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/config.h>
  27 #include <linux/module.h>
  28
  29 #include <linux/kernel.h>
  30 #include <linux/init.h>
  31 #include <linux/sched.h>
  32 #include <linux/types.h>
  33 #include <linux/fcntl.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/ptrace.h>
  36 #include <linux/poll.h>
  37
  38 #include <linux/slab.h>
  39 #include <linux/tty.h>
  40 #include <linux/errno.h>
  41 #include <linux/string.h>
  42 #include <linux/signal.h>
  43 #include <linux/ioctl.h>
  44 #include <linux/skbuff.h>
  45
  46 #include <net/bluetooth/bluetooth.h>
  47 #include <net/bluetooth/hci_core.h>
  48
  49 #include "hci_uart.h"
  50
  51 #ifndef CONFIG_BT_HCIUART_DEBUG
  52 #undef  BT_DBG
  53 #define BT_DBG( A... )
  54 #endif
  55
  56 #define VERSION "2.2"
  57
  58 static int reset = 0;
  59
  60 static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
  61
  62 int hci_uart_register_proto(struct hci_uart_proto *p)
  63 {
  64         if (p->id >= HCI_UART_MAX_PROTO)
  65                 return -EINVAL;
  66
  67         if (hup[p->id])
  68                 return -EEXIST;
  69
  70         hup[p->id] = p;
  71
  72         return 0;
  73 }
  74
  75 int hci_uart_unregister_proto(struct hci_uart_proto *p)
  76 {
  77         if (p->id >= HCI_UART_MAX_PROTO)
  78                 return -EINVAL;
  79
  80         if (!hup[p->id])
  81                 return -EINVAL;
  82
  83         hup[p->id] = NULL;
  84
  85         return 0;
  86 }
  87
  88 static struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
  89 {
  90         if (id >= HCI_UART_MAX_PROTO)
  91                 return NULL;
  92
  93         return hup[id];
  94 }
  95
  96 static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
  97 {
  98         struct hci_dev *hdev = hu->hdev;
  99
 100         /* Update HCI stat counters */
 101         switch (pkt_type) {
 102         case HCI_COMMAND_PKT:
 103                 hdev->stat.cmd_tx++;
 104                 break;
 105
 106         case HCI_ACLDATA_PKT:
 107                 hdev->stat.acl_tx++;
 108                 break;
 109
 110         case HCI_SCODATA_PKT:
 111                 hdev->stat.cmd_tx++;
 112                 break;
 113         }
 114 }
 115
 116 static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
 117 {
 118         struct sk_buff *skb = hu->tx_skb;
 119
 120         if (!skb)
 121                 skb = hu->proto->dequeue(hu);
 122         else
 123                 hu->tx_skb = NULL;
 124
 125         return skb;
 126 }
 127
 128 int hci_uart_tx_wakeup(struct hci_uart *hu)
 129 {
 130         struct tty_struct *tty = hu->tty;
 131         struct hci_dev *hdev = hu->hdev;
 132         struct sk_buff *skb;
 133
 134         if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
 135                 set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 136                 return 0;
 137         }
 138
 139         BT_DBG("");
 140
 141 restart:
 142         clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
 143
 144         while ((skb = hci_uart_dequeue(hu))) {
 145                 int len;
 146
 147                 set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 148                 len = tty->driver->write(tty, skb->data, skb->len);
 149                 hdev->stat.byte_tx += len;
 150
 151                 skb_pull(skb, len);
 152                 if (skb->len) {
 153                         hu->tx_skb = skb;
 154                         break;
 155                 }
 156
 157                 hci_uart_tx_complete(hu, bt_cb(skb)->pkt_type);
 158                 kfree_skb(skb);
 159         }
 160
 161         if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
 162                 goto restart;
 163
 164         clear_bit(HCI_UART_SENDING, &hu->tx_state);
 165         return 0;
 166 }
 167
 168 /* ------- Interface to HCI layer ------ */
 169 /* Initialize device */
 170 static int hci_uart_open(struct hci_dev *hdev)
 171 {
 172         BT_DBG("%s %p", hdev->name, hdev);
 173
 174         /* Nothing to do for UART driver */
 175
 176         set_bit(HCI_RUNNING, &hdev->flags);
 177
 178         return 0;
 179 }
 180
 181 /* Reset device */
 182 static int hci_uart_flush(struct hci_dev *hdev)
 183 {
 184         struct hci_uart *hu  = (struct hci_uart *) hdev->driver_data;
 185         struct tty_struct *tty = hu->tty;
 186
 187         BT_DBG("hdev %p tty %p", hdev, tty);
 188
 189         if (hu->tx_skb) {
 190                 kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
 191         }
 192
 193         /* Flush any pending characters in the driver and discipline. */
 194         tty_ldisc_flush(tty);
 195         if (tty->driver->flush_buffer)
 196                 tty->driver->flush_buffer(tty);
 197
 198         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 199                 hu->proto->flush(hu);
 200
 201         return 0;
 202 }
 203
 204 /* Close device */
 205 static int hci_uart_close(struct hci_dev *hdev)
 206 {
 207         BT_DBG("hdev %p", hdev);
 208
 209         if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
 210                 return 0;
 211
 212         hci_uart_flush(hdev);
 213         return 0;
 214 }
 215
 216 /* Send frames from HCI layer */
 217 static int hci_uart_send_frame(struct sk_buff *skb)
 218 {
 219         struct hci_dev* hdev = (struct hci_dev *) skb->dev;
 220         struct tty_struct *tty;
 221         struct hci_uart *hu;
 222
 223         if (!hdev) {
 224                 BT_ERR("Frame for uknown device (hdev=NULL)");
 225                 return -ENODEV;
 226         }
 227
 228         if (!test_bit(HCI_RUNNING, &hdev->flags))
 229                 return -EBUSY;
 230
 231         hu = (struct hci_uart *) hdev->driver_data;
 232         tty = hu->tty;
 233
 234         BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
 235
 236         hu->proto->enqueue(hu, skb);
 237
 238         hci_uart_tx_wakeup(hu);
 239
 240         return 0;
 241 }
 242
 243 static void hci_uart_destruct(struct hci_dev *hdev)
 244 {
 245         struct hci_uart *hu;
 246
 247         if (!hdev)
 248                 return;
 249
 250         BT_DBG("%s", hdev->name);
 251
 252         hu = (struct hci_uart *) hdev->driver_data;
 253         kfree(hu);
 254 }
 255
 256 /* ------ LDISC part ------ */
 257 /* hci_uart_tty_open
 258  *
 259  *     Called when line discipline changed to HCI_UART.
 260  *
 261  * Arguments:
 262  *     tty    pointer to tty info structure
 263  * Return Value:
 264  *     0 if success, otherwise error code
 265  */
 266 static int hci_uart_tty_open(struct tty_struct *tty)
 267 {
 268         struct hci_uart *hu = (void *) tty->disc_data;
 269
 270         BT_DBG("tty %p", tty);
 271
 272         if (hu)
 273                 return -EEXIST;
 274
 275         if (!(hu = kmalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
 276                 BT_ERR("Can't allocate controll structure");
 277                 return -ENFILE;
 278         }
 279
 280         memset(hu, 0, sizeof(struct hci_uart));
 281
 282         tty->disc_data = hu;
 283         hu->tty = tty;
 284
 285         spin_lock_init(&hu->rx_lock);
 286
 287         /* Flush any pending characters in the driver and line discipline. */
 288
 289         /* FIXME: why is this needed. Note don't use ldisc_ref here as the
 290            open path is before the ldisc is referencable */
 291
 292         if (tty->ldisc.flush_buffer)
 293                 tty->ldisc.flush_buffer(tty);
 294
 295         if (tty->driver->flush_buffer)
 296                 tty->driver->flush_buffer(tty);
 297
 298         return 0;
 299 }
 300
 301 /* hci_uart_tty_close()
 302  *
 303  *    Called when the line discipline is changed to something
 304  *    else, the tty is closed, or the tty detects a hangup.
 305  */
 306 static void hci_uart_tty_close(struct tty_struct *tty)
 307 {
 308         struct hci_uart *hu = (void *)tty->disc_data;
 309
 310         BT_DBG("tty %p", tty);
 311
 312         /* Detach from the tty */
 313         tty->disc_data = NULL;
 314
 315         if (hu) {
 316                 struct hci_dev *hdev = hu->hdev;
 317                 hci_uart_close(hdev);
 318
 319                 if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 320                         hu->proto->close(hu);
 321                         hci_unregister_dev(hdev);
 322                         hci_free_dev(hdev);
 323                 }
 324         }
 325 }
 326
 327 /* hci_uart_tty_wakeup()
 328  *
 329  *    Callback for transmit wakeup. Called when low level
 330  *    device driver can accept more send data.
 331  *
 332  * Arguments:        tty    pointer to associated tty instance data
 333  * Return Value:    None
 334  */
 335 static void hci_uart_tty_wakeup(struct tty_struct *tty)
 336 {
 337         struct hci_uart *hu = (void *)tty->disc_data;
 338
 339         BT_DBG("");
 340
 341         if (!hu)
 342                 return;
 343
 344         clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
 345
 346         if (tty != hu->tty)
 347                 return;
 348
 349         if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 350                 hci_uart_tx_wakeup(hu);
 351 }
 352
 353 /* hci_uart_tty_room()
 354  *
 355  *    Callback function from tty driver. Return the amount of
 356  *    space left in the receiver's buffer to decide if remote
 357  *    transmitter is to be throttled.
 358  *
 359  * Arguments:        tty    pointer to associated tty instance data
 360  * Return Value:    number of bytes left in receive buffer
 361  */
 362 static int hci_uart_tty_room (struct tty_struct *tty)
 363 {
 364         return 65536;
 365 }
 366
 367 /* hci_uart_tty_receive()
 368  *
 369  *     Called by tty low level driver when receive data is
 370  *     available.
 371  *
 372  * Arguments:  tty          pointer to tty isntance data
 373  *             data         pointer to received data
 374  *             flags        pointer to flags for data
 375  *             count        count of received data in bytes
 376  *
 377  * Return Value:    None
 378  */
 379 static void hci_uart_tty_receive(struct tty_struct *tty, const __u8 *data, char *flags, int count)
 380 {
 381         struct hci_uart *hu = (void *)tty->disc_data;
 382
 383         if (!hu || tty != hu->tty)
 384                 return;
 385
 386         if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
 387                 return;
 388
 389         spin_lock(&hu->rx_lock);
 390         hu->proto->recv(hu, (void *) data, count);
 391         hu->hdev->stat.byte_rx += count;
 392         spin_unlock(&hu->rx_lock);
 393
 394         if (test_and_clear_bit(TTY_THROTTLED,&tty->flags) && tty->driver->unthrottle)
 395                 tty->driver->unthrottle(tty);
 396 }
 397
 398 static int hci_uart_register_dev(struct hci_uart *hu)
 399 {
 400         struct hci_dev *hdev;
 401
 402         BT_DBG("");
 403
 404         /* Initialize and register HCI device */
 405         hdev = hci_alloc_dev();
 406         if (!hdev) {
 407                 BT_ERR("Can't allocate HCI device");
 408                 return -ENOMEM;
 409         }
 410
 411         hu->hdev = hdev;
 412
 413         hdev->type = HCI_UART;
 414         hdev->driver_data = hu;
 415
 416         hdev->open  = hci_uart_open;
 417         hdev->close = hci_uart_close;
 418         hdev->flush = hci_uart_flush;
 419         hdev->send  = hci_uart_send_frame;
 420         hdev->destruct = hci_uart_destruct;
 421
 422         hdev->owner = THIS_MODULE;
 423
 424         if (reset)
 425                 set_bit(HCI_QUIRK_RESET_ON_INIT, &hdev->quirks);
 426
 427         if (hci_register_dev(hdev) < 0) {
 428                 BT_ERR("Can't register HCI device");
 429                 hci_free_dev(hdev);
 430                 return -ENODEV;
 431         }
 432
 433         return 0;
 434 }
 435
 436 static int hci_uart_set_proto(struct hci_uart *hu, int id)
 437 {
 438         struct hci_uart_proto *p;
 439         int err;
 440
 441         p = hci_uart_get_proto(id);
 442         if (!p)
 443                 return -EPROTONOSUPPORT;
 444
 445         err = p->open(hu);
 446         if (err)
 447                 return err;
 448
 449         hu->proto = p;
 450
 451         err = hci_uart_register_dev(hu);
 452         if (err) {
 453                 p->close(hu);
 454                 return err;
 455         }
 456
 457         return 0;
 458 }
 459
 460 /* hci_uart_tty_ioctl()
 461  *
 462  *    Process IOCTL system call for the tty device.
 463  *
 464  * Arguments:
 465  *
 466  *    tty        pointer to tty instance data
 467  *    file       pointer to open file object for device
 468  *    cmd        IOCTL command code
 469  *    arg        argument for IOCTL call (cmd dependent)
 470  *
 471  * Return Value:    Command dependent
 472  */
 473 static int hci_uart_tty_ioctl(struct tty_struct *tty, struct file * file,
 474                                         unsigned int cmd, unsigned long arg)
 475 {
 476         struct hci_uart *hu = (void *)tty->disc_data;
 477         int err = 0;
 478
 479         BT_DBG("");
 480
 481         /* Verify the status of the device */
 482         if (!hu)
 483                 return -EBADF;
 484
 485         switch (cmd) {
 486         case HCIUARTSETPROTO:
 487                 if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
 488                         err = hci_uart_set_proto(hu, arg);
 489                         if (err) {
 490                                 clear_bit(HCI_UART_PROTO_SET, &hu->flags);
 491                                 return err;
 492                         }
 493                         tty->low_latency = 1;
 494                 } else
 495                         return -EBUSY;
 496
 497         case HCIUARTGETPROTO:
 498                 if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
 499                         return hu->proto->id;
 500                 return -EUNATCH;
 501
 502         default:
 503                 err = n_tty_ioctl(tty, file, cmd, arg);
 504                 break;
 505         };
 506
 507         return err;
 508 }
 509
 510 /*
 511  * We don't provide read/write/poll interface for user space.
 512  */
 513 static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
 514                                         unsigned char __user *buf, size_t nr)
 515 {
 516         return 0;
 517 }
 518
 519 static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
 520                                         const unsigned char *data, size_t count)
 521 {
 522         return 0;
 523 }
 524
 525 static unsigned int hci_uart_tty_poll(struct tty_struct *tty,
 526                                         struct file *filp, poll_table *wait)
 527 {
 528         return 0;
 529 }
 530
 531 static int __init hci_uart_init(void)
 532 {
 533         static struct tty_ldisc hci_uart_ldisc;
 534         int err;
 535
 536         BT_INFO("HCI UART driver ver %s", VERSION);
 537
 538         /* Register the tty discipline */
 539
 540         memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
 541         hci_uart_ldisc.magic            = TTY_LDISC_MAGIC;
 542         hci_uart_ldisc.name             = "n_hci";
 543         hci_uart_ldisc.open             = hci_uart_tty_open;
 544         hci_uart_ldisc.close            = hci_uart_tty_close;
 545         hci_uart_ldisc.read             = hci_uart_tty_read;
 546         hci_uart_ldisc.write            = hci_uart_tty_write;
 547         hci_uart_ldisc.ioctl            = hci_uart_tty_ioctl;
 548         hci_uart_ldisc.poll             = hci_uart_tty_poll;
 549         hci_uart_ldisc.receive_room     = hci_uart_tty_room;
 550         hci_uart_ldisc.receive_buf      = hci_uart_tty_receive;
 551         hci_uart_ldisc.write_wakeup     = hci_uart_tty_wakeup;
 552         hci_uart_ldisc.owner            = THIS_MODULE;
 553
 554         if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
 555                 BT_ERR("HCI line discipline registration failed. (%d)", err);
 556                 return err;
 557         }
 558
 559 #ifdef CONFIG_BT_HCIUART_H4
 560         h4_init();
 561 #endif
 562 #ifdef CONFIG_BT_HCIUART_BCSP
 563         bcsp_init();
 564 #endif
 565
 566         return 0;
 567 }
 568
 569 static void __exit hci_uart_exit(void)
 570 {
 571         int err;
 572
 573 #ifdef CONFIG_BT_HCIUART_H4
 574         h4_deinit();
 575 #endif
 576 #ifdef CONFIG_BT_HCIUART_BCSP
 577         bcsp_deinit();
 578 #endif
 579
 580         /* Release tty registration of line discipline */
 581         if ((err = tty_unregister_ldisc(N_HCI)))
 582                 BT_ERR("Can't unregister HCI line discipline (%d)", err);
 583 }
 584
 585 module_init(hci_uart_init);
 586 module_exit(hci_uart_exit);
 587
 588 module_param(reset, bool, 0644);
 589 MODULE_PARM_DESC(reset, "Send HCI reset command on initialization");
 590
 591 MODULE_AUTHOR("Maxim Krasnyansky <maxk@qualcomm.com>, Marcel Holtmann <marcel@holtmann.org>");
 592 MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
 593 MODULE_VERSION(VERSION);
 594 MODULE_LICENSE("GPL");
 595 MODULE_ALIAS_LDISC(N_HCI);