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