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