xref: /openbmc/linux/drivers/bluetooth/hci_bcsp.c (revision f3539c12)
1 /*
2  *
3  *  Bluetooth HCI UART driver
4  *
5  *  Copyright (C) 2002-2003  Fabrizio Gennari <fabrizio.gennari@philips.com>
6  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
7  *
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or
12  *  (at your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful,
15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *  GNU General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License
20  *  along with this program; if not, write to the Free Software
21  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
22  *
23  */
24 
25 #include <linux/module.h>
26 
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/types.h>
30 #include <linux/fcntl.h>
31 #include <linux/interrupt.h>
32 #include <linux/ptrace.h>
33 #include <linux/poll.h>
34 
35 #include <linux/slab.h>
36 #include <linux/tty.h>
37 #include <linux/errno.h>
38 #include <linux/string.h>
39 #include <linux/signal.h>
40 #include <linux/ioctl.h>
41 #include <linux/skbuff.h>
42 #include <linux/bitrev.h>
43 #include <asm/unaligned.h>
44 
45 #include <net/bluetooth/bluetooth.h>
46 #include <net/bluetooth/hci_core.h>
47 
48 #include "hci_uart.h"
49 
50 static bool txcrc = true;
51 static bool hciextn = true;
52 
53 #define BCSP_TXWINSIZE	4
54 
55 #define BCSP_ACK_PKT	0x05
56 #define BCSP_LE_PKT	0x06
57 
58 struct bcsp_struct {
59 	struct sk_buff_head unack;	/* Unack'ed packets queue */
60 	struct sk_buff_head rel;	/* Reliable packets queue */
61 	struct sk_buff_head unrel;	/* Unreliable packets queue */
62 
63 	unsigned long rx_count;
64 	struct	sk_buff *rx_skb;
65 	u8	rxseq_txack;		/* rxseq == txack. */
66 	u8	rxack;			/* Last packet sent by us that the peer ack'ed */
67 	struct	timer_list tbcsp;
68 
69 	enum {
70 		BCSP_W4_PKT_DELIMITER,
71 		BCSP_W4_PKT_START,
72 		BCSP_W4_BCSP_HDR,
73 		BCSP_W4_DATA,
74 		BCSP_W4_CRC
75 	} rx_state;
76 
77 	enum {
78 		BCSP_ESCSTATE_NOESC,
79 		BCSP_ESCSTATE_ESC
80 	} rx_esc_state;
81 
82 	u8	use_crc;
83 	u16	message_crc;
84 	u8	txack_req;		/* Do we need to send ack's to the peer? */
85 
86 	/* Reliable packet sequence number - used to assign seq to each rel pkt. */
87 	u8	msgq_txseq;
88 };
89 
90 /* ---- BCSP CRC calculation ---- */
91 
92 /* Table for calculating CRC for polynomial 0x1021, LSB processed first,
93 initial value 0xffff, bits shifted in reverse order. */
94 
95 static const u16 crc_table[] = {
96 	0x0000, 0x1081, 0x2102, 0x3183,
97 	0x4204, 0x5285, 0x6306, 0x7387,
98 	0x8408, 0x9489, 0xa50a, 0xb58b,
99 	0xc60c, 0xd68d, 0xe70e, 0xf78f
100 };
101 
102 /* Initialise the crc calculator */
103 #define BCSP_CRC_INIT(x) x = 0xffff
104 
105 /* Update crc with next data byte
106  *
107  * Implementation note
108  *     The data byte is treated as two nibbles.  The crc is generated
109  *     in reverse, i.e., bits are fed into the register from the top.
110  */
111 static void bcsp_crc_update(u16 *crc, u8 d)
112 {
113 	u16 reg = *crc;
114 
115 	reg = (reg >> 4) ^ crc_table[(reg ^ d) & 0x000f];
116 	reg = (reg >> 4) ^ crc_table[(reg ^ (d >> 4)) & 0x000f];
117 
118 	*crc = reg;
119 }
120 
121 /* ---- BCSP core ---- */
122 
123 static void bcsp_slip_msgdelim(struct sk_buff *skb)
124 {
125 	const char pkt_delim = 0xc0;
126 
127 	memcpy(skb_put(skb, 1), &pkt_delim, 1);
128 }
129 
130 static void bcsp_slip_one_byte(struct sk_buff *skb, u8 c)
131 {
132 	const char esc_c0[2] = { 0xdb, 0xdc };
133 	const char esc_db[2] = { 0xdb, 0xdd };
134 
135 	switch (c) {
136 	case 0xc0:
137 		memcpy(skb_put(skb, 2), &esc_c0, 2);
138 		break;
139 	case 0xdb:
140 		memcpy(skb_put(skb, 2), &esc_db, 2);
141 		break;
142 	default:
143 		memcpy(skb_put(skb, 1), &c, 1);
144 	}
145 }
146 
147 static int bcsp_enqueue(struct hci_uart *hu, struct sk_buff *skb)
148 {
149 	struct bcsp_struct *bcsp = hu->priv;
150 
151 	if (skb->len > 0xFFF) {
152 		BT_ERR("Packet too long");
153 		kfree_skb(skb);
154 		return 0;
155 	}
156 
157 	switch (hci_skb_pkt_type(skb)) {
158 	case HCI_ACLDATA_PKT:
159 	case HCI_COMMAND_PKT:
160 		skb_queue_tail(&bcsp->rel, skb);
161 		break;
162 
163 	case HCI_SCODATA_PKT:
164 		skb_queue_tail(&bcsp->unrel, skb);
165 		break;
166 
167 	default:
168 		BT_ERR("Unknown packet type");
169 		kfree_skb(skb);
170 		break;
171 	}
172 
173 	return 0;
174 }
175 
176 static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
177 		int len, int pkt_type)
178 {
179 	struct sk_buff *nskb;
180 	u8 hdr[4], chan;
181 	u16 BCSP_CRC_INIT(bcsp_txmsg_crc);
182 	int rel, i;
183 
184 	switch (pkt_type) {
185 	case HCI_ACLDATA_PKT:
186 		chan = 6;	/* BCSP ACL channel */
187 		rel = 1;	/* reliable channel */
188 		break;
189 	case HCI_COMMAND_PKT:
190 		chan = 5;	/* BCSP cmd/evt channel */
191 		rel = 1;	/* reliable channel */
192 		break;
193 	case HCI_SCODATA_PKT:
194 		chan = 7;	/* BCSP SCO channel */
195 		rel = 0;	/* unreliable channel */
196 		break;
197 	case BCSP_LE_PKT:
198 		chan = 1;	/* BCSP LE channel */
199 		rel = 0;	/* unreliable channel */
200 		break;
201 	case BCSP_ACK_PKT:
202 		chan = 0;	/* BCSP internal channel */
203 		rel = 0;	/* unreliable channel */
204 		break;
205 	default:
206 		BT_ERR("Unknown packet type");
207 		return NULL;
208 	}
209 
210 	if (hciextn && chan == 5) {
211 		__le16 opcode = ((struct hci_command_hdr *)data)->opcode;
212 
213 		/* Vendor specific commands */
214 		if (hci_opcode_ogf(__le16_to_cpu(opcode)) == 0x3f) {
215 			u8 desc = *(data + HCI_COMMAND_HDR_SIZE);
216 			if ((desc & 0xf0) == 0xc0) {
217 				data += HCI_COMMAND_HDR_SIZE + 1;
218 				len  -= HCI_COMMAND_HDR_SIZE + 1;
219 				chan = desc & 0x0f;
220 			}
221 		}
222 	}
223 
224 	/* Max len of packet: (original len +4(bcsp hdr) +2(crc))*2
225 	 * (because bytes 0xc0 and 0xdb are escaped, worst case is
226 	 * when the packet is all made of 0xc0 and 0xdb :) )
227 	 * + 2 (0xc0 delimiters at start and end).
228 	 */
229 
230 	nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
231 	if (!nskb)
232 		return NULL;
233 
234 	hci_skb_pkt_type(nskb) = pkt_type;
235 
236 	bcsp_slip_msgdelim(nskb);
237 
238 	hdr[0] = bcsp->rxseq_txack << 3;
239 	bcsp->txack_req = 0;
240 	BT_DBG("We request packet no %u to card", bcsp->rxseq_txack);
241 
242 	if (rel) {
243 		hdr[0] |= 0x80 + bcsp->msgq_txseq;
244 		BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq);
245 		bcsp->msgq_txseq = (bcsp->msgq_txseq + 1) & 0x07;
246 	}
247 
248 	if (bcsp->use_crc)
249 		hdr[0] |= 0x40;
250 
251 	hdr[1] = ((len << 4) & 0xff) | chan;
252 	hdr[2] = len >> 4;
253 	hdr[3] = ~(hdr[0] + hdr[1] + hdr[2]);
254 
255 	/* Put BCSP header */
256 	for (i = 0; i < 4; i++) {
257 		bcsp_slip_one_byte(nskb, hdr[i]);
258 
259 		if (bcsp->use_crc)
260 			bcsp_crc_update(&bcsp_txmsg_crc, hdr[i]);
261 	}
262 
263 	/* Put payload */
264 	for (i = 0; i < len; i++) {
265 		bcsp_slip_one_byte(nskb, data[i]);
266 
267 		if (bcsp->use_crc)
268 			bcsp_crc_update(&bcsp_txmsg_crc, data[i]);
269 	}
270 
271 	/* Put CRC */
272 	if (bcsp->use_crc) {
273 		bcsp_txmsg_crc = bitrev16(bcsp_txmsg_crc);
274 		bcsp_slip_one_byte(nskb, (u8) ((bcsp_txmsg_crc >> 8) & 0x00ff));
275 		bcsp_slip_one_byte(nskb, (u8) (bcsp_txmsg_crc & 0x00ff));
276 	}
277 
278 	bcsp_slip_msgdelim(nskb);
279 	return nskb;
280 }
281 
282 /* This is a rewrite of pkt_avail in ABCSP */
283 static struct sk_buff *bcsp_dequeue(struct hci_uart *hu)
284 {
285 	struct bcsp_struct *bcsp = hu->priv;
286 	unsigned long flags;
287 	struct sk_buff *skb;
288 
289 	/* First of all, check for unreliable messages in the queue,
290 	   since they have priority */
291 
292 	skb = skb_dequeue(&bcsp->unrel);
293 	if (skb != NULL) {
294 		struct sk_buff *nskb;
295 
296 		nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len,
297 					hci_skb_pkt_type(skb));
298 		if (nskb) {
299 			kfree_skb(skb);
300 			return nskb;
301 		} else {
302 			skb_queue_head(&bcsp->unrel, skb);
303 			BT_ERR("Could not dequeue pkt because alloc_skb failed");
304 		}
305 	}
306 
307 	/* Now, try to send a reliable pkt. We can only send a
308 	 * reliable packet if the number of packets sent but not yet ack'ed
309 	 * is < than the winsize
310 	 */
311 
312 	spin_lock_irqsave_nested(&bcsp->unack.lock, flags, SINGLE_DEPTH_NESTING);
313 
314 	if (bcsp->unack.qlen < BCSP_TXWINSIZE) {
315 		skb = skb_dequeue(&bcsp->rel);
316 		if (skb != NULL) {
317 			struct sk_buff *nskb;
318 
319 			nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len,
320 						hci_skb_pkt_type(skb));
321 			if (nskb) {
322 				__skb_queue_tail(&bcsp->unack, skb);
323 				mod_timer(&bcsp->tbcsp, jiffies + HZ / 4);
324 				spin_unlock_irqrestore(&bcsp->unack.lock, flags);
325 				return nskb;
326 			} else {
327 				skb_queue_head(&bcsp->rel, skb);
328 				BT_ERR("Could not dequeue pkt because alloc_skb failed");
329 			}
330 		}
331 	}
332 
333 	spin_unlock_irqrestore(&bcsp->unack.lock, flags);
334 
335 	/* We could not send a reliable packet, either because there are
336 	 * none or because there are too many unack'ed pkts. Did we receive
337 	 * any packets we have not acknowledged yet ?
338 	 */
339 
340 	if (bcsp->txack_req) {
341 		/* if so, craft an empty ACK pkt and send it on BCSP unreliable
342 		 * channel 0
343 		 */
344 		struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, NULL, 0, BCSP_ACK_PKT);
345 		return nskb;
346 	}
347 
348 	/* We have nothing to send */
349 	return NULL;
350 }
351 
352 static int bcsp_flush(struct hci_uart *hu)
353 {
354 	BT_DBG("hu %p", hu);
355 	return 0;
356 }
357 
358 /* Remove ack'ed packets */
359 static void bcsp_pkt_cull(struct bcsp_struct *bcsp)
360 {
361 	struct sk_buff *skb, *tmp;
362 	unsigned long flags;
363 	int i, pkts_to_be_removed;
364 	u8 seqno;
365 
366 	spin_lock_irqsave(&bcsp->unack.lock, flags);
367 
368 	pkts_to_be_removed = skb_queue_len(&bcsp->unack);
369 	seqno = bcsp->msgq_txseq;
370 
371 	while (pkts_to_be_removed) {
372 		if (bcsp->rxack == seqno)
373 			break;
374 		pkts_to_be_removed--;
375 		seqno = (seqno - 1) & 0x07;
376 	}
377 
378 	if (bcsp->rxack != seqno)
379 		BT_ERR("Peer acked invalid packet");
380 
381 	BT_DBG("Removing %u pkts out of %u, up to seqno %u",
382 	       pkts_to_be_removed, skb_queue_len(&bcsp->unack),
383 	       (seqno - 1) & 0x07);
384 
385 	i = 0;
386 	skb_queue_walk_safe(&bcsp->unack, skb, tmp) {
387 		if (i >= pkts_to_be_removed)
388 			break;
389 		i++;
390 
391 		__skb_unlink(skb, &bcsp->unack);
392 		kfree_skb(skb);
393 	}
394 
395 	if (skb_queue_empty(&bcsp->unack))
396 		del_timer(&bcsp->tbcsp);
397 
398 	spin_unlock_irqrestore(&bcsp->unack.lock, flags);
399 
400 	if (i != pkts_to_be_removed)
401 		BT_ERR("Removed only %u out of %u pkts", i, pkts_to_be_removed);
402 }
403 
404 /* Handle BCSP link-establishment packets. When we
405  * detect a "sync" packet, symptom that the BT module has reset,
406  * we do nothing :) (yet)
407  */
408 static void bcsp_handle_le_pkt(struct hci_uart *hu)
409 {
410 	struct bcsp_struct *bcsp = hu->priv;
411 	u8 conf_pkt[4]     = { 0xad, 0xef, 0xac, 0xed };
412 	u8 conf_rsp_pkt[4] = { 0xde, 0xad, 0xd0, 0xd0 };
413 	u8 sync_pkt[4]     = { 0xda, 0xdc, 0xed, 0xed };
414 
415 	/* spot "conf" pkts and reply with a "conf rsp" pkt */
416 	if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
417 			!memcmp(&bcsp->rx_skb->data[4], conf_pkt, 4)) {
418 		struct sk_buff *nskb = alloc_skb(4, GFP_ATOMIC);
419 
420 		BT_DBG("Found a LE conf pkt");
421 		if (!nskb)
422 			return;
423 		memcpy(skb_put(nskb, 4), conf_rsp_pkt, 4);
424 		hci_skb_pkt_type(nskb) = BCSP_LE_PKT;
425 
426 		skb_queue_head(&bcsp->unrel, nskb);
427 		hci_uart_tx_wakeup(hu);
428 	}
429 	/* Spot "sync" pkts. If we find one...disaster! */
430 	else if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
431 			!memcmp(&bcsp->rx_skb->data[4], sync_pkt, 4)) {
432 		BT_ERR("Found a LE sync pkt, card has reset");
433 	}
434 }
435 
436 static inline void bcsp_unslip_one_byte(struct bcsp_struct *bcsp, unsigned char byte)
437 {
438 	const u8 c0 = 0xc0, db = 0xdb;
439 
440 	switch (bcsp->rx_esc_state) {
441 	case BCSP_ESCSTATE_NOESC:
442 		switch (byte) {
443 		case 0xdb:
444 			bcsp->rx_esc_state = BCSP_ESCSTATE_ESC;
445 			break;
446 		default:
447 			memcpy(skb_put(bcsp->rx_skb, 1), &byte, 1);
448 			if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
449 					bcsp->rx_state != BCSP_W4_CRC)
450 				bcsp_crc_update(&bcsp->message_crc, byte);
451 			bcsp->rx_count--;
452 		}
453 		break;
454 
455 	case BCSP_ESCSTATE_ESC:
456 		switch (byte) {
457 		case 0xdc:
458 			memcpy(skb_put(bcsp->rx_skb, 1), &c0, 1);
459 			if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
460 					bcsp->rx_state != BCSP_W4_CRC)
461 				bcsp_crc_update(&bcsp->message_crc, 0xc0);
462 			bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
463 			bcsp->rx_count--;
464 			break;
465 
466 		case 0xdd:
467 			memcpy(skb_put(bcsp->rx_skb, 1), &db, 1);
468 			if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
469 					bcsp->rx_state != BCSP_W4_CRC)
470 				bcsp_crc_update(&bcsp->message_crc, 0xdb);
471 			bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
472 			bcsp->rx_count--;
473 			break;
474 
475 		default:
476 			BT_ERR("Invalid byte %02x after esc byte", byte);
477 			kfree_skb(bcsp->rx_skb);
478 			bcsp->rx_skb = NULL;
479 			bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
480 			bcsp->rx_count = 0;
481 		}
482 	}
483 }
484 
485 static void bcsp_complete_rx_pkt(struct hci_uart *hu)
486 {
487 	struct bcsp_struct *bcsp = hu->priv;
488 	int pass_up;
489 
490 	if (bcsp->rx_skb->data[0] & 0x80) {	/* reliable pkt */
491 		BT_DBG("Received seqno %u from card", bcsp->rxseq_txack);
492 		bcsp->rxseq_txack++;
493 		bcsp->rxseq_txack %= 0x8;
494 		bcsp->txack_req    = 1;
495 
496 		/* If needed, transmit an ack pkt */
497 		hci_uart_tx_wakeup(hu);
498 	}
499 
500 	bcsp->rxack = (bcsp->rx_skb->data[0] >> 3) & 0x07;
501 	BT_DBG("Request for pkt %u from card", bcsp->rxack);
502 
503 	bcsp_pkt_cull(bcsp);
504 	if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
505 			bcsp->rx_skb->data[0] & 0x80) {
506 		hci_skb_pkt_type(bcsp->rx_skb) = HCI_ACLDATA_PKT;
507 		pass_up = 1;
508 	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
509 			bcsp->rx_skb->data[0] & 0x80) {
510 		hci_skb_pkt_type(bcsp->rx_skb) = HCI_EVENT_PKT;
511 		pass_up = 1;
512 	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
513 		hci_skb_pkt_type(bcsp->rx_skb) = HCI_SCODATA_PKT;
514 		pass_up = 1;
515 	} else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
516 			!(bcsp->rx_skb->data[0] & 0x80)) {
517 		bcsp_handle_le_pkt(hu);
518 		pass_up = 0;
519 	} else
520 		pass_up = 0;
521 
522 	if (!pass_up) {
523 		struct hci_event_hdr hdr;
524 		u8 desc = (bcsp->rx_skb->data[1] & 0x0f);
525 
526 		if (desc != 0 && desc != 1) {
527 			if (hciextn) {
528 				desc |= 0xc0;
529 				skb_pull(bcsp->rx_skb, 4);
530 				memcpy(skb_push(bcsp->rx_skb, 1), &desc, 1);
531 
532 				hdr.evt = 0xff;
533 				hdr.plen = bcsp->rx_skb->len;
534 				memcpy(skb_push(bcsp->rx_skb, HCI_EVENT_HDR_SIZE), &hdr, HCI_EVENT_HDR_SIZE);
535 				hci_skb_pkt_type(bcsp->rx_skb) = HCI_EVENT_PKT;
536 
537 				hci_recv_frame(hu->hdev, bcsp->rx_skb);
538 			} else {
539 				BT_ERR("Packet for unknown channel (%u %s)",
540 					bcsp->rx_skb->data[1] & 0x0f,
541 					bcsp->rx_skb->data[0] & 0x80 ?
542 					"reliable" : "unreliable");
543 				kfree_skb(bcsp->rx_skb);
544 			}
545 		} else
546 			kfree_skb(bcsp->rx_skb);
547 	} else {
548 		/* Pull out BCSP hdr */
549 		skb_pull(bcsp->rx_skb, 4);
550 
551 		hci_recv_frame(hu->hdev, bcsp->rx_skb);
552 	}
553 
554 	bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
555 	bcsp->rx_skb = NULL;
556 }
557 
558 static u16 bscp_get_crc(struct bcsp_struct *bcsp)
559 {
560 	return get_unaligned_be16(&bcsp->rx_skb->data[bcsp->rx_skb->len - 2]);
561 }
562 
563 /* Recv data */
564 static int bcsp_recv(struct hci_uart *hu, const void *data, int count)
565 {
566 	struct bcsp_struct *bcsp = hu->priv;
567 	const unsigned char *ptr;
568 
569 	BT_DBG("hu %p count %d rx_state %d rx_count %ld",
570 		hu, count, bcsp->rx_state, bcsp->rx_count);
571 
572 	ptr = data;
573 	while (count) {
574 		if (bcsp->rx_count) {
575 			if (*ptr == 0xc0) {
576 				BT_ERR("Short BCSP packet");
577 				kfree_skb(bcsp->rx_skb);
578 				bcsp->rx_state = BCSP_W4_PKT_START;
579 				bcsp->rx_count = 0;
580 			} else
581 				bcsp_unslip_one_byte(bcsp, *ptr);
582 
583 			ptr++; count--;
584 			continue;
585 		}
586 
587 		switch (bcsp->rx_state) {
588 		case BCSP_W4_BCSP_HDR:
589 			if ((0xff & (u8) ~ (bcsp->rx_skb->data[0] + bcsp->rx_skb->data[1] +
590 					bcsp->rx_skb->data[2])) != bcsp->rx_skb->data[3]) {
591 				BT_ERR("Error in BCSP hdr checksum");
592 				kfree_skb(bcsp->rx_skb);
593 				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
594 				bcsp->rx_count = 0;
595 				continue;
596 			}
597 			if (bcsp->rx_skb->data[0] & 0x80	/* reliable pkt */
598 						&& (bcsp->rx_skb->data[0] & 0x07) != bcsp->rxseq_txack) {
599 				BT_ERR("Out-of-order packet arrived, got %u expected %u",
600 					bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);
601 
602 				kfree_skb(bcsp->rx_skb);
603 				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
604 				bcsp->rx_count = 0;
605 				continue;
606 			}
607 			bcsp->rx_state = BCSP_W4_DATA;
608 			bcsp->rx_count = (bcsp->rx_skb->data[1] >> 4) +
609 					(bcsp->rx_skb->data[2] << 4);	/* May be 0 */
610 			continue;
611 
612 		case BCSP_W4_DATA:
613 			if (bcsp->rx_skb->data[0] & 0x40) {	/* pkt with crc */
614 				bcsp->rx_state = BCSP_W4_CRC;
615 				bcsp->rx_count = 2;
616 			} else
617 				bcsp_complete_rx_pkt(hu);
618 			continue;
619 
620 		case BCSP_W4_CRC:
621 			if (bitrev16(bcsp->message_crc) != bscp_get_crc(bcsp)) {
622 				BT_ERR("Checksum failed: computed %04x received %04x",
623 					bitrev16(bcsp->message_crc),
624 					bscp_get_crc(bcsp));
625 
626 				kfree_skb(bcsp->rx_skb);
627 				bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
628 				bcsp->rx_count = 0;
629 				continue;
630 			}
631 			skb_trim(bcsp->rx_skb, bcsp->rx_skb->len - 2);
632 			bcsp_complete_rx_pkt(hu);
633 			continue;
634 
635 		case BCSP_W4_PKT_DELIMITER:
636 			switch (*ptr) {
637 			case 0xc0:
638 				bcsp->rx_state = BCSP_W4_PKT_START;
639 				break;
640 			default:
641 				/*BT_ERR("Ignoring byte %02x", *ptr);*/
642 				break;
643 			}
644 			ptr++; count--;
645 			break;
646 
647 		case BCSP_W4_PKT_START:
648 			switch (*ptr) {
649 			case 0xc0:
650 				ptr++; count--;
651 				break;
652 
653 			default:
654 				bcsp->rx_state = BCSP_W4_BCSP_HDR;
655 				bcsp->rx_count = 4;
656 				bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
657 				BCSP_CRC_INIT(bcsp->message_crc);
658 
659 				/* Do not increment ptr or decrement count
660 				 * Allocate packet. Max len of a BCSP pkt=
661 				 * 0xFFF (payload) +4 (header) +2 (crc)
662 				 */
663 
664 				bcsp->rx_skb = bt_skb_alloc(0x1005, GFP_ATOMIC);
665 				if (!bcsp->rx_skb) {
666 					BT_ERR("Can't allocate mem for new packet");
667 					bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
668 					bcsp->rx_count = 0;
669 					return 0;
670 				}
671 				break;
672 			}
673 			break;
674 		}
675 	}
676 	return count;
677 }
678 
679 	/* Arrange to retransmit all messages in the relq. */
680 static void bcsp_timed_event(unsigned long arg)
681 {
682 	struct hci_uart *hu = (struct hci_uart *) arg;
683 	struct bcsp_struct *bcsp = hu->priv;
684 	struct sk_buff *skb;
685 	unsigned long flags;
686 
687 	BT_DBG("hu %p retransmitting %u pkts", hu, bcsp->unack.qlen);
688 
689 	spin_lock_irqsave_nested(&bcsp->unack.lock, flags, SINGLE_DEPTH_NESTING);
690 
691 	while ((skb = __skb_dequeue_tail(&bcsp->unack)) != NULL) {
692 		bcsp->msgq_txseq = (bcsp->msgq_txseq - 1) & 0x07;
693 		skb_queue_head(&bcsp->rel, skb);
694 	}
695 
696 	spin_unlock_irqrestore(&bcsp->unack.lock, flags);
697 
698 	hci_uart_tx_wakeup(hu);
699 }
700 
701 static int bcsp_open(struct hci_uart *hu)
702 {
703 	struct bcsp_struct *bcsp;
704 
705 	BT_DBG("hu %p", hu);
706 
707 	bcsp = kzalloc(sizeof(*bcsp), GFP_KERNEL);
708 	if (!bcsp)
709 		return -ENOMEM;
710 
711 	hu->priv = bcsp;
712 	skb_queue_head_init(&bcsp->unack);
713 	skb_queue_head_init(&bcsp->rel);
714 	skb_queue_head_init(&bcsp->unrel);
715 
716 	init_timer(&bcsp->tbcsp);
717 	bcsp->tbcsp.function = bcsp_timed_event;
718 	bcsp->tbcsp.data     = (u_long) hu;
719 
720 	bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
721 
722 	if (txcrc)
723 		bcsp->use_crc = 1;
724 
725 	return 0;
726 }
727 
728 static int bcsp_close(struct hci_uart *hu)
729 {
730 	struct bcsp_struct *bcsp = hu->priv;
731 
732 	del_timer_sync(&bcsp->tbcsp);
733 
734 	hu->priv = NULL;
735 
736 	BT_DBG("hu %p", hu);
737 
738 	skb_queue_purge(&bcsp->unack);
739 	skb_queue_purge(&bcsp->rel);
740 	skb_queue_purge(&bcsp->unrel);
741 
742 	kfree(bcsp);
743 	return 0;
744 }
745 
746 static const struct hci_uart_proto bcsp = {
747 	.id		= HCI_UART_BCSP,
748 	.name		= "BCSP",
749 	.open		= bcsp_open,
750 	.close		= bcsp_close,
751 	.enqueue	= bcsp_enqueue,
752 	.dequeue	= bcsp_dequeue,
753 	.recv		= bcsp_recv,
754 	.flush		= bcsp_flush
755 };
756 
757 int __init bcsp_init(void)
758 {
759 	return hci_uart_register_proto(&bcsp);
760 }
761 
762 int __exit bcsp_deinit(void)
763 {
764 	return hci_uart_unregister_proto(&bcsp);
765 }
766 
767 module_param(txcrc, bool, 0644);
768 MODULE_PARM_DESC(txcrc, "Transmit CRC with every BCSP packet");
769 
770 module_param(hciextn, bool, 0644);
771 MODULE_PARM_DESC(hciextn, "Convert HCI Extensions into BCSP packets");
772