb, bcsp->rx_skb->len - 2);
			bcsp_complete_rx_pkt(hu);
			continue;

		case BCSP_W4_PKT_DELIMITER:
			switch (*ptr) {
			case 0xc0:
				bcsp->rx_state = BCSP_W4_PKT_START;
				break;
			default:
				/*BT_ERR("Ignoring byte %02x", *ptr);*/
				break;
			}
			ptr++; count--;
			break;

		case BCSP_W4_PKT_START:
			switch (*ptr) {
			case 0xc0:
				ptr++; count--;
				break;

			default:
				bcsp->rx_state = BCSP_W4_BCSP_HDR;
				bcsp->rx_count = 4;
				bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
				BCSP_CRC_INIT(bcsp->message_crc);
				
				/* Do not increment ptr or decrement count
				 * Allocate packet. Max len of a BCSP pkt= 
				 * 0xFFF (payload) +4 (header) +2 (crc) */

				bcsp->rx_skb = bt_skb_alloc(0x1005, GFP_ATOMIC);
				if (!bcsp->rx_skb) {
					BT_ERR("Can't allocate mem for new packet");
					bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
					bcsp->rx_count = 0;
					return 0;
				}
				bcsp->rx_skb->dev = (void *) hu->hdev;
				break;
			}
			break;
		}
	}
	return count;
}

	/* Arrange to retransmit all messages in the relq. */
static void bcsp_timed_event(unsigned long arg)
{
	struct hci_uart *hu = (struct hci_uart *) arg;
	struct bcsp_struct *bcsp = hu->priv;
	struct sk_buff *skb;
	unsigned long flags;

	BT_DBG("hu %p retransmitting %u pkts", hu, bcsp->unack.qlen);

	spin_lock_irqsave(&bcsp->unack.lock, flags);

	while ((skb = __skb_dequeue_tail(&bcsp->unack)) != NULL) {
		bcsp->msgq_txseq = (bcsp->msgq_txseq - 1) & 0x07;
		skb_queue_head(&bcsp->rel, skb);
	}

	spin_unlock_irqrestore(&bcsp->unack.lock, flags);

	hci_uart_tx_wakeup(hu);
}

static int bcsp_open(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp;

	BT_DBG("hu %p", hu);

	bcsp = kmalloc(sizeof(*bcsp), GFP_ATOMIC);
	if (!bcsp)
		return -ENOMEM;
	memset(bcsp, 0, sizeof(*bcsp));

	hu->priv = bcsp;
	skb_queue_head_init(&bcsp->unack);
	skb_queue_head_init(&bcsp->rel);
	skb_queue_head_init(&bcsp->unrel);

	init_timer(&bcsp->tbcsp);
	bcsp->tbcsp.function = bcsp_timed_event;
	bcsp->tbcsp.data     = (u_long) hu;

	bcsp->rx_state = BCSP_W4_PKT_DELIMITER;

	return 0;
}

static int bcsp_close(struct hci_uart *hu)
{
	struct bcsp_struct *bcsp = hu->priv;
	hu->priv = NULL;

	BT_DBG("hu %p", hu);

	skb_queue_purge(&bcsp->unack);
	skb_queue_purge(&bcsp->rel);
	skb_queue_purge(&bcsp->unrel);
	del_timer(&bcsp->tbcsp);

	kfree(bcsp);
	return 0;
}

static struct hci_uart_proto bcsp = {
	.id      = HCI_UART_BCSP,
	.open    = bcsp_open,
	.close   = bcsp_close,
	.enqueue = bcsp_enqueue,
	.dequeue = bcsp_dequeue,
	.recv    = bcsp_recv,
	.flush   = bcsp_flush
};

int bcsp_init(void)
{
	int err = hci_uart_register_proto(&bcsp);
	if (!err)
		BT_INFO("HCI BCSP protocol initialized");
	else
		BT_ERR("HCI BCSP protocol registration failed");

	return err;
}

int bcsp_deinit(void)
{
	return hci_uart_unregister_proto(&bcsp);
}

module_param(hciextn, bool, 0644);
MODULE_PARM_DESC(hciextn, "Convert HCI Extensions into BCSP packets");