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 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 /* Send initial sync request */ 199 h5_link_control(hu, sync, sizeof(sync)); 200 mod_timer(&h5->timer, jiffies + H5_SYNC_TIMEOUT); 201 202 return 0; 203 } 204 205 static 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 } 219 220 static 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); 257 258 unlock: 259 spin_unlock_irqrestore(&h5->unack.lock, flags); 260 } 261 262 static 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 } 318 319 static 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 /* Remove Three-wire header */ 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 } 355 356 static 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 } 365 366 static 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 } 381 382 static 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 } 416 417 static 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 } 438 439 static 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 } 448 449 static 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 } 479 480 static 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 } 491 492 static 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 } 526 527 static 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 } 561 562 static 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 } 568 569 static 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 } 585 586 static 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 } 599 600 static 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 * Max len of packet: (original len + 4 (H5 hdr) + 2 (crc)) * 2 615 * (because bytes 0xc0 and 0xdb are escaped, worst case is when 616 * the packet is all made of 0xc0 and 0xdb) + 2 (0xc0 617 * delimiters at start and end). 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 /* Reliable packet? */ 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 } 656 657 static 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 } 706 707 unlock: 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 } 715 716 static int h5_flush(struct hci_uart *hu) 717 { 718 BT_DBG("hu %p", hu); 719 return 0; 720 } 721 722 static 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 }; 731 732 int __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 } 743 744 int __exit h5_deinit(void) 745 { 746 return hci_uart_unregister_proto(&h5p); 747 } 748