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