drivers/bluetooth/hci_bcsp.c

   1 /*
   2  *
   3  *  Bluetooth HCI UART driver
   4  *
   5  *  Copyright (C) 2002-2003  Fabrizio Gennari <fabrizio.gennari@philips.com>
   6  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
   7  *
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or
  12  *  (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to the Free Software
  21  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  *
  23  */
  24
  25 #include <linux/module.h>
  26
  27 #include <linux/kernel.h>
  28 #include <linux/init.h>
  29 #include <linux/types.h>
  30 #include <linux/fcntl.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/ptrace.h>
  33 #include <linux/poll.h>
  34
  35 #include <linux/slab.h>
  36 #include <linux/tty.h>
  37 #include <linux/errno.h>
  38 #include <linux/string.h>
  39 #include <linux/signal.h>
  40 #include <linux/ioctl.h>
  41 #include <linux/skbuff.h>
  42 #include <linux/bitrev.h>
  43 #include <asm/unaligned.h>
  44
  45 #include <net/bluetooth/bluetooth.h>
  46 #include <net/bluetooth/hci_core.h>
  47
  48 #include "hci_uart.h"
  49
  50 static bool txcrc = true;
  51 static bool hciextn = true;
  52
  53 #define BCSP_TXWINSIZE  4
  54
  55 #define BCSP_ACK_PKT    0x05
  56 #define BCSP_LE_PKT     0x06
  57
  58 struct bcsp_struct {
  59         struct sk_buff_head unack;      /* Unack'ed packets queue */
  60         struct sk_buff_head rel;        /* Reliable packets queue */
  61         struct sk_buff_head unrel;      /* Unreliable packets queue */
  62
  63         unsigned long rx_count;
  64         struct  sk_buff *rx_skb;
  65         u8      rxseq_txack;            /* rxseq == txack. */
  66         u8      rxack;                  /* Last packet sent by us that the peer ack'ed */
  67         struct  timer_list tbcsp;
  68         struct  hci_uart *hu;
  69
  70         enum {
  71                 BCSP_W4_PKT_DELIMITER,
  72                 BCSP_W4_PKT_START,
  73                 BCSP_W4_BCSP_HDR,
  74                 BCSP_W4_DATA,
  75                 BCSP_W4_CRC
  76         } rx_state;
  77
  78         enum {
  79                 BCSP_ESCSTATE_NOESC,
  80                 BCSP_ESCSTATE_ESC
  81         } rx_esc_state;
  82
  83         u8      use_crc;
  84         u16     message_crc;
  85         u8      txack_req;              /* Do we need to send ack's to the peer? */
  86
  87         /* Reliable packet sequence number - used to assign seq to each rel pkt. */
  88         u8      msgq_txseq;
  89 };
  90
  91 /* ---- BCSP CRC calculation ---- */
  92
  93 /* Table for calculating CRC for polynomial 0x1021, LSB processed first,
  94  * initial value 0xffff, bits shifted in reverse order.
  95  */
  96
  97 static const u16 crc_table[] = {
  98         0x0000, 0x1081, 0x2102, 0x3183,
  99         0x4204, 0x5285, 0x6306, 0x7387,
 100         0x8408, 0x9489, 0xa50a, 0xb58b,
 101         0xc60c, 0xd68d, 0xe70e, 0xf78f
 102 };
 103
 104 /* Initialise the crc calculator */
 105 #define BCSP_CRC_INIT(x) x = 0xffff
 106
 107 /* Update crc with next data byte
 108  *
 109  * Implementation note
 110  *     The data byte is treated as two nibbles.  The crc is generated
 111  *     in reverse, i.e., bits are fed into the register from the top.
 112  */
 113 static void bcsp_crc_update(u16 *crc, u8 d)
 114 {
 115         u16 reg = *crc;
 116
 117         reg = (reg >> 4) ^ crc_table[(reg ^ d) & 0x000f];
 118         reg = (reg >> 4) ^ crc_table[(reg ^ (d >> 4)) & 0x000f];
 119
 120         *crc = reg;
 121 }
 122
 123 /* ---- BCSP core ---- */
 124
 125 static void bcsp_slip_msgdelim(struct sk_buff *skb)
 126 {
 127         const char pkt_delim = 0xc0;
 128
 129         skb_put_data(skb, &pkt_delim, 1);
 130 }
 131
 132 static void bcsp_slip_one_byte(struct sk_buff *skb, u8 c)
 133 {
 134         const char esc_c0[2] = { 0xdb, 0xdc };
 135         const char esc_db[2] = { 0xdb, 0xdd };
 136
 137         switch (c) {
 138         case 0xc0:
 139                 skb_put_data(skb, &esc_c0, 2);
 140                 break;
 141         case 0xdb:
 142                 skb_put_data(skb, &esc_db, 2);
 143                 break;
 144         default:
 145                 skb_put_data(skb, &c, 1);
 146         }
 147 }
 148
 149 static int bcsp_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 150 {
 151         struct bcsp_struct *bcsp = hu->priv;
 152
 153         if (skb->len > 0xFFF) {
 154                 BT_ERR("Packet too long");
 155                 kfree_skb(skb);
 156                 return 0;
 157         }
 158
 159         switch (hci_skb_pkt_type(skb)) {
 160         case HCI_ACLDATA_PKT:
 161         case HCI_COMMAND_PKT:
 162                 skb_queue_tail(&bcsp->rel, skb);
 163                 break;
 164
 165         case HCI_SCODATA_PKT:
 166                 skb_queue_tail(&bcsp->unrel, skb);
 167                 break;
 168
 169         default:
 170                 BT_ERR("Unknown packet type");
 171                 kfree_skb(skb);
 172                 break;
 173         }
 174
 175         return 0;
 176 }
 177
 178 static struct sk_buff *bcsp_prepare_pkt(struct bcsp_struct *bcsp, u8 *data,
 179                                         int len, int pkt_type)
 180 {
 181         struct sk_buff *nskb;
 182         u8 hdr[4], chan;
 183         u16 BCSP_CRC_INIT(bcsp_txmsg_crc);
 184         int rel, i;
 185
 186         switch (pkt_type) {
 187         case HCI_ACLDATA_PKT:
 188                 chan = 6;       /* BCSP ACL channel */
 189                 rel = 1;        /* reliable channel */
 190                 break;
 191         case HCI_COMMAND_PKT:
 192                 chan = 5;       /* BCSP cmd/evt channel */
 193                 rel = 1;        /* reliable channel */
 194                 break;
 195         case HCI_SCODATA_PKT:
 196                 chan = 7;       /* BCSP SCO channel */
 197                 rel = 0;        /* unreliable channel */
 198                 break;
 199         case BCSP_LE_PKT:
 200                 chan = 1;       /* BCSP LE channel */
 201                 rel = 0;        /* unreliable channel */
 202                 break;
 203         case BCSP_ACK_PKT:
 204                 chan = 0;       /* BCSP internal channel */
 205                 rel = 0;        /* unreliable channel */
 206                 break;
 207         default:
 208                 BT_ERR("Unknown packet type");
 209                 return NULL;
 210         }
 211
 212         if (hciextn && chan == 5) {
 213                 __le16 opcode = ((struct hci_command_hdr *)data)->opcode;
 214
 215                 /* Vendor specific commands */
 216                 if (hci_opcode_ogf(__le16_to_cpu(opcode)) == 0x3f) {
 217                         u8 desc = *(data + HCI_COMMAND_HDR_SIZE);
 218
 219                         if ((desc & 0xf0) == 0xc0) {
 220                                 data += HCI_COMMAND_HDR_SIZE + 1;
 221                                 len  -= HCI_COMMAND_HDR_SIZE + 1;
 222                                 chan = desc & 0x0f;
 223                         }
 224                 }
 225         }
 226
 227         /* Max len of packet: (original len +4(bcsp hdr) +2(crc))*2
 228          * (because bytes 0xc0 and 0xdb are escaped, worst case is
 229          * when the packet is all made of 0xc0 and 0xdb :) )
 230          * + 2 (0xc0 delimiters at start and end).
 231          */
 232
 233         nskb = alloc_skb((len + 6) * 2 + 2, GFP_ATOMIC);
 234         if (!nskb)
 235                 return NULL;
 236
 237         hci_skb_pkt_type(nskb) = pkt_type;
 238
 239         bcsp_slip_msgdelim(nskb);
 240
 241         hdr[0] = bcsp->rxseq_txack << 3;
 242         bcsp->txack_req = 0;
 243         BT_DBG("We request packet no %u to card", bcsp->rxseq_txack);
 244
 245         if (rel) {
 246                 hdr[0] |= 0x80 + bcsp->msgq_txseq;
 247                 BT_DBG("Sending packet with seqno %u", bcsp->msgq_txseq);
 248                 bcsp->msgq_txseq = (bcsp->msgq_txseq + 1) & 0x07;
 249         }
 250
 251         if (bcsp->use_crc)
 252                 hdr[0] |= 0x40;
 253
 254         hdr[1] = ((len << 4) & 0xff) | chan;
 255         hdr[2] = len >> 4;
 256         hdr[3] = ~(hdr[0] + hdr[1] + hdr[2]);
 257
 258         /* Put BCSP header */
 259         for (i = 0; i < 4; i++) {
 260                 bcsp_slip_one_byte(nskb, hdr[i]);
 261
 262                 if (bcsp->use_crc)
 263                         bcsp_crc_update(&bcsp_txmsg_crc, hdr[i]);
 264         }
 265
 266         /* Put payload */
 267         for (i = 0; i < len; i++) {
 268                 bcsp_slip_one_byte(nskb, data[i]);
 269
 270                 if (bcsp->use_crc)
 271                         bcsp_crc_update(&bcsp_txmsg_crc, data[i]);
 272         }
 273
 274         /* Put CRC */
 275         if (bcsp->use_crc) {
 276                 bcsp_txmsg_crc = bitrev16(bcsp_txmsg_crc);
 277                 bcsp_slip_one_byte(nskb, (u8)((bcsp_txmsg_crc >> 8) & 0x00ff));
 278                 bcsp_slip_one_byte(nskb, (u8)(bcsp_txmsg_crc & 0x00ff));
 279         }
 280
 281         bcsp_slip_msgdelim(nskb);
 282         return nskb;
 283 }
 284
 285 /* This is a rewrite of pkt_avail in ABCSP */
 286 static struct sk_buff *bcsp_dequeue(struct hci_uart *hu)
 287 {
 288         struct bcsp_struct *bcsp = hu->priv;
 289         unsigned long flags;
 290         struct sk_buff *skb;
 291
 292         /* First of all, check for unreliable messages in the queue,
 293          * since they have priority
 294          */
 295
 296         skb = skb_dequeue(&bcsp->unrel);
 297         if (skb != NULL) {
 298                 struct sk_buff *nskb;
 299
 300                 nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len,
 301                                         hci_skb_pkt_type(skb));
 302                 if (nskb) {
 303                         kfree_skb(skb);
 304                         return nskb;
 305                 } else {
 306                         skb_queue_head(&bcsp->unrel, skb);
 307                         BT_ERR("Could not dequeue pkt because alloc_skb failed");
 308                 }
 309         }
 310
 311         /* Now, try to send a reliable pkt. We can only send a
 312          * reliable packet if the number of packets sent but not yet ack'ed
 313          * is < than the winsize
 314          */
 315
 316         spin_lock_irqsave_nested(&bcsp->unack.lock, flags, SINGLE_DEPTH_NESTING);
 317
 318         if (bcsp->unack.qlen < BCSP_TXWINSIZE) {
 319                 skb = skb_dequeue(&bcsp->rel);
 320                 if (skb != NULL) {
 321                         struct sk_buff *nskb;
 322
 323                         nskb = bcsp_prepare_pkt(bcsp, skb->data, skb->len,
 324                                                 hci_skb_pkt_type(skb));
 325                         if (nskb) {
 326                                 __skb_queue_tail(&bcsp->unack, skb);
 327                                 mod_timer(&bcsp->tbcsp, jiffies + HZ / 4);
 328                                 spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 329                                 return nskb;
 330                         } else {
 331                                 skb_queue_head(&bcsp->rel, skb);
 332                                 BT_ERR("Could not dequeue pkt because alloc_skb failed");
 333                         }
 334                 }
 335         }
 336
 337         spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 338
 339         /* We could not send a reliable packet, either because there are
 340          * none or because there are too many unack'ed pkts. Did we receive
 341          * any packets we have not acknowledged yet ?
 342          */
 343
 344         if (bcsp->txack_req) {
 345                 /* if so, craft an empty ACK pkt and send it on BCSP unreliable
 346                  * channel 0
 347                  */
 348                 struct sk_buff *nskb = bcsp_prepare_pkt(bcsp, NULL, 0, BCSP_ACK_PKT);
 349                 return nskb;
 350         }
 351
 352         /* We have nothing to send */
 353         return NULL;
 354 }
 355
 356 static int bcsp_flush(struct hci_uart *hu)
 357 {
 358         BT_DBG("hu %p", hu);
 359         return 0;
 360 }
 361
 362 /* Remove ack'ed packets */
 363 static void bcsp_pkt_cull(struct bcsp_struct *bcsp)
 364 {
 365         struct sk_buff *skb, *tmp;
 366         unsigned long flags;
 367         int i, pkts_to_be_removed;
 368         u8 seqno;
 369
 370         spin_lock_irqsave(&bcsp->unack.lock, flags);
 371
 372         pkts_to_be_removed = skb_queue_len(&bcsp->unack);
 373         seqno = bcsp->msgq_txseq;
 374
 375         while (pkts_to_be_removed) {
 376                 if (bcsp->rxack == seqno)
 377                         break;
 378                 pkts_to_be_removed--;
 379                 seqno = (seqno - 1) & 0x07;
 380         }
 381
 382         if (bcsp->rxack != seqno)
 383                 BT_ERR("Peer acked invalid packet");
 384
 385         BT_DBG("Removing %u pkts out of %u, up to seqno %u",
 386                pkts_to_be_removed, skb_queue_len(&bcsp->unack),
 387                (seqno - 1) & 0x07);
 388
 389         i = 0;
 390         skb_queue_walk_safe(&bcsp->unack, skb, tmp) {
 391                 if (i >= pkts_to_be_removed)
 392                         break;
 393                 i++;
 394
 395                 __skb_unlink(skb, &bcsp->unack);
 396                 kfree_skb(skb);
 397         }
 398
 399         if (skb_queue_empty(&bcsp->unack))
 400                 del_timer(&bcsp->tbcsp);
 401
 402         spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 403
 404         if (i != pkts_to_be_removed)
 405                 BT_ERR("Removed only %u out of %u pkts", i, pkts_to_be_removed);
 406 }
 407
 408 /* Handle BCSP link-establishment packets. When we
 409  * detect a "sync" packet, symptom that the BT module has reset,
 410  * we do nothing :) (yet)
 411  */
 412 static void bcsp_handle_le_pkt(struct hci_uart *hu)
 413 {
 414         struct bcsp_struct *bcsp = hu->priv;
 415         u8 conf_pkt[4]     = { 0xad, 0xef, 0xac, 0xed };
 416         u8 conf_rsp_pkt[4] = { 0xde, 0xad, 0xd0, 0xd0 };
 417         u8 sync_pkt[4]     = { 0xda, 0xdc, 0xed, 0xed };
 418
 419         /* spot "conf" pkts and reply with a "conf rsp" pkt */
 420         if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
 421             !memcmp(&bcsp->rx_skb->data[4], conf_pkt, 4)) {
 422                 struct sk_buff *nskb = alloc_skb(4, GFP_ATOMIC);
 423
 424                 BT_DBG("Found a LE conf pkt");
 425                 if (!nskb)
 426                         return;
 427                 skb_put_data(nskb, conf_rsp_pkt, 4);
 428                 hci_skb_pkt_type(nskb) = BCSP_LE_PKT;
 429
 430                 skb_queue_head(&bcsp->unrel, nskb);
 431                 hci_uart_tx_wakeup(hu);
 432         }
 433         /* Spot "sync" pkts. If we find one...disaster! */
 434         else if (bcsp->rx_skb->data[1] >> 4 == 4 && bcsp->rx_skb->data[2] == 0 &&
 435                  !memcmp(&bcsp->rx_skb->data[4], sync_pkt, 4)) {
 436                 BT_ERR("Found a LE sync pkt, card has reset");
 437         }
 438 }
 439
 440 static inline void bcsp_unslip_one_byte(struct bcsp_struct *bcsp, unsigned char byte)
 441 {
 442         const u8 c0 = 0xc0, db = 0xdb;
 443
 444         switch (bcsp->rx_esc_state) {
 445         case BCSP_ESCSTATE_NOESC:
 446                 switch (byte) {
 447                 case 0xdb:
 448                         bcsp->rx_esc_state = BCSP_ESCSTATE_ESC;
 449                         break;
 450                 default:
 451                         skb_put_data(bcsp->rx_skb, &byte, 1);
 452                         if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
 453                             bcsp->rx_state != BCSP_W4_CRC)
 454                                 bcsp_crc_update(&bcsp->message_crc, byte);
 455                         bcsp->rx_count--;
 456                 }
 457                 break;
 458
 459         case BCSP_ESCSTATE_ESC:
 460                 switch (byte) {
 461                 case 0xdc:
 462                         skb_put_data(bcsp->rx_skb, &c0, 1);
 463                         if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
 464                             bcsp->rx_state != BCSP_W4_CRC)
 465                                 bcsp_crc_update(&bcsp->message_crc, 0xc0);
 466                         bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
 467                         bcsp->rx_count--;
 468                         break;
 469
 470                 case 0xdd:
 471                         skb_put_data(bcsp->rx_skb, &db, 1);
 472                         if ((bcsp->rx_skb->data[0] & 0x40) != 0 &&
 473                             bcsp->rx_state != BCSP_W4_CRC)
 474                                 bcsp_crc_update(&bcsp->message_crc, 0xdb);
 475                         bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
 476                         bcsp->rx_count--;
 477                         break;
 478
 479                 default:
 480                         BT_ERR("Invalid byte %02x after esc byte", byte);
 481                         kfree_skb(bcsp->rx_skb);
 482                         bcsp->rx_skb = NULL;
 483                         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 484                         bcsp->rx_count = 0;
 485                 }
 486         }
 487 }
 488
 489 static void bcsp_complete_rx_pkt(struct hci_uart *hu)
 490 {
 491         struct bcsp_struct *bcsp = hu->priv;
 492         int pass_up = 0;
 493
 494         if (bcsp->rx_skb->data[0] & 0x80) {     /* reliable pkt */
 495                 BT_DBG("Received seqno %u from card", bcsp->rxseq_txack);
 496
 497                 /* check the rx sequence number is as expected */
 498                 if ((bcsp->rx_skb->data[0] & 0x07) == bcsp->rxseq_txack) {
 499                         bcsp->rxseq_txack++;
 500                         bcsp->rxseq_txack %= 0x8;
 501                 } else {
 502                         /* handle re-transmitted packet or
 503                          * when packet was missed
 504                          */
 505                         BT_ERR("Out-of-order packet arrived, got %u expected %u",
 506                                bcsp->rx_skb->data[0] & 0x07, bcsp->rxseq_txack);
 507
 508                         /* do not process out-of-order packet payload */
 509                         pass_up = 2;
 510                 }
 511
 512                 /* send current txack value to all received reliable packets */
 513                 bcsp->txack_req = 1;
 514
 515                 /* If needed, transmit an ack pkt */
 516                 hci_uart_tx_wakeup(hu);
 517         }
 518
 519         bcsp->rxack = (bcsp->rx_skb->data[0] >> 3) & 0x07;
 520         BT_DBG("Request for pkt %u from card", bcsp->rxack);
 521
 522         /* handle received ACK indications,
 523          * including those from out-of-order packets
 524          */
 525         bcsp_pkt_cull(bcsp);
 526
 527         if (pass_up != 2) {
 528                 if ((bcsp->rx_skb->data[1] & 0x0f) == 6 &&
 529                     (bcsp->rx_skb->data[0] & 0x80)) {
 530                         hci_skb_pkt_type(bcsp->rx_skb) = HCI_ACLDATA_PKT;
 531                         pass_up = 1;
 532                 } else if ((bcsp->rx_skb->data[1] & 0x0f) == 5 &&
 533                            (bcsp->rx_skb->data[0] & 0x80)) {
 534                         hci_skb_pkt_type(bcsp->rx_skb) = HCI_EVENT_PKT;
 535                         pass_up = 1;
 536                 } else if ((bcsp->rx_skb->data[1] & 0x0f) == 7) {
 537                         hci_skb_pkt_type(bcsp->rx_skb) = HCI_SCODATA_PKT;
 538                         pass_up = 1;
 539                 } else if ((bcsp->rx_skb->data[1] & 0x0f) == 1 &&
 540                            !(bcsp->rx_skb->data[0] & 0x80)) {
 541                         bcsp_handle_le_pkt(hu);
 542                         pass_up = 0;
 543                 } else {
 544                         pass_up = 0;
 545                 }
 546         }
 547
 548         if (pass_up == 0) {
 549                 struct hci_event_hdr hdr;
 550                 u8 desc = (bcsp->rx_skb->data[1] & 0x0f);
 551
 552                 if (desc != 0 && desc != 1) {
 553                         if (hciextn) {
 554                                 desc |= 0xc0;
 555                                 skb_pull(bcsp->rx_skb, 4);
 556                                 memcpy(skb_push(bcsp->rx_skb, 1), &desc, 1);
 557
 558                                 hdr.evt = 0xff;
 559                                 hdr.plen = bcsp->rx_skb->len;
 560                                 memcpy(skb_push(bcsp->rx_skb, HCI_EVENT_HDR_SIZE), &hdr, HCI_EVENT_HDR_SIZE);
 561                                 hci_skb_pkt_type(bcsp->rx_skb) = HCI_EVENT_PKT;
 562
 563                                 hci_recv_frame(hu->hdev, bcsp->rx_skb);
 564                         } else {
 565                                 BT_ERR("Packet for unknown channel (%u %s)",
 566                                        bcsp->rx_skb->data[1] & 0x0f,
 567                                        bcsp->rx_skb->data[0] & 0x80 ?
 568                                        "reliable" : "unreliable");
 569                                 kfree_skb(bcsp->rx_skb);
 570                         }
 571                 } else
 572                         kfree_skb(bcsp->rx_skb);
 573         } else if (pass_up == 1) {
 574                 /* Pull out BCSP hdr */
 575                 skb_pull(bcsp->rx_skb, 4);
 576
 577                 hci_recv_frame(hu->hdev, bcsp->rx_skb);
 578         } else {
 579                 /* ignore packet payload of already ACKed re-transmitted
 580                  * packets or when a packet was missed in the BCSP window
 581                  */
 582                 kfree_skb(bcsp->rx_skb);
 583         }
 584
 585         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 586         bcsp->rx_skb = NULL;
 587 }
 588
 589 static u16 bscp_get_crc(struct bcsp_struct *bcsp)
 590 {
 591         return get_unaligned_be16(&bcsp->rx_skb->data[bcsp->rx_skb->len - 2]);
 592 }
 593
 594 /* Recv data */
 595 static int bcsp_recv(struct hci_uart *hu, const void *data, int count)
 596 {
 597         struct bcsp_struct *bcsp = hu->priv;
 598         const unsigned char *ptr;
 599
 600         BT_DBG("hu %p count %d rx_state %d rx_count %ld",
 601                hu, count, bcsp->rx_state, bcsp->rx_count);
 602
 603         ptr = data;
 604         while (count) {
 605                 if (bcsp->rx_count) {
 606                         if (*ptr == 0xc0) {
 607                                 BT_ERR("Short BCSP packet");
 608                                 kfree_skb(bcsp->rx_skb);
 609                                 bcsp->rx_state = BCSP_W4_PKT_START;
 610                                 bcsp->rx_count = 0;
 611                         } else
 612                                 bcsp_unslip_one_byte(bcsp, *ptr);
 613
 614                         ptr++; count--;
 615                         continue;
 616                 }
 617
 618                 switch (bcsp->rx_state) {
 619                 case BCSP_W4_BCSP_HDR:
 620                         if ((0xff & (u8)~(bcsp->rx_skb->data[0] + bcsp->rx_skb->data[1] +
 621                             bcsp->rx_skb->data[2])) != bcsp->rx_skb->data[3]) {
 622                                 BT_ERR("Error in BCSP hdr checksum");
 623                                 kfree_skb(bcsp->rx_skb);
 624                                 bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 625                                 bcsp->rx_count = 0;
 626                                 continue;
 627                         }
 628                         bcsp->rx_state = BCSP_W4_DATA;
 629                         bcsp->rx_count = (bcsp->rx_skb->data[1] >> 4) +
 630                                         (bcsp->rx_skb->data[2] << 4);   /* May be 0 */
 631                         continue;
 632
 633                 case BCSP_W4_DATA:
 634                         if (bcsp->rx_skb->data[0] & 0x40) {     /* pkt with crc */
 635                                 bcsp->rx_state = BCSP_W4_CRC;
 636                                 bcsp->rx_count = 2;
 637                         } else
 638                                 bcsp_complete_rx_pkt(hu);
 639                         continue;
 640
 641                 case BCSP_W4_CRC:
 642                         if (bitrev16(bcsp->message_crc) != bscp_get_crc(bcsp)) {
 643                                 BT_ERR("Checksum failed: computed %04x received %04x",
 644                                        bitrev16(bcsp->message_crc),
 645                                        bscp_get_crc(bcsp));
 646
 647                                 kfree_skb(bcsp->rx_skb);
 648                                 bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 649                                 bcsp->rx_count = 0;
 650                                 continue;
 651                         }
 652                         skb_trim(bcsp->rx_skb, bcsp->rx_skb->len - 2);
 653                         bcsp_complete_rx_pkt(hu);
 654                         continue;
 655
 656                 case BCSP_W4_PKT_DELIMITER:
 657                         switch (*ptr) {
 658                         case 0xc0:
 659                                 bcsp->rx_state = BCSP_W4_PKT_START;
 660                                 break;
 661                         default:
 662                                 /*BT_ERR("Ignoring byte %02x", *ptr);*/
 663                                 break;
 664                         }
 665                         ptr++; count--;
 666                         break;
 667
 668                 case BCSP_W4_PKT_START:
 669                         switch (*ptr) {
 670                         case 0xc0:
 671                                 ptr++; count--;
 672                                 break;
 673
 674                         default:
 675                                 bcsp->rx_state = BCSP_W4_BCSP_HDR;
 676                                 bcsp->rx_count = 4;
 677                                 bcsp->rx_esc_state = BCSP_ESCSTATE_NOESC;
 678                                 BCSP_CRC_INIT(bcsp->message_crc);
 679
 680                                 /* Do not increment ptr or decrement count
 681                                  * Allocate packet. Max len of a BCSP pkt=
 682                                  * 0xFFF (payload) +4 (header) +2 (crc)
 683                                  */
 684
 685                                 bcsp->rx_skb = bt_skb_alloc(0x1005, GFP_ATOMIC);
 686                                 if (!bcsp->rx_skb) {
 687                                         BT_ERR("Can't allocate mem for new packet");
 688                                         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 689                                         bcsp->rx_count = 0;
 690                                         return 0;
 691                                 }
 692                                 break;
 693                         }
 694                         break;
 695                 }
 696         }
 697         return count;
 698 }
 699
 700         /* Arrange to retransmit all messages in the relq. */
 701 static void bcsp_timed_event(struct timer_list *t)
 702 {
 703         struct bcsp_struct *bcsp = from_timer(bcsp, t, tbcsp);
 704         struct hci_uart *hu = bcsp->hu;
 705         struct sk_buff *skb;
 706         unsigned long flags;
 707
 708         BT_DBG("hu %p retransmitting %u pkts", hu, bcsp->unack.qlen);
 709
 710         spin_lock_irqsave_nested(&bcsp->unack.lock, flags, SINGLE_DEPTH_NESTING);
 711
 712         while ((skb = __skb_dequeue_tail(&bcsp->unack)) != NULL) {
 713                 bcsp->msgq_txseq = (bcsp->msgq_txseq - 1) & 0x07;
 714                 skb_queue_head(&bcsp->rel, skb);
 715         }
 716
 717         spin_unlock_irqrestore(&bcsp->unack.lock, flags);
 718
 719         hci_uart_tx_wakeup(hu);
 720 }
 721
 722 static int bcsp_open(struct hci_uart *hu)
 723 {
 724         struct bcsp_struct *bcsp;
 725
 726         BT_DBG("hu %p", hu);
 727
 728         bcsp = kzalloc(sizeof(*bcsp), GFP_KERNEL);
 729         if (!bcsp)
 730                 return -ENOMEM;
 731
 732         hu->priv = bcsp;
 733         bcsp->hu = hu;
 734         skb_queue_head_init(&bcsp->unack);
 735         skb_queue_head_init(&bcsp->rel);
 736         skb_queue_head_init(&bcsp->unrel);
 737
 738         timer_setup(&bcsp->tbcsp, bcsp_timed_event, 0);
 739
 740         bcsp->rx_state = BCSP_W4_PKT_DELIMITER;
 741
 742         if (txcrc)
 743                 bcsp->use_crc = 1;
 744
 745         return 0;
 746 }
 747
 748 static int bcsp_close(struct hci_uart *hu)
 749 {
 750         struct bcsp_struct *bcsp = hu->priv;
 751
 752         del_timer_sync(&bcsp->tbcsp);
 753
 754         hu->priv = NULL;
 755
 756         BT_DBG("hu %p", hu);
 757
 758         skb_queue_purge(&bcsp->unack);
 759         skb_queue_purge(&bcsp->rel);
 760         skb_queue_purge(&bcsp->unrel);
 761
 762         kfree(bcsp);
 763         return 0;
 764 }
 765
 766 static const struct hci_uart_proto bcsp = {
 767         .id             = HCI_UART_BCSP,
 768         .name           = "BCSP",
 769         .open           = bcsp_open,
 770         .close          = bcsp_close,
 771         .enqueue        = bcsp_enqueue,
 772         .dequeue        = bcsp_dequeue,
 773         .recv           = bcsp_recv,
 774         .flush          = bcsp_flush
 775 };
 776
 777 int __init bcsp_init(void)
 778 {
 779         return hci_uart_register_proto(&bcsp);
 780 }
 781
 782 int __exit bcsp_deinit(void)
 783 {
 784         return hci_uart_unregister_proto(&bcsp);
 785 }
 786
 787 module_param(txcrc, bool, 0644);
 788 MODULE_PARM_DESC(txcrc, "Transmit CRC with every BCSP packet");
 789
 790 module_param(hciextn, bool, 0644);
 791 MODULE_PARM_DESC(hciextn, "Convert HCI Extensions into BCSP packets");