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 } __attribute__((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         if (ll->rx_skb)
 167                 kfree_skb(ll->rx_skb);
 168
 169         hu->priv = NULL;
 170
 171         kfree(ll);
 172
 173         return 0;
 174 }
 175
 176 /*
 177  * internal function, which does common work of the device wake up process:
 178  * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
 179  * 2. changes internal state to HCILL_AWAKE.
 180  * Note: assumes that hcill_lock spinlock is taken,
 181  * shouldn't be called otherwise!
 182  */
 183 static void __ll_do_awake(struct ll_struct *ll)
 184 {
 185         struct sk_buff *skb = NULL;
 186
 187         while ((skb = skb_dequeue(&ll->tx_wait_q)))
 188                 skb_queue_tail(&ll->txq, skb);
 189
 190         ll->hcill_state = HCILL_AWAKE;
 191 }
 192
 193 /*
 194  * Called upon a wake-up-indication from the device
 195  */
 196 static void ll_device_want_to_wakeup(struct hci_uart *hu)
 197 {
 198         unsigned long flags;
 199         struct ll_struct *ll = hu->priv;
 200
 201         BT_DBG("hu %p", hu);
 202
 203         /* lock hcill state */
 204         spin_lock_irqsave(&ll->hcill_lock, flags);
 205
 206         switch (ll->hcill_state) {
 207         case HCILL_ASLEEP_TO_AWAKE:
 208                 /*
 209                  * This state means that both the host and the BRF chip
 210                  * have simultaneously sent a wake-up-indication packet.
 211                  * Traditionaly, in this case, receiving a wake-up-indication
 212                  * was enough and an additional wake-up-ack wasn't needed.
 213                  * This has changed with the BRF6350, which does require an
 214                  * explicit wake-up-ack. Other BRF versions, which do not
 215                  * require an explicit ack here, do accept it, thus it is
 216                  * perfectly safe to always send one.
 217                  */
 218                 BT_DBG("dual wake-up-indication");
 219                 /* deliberate fall-through - do not add break */
 220         case HCILL_ASLEEP:
 221                 /* acknowledge device wake up */
 222                 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
 223                         BT_ERR("cannot acknowledge device wake up");
 224                         goto out;
 225                 }
 226                 break;
 227         default:
 228                 /* any other state is illegal */
 229                 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
 230                 break;
 231         }
 232
 233         /* send pending packets and change state to HCILL_AWAKE */
 234         __ll_do_awake(ll);
 235
 236 out:
 237         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 238
 239         /* actually send the packets */
 240         hci_uart_tx_wakeup(hu);
 241 }
 242
 243 /*
 244  * Called upon a sleep-indication from the device
 245  */
 246 static void ll_device_want_to_sleep(struct hci_uart *hu)
 247 {
 248         unsigned long flags;
 249         struct ll_struct *ll = hu->priv;
 250
 251         BT_DBG("hu %p", hu);
 252
 253         /* lock hcill state */
 254         spin_lock_irqsave(&ll->hcill_lock, flags);
 255
 256         /* sanity check */
 257         if (ll->hcill_state != HCILL_AWAKE)
 258                 BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
 259
 260         /* acknowledge device sleep */
 261         if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
 262                 BT_ERR("cannot acknowledge device sleep");
 263                 goto out;
 264         }
 265
 266         /* update state */
 267         ll->hcill_state = HCILL_ASLEEP;
 268
 269 out:
 270         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 271
 272         /* actually send the sleep ack packet */
 273         hci_uart_tx_wakeup(hu);
 274 }
 275
 276 /*
 277  * Called upon wake-up-acknowledgement from the device
 278  */
 279 static void ll_device_woke_up(struct hci_uart *hu)
 280 {
 281         unsigned long flags;
 282         struct ll_struct *ll = hu->priv;
 283
 284         BT_DBG("hu %p", hu);
 285
 286         /* lock hcill state */
 287         spin_lock_irqsave(&ll->hcill_lock, flags);
 288
 289         /* sanity check */
 290         if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
 291                 BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
 292
 293         /* send pending packets and change state to HCILL_AWAKE */
 294         __ll_do_awake(ll);
 295
 296         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 297
 298         /* actually send the packets */
 299         hci_uart_tx_wakeup(hu);
 300 }
 301
 302 /* Enqueue frame for transmittion (padding, crc, etc) */
 303 /* may be called from two simultaneous tasklets */
 304 static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 305 {
 306         unsigned long flags = 0;
 307         struct ll_struct *ll = hu->priv;
 308
 309         BT_DBG("hu %p skb %p", hu, skb);
 310
 311         /* Prepend skb with frame type */
 312         memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
 313
 314         /* lock hcill state */
 315         spin_lock_irqsave(&ll->hcill_lock, flags);
 316
 317         /* act according to current state */
 318         switch (ll->hcill_state) {
 319         case HCILL_AWAKE:
 320                 BT_DBG("device awake, sending normally");
 321                 skb_queue_tail(&ll->txq, skb);
 322                 break;
 323         case HCILL_ASLEEP:
 324                 BT_DBG("device asleep, waking up and queueing packet");
 325                 /* save packet for later */
 326                 skb_queue_tail(&ll->tx_wait_q, skb);
 327                 /* awake device */
 328                 if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
 329                         BT_ERR("cannot wake up device");
 330                         break;
 331                 }
 332                 ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
 333                 break;
 334         case HCILL_ASLEEP_TO_AWAKE:
 335                 BT_DBG("device waking up, queueing packet");
 336                 /* transient state; just keep packet for later */
 337                 skb_queue_tail(&ll->tx_wait_q, skb);
 338                 break;
 339         default:
 340                 BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
 341                 kfree_skb(skb);
 342                 break;
 343         }
 344
 345         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 346
 347         return 0;
 348 }
 349
 350 static inline int ll_check_data_len(struct ll_struct *ll, int len)
 351 {
 352         register int room = skb_tailroom(ll->rx_skb);
 353
 354         BT_DBG("len %d room %d", len, room);
 355
 356         if (!len) {
 357                 hci_recv_frame(ll->rx_skb);
 358         } else if (len > room) {
 359                 BT_ERR("Data length is too large");
 360                 kfree_skb(ll->rx_skb);
 361         } else {
 362                 ll->rx_state = HCILL_W4_DATA;
 363                 ll->rx_count = len;
 364                 return len;
 365         }
 366
 367         ll->rx_state = HCILL_W4_PACKET_TYPE;
 368         ll->rx_skb   = NULL;
 369         ll->rx_count = 0;
 370
 371         return 0;
 372 }
 373
 374 /* Recv data */
 375 static int ll_recv(struct hci_uart *hu, void *data, int count)
 376 {
 377         struct ll_struct *ll = hu->priv;
 378         register char *ptr;
 379         struct hci_event_hdr *eh;
 380         struct hci_acl_hdr   *ah;
 381         struct hci_sco_hdr   *sh;
 382         register int len, type, dlen;
 383
 384         BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
 385
 386         ptr = data;
 387         while (count) {
 388                 if (ll->rx_count) {
 389                         len = min_t(unsigned int, ll->rx_count, count);
 390                         memcpy(skb_put(ll->rx_skb, len), ptr, len);
 391                         ll->rx_count -= len; count -= len; ptr += len;
 392
 393                         if (ll->rx_count)
 394                                 continue;
 395
 396                         switch (ll->rx_state) {
 397                         case HCILL_W4_DATA:
 398                                 BT_DBG("Complete data");
 399                                 hci_recv_frame(ll->rx_skb);
 400
 401                                 ll->rx_state = HCILL_W4_PACKET_TYPE;
 402                                 ll->rx_skb = NULL;
 403                                 continue;
 404
 405                         case HCILL_W4_EVENT_HDR:
 406                                 eh = (struct hci_event_hdr *) ll->rx_skb->data;
 407
 408                                 BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
 409
 410                                 ll_check_data_len(ll, eh->plen);
 411                                 continue;
 412
 413                         case HCILL_W4_ACL_HDR:
 414                                 ah = (struct hci_acl_hdr *) ll->rx_skb->data;
 415                                 dlen = __le16_to_cpu(ah->dlen);
 416
 417                                 BT_DBG("ACL header: dlen %d", dlen);
 418
 419                                 ll_check_data_len(ll, dlen);
 420                                 continue;
 421
 422                         case HCILL_W4_SCO_HDR:
 423                                 sh = (struct hci_sco_hdr *) ll->rx_skb->data;
 424
 425                                 BT_DBG("SCO header: dlen %d", sh->dlen);
 426
 427                                 ll_check_data_len(ll, sh->dlen);
 428                                 continue;
 429                         }
 430                 }
 431
 432                 /* HCILL_W4_PACKET_TYPE */
 433                 switch (*ptr) {
 434                 case HCI_EVENT_PKT:
 435                         BT_DBG("Event packet");
 436                         ll->rx_state = HCILL_W4_EVENT_HDR;
 437                         ll->rx_count = HCI_EVENT_HDR_SIZE;
 438                         type = HCI_EVENT_PKT;
 439                         break;
 440
 441                 case HCI_ACLDATA_PKT:
 442                         BT_DBG("ACL packet");
 443                         ll->rx_state = HCILL_W4_ACL_HDR;
 444                         ll->rx_count = HCI_ACL_HDR_SIZE;
 445                         type = HCI_ACLDATA_PKT;
 446                         break;
 447
 448                 case HCI_SCODATA_PKT:
 449                         BT_DBG("SCO packet");
 450                         ll->rx_state = HCILL_W4_SCO_HDR;
 451                         ll->rx_count = HCI_SCO_HDR_SIZE;
 452                         type = HCI_SCODATA_PKT;
 453                         break;
 454
 455                 /* HCILL signals */
 456                 case HCILL_GO_TO_SLEEP_IND:
 457                         BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
 458                         ll_device_want_to_sleep(hu);
 459                         ptr++; count--;
 460                         continue;
 461
 462                 case HCILL_GO_TO_SLEEP_ACK:
 463                         /* shouldn't happen */
 464                         BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
 465                         ptr++; count--;
 466                         continue;
 467
 468                 case HCILL_WAKE_UP_IND:
 469                         BT_DBG("HCILL_WAKE_UP_IND packet");
 470                         ll_device_want_to_wakeup(hu);
 471                         ptr++; count--;
 472                         continue;
 473
 474                 case HCILL_WAKE_UP_ACK:
 475                         BT_DBG("HCILL_WAKE_UP_ACK packet");
 476                         ll_device_woke_up(hu);
 477                         ptr++; count--;
 478                         continue;
 479
 480                 default:
 481                         BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
 482                         hu->hdev->stat.err_rx++;
 483                         ptr++; count--;
 484                         continue;
 485                 };
 486
 487                 ptr++; count--;
 488
 489                 /* Allocate packet */
 490                 ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
 491                 if (!ll->rx_skb) {
 492                         BT_ERR("Can't allocate mem for new packet");
 493                         ll->rx_state = HCILL_W4_PACKET_TYPE;
 494                         ll->rx_count = 0;
 495                         return 0;
 496                 }
 497
 498                 ll->rx_skb->dev = (void *) hu->hdev;
 499                 bt_cb(ll->rx_skb)->pkt_type = type;
 500         }
 501
 502         return count;
 503 }
 504
 505 static struct sk_buff *ll_dequeue(struct hci_uart *hu)
 506 {
 507         struct ll_struct *ll = hu->priv;
 508         return skb_dequeue(&ll->txq);
 509 }
 510
 511 static struct hci_uart_proto llp = {
 512         .id             = HCI_UART_LL,
 513         .open           = ll_open,
 514         .close          = ll_close,
 515         .recv           = ll_recv,
 516         .enqueue        = ll_enqueue,
 517         .dequeue        = ll_dequeue,
 518         .flush          = ll_flush,
 519 };
 520
 521 int ll_init(void)
 522 {
 523         int err = hci_uart_register_proto(&llp);
 524
 525         if (!err)
 526                 BT_INFO("HCILL protocol initialized");
 527         else
 528                 BT_ERR("HCILL protocol registration failed");
 529
 530         return err;
 531 }
 532
 533 int ll_deinit(void)
 534 {
 535         return hci_uart_unregister_proto(&llp);
 536 }