drivers/bluetooth/hci_bcsp.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *
   4  *  Bluetooth HCI UART driver
   5  *
   6  *  Copyright (C) 2002-2003  Fabrizio Gennari <fabrizio.gennari@philips.com>
   7  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
   8  */
   9
  10 #include <linux/module.h>
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/types.h>
  15 #include <linux/fcntl.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/ptrace.h>
  18 #include <linux/poll.h>
  19
  20 #include <linux/slab.h>
  21 #include <linux/tty.h>
  22 #include <linux/errno.h>
  23 #include <linux/string.h>
  24 #include <linux/signal.h>
  25 #include <linux/ioctl.h>
  26 #include <linux/skbuff.h>
  27 #include <linux/bitrev.h>
  28 #include <asm/unaligned.h>
  29
  30 #include <net/bluetooth/bluetooth.h>
  31 #include <net/bluetooth/hci_core.h>
  32
  33 #include "hci_uart.h"
  34
  35 static bool txcrc = true;
  36 static bool hciextn = true;
  37
  38 #define BCSP_TXWINSIZE  4
  39
  40 #define BCSP_ACK_PKT    0x05
  41 #define BCSP_LE_PKT     0x06
  42
  43 struct bcsp_struct {
  44         struct sk_buff_head unack;      /* Unack'ed packets queue */
  45         struct sk_buff_head rel;        /* Reliable packets queue */
  46         struct sk_buff_head unrel;      /* Unreliable packets queue */
  47
  48         unsigned long rx_count;
  49         struct  sk_buff *rx_skb;
  50         u8      rxseq_txack;            /* rxseq == txack. */
  51         u8      rxack;                  /* Last packet sent by us that the peer ack'ed */
  52         struct  timer_list tbcsp;
  53         struct  hci_uart *hu;
  54
  55         enum {
  56                 BCSP_W4_PKT_DELIMITER,
  57                 BCSP_W4_PKT_START,
  58                 BCSP_W4_BCSP_HDR,
  59                 BCSP_W4_DATA,
  60                 BCSP_W4_CRC
  61         } rx_state;
  62
  63         enum {
  64                 BCSP_ESCSTATE_NOESC,
  65                 BCSP_ESCSTATE_ESC
  66         } rx_esc_state;
  67
  68         u8      use_crc;
  69         u16     message_crc;
  70         u8      txack_req;              /* Do we need to send ack's to the peer? */
  71
  72         /* Reliable packet sequence number - used to assign seq to each rel pkt. */
  73         u8      msgq_txseq;
  74 };
  75
  76 /* ---- BCSP CRC calculation ---- */
  77
  78 /* Table for calculating CRC for polynomial 0x1021, LSB processed first,
  79  * initial value 0xffff, bits shifted in reverse order.
  80  */
  81
  82 static const u16 crc_table[] = {
  83         0x0000, 0x1081, 0x2102, 0x3183,
  84         0x4204, 0x5285, 0x6306, 0x7387,
  85         0x8408, 0x9489, 0xa50a, 0xb58b,
  86         0xc60c, 0xd68d, 0xe70e, 0xf78f
  87 };
  88
  89 /* Initialise the crc calculator */
  90 #define BCSP_CRC_INIT(x) x = 0xffff
  91
  92 /* Update crc with next data byte
  93  *
  94  * Implementation note
  95  *     The data byte is treated as two nibbles.  The crc is generated
  96  *     in reverse, i.e., bits are fed into the register from the top.
  97  */
  98 static void bcsp_crc_update(u16 *crc, u8 d)
  99 {
 100         u16 reg = *crc;
 101
 102         reg = (reg >> 4) ^ crc_table[(reg ^ d) & 0x000f];
 103         reg = (reg >> 4) ^ crc_table[(reg ^ (d >> 4)) & 0x000f];
 104
 105         *crc = reg;
 106 }
 107
 108 /* ---- BCSP core ---- */
 109
 110 static void bcsp_slip_msgdelim(struct sk_buff *skb)
 111 {
 112         const char pkt_delim = 0xc0;
 113
 114         skb_put_data(skb, &pkt_delim, 1);
 115 }
 116
 117 static void bcsp_slip_one_byte(struct sk_buff *skb, u8 c)
 118 {
 119         const char esc_c0[2] = { 0xdb, 0xdc };
 120         const char esc_db[2] = { 0xdb, 0xdd };
 121
 122         switch (c) {
 123         case 0xc0:
 124                 skb_put_data(skb, &esc_c0, 2);
 125                 break;
 126         case 0xdb:
 127                 skb_put_data(skb, &esc_db, 2);
 128                 break;
 129         default:
 130                 skb_put_data(skb, &c, 1);
 131         }
 132 }
 133
 134 static int bcsp_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 135 {
 136         struct bcsp_struct *bcsp = hu->priv;
 137
 138         if (skb->len > 0xFFF) {
 139                 BT_ERR("Packet too long");
 140                 kfree_skb(skb);
 141                 return 0;
 142         }
 143
 144         switch (hci_skb_pkt_type(skb)) {
 145         case HCI_ACLDATA_PKT:
 146         case HCI_COMMAND_PKT:
 147                 skb_queue_tail(&bcsp->rel, skb);
 148                 break;
 149
 150         case HCI_SCODATA_PKT:
 151                 skb_queue_tail(&bcsp->unrel, skb);
 152                 break;
 153
 154         default:
 155                 BT_ERR("Unknown packet type");
 156                 kfree_skb(skb);
 157                 break;
 158         }
 159
 160         return 0;
 161 }
 162
 163 static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
 164                                         int len, int pkt_type)
 165 {
 166         struct sk_buff *nskb;
 167         u8 hdr[4], chan;
 168         u16 BCSP_CRC_INIT(bcsp_txmsg_crc);
 169         int rel, i;
 170
 171         switch (pkt_type) {
 172         case HCI_ACLDATA_PKT:
 173                 chan = 6;       /* BCSP ACL channel */
 174                 rel = 1;        /* reliable channel */
 175                 break;
 176         case HCI_COMMAND_PKT:
 177                 chan = 5;       /* BCSP cmd/evt channel */
 178                 rel = 1;        /* reliable channel */
 179                 break;
 180         case HCI_SCODATA_PKT:
 181                 chan = 7;       /* BCSP SCO channel */
 182                 rel = 0;        /* unreliable channel */
 183                 break;
 184         case BCSP_LE_PKT:
 185                 chan = 1;       /* BCSP LE channel */
 186                 rel = 0;        /* unreliable channel */
 187                 break;
 188         case BCSP_ACK_PKT:
 189                 chan = 0;       /* BCSP internal channel */
 190                 rel = 0;        /* unreliable channel */
 191                 break;
 192         default:
 193                 BT_ERR("Unknown packet type");
 194                 return NULL;
 195         }
 196
 197         if (hciextn && chan == 5) {
 198                 __le16 opcode = ((struct hci_command_hdr *)data)->opcode;
 199
 200                 /* Vendor specific commands */
 201                 if (hci_opcode_ogf(__le16_to_cpu(opcode)) == 0x3f) {
 202                         u8 desc = *(data + HCI_COMMAND_HDR_SIZE);
 203
 204                         if ((desc & 0xf0) == 0xc0) {
 205                                 data += HCI_COMMAND_HDR_SIZE + 1;
 206                                 len  -= HCI_COMMAND_HDR_SIZE + 1;
 207                                 chan = desc & 0x0f;
 208                         }
 209                 }
 210         }
 211
 212         /* Max len of packet: (original len +4(bcsp hdr) +2(crc))*2
 213          * (because bytes 0xc0 and 0xdb are escaped, worst case is
 214          * when the packet is all made of 0xc0 and 0xdb :) )
 215          * + 2 (0xc0 delimiters at start and end).
 216          */
 217
 218         nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
 219         if (!nskb)
 220                 return NULL;
 221
 222         hci_skb_pkt_type(nskb) = pkt_type;
 223
 224         bcsp_slip_msgdelim(nskb);
 225
 226         hdr[0] = bcsp->rxseq_txack << 3;
 227         bcsp->txack_req = 0;
 228         BT_DBG("We request packet no %u to card", bcsp->rxseq_txack);
 229
 230         if (rel) {
 231                 hdr[0] |= 0x80 + bcsp->msgq_txseq;
 232                 BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq);
 233                 bcsp->msgq_txseq = (bcsp->msgq_txseq + 1) & 0x07;
 234         }
 235
 236         if (bcsp->use_crc)
 237                 hdr[0] |= 0x40;
 238
 239         hdr[1] = ((len << 4) & 0xff) | chan;
 240         hdr[2] = len >> 4;
 241         hdr[3] = ~(hdr[0] + hdr[1] + hdr[2]);
 242
 243         /* Put BCSP header */
 244         for (i = 0; i < 4; i++) {
 245                 bcsp_slip_one_byte(nskb, hdr[i]);
 246
 247                 if (bcsp->use_crc)
 248                         bcsp_crc_update(&bcsp_txmsg_crc, hdr[i]);
 249         }
 250
 251         /* Put payload */
 252         for (i = 0; i < len; i++) {
 253                 bcsp_slip_one_byte(nskb, data[i]);
 254
 255                 if (bcsp->use_crc)
 256                         bcsp_crc_update(&bcsp_txmsg_crc, data[i]);
 257         }
 258
 259         /* Put CRC */
 260         if (bcsp->use_crc) {
 261                 bcsp_txmsg_crc = bitrev16(bcsp_txmsg_crc);
 262                 bcsp_slip_one_byte(nskb, (u8)((bcsp_txmsg_crc >> 8) & 0x00ff));
 263                 bcsp_slip_one_byte(nskb, (u8)(bcsp_txmsg_crc & 0x00ff));
 264         }
 265
 266         bcsp_slip_msgdelim(nskb);
 267         return nskb;
 268 }
 269
 270 /* This is a rewrite of pkt_avail in ABCSP */
 271 static struct sk_buff *bcsp_dequeue(struct hci_uart *hu)
 272 {
 273         struct bcsp_struct *bcsp = hu->priv;
 274         unsigned long flags;
 275         struct sk_buff *skb;
 276
 277         /* First of all, check for unreliable messages in the queue,
 278          * since they have priority
 279          */
 280
 281         skb = skb_dequeue(&bcsp->unrel);
 282         if (skb != NULL) {
 283                 struct sk_buff *nskb;
 284
 285                 nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len,
 286                                         hci_skb_pkt_type(skb));
 287                 if (nskb) {
 288                         kfree_skb(skb);
 289                         return nskb;
 290                 } else {
 291                         skb_queue_head(&bcsp->unrel, skb);
 292                         BT_ERR("Could not dequeue pkt because alloc_skb failed");
 293                 }
 294         }
 295
 296         /* Now, try to send a reliable pkt. We can only send a
 297          * reliable packet if the number of packets sent but not yet ack'ed
 298          * is < than the winsize
 299          */
 300
 301         spin_lock_irqsave_nested(&bcsp->unack.lock, flags, SINGLE_DEPTH_NESTING);
 302
 303         if (bcsp->unack.qlen < BCSP_TXWINSIZE) {
 304                 skb = skb_dequeue(&bcsp->rel);
 305                 if (skb != NULL) {
 306                         struct sk_buff *nskb;
 307
 308                         nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len,
 309                                                 hci_skb_pkt_type(skb));
 310                         if (nskb) {
 311                                 __skb_queue_tail(&bcsp->unack, skb);
 312                                 mod_timer(&bcsp->tbcsp, jiffies + HZ / 4);
 313                                 spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 314                                 return nskb;
 315                         } else {
 316                                 skb_queue_head(&bcsp->rel, skb);
 317                                 BT_ERR("Could not dequeue pkt because alloc_skb failed");
 318                         }
 319                 }
 320         }
 321
 322         spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 323
 324         /* We could not send a reliable packet, either because there are
 325          * none or because there are too many unack'ed pkts. Did we receive
 326          * any packets we have not acknowledged yet ?
 327          */
 328
 329         if (bcsp->txack_req) {
 330                 /* if so, craft an empty ACK pkt and send it on BCSP unreliable
 331                  * channel 0
 332                  */
 333                 struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, NULL, 0, BCSP_ACK_PKT);
 334                 return nskb;
 335         }
 336
 337         /* We have nothing to send */
 338         return NULL;
 339 }
 340
 341 static int bcsp_flush(struct hci_uart *hu)
 342 {
 343         BT_DBG("hu %p", hu);
 344         return 0;
 345 }
 346
 347 /* Remove ack'ed packets */
 348 static void bcsp_pkt_cull(struct bcsp_struct *bcsp)
 349 {
 350         struct sk_buff *skb, *tmp;
 351         unsigned long flags;
 352         int i, pkts_to_be_removed;
 353         u8 seqno;
 354
 355         spin_lock_irqsave(&bcsp->unack.lock, flags);
 356
 357         pkts_to_be_removed = skb_queue_len(&bcsp->unack);
 358         seqno = bcsp->msgq_txseq;
 359
 360         while (pkts_to_be_removed) {
 361                 if (bcsp->rxack == seqno)
 362                         break;
 363                 pkts_to_be_removed--;
 364                 seqno = (seqno - 1) & 0x07;
 365         }
 366
 367         if (bcsp->rxack != seqno)
 368                 BT_ERR("Peer acked invalid packet");
 369
 370         BT_DBG("Removing %u pkts out of %u, up to seqno %u",
 371                pkts_to_be_removed, skb_queue_len(&bcsp->unack),
 372                (seqno - 1) & 0x07);
 373
 374         i = 0;
 375         skb_queue_walk_safe(&bcsp->unack, skb, tmp) {
 376                 if (i >= pkts_to_be_removed)
 377                         break;
 378                 i++;
 379
 380                 __skb_unlink(skb, &bcsp->unack);
 381                 dev_kfree_skb_irq(skb);
 382         }
 383
 384         if (skb_queue_empty(&bcsp->unack))
 385                 del_timer(&bcsp->tbcsp);
 386
 387         spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 388
 389         if (i != pkts_to_be_removed)
 390                 BT_ERR("Removed only %u out of %u pkts", i, pkts_to_be_removed);
 391 }
 392
 393 /* Handle BCSP link-establishment packets. When we
 394  * detect a "sync" packet, symptom that the BT module has reset,
 395  * we do nothing :) (yet)
 396  */
 397 static void bcsp_handle_le_pkt(struct hci_uart *hu)
 398 {
 399         struct bcsp_struct *bcsp = hu->priv;
 400         u8 conf_pkt[4]     = { 0xad, 0xef, 0xac, 0xed };
 401         u8 conf_rsp_pkt[4] = { 0xde, 0xad, 0xd0, 0xd0 };
 402         u8 sync_pkt[4]     = { 0xda, 0xdc, 0xed, 0xed };
 403
 404         /* spot "conf" pkts and reply with a "conf rsp" pkt */
 405         if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
 406             !memcmp(&bcsp->rx_skb->data[4], conf_pkt, 4)) {
 407                 struct sk_buff *nskb = alloc_skb(4, GFP_ATOMIC);
 408
 409                 BT_DBG("Found a LE conf pkt");
 410                 if (!nskb)
 411                         return;
 412                 skb_put_data(nskb, conf_rsp_pkt, 4);
 413                 hci_skb_pkt_type(nskb) = BCSP_LE_PKT;
 414
 415                 skb_queue_head(&bcsp->unrel, nskb);
 416                 hci_uart_tx_wakeup(hu);
 417         }
 418         /* Spot "sync" pkts. If we find one...disaster! */
 419         else if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
 420                  !memcmp(&bcsp->rx_skb->data[4], sync_pkt, 4)) {
 421                 BT_ERR("Found a LE sync pkt, card has reset");
 422         }
 423 }
 424
 425 static inline void bcsp_unslip_one_byte(struct bcsp_struct *bcsp, unsigned char byte)
 426 {
 427         const u8 c0 = 0xc0, db = 0xdb;
 428
 429         switch (bcsp->rx_esc_state) {
 430         case BCSP_ESCSTATE_NOESC:
 431                 switch (byte) {
 432                 case 0xdb:
 433                         bcsp->rx_esc_state = BCSP_ESCSTATE_ESC;
 434                         break;
 435                 default:
 436                         skb_put_data(bcsp->rx_skb, &byte, 1);
 437                         if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
 438                             bcsp->rx_state != BCSP_W4_CRC)
 439                                 bcsp_crc_update(&bcsp->message_crc, byte);
 440                         bcsp->rx_count--;
 441                 }
 442                 break;
 443
 444         case BCSP_ESCSTATE_ESC:
 445                 switch (byte) {
 446                 case 0xdc:
 447                         skb_put_data(bcsp->rx_skb, &c0, 1);
 448                         if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
 449                             bcsp->rx_state != BCSP_W4_CRC)
 450                                 bcsp_crc_update(&bcsp->message_crc, 0xc0);
 451                         bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
 452                         bcsp->rx_count--;
 453                         break;
 454
 455                 case 0xdd:
 456                         skb_put_data(bcsp->rx_skb, &db, 1);
 457                         if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
 458                             bcsp->rx_state != BCSP_W4_CRC)
 459                                 bcsp_crc_update(&bcsp->message_crc, 0xdb);
 460                         bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
 461                         bcsp->rx_count--;
 462                         break;
 463
 464                 default:
 465                         BT_ERR("Invalid byte %02x after esc byte", byte);
 466                         kfree_skb(bcsp->rx_skb);
 467                         bcsp->rx_skb = NULL;
 468                         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 469                         bcsp->rx_count = 0;
 470                 }
 471         }
 472 }
 473
 474 static void bcsp_complete_rx_pkt(struct hci_uart *hu)
 475 {
 476         struct bcsp_struct *bcsp = hu->priv;
 477         int pass_up = 0;
 478
 479         if (bcsp->rx_skb->data[0] & 0x80) {     /* reliable pkt */
 480                 BT_DBG("Received seqno %u from card", bcsp->rxseq_txack);
 481
 482                 /* check the rx sequence number is as expected */
 483                 if ((bcsp->rx_skb->data[0] & 0x07) == bcsp->rxseq_txack) {
 484                         bcsp->rxseq_txack++;
 485                         bcsp->rxseq_txack %= 0x8;
 486                 } else {
 487                         /* handle re-transmitted packet or
 488                          * when packet was missed
 489                          */
 490                         BT_ERR("Out-of-order packet arrived, got %u expected %u",
 491                                bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);
 492
 493                         /* do not process out-of-order packet payload */
 494                         pass_up = 2;
 495                 }
 496
 497                 /* send current txack value to all received reliable packets */
 498                 bcsp->txack_req = 1;
 499
 500                 /* If needed, transmit an ack pkt */
 501                 hci_uart_tx_wakeup(hu);
 502         }
 503
 504         bcsp->rxack = (bcsp->rx_skb->data[0] >> 3) & 0x07;
 505         BT_DBG("Request for pkt %u from card", bcsp->rxack);
 506
 507         /* handle received ACK indications,
 508          * including those from out-of-order packets
 509          */
 510         bcsp_pkt_cull(bcsp);
 511
 512         if (pass_up != 2) {
 513                 if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
 514                     (bcsp->rx_skb->data[0] & 0x80)) {
 515                         hci_skb_pkt_type(bcsp->rx_skb) = HCI_ACLDATA_PKT;
 516                         pass_up = 1;
 517                 } else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
 518                            (bcsp->rx_skb->data[0] & 0x80)) {
 519                         hci_skb_pkt_type(bcsp->rx_skb) = HCI_EVENT_PKT;
 520                         pass_up = 1;
 521                 } else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
 522                         hci_skb_pkt_type(bcsp->rx_skb) = HCI_SCODATA_PKT;
 523                         pass_up = 1;
 524                 } else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
 525                            !(bcsp->rx_skb->data[0] & 0x80)) {
 526                         bcsp_handle_le_pkt(hu);
 527                         pass_up = 0;
 528                 } else {
 529                         pass_up = 0;
 530                 }
 531         }
 532
 533         if (pass_up == 0) {
 534                 struct hci_event_hdr hdr;
 535                 u8 desc = (bcsp->rx_skb->data[1] & 0x0f);
 536
 537                 if (desc != 0 && desc != 1) {
 538                         if (hciextn) {
 539                                 desc |= 0xc0;
 540                                 skb_pull(bcsp->rx_skb, 4);
 541                                 memcpy(skb_push(bcsp->rx_skb, 1), &desc, 1);
 542
 543                                 hdr.evt = 0xff;
 544                                 hdr.plen = bcsp->rx_skb->len;
 545                                 memcpy(skb_push(bcsp->rx_skb, HCI_EVENT_HDR_SIZE), &hdr, HCI_EVENT_HDR_SIZE);
 546                                 hci_skb_pkt_type(bcsp->rx_skb) = HCI_EVENT_PKT;
 547
 548                                 hci_recv_frame(hu->hdev, bcsp->rx_skb);
 549                         } else {
 550                                 BT_ERR("Packet for unknown channel (%u %s)",
 551                                        bcsp->rx_skb->data[1] & 0x0f,
 552                                        bcsp->rx_skb->data[0] & 0x80 ?
 553                                        "reliable" : "unreliable");
 554                                 kfree_skb(bcsp->rx_skb);
 555                         }
 556                 } else
 557                         kfree_skb(bcsp->rx_skb);
 558         } else if (pass_up == 1) {
 559                 /* Pull out BCSP hdr */
 560                 skb_pull(bcsp->rx_skb, 4);
 561
 562                 hci_recv_frame(hu->hdev, bcsp->rx_skb);
 563         } else {
 564                 /* ignore packet payload of already ACKed re-transmitted
 565                  * packets or when a packet was missed in the BCSP window
 566                  */
 567                 kfree_skb(bcsp->rx_skb);
 568         }
 569
 570         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 571         bcsp->rx_skb = NULL;
 572 }
 573
 574 static u16 bscp_get_crc(struct bcsp_struct *bcsp)
 575 {
 576         return get_unaligned_be16(&bcsp->rx_skb->data[bcsp->rx_skb->len - 2]);
 577 }
 578
 579 /* Recv data */
 580 static int bcsp_recv(struct hci_uart *hu, const void *data, int count)
 581 {
 582         struct bcsp_struct *bcsp = hu->priv;
 583         const unsigned char *ptr;
 584
 585         BT_DBG("hu %p count %d rx_state %d rx_count %ld",
 586                hu, count, bcsp->rx_state, bcsp->rx_count);
 587
 588         ptr = data;
 589         while (count) {
 590                 if (bcsp->rx_count) {
 591                         if (*ptr == 0xc0) {
 592                                 BT_ERR("Short BCSP packet");
 593                                 kfree_skb(bcsp->rx_skb);
 594                                 bcsp->rx_skb = NULL;
 595                                 bcsp->rx_state = BCSP_W4_PKT_START;
 596                                 bcsp->rx_count = 0;
 597                         } else
 598                                 bcsp_unslip_one_byte(bcsp, *ptr);
 599
 600                         ptr++; count--;
 601                         continue;
 602                 }
 603
 604                 switch (bcsp->rx_state) {
 605                 case BCSP_W4_BCSP_HDR:
 606                         if ((0xff & (u8)~(bcsp->rx_skb->data[0] + bcsp->rx_skb->data[1] +
 607                             bcsp->rx_skb->data[2])) != bcsp->rx_skb->data[3]) {
 608                                 BT_ERR("Error in BCSP hdr checksum");
 609                                 kfree_skb(bcsp->rx_skb);
 610                                 bcsp->rx_skb = NULL;
 611                                 bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 612                                 bcsp->rx_count = 0;
 613                                 continue;
 614                         }
 615                         bcsp->rx_state = BCSP_W4_DATA;
 616                         bcsp->rx_count = (bcsp->rx_skb->data[1] >> 4) +
 617                                         (bcsp->rx_skb->data[2] << 4);   /* May be 0 */
 618                         continue;
 619
 620                 case BCSP_W4_DATA:
 621                         if (bcsp->rx_skb->data[0] & 0x40) {     /* pkt with crc */
 622                                 bcsp->rx_state = BCSP_W4_CRC;
 623                                 bcsp->rx_count = 2;
 624                         } else
 625                                 bcsp_complete_rx_pkt(hu);
 626                         continue;
 627
 628                 case BCSP_W4_CRC:
 629                         if (bitrev16(bcsp->message_crc) != bscp_get_crc(bcsp)) {
 630                                 BT_ERR("Checksum failed: computed %04x received %04x",
 631                                        bitrev16(bcsp->message_crc),
 632                                        bscp_get_crc(bcsp));
 633
 634                                 kfree_skb(bcsp->rx_skb);
 635                                 bcsp->rx_skb = NULL;
 636                                 bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 637                                 bcsp->rx_count = 0;
 638                                 continue;
 639                         }
 640                         skb_trim(bcsp->rx_skb, bcsp->rx_skb->len - 2);
 641                         bcsp_complete_rx_pkt(hu);
 642                         continue;
 643
 644                 case BCSP_W4_PKT_DELIMITER:
 645                         switch (*ptr) {
 646                         case 0xc0:
 647                                 bcsp->rx_state = BCSP_W4_PKT_START;
 648                                 break;
 649                         default:
 650                                 /*BT_ERR("Ignoring byte %02x", *ptr);*/
 651                                 break;
 652                         }
 653                         ptr++; count--;
 654                         break;
 655
 656                 case BCSP_W4_PKT_START:
 657                         switch (*ptr) {
 658                         case 0xc0:
 659                                 ptr++; count--;
 660                                 break;
 661
 662                         default:
 663                                 bcsp->rx_state = BCSP_W4_BCSP_HDR;
 664                                 bcsp->rx_count = 4;
 665                                 bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
 666                                 BCSP_CRC_INIT(bcsp->message_crc);
 667
 668                                 /* Do not increment ptr or decrement count
 669                                  * Allocate packet. Max len of a BCSP pkt=
 670                                  * 0xFFF (payload) +4 (header) +2 (crc)
 671                                  */
 672
 673                                 bcsp->rx_skb = bt_skb_alloc(0x1005, GFP_ATOMIC);
 674                                 if (!bcsp->rx_skb) {
 675                                         BT_ERR("Can't allocate mem for new packet");
 676                                         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 677                                         bcsp->rx_count = 0;
 678                                         return 0;
 679                                 }
 680                                 break;
 681                         }
 682                         break;
 683                 }
 684         }
 685         return count;
 686 }
 687
 688         /* Arrange to retransmit all messages in the relq. */
 689 static void bcsp_timed_event(struct timer_list *t)
 690 {
 691         struct bcsp_struct *bcsp = from_timer(bcsp, t, tbcsp);
 692         struct hci_uart *hu = bcsp->hu;
 693         struct sk_buff *skb;
 694         unsigned long flags;
 695
 696         BT_DBG("hu %p retransmitting %u pkts", hu, bcsp->unack.qlen);
 697
 698         spin_lock_irqsave_nested(&bcsp->unack.lock, flags, SINGLE_DEPTH_NESTING);
 699
 700         while ((skb = __skb_dequeue_tail(&bcsp->unack)) != NULL) {
 701                 bcsp->msgq_txseq = (bcsp->msgq_txseq - 1) & 0x07;
 702                 skb_queue_head(&bcsp->rel, skb);
 703         }
 704
 705         spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 706
 707         hci_uart_tx_wakeup(hu);
 708 }
 709
 710 static int bcsp_open(struct hci_uart *hu)
 711 {
 712         struct bcsp_struct *bcsp;
 713
 714         BT_DBG("hu %p", hu);
 715
 716         bcsp = kzalloc(sizeof(*bcsp), GFP_KERNEL);
 717         if (!bcsp)
 718                 return -ENOMEM;
 719
 720         hu->priv = bcsp;
 721         bcsp->hu = hu;
 722         skb_queue_head_init(&bcsp->unack);
 723         skb_queue_head_init(&bcsp->rel);
 724         skb_queue_head_init(&bcsp->unrel);
 725
 726         timer_setup(&bcsp->tbcsp, bcsp_timed_event, 0);
 727
 728         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 729
 730         if (txcrc)
 731                 bcsp->use_crc = 1;
 732
 733         return 0;
 734 }
 735
 736 static int bcsp_close(struct hci_uart *hu)
 737 {
 738         struct bcsp_struct *bcsp = hu->priv;
 739
 740         timer_shutdown_sync(&bcsp->tbcsp);
 741
 742         hu->priv = NULL;
 743
 744         BT_DBG("hu %p", hu);
 745
 746         skb_queue_purge(&bcsp->unack);
 747         skb_queue_purge(&bcsp->rel);
 748         skb_queue_purge(&bcsp->unrel);
 749
 750         if (bcsp->rx_skb) {
 751                 kfree_skb(bcsp->rx_skb);
 752                 bcsp->rx_skb = NULL;
 753         }
 754
 755         kfree(bcsp);
 756         return 0;
 757 }
 758
 759 static const struct hci_uart_proto bcsp = {
 760         .id             = HCI_UART_BCSP,
 761         .name           = "BCSP",
 762         .open           = bcsp_open,
 763         .close          = bcsp_close,
 764         .enqueue        = bcsp_enqueue,
 765         .dequeue        = bcsp_dequeue,
 766         .recv           = bcsp_recv,
 767         .flush          = bcsp_flush
 768 };
 769
 770 int __init bcsp_init(void)
 771 {
 772         return hci_uart_register_proto(&bcsp);
 773 }
 774
 775 int __exit bcsp_deinit(void)
 776 {
 777         return hci_uart_unregister_proto(&bcsp);
 778 }
 779
 780 module_param(txcrc, bool, 0644);
 781 MODULE_PARM_DESC(txcrc, "Transmit CRC with every BCSP packet");
 782
 783 module_param(hciextn, bool, 0644);
 784 MODULE_PARM_DESC(hciextn, "Convert HCI Extensions into BCSP packets");