drivers/bluetooth/hci_ldisc.c

   1 /*
   2  *
   3  *  Bluetooth HCI UART driver
   4  *
   5  *  Copyright (C) 2000-2001  Qualcomm Incorporated
   6  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
   7  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
   8  *
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or
  13  *  (at your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to the Free Software
  22  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  *
  24  */
  25
  26 #include <linux/module.h>
  27
  28 #include <linux/kernel.h>
  29 #include <linux/init.h>
  30 #include <linux/types.h>
  31 #include <linux/fcntl.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/ptrace.h>
  34 #include <linux/poll.h>
  35
  36 #include <linux/slab.h>
  37 #include <linux/tty.h>
  38 #include <linux/errno.h>
  39 #include <linux/string.h>
  40 #include <linux/signal.h>
  41 #include <linux/ioctl.h>
  42 #include <linux/skbuff.h>
  43
  44 #include <net/bluetooth/bluetooth.h>
  45 #include <net/bluetooth/hci_core.h>
  46
  47 #include "hci_uart.h"
  48
  49 #ifndef CONFIG_BT_HCIUART_DEBUG
  50 #undef  BT_DBG
  51 #define BT_DBG( A... )
  52 #endif
  53
  54 #define VERSION "2.2"
  55
  56 static int reset = 0;
  57
  58 static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
  59
  60 int hci_uart_register_proto(struct hci_uart_proto *p)
  61 {
  62         if (p->id >= HCI_UART_MAX_PROTO)
  63                 return -EINVAL;
  64
  65         if (hup[p->id])
  66                 return -EEXIST;
  67
  68         hup[p->id] = p;
  69
  70         return 0;
  71 }
  72
  73 int hci_uart_unregister_proto(struct hci_uart_proto *p)
  74 {
  75         if (p->id >= HCI_UART_MAX_PROTO)
  76                 return -EINVAL;
  77
  78         if (!hup[p->id])
  79                 return -EINVAL;
  80
  81         hup[p->id] = NULL;
  82
  83         return 0;
  84 }
  85
  86 static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
  87 {
  88         if (id >= HCI_UART_MAX_PROTO)
  89                 return NULL;
  90
  91         return hup[id];
  92 }
  93
  94 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
  95 {
  96         struct hci_dev *hdev = hu->hdev;
  97
  98         /* Update HCI stat counters */
  99         switch (pkt_type) {
 100         case HCI_COMMAND_PKT:
 101                 hdev->stat.cmd_tx++;
 102                 break;
 103
 104         case HCI_ACLDATA_PKT:
 105                 hdev->stat.acl_tx++;
 106                 break;
 107
 108         case HCI_SCODATA_PKT:
 109                 hdev->stat.cmd_tx++;
 110                 break;
 111         }
 112 }
 113
 114 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
 115 {
 116         struct sk_buff *skb = hu->tx_skb;
 117
 118         if (!skb)
 119                 skb = hu->proto->dequeue(hu);
 120         else
 121                 hu->tx_skb = NULL;
 122
 123         return skb;
 124 }
 125
 126 int hci_uart_tx_wakeup(struct hci_uart *hu)
 127 {
 128         struct tty_struct *tty = hu->tty;
 129         struct hci_dev *hdev = hu->hdev;
 130         struct sk_buff *skb;
 131
 132         if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
 133                 set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 134                 return 0;
 135         }
 136
 137         BT_DBG("");
 138
 139 restart:
 140         clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 141
 142         while ((skb = hci_uart_dequeue(hu))) {
 143                 int len;
 144
 145                 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 146                 len = tty->ops->write(tty, skb->data, skb->len);
 147                 hdev->stat.byte_tx += len;
 148
 149                 skb_pull(skb, len);
 150                 if (skb->len) {
 151                         hu->tx_skb = skb;
 152                         break;
 153                 }
 154
 155                 hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
 156                 kfree_skb(skb);
 157         }
 158
 159         if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
 160                 goto restart;
 161
 162         clear_bit(HCI_UART_SENDING, &hu->tx_state);
 163         return 0;
 164 }
 165
 166 /* ------- Interface to HCI layer ------ */
 167 /* Initialize device */
 168 static int hci_uart_open(struct hci_dev *hdev)
 169 {
 170         BT_DBG("%s %p", hdev->name, hdev);
 171
 172         /* Nothing to do for UART driver */
 173
 174         set_bit(HCI_RUNNING, &hdev->flags);
 175
 176         return 0;
 177 }
 178
 179 /* Reset device */
 180 static int hci_uart_flush(struct hci_dev *hdev)
 181 {
 182         struct hci_uart *hu  = (struct hci_uart *) hdev->driver_data;
 183         struct tty_struct *tty = hu->tty;
 184
 185         BT_DBG("hdev %p tty %p", hdev, tty);
 186
 187         if (hu->tx_skb) {
 188                 kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 189         }
 190
 191         /* Flush any pending characters in the driver and discipline. */
 192         tty_ldisc_flush(tty);
 193         tty_driver_flush_buffer(tty);
 194
 195         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 196                 hu->proto->flush(hu);
 197
 198         return 0;
 199 }
 200
 201 /* Close device */
 202 static int hci_uart_close(struct hci_dev *hdev)
 203 {
 204         BT_DBG("hdev %p", hdev);
 205
 206         if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
 207                 return 0;
 208
 209         hci_uart_flush(hdev);
 210         hdev->flush = NULL;
 211         return 0;
 212 }
 213
 214 /* Send frames from HCI layer */
 215 static int hci_uart_send_frame(struct sk_buff *skb)
 216 {
 217         struct hci_dev* hdev = (struct hci_dev *) skb->dev;
 218         struct tty_struct *tty;
 219         struct hci_uart *hu;
 220
 221         if (!hdev) {
 222                 BT_ERR("Frame for uknown device (hdev=NULL)");
 223                 return -ENODEV;
 224         }
 225
 226         if (!test_bit(HCI_RUNNING, &hdev->flags))
 227                 return -EBUSY;
 228
 229         hu = (struct hci_uart *) hdev->driver_data;
 230         tty = hu->tty;
 231
 232         BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
 233
 234         hu->proto->enqueue(hu, skb);
 235
 236         hci_uart_tx_wakeup(hu);
 237
 238         return 0;
 239 }
 240
 241 static void hci_uart_destruct(struct hci_dev *hdev)
 242 {
 243         if (!hdev)
 244                 return;
 245
 246         BT_DBG("%s", hdev->name);
 247         kfree(hdev->driver_data);
 248 }
 249
 250 /* ------ LDISC part ------ */
 251 /* hci_uart_tty_open
 252  *
 253  *     Called when line discipline changed to HCI_UART.
 254  *
 255  * Arguments:
 256  *     tty    pointer to tty info structure
 257  * Return Value:
 258  *     0 if success, otherwise error code
 259  */
 260 static int hci_uart_tty_open(struct tty_struct *tty)
 261 {
 262         struct hci_uart *hu = (void *) tty->disc_data;
 263
 264         BT_DBG("tty %p", tty);
 265
 266         if (hu)
 267                 return -EEXIST;
 268
 269         if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
 270                 BT_ERR("Can't allocate control structure");
 271                 return -ENFILE;
 272         }
 273
 274         tty->disc_data = hu;
 275         hu->tty = tty;
 276         tty->receive_room = 65536;
 277
 278         spin_lock_init(&hu->rx_lock);
 279
 280         /* Flush any pending characters in the driver and line discipline. */
 281
 282         /* FIXME: why is this needed. Note don't use ldisc_ref here as the
 283            open path is before the ldisc is referencable */
 284
 285         if (tty->ldisc.ops->flush_buffer)
 286                 tty->ldisc.ops->flush_buffer(tty);
 287         tty_driver_flush_buffer(tty);
 288
 289         return 0;
 290 }
 291
 292 /* hci_uart_tty_close()
 293  *
 294  *    Called when the line discipline is changed to something
 295  *    else, the tty is closed, or the tty detects a hangup.
 296  */
 297 static void hci_uart_tty_close(struct tty_struct *tty)
 298 {
 299         struct hci_uart *hu = (void *)tty->disc_data;
 300
 301         BT_DBG("tty %p", tty);
 302
 303         /* Detach from the tty */
 304         tty->disc_data = NULL;
 305
 306         if (hu) {
 307                 struct hci_dev *hdev = hu->hdev;
 308
 309                 if (hdev)
 310                         hci_uart_close(hdev);
 311
 312                 if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 313                         hu->proto->close(hu);
 314                         hci_unregister_dev(hdev);
 315                         hci_free_dev(hdev);
 316                 }
 317         }
 318 }
 319
 320 /* hci_uart_tty_wakeup()
 321  *
 322  *    Callback for transmit wakeup. Called when low level
 323  *    device driver can accept more send data.
 324  *
 325  * Arguments:        tty    pointer to associated tty instance data
 326  * Return Value:    None
 327  */
 328 static void hci_uart_tty_wakeup(struct tty_struct *tty)
 329 {
 330         struct hci_uart *hu = (void *)tty->disc_data;
 331
 332         BT_DBG("");
 333
 334         if (!hu)
 335                 return;
 336
 337         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 338
 339         if (tty != hu->tty)
 340                 return;
 341
 342         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 343                 hci_uart_tx_wakeup(hu);
 344 }
 345
 346 /* hci_uart_tty_receive()
 347  *
 348  *     Called by tty low level driver when receive data is
 349  *     available.
 350  *
 351  * Arguments:  tty          pointer to tty isntance data
 352  *             data         pointer to received data
 353  *             flags        pointer to flags for data
 354  *             count        count of received data in bytes
 355  *
 356  * Return Value:    None
 357  */
 358 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
 359 {
 360         struct hci_uart *hu = (void *)tty->disc_data;
 361
 362         if (!hu || tty != hu->tty)
 363                 return;
 364
 365         if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
 366                 return;
 367
 368         spin_lock(&hu->rx_lock);
 369         hu->proto->recv(hu, (void *) data, count);
 370         hu->hdev->stat.byte_rx += count;
 371         spin_unlock(&hu->rx_lock);
 372
 373         tty_unthrottle(tty);
 374 }
 375
 376 static int hci_uart_register_dev(struct hci_uart *hu)
 377 {
 378         struct hci_dev *hdev;
 379
 380         BT_DBG("");
 381
 382         /* Initialize and register HCI device */
 383         hdev = hci_alloc_dev();
 384         if (!hdev) {
 385                 BT_ERR("Can't allocate HCI device");
 386                 return -ENOMEM;
 387         }
 388
 389         hu->hdev = hdev;
 390
 391         hdev->type = HCI_UART;
 392         hdev->driver_data = hu;
 393
 394         hdev->open  = hci_uart_open;
 395         hdev->close = hci_uart_close;
 396         hdev->flush = hci_uart_flush;
 397         hdev->send  = hci_uart_send_frame;
 398         hdev->destruct = hci_uart_destruct;
 399
 400         hdev->owner = THIS_MODULE;
 401
 402         if (reset)
 403                 set_bit(HCI_QUIRK_RESET_ON_INIT, &hdev->quirks);
 404
 405         if (hci_register_dev(hdev) < 0) {
 406                 BT_ERR("Can't register HCI device");
 407                 hci_free_dev(hdev);
 408                 return -ENODEV;
 409         }
 410
 411         return 0;
 412 }
 413
 414 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 415 {
 416         struct hci_uart_proto *p;
 417         int err;
 418
 419         p = hci_uart_get_proto(id);
 420         if (!p)
 421                 return -EPROTONOSUPPORT;
 422
 423         err = p->open(hu);
 424         if (err)
 425                 return err;
 426
 427         hu->proto = p;
 428
 429         err = hci_uart_register_dev(hu);
 430         if (err) {
 431                 p->close(hu);
 432                 return err;
 433         }
 434
 435         return 0;
 436 }
 437
 438 /* hci_uart_tty_ioctl()
 439  *
 440  *    Process IOCTL system call for the tty device.
 441  *
 442  * Arguments:
 443  *
 444  *    tty        pointer to tty instance data
 445  *    file       pointer to open file object for device
 446  *    cmd        IOCTL command code
 447  *    arg        argument for IOCTL call (cmd dependent)
 448  *
 449  * Return Value:    Command dependent
 450  */
 451 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 452                                         unsigned int cmd, unsigned long arg)
 453 {
 454         struct hci_uart *hu = (void *)tty->disc_data;
 455         int err = 0;
 456
 457         BT_DBG("");
 458
 459         /* Verify the status of the device */
 460         if (!hu)
 461                 return -EBADF;
 462
 463         switch (cmd) {
 464         case HCIUARTSETPROTO:
 465                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 466                         err = hci_uart_set_proto(hu, arg);
 467                         if (err) {
 468                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 469                                 return err;
 470                         }
 471                         tty->low_latency = 1;
 472                 } else
 473                         return -EBUSY;
 474                 break;
 475
 476         case HCIUARTGETPROTO:
 477                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 478                         return hu->proto->id;
 479                 return -EUNATCH;
 480
 481         case HCIUARTGETDEVICE:
 482                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 483                         return hu->hdev->id;
 484                 return -EUNATCH;
 485
 486         default:
 487                 err = n_tty_ioctl(tty, file, cmd, arg);
 488                 break;
 489         };
 490
 491         return err;
 492 }
 493
 494 /*
 495  * We don't provide read/write/poll interface for user space.
 496  */
 497 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 498                                         unsigned char __user *buf, size_t nr)
 499 {
 500         return 0;
 501 }
 502
 503 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 504                                         const unsigned char *data, size_t count)
 505 {
 506         return 0;
 507 }
 508
 509 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 510                                         struct file *filp, poll_table *wait)
 511 {
 512         return 0;
 513 }
 514
 515 static int __init hci_uart_init(void)
 516 {
 517         static struct tty_ldisc_ops hci_uart_ldisc;
 518         int err;
 519
 520         BT_INFO("HCI UART driver ver %s", VERSION);
 521
 522         /* Register the tty discipline */
 523
 524         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 525         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 526         hci_uart_ldisc.name             = "n_hci";
 527         hci_uart_ldisc.open             = hci_uart_tty_open;
 528         hci_uart_ldisc.close            = hci_uart_tty_close;
 529         hci_uart_ldisc.read             = hci_uart_tty_read;
 530         hci_uart_ldisc.write            = hci_uart_tty_write;
 531         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 532         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 533         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 534         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 535         hci_uart_ldisc.owner            = THIS_MODULE;
 536
 537         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 538                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 539                 return err;
 540         }
 541
 542 #ifdef CONFIG_BT_HCIUART_H4
 543         h4_init();
 544 #endif
 545 #ifdef CONFIG_BT_HCIUART_BCSP
 546         bcsp_init();
 547 #endif
 548 #ifdef CONFIG_BT_HCIUART_LL
 549         ll_init();
 550 #endif
 551
 552         return 0;
 553 }
 554
 555 static void __exit hci_uart_exit(void)
 556 {
 557         int err;
 558
 559 #ifdef CONFIG_BT_HCIUART_H4
 560         h4_deinit();
 561 #endif
 562 #ifdef CONFIG_BT_HCIUART_BCSP
 563         bcsp_deinit();
 564 #endif
 565 #ifdef CONFIG_BT_HCIUART_LL
 566         ll_deinit();
 567 #endif
 568
 569         /* Release tty registration of line discipline */
 570         if ((err = tty_unregister_ldisc(N_HCI)))
 571                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 572 }
 573
 574 module_init(hci_uart_init);
 575 module_exit(hci_uart_exit);
 576
 577 module_param(reset, bool, 0644);
 578 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 579
 580 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
 581 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 582 MODULE_VERSION(VERSION);
 583 MODULE_LICENSE("GPL");
 584 MODULE_ALIAS_LDISC(N_HCI);