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) & 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 /* 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 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 } 116 117 static u8 h5_cfg_field(struct h5 *h5) 118 { 119 u8 field = 0; 120 121 /* Sliding window size (first 3 bits) */ 122 field |= (h5->tx_win & 7); 123 124 return field; 125 } 126 127 static 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); 166 167 wakeup: 168 hci_uart_tx_wakeup(hu); 169 } 170 171 static 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 /* Send reset request to upper stack */ 189 hci_reset_dev(hu->hdev); 190 } 191 192 static 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 /* Send initial sync request */ 220 h5_link_control(hu, sync, sizeof(sync)); 221 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT); 222 223 return 0; 224 } 225 226 static 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 } 240 241 static 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); 278 279 unlock: 280 spin_unlock_irqrestore(&h5->unack.lock, flags); 281 } 282 283 static 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 } 343 344 static 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 /* Remove Three-wire header */ 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 } 380 381 static int h5_rx_crc(struct hci_uart *hu, unsigned char c) 382 { 383 h5_complete_rx_pkt(hu); 384 385 return 0; 386 } 387 388 static 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 } 402 403 static 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 } 438 439 static 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 } 460 461 static 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 } 470 471 static 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 } 501 502 static 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 } 513 514 static 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 } 548 549 static 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 } 583 584 static 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 } 590 591 static 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 } 607 608 static 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 } 621 622 static 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 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2 637 * (because bytes 0xc0 and 0xdb are escaped, worst case is when 638 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0 639 * delimiters at start and end). 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 /* Reliable packet? */ 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 } 678 679 static 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 } 730 731 unlock: 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 } 739 740 static int h5_flush(struct hci_uart *hu) 741 { 742 BT_DBG("hu %p", hu); 743 return 0; 744 } 745 746 static 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 }; 756 757 int __init h5_init(void) 758 { 759 return hci_uart_register_proto(&h5p); 760 } 761 762 int __exit h5_deinit(void) 763 { 764 return hci_uart_unregister_proto(&h5p); 765 } 766