drivers/bluetooth/hci_ll.c

   1 /*
   2  *  Texas Instruments' Bluetooth HCILL UART protocol
   3  *
   4  *  HCILL (HCI Low Level) is a Texas Instruments' power management
   5  *  protocol extension to H4.
   6  *
   7  *  Copyright (C) 2007 Texas Instruments, Inc.
   8  *
   9  *  Written by Ohad Ben-Cohen <ohad@bencohen.org>
  10  *
  11  *  Acknowledgements:
  12  *  This file is based on hci_h4.c, which was written
  13  *  by Maxim Krasnyansky and Marcel Holtmann.
  14  *
  15  *  This program is free software; you can redistribute it and/or modify
  16  *  it under the terms of the GNU General Public License version 2
  17  *  as published by the Free Software Foundation
  18  *
  19  *  This program is distributed in the hope that it will be useful,
  20  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  *  GNU General Public License for more details.
  23  *
  24  *  You should have received a copy of the GNU General Public License
  25  *  along with this program; if not, write to the Free Software
  26  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  27  *
  28  */
  29
  30 #include <linux/module.h>
  31 #include <linux/kernel.h>
  32
  33 #include <linux/init.h>
  34 #include <linux/sched.h>
  35 #include <linux/types.h>
  36 #include <linux/fcntl.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/ptrace.h>
  39 #include <linux/poll.h>
  40
  41 #include <linux/slab.h>
  42 #include <linux/tty.h>
  43 #include <linux/errno.h>
  44 #include <linux/string.h>
  45 #include <linux/signal.h>
  46 #include <linux/ioctl.h>
  47 #include <linux/skbuff.h>
  48
  49 #include <net/bluetooth/bluetooth.h>
  50 #include <net/bluetooth/hci_core.h>
  51
  52 #include "hci_uart.h"
  53
  54 /* HCILL commands */
  55 #define HCILL_GO_TO_SLEEP_IND   0x30
  56 #define HCILL_GO_TO_SLEEP_ACK   0x31
  57 #define HCILL_WAKE_UP_IND       0x32
  58 #define HCILL_WAKE_UP_ACK       0x33
  59
  60 /* HCILL receiver States */
  61 #define HCILL_W4_PACKET_TYPE    0
  62 #define HCILL_W4_EVENT_HDR      1
  63 #define HCILL_W4_ACL_HDR        2
  64 #define HCILL_W4_SCO_HDR        3
  65 #define HCILL_W4_DATA           4
  66
  67 /* HCILL states */
  68 enum hcill_states_e {
  69         HCILL_ASLEEP,
  70         HCILL_ASLEEP_TO_AWAKE,
  71         HCILL_AWAKE,
  72         HCILL_AWAKE_TO_ASLEEP
  73 };
  74
  75 struct hcill_cmd {
  76         u8 cmd;
  77 } __packed;
  78
  79 struct ll_struct {
  80         unsigned long rx_state;
  81         unsigned long rx_count;
  82         struct sk_buff *rx_skb;
  83         struct sk_buff_head txq;
  84         spinlock_t hcill_lock;          /* HCILL state lock     */
  85         unsigned long hcill_state;      /* HCILL power state    */
  86         struct sk_buff_head tx_wait_q;  /* HCILL wait queue     */
  87 };
  88
  89 /*
  90  * Builds and sends an HCILL command packet.
  91  * These are very simple packets with only 1 cmd byte
  92  */
  93 static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
  94 {
  95         int err = 0;
  96         struct sk_buff *skb = NULL;
  97         struct ll_struct *ll = hu->priv;
  98         struct hcill_cmd *hcill_packet;
  99
 100         BT_DBG("hu %p cmd 0x%x", hu, cmd);
 101
 102         /* allocate packet */
 103         skb = bt_skb_alloc(1, GFP_ATOMIC);
 104         if (!skb) {
 105                 BT_ERR("cannot allocate memory for HCILL packet");
 106                 err = -ENOMEM;
 107                 goto out;
 108         }
 109
 110         /* prepare packet */
 111         hcill_packet = (struct hcill_cmd *) skb_put(skb, 1);
 112         hcill_packet->cmd = cmd;
 113         skb->dev = (void *) hu->hdev;
 114
 115         /* send packet */
 116         skb_queue_tail(&ll->txq, skb);
 117 out:
 118         return err;
 119 }
 120
 121 /* Initialize protocol */
 122 static int ll_open(struct hci_uart *hu)
 123 {
 124         struct ll_struct *ll;
 125
 126         BT_DBG("hu %p", hu);
 127
 128         ll = kzalloc(sizeof(*ll), GFP_ATOMIC);
 129         if (!ll)
 130                 return -ENOMEM;
 131
 132         skb_queue_head_init(&ll->txq);
 133         skb_queue_head_init(&ll->tx_wait_q);
 134         spin_lock_init(&ll->hcill_lock);
 135
 136         ll->hcill_state = HCILL_AWAKE;
 137
 138         hu->priv = ll;
 139
 140         return 0;
 141 }
 142
 143 /* Flush protocol data */
 144 static int ll_flush(struct hci_uart *hu)
 145 {
 146         struct ll_struct *ll = hu->priv;
 147
 148         BT_DBG("hu %p", hu);
 149
 150         skb_queue_purge(&ll->tx_wait_q);
 151         skb_queue_purge(&ll->txq);
 152
 153         return 0;
 154 }
 155
 156 /* Close protocol */
 157 static int ll_close(struct hci_uart *hu)
 158 {
 159         struct ll_struct *ll = hu->priv;
 160
 161         BT_DBG("hu %p", hu);
 162
 163         skb_queue_purge(&ll->tx_wait_q);
 164         skb_queue_purge(&ll->txq);
 165
 166         kfree_skb(ll->rx_skb);
 167
 168         hu->priv = NULL;
 169
 170         kfree(ll);
 171
 172         return 0;
 173 }
 174
 175 /*
 176  * internal function, which does common work of the device wake up process:
 177  * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
 178  * 2. changes internal state to HCILL_AWAKE.
 179  * Note: assumes that hcill_lock spinlock is taken,
 180  * shouldn't be called otherwise!
 181  */
 182 static void __ll_do_awake(struct ll_struct *ll)
 183 {
 184         struct sk_buff *skb = NULL;
 185
 186         while ((skb = skb_dequeue(&ll->tx_wait_q)))
 187                 skb_queue_tail(&ll->txq, skb);
 188
 189         ll->hcill_state = HCILL_AWAKE;
 190 }
 191
 192 /*
 193  * Called upon a wake-up-indication from the device
 194  */
 195 static void ll_device_want_to_wakeup(struct hci_uart *hu)
 196 {
 197         unsigned long flags;
 198         struct ll_struct *ll = hu->priv;
 199
 200         BT_DBG("hu %p", hu);
 201
 202         /* lock hcill state */
 203         spin_lock_irqsave(&ll->hcill_lock, flags);
 204
 205         switch (ll->hcill_state) {
 206         case HCILL_ASLEEP_TO_AWAKE:
 207                 /*
 208                  * This state means that both the host and the BRF chip
 209                  * have simultaneously sent a wake-up-indication packet.
 210                  * Traditionaly, in this case, receiving a wake-up-indication
 211                  * was enough and an additional wake-up-ack wasn't needed.
 212                  * This has changed with the BRF6350, which does require an
 213                  * explicit wake-up-ack. Other BRF versions, which do not
 214                  * require an explicit ack here, do accept it, thus it is
 215                  * perfectly safe to always send one.
 216                  */
 217                 BT_DBG("dual wake-up-indication");
 218                 /* deliberate fall-through - do not add break */
 219         case HCILL_ASLEEP:
 220                 /* acknowledge device wake up */
 221                 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
 222                         BT_ERR("cannot acknowledge device wake up");
 223                         goto out;
 224                 }
 225                 break;
 226         default:
 227                 /* any other state is illegal */
 228                 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
 229                 break;
 230         }
 231
 232         /* send pending packets and change state to HCILL_AWAKE */
 233         __ll_do_awake(ll);
 234
 235 out:
 236         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 237
 238         /* actually send the packets */
 239         hci_uart_tx_wakeup(hu);
 240 }
 241
 242 /*
 243  * Called upon a sleep-indication from the device
 244  */
 245 static void ll_device_want_to_sleep(struct hci_uart *hu)
 246 {
 247         unsigned long flags;
 248         struct ll_struct *ll = hu->priv;
 249
 250         BT_DBG("hu %p", hu);
 251
 252         /* lock hcill state */
 253         spin_lock_irqsave(&ll->hcill_lock, flags);
 254
 255         /* sanity check */
 256         if (ll->hcill_state != HCILL_AWAKE)
 257                 BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
 258
 259         /* acknowledge device sleep */
 260         if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
 261                 BT_ERR("cannot acknowledge device sleep");
 262                 goto out;
 263         }
 264
 265         /* update state */
 266         ll->hcill_state = HCILL_ASLEEP;
 267
 268 out:
 269         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 270
 271         /* actually send the sleep ack packet */
 272         hci_uart_tx_wakeup(hu);
 273 }
 274
 275 /*
 276  * Called upon wake-up-acknowledgement from the device
 277  */
 278 static void ll_device_woke_up(struct hci_uart *hu)
 279 {
 280         unsigned long flags;
 281         struct ll_struct *ll = hu->priv;
 282
 283         BT_DBG("hu %p", hu);
 284
 285         /* lock hcill state */
 286         spin_lock_irqsave(&ll->hcill_lock, flags);
 287
 288         /* sanity check */
 289         if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
 290                 BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
 291
 292         /* send pending packets and change state to HCILL_AWAKE */
 293         __ll_do_awake(ll);
 294
 295         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 296
 297         /* actually send the packets */
 298         hci_uart_tx_wakeup(hu);
 299 }
 300
 301 /* Enqueue frame for transmittion (padding, crc, etc) */
 302 /* may be called from two simultaneous tasklets */
 303 static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 304 {
 305         unsigned long flags = 0;
 306         struct ll_struct *ll = hu->priv;
 307
 308         BT_DBG("hu %p skb %p", hu, skb);
 309
 310         /* Prepend skb with frame type */
 311         memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
 312
 313         /* lock hcill state */
 314         spin_lock_irqsave(&ll->hcill_lock, flags);
 315
 316         /* act according to current state */
 317         switch (ll->hcill_state) {
 318         case HCILL_AWAKE:
 319                 BT_DBG("device awake, sending normally");
 320                 skb_queue_tail(&ll->txq, skb);
 321                 break;
 322         case HCILL_ASLEEP:
 323                 BT_DBG("device asleep, waking up and queueing packet");
 324                 /* save packet for later */
 325                 skb_queue_tail(&ll->tx_wait_q, skb);
 326                 /* awake device */
 327                 if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
 328                         BT_ERR("cannot wake up device");
 329                         break;
 330                 }
 331                 ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
 332                 break;
 333         case HCILL_ASLEEP_TO_AWAKE:
 334                 BT_DBG("device waking up, queueing packet");
 335                 /* transient state; just keep packet for later */
 336                 skb_queue_tail(&ll->tx_wait_q, skb);
 337                 break;
 338         default:
 339                 BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
 340                 kfree_skb(skb);
 341                 break;
 342         }
 343
 344         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 345
 346         return 0;
 347 }
 348
 349 static inline int ll_check_data_len(struct ll_struct *ll, int len)
 350 {
 351         register int room = skb_tailroom(ll->rx_skb);
 352
 353         BT_DBG("len %d room %d", len, room);
 354
 355         if (!len) {
 356                 hci_recv_frame(ll->rx_skb);
 357         } else if (len > room) {
 358                 BT_ERR("Data length is too large");
 359                 kfree_skb(ll->rx_skb);
 360         } else {
 361                 ll->rx_state = HCILL_W4_DATA;
 362                 ll->rx_count = len;
 363                 return len;
 364         }
 365
 366         ll->rx_state = HCILL_W4_PACKET_TYPE;
 367         ll->rx_skb   = NULL;
 368         ll->rx_count = 0;
 369
 370         return 0;
 371 }
 372
 373 /* Recv data */
 374 static int ll_recv(struct hci_uart *hu, void *data, int count)
 375 {
 376         struct ll_struct *ll = hu->priv;
 377         register char *ptr;
 378         struct hci_event_hdr *eh;
 379         struct hci_acl_hdr   *ah;
 380         struct hci_sco_hdr   *sh;
 381         register int len, type, dlen;
 382
 383         BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
 384
 385         ptr = data;
 386         while (count) {
 387                 if (ll->rx_count) {
 388                         len = min_t(unsigned int, ll->rx_count, count);
 389                         memcpy(skb_put(ll->rx_skb, len), ptr, len);
 390                         ll->rx_count -= len; count -= len; ptr += len;
 391
 392                         if (ll->rx_count)
 393                                 continue;
 394
 395                         switch (ll->rx_state) {
 396                         case HCILL_W4_DATA:
 397                                 BT_DBG("Complete data");
 398                                 hci_recv_frame(ll->rx_skb);
 399
 400                                 ll->rx_state = HCILL_W4_PACKET_TYPE;
 401                                 ll->rx_skb = NULL;
 402                                 continue;
 403
 404                         case HCILL_W4_EVENT_HDR:
 405                                 eh = hci_event_hdr(ll->rx_skb);
 406
 407                                 BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
 408
 409                                 ll_check_data_len(ll, eh->plen);
 410                                 continue;
 411
 412                         case HCILL_W4_ACL_HDR:
 413                                 ah = hci_acl_hdr(ll->rx_skb);
 414                                 dlen = __le16_to_cpu(ah->dlen);
 415
 416                                 BT_DBG("ACL header: dlen %d", dlen);
 417
 418                                 ll_check_data_len(ll, dlen);
 419                                 continue;
 420
 421                         case HCILL_W4_SCO_HDR:
 422                                 sh = hci_sco_hdr(ll->rx_skb);
 423
 424                                 BT_DBG("SCO header: dlen %d", sh->dlen);
 425
 426                                 ll_check_data_len(ll, sh->dlen);
 427                                 continue;
 428                         }
 429                 }
 430
 431                 /* HCILL_W4_PACKET_TYPE */
 432                 switch (*ptr) {
 433                 case HCI_EVENT_PKT:
 434                         BT_DBG("Event packet");
 435                         ll->rx_state = HCILL_W4_EVENT_HDR;
 436                         ll->rx_count = HCI_EVENT_HDR_SIZE;
 437                         type = HCI_EVENT_PKT;
 438                         break;
 439
 440                 case HCI_ACLDATA_PKT:
 441                         BT_DBG("ACL packet");
 442                         ll->rx_state = HCILL_W4_ACL_HDR;
 443                         ll->rx_count = HCI_ACL_HDR_SIZE;
 444                         type = HCI_ACLDATA_PKT;
 445                         break;
 446
 447                 case HCI_SCODATA_PKT:
 448                         BT_DBG("SCO packet");
 449                         ll->rx_state = HCILL_W4_SCO_HDR;
 450                         ll->rx_count = HCI_SCO_HDR_SIZE;
 451                         type = HCI_SCODATA_PKT;
 452                         break;
 453
 454                 /* HCILL signals */
 455                 case HCILL_GO_TO_SLEEP_IND:
 456                         BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
 457                         ll_device_want_to_sleep(hu);
 458                         ptr++; count--;
 459                         continue;
 460
 461                 case HCILL_GO_TO_SLEEP_ACK:
 462                         /* shouldn't happen */
 463                         BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
 464                         ptr++; count--;
 465                         continue;
 466
 467                 case HCILL_WAKE_UP_IND:
 468                         BT_DBG("HCILL_WAKE_UP_IND packet");
 469                         ll_device_want_to_wakeup(hu);
 470                         ptr++; count--;
 471                         continue;
 472
 473                 case HCILL_WAKE_UP_ACK:
 474                         BT_DBG("HCILL_WAKE_UP_ACK packet");
 475                         ll_device_woke_up(hu);
 476                         ptr++; count--;
 477                         continue;
 478
 479                 default:
 480                         BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
 481                         hu->hdev->stat.err_rx++;
 482                         ptr++; count--;
 483                         continue;
 484                 };
 485
 486                 ptr++; count--;
 487
 488                 /* Allocate packet */
 489                 ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
 490                 if (!ll->rx_skb) {
 491                         BT_ERR("Can't allocate mem for new packet");
 492                         ll->rx_state = HCILL_W4_PACKET_TYPE;
 493                         ll->rx_count = 0;
 494                         return -ENOMEM;
 495                 }
 496
 497                 ll->rx_skb->dev = (void *) hu->hdev;
 498                 bt_cb(ll->rx_skb)->pkt_type = type;
 499         }
 500
 501         return count;
 502 }
 503
 504 static struct sk_buff *ll_dequeue(struct hci_uart *hu)
 505 {
 506         struct ll_struct *ll = hu->priv;
 507         return skb_dequeue(&ll->txq);
 508 }
 509
 510 static struct hci_uart_proto llp = {
 511         .id             = HCI_UART_LL,
 512         .open           = ll_open,
 513         .close          = ll_close,
 514         .recv           = ll_recv,
 515         .enqueue        = ll_enqueue,
 516         .dequeue        = ll_dequeue,
 517         .flush          = ll_flush,
 518 };
 519
 520 int __init ll_init(void)
 521 {
 522         int err = hci_uart_register_proto(&llp);
 523
 524         if (!err)
 525                 BT_INFO("HCILL protocol initialized");
 526         else
 527                 BT_ERR("HCILL protocol registration failed");
 528
 529         return err;
 530 }
 531
 532 int __exit ll_deinit(void)
 533 {
 534         return hci_uart_unregister_proto(&llp);
 535 }