Pileus Git - ~andy/linux/blob - 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 #ifndef CONFIG_BT_HCIUART_DEBUG
  55 #undef  BT_DBG
  56 #define BT_DBG( A... )
  57 #endif
  58
  59 /* HCILL commands */
  60 #define HCILL_GO_TO_SLEEP_IND   0x30
  61 #define HCILL_GO_TO_SLEEP_ACK   0x31
  62 #define HCILL_WAKE_UP_IND       0x32
  63 #define HCILL_WAKE_UP_ACK       0x33
  64
  65 /* HCILL receiver States */
  66 #define HCILL_W4_PACKET_TYPE    0
  67 #define HCILL_W4_EVENT_HDR      1
  68 #define HCILL_W4_ACL_HDR        2
  69 #define HCILL_W4_SCO_HDR        3
  70 #define HCILL_W4_DATA           4
  71
  72 /* HCILL states */
  73 enum hcill_states_e {
  74         HCILL_ASLEEP,
  75         HCILL_ASLEEP_TO_AWAKE,
  76         HCILL_AWAKE,
  77         HCILL_AWAKE_TO_ASLEEP
  78 };
  79
  80 struct hcill_cmd {
  81         u8 cmd;
  82 } __attribute__((packed));
  83
  84 struct ll_struct {
  85         unsigned long rx_state;
  86         unsigned long rx_count;
  87         struct sk_buff *rx_skb;
  88         struct sk_buff_head txq;
  89         spinlock_t hcill_lock;          /* HCILL state lock     */
  90         unsigned long hcill_state;      /* HCILL power state    */
  91         struct sk_buff_head tx_wait_q;  /* HCILL wait queue     */
  92 };
  93
  94 /*
  95  * Builds and sends an HCILL command packet.
  96  * These are very simple packets with only 1 cmd byte
  97  */
  98 static int send_hcill_cmd(u8 cmd, struct hci_uart *hu)
  99 {
 100         int err = 0;
 101         struct sk_buff *skb = NULL;
 102         struct ll_struct *ll = hu->priv;
 103         struct hcill_cmd *hcill_packet;
 104
 105         BT_DBG("hu %p cmd 0x%x", hu, cmd);
 106
 107         /* allocate packet */
 108         skb = bt_skb_alloc(1, GFP_ATOMIC);
 109         if (!skb) {
 110                 BT_ERR("cannot allocate memory for HCILL packet");
 111                 err = -ENOMEM;
 112                 goto out;
 113         }
 114
 115         /* prepare packet */
 116         hcill_packet = (struct hcill_cmd *) skb_put(skb, 1);
 117         hcill_packet->cmd = cmd;
 118         skb->dev = (void *) hu->hdev;
 119
 120         /* send packet */
 121         skb_queue_tail(&ll->txq, skb);
 122 out:
 123         return err;
 124 }
 125
 126 /* Initialize protocol */
 127 static int ll_open(struct hci_uart *hu)
 128 {
 129         struct ll_struct *ll;
 130
 131         BT_DBG("hu %p", hu);
 132
 133         ll = kzalloc(sizeof(*ll), GFP_ATOMIC);
 134         if (!ll)
 135                 return -ENOMEM;
 136
 137         skb_queue_head_init(&ll->txq);
 138         skb_queue_head_init(&ll->tx_wait_q);
 139         spin_lock_init(&ll->hcill_lock);
 140
 141         ll->hcill_state = HCILL_AWAKE;
 142
 143         hu->priv = ll;
 144
 145         return 0;
 146 }
 147
 148 /* Flush protocol data */
 149 static int ll_flush(struct hci_uart *hu)
 150 {
 151         struct ll_struct *ll = hu->priv;
 152
 153         BT_DBG("hu %p", hu);
 154
 155         skb_queue_purge(&ll->tx_wait_q);
 156         skb_queue_purge(&ll->txq);
 157
 158         return 0;
 159 }
 160
 161 /* Close protocol */
 162 static int ll_close(struct hci_uart *hu)
 163 {
 164         struct ll_struct *ll = hu->priv;
 165
 166         BT_DBG("hu %p", hu);
 167
 168         skb_queue_purge(&ll->tx_wait_q);
 169         skb_queue_purge(&ll->txq);
 170
 171         if (ll->rx_skb)
 172                 kfree_skb(ll->rx_skb);
 173
 174         hu->priv = NULL;
 175
 176         kfree(ll);
 177
 178         return 0;
 179 }
 180
 181 /*
 182  * internal function, which does common work of the device wake up process:
 183  * 1. places all pending packets (waiting in tx_wait_q list) in txq list.
 184  * 2. changes internal state to HCILL_AWAKE.
 185  * Note: assumes that hcill_lock spinlock is taken,
 186  * shouldn't be called otherwise!
 187  */
 188 static void __ll_do_awake(struct ll_struct *ll)
 189 {
 190         struct sk_buff *skb = NULL;
 191
 192         while ((skb = skb_dequeue(&ll->tx_wait_q)))
 193                 skb_queue_tail(&ll->txq, skb);
 194
 195         ll->hcill_state = HCILL_AWAKE;
 196 }
 197
 198 /*
 199  * Called upon a wake-up-indication from the device
 200  */
 201 static void ll_device_want_to_wakeup(struct hci_uart *hu)
 202 {
 203         unsigned long flags;
 204         struct ll_struct *ll = hu->priv;
 205
 206         BT_DBG("hu %p", hu);
 207
 208         /* lock hcill state */
 209         spin_lock_irqsave(&ll->hcill_lock, flags);
 210
 211         switch (ll->hcill_state) {
 212         case HCILL_ASLEEP_TO_AWAKE:
 213                 /*
 214                  * This state means that both the host and the BRF chip
 215                  * have simultaneously sent a wake-up-indication packet.
 216                  * Traditionaly, in this case, receiving a wake-up-indication
 217                  * was enough and an additional wake-up-ack wasn't needed.
 218                  * This has changed with the BRF6350, which does require an
 219                  * explicit wake-up-ack. Other BRF versions, which do not
 220                  * require an explicit ack here, do accept it, thus it is
 221                  * perfectly safe to always send one.
 222                  */
 223                 BT_DBG("dual wake-up-indication");
 224                 /* deliberate fall-through - do not add break */
 225         case HCILL_ASLEEP:
 226                 /* acknowledge device wake up */
 227                 if (send_hcill_cmd(HCILL_WAKE_UP_ACK, hu) < 0) {
 228                         BT_ERR("cannot acknowledge device wake up");
 229                         goto out;
 230                 }
 231                 break;
 232         default:
 233                 /* any other state is illegal */
 234                 BT_ERR("received HCILL_WAKE_UP_IND in state %ld", ll->hcill_state);
 235                 break;
 236         }
 237
 238         /* send pending packets and change state to HCILL_AWAKE */
 239         __ll_do_awake(ll);
 240
 241 out:
 242         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 243
 244         /* actually send the packets */
 245         hci_uart_tx_wakeup(hu);
 246 }
 247
 248 /*
 249  * Called upon a sleep-indication from the device
 250  */
 251 static void ll_device_want_to_sleep(struct hci_uart *hu)
 252 {
 253         unsigned long flags;
 254         struct ll_struct *ll = hu->priv;
 255
 256         BT_DBG("hu %p", hu);
 257
 258         /* lock hcill state */
 259         spin_lock_irqsave(&ll->hcill_lock, flags);
 260
 261         /* sanity check */
 262         if (ll->hcill_state != HCILL_AWAKE)
 263                 BT_ERR("ERR: HCILL_GO_TO_SLEEP_IND in state %ld", ll->hcill_state);
 264
 265         /* acknowledge device sleep */
 266         if (send_hcill_cmd(HCILL_GO_TO_SLEEP_ACK, hu) < 0) {
 267                 BT_ERR("cannot acknowledge device sleep");
 268                 goto out;
 269         }
 270
 271         /* update state */
 272         ll->hcill_state = HCILL_ASLEEP;
 273
 274 out:
 275         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 276
 277         /* actually send the sleep ack packet */
 278         hci_uart_tx_wakeup(hu);
 279 }
 280
 281 /*
 282  * Called upon wake-up-acknowledgement from the device
 283  */
 284 static void ll_device_woke_up(struct hci_uart *hu)
 285 {
 286         unsigned long flags;
 287         struct ll_struct *ll = hu->priv;
 288
 289         BT_DBG("hu %p", hu);
 290
 291         /* lock hcill state */
 292         spin_lock_irqsave(&ll->hcill_lock, flags);
 293
 294         /* sanity check */
 295         if (ll->hcill_state != HCILL_ASLEEP_TO_AWAKE)
 296                 BT_ERR("received HCILL_WAKE_UP_ACK in state %ld", ll->hcill_state);
 297
 298         /* send pending packets and change state to HCILL_AWAKE */
 299         __ll_do_awake(ll);
 300
 301         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 302
 303         /* actually send the packets */
 304         hci_uart_tx_wakeup(hu);
 305 }
 306
 307 /* Enqueue frame for transmittion (padding, crc, etc) */
 308 /* may be called from two simultaneous tasklets */
 309 static int ll_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 310 {
 311         unsigned long flags = 0;
 312         struct ll_struct *ll = hu->priv;
 313
 314         BT_DBG("hu %p skb %p", hu, skb);
 315
 316         /* Prepend skb with frame type */
 317         memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
 318
 319         /* lock hcill state */
 320         spin_lock_irqsave(&ll->hcill_lock, flags);
 321
 322         /* act according to current state */
 323         switch (ll->hcill_state) {
 324         case HCILL_AWAKE:
 325                 BT_DBG("device awake, sending normally");
 326                 skb_queue_tail(&ll->txq, skb);
 327                 break;
 328         case HCILL_ASLEEP:
 329                 BT_DBG("device asleep, waking up and queueing packet");
 330                 /* save packet for later */
 331                 skb_queue_tail(&ll->tx_wait_q, skb);
 332                 /* awake device */
 333                 if (send_hcill_cmd(HCILL_WAKE_UP_IND, hu) < 0) {
 334                         BT_ERR("cannot wake up device");
 335                         break;
 336                 }
 337                 ll->hcill_state = HCILL_ASLEEP_TO_AWAKE;
 338                 break;
 339         case HCILL_ASLEEP_TO_AWAKE:
 340                 BT_DBG("device waking up, queueing packet");
 341                 /* transient state; just keep packet for later */
 342                 skb_queue_tail(&ll->tx_wait_q, skb);
 343                 break;
 344         default:
 345                 BT_ERR("illegal hcill state: %ld (losing packet)", ll->hcill_state);
 346                 kfree_skb(skb);
 347                 break;
 348         }
 349
 350         spin_unlock_irqrestore(&ll->hcill_lock, flags);
 351
 352         return 0;
 353 }
 354
 355 static inline int ll_check_data_len(struct ll_struct *ll, int len)
 356 {
 357         register int room = skb_tailroom(ll->rx_skb);
 358
 359         BT_DBG("len %d room %d", len, room);
 360
 361         if (!len) {
 362                 hci_recv_frame(ll->rx_skb);
 363         } else if (len > room) {
 364                 BT_ERR("Data length is too large");
 365                 kfree_skb(ll->rx_skb);
 366         } else {
 367                 ll->rx_state = HCILL_W4_DATA;
 368                 ll->rx_count = len;
 369                 return len;
 370         }
 371
 372         ll->rx_state = HCILL_W4_PACKET_TYPE;
 373         ll->rx_skb   = NULL;
 374         ll->rx_count = 0;
 375
 376         return 0;
 377 }
 378
 379 /* Recv data */
 380 static int ll_recv(struct hci_uart *hu, void *data, int count)
 381 {
 382         struct ll_struct *ll = hu->priv;
 383         register char *ptr;
 384         struct hci_event_hdr *eh;
 385         struct hci_acl_hdr   *ah;
 386         struct hci_sco_hdr   *sh;
 387         register int len, type, dlen;
 388
 389         BT_DBG("hu %p count %d rx_state %ld rx_count %ld", hu, count, ll->rx_state, ll->rx_count);
 390
 391         ptr = data;
 392         while (count) {
 393                 if (ll->rx_count) {
 394                         len = min_t(unsigned int, ll->rx_count, count);
 395                         memcpy(skb_put(ll->rx_skb, len), ptr, len);
 396                         ll->rx_count -= len; count -= len; ptr += len;
 397
 398                         if (ll->rx_count)
 399                                 continue;
 400
 401                         switch (ll->rx_state) {
 402                         case HCILL_W4_DATA:
 403                                 BT_DBG("Complete data");
 404                                 hci_recv_frame(ll->rx_skb);
 405
 406                                 ll->rx_state = HCILL_W4_PACKET_TYPE;
 407                                 ll->rx_skb = NULL;
 408                                 continue;
 409
 410                         case HCILL_W4_EVENT_HDR:
 411                                 eh = (struct hci_event_hdr *) ll->rx_skb->data;
 412
 413                                 BT_DBG("Event header: evt 0x%2.2x plen %d", eh->evt, eh->plen);
 414
 415                                 ll_check_data_len(ll, eh->plen);
 416                                 continue;
 417
 418                         case HCILL_W4_ACL_HDR:
 419                                 ah = (struct hci_acl_hdr *) ll->rx_skb->data;
 420                                 dlen = __le16_to_cpu(ah->dlen);
 421
 422                                 BT_DBG("ACL header: dlen %d", dlen);
 423
 424                                 ll_check_data_len(ll, dlen);
 425                                 continue;
 426
 427                         case HCILL_W4_SCO_HDR:
 428                                 sh = (struct hci_sco_hdr *) ll->rx_skb->data;
 429
 430                                 BT_DBG("SCO header: dlen %d", sh->dlen);
 431
 432                                 ll_check_data_len(ll, sh->dlen);
 433                                 continue;
 434                         }
 435                 }
 436
 437                 /* HCILL_W4_PACKET_TYPE */
 438                 switch (*ptr) {
 439                 case HCI_EVENT_PKT:
 440                         BT_DBG("Event packet");
 441                         ll->rx_state = HCILL_W4_EVENT_HDR;
 442                         ll->rx_count = HCI_EVENT_HDR_SIZE;
 443                         type = HCI_EVENT_PKT;
 444                         break;
 445
 446                 case HCI_ACLDATA_PKT:
 447                         BT_DBG("ACL packet");
 448                         ll->rx_state = HCILL_W4_ACL_HDR;
 449                         ll->rx_count = HCI_ACL_HDR_SIZE;
 450                         type = HCI_ACLDATA_PKT;
 451                         break;
 452
 453                 case HCI_SCODATA_PKT:
 454                         BT_DBG("SCO packet");
 455                         ll->rx_state = HCILL_W4_SCO_HDR;
 456                         ll->rx_count = HCI_SCO_HDR_SIZE;
 457                         type = HCI_SCODATA_PKT;
 458                         break;
 459
 460                 /* HCILL signals */
 461                 case HCILL_GO_TO_SLEEP_IND:
 462                         BT_DBG("HCILL_GO_TO_SLEEP_IND packet");
 463                         ll_device_want_to_sleep(hu);
 464                         ptr++; count--;
 465                         continue;
 466
 467                 case HCILL_GO_TO_SLEEP_ACK:
 468                         /* shouldn't happen */
 469                         BT_ERR("received HCILL_GO_TO_SLEEP_ACK (in state %ld)", ll->hcill_state);
 470                         ptr++; count--;
 471                         continue;
 472
 473                 case HCILL_WAKE_UP_IND:
 474                         BT_DBG("HCILL_WAKE_UP_IND packet");
 475                         ll_device_want_to_wakeup(hu);
 476                         ptr++; count--;
 477                         continue;
 478
 479                 case HCILL_WAKE_UP_ACK:
 480                         BT_DBG("HCILL_WAKE_UP_ACK packet");
 481                         ll_device_woke_up(hu);
 482                         ptr++; count--;
 483                         continue;
 484
 485                 default:
 486                         BT_ERR("Unknown HCI packet type %2.2x", (__u8)*ptr);
 487                         hu->hdev->stat.err_rx++;
 488                         ptr++; count--;
 489                         continue;
 490                 };
 491
 492                 ptr++; count--;
 493
 494                 /* Allocate packet */
 495                 ll->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC);
 496                 if (!ll->rx_skb) {
 497                         BT_ERR("Can't allocate mem for new packet");
 498                         ll->rx_state = HCILL_W4_PACKET_TYPE;
 499                         ll->rx_count = 0;
 500                         return 0;
 501                 }
 502
 503                 ll->rx_skb->dev = (void *) hu->hdev;
 504                 bt_cb(ll->rx_skb)->pkt_type = type;
 505         }
 506
 507         return count;
 508 }
 509
 510 static struct sk_buff *ll_dequeue(struct hci_uart *hu)
 511 {
 512         struct ll_struct *ll = hu->priv;
 513         return skb_dequeue(&ll->txq);
 514 }
 515
 516 static struct hci_uart_proto llp = {
 517         .id             = HCI_UART_LL,
 518         .open           = ll_open,
 519         .close          = ll_close,
 520         .recv           = ll_recv,
 521         .enqueue        = ll_enqueue,
 522         .dequeue        = ll_dequeue,
 523         .flush          = ll_flush,
 524 };
 525
 526 int ll_init(void)
 527 {
 528         int err = hci_uart_register_proto(&llp);
 529
 530         if (!err)
 531                 BT_INFO("HCILL protocol initialized");
 532         else
 533                 BT_ERR("HCILL protocol registration failed");
 534
 535         return err;
 536 }
 537
 538 int ll_deinit(void)
 539 {
 540         return hci_uart_unregister_proto(&llp);
 541 }