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         hdev->flush = NULL;
 212         return 0;
 213 }
 214
 215 /* Send frames from HCI layer */
 216 static int hci_uart_send_frame(struct sk_buff *skb)
 217 {
 218         struct hci_dev* hdev = (struct hci_dev *) skb->dev;
 219         struct tty_struct *tty;
 220         struct hci_uart *hu;
 221
 222         if (!hdev) {
 223                 BT_ERR("Frame for uknown device (hdev=NULL)");
 224                 return -ENODEV;
 225         }
 226
 227         if (!test_bit(HCI_RUNNING, &hdev->flags))
 228                 return -EBUSY;
 229
 230         hu = (struct hci_uart *) hdev->driver_data;
 231         tty = hu->tty;
 232
 233         BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
 234
 235         hu->proto->enqueue(hu, skb);
 236
 237         hci_uart_tx_wakeup(hu);
 238
 239         return 0;
 240 }
 241
 242 static void hci_uart_destruct(struct hci_dev *hdev)
 243 {
 244         if (!hdev)
 245                 return;
 246
 247         BT_DBG("%s", hdev->name);
 248         kfree(hdev->driver_data);
 249 }
 250
 251 /* ------ LDISC part ------ */
 252 /* hci_uart_tty_open
 253  *
 254  *     Called when line discipline changed to HCI_UART.
 255  *
 256  * Arguments:
 257  *     tty    pointer to tty info structure
 258  * Return Value:
 259  *     0 if success, otherwise error code
 260  */
 261 static int hci_uart_tty_open(struct tty_struct *tty)
 262 {
 263         struct hci_uart *hu = (void *) tty->disc_data;
 264
 265         BT_DBG("tty %p", tty);
 266
 267         if (hu)
 268                 return -EEXIST;
 269
 270         if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
 271                 BT_ERR("Can't allocate control structure");
 272                 return -ENFILE;
 273         }
 274
 275         tty->disc_data = hu;
 276         hu->tty = tty;
 277         tty->receive_room = 65536;
 278
 279         spin_lock_init(&hu->rx_lock);
 280
 281         /* Flush any pending characters in the driver and line discipline. */
 282
 283         /* FIXME: why is this needed. Note don't use ldisc_ref here as the
 284            open path is before the ldisc is referencable */
 285
 286         if (tty->ldisc.flush_buffer)
 287                 tty->ldisc.flush_buffer(tty);
 288
 289         if (tty->driver && tty->driver->flush_buffer)
 290                 tty->driver->flush_buffer(tty);
 291
 292         return 0;
 293 }
 294
 295 /* hci_uart_tty_close()
 296  *
 297  *    Called when the line discipline is changed to something
 298  *    else, the tty is closed, or the tty detects a hangup.
 299  */
 300 static void hci_uart_tty_close(struct tty_struct *tty)
 301 {
 302         struct hci_uart *hu = (void *)tty->disc_data;
 303
 304         BT_DBG("tty %p", tty);
 305
 306         /* Detach from the tty */
 307         tty->disc_data = NULL;
 308
 309         if (hu) {
 310                 struct hci_dev *hdev = hu->hdev;
 311
 312                 if (hdev)
 313                         hci_uart_close(hdev);
 314
 315                 if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 316                         hu->proto->close(hu);
 317                         hci_unregister_dev(hdev);
 318                         hci_free_dev(hdev);
 319                 }
 320         }
 321 }
 322
 323 /* hci_uart_tty_wakeup()
 324  *
 325  *    Callback for transmit wakeup. Called when low level
 326  *    device driver can accept more send data.
 327  *
 328  * Arguments:        tty    pointer to associated tty instance data
 329  * Return Value:    None
 330  */
 331 static void hci_uart_tty_wakeup(struct tty_struct *tty)
 332 {
 333         struct hci_uart *hu = (void *)tty->disc_data;
 334
 335         BT_DBG("");
 336
 337         if (!hu)
 338                 return;
 339
 340         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 341
 342         if (tty != hu->tty)
 343                 return;
 344
 345         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 346                 hci_uart_tx_wakeup(hu);
 347 }
 348
 349 /* hci_uart_tty_receive()
 350  *
 351  *     Called by tty low level driver when receive data is
 352  *     available.
 353  *
 354  * Arguments:  tty          pointer to tty isntance data
 355  *             data         pointer to received data
 356  *             flags        pointer to flags for data
 357  *             count        count of received data in bytes
 358  *
 359  * Return Value:    None
 360  */
 361 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
 362 {
 363         struct hci_uart *hu = (void *)tty->disc_data;
 364
 365         if (!hu || tty != hu->tty)
 366                 return;
 367
 368         if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
 369                 return;
 370
 371         spin_lock(&hu->rx_lock);
 372         hu->proto->recv(hu, (void *) data, count);
 373         hu->hdev->stat.byte_rx += count;
 374         spin_unlock(&hu->rx_lock);
 375
 376         if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
 377                                         tty->driver->unthrottle)
 378                 tty->driver->unthrottle(tty);
 379 }
 380
 381 static int hci_uart_register_dev(struct hci_uart *hu)
 382 {
 383         struct hci_dev *hdev;
 384
 385         BT_DBG("");
 386
 387         /* Initialize and register HCI device */
 388         hdev = hci_alloc_dev();
 389         if (!hdev) {
 390                 BT_ERR("Can't allocate HCI device");
 391                 return -ENOMEM;
 392         }
 393
 394         hu->hdev = hdev;
 395
 396         hdev->type = HCI_UART;
 397         hdev->driver_data = hu;
 398
 399         hdev->open  = hci_uart_open;
 400         hdev->close = hci_uart_close;
 401         hdev->flush = hci_uart_flush;
 402         hdev->send  = hci_uart_send_frame;
 403         hdev->destruct = hci_uart_destruct;
 404
 405         hdev->owner = THIS_MODULE;
 406
 407         if (reset)
 408                 set_bit(HCI_QUIRK_RESET_ON_INIT, &hdev->quirks);
 409
 410         if (hci_register_dev(hdev) < 0) {
 411                 BT_ERR("Can't register HCI device");
 412                 hci_free_dev(hdev);
 413                 return -ENODEV;
 414         }
 415
 416         return 0;
 417 }
 418
 419 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 420 {
 421         struct hci_uart_proto *p;
 422         int err;
 423
 424         p = hci_uart_get_proto(id);
 425         if (!p)
 426                 return -EPROTONOSUPPORT;
 427
 428         err = p->open(hu);
 429         if (err)
 430                 return err;
 431
 432         hu->proto = p;
 433
 434         err = hci_uart_register_dev(hu);
 435         if (err) {
 436                 p->close(hu);
 437                 return err;
 438         }
 439
 440         return 0;
 441 }
 442
 443 /* hci_uart_tty_ioctl()
 444  *
 445  *    Process IOCTL system call for the tty device.
 446  *
 447  * Arguments:
 448  *
 449  *    tty        pointer to tty instance data
 450  *    file       pointer to open file object for device
 451  *    cmd        IOCTL command code
 452  *    arg        argument for IOCTL call (cmd dependent)
 453  *
 454  * Return Value:    Command dependent
 455  */
 456 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 457                                         unsigned int cmd, unsigned long arg)
 458 {
 459         struct hci_uart *hu = (void *)tty->disc_data;
 460         int err = 0;
 461
 462         BT_DBG("");
 463
 464         /* Verify the status of the device */
 465         if (!hu)
 466                 return -EBADF;
 467
 468         switch (cmd) {
 469         case HCIUARTSETPROTO:
 470                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 471                         err = hci_uart_set_proto(hu, arg);
 472                         if (err) {
 473                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 474                                 return err;
 475                         }
 476                         tty->low_latency = 1;
 477                 } else
 478                         return -EBUSY;
 479                 break;
 480
 481         case HCIUARTGETPROTO:
 482                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 483                         return hu->proto->id;
 484                 return -EUNATCH;
 485
 486         case HCIUARTGETDEVICE:
 487                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 488                         return hu->hdev->id;
 489                 return -EUNATCH;
 490
 491         default:
 492                 err = n_tty_ioctl(tty, file, cmd, arg);
 493                 break;
 494         };
 495
 496         return err;
 497 }
 498
 499 /*
 500  * We don't provide read/write/poll interface for user space.
 501  */
 502 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 503                                         unsigned char __user *buf, size_t nr)
 504 {
 505         return 0;
 506 }
 507
 508 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 509                                         const unsigned char *data, size_t count)
 510 {
 511         return 0;
 512 }
 513
 514 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 515                                         struct file *filp, poll_table *wait)
 516 {
 517         return 0;
 518 }
 519
 520 static int __init hci_uart_init(void)
 521 {
 522         static struct tty_ldisc hci_uart_ldisc;
 523         int err;
 524
 525         BT_INFO("HCI UART driver ver %s", VERSION);
 526
 527         /* Register the tty discipline */
 528
 529         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 530         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 531         hci_uart_ldisc.name             = "n_hci";
 532         hci_uart_ldisc.open             = hci_uart_tty_open;
 533         hci_uart_ldisc.close            = hci_uart_tty_close;
 534         hci_uart_ldisc.read             = hci_uart_tty_read;
 535         hci_uart_ldisc.write            = hci_uart_tty_write;
 536         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 537         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 538         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 539         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 540         hci_uart_ldisc.owner            = THIS_MODULE;
 541
 542         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 543                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 544                 return err;
 545         }
 546
 547 #ifdef CONFIG_BT_HCIUART_H4
 548         h4_init();
 549 #endif
 550 #ifdef CONFIG_BT_HCIUART_BCSP
 551         bcsp_init();
 552 #endif
 553 #ifdef CONFIG_BT_HCIUART_LL
 554         ll_init();
 555 #endif
 556
 557         return 0;
 558 }
 559
 560 static void __exit hci_uart_exit(void)
 561 {
 562         int err;
 563
 564 #ifdef CONFIG_BT_HCIUART_H4
 565         h4_deinit();
 566 #endif
 567 #ifdef CONFIG_BT_HCIUART_BCSP
 568         bcsp_deinit();
 569 #endif
 570 #ifdef CONFIG_BT_HCIUART_LL
 571         ll_deinit();
 572 #endif
 573
 574         /* Release tty registration of line discipline */
 575         if ((err = tty_unregister_ldisc(N_HCI)))
 576                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 577 }
 578
 579 module_init(hci_uart_init);
 580 module_exit(hci_uart_exit);
 581
 582 module_param(reset, bool, 0644);
 583 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 584
 585 MODULE_AUTHOR("Maxim Krasnyansky <maxk@qualcomm.com>, Marcel Holtmann <marcel@holtmann.org>");
 586 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 587 MODULE_VERSION(VERSION);
 588 MODULE_LICENSE("GPL");
 589 MODULE_ALIAS_LDISC(N_HCI);