drivers/bluetooth/btuart_cs.c

   1 /*
   2  *
   3  *  Driver for Bluetooth PCMCIA cards with HCI UART interface
   4  *
   5  *  Copyright (C) 2001-2002  Marcel Holtmann <marcel@holtmann.org>
   6  *
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License version 2 as
  10  *  published by the Free Software Foundation;
  11  *
  12  *  Software distributed under the License is distributed on an "AS
  13  *  IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
  14  *  implied. See the License for the specific language governing
  15  *  rights and limitations under the License.
  16  *
  17  *  The initial developer of the original code is David A. Hinds
  18  *  <dahinds@users.sourceforge.net>.  Portions created by David A. Hinds
  19  *  are Copyright (C) 1999 David A. Hinds.  All Rights Reserved.
  20  *
  21  */
  22
  23 #include <linux/module.h>
  24
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/slab.h>
  28 #include <linux/types.h>
  29 #include <linux/delay.h>
  30 #include <linux/errno.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/ioport.h>
  33 #include <linux/spinlock.h>
  34 #include <linux/moduleparam.h>
  35
  36 #include <linux/skbuff.h>
  37 #include <linux/string.h>
  38 #include <linux/serial.h>
  39 #include <linux/serial_reg.h>
  40 #include <linux/bitops.h>
  41 #include <asm/system.h>
  42 #include <asm/io.h>
  43
  44 #include <pcmcia/cs_types.h>
  45 #include <pcmcia/cs.h>
  46 #include <pcmcia/cistpl.h>
  47 #include <pcmcia/ciscode.h>
  48 #include <pcmcia/ds.h>
  49 #include <pcmcia/cisreg.h>
  50
  51 #include <net/bluetooth/bluetooth.h>
  52 #include <net/bluetooth/hci_core.h>
  53
  54
  55
  56 /* ======================== Module parameters ======================== */
  57
  58
  59 MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
  60 MODULE_DESCRIPTION("Bluetooth driver for Bluetooth PCMCIA cards with HCI UART interface");
  61 MODULE_LICENSE("GPL");
  62
  63
  64
  65 /* ======================== Local structures ======================== */
  66
  67
  68 typedef struct btuart_info_t {
  69         struct pcmcia_device *p_dev;
  70         dev_node_t node;
  71
  72         struct hci_dev *hdev;
  73
  74         spinlock_t lock;        /* For serializing operations */
  75
  76         struct sk_buff_head txq;
  77         unsigned long tx_state;
  78
  79         unsigned long rx_state;
  80         unsigned long rx_count;
  81         struct sk_buff *rx_skb;
  82 } btuart_info_t;
  83
  84
  85 static int btuart_config(struct pcmcia_device *link);
  86 static void btuart_release(struct pcmcia_device *link);
  87
  88 static void btuart_detach(struct pcmcia_device *p_dev);
  89
  90
  91 /* Maximum baud rate */
  92 #define SPEED_MAX  115200
  93
  94 /* Default baud rate: 57600, 115200, 230400 or 460800 */
  95 #define DEFAULT_BAUD_RATE  115200
  96
  97
  98 /* Transmit states  */
  99 #define XMIT_SENDING    1
 100 #define XMIT_WAKEUP     2
 101 #define XMIT_WAITING    8
 102
 103 /* Receiver states */
 104 #define RECV_WAIT_PACKET_TYPE   0
 105 #define RECV_WAIT_EVENT_HEADER  1
 106 #define RECV_WAIT_ACL_HEADER    2
 107 #define RECV_WAIT_SCO_HEADER    3
 108 #define RECV_WAIT_DATA          4
 109
 110
 111
 112 /* ======================== Interrupt handling ======================== */
 113
 114
 115 static int btuart_write(unsigned int iobase, int fifo_size, __u8 *buf, int len)
 116 {
 117         int actual = 0;
 118
 119         /* Tx FIFO should be empty */
 120         if (!(inb(iobase + UART_LSR) & UART_LSR_THRE))
 121                 return 0;
 122
 123         /* Fill FIFO with current frame */
 124         while ((fifo_size-- > 0) && (actual < len)) {
 125                 /* Transmit next byte */
 126                 outb(buf[actual], iobase + UART_TX);
 127                 actual++;
 128         }
 129
 130         return actual;
 131 }
 132
 133
 134 static void btuart_write_wakeup(btuart_info_t *info)
 135 {
 136         if (!info) {
 137                 BT_ERR("Unknown device");
 138                 return;
 139         }
 140
 141         if (test_and_set_bit(XMIT_SENDING, &(info->tx_state))) {
 142                 set_bit(XMIT_WAKEUP, &(info->tx_state));
 143                 return;
 144         }
 145
 146         do {
 147                 register unsigned int iobase = info->p_dev->io.BasePort1;
 148                 register struct sk_buff *skb;
 149                 register int len;
 150
 151                 clear_bit(XMIT_WAKEUP, &(info->tx_state));
 152
 153                 if (!pcmcia_dev_present(info->p_dev))
 154                         return;
 155
 156                 if (!(skb = skb_dequeue(&(info->txq))))
 157                         break;
 158
 159                 /* Send frame */
 160                 len = btuart_write(iobase, 16, skb->data, skb->len);
 161                 set_bit(XMIT_WAKEUP, &(info->tx_state));
 162
 163                 if (len == skb->len) {
 164                         kfree_skb(skb);
 165                 } else {
 166                         skb_pull(skb, len);
 167                         skb_queue_head(&(info->txq), skb);
 168                 }
 169
 170                 info->hdev->stat.byte_tx += len;
 171
 172         } while (test_bit(XMIT_WAKEUP, &(info->tx_state)));
 173
 174         clear_bit(XMIT_SENDING, &(info->tx_state));
 175 }
 176
 177
 178 static void btuart_receive(btuart_info_t *info)
 179 {
 180         unsigned int iobase;
 181         int boguscount = 0;
 182
 183         if (!info) {
 184                 BT_ERR("Unknown device");
 185                 return;
 186         }
 187
 188         iobase = info->p_dev->io.BasePort1;
 189
 190         do {
 191                 info->hdev->stat.byte_rx++;
 192
 193                 /* Allocate packet */
 194                 if (info->rx_skb == NULL) {
 195                         info->rx_state = RECV_WAIT_PACKET_TYPE;
 196                         info->rx_count = 0;
 197                         if (!(info->rx_skb = bt_skb_alloc(HCI_MAX_FRAME_SIZE, GFP_ATOMIC))) {
 198                                 BT_ERR("Can't allocate mem for new packet");
 199                                 return;
 200                         }
 201                 }
 202
 203                 if (info->rx_state == RECV_WAIT_PACKET_TYPE) {
 204
 205                         info->rx_skb->dev = (void *) info->hdev;
 206                         bt_cb(info->rx_skb)->pkt_type = inb(iobase + UART_RX);
 207
 208                         switch (bt_cb(info->rx_skb)->pkt_type) {
 209
 210                         case HCI_EVENT_PKT:
 211                                 info->rx_state = RECV_WAIT_EVENT_HEADER;
 212                                 info->rx_count = HCI_EVENT_HDR_SIZE;
 213                                 break;
 214
 215                         case HCI_ACLDATA_PKT:
 216                                 info->rx_state = RECV_WAIT_ACL_HEADER;
 217                                 info->rx_count = HCI_ACL_HDR_SIZE;
 218                                 break;
 219
 220                         case HCI_SCODATA_PKT:
 221                                 info->rx_state = RECV_WAIT_SCO_HEADER;
 222                                 info->rx_count = HCI_SCO_HDR_SIZE;
 223                                 break;
 224
 225                         default:
 226                                 /* Unknown packet */
 227                                 BT_ERR("Unknown HCI packet with type 0x%02x received", bt_cb(info->rx_skb)->pkt_type);
 228                                 info->hdev->stat.err_rx++;
 229                                 clear_bit(HCI_RUNNING, &(info->hdev->flags));
 230
 231                                 kfree_skb(info->rx_skb);
 232                                 info->rx_skb = NULL;
 233                                 break;
 234
 235                         }
 236
 237                 } else {
 238
 239                         *skb_put(info->rx_skb, 1) = inb(iobase + UART_RX);
 240                         info->rx_count--;
 241
 242                         if (info->rx_count == 0) {
 243
 244                                 int dlen;
 245                                 struct hci_event_hdr *eh;
 246                                 struct hci_acl_hdr *ah;
 247                                 struct hci_sco_hdr *sh;
 248
 249
 250                                 switch (info->rx_state) {
 251
 252                                 case RECV_WAIT_EVENT_HEADER:
 253                                         eh = hci_event_hdr(info->rx_skb);
 254                                         info->rx_state = RECV_WAIT_DATA;
 255                                         info->rx_count = eh->plen;
 256                                         break;
 257
 258                                 case RECV_WAIT_ACL_HEADER:
 259                                         ah = hci_acl_hdr(info->rx_skb);
 260                                         dlen = __le16_to_cpu(ah->dlen);
 261                                         info->rx_state = RECV_WAIT_DATA;
 262                                         info->rx_count = dlen;
 263                                         break;
 264
 265                                 case RECV_WAIT_SCO_HEADER:
 266                                         sh = hci_sco_hdr(info->rx_skb);
 267                                         info->rx_state = RECV_WAIT_DATA;
 268                                         info->rx_count = sh->dlen;
 269                                         break;
 270
 271                                 case RECV_WAIT_DATA:
 272                                         hci_recv_frame(info->rx_skb);
 273                                         info->rx_skb = NULL;
 274                                         break;
 275
 276                                 }
 277
 278                         }
 279
 280                 }
 281
 282                 /* Make sure we don't stay here too long */
 283                 if (boguscount++ > 16)
 284                         break;
 285
 286         } while (inb(iobase + UART_LSR) & UART_LSR_DR);
 287 }
 288
 289
 290 static irqreturn_t btuart_interrupt(int irq, void *dev_inst)
 291 {
 292         btuart_info_t *info = dev_inst;
 293         unsigned int iobase;
 294         int boguscount = 0;
 295         int iir, lsr;
 296         irqreturn_t r = IRQ_NONE;
 297
 298         BUG_ON(!info->hdev);
 299
 300         iobase = info->p_dev->io.BasePort1;
 301
 302         spin_lock(&(info->lock));
 303
 304         iir = inb(iobase + UART_IIR) & UART_IIR_ID;
 305         while (iir) {
 306                 r = IRQ_HANDLED;
 307
 308                 /* Clear interrupt */
 309                 lsr = inb(iobase + UART_LSR);
 310
 311                 switch (iir) {
 312                 case UART_IIR_RLSI:
 313                         BT_ERR("RLSI");
 314                         break;
 315                 case UART_IIR_RDI:
 316                         /* Receive interrupt */
 317                         btuart_receive(info);
 318                         break;
 319                 case UART_IIR_THRI:
 320                         if (lsr & UART_LSR_THRE) {
 321                                 /* Transmitter ready for data */
 322                                 btuart_write_wakeup(info);
 323                         }
 324                         break;
 325                 default:
 326                         BT_ERR("Unhandled IIR=%#x", iir);
 327                         break;
 328                 }
 329
 330                 /* Make sure we don't stay here too long */
 331                 if (boguscount++ > 100)
 332                         break;
 333
 334                 iir = inb(iobase + UART_IIR) & UART_IIR_ID;
 335
 336         }
 337
 338         spin_unlock(&(info->lock));
 339
 340         return r;
 341 }
 342
 343
 344 static void btuart_change_speed(btuart_info_t *info, unsigned int speed)
 345 {
 346         unsigned long flags;
 347         unsigned int iobase;
 348         int fcr;                /* FIFO control reg */
 349         int lcr;                /* Line control reg */
 350         int divisor;
 351
 352         if (!info) {
 353                 BT_ERR("Unknown device");
 354                 return;
 355         }
 356
 357         iobase = info->p_dev->io.BasePort1;
 358
 359         spin_lock_irqsave(&(info->lock), flags);
 360
 361         /* Turn off interrupts */
 362         outb(0, iobase + UART_IER);
 363
 364         divisor = SPEED_MAX / speed;
 365
 366         fcr = UART_FCR_ENABLE_FIFO | UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT;
 367
 368         /*
 369          * Use trigger level 1 to avoid 3 ms. timeout delay at 9600 bps, and
 370          * almost 1,7 ms at 19200 bps. At speeds above that we can just forget
 371          * about this timeout since it will always be fast enough.
 372          */
 373
 374         if (speed < 38400)
 375                 fcr |= UART_FCR_TRIGGER_1;
 376         else
 377                 fcr |= UART_FCR_TRIGGER_14;
 378
 379         /* Bluetooth cards use 8N1 */
 380         lcr = UART_LCR_WLEN8;
 381
 382         outb(UART_LCR_DLAB | lcr, iobase + UART_LCR);   /* Set DLAB */
 383         outb(divisor & 0xff, iobase + UART_DLL);        /* Set speed */
 384         outb(divisor >> 8, iobase + UART_DLM);
 385         outb(lcr, iobase + UART_LCR);   /* Set 8N1  */
 386         outb(fcr, iobase + UART_FCR);   /* Enable FIFO's */
 387
 388         /* Turn on interrupts */
 389         outb(UART_IER_RLSI | UART_IER_RDI | UART_IER_THRI, iobase + UART_IER);
 390
 391         spin_unlock_irqrestore(&(info->lock), flags);
 392 }
 393
 394
 395
 396 /* ======================== HCI interface ======================== */
 397
 398
 399 static int btuart_hci_flush(struct hci_dev *hdev)
 400 {
 401         btuart_info_t *info = (btuart_info_t *)(hdev->driver_data);
 402
 403         /* Drop TX queue */
 404         skb_queue_purge(&(info->txq));
 405
 406         return 0;
 407 }
 408
 409
 410 static int btuart_hci_open(struct hci_dev *hdev)
 411 {
 412         set_bit(HCI_RUNNING, &(hdev->flags));
 413
 414         return 0;
 415 }
 416
 417
 418 static int btuart_hci_close(struct hci_dev *hdev)
 419 {
 420         if (!test_and_clear_bit(HCI_RUNNING, &(hdev->flags)))
 421                 return 0;
 422
 423         btuart_hci_flush(hdev);
 424
 425         return 0;
 426 }
 427
 428
 429 static int btuart_hci_send_frame(struct sk_buff *skb)
 430 {
 431         btuart_info_t *info;
 432         struct hci_dev *hdev = (struct hci_dev *)(skb->dev);
 433
 434         if (!hdev) {
 435                 BT_ERR("Frame for unknown HCI device (hdev=NULL)");
 436                 return -ENODEV;
 437         }
 438
 439         info = (btuart_info_t *)(hdev->driver_data);
 440
 441         switch (bt_cb(skb)->pkt_type) {
 442         case HCI_COMMAND_PKT:
 443                 hdev->stat.cmd_tx++;
 444                 break;
 445         case HCI_ACLDATA_PKT:
 446                 hdev->stat.acl_tx++;
 447                 break;
 448         case HCI_SCODATA_PKT:
 449                 hdev->stat.sco_tx++;
 450                 break;
 451         };
 452
 453         /* Prepend skb with frame type */
 454         memcpy(skb_push(skb, 1), &bt_cb(skb)->pkt_type, 1);
 455         skb_queue_tail(&(info->txq), skb);
 456
 457         btuart_write_wakeup(info);
 458
 459         return 0;
 460 }
 461
 462
 463 static void btuart_hci_destruct(struct hci_dev *hdev)
 464 {
 465 }
 466
 467
 468 static int btuart_hci_ioctl(struct hci_dev *hdev, unsigned int cmd, unsigned long arg)
 469 {
 470         return -ENOIOCTLCMD;
 471 }
 472
 473
 474
 475 /* ======================== Card services HCI interaction ======================== */
 476
 477
 478 static int btuart_open(btuart_info_t *info)
 479 {
 480         unsigned long flags;
 481         unsigned int iobase = info->p_dev->io.BasePort1;
 482         struct hci_dev *hdev;
 483
 484         spin_lock_init(&(info->lock));
 485
 486         skb_queue_head_init(&(info->txq));
 487
 488         info->rx_state = RECV_WAIT_PACKET_TYPE;
 489         info->rx_count = 0;
 490         info->rx_skb = NULL;
 491
 492         /* Initialize HCI device */
 493         hdev = hci_alloc_dev();
 494         if (!hdev) {
 495                 BT_ERR("Can't allocate HCI device");
 496                 return -ENOMEM;
 497         }
 498
 499         info->hdev = hdev;
 500
 501         hdev->type = HCI_PCCARD;
 502         hdev->driver_data = info;
 503         SET_HCIDEV_DEV(hdev, &info->p_dev->dev);
 504
 505         hdev->open     = btuart_hci_open;
 506         hdev->close    = btuart_hci_close;
 507         hdev->flush    = btuart_hci_flush;
 508         hdev->send     = btuart_hci_send_frame;
 509         hdev->destruct = btuart_hci_destruct;
 510         hdev->ioctl    = btuart_hci_ioctl;
 511
 512         hdev->owner = THIS_MODULE;
 513
 514         spin_lock_irqsave(&(info->lock), flags);
 515
 516         /* Reset UART */
 517         outb(0, iobase + UART_MCR);
 518
 519         /* Turn off interrupts */
 520         outb(0, iobase + UART_IER);
 521
 522         /* Initialize UART */
 523         outb(UART_LCR_WLEN8, iobase + UART_LCR);        /* Reset DLAB */
 524         outb((UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2), iobase + UART_MCR);
 525
 526         /* Turn on interrupts */
 527         // outb(UART_IER_RLSI | UART_IER_RDI | UART_IER_THRI, iobase + UART_IER);
 528
 529         spin_unlock_irqrestore(&(info->lock), flags);
 530
 531         btuart_change_speed(info, DEFAULT_BAUD_RATE);
 532
 533         /* Timeout before it is safe to send the first HCI packet */
 534         msleep(1000);
 535
 536         /* Register HCI device */
 537         if (hci_register_dev(hdev) < 0) {
 538                 BT_ERR("Can't register HCI device");
 539                 info->hdev = NULL;
 540                 hci_free_dev(hdev);
 541                 return -ENODEV;
 542         }
 543
 544         return 0;
 545 }
 546
 547
 548 static int btuart_close(btuart_info_t *info)
 549 {
 550         unsigned long flags;
 551         unsigned int iobase = info->p_dev->io.BasePort1;
 552         struct hci_dev *hdev = info->hdev;
 553
 554         if (!hdev)
 555                 return -ENODEV;
 556
 557         btuart_hci_close(hdev);
 558
 559         spin_lock_irqsave(&(info->lock), flags);
 560
 561         /* Reset UART */
 562         outb(0, iobase + UART_MCR);
 563
 564         /* Turn off interrupts */
 565         outb(0, iobase + UART_IER);
 566
 567         spin_unlock_irqrestore(&(info->lock), flags);
 568
 569         if (hci_unregister_dev(hdev) < 0)
 570                 BT_ERR("Can't unregister HCI device %s", hdev->name);
 571
 572         hci_free_dev(hdev);
 573
 574         return 0;
 575 }
 576
 577 static int btuart_probe(struct pcmcia_device *link)
 578 {
 579         btuart_info_t *info;
 580
 581         /* Create new info device */
 582         info = kzalloc(sizeof(*info), GFP_KERNEL);
 583         if (!info)
 584                 return -ENOMEM;
 585
 586         info->p_dev = link;
 587         link->priv = info;
 588
 589         link->io.Attributes1 = IO_DATA_PATH_WIDTH_8;
 590         link->io.NumPorts1 = 8;
 591         link->irq.Attributes = IRQ_TYPE_DYNAMIC_SHARING;
 592
 593         link->irq.Handler = btuart_interrupt;
 594
 595         link->conf.Attributes = CONF_ENABLE_IRQ;
 596         link->conf.IntType = INT_MEMORY_AND_IO;
 597
 598         return btuart_config(link);
 599 }
 600
 601
 602 static void btuart_detach(struct pcmcia_device *link)
 603 {
 604         btuart_info_t *info = link->priv;
 605
 606         btuart_release(link);
 607         kfree(info);
 608 }
 609
 610 static int btuart_check_config(struct pcmcia_device *p_dev,
 611                                cistpl_cftable_entry_t *cf,
 612                                cistpl_cftable_entry_t *dflt,
 613                                unsigned int vcc,
 614                                void *priv_data)
 615 {
 616         int *try = priv_data;
 617
 618         if (cf->vpp1.present & (1 << CISTPL_POWER_VNOM))
 619                 p_dev->conf.Vpp = cf->vpp1.param[CISTPL_POWER_VNOM] / 10000;
 620         if ((cf->io.nwin > 0) && (cf->io.win[0].len == 8) &&
 621             (cf->io.win[0].base != 0)) {
 622                 p_dev->io.BasePort1 = cf->io.win[0].base;
 623                 p_dev->io.IOAddrLines = (*try == 0) ? 16 :
 624                         cf->io.flags & CISTPL_IO_LINES_MASK;
 625                 if (!pcmcia_request_io(p_dev, &p_dev->io))
 626                         return 0;
 627         }
 628         return -ENODEV;
 629 }
 630
 631 static int btuart_check_config_notpicky(struct pcmcia_device *p_dev,
 632                                         cistpl_cftable_entry_t *cf,
 633                                         cistpl_cftable_entry_t *dflt,
 634                                         unsigned int vcc,
 635                                         void *priv_data)
 636 {
 637         static unsigned int base[5] = { 0x3f8, 0x2f8, 0x3e8, 0x2e8, 0x0 };
 638         int j;
 639
 640         if ((cf->io.nwin > 0) && ((cf->io.flags & CISTPL_IO_LINES_MASK) <= 3)) {
 641                 for (j = 0; j < 5; j++) {
 642                         p_dev->io.BasePort1 = base[j];
 643                         p_dev->io.IOAddrLines = base[j] ? 16 : 3;
 644                         if (!pcmcia_request_io(p_dev, &p_dev->io))
 645                                 return 0;
 646                 }
 647         }
 648         return -ENODEV;
 649 }
 650
 651 static int btuart_config(struct pcmcia_device *link)
 652 {
 653         btuart_info_t *info = link->priv;
 654         int i;
 655         int try;
 656
 657         /* First pass: look for a config entry that looks normal.
 658            Two tries: without IO aliases, then with aliases */
 659         for (try = 0; try < 2; try++)
 660                 if (!pcmcia_loop_config(link, btuart_check_config, &try))
 661                         goto found_port;
 662
 663         /* Second pass: try to find an entry that isn't picky about
 664            its base address, then try to grab any standard serial port
 665            address, and finally try to get any free port. */
 666         if (!pcmcia_loop_config(link, btuart_check_config_notpicky, NULL))
 667                 goto found_port;
 668
 669         BT_ERR("No usable port range found");
 670         goto failed;
 671
 672 found_port:
 673         i = pcmcia_request_irq(link, &link->irq);
 674         if (i != 0)
 675                 link->irq.AssignedIRQ = 0;
 676
 677         i = pcmcia_request_configuration(link, &link->conf);
 678         if (i != 0)
 679                 goto failed;
 680
 681         if (btuart_open(info) != 0)
 682                 goto failed;
 683
 684         strcpy(info->node.dev_name, info->hdev->name);
 685         link->dev_node = &info->node;
 686
 687         return 0;
 688
 689 failed:
 690         btuart_release(link);
 691         return -ENODEV;
 692 }
 693
 694
 695 static void btuart_release(struct pcmcia_device *link)
 696 {
 697         btuart_info_t *info = link->priv;
 698
 699         btuart_close(info);
 700
 701         pcmcia_disable_device(link);
 702 }
 703
 704 static struct pcmcia_device_id btuart_ids[] = {
 705         /* don't use this driver. Use serial_cs + hci_uart instead */
 706         PCMCIA_DEVICE_NULL
 707 };
 708 MODULE_DEVICE_TABLE(pcmcia, btuart_ids);
 709
 710 static struct pcmcia_driver btuart_driver = {
 711         .owner          = THIS_MODULE,
 712         .drv            = {
 713                 .name   = "btuart_cs",
 714         },
 715         .probe          = btuart_probe,
 716         .remove         = btuart_detach,
 717         .id_table       = btuart_ids,
 718 };
 719
 720 static int __init init_btuart_cs(void)
 721 {
 722         return pcmcia_register_driver(&btuart_driver);
 723 }
 724
 725
 726 static void __exit exit_btuart_cs(void)
 727 {
 728         pcmcia_unregister_driver(&btuart_driver);
 729 }
 730
 731 module_init(init_btuart_cs);
 732 module_exit(exit_btuart_cs);