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