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 init_timer(&h5->timer); 208 h5->timer.function = h5_timed_event; 209 h5->timer.data = (unsigned long)hu; 210 211 h5->tx_win = H5_TX_WIN_MAX; 212 213 set_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags); 214 215 /* Send initial sync request */ 216 h5_link_control(hu, sync, sizeof(sync)); 217 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT); 218 219 return 0; 220 } 221 222 static int h5_close(struct hci_uart *hu) 223 { 224 struct h5 *h5 = hu->priv; 225 226 del_timer_sync(&h5->timer); 227 228 skb_queue_purge(&h5->unack); 229 skb_queue_purge(&h5->rel); 230 skb_queue_purge(&h5->unrel); 231 232 kfree(h5); 233 234 return 0; 235 } 236 237 static void h5_pkt_cull(struct h5 *h5) 238 { 239 struct sk_buff *skb, *tmp; 240 unsigned long flags; 241 int i, to_remove; 242 u8 seq; 243 244 spin_lock_irqsave(&h5->unack.lock, flags); 245 246 to_remove = skb_queue_len(&h5->unack); 247 if (to_remove == 0) 248 goto unlock; 249 250 seq = h5->tx_seq; 251 252 while (to_remove > 0) { 253 if (h5->rx_ack == seq) 254 break; 255 256 to_remove--; 257 seq = (seq - 1) & 0x07; 258 } 259 260 if (seq != h5->rx_ack) 261 BT_ERR("Controller acked invalid packet"); 262 263 i = 0; 264 skb_queue_walk_safe(&h5->unack, skb, tmp) { 265 if (i++ >= to_remove) 266 break; 267 268 __skb_unlink(skb, &h5->unack); 269 kfree_skb(skb); 270 } 271 272 if (skb_queue_empty(&h5->unack)) 273 del_timer(&h5->timer); 274 275 unlock: 276 spin_unlock_irqrestore(&h5->unack.lock, flags); 277 } 278 279 static void h5_handle_internal_rx(struct hci_uart *hu) 280 { 281 struct h5 *h5 = hu->priv; 282 const unsigned char sync_req[] = { 0x01, 0x7e }; 283 const unsigned char sync_rsp[] = { 0x02, 0x7d }; 284 unsigned char conf_req[3] = { 0x03, 0xfc }; 285 const unsigned char conf_rsp[] = { 0x04, 0x7b }; 286 const unsigned char wakeup_req[] = { 0x05, 0xfa }; 287 const unsigned char woken_req[] = { 0x06, 0xf9 }; 288 const unsigned char sleep_req[] = { 0x07, 0x78 }; 289 const unsigned char *hdr = h5->rx_skb->data; 290 const unsigned char *data = &h5->rx_skb->data[4]; 291 292 BT_DBG("%s", hu->hdev->name); 293 294 if (H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) 295 return; 296 297 if (H5_HDR_LEN(hdr) < 2) 298 return; 299 300 conf_req[2] = h5_cfg_field(h5); 301 302 if (memcmp(data, sync_req, 2) == 0) { 303 if (h5->state == H5_ACTIVE) 304 h5_peer_reset(hu); 305 h5_link_control(hu, sync_rsp, 2); 306 } else if (memcmp(data, sync_rsp, 2) == 0) { 307 if (h5->state == H5_ACTIVE) 308 h5_peer_reset(hu); 309 h5->state = H5_INITIALIZED; 310 h5_link_control(hu, conf_req, 3); 311 } else if (memcmp(data, conf_req, 2) == 0) { 312 h5_link_control(hu, conf_rsp, 2); 313 h5_link_control(hu, conf_req, 3); 314 } else if (memcmp(data, conf_rsp, 2) == 0) { 315 if (H5_HDR_LEN(hdr) > 2) 316 h5->tx_win = (data[2] & 0x07); 317 BT_DBG("Three-wire init complete. tx_win %u", h5->tx_win); 318 h5->state = H5_ACTIVE; 319 hci_uart_init_ready(hu); 320 return; 321 } else if (memcmp(data, sleep_req, 2) == 0) { 322 BT_DBG("Peer went to sleep"); 323 h5->sleep = H5_SLEEPING; 324 return; 325 } else if (memcmp(data, woken_req, 2) == 0) { 326 BT_DBG("Peer woke up"); 327 h5->sleep = H5_AWAKE; 328 } else if (memcmp(data, wakeup_req, 2) == 0) { 329 BT_DBG("Peer requested wakeup"); 330 h5_link_control(hu, woken_req, 2); 331 h5->sleep = H5_AWAKE; 332 } else { 333 BT_DBG("Link Control: 0x%02hhx 0x%02hhx", data[0], data[1]); 334 return; 335 } 336 337 hci_uart_tx_wakeup(hu); 338 } 339 340 static void h5_complete_rx_pkt(struct hci_uart *hu) 341 { 342 struct h5 *h5 = hu->priv; 343 const unsigned char *hdr = h5->rx_skb->data; 344 345 if (H5_HDR_RELIABLE(hdr)) { 346 h5->tx_ack = (h5->tx_ack + 1) % 8; 347 set_bit(H5_TX_ACK_REQ, &h5->flags); 348 hci_uart_tx_wakeup(hu); 349 } 350 351 h5->rx_ack = H5_HDR_ACK(hdr); 352 353 h5_pkt_cull(h5); 354 355 switch (H5_HDR_PKT_TYPE(hdr)) { 356 case HCI_EVENT_PKT: 357 case HCI_ACLDATA_PKT: 358 case HCI_SCODATA_PKT: 359 hci_skb_pkt_type(h5->rx_skb) = H5_HDR_PKT_TYPE(hdr); 360 361 /* Remove Three-wire header */ 362 skb_pull(h5->rx_skb, 4); 363 364 hci_recv_frame(hu->hdev, h5->rx_skb); 365 h5->rx_skb = NULL; 366 367 break; 368 369 default: 370 h5_handle_internal_rx(hu); 371 break; 372 } 373 374 h5_reset_rx(h5); 375 } 376 377 static int h5_rx_crc(struct hci_uart *hu, unsigned char c) 378 { 379 h5_complete_rx_pkt(hu); 380 381 return 0; 382 } 383 384 static int h5_rx_payload(struct hci_uart *hu, unsigned char c) 385 { 386 struct h5 *h5 = hu->priv; 387 const unsigned char *hdr = h5->rx_skb->data; 388 389 if (H5_HDR_CRC(hdr)) { 390 h5->rx_func = h5_rx_crc; 391 h5->rx_pending = 2; 392 } else { 393 h5_complete_rx_pkt(hu); 394 } 395 396 return 0; 397 } 398 399 static int h5_rx_3wire_hdr(struct hci_uart *hu, unsigned char c) 400 { 401 struct h5 *h5 = hu->priv; 402 const unsigned char *hdr = h5->rx_skb->data; 403 404 BT_DBG("%s rx: seq %u ack %u crc %u rel %u type %u len %u", 405 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr), 406 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr), 407 H5_HDR_LEN(hdr)); 408 409 if (((hdr[0] + hdr[1] + hdr[2] + hdr[3]) & 0xff) != 0xff) { 410 BT_ERR("Invalid header checksum"); 411 h5_reset_rx(h5); 412 return 0; 413 } 414 415 if (H5_HDR_RELIABLE(hdr) && H5_HDR_SEQ(hdr) != h5->tx_ack) { 416 BT_ERR("Out-of-order packet arrived (%u != %u)", 417 H5_HDR_SEQ(hdr), h5->tx_ack); 418 h5_reset_rx(h5); 419 return 0; 420 } 421 422 if (h5->state != H5_ACTIVE && 423 H5_HDR_PKT_TYPE(hdr) != HCI_3WIRE_LINK_PKT) { 424 BT_ERR("Non-link packet received in non-active state"); 425 h5_reset_rx(h5); 426 return 0; 427 } 428 429 h5->rx_func = h5_rx_payload; 430 h5->rx_pending = H5_HDR_LEN(hdr); 431 432 return 0; 433 } 434 435 static int h5_rx_pkt_start(struct hci_uart *hu, unsigned char c) 436 { 437 struct h5 *h5 = hu->priv; 438 439 if (c == SLIP_DELIMITER) 440 return 1; 441 442 h5->rx_func = h5_rx_3wire_hdr; 443 h5->rx_pending = 4; 444 445 h5->rx_skb = bt_skb_alloc(H5_MAX_LEN, GFP_ATOMIC); 446 if (!h5->rx_skb) { 447 BT_ERR("Can't allocate mem for new packet"); 448 h5_reset_rx(h5); 449 return -ENOMEM; 450 } 451 452 h5->rx_skb->dev = (void *)hu->hdev; 453 454 return 0; 455 } 456 457 static int h5_rx_delimiter(struct hci_uart *hu, unsigned char c) 458 { 459 struct h5 *h5 = hu->priv; 460 461 if (c == SLIP_DELIMITER) 462 h5->rx_func = h5_rx_pkt_start; 463 464 return 1; 465 } 466 467 static void h5_unslip_one_byte(struct h5 *h5, unsigned char c) 468 { 469 const u8 delim = SLIP_DELIMITER, esc = SLIP_ESC; 470 const u8 *byte = &c; 471 472 if (!test_bit(H5_RX_ESC, &h5->flags) && c == SLIP_ESC) { 473 set_bit(H5_RX_ESC, &h5->flags); 474 return; 475 } 476 477 if (test_and_clear_bit(H5_RX_ESC, &h5->flags)) { 478 switch (c) { 479 case SLIP_ESC_DELIM: 480 byte = &delim; 481 break; 482 case SLIP_ESC_ESC: 483 byte = &esc; 484 break; 485 default: 486 BT_ERR("Invalid esc byte 0x%02hhx", c); 487 h5_reset_rx(h5); 488 return; 489 } 490 } 491 492 memcpy(skb_put(h5->rx_skb, 1), byte, 1); 493 h5->rx_pending--; 494 495 BT_DBG("unsliped 0x%02hhx, rx_pending %zu", *byte, h5->rx_pending); 496 } 497 498 static void h5_reset_rx(struct h5 *h5) 499 { 500 if (h5->rx_skb) { 501 kfree_skb(h5->rx_skb); 502 h5->rx_skb = NULL; 503 } 504 505 h5->rx_func = h5_rx_delimiter; 506 h5->rx_pending = 0; 507 clear_bit(H5_RX_ESC, &h5->flags); 508 } 509 510 static int h5_recv(struct hci_uart *hu, const void *data, int count) 511 { 512 struct h5 *h5 = hu->priv; 513 const unsigned char *ptr = data; 514 515 BT_DBG("%s pending %zu count %d", hu->hdev->name, h5->rx_pending, 516 count); 517 518 while (count > 0) { 519 int processed; 520 521 if (h5->rx_pending > 0) { 522 if (*ptr == SLIP_DELIMITER) { 523 BT_ERR("Too short H5 packet"); 524 h5_reset_rx(h5); 525 continue; 526 } 527 528 h5_unslip_one_byte(h5, *ptr); 529 530 ptr++; count--; 531 continue; 532 } 533 534 processed = h5->rx_func(hu, *ptr); 535 if (processed < 0) 536 return processed; 537 538 ptr += processed; 539 count -= processed; 540 } 541 542 return 0; 543 } 544 545 static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb) 546 { 547 struct h5 *h5 = hu->priv; 548 549 if (skb->len > 0xfff) { 550 BT_ERR("Packet too long (%u bytes)", skb->len); 551 kfree_skb(skb); 552 return 0; 553 } 554 555 if (h5->state != H5_ACTIVE) { 556 BT_ERR("Ignoring HCI data in non-active state"); 557 kfree_skb(skb); 558 return 0; 559 } 560 561 switch (hci_skb_pkt_type(skb)) { 562 case HCI_ACLDATA_PKT: 563 case HCI_COMMAND_PKT: 564 skb_queue_tail(&h5->rel, skb); 565 break; 566 567 case HCI_SCODATA_PKT: 568 skb_queue_tail(&h5->unrel, skb); 569 break; 570 571 default: 572 BT_ERR("Unknown packet type %u", hci_skb_pkt_type(skb)); 573 kfree_skb(skb); 574 break; 575 } 576 577 return 0; 578 } 579 580 static void h5_slip_delim(struct sk_buff *skb) 581 { 582 const char delim = SLIP_DELIMITER; 583 584 memcpy(skb_put(skb, 1), &delim, 1); 585 } 586 587 static void h5_slip_one_byte(struct sk_buff *skb, u8 c) 588 { 589 const char esc_delim[2] = { SLIP_ESC, SLIP_ESC_DELIM }; 590 const char esc_esc[2] = { SLIP_ESC, SLIP_ESC_ESC }; 591 592 switch (c) { 593 case SLIP_DELIMITER: 594 memcpy(skb_put(skb, 2), &esc_delim, 2); 595 break; 596 case SLIP_ESC: 597 memcpy(skb_put(skb, 2), &esc_esc, 2); 598 break; 599 default: 600 memcpy(skb_put(skb, 1), &c, 1); 601 } 602 } 603 604 static bool valid_packet_type(u8 type) 605 { 606 switch (type) { 607 case HCI_ACLDATA_PKT: 608 case HCI_COMMAND_PKT: 609 case HCI_SCODATA_PKT: 610 case HCI_3WIRE_LINK_PKT: 611 case HCI_3WIRE_ACK_PKT: 612 return true; 613 default: 614 return false; 615 } 616 } 617 618 static struct sk_buff *h5_prepare_pkt(struct hci_uart *hu, u8 pkt_type, 619 const u8 *data, size_t len) 620 { 621 struct h5 *h5 = hu->priv; 622 struct sk_buff *nskb; 623 u8 hdr[4]; 624 int i; 625 626 if (!valid_packet_type(pkt_type)) { 627 BT_ERR("Unknown packet type %u", pkt_type); 628 return NULL; 629 } 630 631 /* 632 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2 633 * (because bytes 0xc0 and 0xdb are escaped, worst case is when 634 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0 635 * delimiters at start and end). 636 */ 637 nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC); 638 if (!nskb) 639 return NULL; 640 641 hci_skb_pkt_type(nskb) = pkt_type; 642 643 h5_slip_delim(nskb); 644 645 hdr[0] = h5->tx_ack << 3; 646 clear_bit(H5_TX_ACK_REQ, &h5->flags); 647 648 /* Reliable packet? */ 649 if (pkt_type == HCI_ACLDATA_PKT || pkt_type == HCI_COMMAND_PKT) { 650 hdr[0] |= 1 << 7; 651 hdr[0] |= h5->tx_seq; 652 h5->tx_seq = (h5->tx_seq + 1) % 8; 653 } 654 655 hdr[1] = pkt_type | ((len & 0x0f) << 4); 656 hdr[2] = len >> 4; 657 hdr[3] = ~((hdr[0] + hdr[1] + hdr[2]) & 0xff); 658 659 BT_DBG("%s tx: seq %u ack %u crc %u rel %u type %u len %u", 660 hu->hdev->name, H5_HDR_SEQ(hdr), H5_HDR_ACK(hdr), 661 H5_HDR_CRC(hdr), H5_HDR_RELIABLE(hdr), H5_HDR_PKT_TYPE(hdr), 662 H5_HDR_LEN(hdr)); 663 664 for (i = 0; i < 4; i++) 665 h5_slip_one_byte(nskb, hdr[i]); 666 667 for (i = 0; i < len; i++) 668 h5_slip_one_byte(nskb, data[i]); 669 670 h5_slip_delim(nskb); 671 672 return nskb; 673 } 674 675 static struct sk_buff *h5_dequeue(struct hci_uart *hu) 676 { 677 struct h5 *h5 = hu->priv; 678 unsigned long flags; 679 struct sk_buff *skb, *nskb; 680 681 if (h5->sleep != H5_AWAKE) { 682 const unsigned char wakeup_req[] = { 0x05, 0xfa }; 683 684 if (h5->sleep == H5_WAKING_UP) 685 return NULL; 686 687 h5->sleep = H5_WAKING_UP; 688 BT_DBG("Sending wakeup request"); 689 690 mod_timer(&h5->timer, jiffies + HZ / 100); 691 return h5_prepare_pkt(hu, HCI_3WIRE_LINK_PKT, wakeup_req, 2); 692 } 693 694 skb = skb_dequeue(&h5->unrel); 695 if (skb) { 696 nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb), 697 skb->data, skb->len); 698 if (nskb) { 699 kfree_skb(skb); 700 return nskb; 701 } 702 703 skb_queue_head(&h5->unrel, skb); 704 BT_ERR("Could not dequeue pkt because alloc_skb failed"); 705 } 706 707 spin_lock_irqsave_nested(&h5->unack.lock, flags, SINGLE_DEPTH_NESTING); 708 709 if (h5->unack.qlen >= h5->tx_win) 710 goto unlock; 711 712 skb = skb_dequeue(&h5->rel); 713 if (skb) { 714 nskb = h5_prepare_pkt(hu, hci_skb_pkt_type(skb), 715 skb->data, skb->len); 716 if (nskb) { 717 __skb_queue_tail(&h5->unack, skb); 718 mod_timer(&h5->timer, jiffies + H5_ACK_TIMEOUT); 719 spin_unlock_irqrestore(&h5->unack.lock, flags); 720 return nskb; 721 } 722 723 skb_queue_head(&h5->rel, skb); 724 BT_ERR("Could not dequeue pkt because alloc_skb failed"); 725 } 726 727 unlock: 728 spin_unlock_irqrestore(&h5->unack.lock, flags); 729 730 if (test_bit(H5_TX_ACK_REQ, &h5->flags)) 731 return h5_prepare_pkt(hu, HCI_3WIRE_ACK_PKT, NULL, 0); 732 733 return NULL; 734 } 735 736 static int h5_flush(struct hci_uart *hu) 737 { 738 BT_DBG("hu %p", hu); 739 return 0; 740 } 741 742 static const struct hci_uart_proto h5p = { 743 .id = HCI_UART_3WIRE, 744 .name = "Three-wire (H5)", 745 .open = h5_open, 746 .close = h5_close, 747 .recv = h5_recv, 748 .enqueue = h5_enqueue, 749 .dequeue = h5_dequeue, 750 .flush = h5_flush, 751 }; 752 753 int __init h5_init(void) 754 { 755 return hci_uart_register_proto(&h5p); 756 } 757 758 int __exit h5_deinit(void) 759 { 760 return hci_uart_unregister_proto(&h5p); 761 } 762