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 #define VERSION "2.2"
  50
  51 static int reset = 0;
  52
  53 static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
  54
  55 int hci_uart_register_proto(struct hci_uart_proto *p)
  56 {
  57         if (p->id >= HCI_UART_MAX_PROTO)
  58                 return -EINVAL;
  59
  60         if (hup[p->id])
  61                 return -EEXIST;
  62
  63         hup[p->id] = p;
  64
  65         return 0;
  66 }
  67
  68 int hci_uart_unregister_proto(struct hci_uart_proto *p)
  69 {
  70         if (p->id >= HCI_UART_MAX_PROTO)
  71                 return -EINVAL;
  72
  73         if (!hup[p->id])
  74                 return -EINVAL;
  75
  76         hup[p->id] = NULL;
  77
  78         return 0;
  79 }
  80
  81 static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
  82 {
  83         if (id >= HCI_UART_MAX_PROTO)
  84                 return NULL;
  85
  86         return hup[id];
  87 }
  88
  89 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
  90 {
  91         struct hci_dev *hdev = hu->hdev;
  92
  93         /* Update HCI stat counters */
  94         switch (pkt_type) {
  95         case HCI_COMMAND_PKT:
  96                 hdev->stat.cmd_tx++;
  97                 break;
  98
  99         case HCI_ACLDATA_PKT:
 100                 hdev->stat.acl_tx++;
 101                 break;
 102
 103         case HCI_SCODATA_PKT:
 104                 hdev->stat.sco_tx++;
 105                 break;
 106         }
 107 }
 108
 109 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
 110 {
 111         struct sk_buff *skb = hu->tx_skb;
 112
 113         if (!skb)
 114                 skb = hu->proto->dequeue(hu);
 115         else
 116                 hu->tx_skb = NULL;
 117
 118         return skb;
 119 }
 120
 121 int hci_uart_tx_wakeup(struct hci_uart *hu)
 122 {
 123         if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
 124                 set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 125                 return 0;
 126         }
 127
 128         BT_DBG("");
 129
 130         schedule_work(&hu->write_work);
 131
 132         return 0;
 133 }
 134
 135 static void hci_uart_write_work(struct work_struct *work)
 136 {
 137         struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
 138         struct tty_struct *tty = hu->tty;
 139         struct hci_dev *hdev = hu->hdev;
 140         struct sk_buff *skb;
 141
 142         /* REVISIT: should we cope with bad skbs or ->write() returning
 143          * and error value ?
 144          */
 145
 146 restart:
 147         clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 148
 149         while ((skb = hci_uart_dequeue(hu))) {
 150                 int len;
 151
 152                 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 153                 len = tty->ops->write(tty, skb->data, skb->len);
 154                 hdev->stat.byte_tx += len;
 155
 156                 skb_pull(skb, len);
 157                 if (skb->len) {
 158                         hu->tx_skb = skb;
 159                         break;
 160                 }
 161
 162                 hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
 163                 kfree_skb(skb);
 164         }
 165
 166         if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
 167                 goto restart;
 168
 169         clear_bit(HCI_UART_SENDING, &hu->tx_state);
 170 }
 171
 172 /* ------- Interface to HCI layer ------ */
 173 /* Initialize device */
 174 static int hci_uart_open(struct hci_dev *hdev)
 175 {
 176         BT_DBG("%s %p", hdev->name, hdev);
 177
 178         /* Nothing to do for UART driver */
 179
 180         set_bit(HCI_RUNNING, &hdev->flags);
 181
 182         return 0;
 183 }
 184
 185 /* Reset device */
 186 static int hci_uart_flush(struct hci_dev *hdev)
 187 {
 188         struct hci_uart *hu  = (struct hci_uart *) hdev->driver_data;
 189         struct tty_struct *tty = hu->tty;
 190
 191         BT_DBG("hdev %p tty %p", hdev, tty);
 192
 193         if (hu->tx_skb) {
 194                 kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 195         }
 196
 197         /* Flush any pending characters in the driver and discipline. */
 198         tty_ldisc_flush(tty);
 199         tty_driver_flush_buffer(tty);
 200
 201         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 202                 hu->proto->flush(hu);
 203
 204         return 0;
 205 }
 206
 207 /* Close device */
 208 static int hci_uart_close(struct hci_dev *hdev)
 209 {
 210         BT_DBG("hdev %p", hdev);
 211
 212         if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
 213                 return 0;
 214
 215         hci_uart_flush(hdev);
 216         hdev->flush = NULL;
 217         return 0;
 218 }
 219
 220 /* Send frames from HCI layer */
 221 static int hci_uart_send_frame(struct sk_buff *skb)
 222 {
 223         struct hci_dev* hdev = (struct hci_dev *) skb->dev;
 224         struct hci_uart *hu;
 225
 226         if (!hdev) {
 227                 BT_ERR("Frame for unknown device (hdev=NULL)");
 228                 return -ENODEV;
 229         }
 230
 231         if (!test_bit(HCI_RUNNING, &hdev->flags))
 232                 return -EBUSY;
 233
 234         hu = (struct hci_uart *) hdev->driver_data;
 235
 236         BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
 237
 238         hu->proto->enqueue(hu, skb);
 239
 240         hci_uart_tx_wakeup(hu);
 241
 242         return 0;
 243 }
 244
 245 static void hci_uart_destruct(struct hci_dev *hdev)
 246 {
 247         if (!hdev)
 248                 return;
 249
 250         BT_DBG("%s", hdev->name);
 251 }
 252
 253 /* ------ LDISC part ------ */
 254 /* hci_uart_tty_open
 255  *
 256  *     Called when line discipline changed to HCI_UART.
 257  *
 258  * Arguments:
 259  *     tty    pointer to tty info structure
 260  * Return Value:
 261  *     0 if success, otherwise error code
 262  */
 263 static int hci_uart_tty_open(struct tty_struct *tty)
 264 {
 265         struct hci_uart *hu = (void *) tty->disc_data;
 266
 267         BT_DBG("tty %p", tty);
 268
 269         /* FIXME: This btw is bogus, nothing requires the old ldisc to clear
 270            the pointer */
 271         if (hu)
 272                 return -EEXIST;
 273
 274         /* Error if the tty has no write op instead of leaving an exploitable
 275            hole */
 276         if (tty->ops->write == NULL)
 277                 return -EOPNOTSUPP;
 278
 279         if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
 280                 BT_ERR("Can't allocate control structure");
 281                 return -ENFILE;
 282         }
 283
 284         tty->disc_data = hu;
 285         hu->tty = tty;
 286         tty->receive_room = 65536;
 287
 288         INIT_WORK(&hu->write_work, hci_uart_write_work);
 289
 290         spin_lock_init(&hu->rx_lock);
 291
 292         /* Flush any pending characters in the driver and line discipline. */
 293
 294         /* FIXME: why is this needed. Note don't use ldisc_ref here as the
 295            open path is before the ldisc is referencable */
 296
 297         if (tty->ldisc->ops->flush_buffer)
 298                 tty->ldisc->ops->flush_buffer(tty);
 299         tty_driver_flush_buffer(tty);
 300
 301         return 0;
 302 }
 303
 304 /* hci_uart_tty_close()
 305  *
 306  *    Called when the line discipline is changed to something
 307  *    else, the tty is closed, or the tty detects a hangup.
 308  */
 309 static void hci_uart_tty_close(struct tty_struct *tty)
 310 {
 311         struct hci_uart *hu = (void *)tty->disc_data;
 312
 313         BT_DBG("tty %p", tty);
 314
 315         /* Detach from the tty */
 316         tty->disc_data = NULL;
 317
 318         if (hu) {
 319                 struct hci_dev *hdev = hu->hdev;
 320
 321                 if (hdev)
 322                         hci_uart_close(hdev);
 323
 324                 cancel_work_sync(&hu->write_work);
 325
 326                 if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 327                         if (hdev) {
 328                                 hci_unregister_dev(hdev);
 329                                 hci_free_dev(hdev);
 330                         }
 331                         hu->proto->close(hu);
 332                 }
 333                 kfree(hu);
 334         }
 335 }
 336
 337 /* hci_uart_tty_wakeup()
 338  *
 339  *    Callback for transmit wakeup. Called when low level
 340  *    device driver can accept more send data.
 341  *
 342  * Arguments:        tty    pointer to associated tty instance data
 343  * Return Value:    None
 344  */
 345 static void hci_uart_tty_wakeup(struct tty_struct *tty)
 346 {
 347         struct hci_uart *hu = (void *)tty->disc_data;
 348
 349         BT_DBG("");
 350
 351         if (!hu)
 352                 return;
 353
 354         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 355
 356         if (tty != hu->tty)
 357                 return;
 358
 359         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 360                 hci_uart_tx_wakeup(hu);
 361 }
 362
 363 /* hci_uart_tty_receive()
 364  *
 365  *     Called by tty low level driver when receive data is
 366  *     available.
 367  *
 368  * Arguments:  tty          pointer to tty isntance data
 369  *             data         pointer to received data
 370  *             flags        pointer to flags for data
 371  *             count        count of received data in bytes
 372  *
 373  * Return Value:    None
 374  */
 375 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
 376 {
 377         struct hci_uart *hu = (void *)tty->disc_data;
 378
 379         if (!hu || tty != hu->tty)
 380                 return;
 381
 382         if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
 383                 return;
 384
 385         spin_lock(&hu->rx_lock);
 386         hu->proto->recv(hu, (void *) data, count);
 387         hu->hdev->stat.byte_rx += count;
 388         spin_unlock(&hu->rx_lock);
 389
 390         tty_unthrottle(tty);
 391 }
 392
 393 static int hci_uart_register_dev(struct hci_uart *hu)
 394 {
 395         struct hci_dev *hdev;
 396
 397         BT_DBG("");
 398
 399         /* Initialize and register HCI device */
 400         hdev = hci_alloc_dev();
 401         if (!hdev) {
 402                 BT_ERR("Can't allocate HCI device");
 403                 return -ENOMEM;
 404         }
 405
 406         hu->hdev = hdev;
 407
 408         hdev->bus = HCI_UART;
 409         hdev->driver_data = hu;
 410
 411         hdev->open  = hci_uart_open;
 412         hdev->close = hci_uart_close;
 413         hdev->flush = hci_uart_flush;
 414         hdev->send  = hci_uart_send_frame;
 415         hdev->destruct = hci_uart_destruct;
 416         hdev->parent = hu->tty->dev;
 417
 418         hdev->owner = THIS_MODULE;
 419
 420         if (!reset)
 421                 set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
 422
 423         if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
 424                 set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
 425
 426         if (hci_register_dev(hdev) < 0) {
 427                 BT_ERR("Can't register HCI device");
 428                 hci_free_dev(hdev);
 429                 return -ENODEV;
 430         }
 431
 432         return 0;
 433 }
 434
 435 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 436 {
 437         struct hci_uart_proto *p;
 438         int err;
 439
 440         p = hci_uart_get_proto(id);
 441         if (!p)
 442                 return -EPROTONOSUPPORT;
 443
 444         err = p->open(hu);
 445         if (err)
 446                 return err;
 447
 448         hu->proto = p;
 449
 450         err = hci_uart_register_dev(hu);
 451         if (err) {
 452                 p->close(hu);
 453                 return err;
 454         }
 455
 456         return 0;
 457 }
 458
 459 /* hci_uart_tty_ioctl()
 460  *
 461  *    Process IOCTL system call for the tty device.
 462  *
 463  * Arguments:
 464  *
 465  *    tty        pointer to tty instance data
 466  *    file       pointer to open file object for device
 467  *    cmd        IOCTL command code
 468  *    arg        argument for IOCTL call (cmd dependent)
 469  *
 470  * Return Value:    Command dependent
 471  */
 472 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 473                                         unsigned int cmd, unsigned long arg)
 474 {
 475         struct hci_uart *hu = (void *)tty->disc_data;
 476         int err = 0;
 477
 478         BT_DBG("");
 479
 480         /* Verify the status of the device */
 481         if (!hu)
 482                 return -EBADF;
 483
 484         switch (cmd) {
 485         case HCIUARTSETPROTO:
 486                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 487                         err = hci_uart_set_proto(hu, arg);
 488                         if (err) {
 489                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 490                                 return err;
 491                         }
 492                 } else
 493                         return -EBUSY;
 494                 break;
 495
 496         case HCIUARTGETPROTO:
 497                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 498                         return hu->proto->id;
 499                 return -EUNATCH;
 500
 501         case HCIUARTGETDEVICE:
 502                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 503                         return hu->hdev->id;
 504                 return -EUNATCH;
 505
 506         case HCIUARTSETFLAGS:
 507                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 508                         return -EBUSY;
 509                 hu->hdev_flags = arg;
 510                 break;
 511
 512         case HCIUARTGETFLAGS:
 513                 return hu->hdev_flags;
 514
 515         default:
 516                 err = n_tty_ioctl_helper(tty, file, cmd, arg);
 517                 break;
 518         };
 519
 520         return err;
 521 }
 522
 523 /*
 524  * We don't provide read/write/poll interface for user space.
 525  */
 526 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 527                                         unsigned char __user *buf, size_t nr)
 528 {
 529         return 0;
 530 }
 531
 532 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 533                                         const unsigned char *data, size_t count)
 534 {
 535         return 0;
 536 }
 537
 538 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 539                                         struct file *filp, poll_table *wait)
 540 {
 541         return 0;
 542 }
 543
 544 static int __init hci_uart_init(void)
 545 {
 546         static struct tty_ldisc_ops hci_uart_ldisc;
 547         int err;
 548
 549         BT_INFO("HCI UART driver ver %s", VERSION);
 550
 551         /* Register the tty discipline */
 552
 553         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 554         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 555         hci_uart_ldisc.name             = "n_hci";
 556         hci_uart_ldisc.open             = hci_uart_tty_open;
 557         hci_uart_ldisc.close            = hci_uart_tty_close;
 558         hci_uart_ldisc.read             = hci_uart_tty_read;
 559         hci_uart_ldisc.write            = hci_uart_tty_write;
 560         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 561         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 562         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 563         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 564         hci_uart_ldisc.owner            = THIS_MODULE;
 565
 566         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 567                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 568                 return err;
 569         }
 570
 571 #ifdef CONFIG_BT_HCIUART_H4
 572         h4_init();
 573 #endif
 574 #ifdef CONFIG_BT_HCIUART_BCSP
 575         bcsp_init();
 576 #endif
 577 #ifdef CONFIG_BT_HCIUART_LL
 578         ll_init();
 579 #endif
 580 #ifdef CONFIG_BT_HCIUART_ATH3K
 581         ath_init();
 582 #endif
 583
 584         return 0;
 585 }
 586
 587 static void __exit hci_uart_exit(void)
 588 {
 589         int err;
 590
 591 #ifdef CONFIG_BT_HCIUART_H4
 592         h4_deinit();
 593 #endif
 594 #ifdef CONFIG_BT_HCIUART_BCSP
 595         bcsp_deinit();
 596 #endif
 597 #ifdef CONFIG_BT_HCIUART_LL
 598         ll_deinit();
 599 #endif
 600 #ifdef CONFIG_BT_HCIUART_ATH3K
 601         ath_deinit();
 602 #endif
 603
 604         /* Release tty registration of line discipline */
 605         if ((err = tty_unregister_ldisc(N_HCI)))
 606                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 607 }
 608
 609 module_init(hci_uart_init);
 610 module_exit(hci_uart_exit);
 611
 612 module_param(reset, bool, 0644);
 613 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 614
 615 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
 616 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 617 MODULE_VERSION(VERSION);
 618 MODULE_LICENSE("GPL");
 619 MODULE_ALIAS_LDISC(N_HCI);