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[mirror_ubuntu-zesty-kernel.git] / drivers / bluetooth / hci_h5.c
1 /*
2 *
3 * Bluetooth HCI Three-wire UART driver
4 *
5 * Copyright (C) 2012 Intel Corporation
6 *
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 *
22 */
23
24 #include <linux/kernel.h>
25 #include <linux/errno.h>
26 #include <linux/skbuff.h>
27
28 #include <net/bluetooth/bluetooth.h>
29 #include <net/bluetooth/hci_core.h>
30
31 #include "hci_uart.h"
32
33 #define HCI_3WIRE_ACK_PKT 0
34 #define HCI_3WIRE_LINK_PKT 15
35
36 /* Sliding window size */
37 #define H5_TX_WIN_MAX 4
38
39 #define H5_ACK_TIMEOUT msecs_to_jiffies(250)
40 #define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
41
42 /*
43 * Maximum Three-wire packet:
44 * 4 byte header + max value for 12-bit length + 2 bytes for CRC
45 */
46 #define H5_MAX_LEN (4 + 0xfff + 2)
47
48 /* Convenience macros for reading Three-wire header values */
49 #define H5_HDR_SEQ(hdr) ((hdr)[0] & 0x07)
50 #define H5_HDR_ACK(hdr) (((hdr)[0] >> 3) & 0x07)
51 #define H5_HDR_CRC(hdr) (((hdr)[0] >> 6) & 0x01)
52 #define H5_HDR_RELIABLE(hdr) (((hdr)[0] >> 7) & 0x01)
53 #define H5_HDR_PKT_TYPE(hdr) ((hdr)[1] & 0x0f)
54 #define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0x0f) + ((hdr)[2] << 4))
55
56 #define SLIP_DELIMITER 0xc0
57 #define SLIP_ESC 0xdb
58 #define SLIP_ESC_DELIM 0xdc
59 #define SLIP_ESC_ESC 0xdd
60
61 /* H5 state flags */
62 enum {
63 H5_RX_ESC, /* SLIP escape mode */
64 H5_TX_ACK_REQ, /* Pending ack to send */
65 };
66
67 struct h5 {
68 struct sk_buff_head unack; /* Unack'ed packets queue */
69 struct sk_buff_head rel; /* Reliable packets queue */
70 struct sk_buff_head unrel; /* Unreliable packets queue */
71
72 unsigned long flags;
73
74 struct sk_buff *rx_skb; /* Receive buffer */
75 size_t rx_pending; /* Expecting more bytes */
76 u8 rx_ack; /* Last ack number received */
77
78 int (*rx_func)(struct hci_uart *hu, u8 c);
79
80 struct timer_list timer; /* Retransmission timer */
81
82 u8 tx_seq; /* Next seq number to send */
83 u8 tx_ack; /* Next ack number to send */
84 u8 tx_win; /* Sliding window size */
85
86 enum {
87 H5_UNINITIALIZED,
88 H5_INITIALIZED,
89 H5_ACTIVE,
90 } state;
91
92 enum {
93 H5_AWAKE,
94 H5_SLEEPING,
95 H5_WAKING_UP,
96 } sleep;
97 };
98
99 static void h5_reset_rx(struct h5 *h5);
100
101 static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)
102 {
103 struct h5 *h5 = hu->priv;
104 struct sk_buff *nskb;
105
106 nskb = alloc_skb(3, GFP_ATOMIC);
107 if (!nskb)
108 return;
109
110 hci_skb_pkt_type(nskb) = HCI_3WIRE_LINK_PKT;
111
112 memcpy(skb_put(nskb, len), data, len);
113
114 skb_queue_tail(&h5->unrel, nskb);
115 }
116
117 static u8 h5_cfg_field(struct h5 *h5)
118 {
119 /* Sliding window size (first 3 bits) */
120 return h5->tx_win & 0x07;
121 }
122
123 static void h5_timed_event(unsigned long arg)
124 {
125 const unsigned char sync_req[] = { 0x01, 0x7e };
126 unsigned char conf_req[3] = { 0x03, 0xfc };
127 struct hci_uart *hu = (struct hci_uart *)arg;
128 struct h5 *h5 = hu->priv;
129 struct sk_buff *skb;
130 unsigned long flags;
131
132 BT_DBG("%s", hu->hdev->name);
133
134 if (h5->state == H5_UNINITIALIZED)
135 h5_link_control(hu, sync_req, sizeof(sync_req));
136
137 if (h5->state == H5_INITIALIZED) {
138 conf_req[2] = h5_cfg_field(h5);
139 h5_link_control(hu, conf_req, sizeof(conf_req));
140 }
141
142 if (h5->state != H5_ACTIVE) {
143 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
144 goto wakeup;
145 }
146
147 if (h5->sleep != H5_AWAKE) {
148 h5->sleep = H5_SLEEPING;
149 goto wakeup;
150 }
151
152 BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
153
154 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
155
156 while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
157 h5->tx_seq = (h5->tx_seq - 1) & 0x07;
158 skb_queue_head(&h5->rel, skb);
159 }
160
161 spin_unlock_irqrestore(&h5->unack.lock, flags);
162
163 wakeup:
164 hci_uart_tx_wakeup(hu);
165 }
166
167 static void h5_peer_reset(struct hci_uart *hu)
168 {
169 struct h5 *h5 = hu->priv;
170
171 BT_ERR("Peer device has reset");
172
173 h5->state = H5_UNINITIALIZED;
174
175 del_timer(&h5->timer);
176
177 skb_queue_purge(&h5->rel);
178 skb_queue_purge(&h5->unrel);
179 skb_queue_purge(&h5->unack);
180
181 h5->tx_seq = 0;
182 h5->tx_ack = 0;
183
184 /* Send reset request to upper stack */
185 hci_reset_dev(hu->hdev);
186 }
187
188 static int h5_open(struct hci_uart *hu)
189 {
190 struct h5 *h5;
191 const unsigned char sync[] = { 0x01, 0x7e };
192
193 BT_DBG("hu %p", hu);
194
195 h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
196 if (!h5)
197 return -ENOMEM;
198
199 hu->priv = h5;
200
201 skb_queue_head_init(&h5->unack);
202 skb_queue_head_init(&h5->rel);
203 skb_queue_head_init(&h5->unrel);
204
205 h5_reset_rx(h5);
206
207 setup_timer(&h5->timer, h5_timed_event, (unsigned long)hu);
208
209 h5->tx_win = H5_TX_WIN_MAX;
210
211 set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
212
213 /* Send initial sync request */
214 h5_link_control(hu, sync, sizeof(sync));
215 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
216
217 return 0;
218 }
219
220 static int h5_close(struct hci_uart *hu)
221 {
222 struct h5 *h5 = hu->priv;
223
224 del_timer_sync(&h5->timer);
225
226 skb_queue_purge(&h5->unack);
227 skb_queue_purge(&h5->rel);
228 skb_queue_purge(&h5->unrel);
229
230 kfree(h5);
231
232 return 0;
233 }
234
235 static void h5_pkt_cull(struct h5 *h5)
236 {
237 struct sk_buff *skb, *tmp;
238 unsigned long flags;
239 int i, to_remove;
240 u8 seq;
241
242 spin_lock_irqsave(&h5->unack.lock, flags);
243
244 to_remove = skb_queue_len(&h5->unack);
245 if (to_remove == 0)
246 goto unlock;
247
248 seq = h5->tx_seq;
249
250 while (to_remove > 0) {
251 if (h5->rx_ack == seq)
252 break;
253
254 to_remove--;
255 seq = (seq - 1) & 0x07;
256 }
257
258 if (seq != h5->rx_ack)
259 BT_ERR("Controller acked invalid packet");
260
261 i = 0;
262 skb_queue_walk_safe(&h5->unack, skb, tmp) {
263 if (i++ >= to_remove)
264 break;
265
266 __skb_unlink(skb, &h5->unack);
267 kfree_skb(skb);
268 }
269
270 if (skb_queue_empty(&h5->unack))
271 del_timer(&h5->timer);
272
273 unlock:
274 spin_unlock_irqrestore(&h5->unack.lock, flags);
275 }
276
277 static void h5_handle_internal_rx(struct hci_uart *hu)
278 {
279 struct h5 *h5 = hu->priv;
280 const unsigned char sync_req[] = { 0x01, 0x7e };
281 const unsigned char sync_rsp[] = { 0x02, 0x7d };
282 unsigned char conf_req[3] = { 0x03, 0xfc };
283 const unsigned char conf_rsp[] = { 0x04, 0x7b };
284 const unsigned char wakeup_req[] = { 0x05, 0xfa };
285 const unsigned char woken_req[] = { 0x06, 0xf9 };
286 const unsigned char sleep_req[] = { 0x07, 0x78 };
287 const unsigned char *hdr = h5->rx_skb->data;
288 const unsigned char *data = &h5->rx_skb->data[4];
289
290 BT_DBG("%s", hu->hdev->name);
291
292 if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
293 return;
294
295 if (H5_HDR_LEN(hdr) < 2)
296 return;
297
298 conf_req[2] = h5_cfg_field(h5);
299
300 if (memcmp(data, sync_req, 2) == 0) {
301 if (h5->state == H5_ACTIVE)
302 h5_peer_reset(hu);
303 h5_link_control(hu, sync_rsp, 2);
304 } else if (memcmp(data, sync_rsp, 2) == 0) {
305 if (h5->state == H5_ACTIVE)
306 h5_peer_reset(hu);
307 h5->state = H5_INITIALIZED;
308 h5_link_control(hu, conf_req, 3);
309 } else if (memcmp(data, conf_req, 2) == 0) {
310 h5_link_control(hu, conf_rsp, 2);
311 h5_link_control(hu, conf_req, 3);
312 } else if (memcmp(data, conf_rsp, 2) == 0) {
313 if (H5_HDR_LEN(hdr) > 2)
314 h5->tx_win = (data[2] & 0x07);
315 BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
316 h5->state = H5_ACTIVE;
317 hci_uart_init_ready(hu);
318 return;
319 } else if (memcmp(data, sleep_req, 2) == 0) {
320 BT_DBG("Peer went to sleep");
321 h5->sleep = H5_SLEEPING;
322 return;
323 } else if (memcmp(data, woken_req, 2) == 0) {
324 BT_DBG("Peer woke up");
325 h5->sleep = H5_AWAKE;
326 } else if (memcmp(data, wakeup_req, 2) == 0) {
327 BT_DBG("Peer requested wakeup");
328 h5_link_control(hu, woken_req, 2);
329 h5->sleep = H5_AWAKE;
330 } else {
331 BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
332 return;
333 }
334
335 hci_uart_tx_wakeup(hu);
336 }
337
338 static void h5_complete_rx_pkt(struct hci_uart *hu)
339 {
340 struct h5 *h5 = hu->priv;
341 const unsigned char *hdr = h5->rx_skb->data;
342
343 if (H5_HDR_RELIABLE(hdr)) {
344 h5->tx_ack = (h5->tx_ack + 1) % 8;
345 set_bit(H5_TX_ACK_REQ, &h5->flags);
346 hci_uart_tx_wakeup(hu);
347 }
348
349 h5->rx_ack = H5_HDR_ACK(hdr);
350
351 h5_pkt_cull(h5);
352
353 switch (H5_HDR_PKT_TYPE(hdr)) {
354 case HCI_EVENT_PKT:
355 case HCI_ACLDATA_PKT:
356 case HCI_SCODATA_PKT:
357 hci_skb_pkt_type(h5->rx_skb) = H5_HDR_PKT_TYPE(hdr);
358
359 /* Remove Three-wire header */
360 skb_pull(h5->rx_skb, 4);
361
362 hci_recv_frame(hu->hdev, h5->rx_skb);
363 h5->rx_skb = NULL;
364
365 break;
366
367 default:
368 h5_handle_internal_rx(hu);
369 break;
370 }
371
372 h5_reset_rx(h5);
373 }
374
375 static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
376 {
377 h5_complete_rx_pkt(hu);
378
379 return 0;
380 }
381
382 static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
383 {
384 struct h5 *h5 = hu->priv;
385 const unsigned char *hdr = h5->rx_skb->data;
386
387 if (H5_HDR_CRC(hdr)) {
388 h5->rx_func = h5_rx_crc;
389 h5->rx_pending = 2;
390 } else {
391 h5_complete_rx_pkt(hu);
392 }
393
394 return 0;
395 }
396
397 static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
398 {
399 struct h5 *h5 = hu->priv;
400 const unsigned char *hdr = h5->rx_skb->data;
401
402 BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
403 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
404 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
405 H5_HDR_LEN(hdr));
406
407 if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
408 BT_ERR("Invalid header checksum");
409 h5_reset_rx(h5);
410 return 0;
411 }
412
413 if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
414 BT_ERR("Out-of-order packet arrived (%u != %u)",
415 H5_HDR_SEQ(hdr), h5->tx_ack);
416 h5_reset_rx(h5);
417 return 0;
418 }
419
420 if (h5->state != H5_ACTIVE &&
421 H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
422 BT_ERR("Non-link packet received in non-active state");
423 h5_reset_rx(h5);
424 return 0;
425 }
426
427 h5->rx_func = h5_rx_payload;
428 h5->rx_pending = H5_HDR_LEN(hdr);
429
430 return 0;
431 }
432
433 static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
434 {
435 struct h5 *h5 = hu->priv;
436
437 if (c == SLIP_DELIMITER)
438 return 1;
439
440 h5->rx_func = h5_rx_3wire_hdr;
441 h5->rx_pending = 4;
442
443 h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
444 if (!h5->rx_skb) {
445 BT_ERR("Can't allocate mem for new packet");
446 h5_reset_rx(h5);
447 return -ENOMEM;
448 }
449
450 h5->rx_skb->dev = (void *)hu->hdev;
451
452 return 0;
453 }
454
455 static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
456 {
457 struct h5 *h5 = hu->priv;
458
459 if (c == SLIP_DELIMITER)
460 h5->rx_func = h5_rx_pkt_start;
461
462 return 1;
463 }
464
465 static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
466 {
467 const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
468 const u8 *byte = &c;
469
470 if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
471 set_bit(H5_RX_ESC, &h5->flags);
472 return;
473 }
474
475 if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
476 switch (c) {
477 case SLIP_ESC_DELIM:
478 byte = &delim;
479 break;
480 case SLIP_ESC_ESC:
481 byte = &esc;
482 break;
483 default:
484 BT_ERR("Invalid esc byte 0x%02hhx", c);
485 h5_reset_rx(h5);
486 return;
487 }
488 }
489
490 memcpy(skb_put(h5->rx_skb, 1), byte, 1);
491 h5->rx_pending--;
492
493 BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
494 }
495
496 static void h5_reset_rx(struct h5 *h5)
497 {
498 if (h5->rx_skb) {
499 kfree_skb(h5->rx_skb);
500 h5->rx_skb = NULL;
501 }
502
503 h5->rx_func = h5_rx_delimiter;
504 h5->rx_pending = 0;
505 clear_bit(H5_RX_ESC, &h5->flags);
506 }
507
508 static int h5_recv(struct hci_uart *hu, const void *data, int count)
509 {
510 struct h5 *h5 = hu->priv;
511 const unsigned char *ptr = data;
512
513 BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
514 count);
515
516 while (count > 0) {
517 int processed;
518
519 if (h5->rx_pending > 0) {
520 if (*ptr == SLIP_DELIMITER) {
521 BT_ERR("Too short H5 packet");
522 h5_reset_rx(h5);
523 continue;
524 }
525
526 h5_unslip_one_byte(h5, *ptr);
527
528 ptr++; count--;
529 continue;
530 }
531
532 processed = h5->rx_func(hu, *ptr);
533 if (processed < 0)
534 return processed;
535
536 ptr += processed;
537 count -= processed;
538 }
539
540 return 0;
541 }
542
543 static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
544 {
545 struct h5 *h5 = hu->priv;
546
547 if (skb->len > 0xfff) {
548 BT_ERR("Packet too long (%u bytes)", skb->len);
549 kfree_skb(skb);
550 return 0;
551 }
552
553 if (h5->state != H5_ACTIVE) {
554 BT_ERR("Ignoring HCI data in non-active state");
555 kfree_skb(skb);
556 return 0;
557 }
558
559 switch (hci_skb_pkt_type(skb)) {
560 case HCI_ACLDATA_PKT:
561 case HCI_COMMAND_PKT:
562 skb_queue_tail(&h5->rel, skb);
563 break;
564
565 case HCI_SCODATA_PKT:
566 skb_queue_tail(&h5->unrel, skb);
567 break;
568
569 default:
570 BT_ERR("Unknown packet type %u", hci_skb_pkt_type(skb));
571 kfree_skb(skb);
572 break;
573 }
574
575 return 0;
576 }
577
578 static void h5_slip_delim(struct sk_buff *skb)
579 {
580 const char delim = SLIP_DELIMITER;
581
582 memcpy(skb_put(skb, 1), &delim, 1);
583 }
584
585 static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
586 {
587 const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
588 const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
589
590 switch (c) {
591 case SLIP_DELIMITER:
592 memcpy(skb_put(skb, 2), &esc_delim, 2);
593 break;
594 case SLIP_ESC:
595 memcpy(skb_put(skb, 2), &esc_esc, 2);
596 break;
597 default:
598 memcpy(skb_put(skb, 1), &c, 1);
599 }
600 }
601
602 static bool valid_packet_type(u8 type)
603 {
604 switch (type) {
605 case HCI_ACLDATA_PKT:
606 case HCI_COMMAND_PKT:
607 case HCI_SCODATA_PKT:
608 case HCI_3WIRE_LINK_PKT:
609 case HCI_3WIRE_ACK_PKT:
610 return true;
611 default:
612 return false;
613 }
614 }
615
616 static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
617 const u8 *data, size_t len)
618 {
619 struct h5 *h5 = hu->priv;
620 struct sk_buff *nskb;
621 u8 hdr[4];
622 int i;
623
624 if (!valid_packet_type(pkt_type)) {
625 BT_ERR("Unknown packet type %u", pkt_type);
626 return NULL;
627 }
628
629 /*
630 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
631 * (because bytes 0xc0 and 0xdb are escaped, worst case is when
632 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
633 * delimiters at start and end).
634 */
635 nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
636 if (!nskb)
637 return NULL;
638
639 hci_skb_pkt_type(nskb) = pkt_type;
640
641 h5_slip_delim(nskb);
642
643 hdr[0] = h5->tx_ack << 3;
644 clear_bit(H5_TX_ACK_REQ, &h5->flags);
645
646 /* Reliable packet? */
647 if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) {
648 hdr[0] |= 1 << 7;
649 hdr[0] |= h5->tx_seq;
650 h5->tx_seq = (h5->tx_seq + 1) % 8;
651 }
652
653 hdr[1] = pkt_type | ((len & 0x0f) << 4);
654 hdr[2] = len >> 4;
655 hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
656
657 BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
658 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
659 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
660 H5_HDR_LEN(hdr));
661
662 for (i = 0; i < 4; i++)
663 h5_slip_one_byte(nskb, hdr[i]);
664
665 for (i = 0; i < len; i++)
666 h5_slip_one_byte(nskb, data[i]);
667
668 h5_slip_delim(nskb);
669
670 return nskb;
671 }
672
673 static struct sk_buff *h5_dequeue(struct hci_uart *hu)
674 {
675 struct h5 *h5 = hu->priv;
676 unsigned long flags;
677 struct sk_buff *skb, *nskb;
678
679 if (h5->sleep != H5_AWAKE) {
680 const unsigned char wakeup_req[] = { 0x05, 0xfa };
681
682 if (h5->sleep == H5_WAKING_UP)
683 return NULL;
684
685 h5->sleep = H5_WAKING_UP;
686 BT_DBG("Sending wakeup request");
687
688 mod_timer(&h5->timer, jiffies + HZ / 100);
689 return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
690 }
691
692 skb = skb_dequeue(&h5->unrel);
693 if (skb) {
694 nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
695 skb->data, skb->len);
696 if (nskb) {
697 kfree_skb(skb);
698 return nskb;
699 }
700
701 skb_queue_head(&h5->unrel, skb);
702 BT_ERR("Could not dequeue pkt because alloc_skb failed");
703 }
704
705 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
706
707 if (h5->unack.qlen >= h5->tx_win)
708 goto unlock;
709
710 skb = skb_dequeue(&h5->rel);
711 if (skb) {
712 nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb),
713 skb->data, skb->len);
714 if (nskb) {
715 __skb_queue_tail(&h5->unack, skb);
716 mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
717 spin_unlock_irqrestore(&h5->unack.lock, flags);
718 return nskb;
719 }
720
721 skb_queue_head(&h5->rel, skb);
722 BT_ERR("Could not dequeue pkt because alloc_skb failed");
723 }
724
725 unlock:
726 spin_unlock_irqrestore(&h5->unack.lock, flags);
727
728 if (test_bit(H5_TX_ACK_REQ, &h5->flags))
729 return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
730
731 return NULL;
732 }
733
734 static int h5_flush(struct hci_uart *hu)
735 {
736 BT_DBG("hu %p", hu);
737 return 0;
738 }
739
740 static const struct hci_uart_proto h5p = {
741 .id = HCI_UART_3WIRE,
742 .name = "Three-wire (H5)",
743 .open = h5_open,
744 .close = h5_close,
745 .recv = h5_recv,
746 .enqueue = h5_enqueue,
747 .dequeue = h5_dequeue,
748 .flush = h5_flush,
749 };
750
751 int __init h5_init(void)
752 {
753 return hci_uart_register_proto(&h5p);
754 }
755
756 int __exit h5_deinit(void)
757 {
758 return hci_uart_unregister_proto(&h5p);
759 }
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