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/sched.h>
  31 #include <linux/types.h>
  32 #include <linux/fcntl.h>
  33 #include <linux/interrupt.h>
  34 #include <linux/ptrace.h>
  35 #include <linux/poll.h>
  36
  37 #include <linux/slab.h>
  38 #include <linux/tty.h>
  39 #include <linux/errno.h>
  40 #include <linux/string.h>
  41 #include <linux/signal.h>
  42 #include <linux/ioctl.h>
  43 #include <linux/skbuff.h>
  44
  45 #include <net/bluetooth/bluetooth.h>
  46 #include <net/bluetooth/hci_core.h>
  47
  48 #include "hci_uart.h"
  49
  50 #ifndef CONFIG_BT_HCIUART_DEBUG
  51 #undef  BT_DBG
  52 #define BT_DBG( A... )
  53 #endif
  54
  55 #define VERSION "2.2"
  56
  57 static int reset = 0;
  58
  59 static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
  60
  61 int hci_uart_register_proto(struct hci_uart_proto *p)
  62 {
  63         if (p->id >= HCI_UART_MAX_PROTO)
  64                 return -EINVAL;
  65
  66         if (hup[p->id])
  67                 return -EEXIST;
  68
  69         hup[p->id] = p;
  70
  71         return 0;
  72 }
  73
  74 int hci_uart_unregister_proto(struct hci_uart_proto *p)
  75 {
  76         if (p->id >= HCI_UART_MAX_PROTO)
  77                 return -EINVAL;
  78
  79         if (!hup[p->id])
  80                 return -EINVAL;
  81
  82         hup[p->id] = NULL;
  83
  84         return 0;
  85 }
  86
  87 static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
  88 {
  89         if (id >= HCI_UART_MAX_PROTO)
  90                 return NULL;
  91
  92         return hup[id];
  93 }
  94
  95 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
  96 {
  97         struct hci_dev *hdev = hu->hdev;
  98
  99         /* Update HCI stat counters */
 100         switch (pkt_type) {
 101         case HCI_COMMAND_PKT:
 102                 hdev->stat.cmd_tx++;
 103                 break;
 104
 105         case HCI_ACLDATA_PKT:
 106                 hdev->stat.acl_tx++;
 107                 break;
 108
 109         case HCI_SCODATA_PKT:
 110                 hdev->stat.cmd_tx++;
 111                 break;
 112         }
 113 }
 114
 115 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
 116 {
 117         struct sk_buff *skb = hu->tx_skb;
 118
 119         if (!skb)
 120                 skb = hu->proto->dequeue(hu);
 121         else
 122                 hu->tx_skb = NULL;
 123
 124         return skb;
 125 }
 126
 127 int hci_uart_tx_wakeup(struct hci_uart *hu)
 128 {
 129         struct tty_struct *tty = hu->tty;
 130         struct hci_dev *hdev = hu->hdev;
 131         struct sk_buff *skb;
 132
 133         if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
 134                 set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 135                 return 0;
 136         }
 137
 138         BT_DBG("");
 139
 140 restart:
 141         clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 142
 143         while ((skb = hci_uart_dequeue(hu))) {
 144                 int len;
 145
 146                 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 147                 len = tty->driver->write(tty, skb->data, skb->len);
 148                 hdev->stat.byte_tx += len;
 149
 150                 skb_pull(skb, len);
 151                 if (skb->len) {
 152                         hu->tx_skb = skb;
 153                         break;
 154                 }
 155
 156                 hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
 157                 kfree_skb(skb);
 158         }
 159
 160         if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
 161                 goto restart;
 162
 163         clear_bit(HCI_UART_SENDING, &hu->tx_state);
 164         return 0;
 165 }
 166
 167 /* ------- Interface to HCI layer ------ */
 168 /* Initialize device */
 169 static int hci_uart_open(struct hci_dev *hdev)
 170 {
 171         BT_DBG("%s %p", hdev->name, hdev);
 172
 173         /* Nothing to do for UART driver */
 174
 175         set_bit(HCI_RUNNING, &hdev->flags);
 176
 177         return 0;
 178 }
 179
 180 /* Reset device */
 181 static int hci_uart_flush(struct hci_dev *hdev)
 182 {
 183         struct hci_uart *hu  = (struct hci_uart *) hdev->driver_data;
 184         struct tty_struct *tty = hu->tty;
 185
 186         BT_DBG("hdev %p tty %p", hdev, tty);
 187
 188         if (hu->tx_skb) {
 189                 kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 190         }
 191
 192         /* Flush any pending characters in the driver and discipline. */
 193         tty_ldisc_flush(tty);
 194         if (tty->driver && tty->driver->flush_buffer)
 195                 tty->driver->flush_buffer(tty);
 196
 197         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 198                 hu->proto->flush(hu);
 199
 200         return 0;
 201 }
 202
 203 /* Close device */
 204 static int hci_uart_close(struct hci_dev *hdev)
 205 {
 206         BT_DBG("hdev %p", hdev);
 207
 208         if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
 209                 return 0;
 210
 211         hci_uart_flush(hdev);
 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                 hci_uart_close(hdev);
 312
 313                 if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 314                         hu->proto->close(hu);
 315                         hci_unregister_dev(hdev);
 316                         hci_free_dev(hdev);
 317                 }
 318         }
 319 }
 320
 321 /* hci_uart_tty_wakeup()
 322  *
 323  *    Callback for transmit wakeup. Called when low level
 324  *    device driver can accept more send data.
 325  *
 326  * Arguments:        tty    pointer to associated tty instance data
 327  * Return Value:    None
 328  */
 329 static void hci_uart_tty_wakeup(struct tty_struct *tty)
 330 {
 331         struct hci_uart *hu = (void *)tty->disc_data;
 332
 333         BT_DBG("");
 334
 335         if (!hu)
 336                 return;
 337
 338         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 339
 340         if (tty != hu->tty)
 341                 return;
 342
 343         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 344                 hci_uart_tx_wakeup(hu);
 345 }
 346
 347 /* hci_uart_tty_receive()
 348  *
 349  *     Called by tty low level driver when receive data is
 350  *     available.
 351  *
 352  * Arguments:  tty          pointer to tty isntance data
 353  *             data         pointer to received data
 354  *             flags        pointer to flags for data
 355  *             count        count of received data in bytes
 356  *
 357  * Return Value:    None
 358  */
 359 static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data, char *flags, int count)
 360 {
 361         struct hci_uart *hu = (void *)tty->disc_data;
 362
 363         if (!hu || tty != hu->tty)
 364                 return;
 365
 366         if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
 367                 return;
 368
 369         spin_lock(&hu->rx_lock);
 370         hu->proto->recv(hu, (void *) data, count);
 371         hu->hdev->stat.byte_rx += count;
 372         spin_unlock(&hu->rx_lock);
 373
 374         if (test_and_clear_bit(TTY_THROTTLED, &tty->flags) &&
 375                                         tty->driver->unthrottle)
 376                 tty->driver->unthrottle(tty);
 377 }
 378
 379 static int hci_uart_register_dev(struct hci_uart *hu)
 380 {
 381         struct hci_dev *hdev;
 382
 383         BT_DBG("");
 384
 385         /* Initialize and register HCI device */
 386         hdev = hci_alloc_dev();
 387         if (!hdev) {
 388                 BT_ERR("Can't allocate HCI device");
 389                 return -ENOMEM;
 390         }
 391
 392         hu->hdev = hdev;
 393
 394         hdev->type = HCI_UART;
 395         hdev->driver_data = hu;
 396
 397         hdev->open  = hci_uart_open;
 398         hdev->close = hci_uart_close;
 399         hdev->flush = hci_uart_flush;
 400         hdev->send  = hci_uart_send_frame;
 401         hdev->destruct = hci_uart_destruct;
 402
 403         hdev->owner = THIS_MODULE;
 404
 405         if (reset)
 406                 set_bit(HCI_QUIRK_RESET_ON_INIT, &hdev->quirks);
 407
 408         if (hci_register_dev(hdev) < 0) {
 409                 BT_ERR("Can't register HCI device");
 410                 hci_free_dev(hdev);
 411                 return -ENODEV;
 412         }
 413
 414         return 0;
 415 }
 416
 417 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 418 {
 419         struct hci_uart_proto *p;
 420         int err;
 421
 422         p = hci_uart_get_proto(id);
 423         if (!p)
 424                 return -EPROTONOSUPPORT;
 425
 426         err = p->open(hu);
 427         if (err)
 428                 return err;
 429
 430         hu->proto = p;
 431
 432         err = hci_uart_register_dev(hu);
 433         if (err) {
 434                 p->close(hu);
 435                 return err;
 436         }
 437
 438         return 0;
 439 }
 440
 441 /* hci_uart_tty_ioctl()
 442  *
 443  *    Process IOCTL system call for the tty device.
 444  *
 445  * Arguments:
 446  *
 447  *    tty        pointer to tty instance data
 448  *    file       pointer to open file object for device
 449  *    cmd        IOCTL command code
 450  *    arg        argument for IOCTL call (cmd dependent)
 451  *
 452  * Return Value:    Command dependent
 453  */
 454 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 455                                         unsigned int cmd, unsigned long arg)
 456 {
 457         struct hci_uart *hu = (void *)tty->disc_data;
 458         int err = 0;
 459
 460         BT_DBG("");
 461
 462         /* Verify the status of the device */
 463         if (!hu)
 464                 return -EBADF;
 465
 466         switch (cmd) {
 467         case HCIUARTSETPROTO:
 468                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 469                         err = hci_uart_set_proto(hu, arg);
 470                         if (err) {
 471                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 472                                 return err;
 473                         }
 474                         tty->low_latency = 1;
 475                 } else
 476                         return -EBUSY;
 477
 478         case HCIUARTGETPROTO:
 479                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 480                         return hu->proto->id;
 481                 return -EUNATCH;
 482
 483         default:
 484                 err = n_tty_ioctl(tty, file, cmd, arg);
 485                 break;
 486         };
 487
 488         return err;
 489 }
 490
 491 /*
 492  * We don't provide read/write/poll interface for user space.
 493  */
 494 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 495                                         unsigned char __user *buf, size_t nr)
 496 {
 497         return 0;
 498 }
 499
 500 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 501                                         const unsigned char *data, size_t count)
 502 {
 503         return 0;
 504 }
 505
 506 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 507                                         struct file *filp, poll_table *wait)
 508 {
 509         return 0;
 510 }
 511
 512 static int __init hci_uart_init(void)
 513 {
 514         static struct tty_ldisc hci_uart_ldisc;
 515         int err;
 516
 517         BT_INFO("HCI UART driver ver %s", VERSION);
 518
 519         /* Register the tty discipline */
 520
 521         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 522         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 523         hci_uart_ldisc.name             = "n_hci";
 524         hci_uart_ldisc.open             = hci_uart_tty_open;
 525         hci_uart_ldisc.close            = hci_uart_tty_close;
 526         hci_uart_ldisc.read             = hci_uart_tty_read;
 527         hci_uart_ldisc.write            = hci_uart_tty_write;
 528         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 529         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 530         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 531         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 532         hci_uart_ldisc.owner            = THIS_MODULE;
 533
 534         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 535                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 536                 return err;
 537         }
 538
 539 #ifdef CONFIG_BT_HCIUART_H4
 540         h4_init();
 541 #endif
 542 #ifdef CONFIG_BT_HCIUART_BCSP
 543         bcsp_init();
 544 #endif
 545
 546         return 0;
 547 }
 548
 549 static void __exit hci_uart_exit(void)
 550 {
 551         int err;
 552
 553 #ifdef CONFIG_BT_HCIUART_H4
 554         h4_deinit();
 555 #endif
 556 #ifdef CONFIG_BT_HCIUART_BCSP
 557         bcsp_deinit();
 558 #endif
 559
 560         /* Release tty registration of line discipline */
 561         if ((err = tty_unregister_ldisc(N_HCI)))
 562                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 563 }
 564
 565 module_init(hci_uart_init);
 566 module_exit(hci_uart_exit);
 567
 568 module_param(reset, bool, 0644);
 569 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 570
 571 MODULE_AUTHOR("Maxim Krasnyansky <maxk@qualcomm.com>, Marcel Holtmann <marcel@holtmann.org>");
 572 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 573 MODULE_VERSION(VERSION);
 574 MODULE_LICENSE("GPL");
 575 MODULE_ALIAS_LDISC(N_HCI);