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 uknown 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         if (hu)
 262                 return -EEXIST;
 263
 264         if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
 265                 BT_ERR("Can't allocate control structure");
 266                 return -ENFILE;
 267         }
 268
 269         tty->disc_data = hu;
 270         hu->tty = tty;
 271         tty->receive_room = 65536;
 272
 273         spin_lock_init(&hu->rx_lock);
 274
 275         /* Flush any pending characters in the driver and line discipline. */
 276
 277         /* FIXME: why is this needed. Note don't use ldisc_ref here as the
 278            open path is before the ldisc is referencable */
 279
 280         if (tty->ldisc.ops->flush_buffer)
 281                 tty->ldisc.ops->flush_buffer(tty);
 282         tty_driver_flush_buffer(tty);
 283
 284         return 0;
 285 }
 286
 287 /* hci_uart_tty_close()
 288  *
 289  *    Called when the line discipline is changed to something
 290  *    else, the tty is closed, or the tty detects a hangup.
 291  */
 292 static void hci_uart_tty_close(struct tty_struct *tty)
 293 {
 294         struct hci_uart *hu = (void *)tty->disc_data;
 295
 296         BT_DBG("tty %p", tty);
 297
 298         /* Detach from the tty */
 299         tty->disc_data = NULL;
 300
 301         if (hu) {
 302                 struct hci_dev *hdev = hu->hdev;
 303
 304                 if (hdev)
 305                         hci_uart_close(hdev);
 306
 307                 if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 308                         hu->proto->close(hu);
 309                         hci_unregister_dev(hdev);
 310                         hci_free_dev(hdev);
 311                 }
 312         }
 313 }
 314
 315 /* hci_uart_tty_wakeup()
 316  *
 317  *    Callback for transmit wakeup. Called when low level
 318  *    device driver can accept more send data.
 319  *
 320  * Arguments:        tty    pointer to associated tty instance data
 321  * Return Value:    None
 322  */
 323 static void hci_uart_tty_wakeup(struct tty_struct *tty)
 324 {
 325         struct hci_uart *hu = (void *)tty->disc_data;
 326
 327         BT_DBG("");
 328
 329         if (!hu)
 330                 return;
 331
 332         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 333
 334         if (tty != hu->tty)
 335                 return;
 336
 337         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 338                 hci_uart_tx_wakeup(hu);
 339 }
 340
 341 /* hci_uart_tty_receive()
 342  *
 343  *     Called by tty low level driver when receive data is
 344  *     available.
 345  *
 346  * Arguments:  tty          pointer to tty isntance data
 347  *             data         pointer to received data
 348  *             flags        pointer to flags for data
 349  *             count        count of received data in bytes
 350  *
 351  * Return Value:    None
 352  */
 353 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
 354 {
 355         struct hci_uart *hu = (void *)tty->disc_data;
 356
 357         if (!hu || tty != hu->tty)
 358                 return;
 359
 360         if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
 361                 return;
 362
 363         spin_lock(&hu->rx_lock);
 364         hu->proto->recv(hu, (void *) data, count);
 365         hu->hdev->stat.byte_rx += count;
 366         spin_unlock(&hu->rx_lock);
 367
 368         tty_unthrottle(tty);
 369 }
 370
 371 static int hci_uart_register_dev(struct hci_uart *hu)
 372 {
 373         struct hci_dev *hdev;
 374
 375         BT_DBG("");
 376
 377         /* Initialize and register HCI device */
 378         hdev = hci_alloc_dev();
 379         if (!hdev) {
 380                 BT_ERR("Can't allocate HCI device");
 381                 return -ENOMEM;
 382         }
 383
 384         hu->hdev = hdev;
 385
 386         hdev->type = HCI_UART;
 387         hdev->driver_data = hu;
 388
 389         hdev->open  = hci_uart_open;
 390         hdev->close = hci_uart_close;
 391         hdev->flush = hci_uart_flush;
 392         hdev->send  = hci_uart_send_frame;
 393         hdev->destruct = hci_uart_destruct;
 394
 395         hdev->owner = THIS_MODULE;
 396
 397         if (!reset)
 398                 set_bit(HCI_QUIRK_NO_RESET, &hdev->quirks);
 399
 400         if (hci_register_dev(hdev) < 0) {
 401                 BT_ERR("Can't register HCI device");
 402                 hci_free_dev(hdev);
 403                 return -ENODEV;
 404         }
 405
 406         return 0;
 407 }
 408
 409 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 410 {
 411         struct hci_uart_proto *p;
 412         int err;
 413
 414         p = hci_uart_get_proto(id);
 415         if (!p)
 416                 return -EPROTONOSUPPORT;
 417
 418         err = p->open(hu);
 419         if (err)
 420                 return err;
 421
 422         hu->proto = p;
 423
 424         err = hci_uart_register_dev(hu);
 425         if (err) {
 426                 p->close(hu);
 427                 return err;
 428         }
 429
 430         return 0;
 431 }
 432
 433 /* hci_uart_tty_ioctl()
 434  *
 435  *    Process IOCTL system call for the tty device.
 436  *
 437  * Arguments:
 438  *
 439  *    tty        pointer to tty instance data
 440  *    file       pointer to open file object for device
 441  *    cmd        IOCTL command code
 442  *    arg        argument for IOCTL call (cmd dependent)
 443  *
 444  * Return Value:    Command dependent
 445  */
 446 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 447                                         unsigned int cmd, unsigned long arg)
 448 {
 449         struct hci_uart *hu = (void *)tty->disc_data;
 450         int err = 0;
 451
 452         BT_DBG("");
 453
 454         /* Verify the status of the device */
 455         if (!hu)
 456                 return -EBADF;
 457
 458         switch (cmd) {
 459         case HCIUARTSETPROTO:
 460                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 461                         err = hci_uart_set_proto(hu, arg);
 462                         if (err) {
 463                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 464                                 return err;
 465                         }
 466                         tty->low_latency = 1;
 467                 } else
 468                         return -EBUSY;
 469                 break;
 470
 471         case HCIUARTGETPROTO:
 472                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 473                         return hu->proto->id;
 474                 return -EUNATCH;
 475
 476         case HCIUARTGETDEVICE:
 477                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 478                         return hu->hdev->id;
 479                 return -EUNATCH;
 480
 481         default:
 482                 err = n_tty_ioctl_helper(tty, file, cmd, arg);
 483                 break;
 484         };
 485
 486         return err;
 487 }
 488
 489 /*
 490  * We don't provide read/write/poll interface for user space.
 491  */
 492 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 493                                         unsigned char __user *buf, size_t nr)
 494 {
 495         return 0;
 496 }
 497
 498 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 499                                         const unsigned char *data, size_t count)
 500 {
 501         return 0;
 502 }
 503
 504 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 505                                         struct file *filp, poll_table *wait)
 506 {
 507         return 0;
 508 }
 509
 510 static int __init hci_uart_init(void)
 511 {
 512         static struct tty_ldisc_ops hci_uart_ldisc;
 513         int err;
 514
 515         BT_INFO("HCI UART driver ver %s", VERSION);
 516
 517         /* Register the tty discipline */
 518
 519         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 520         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 521         hci_uart_ldisc.name             = "n_hci";
 522         hci_uart_ldisc.open             = hci_uart_tty_open;
 523         hci_uart_ldisc.close            = hci_uart_tty_close;
 524         hci_uart_ldisc.read             = hci_uart_tty_read;
 525         hci_uart_ldisc.write            = hci_uart_tty_write;
 526         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 527         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 528         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 529         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 530         hci_uart_ldisc.owner            = THIS_MODULE;
 531
 532         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 533                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 534                 return err;
 535         }
 536
 537 #ifdef CONFIG_BT_HCIUART_H4
 538         h4_init();
 539 #endif
 540 #ifdef CONFIG_BT_HCIUART_BCSP
 541         bcsp_init();
 542 #endif
 543 #ifdef CONFIG_BT_HCIUART_LL
 544         ll_init();
 545 #endif
 546
 547         return 0;
 548 }
 549
 550 static void __exit hci_uart_exit(void)
 551 {
 552         int err;
 553
 554 #ifdef CONFIG_BT_HCIUART_H4
 555         h4_deinit();
 556 #endif
 557 #ifdef CONFIG_BT_HCIUART_BCSP
 558         bcsp_deinit();
 559 #endif
 560 #ifdef CONFIG_BT_HCIUART_LL
 561         ll_deinit();
 562 #endif
 563
 564         /* Release tty registration of line discipline */
 565         if ((err = tty_unregister_ldisc(N_HCI)))
 566                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 567 }
 568
 569 module_init(hci_uart_init);
 570 module_exit(hci_uart_exit);
 571
 572 module_param(reset, bool, 0644);
 573 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 574
 575 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
 576 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 577 MODULE_VERSION(VERSION);
 578 MODULE_LICENSE("GPL");
 579 MODULE_ALIAS_LDISC(N_HCI);