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->driver->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         if (tty->driver && tty->driver->flush_buffer)
 194                 tty->driver->flush_buffer(tty);
 195
 196         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 197                 hu->proto->flush(hu);
 198
 199         return 0;
 200 }
 201
 202 /* Close device */
 203 static int hci_uart_close(struct hci_dev *hdev)
 204 {
 205         BT_DBG("hdev %p", hdev);
 206
 207         if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
 208                 return 0;
 209
 210         hci_uart_flush(hdev);
 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.flush_buffer)
 286                 tty->ldisc.flush_buffer(tty);
 287
 288         if (tty->driver && tty->driver->flush_buffer)
 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         if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
 376                                         tty->driver->unthrottle)
 377                 tty->driver->unthrottle(tty);
 378 }
 379
 380 static int hci_uart_register_dev(struct hci_uart *hu)
 381 {
 382         struct hci_dev *hdev;
 383
 384         BT_DBG("");
 385
 386         /* Initialize and register HCI device */
 387         hdev = hci_alloc_dev();
 388         if (!hdev) {
 389                 BT_ERR("Can't allocate HCI device");
 390                 return -ENOMEM;
 391         }
 392
 393         hu->hdev = hdev;
 394
 395         hdev->type = HCI_UART;
 396         hdev->driver_data = hu;
 397
 398         hdev->open  = hci_uart_open;
 399         hdev->close = hci_uart_close;
 400         hdev->flush = hci_uart_flush;
 401         hdev->send  = hci_uart_send_frame;
 402         hdev->destruct = hci_uart_destruct;
 403
 404         hdev->owner = THIS_MODULE;
 405
 406         if (reset)
 407                 set_bit(HCI_QUIRK_RESET_ON_INIT, &hdev->quirks);
 408
 409         if (hci_register_dev(hdev) < 0) {
 410                 BT_ERR("Can't register HCI device");
 411                 hci_free_dev(hdev);
 412                 return -ENODEV;
 413         }
 414
 415         return 0;
 416 }
 417
 418 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 419 {
 420         struct hci_uart_proto *p;
 421         int err;
 422
 423         p = hci_uart_get_proto(id);
 424         if (!p)
 425                 return -EPROTONOSUPPORT;
 426
 427         err = p->open(hu);
 428         if (err)
 429                 return err;
 430
 431         hu->proto = p;
 432
 433         err = hci_uart_register_dev(hu);
 434         if (err) {
 435                 p->close(hu);
 436                 return err;
 437         }
 438
 439         return 0;
 440 }
 441
 442 /* hci_uart_tty_ioctl()
 443  *
 444  *    Process IOCTL system call for the tty device.
 445  *
 446  * Arguments:
 447  *
 448  *    tty        pointer to tty instance data
 449  *    file       pointer to open file object for device
 450  *    cmd        IOCTL command code
 451  *    arg        argument for IOCTL call (cmd dependent)
 452  *
 453  * Return Value:    Command dependent
 454  */
 455 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 456                                         unsigned int cmd, unsigned long arg)
 457 {
 458         struct hci_uart *hu = (void *)tty->disc_data;
 459         int err = 0;
 460
 461         BT_DBG("");
 462
 463         /* Verify the status of the device */
 464         if (!hu)
 465                 return -EBADF;
 466
 467         switch (cmd) {
 468         case HCIUARTSETPROTO:
 469                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 470                         err = hci_uart_set_proto(hu, arg);
 471                         if (err) {
 472                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 473                                 return err;
 474                         }
 475                         tty->low_latency = 1;
 476                 } else
 477                         return -EBUSY;
 478                 break;
 479
 480         case HCIUARTGETPROTO:
 481                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 482                         return hu->proto->id;
 483                 return -EUNATCH;
 484
 485         case HCIUARTGETDEVICE:
 486                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 487                         return hu->hdev->id;
 488                 return -EUNATCH;
 489
 490         default:
 491                 err = n_tty_ioctl(tty, file, cmd, arg);
 492                 break;
 493         };
 494
 495         return err;
 496 }
 497
 498 /*
 499  * We don't provide read/write/poll interface for user space.
 500  */
 501 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 502                                         unsigned char __user *buf, size_t nr)
 503 {
 504         return 0;
 505 }
 506
 507 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 508                                         const unsigned char *data, size_t count)
 509 {
 510         return 0;
 511 }
 512
 513 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 514                                         struct file *filp, poll_table *wait)
 515 {
 516         return 0;
 517 }
 518
 519 static int __init hci_uart_init(void)
 520 {
 521         static struct tty_ldisc hci_uart_ldisc;
 522         int err;
 523
 524         BT_INFO("HCI UART driver ver %s", VERSION);
 525
 526         /* Register the tty discipline */
 527
 528         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 529         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 530         hci_uart_ldisc.name             = "n_hci";
 531         hci_uart_ldisc.open             = hci_uart_tty_open;
 532         hci_uart_ldisc.close            = hci_uart_tty_close;
 533         hci_uart_ldisc.read             = hci_uart_tty_read;
 534         hci_uart_ldisc.write            = hci_uart_tty_write;
 535         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 536         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 537         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 538         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 539         hci_uart_ldisc.owner            = THIS_MODULE;
 540
 541         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 542                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 543                 return err;
 544         }
 545
 546 #ifdef CONFIG_BT_HCIUART_H4
 547         h4_init();
 548 #endif
 549 #ifdef CONFIG_BT_HCIUART_BCSP
 550         bcsp_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
 567         /* Release tty registration of line discipline */
 568         if ((err = tty_unregister_ldisc(N_HCI)))
 569                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 570 }
 571
 572 module_init(hci_uart_init);
 573 module_exit(hci_uart_exit);
 574
 575 module_param(reset, bool, 0644);
 576 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 577
 578 MODULE_AUTHOR("Maxim Krasnyansky <maxk@qualcomm.com>, Marcel Holtmann <marcel@holtmann.org>");
 579 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 580 MODULE_VERSION(VERSION);
 581 MODULE_LICENSE("GPL");
 582 MODULE_ALIAS_LDISC(N_HCI);