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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 void h5_peer_reset(struct hci_uart *hu)
172{
173 struct h5 *h5 = hu->priv;
174
175 BT_ERR("Peer device has reset");
176
177 h5->state = H5_UNINITIALIZED;
178
179 del_timer(&h5->timer);
180
181 skb_queue_purge(&h5->rel);
182 skb_queue_purge(&h5->unrel);
183 skb_queue_purge(&h5->unack);
184
185 h5->tx_seq = 0;
186 h5->tx_ack = 0;
187
188
189 hci_reset_dev(hu->hdev);
190}
191
192static int h5_open(struct hci_uart *hu)
193{
194 struct h5 *h5;
195 const unsigned char sync[] = { 0x01, 0x7e };
196
197 BT_DBG("hu %p", hu);
198
199 h5 = kzalloc(sizeof(*h5), GFP_KERNEL);
200 if (!h5)
201 return -ENOMEM;
202
203 hu->priv = h5;
204
205 skb_queue_head_init(&h5->unack);
206 skb_queue_head_init(&h5->rel);
207 skb_queue_head_init(&h5->unrel);
208
209 h5_reset_rx(h5);
210
211 init_timer(&h5->timer);
212 h5->timer.function = h5_timed_event;
213 h5->timer.data = (unsigned long) hu;
214
215 h5->tx_win = H5_TX_WIN_MAX;
216
217 set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags);
218
219
220 h5_link_control(hu, sync, sizeof(sync));
221 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT);
222
223 return 0;
224}
225
226static int h5_close(struct hci_uart *hu)
227{
228 struct h5 *h5 = hu->priv;
229
230 del_timer_sync(&h5->timer);
231
232 skb_queue_purge(&h5->unack);
233 skb_queue_purge(&h5->rel);
234 skb_queue_purge(&h5->unrel);
235
236 kfree(h5);
237
238 return 0;
239}
240
241static void h5_pkt_cull(struct h5 *h5)
242{
243 struct sk_buff *skb, *tmp;
244 unsigned long flags;
245 int i, to_remove;
246 u8 seq;
247
248 spin_lock_irqsave(&h5->unack.lock, flags);
249
250 to_remove = skb_queue_len(&h5->unack);
251 if (to_remove == 0)
252 goto unlock;
253
254 seq = h5->tx_seq;
255
256 while (to_remove > 0) {
257 if (h5->rx_ack == seq)
258 break;
259
260 to_remove--;
261 seq = (seq - 1) & 0x07;
262 }
263
264 if (seq != h5->rx_ack)
265 BT_ERR("Controller acked invalid packet");
266
267 i = 0;
268 skb_queue_walk_safe(&h5->unack, skb, tmp) {
269 if (i++ >= to_remove)
270 break;
271
272 __skb_unlink(skb, &h5->unack);
273 kfree_skb(skb);
274 }
275
276 if (skb_queue_empty(&h5->unack))
277 del_timer(&h5->timer);
278
279unlock:
280 spin_unlock_irqrestore(&h5->unack.lock, flags);
281}
282
283static void h5_handle_internal_rx(struct hci_uart *hu)
284{
285 struct h5 *h5 = hu->priv;
286 const unsigned char sync_req[] = { 0x01, 0x7e };
287 const unsigned char sync_rsp[] = { 0x02, 0x7d };
288 unsigned char conf_req[] = { 0x03, 0xfc, 0x01 };
289 const unsigned char conf_rsp[] = { 0x04, 0x7b };
290 const unsigned char wakeup_req[] = { 0x05, 0xfa };
291 const unsigned char woken_req[] = { 0x06, 0xf9 };
292 const unsigned char sleep_req[] = { 0x07, 0x78 };
293 const unsigned char *hdr = h5->rx_skb->data;
294 const unsigned char *data = &h5->rx_skb->data[4];
295
296 BT_DBG("%s", hu->hdev->name);
297
298 if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT)
299 return;
300
301 if (H5_HDR_LEN(hdr) < 2)
302 return;
303
304 conf_req[2] = h5_cfg_field(h5);
305
306 if (memcmp(data, sync_req, 2) == 0) {
307 if (h5->state == H5_ACTIVE)
308 h5_peer_reset(hu);
309 h5_link_control(hu, sync_rsp, 2);
310 } else if (memcmp(data, sync_rsp, 2) == 0) {
311 if (h5->state == H5_ACTIVE)
312 h5_peer_reset(hu);
313 h5->state = H5_INITIALIZED;
314 h5_link_control(hu, conf_req, 3);
315 } else if (memcmp(data, conf_req, 2) == 0) {
316 h5_link_control(hu, conf_rsp, 2);
317 h5_link_control(hu, conf_req, 3);
318 } else if (memcmp(data, conf_rsp, 2) == 0) {
319 if (H5_HDR_LEN(hdr) > 2)
320 h5->tx_win = (data[2] & 7);
321 BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win);
322 h5->state = H5_ACTIVE;
323 hci_uart_init_ready(hu);
324 return;
325 } else if (memcmp(data, sleep_req, 2) == 0) {
326 BT_DBG("Peer went to sleep");
327 h5->sleep = H5_SLEEPING;
328 return;
329 } else if (memcmp(data, woken_req, 2) == 0) {
330 BT_DBG("Peer woke up");
331 h5->sleep = H5_AWAKE;
332 } else if (memcmp(data, wakeup_req, 2) == 0) {
333 BT_DBG("Peer requested wakeup");
334 h5_link_control(hu, woken_req, 2);
335 h5->sleep = H5_AWAKE;
336 } else {
337 BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]);
338 return;
339 }
340
341 hci_uart_tx_wakeup(hu);
342}
343
344static void h5_complete_rx_pkt(struct hci_uart *hu)
345{
346 struct h5 *h5 = hu->priv;
347 const unsigned char *hdr = h5->rx_skb->data;
348
349 if (H5_HDR_RELIABLE(hdr)) {
350 h5->tx_ack = (h5->tx_ack + 1) % 8;
351 set_bit(H5_TX_ACK_REQ, &h5->flags);
352 hci_uart_tx_wakeup(hu);
353 }
354
355 h5->rx_ack = H5_HDR_ACK(hdr);
356
357 h5_pkt_cull(h5);
358
359 switch (H5_HDR_PKT_TYPE(hdr)) {
360 case HCI_EVENT_PKT:
361 case HCI_ACLDATA_PKT:
362 case HCI_SCODATA_PKT:
363 bt_cb(h5->rx_skb)->pkt_type = H5_HDR_PKT_TYPE(hdr);
364
365
366 skb_pull(h5->rx_skb, 4);
367
368 hci_recv_frame(hu->hdev, h5->rx_skb);
369 h5->rx_skb = NULL;
370
371 break;
372
373 default:
374 h5_handle_internal_rx(hu);
375 break;
376 }
377
378 h5_reset_rx(h5);
379}
380
381static int h5_rx_crc(struct hci_uart *hu, unsigned char c)
382{
383 h5_complete_rx_pkt(hu);
384
385 return 0;
386}
387
388static int h5_rx_payload(struct hci_uart *hu, unsigned char c)
389{
390 struct h5 *h5 = hu->priv;
391 const unsigned char *hdr = h5->rx_skb->data;
392
393 if (H5_HDR_CRC(hdr)) {
394 h5->rx_func = h5_rx_crc;
395 h5->rx_pending = 2;
396 } else {
397 h5_complete_rx_pkt(hu);
398 }
399
400 return 0;
401}
402
403static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c)
404{
405 struct h5 *h5 = hu->priv;
406 const unsigned char *hdr = h5->rx_skb->data;
407
408 BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u",
409 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
410 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
411 H5_HDR_LEN(hdr));
412
413 if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) {
414 BT_ERR("Invalid header checksum");
415 h5_reset_rx(h5);
416 return 0;
417 }
418
419 if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) {
420 BT_ERR("Out-of-order packet arrived (%u != %u)",
421 H5_HDR_SEQ(hdr), h5->tx_ack);
422 h5_reset_rx(h5);
423 return 0;
424 }
425
426 if (h5->state != H5_ACTIVE &&
427 H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) {
428 BT_ERR("Non-link packet received in non-active state");
429 h5_reset_rx(h5);
430 return 0;
431 }
432
433 h5->rx_func = h5_rx_payload;
434 h5->rx_pending = H5_HDR_LEN(hdr);
435
436 return 0;
437}
438
439static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c)
440{
441 struct h5 *h5 = hu->priv;
442
443 if (c == SLIP_DELIMITER)
444 return 1;
445
446 h5->rx_func = h5_rx_3wire_hdr;
447 h5->rx_pending = 4;
448
449 h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC);
450 if (!h5->rx_skb) {
451 BT_ERR("Can't allocate mem for new packet");
452 h5_reset_rx(h5);
453 return -ENOMEM;
454 }
455
456 h5->rx_skb->dev = (void *) hu->hdev;
457
458 return 0;
459}
460
461static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c)
462{
463 struct h5 *h5 = hu->priv;
464
465 if (c == SLIP_DELIMITER)
466 h5->rx_func = h5_rx_pkt_start;
467
468 return 1;
469}
470
471static void h5_unslip_one_byte(struct h5 *h5, unsigned char c)
472{
473 const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC;
474 const u8 *byte = &c;
475
476 if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) {
477 set_bit(H5_RX_ESC, &h5->flags);
478 return;
479 }
480
481 if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) {
482 switch (c) {
483 case SLIP_ESC_DELIM:
484 byte = &delim;
485 break;
486 case SLIP_ESC_ESC:
487 byte = &esc;
488 break;
489 default:
490 BT_ERR("Invalid esc byte 0x%02hhx", c);
491 h5_reset_rx(h5);
492 return;
493 }
494 }
495
496 memcpy(skb_put(h5->rx_skb, 1), byte, 1);
497 h5->rx_pending--;
498
499 BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending);
500}
501
502static void h5_reset_rx(struct h5 *h5)
503{
504 if (h5->rx_skb) {
505 kfree_skb(h5->rx_skb);
506 h5->rx_skb = NULL;
507 }
508
509 h5->rx_func = h5_rx_delimiter;
510 h5->rx_pending = 0;
511 clear_bit(H5_RX_ESC, &h5->flags);
512}
513
514static int h5_recv(struct hci_uart *hu, const void *data, int count)
515{
516 struct h5 *h5 = hu->priv;
517 const unsigned char *ptr = data;
518
519 BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending,
520 count);
521
522 while (count > 0) {
523 int processed;
524
525 if (h5->rx_pending > 0) {
526 if (*ptr == SLIP_DELIMITER) {
527 BT_ERR("Too short H5 packet");
528 h5_reset_rx(h5);
529 continue;
530 }
531
532 h5_unslip_one_byte(h5, *ptr);
533
534 ptr++; count--;
535 continue;
536 }
537
538 processed = h5->rx_func(hu, *ptr);
539 if (processed < 0)
540 return processed;
541
542 ptr += processed;
543 count -= processed;
544 }
545
546 return 0;
547}
548
549static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
550{
551 struct h5 *h5 = hu->priv;
552
553 if (skb->len > 0xfff) {
554 BT_ERR("Packet too long (%u bytes)", skb->len);
555 kfree_skb(skb);
556 return 0;
557 }
558
559 if (h5->state != H5_ACTIVE) {
560 BT_ERR("Ignoring HCI data in non-active state");
561 kfree_skb(skb);
562 return 0;
563 }
564
565 switch (bt_cb(skb)->pkt_type) {
566 case HCI_ACLDATA_PKT:
567 case HCI_COMMAND_PKT:
568 skb_queue_tail(&h5->rel, skb);
569 break;
570
571 case HCI_SCODATA_PKT:
572 skb_queue_tail(&h5->unrel, skb);
573 break;
574
575 default:
576 BT_ERR("Unknown packet type %u", bt_cb(skb)->pkt_type);
577 kfree_skb(skb);
578 break;
579 }
580
581 return 0;
582}
583
584static void h5_slip_delim(struct sk_buff *skb)
585{
586 const char delim = SLIP_DELIMITER;
587
588 memcpy(skb_put(skb, 1), &delim, 1);
589}
590
591static void h5_slip_one_byte(struct sk_buff *skb, u8 c)
592{
593 const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM };
594 const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC };
595
596 switch (c) {
597 case SLIP_DELIMITER:
598 memcpy(skb_put(skb, 2), &esc_delim, 2);
599 break;
600 case SLIP_ESC:
601 memcpy(skb_put(skb, 2), &esc_esc, 2);
602 break;
603 default:
604 memcpy(skb_put(skb, 1), &c, 1);
605 }
606}
607
608static bool valid_packet_type(u8 type)
609{
610 switch (type) {
611 case HCI_ACLDATA_PKT:
612 case HCI_COMMAND_PKT:
613 case HCI_SCODATA_PKT:
614 case HCI_3WIRE_LINK_PKT:
615 case HCI_3WIRE_ACK_PKT:
616 return true;
617 default:
618 return false;
619 }
620}
621
622static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type,
623 const u8 *data, size_t len)
624{
625 struct h5 *h5 = hu->priv;
626 struct sk_buff *nskb;
627 u8 hdr[4];
628 int i;
629
630 if (!valid_packet_type(pkt_type)) {
631 BT_ERR("Unknown packet type %u", pkt_type);
632 return NULL;
633 }
634
635
636
637
638
639
640
641 nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
642 if (!nskb)
643 return NULL;
644
645 bt_cb(nskb)->pkt_type = pkt_type;
646
647 h5_slip_delim(nskb);
648
649 hdr[0] = h5->tx_ack << 3;
650 clear_bit(H5_TX_ACK_REQ, &h5->flags);
651
652
653 if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) {
654 hdr[0] |= 1 << 7;
655 hdr[0] |= h5->tx_seq;
656 h5->tx_seq = (h5->tx_seq + 1) % 8;
657 }
658
659 hdr[1] = pkt_type | ((len & 0x0f) << 4);
660 hdr[2] = len >> 4;
661 hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff);
662
663 BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u",
664 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr),
665 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr),
666 H5_HDR_LEN(hdr));
667
668 for (i = 0; i < 4; i++)
669 h5_slip_one_byte(nskb, hdr[i]);
670
671 for (i = 0; i < len; i++)
672 h5_slip_one_byte(nskb, data[i]);
673
674 h5_slip_delim(nskb);
675
676 return nskb;
677}
678
679static struct sk_buff *h5_dequeue(struct hci_uart *hu)
680{
681 struct h5 *h5 = hu->priv;
682 unsigned long flags;
683 struct sk_buff *skb, *nskb;
684
685 if (h5->sleep != H5_AWAKE) {
686 const unsigned char wakeup_req[] = { 0x05, 0xfa };
687
688 if (h5->sleep == H5_WAKING_UP)
689 return NULL;
690
691 h5->sleep = H5_WAKING_UP;
692 BT_DBG("Sending wakeup request");
693
694 mod_timer(&h5->timer, jiffies + HZ / 100);
695 return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2);
696 }
697
698 skb = skb_dequeue(&h5->unrel);
699 if (skb != NULL) {
700 nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
701 skb->data, skb->len);
702 if (nskb) {
703 kfree_skb(skb);
704 return nskb;
705 }
706
707 skb_queue_head(&h5->unrel, skb);
708 BT_ERR("Could not dequeue pkt because alloc_skb failed");
709 }
710
711 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING);
712
713 if (h5->unack.qlen >= h5->tx_win)
714 goto unlock;
715
716 skb = skb_dequeue(&h5->rel);
717 if (skb != NULL) {
718 nskb = h5_prepare_pkt(hu, bt_cb(skb)->pkt_type,
719 skb->data, skb->len);
720 if (nskb) {
721 __skb_queue_tail(&h5->unack, skb);
722 mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT);
723 spin_unlock_irqrestore(&h5->unack.lock, flags);
724 return nskb;
725 }
726
727 skb_queue_head(&h5->rel, skb);
728 BT_ERR("Could not dequeue pkt because alloc_skb failed");
729 }
730
731unlock:
732 spin_unlock_irqrestore(&h5->unack.lock, flags);
733
734 if (test_bit(H5_TX_ACK_REQ, &h5->flags))
735 return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0);
736
737 return NULL;
738}
739
740static int h5_flush(struct hci_uart *hu)
741{
742 BT_DBG("hu %p", hu);
743 return 0;
744}
745
746static const struct hci_uart_proto h5p = {
747 .id = HCI_UART_3WIRE,
748 .name = "Three-wire (H5)",
749 .open = h5_open,
750 .close = h5_close,
751 .recv = h5_recv,
752 .enqueue = h5_enqueue,
753 .dequeue = h5_dequeue,
754 .flush = h5_flush,
755};
756
757int __init h5_init(void)
758{
759 return hci_uart_register_proto(&h5p);
760}
761
762int __exit h5_deinit(void)
763{
764 return hci_uart_unregister_proto(&h5p);
765}
766
