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Bluetooth: Add initial sleep support to Three-wire UART
[deliverable/linux.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 #define H5_TXWINSIZE 4
37
38 #define H5_ACK_TIMEOUT msecs_to_jiffies(250)
39 #define H5_SYNC_TIMEOUT msecs_to_jiffies(100)
40
41 /*
42 * Maximum Three-wire packet:
43 * 4 byte header + max value for 12-bit length + 2 bytes for CRC
44 */
45 #define H5_MAX_LEN (4 + 0xfff + 2)
46
47 /* Convenience macros for reading Three-wire header values */
48 #define H5_HDR_SEQ(hdr) ((hdr)[0] & 0x07)
49 #define H5_HDR_ACK(hdr) (((hdr)[0] >> 3) & 0x07)
50 #define H5_HDR_CRC(hdr) (((hdr)[0] >> 6) & 0x01)
51 #define H5_HDR_RELIABLE(hdr) (((hdr)[0] >> 7) & 0x01)
52 #define H5_HDR_PKT_TYPE(hdr) ((hdr)[1] & 0x0f)
53 #define H5_HDR_LEN(hdr) ((((hdr)[1] >> 4) & 0xff) + ((hdr)[2] << 4))
54
55 #define SLIP_DELIMITER 0xc0
56 #define SLIP_ESC 0xdb
57 #define SLIP_ESC_DELIM 0xdc
58 #define SLIP_ESC_ESC 0xdd
59
60 struct h5 {
61 struct sk_buff_head unack; /* Unack'ed packets queue */
62 struct sk_buff_head rel; /* Reliable packets queue */
63 struct sk_buff_head unrel; /* Unreliable packets queue */
64
65 struct sk_buff *rx_skb; /* Receive buffer */
66 size_t rx_pending; /* Expecting more bytes */
67 bool rx_esc; /* SLIP escape mode */
68 u8 rx_ack; /* Last ack number received */
69
70 int (*rx_func) (struct hci_uart *hu, u8 c);
71
72 struct timer_list timer; /* Retransmission timer */
73
74 bool tx_ack_req; /* Pending ack to send */
75 u8 tx_seq; /* Next seq number to send */
76 u8 tx_ack; /* Next ack number to send */
77
78 bool sleeping;
79 };
80
81 static void h5_reset_rx(struct h5 *h5);
82
83 static void h5_timed_event(unsigned long arg)
84 {
85 struct hci_uart *hu = (struct hci_uart *) arg;
86 struct h5 *h5 = hu->priv;
87 struct sk_buff *skb;
88 unsigned long flags;
89
90 BT_DBG("hu %p retransmitting %u pkts", hu, h5->unack.qlen);
91
92 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
93
94 while ((skb = __skb_dequeue_tail(&h5->unack)) != NULL) {
95 h5->tx_seq = (h5->tx_seq - 1) & 0x07;
96 skb_queue_head(&h5->rel, skb);
97 }
98
99 spin_unlock_irqrestore(&h5->unack.lock, flags);
100
101 hci_uart_tx_wakeup(hu);
102 }
103
104 static void h5_link_control(struct hci_uart *hu, const void *data, size_t len)
105 {
106 struct h5 *h5 = hu->priv;
107 struct sk_buff *nskb;
108
109 nskb = alloc_skb(3, GFP_ATOMIC);
110 if (!nskb)
111 return;
112
113 bt_cb(nskb)->pkt_type = HCI_3WIRE_LINK_PKT;
114
115 memcpy(skb_put(nskb, len), data, len);
116
117 skb_queue_tail(&h5->unrel, nskb);
118 }
119
120 static int h5_open(struct hci_uart *hu)
121 {
122 struct h5 *h5;
123 const unsigned char sync[] = { 0x01, 0x7e };
124
125 BT_DBG("hu %p", hu);
126
127 h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
128 if (!h5)
129 return -ENOMEM;
130
131 hu->priv = h5;
132
133 skb_queue_head_init(&h5->unack);
134 skb_queue_head_init(&h5->rel);
135 skb_queue_head_init(&h5->unrel);
136
137 h5_reset_rx(h5);
138
139 init_timer(&h5->timer);
140 h5->timer.function = h5_timed_event;
141 h5->timer.data = (unsigned long) hu;
142
143 set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
144
145 /* Send initial sync request */
146 h5_link_control(hu, sync, sizeof(sync));
147 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
148
149 return 0;
150 }
151
152 static int h5_close(struct hci_uart *hu)
153 {
154 struct h5 *h5 = hu->priv;
155
156 skb_queue_purge(&h5->unack);
157 skb_queue_purge(&h5->rel);
158 skb_queue_purge(&h5->unrel);
159
160 del_timer(&h5->timer);
161
162 kfree(h5);
163
164 return 0;
165 }
166
167 static void h5_pkt_cull(struct h5 *h5)
168 {
169 struct sk_buff *skb, *tmp;
170 unsigned long flags;
171 int i, to_remove;
172 u8 seq;
173
174 spin_lock_irqsave(&h5->unack.lock, flags);
175
176 to_remove = skb_queue_len(&h5->unack);
177 if (to_remove == 0)
178 goto unlock;
179
180 seq = h5->tx_seq;
181
182 while (to_remove > 0) {
183 if (h5->rx_ack == seq)
184 break;
185
186 to_remove--;
187 seq = (seq - 1) % 8;
188 }
189
190 if (seq != h5->rx_ack)
191 BT_ERR("Controller acked invalid packet");
192
193 i = 0;
194 skb_queue_walk_safe(&h5->unack, skb, tmp) {
195 if (i++ >= to_remove)
196 break;
197
198 __skb_unlink(skb, &h5->unack);
199 kfree_skb(skb);
200 }
201
202 if (skb_queue_empty(&h5->unack))
203 del_timer(&h5->timer);
204
205 unlock:
206 spin_unlock_irqrestore(&h5->unack.lock, flags);
207 }
208
209 static void h5_handle_internal_rx(struct hci_uart *hu)
210 {
211 struct h5 *h5 = hu->priv;
212 const unsigned char sync_req[] = { 0x01, 0x7e };
213 const unsigned char sync_rsp[] = { 0x02, 0x7d };
214 const unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
215 const unsigned char conf_rsp[] = { 0x04, 0x7b, 0x01 };
216 const unsigned char wakeup_req[] = { 0x05, 0xfa };
217 const unsigned char woken_req[] = { 0x06, 0xf9 };
218 const unsigned char sleep_req[] = { 0x07, 0x78 };
219 const unsigned char *hdr = h5->rx_skb->data;
220 const unsigned char *data = &h5->rx_skb->data[4];
221
222 BT_DBG("%s", hu->hdev->name);
223
224 if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
225 return;
226
227 if (H5_HDR_LEN(hdr) < 2)
228 return;
229
230 if (memcmp(data, sync_req, 2) == 0) {
231 h5_link_control(hu, sync_rsp, 2);
232 } else if (memcmp(data, sync_rsp, 2) == 0) {
233 h5_link_control(hu, conf_req, 3);
234 } else if (memcmp(data, conf_req, 2) == 0) {
235 h5_link_control(hu, conf_rsp, 2);
236 h5_link_control(hu, conf_req, 3);
237 } else if (memcmp(data, conf_rsp, 2) == 0) {
238 BT_DBG("Three-wire init sequence complete");
239 hci_uart_init_ready(hu);
240 return;
241 } else if (memcmp(data, sleep_req, 2) == 0) {
242 BT_DBG("Peer went to sleep");
243 h5->sleeping = true;
244 h5_link_control(hu, wakeup_req, 2);
245 } else if (memcmp(data, woken_req, 2) == 0) {
246 BT_DBG("Peer woke up");
247 h5->sleeping = false;
248 return;
249 } else {
250 BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
251 return;
252 }
253
254 hci_uart_tx_wakeup(hu);
255 }
256
257 static void h5_complete_rx_pkt(struct hci_uart *hu)
258 {
259 struct h5 *h5 = hu->priv;
260 const unsigned char *hdr = h5->rx_skb->data;
261
262 if (H5_HDR_RELIABLE(hdr)) {
263 h5->tx_ack = (h5->tx_ack + 1) % 8;
264 h5->tx_ack_req = true;
265 hci_uart_tx_wakeup(hu);
266 }
267
268 h5->rx_ack = H5_HDR_ACK(hdr);
269
270 h5_pkt_cull(h5);
271
272 switch (H5_HDR_PKT_TYPE(hdr)) {
273 case HCI_EVENT_PKT:
274 case HCI_ACLDATA_PKT:
275 case HCI_SCODATA_PKT:
276 bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);
277
278 /* Remove Three-wire header */
279 skb_pull(h5->rx_skb, 4);
280
281 hci_recv_frame(h5->rx_skb);
282 h5->rx_skb = NULL;
283
284 break;
285
286 default:
287 h5_handle_internal_rx(hu);
288 break;
289 }
290
291 h5_reset_rx(h5);
292 }
293
294 static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
295 {
296 struct h5 *h5 = hu->priv;
297
298 h5_complete_rx_pkt(hu);
299 h5_reset_rx(h5);
300
301 return 0;
302 }
303
304 static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
305 {
306 struct h5 *h5 = hu->priv;
307 const unsigned char *hdr = h5->rx_skb->data;
308
309 if (H5_HDR_CRC(hdr)) {
310 h5->rx_func = h5_rx_crc;
311 h5->rx_pending = 2;
312 } else {
313 h5_complete_rx_pkt(hu);
314 h5_reset_rx(h5);
315 }
316
317 return 0;
318 }
319
320 static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
321 {
322 struct h5 *h5 = hu->priv;
323 const unsigned char *hdr = h5->rx_skb->data;
324
325 BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
326 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
327 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
328 H5_HDR_LEN(hdr));
329
330 if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
331 BT_ERR("Invalid header checksum");
332 h5_reset_rx(h5);
333 return 0;
334 }
335
336 if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
337 BT_ERR("Out-of-order packet arrived (%u != %u)",
338 H5_HDR_SEQ(hdr), h5->tx_ack);
339 h5_reset_rx(h5);
340 return 0;
341 }
342
343 h5->rx_func = h5_rx_payload;
344 h5->rx_pending = H5_HDR_LEN(hdr);
345
346 return 0;
347 }
348
349 static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
350 {
351 struct h5 *h5 = hu->priv;
352
353 if (c == SLIP_DELIMITER)
354 return 1;
355
356 h5->rx_func = h5_rx_3wire_hdr;
357 h5->rx_pending = 4;
358
359 h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
360 if (!h5->rx_skb) {
361 BT_ERR("Can't allocate mem for new packet");
362 h5_reset_rx(h5);
363 return -ENOMEM;
364 }
365
366 h5->rx_skb->dev = (void *) hu->hdev;
367
368 return 0;
369 }
370
371 static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
372 {
373 struct h5 *h5 = hu->priv;
374
375 if (c == SLIP_DELIMITER)
376 h5->rx_func = h5_rx_pkt_start;
377
378 return 1;
379 }
380
381 static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
382 {
383 const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
384 const u8 *byte = &c;
385
386 if (!h5->rx_esc && c == SLIP_ESC) {
387 h5->rx_esc = true;
388 return;
389 }
390
391 if (h5->rx_esc) {
392 switch (c) {
393 case SLIP_ESC_DELIM:
394 byte = &delim;
395 break;
396 case SLIP_ESC_ESC:
397 byte = &esc;
398 break;
399 default:
400 BT_ERR("Invalid esc byte 0x%02hhx", c);
401 h5_reset_rx(h5);
402 return;
403 }
404
405 h5->rx_esc = false;
406 }
407
408 memcpy(skb_put(h5->rx_skb, 1), byte, 1);
409 h5->rx_pending--;
410
411 BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
412 }
413
414 static void h5_reset_rx(struct h5 *h5)
415 {
416 if (h5->rx_skb) {
417 kfree_skb(h5->rx_skb);
418 h5->rx_skb = NULL;
419 }
420
421 h5->rx_func = h5_rx_delimiter;
422 h5->rx_pending = 0;
423 h5->rx_esc = false;
424 }
425
426 static int h5_recv(struct hci_uart *hu, void *data, int count)
427 {
428 struct h5 *h5 = hu->priv;
429 unsigned char *ptr = data;
430
431 BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
432 count);
433
434 while (count > 0) {
435 int processed;
436
437 if (h5->rx_pending > 0) {
438 if (*ptr == SLIP_DELIMITER) {
439 BT_ERR("Too short H5 packet");
440 h5_reset_rx(h5);
441 continue;
442 }
443
444 h5_unslip_one_byte(h5, *ptr);
445
446 ptr++; count--;
447 continue;
448 }
449
450 processed = h5->rx_func(hu, *ptr);
451 if (processed < 0)
452 return processed;
453
454 ptr += processed;
455 count -= processed;
456 }
457
458 return 0;
459 }
460
461 static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
462 {
463 struct h5 *h5 = hu->priv;
464
465 if (skb->len > 0xfff) {
466 BT_ERR("Packet too long (%u bytes)", skb->len);
467 kfree_skb(skb);
468 return 0;
469 }
470
471 switch (bt_cb(skb)->pkt_type) {
472 case HCI_ACLDATA_PKT:
473 case HCI_COMMAND_PKT:
474 skb_queue_tail(&h5->rel, skb);
475 break;
476
477 case HCI_SCODATA_PKT:
478 skb_queue_tail(&h5->unrel, skb);
479 break;
480
481 default:
482 BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
483 kfree_skb(skb);
484 break;
485 }
486
487 return 0;
488 }
489
490 static void h5_slip_delim(struct sk_buff *skb)
491 {
492 const char delim = SLIP_DELIMITER;
493
494 memcpy(skb_put(skb, 1), &delim, 1);
495 }
496
497 static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
498 {
499 const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
500 const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
501
502 switch (c) {
503 case SLIP_DELIMITER:
504 memcpy(skb_put(skb, 2), &esc_delim, 2);
505 break;
506 case SLIP_ESC:
507 memcpy(skb_put(skb, 2), &esc_esc, 2);
508 break;
509 default:
510 memcpy(skb_put(skb, 1), &c, 1);
511 }
512 }
513
514 static struct sk_buff *h5_build_pkt(struct hci_uart *hu, bool rel, u8 pkt_type,
515 const u8 *data, size_t len)
516 {
517 struct h5 *h5 = hu->priv;
518 struct sk_buff *nskb;
519 u8 hdr[4];
520 int i;
521
522 /*
523 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2
524 * (because bytes 0xc0 and 0xdb are escaped, worst case is when
525 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0
526 * delimiters at start and end).
527 */
528 nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
529 if (!nskb)
530 return NULL;
531
532 bt_cb(nskb)->pkt_type = pkt_type;
533
534 h5_slip_delim(nskb);
535
536 hdr[0] = h5->tx_ack << 3;
537 h5->tx_ack_req = false;
538
539 if (rel) {
540 hdr[0] |= 1 << 7;
541 hdr[0] |= h5->tx_seq;
542 h5->tx_seq = (h5->tx_seq + 1) % 8;
543 }
544
545 hdr[1] = pkt_type | ((len & 0x0f) << 4);
546 hdr[2] = len >> 4;
547 hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
548
549 BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
550 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
551 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
552 H5_HDR_LEN(hdr));
553
554 for (i = 0; i < 4; i++)
555 h5_slip_one_byte(nskb, hdr[i]);
556
557 for (i = 0; i < len; i++)
558 h5_slip_one_byte(nskb, data[i]);
559
560 h5_slip_delim(nskb);
561
562 return nskb;
563 }
564
565 static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
566 const u8 *data, size_t len)
567 {
568 bool rel;
569
570 switch (pkt_type) {
571 case HCI_ACLDATA_PKT:
572 case HCI_COMMAND_PKT:
573 rel = true;
574 break;
575 case HCI_SCODATA_PKT:
576 case HCI_3WIRE_LINK_PKT:
577 case HCI_3WIRE_ACK_PKT:
578 rel = false;
579 break;
580 default:
581 BT_ERR("Unknown packet type %u", pkt_type);
582 return NULL;
583 }
584
585 return h5_build_pkt(hu, rel, pkt_type, data, len);
586 }
587
588 static struct sk_buff *h5_dequeue(struct hci_uart *hu)
589 {
590 struct h5 *h5 = hu->priv;
591 unsigned long flags;
592 struct sk_buff *skb, *nskb;
593
594 if ((skb = skb_dequeue(&h5->unrel)) != NULL) {
595 nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
596 skb->data, skb->len);
597 if (nskb) {
598 kfree_skb(skb);
599 return nskb;
600 }
601
602 skb_queue_head(&h5->unrel, skb);
603 BT_ERR("Could not dequeue pkt because alloc_skb failed");
604 }
605
606 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
607
608 if (h5->unack.qlen >= H5_TXWINSIZE)
609 goto unlock;
610
611 if ((skb = skb_dequeue(&h5->rel)) != NULL) {
612 nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
613 skb->data, skb->len);
614 if (nskb) {
615 __skb_queue_tail(&h5->unack, skb);
616 mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
617 spin_unlock_irqrestore(&h5->unack.lock, flags);
618 return nskb;
619 }
620
621 skb_queue_head(&h5->rel, skb);
622 BT_ERR("Could not dequeue pkt because alloc_skb failed");
623 }
624
625 unlock:
626 spin_unlock_irqrestore(&h5->unack.lock, flags);
627
628 if (h5->tx_ack_req)
629 return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
630
631 return NULL;
632 }
633
634 static int h5_flush(struct hci_uart *hu)
635 {
636 BT_DBG("hu %p", hu);
637 return 0;
638 }
639
640 static struct hci_uart_proto h5p = {
641 .id = HCI_UART_3WIRE,
642 .open = h5_open,
643 .close = h5_close,
644 .recv = h5_recv,
645 .enqueue = h5_enqueue,
646 .dequeue = h5_dequeue,
647 .flush = h5_flush,
648 };
649
650 int __init h5_init(void)
651 {
652 int err = hci_uart_register_proto(&h5p);
653
654 if (!err)
655 BT_INFO("HCI Three-wire UART (H5) protocol initialized");
656 else
657 BT_ERR("HCI Three-wire UART (H5) protocol init failed");
658
659 return err;
660 }
661
662 int __exit h5_deinit(void)
663 {
664 return hci_uart_unregister_proto(&h5p);
665 }
Linux kernel - Deliverables
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