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 (port->bulk_in_size) {
 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 transfers that might be going on */
 163                 if (port->bulk_out_size)
 164                         usb_kill_urb(port->write_urb);
 165                 if (port->bulk_in_size)
 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         /* only do something if we have a bulk out endpoint */
 337         if (!port->bulk_out_size)
 338                 return -ENODEV;
 339
 340         if (count == 0) {
 341                 dbg("%s - write request of 0 bytes", __func__);
 342                 return 0;
 343         }
 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
 368         if (!port->bulk_out_size)
 369                 return 0;
 370
 371         spin_lock_irqsave(&port->lock, flags);
 372         if (serial->type->max_in_flight_urbs) {
 373                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
 374                         room = port->bulk_out_size *
 375                                 (serial->type->max_in_flight_urbs -
 376                                  port->urbs_in_flight);
 377         } else {
 378                 room = kfifo_avail(&port->write_fifo);
 379         }
 380         spin_unlock_irqrestore(&port->lock, flags);
 381
 382         dbg("%s - returns %d", __func__, room);
 383         return room;
 384 }
 385
 386 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 387 {
 388         struct usb_serial_port *port = tty->driver_data;
 389         struct usb_serial *serial = port->serial;
 390         unsigned long flags;
 391         int chars;
 392
 393         dbg("%s - port %d", __func__, port->number);
 394
 395         if (!port->bulk_out_size)
 396                 return 0;
 397
 398         spin_lock_irqsave(&port->lock, flags);
 399         if (serial->type->max_in_flight_urbs)
 400                 chars = port->tx_bytes_flight;
 401         else
 402                 chars = kfifo_len(&port->write_fifo);
 403         spin_unlock_irqrestore(&port->lock, flags);
 404
 405         dbg("%s - returns %d", __func__, chars);
 406         return chars;
 407 }
 408
 409
 410 void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
 411                         gfp_t mem_flags)
 412 {
 413         struct urb *urb = port->read_urb;
 414         struct usb_serial *serial = port->serial;
 415         int result;
 416
 417         /* Continue reading from device */
 418         usb_fill_bulk_urb(urb, serial->dev,
 419                            usb_rcvbulkpipe(serial->dev,
 420                                         port->bulk_in_endpointAddress),
 421                            urb->transfer_buffer,
 422                            urb->transfer_buffer_length,
 423                            ((serial->type->read_bulk_callback) ?
 424                              serial->type->read_bulk_callback :
 425                              usb_serial_generic_read_bulk_callback), port);
 426
 427         result = usb_submit_urb(urb, mem_flags);
 428         if (result && result != -EPERM) {
 429                 dev_err(&port->dev,
 430                         "%s - failed resubmitting read urb, error %d\n",
 431                                                         __func__, result);
 432         }
 433 }
 434 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
 435
 436 /* Push data to tty layer and resubmit the bulk read URB */
 437 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 438 {
 439         struct urb *urb = port->read_urb;
 440         struct tty_struct *tty = tty_port_tty_get(&port->port);
 441         char *ch = (char *)urb->transfer_buffer;
 442         int i;
 443
 444         if (!tty)
 445                 goto done;
 446
 447         /* The per character mucking around with sysrq path it too slow for
 448            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 449            where the USB serial is not a console anyway */
 450         if (!port->console || !port->sysrq)
 451                 tty_insert_flip_string(tty, ch, urb->actual_length);
 452         else {
 453                 /* Push data to tty */
 454                 for (i = 0; i < urb->actual_length; i++, ch++) {
 455                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 456                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 457                 }
 458         }
 459         tty_flip_buffer_push(tty);
 460         tty_kref_put(tty);
 461 done:
 462         usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
 463 }
 464
 465 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 466 {
 467         struct usb_serial_port *port = urb->context;
 468         unsigned char *data = urb->transfer_buffer;
 469         int status = urb->status;
 470         unsigned long flags;
 471
 472         dbg("%s - port %d", __func__, port->number);
 473
 474         if (unlikely(status != 0)) {
 475                 dbg("%s - nonzero read bulk status received: %d",
 476                     __func__, status);
 477                 return;
 478         }
 479
 480         usb_serial_debug_data(debug, &port->dev, __func__,
 481                                                 urb->actual_length, data);
 482
 483         /* Throttle the device if requested by tty */
 484         spin_lock_irqsave(&port->lock, flags);
 485         port->throttled = port->throttle_req;
 486         if (!port->throttled) {
 487                 spin_unlock_irqrestore(&port->lock, flags);
 488                 flush_and_resubmit_read_urb(port);
 489         } else
 490                 spin_unlock_irqrestore(&port->lock, flags);
 491 }
 492 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 493
 494 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 495 {
 496         unsigned long flags;
 497         struct usb_serial_port *port = urb->context;
 498         int status = urb->status;
 499
 500         dbg("%s - port %d", __func__, port->number);
 501
 502         if (port->serial->type->max_in_flight_urbs) {
 503                 kfree(urb->transfer_buffer);
 504
 505                 spin_lock_irqsave(&port->lock, flags);
 506                 --port->urbs_in_flight;
 507                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 508                 if (port->urbs_in_flight < 0)
 509                         port->urbs_in_flight = 0;
 510                 spin_unlock_irqrestore(&port->lock, flags);
 511         } else {
 512                 port->write_urb_busy = 0;
 513
 514                 if (status)
 515                         kfifo_reset_out(&port->write_fifo);
 516                 else
 517                         usb_serial_generic_write_start(port);
 518         }
 519
 520         if (status)
 521                 dbg("%s - non-zero urb status: %d", __func__, status);
 522
 523         usb_serial_port_softint(port);
 524 }
 525 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 526
 527 void usb_serial_generic_throttle(struct tty_struct *tty)
 528 {
 529         struct usb_serial_port *port = tty->driver_data;
 530         unsigned long flags;
 531
 532         dbg("%s - port %d", __func__, port->number);
 533
 534         /* Set the throttle request flag. It will be picked up
 535          * by usb_serial_generic_read_bulk_callback(). */
 536         spin_lock_irqsave(&port->lock, flags);
 537         port->throttle_req = 1;
 538         spin_unlock_irqrestore(&port->lock, flags);
 539 }
 540
 541 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 542 {
 543         struct usb_serial_port *port = tty->driver_data;
 544         int was_throttled;
 545         unsigned long flags;
 546
 547         dbg("%s - port %d", __func__, port->number);
 548
 549         /* Clear the throttle flags */
 550         spin_lock_irqsave(&port->lock, flags);
 551         was_throttled = port->throttled;
 552         port->throttled = port->throttle_req = 0;
 553         spin_unlock_irqrestore(&port->lock, flags);
 554
 555         if (was_throttled) {
 556                 /* Resume reading from device */
 557                 flush_and_resubmit_read_urb(port);
 558         }
 559 }
 560
 561 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 562                         struct usb_serial_port *port, unsigned int ch)
 563 {
 564         if (port->sysrq && port->console) {
 565                 if (ch && time_before(jiffies, port->sysrq)) {
 566                         handle_sysrq(ch, tty);
 567                         port->sysrq = 0;
 568                         return 1;
 569                 }
 570                 port->sysrq = 0;
 571         }
 572         return 0;
 573 }
 574 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 575
 576 int usb_serial_handle_break(struct usb_serial_port *port)
 577 {
 578         if (!port->sysrq) {
 579                 port->sysrq = jiffies + HZ*5;
 580                 return 1;
 581         }
 582         port->sysrq = 0;
 583         return 0;
 584 }
 585 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 586
 587 int usb_serial_generic_resume(struct usb_serial *serial)
 588 {
 589         struct usb_serial_port *port;
 590         int i, c = 0, r;
 591
 592         for (i = 0; i < serial->num_ports; i++) {
 593                 port = serial->port[i];
 594                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 595                         continue;
 596
 597                 if (port->read_urb) {
 598                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 599                         if (r < 0)
 600                                 c++;
 601                 }
 602
 603                 if (port->write_urb) {
 604                         r = usb_serial_generic_write_start(port);
 605                         if (r < 0)
 606                                 c++;
 607                 }
 608         }
 609
 610         return c ? -EIO : 0;
 611 }
 612 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 613
 614 void usb_serial_generic_disconnect(struct usb_serial *serial)
 615 {
 616         int i;
 617
 618         dbg("%s", __func__);
 619
 620         /* stop reads and writes on all ports */
 621         for (i = 0; i < serial->num_ports; ++i)
 622                 generic_cleanup(serial->port[i]);
 623 }
 624
 625 void usb_serial_generic_release(struct usb_serial *serial)
 626 {
 627         dbg("%s", __func__);
 628 }