drivers/usb/serial/generic.c

   1 /*
   2  * USB Serial Converter Generic functions
   3  *
   4  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License version
   8  *      2 as published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/slab.h>
  15 #include <linux/tty.h>
  16 #include <linux/tty_flip.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/usb.h>
  20 #include <linux/usb/serial.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/kfifo.h>
  23 #include <linux/serial.h>
  24
  25 static int debug;
  26
  27 #ifdef CONFIG_USB_SERIAL_GENERIC
  28
  29 static int generic_probe(struct usb_interface *interface,
  30                          const struct usb_device_id *id);
  31
  32 static __u16 vendor  = 0x05f9;
  33 static __u16 product = 0xffff;
  34
  35 module_param(vendor, ushort, 0);
  36 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  37
  38 module_param(product, ushort, 0);
  39 MODULE_PARM_DESC(product, "User specified USB idProduct");
  40
  41 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  42
  43 /* we want to look at all devices, as the vendor/product id can change
  44  * depending on the command line argument */
  45 static const struct usb_device_id generic_serial_ids[] = {
  46         {.driver_info = 42},
  47         {}
  48 };
  49
  50 static struct usb_driver generic_driver = {
  51         .name =         "usbserial_generic",
  52         .probe =        generic_probe,
  53         .disconnect =   usb_serial_disconnect,
  54         .id_table =     generic_serial_ids,
  55         .no_dynamic_id =        1,
  56 };
  57
  58 /* All of the device info needed for the Generic Serial Converter */
  59 struct usb_serial_driver usb_serial_generic_device = {
  60         .driver = {
  61                 .owner =        THIS_MODULE,
  62                 .name =         "generic",
  63         },
  64         .id_table =             generic_device_ids,
  65         .usb_driver =           &generic_driver,
  66         .num_ports =            1,
  67         .disconnect =           usb_serial_generic_disconnect,
  68         .release =              usb_serial_generic_release,
  69         .throttle =             usb_serial_generic_throttle,
  70         .unthrottle =           usb_serial_generic_unthrottle,
  71         .resume =               usb_serial_generic_resume,
  72 };
  73
  74 static int generic_probe(struct usb_interface *interface,
  75                                const struct usb_device_id *id)
  76 {
  77         const struct usb_device_id *id_pattern;
  78
  79         id_pattern = usb_match_id(interface, generic_device_ids);
  80         if (id_pattern != NULL)
  81                 return usb_serial_probe(interface, id);
  82         return -ENODEV;
  83 }
  84 #endif
  85
  86 int usb_serial_generic_register(int _debug)
  87 {
  88         int retval = 0;
  89
  90         debug = _debug;
  91 #ifdef CONFIG_USB_SERIAL_GENERIC
  92         generic_device_ids[0].idVendor = vendor;
  93         generic_device_ids[0].idProduct = product;
  94         generic_device_ids[0].match_flags =
  95                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  96
  97         /* register our generic driver with ourselves */
  98         retval = usb_serial_register(&usb_serial_generic_device);
  99         if (retval)
 100                 goto exit;
 101         retval = usb_register(&generic_driver);
 102         if (retval)
 103                 usb_serial_deregister(&usb_serial_generic_device);
 104 exit:
 105 #endif
 106         return retval;
 107 }
 108
 109 void usb_serial_generic_deregister(void)
 110 {
 111 #ifdef CONFIG_USB_SERIAL_GENERIC
 112         /* remove our generic driver */
 113         usb_deregister(&generic_driver);
 114         usb_serial_deregister(&usb_serial_generic_device);
 115 #endif
 116 }
 117
 118 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 119 {
 120         struct usb_serial *serial = port->serial;
 121         int result = 0;
 122         unsigned long flags;
 123
 124         dbg("%s - port %d", __func__, port->number);
 125
 126         /* clear the throttle flags */
 127         spin_lock_irqsave(&port->lock, flags);
 128         port->throttled = 0;
 129         port->throttle_req = 0;
 130         spin_unlock_irqrestore(&port->lock, flags);
 131
 132         /* if we have a bulk endpoint, start reading from it */
 133         if (serial->num_bulk_in) {
 134                 /* Start reading from the device */
 135                 usb_fill_bulk_urb(port->read_urb, serial->dev,
 136                                    usb_rcvbulkpipe(serial->dev,
 137                                                 port->bulk_in_endpointAddress),
 138                                    port->read_urb->transfer_buffer,
 139                                    port->read_urb->transfer_buffer_length,
 140                                    ((serial->type->read_bulk_callback) ?
 141                                      serial->type->read_bulk_callback :
 142                                      usb_serial_generic_read_bulk_callback),
 143                                    port);
 144                 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
 145                 if (result)
 146                         dev_err(&port->dev,
 147                             "%s - failed resubmitting read urb, error %d\n",
 148                                                         __func__, result);
 149         }
 150
 151         return result;
 152 }
 153 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 154
 155 static void generic_cleanup(struct usb_serial_port *port)
 156 {
 157         struct usb_serial *serial = port->serial;
 158
 159         dbg("%s - port %d", __func__, port->number);
 160
 161         if (serial->dev) {
 162                 /* shutdown any bulk reads that might be going on */
 163                 if (serial->num_bulk_out)
 164                         usb_kill_urb(port->write_urb);
 165                 if (serial->num_bulk_in)
 166                         usb_kill_urb(port->read_urb);
 167         }
 168 }
 169
 170 void usb_serial_generic_close(struct usb_serial_port *port)
 171 {
 172         dbg("%s - port %d", __func__, port->number);
 173         generic_cleanup(port);
 174 }
 175
 176 static int usb_serial_multi_urb_write(struct tty_struct *tty,
 177         struct usb_serial_port *port, const unsigned char *buf, int count)
 178 {
 179         unsigned long flags;
 180         struct urb *urb;
 181         unsigned char *buffer;
 182         int status;
 183         int towrite;
 184         int bwrite = 0;
 185
 186         dbg("%s - port %d", __func__, port->number);
 187
 188         if (count == 0)
 189                 dbg("%s - write request of 0 bytes", __func__);
 190
 191         while (count > 0) {
 192                 towrite = (count > port->bulk_out_size) ?
 193                         port->bulk_out_size : count;
 194                 spin_lock_irqsave(&port->lock, flags);
 195                 if (port->urbs_in_flight >
 196                     port->serial->type->max_in_flight_urbs) {
 197                         spin_unlock_irqrestore(&port->lock, flags);
 198                         dbg("%s - write limit hit", __func__);
 199                         return bwrite;
 200                 }
 201                 port->tx_bytes_flight += towrite;
 202                 port->urbs_in_flight++;
 203                 spin_unlock_irqrestore(&port->lock, flags);
 204
 205                 buffer = kmalloc(towrite, GFP_ATOMIC);
 206                 if (!buffer) {
 207                         dev_err(&port->dev,
 208                         "%s ran out of kernel memory for urb ...\n", __func__);
 209                         goto error_no_buffer;
 210                 }
 211
 212                 urb = usb_alloc_urb(0, GFP_ATOMIC);
 213                 if (!urb) {
 214                         dev_err(&port->dev, "%s - no more free urbs\n",
 215                                 __func__);
 216                         goto error_no_urb;
 217                 }
 218
 219                 /* Copy data */
 220                 memcpy(buffer, buf + bwrite, towrite);
 221                 usb_serial_debug_data(debug, &port->dev, __func__,
 222                                       towrite, buffer);
 223                 /* fill the buffer and send it */
 224                 usb_fill_bulk_urb(urb, port->serial->dev,
 225                         usb_sndbulkpipe(port->serial->dev,
 226                                         port->bulk_out_endpointAddress),
 227                         buffer, towrite,
 228                         usb_serial_generic_write_bulk_callback, port);
 229
 230                 status = usb_submit_urb(urb, GFP_ATOMIC);
 231                 if (status) {
 232                         dev_err(&port->dev,
 233                                 "%s - failed submitting write urb, error %d\n",
 234                                 __func__, status);
 235                         goto error;
 236                 }
 237
 238                 /* This urb is the responsibility of the host driver now */
 239                 usb_free_urb(urb);
 240                 dbg("%s write: %d", __func__, towrite);
 241                 count -= towrite;
 242                 bwrite += towrite;
 243         }
 244         return bwrite;
 245
 246 error:
 247         usb_free_urb(urb);
 248 error_no_urb:
 249         kfree(buffer);
 250 error_no_buffer:
 251         spin_lock_irqsave(&port->lock, flags);
 252         port->urbs_in_flight--;
 253         port->tx_bytes_flight -= towrite;
 254         spin_unlock_irqrestore(&port->lock, flags);
 255         return bwrite;
 256 }
 257
 258 /**
 259  * usb_serial_generic_write_start - kick off an URB write
 260  * @port:       Pointer to the &struct usb_serial_port data
 261  *
 262  * Returns the number of bytes queued on success. This will be zero if there
 263  * was nothing to send. Otherwise, it returns a negative errno value
 264  */
 265 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 266 {
 267         struct usb_serial *serial = port->serial;
 268         unsigned char *data;
 269         int result;
 270         int count;
 271         unsigned long flags;
 272         bool start_io;
 273
 274         /* Atomically determine whether we can and need to start a USB
 275          * operation. */
 276         spin_lock_irqsave(&port->lock, flags);
 277         if (port->write_urb_busy)
 278                 start_io = false;
 279         else {
 280                 start_io = (kfifo_len(&port->write_fifo) != 0);
 281                 port->write_urb_busy = start_io;
 282         }
 283         spin_unlock_irqrestore(&port->lock, flags);
 284
 285         if (!start_io)
 286                 return 0;
 287
 288         data = port->write_urb->transfer_buffer;
 289         count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
 290         usb_serial_debug_data(debug, &port->dev, __func__, count, data);
 291
 292         /* set up our urb */
 293         usb_fill_bulk_urb(port->write_urb, serial->dev,
 294                            usb_sndbulkpipe(serial->dev,
 295                                 port->bulk_out_endpointAddress),
 296                            port->write_urb->transfer_buffer, count,
 297                            ((serial->type->write_bulk_callback) ?
 298                              serial->type->write_bulk_callback :
 299                              usb_serial_generic_write_bulk_callback),
 300                            port);
 301
 302         /* send the data out the bulk port */
 303         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 304         if (result) {
 305                 dev_err(&port->dev,
 306                         "%s - failed submitting write urb, error %d\n",
 307                                                 __func__, result);
 308                 /* don't have to grab the lock here, as we will
 309                    retry if != 0 */
 310                 port->write_urb_busy = 0;
 311         } else
 312                 result = count;
 313
 314         return result;
 315 }
 316
 317 /**
 318  * usb_serial_generic_write - generic write function for serial USB devices
 319  * @tty:        Pointer to &struct tty_struct for the device
 320  * @port:       Pointer to the &usb_serial_port structure for the device
 321  * @buf:        Pointer to the data to write
 322  * @count:      Number of bytes to write
 323  *
 324  * Returns the number of characters actually written, which may be anything
 325  * from zero to @count. If an error occurs, it returns the negative errno
 326  * value.
 327  */
 328 int usb_serial_generic_write(struct tty_struct *tty,
 329         struct usb_serial_port *port, const unsigned char *buf, int count)
 330 {
 331         struct usb_serial *serial = port->serial;
 332         int result;
 333
 334         dbg("%s - port %d", __func__, port->number);
 335
 336         if (count == 0) {
 337                 dbg("%s - write request of 0 bytes", __func__);
 338                 return 0;
 339         }
 340
 341         /* only do something if we have a bulk out endpoint */
 342         if (!serial->num_bulk_out)
 343                 return 0;
 344
 345         if (serial->type->max_in_flight_urbs)
 346                 return usb_serial_multi_urb_write(tty, port,
 347                                                   buf, count);
 348
 349         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 350         result = usb_serial_generic_write_start(port);
 351
 352         if (result >= 0)
 353                 result = count;
 354
 355         return result;
 356 }
 357 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 358
 359 int usb_serial_generic_write_room(struct tty_struct *tty)
 360 {
 361         struct usb_serial_port *port = tty->driver_data;
 362         struct usb_serial *serial = port->serial;
 363         unsigned long flags;
 364         int room = 0;
 365
 366         dbg("%s - port %d", __func__, port->number);
 367         spin_lock_irqsave(&port->lock, flags);
 368         if (serial->type->max_in_flight_urbs) {
 369                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
 370                         room = port->bulk_out_size *
 371                                 (serial->type->max_in_flight_urbs -
 372                                  port->urbs_in_flight);
 373         } else if (serial->num_bulk_out)
 374                 room = kfifo_avail(&port->write_fifo);
 375         spin_unlock_irqrestore(&port->lock, flags);
 376
 377         dbg("%s - returns %d", __func__, room);
 378         return room;
 379 }
 380
 381 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 382 {
 383         struct usb_serial_port *port = tty->driver_data;
 384         struct usb_serial *serial = port->serial;
 385         int chars = 0;
 386         unsigned long flags;
 387
 388         dbg("%s - port %d", __func__, port->number);
 389
 390         spin_lock_irqsave(&port->lock, flags);
 391         if (serial->type->max_in_flight_urbs)
 392                 chars = port->tx_bytes_flight;
 393         else if (serial->num_bulk_out)
 394                 chars = kfifo_len(&port->write_fifo);
 395         spin_unlock_irqrestore(&port->lock, flags);
 396
 397         dbg("%s - returns %d", __func__, chars);
 398         return chars;
 399 }
 400
 401
 402 void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
 403                         gfp_t mem_flags)
 404 {
 405         struct urb *urb = port->read_urb;
 406         struct usb_serial *serial = port->serial;
 407         int result;
 408
 409         /* Continue reading from device */
 410         usb_fill_bulk_urb(urb, serial->dev,
 411                            usb_rcvbulkpipe(serial->dev,
 412                                         port->bulk_in_endpointAddress),
 413                            urb->transfer_buffer,
 414                            urb->transfer_buffer_length,
 415                            ((serial->type->read_bulk_callback) ?
 416                              serial->type->read_bulk_callback :
 417                              usb_serial_generic_read_bulk_callback), port);
 418         result = usb_submit_urb(urb, mem_flags);
 419         if (result)
 420                 dev_err(&port->dev,
 421                         "%s - failed resubmitting read urb, error %d\n",
 422                                                         __func__, result);
 423 }
 424 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
 425
 426 /* Push data to tty layer and resubmit the bulk read URB */
 427 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 428 {
 429         struct urb *urb = port->read_urb;
 430         struct tty_struct *tty = tty_port_tty_get(&port->port);
 431         char *ch = (char *)urb->transfer_buffer;
 432         int i;
 433
 434         if (!tty)
 435                 goto done;
 436
 437         /* The per character mucking around with sysrq path it too slow for
 438            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 439            where the USB serial is not a console anyway */
 440         if (!port->console || !port->sysrq)
 441                 tty_insert_flip_string(tty, ch, urb->actual_length);
 442         else {
 443                 /* Push data to tty */
 444                 for (i = 0; i < urb->actual_length; i++, ch++) {
 445                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 446                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 447                 }
 448         }
 449         tty_flip_buffer_push(tty);
 450         tty_kref_put(tty);
 451 done:
 452         usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
 453 }
 454
 455 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 456 {
 457         struct usb_serial_port *port = urb->context;
 458         unsigned char *data = urb->transfer_buffer;
 459         int status = urb->status;
 460         unsigned long flags;
 461
 462         dbg("%s - port %d", __func__, port->number);
 463
 464         if (unlikely(status != 0)) {
 465                 dbg("%s - nonzero read bulk status received: %d",
 466                     __func__, status);
 467                 return;
 468         }
 469
 470         usb_serial_debug_data(debug, &port->dev, __func__,
 471                                                 urb->actual_length, data);
 472
 473         /* Throttle the device if requested by tty */
 474         spin_lock_irqsave(&port->lock, flags);
 475         port->throttled = port->throttle_req;
 476         if (!port->throttled) {
 477                 spin_unlock_irqrestore(&port->lock, flags);
 478                 flush_and_resubmit_read_urb(port);
 479         } else
 480                 spin_unlock_irqrestore(&port->lock, flags);
 481 }
 482 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 483
 484 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 485 {
 486         unsigned long flags;
 487         struct usb_serial_port *port = urb->context;
 488         int status = urb->status;
 489
 490         dbg("%s - port %d", __func__, port->number);
 491
 492         if (port->serial->type->max_in_flight_urbs) {
 493                 kfree(urb->transfer_buffer);
 494
 495                 spin_lock_irqsave(&port->lock, flags);
 496                 --port->urbs_in_flight;
 497                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 498                 if (port->urbs_in_flight < 0)
 499                         port->urbs_in_flight = 0;
 500                 spin_unlock_irqrestore(&port->lock, flags);
 501
 502                 if (status) {
 503                         dbg("%s - nonzero multi-urb write bulk status "
 504                                 "received: %d", __func__, status);
 505                         return;
 506                 }
 507         } else {
 508                 port->write_urb_busy = 0;
 509
 510                 if (status) {
 511                         dbg("%s - nonzero multi-urb write bulk status "
 512                                 "received: %d", __func__, status);
 513                         kfifo_reset_out(&port->write_fifo);
 514                 } else
 515                         usb_serial_generic_write_start(port);
 516         }
 517
 518         usb_serial_port_softint(port);
 519 }
 520 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 521
 522 void usb_serial_generic_throttle(struct tty_struct *tty)
 523 {
 524         struct usb_serial_port *port = tty->driver_data;
 525         unsigned long flags;
 526
 527         dbg("%s - port %d", __func__, port->number);
 528
 529         /* Set the throttle request flag. It will be picked up
 530          * by usb_serial_generic_read_bulk_callback(). */
 531         spin_lock_irqsave(&port->lock, flags);
 532         port->throttle_req = 1;
 533         spin_unlock_irqrestore(&port->lock, flags);
 534 }
 535
 536 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 537 {
 538         struct usb_serial_port *port = tty->driver_data;
 539         int was_throttled;
 540         unsigned long flags;
 541
 542         dbg("%s - port %d", __func__, port->number);
 543
 544         /* Clear the throttle flags */
 545         spin_lock_irqsave(&port->lock, flags);
 546         was_throttled = port->throttled;
 547         port->throttled = port->throttle_req = 0;
 548         spin_unlock_irqrestore(&port->lock, flags);
 549
 550         if (was_throttled) {
 551                 /* Resume reading from device */
 552                 flush_and_resubmit_read_urb(port);
 553         }
 554 }
 555
 556 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 557                         struct usb_serial_port *port, unsigned int ch)
 558 {
 559         if (port->sysrq && port->console) {
 560                 if (ch && time_before(jiffies, port->sysrq)) {
 561                         handle_sysrq(ch, tty);
 562                         port->sysrq = 0;
 563                         return 1;
 564                 }
 565                 port->sysrq = 0;
 566         }
 567         return 0;
 568 }
 569 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 570
 571 int usb_serial_handle_break(struct usb_serial_port *port)
 572 {
 573         if (!port->sysrq) {
 574                 port->sysrq = jiffies + HZ*5;
 575                 return 1;
 576         }
 577         port->sysrq = 0;
 578         return 0;
 579 }
 580 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 581
 582 int usb_serial_generic_resume(struct usb_serial *serial)
 583 {
 584         struct usb_serial_port *port;
 585         int i, c = 0, r;
 586
 587         for (i = 0; i < serial->num_ports; i++) {
 588                 port = serial->port[i];
 589                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 590                         continue;
 591
 592                 if (port->read_urb) {
 593                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 594                         if (r < 0)
 595                                 c++;
 596                 }
 597
 598                 if (port->write_urb) {
 599                         r = usb_serial_generic_write_start(port);
 600                         if (r < 0)
 601                                 c++;
 602                 }
 603         }
 604
 605         return c ? -EIO : 0;
 606 }
 607 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 608
 609 void usb_serial_generic_disconnect(struct usb_serial *serial)
 610 {
 611         int i;
 612
 613         dbg("%s", __func__);
 614
 615         /* stop reads and writes on all ports */
 616         for (i = 0; i < serial->num_ports; ++i)
 617                 generic_cleanup(serial->port[i]);
 618 }
 619
 620 void usb_serial_generic_release(struct usb_serial *serial)
 621 {
 622         dbg("%s", __func__);
 623 }