drivers/usb/serial/generic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * USB Serial Converter Generic functions
   4  *
   5  * Copyright (C) 2010 - 2013 Johan Hovold (jhovold@gmail.com)
   6  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/sched/signal.h>
  11 #include <linux/errno.h>
  12 #include <linux/slab.h>
  13 #include <linux/sysrq.h>
  14 #include <linux/tty.h>
  15 #include <linux/tty_flip.h>
  16 #include <linux/module.h>
  17 #include <linux/moduleparam.h>
  18 #include <linux/usb.h>
  19 #include <linux/usb/serial.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/kfifo.h>
  22 #include <linux/serial.h>
  23
  24 #ifdef CONFIG_USB_SERIAL_GENERIC
  25
  26 static __u16 vendor  = 0x05f9;
  27 static __u16 product = 0xffff;
  28
  29 module_param(vendor, ushort, 0);
  30 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  31
  32 module_param(product, ushort, 0);
  33 MODULE_PARM_DESC(product, "User specified USB idProduct");
  34
  35 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  36
  37 static int usb_serial_generic_probe(struct usb_serial *serial,
  38                                         const struct usb_device_id *id)
  39 {
  40         struct device *dev = &serial->interface->dev;
  41
  42         dev_info(dev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n");
  43         dev_info(dev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n");
  44
  45         return 0;
  46 }
  47
  48 static int usb_serial_generic_calc_num_ports(struct usb_serial *serial,
  49                                         struct usb_serial_endpoints *epds)
  50 {
  51         struct device *dev = &serial->interface->dev;
  52         int num_ports;
  53
  54         num_ports = max(epds->num_bulk_in, epds->num_bulk_out);
  55
  56         if (num_ports == 0) {
  57                 dev_err(dev, "device has no bulk endpoints\n");
  58                 return -ENODEV;
  59         }
  60
  61         return num_ports;
  62 }
  63
  64 static struct usb_serial_driver usb_serial_generic_device = {
  65         .driver = {
  66                 .owner =        THIS_MODULE,
  67                 .name =         "generic",
  68         },
  69         .id_table =             generic_device_ids,
  70         .probe =                usb_serial_generic_probe,
  71         .calc_num_ports =       usb_serial_generic_calc_num_ports,
  72         .throttle =             usb_serial_generic_throttle,
  73         .unthrottle =           usb_serial_generic_unthrottle,
  74         .resume =               usb_serial_generic_resume,
  75 };
  76
  77 static struct usb_serial_driver * const serial_drivers[] = {
  78         &usb_serial_generic_device, NULL
  79 };
  80
  81 #endif
  82
  83 int usb_serial_generic_register(void)
  84 {
  85         int retval = 0;
  86
  87 #ifdef CONFIG_USB_SERIAL_GENERIC
  88         generic_device_ids[0].idVendor = vendor;
  89         generic_device_ids[0].idProduct = product;
  90         generic_device_ids[0].match_flags =
  91                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  92
  93         retval = usb_serial_register_drivers(serial_drivers,
  94                         "usbserial_generic", generic_device_ids);
  95 #endif
  96         return retval;
  97 }
  98
  99 void usb_serial_generic_deregister(void)
 100 {
 101 #ifdef CONFIG_USB_SERIAL_GENERIC
 102         usb_serial_deregister_drivers(serial_drivers);
 103 #endif
 104 }
 105
 106 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 107 {
 108         int result = 0;
 109         unsigned long flags;
 110
 111         spin_lock_irqsave(&port->lock, flags);
 112         port->throttled = 0;
 113         port->throttle_req = 0;
 114         spin_unlock_irqrestore(&port->lock, flags);
 115
 116         if (port->bulk_in_size)
 117                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 118
 119         return result;
 120 }
 121 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 122
 123 void usb_serial_generic_close(struct usb_serial_port *port)
 124 {
 125         unsigned long flags;
 126         int i;
 127
 128         if (port->bulk_out_size) {
 129                 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 130                         usb_kill_urb(port->write_urbs[i]);
 131
 132                 spin_lock_irqsave(&port->lock, flags);
 133                 kfifo_reset_out(&port->write_fifo);
 134                 spin_unlock_irqrestore(&port->lock, flags);
 135         }
 136         if (port->bulk_in_size) {
 137                 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 138                         usb_kill_urb(port->read_urbs[i]);
 139         }
 140 }
 141 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 142
 143 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 144                                                 void *dest, size_t size)
 145 {
 146         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 147 }
 148
 149 /**
 150  * usb_serial_generic_write_start - start writing buffered data
 151  * @port: usb-serial port
 152  * @mem_flags: flags to use for memory allocations
 153  *
 154  * Serialised using USB_SERIAL_WRITE_BUSY flag.
 155  *
 156  * Return: Zero on success or if busy, otherwise a negative errno value.
 157  */
 158 int usb_serial_generic_write_start(struct usb_serial_port *port,
 159                                                         gfp_t mem_flags)
 160 {
 161         struct urb *urb;
 162         int count, result;
 163         unsigned long flags;
 164         int i;
 165
 166         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 167                 return 0;
 168 retry:
 169         spin_lock_irqsave(&port->lock, flags);
 170         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 171                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 172                 spin_unlock_irqrestore(&port->lock, flags);
 173                 return 0;
 174         }
 175         i = (int)find_first_bit(&port->write_urbs_free,
 176                                                 ARRAY_SIZE(port->write_urbs));
 177         spin_unlock_irqrestore(&port->lock, flags);
 178
 179         urb = port->write_urbs[i];
 180         count = port->serial->type->prepare_write_buffer(port,
 181                                                 urb->transfer_buffer,
 182                                                 port->bulk_out_size);
 183         urb->transfer_buffer_length = count;
 184         usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
 185         spin_lock_irqsave(&port->lock, flags);
 186         port->tx_bytes += count;
 187         spin_unlock_irqrestore(&port->lock, flags);
 188
 189         clear_bit(i, &port->write_urbs_free);
 190         result = usb_submit_urb(urb, mem_flags);
 191         if (result) {
 192                 dev_err_console(port, "%s - error submitting urb: %d\n",
 193                                                 __func__, result);
 194                 set_bit(i, &port->write_urbs_free);
 195                 spin_lock_irqsave(&port->lock, flags);
 196                 port->tx_bytes -= count;
 197                 spin_unlock_irqrestore(&port->lock, flags);
 198
 199                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 200                 return result;
 201         }
 202
 203         goto retry;     /* try sending off another urb */
 204 }
 205 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start);
 206
 207 /**
 208  * usb_serial_generic_write - generic write function
 209  * @tty: tty for the port
 210  * @port: usb-serial port
 211  * @buf: data to write
 212  * @count: number of bytes to write
 213  *
 214  * Return: The number of characters buffered, which may be anything from
 215  * zero to @count, or a negative errno value.
 216  */
 217 int usb_serial_generic_write(struct tty_struct *tty,
 218         struct usb_serial_port *port, const unsigned char *buf, int count)
 219 {
 220         int result;
 221
 222         if (!port->bulk_out_size)
 223                 return -ENODEV;
 224
 225         if (!count)
 226                 return 0;
 227
 228         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 229         result = usb_serial_generic_write_start(port, GFP_ATOMIC);
 230         if (result)
 231                 return result;
 232
 233         return count;
 234 }
 235 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 236
 237 int usb_serial_generic_write_room(struct tty_struct *tty)
 238 {
 239         struct usb_serial_port *port = tty->driver_data;
 240         unsigned long flags;
 241         int room;
 242
 243         if (!port->bulk_out_size)
 244                 return 0;
 245
 246         spin_lock_irqsave(&port->lock, flags);
 247         room = kfifo_avail(&port->write_fifo);
 248         spin_unlock_irqrestore(&port->lock, flags);
 249
 250         dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
 251         return room;
 252 }
 253
 254 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 255 {
 256         struct usb_serial_port *port = tty->driver_data;
 257         unsigned long flags;
 258         int chars;
 259
 260         if (!port->bulk_out_size)
 261                 return 0;
 262
 263         spin_lock_irqsave(&port->lock, flags);
 264         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 265         spin_unlock_irqrestore(&port->lock, flags);
 266
 267         dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
 268         return chars;
 269 }
 270 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
 271
 272 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
 273 {
 274         struct usb_serial_port *port = tty->driver_data;
 275         unsigned int bps;
 276         unsigned long period;
 277         unsigned long expire;
 278
 279         bps = tty_get_baud_rate(tty);
 280         if (!bps)
 281                 bps = 9600;     /* B0 */
 282         /*
 283          * Use a poll-period of roughly the time it takes to send one
 284          * character or at least one jiffy.
 285          */
 286         period = max_t(unsigned long, (10 * HZ / bps), 1);
 287         if (timeout)
 288                 period = min_t(unsigned long, period, timeout);
 289
 290         dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
 291                                         __func__, jiffies_to_msecs(timeout),
 292                                         jiffies_to_msecs(period));
 293         expire = jiffies + timeout;
 294         while (!port->serial->type->tx_empty(port)) {
 295                 schedule_timeout_interruptible(period);
 296                 if (signal_pending(current))
 297                         break;
 298                 if (timeout && time_after(jiffies, expire))
 299                         break;
 300         }
 301 }
 302 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
 303
 304 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 305                                                 int index, gfp_t mem_flags)
 306 {
 307         int res;
 308
 309         if (!test_and_clear_bit(index, &port->read_urbs_free))
 310                 return 0;
 311
 312         dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
 313
 314         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 315         if (res) {
 316                 if (res != -EPERM && res != -ENODEV) {
 317                         dev_err(&port->dev,
 318                                         "%s - usb_submit_urb failed: %d\n",
 319                                         __func__, res);
 320                 }
 321                 set_bit(index, &port->read_urbs_free);
 322                 return res;
 323         }
 324
 325         return 0;
 326 }
 327
 328 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 329                                         gfp_t mem_flags)
 330 {
 331         int res;
 332         int i;
 333
 334         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 335                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 336                 if (res)
 337                         goto err;
 338         }
 339
 340         return 0;
 341 err:
 342         for (; i >= 0; --i)
 343                 usb_kill_urb(port->read_urbs[i]);
 344
 345         return res;
 346 }
 347 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 348
 349 void usb_serial_generic_process_read_urb(struct urb *urb)
 350 {
 351         struct usb_serial_port *port = urb->context;
 352         char *ch = (char *)urb->transfer_buffer;
 353         int i;
 354
 355         if (!urb->actual_length)
 356                 return;
 357         /*
 358          * The per character mucking around with sysrq path it too slow for
 359          * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
 360          * cases where the USB serial is not a console anyway.
 361          */
 362         if (!port->port.console || !port->sysrq) {
 363                 tty_insert_flip_string(&port->port, ch, urb->actual_length);
 364         } else {
 365                 for (i = 0; i < urb->actual_length; i++, ch++) {
 366                         if (!usb_serial_handle_sysrq_char(port, *ch))
 367                                 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
 368                 }
 369         }
 370         tty_flip_buffer_push(&port->port);
 371 }
 372 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 373
 374 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 375 {
 376         struct usb_serial_port *port = urb->context;
 377         unsigned char *data = urb->transfer_buffer;
 378         unsigned long flags;
 379         bool stopped = false;
 380         int status = urb->status;
 381         int i;
 382
 383         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 384                 if (urb == port->read_urbs[i])
 385                         break;
 386         }
 387
 388         dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
 389                                                         urb->actual_length);
 390         switch (status) {
 391         case 0:
 392                 usb_serial_debug_data(&port->dev, __func__, urb->actual_length,
 393                                                         data);
 394                 port->serial->type->process_read_urb(urb);
 395                 break;
 396         case -ENOENT:
 397         case -ECONNRESET:
 398         case -ESHUTDOWN:
 399                 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
 400                                                         __func__, status);
 401                 stopped = true;
 402                 break;
 403         case -EPIPE:
 404                 dev_err(&port->dev, "%s - urb stopped: %d\n",
 405                                                         __func__, status);
 406                 stopped = true;
 407                 break;
 408         default:
 409                 dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
 410                                                         __func__, status);
 411                 break;
 412         }
 413
 414         /*
 415          * Make sure URB processing is done before marking as free to avoid
 416          * racing with unthrottle() on another CPU. Matches the barriers
 417          * implied by the test_and_clear_bit() in
 418          * usb_serial_generic_submit_read_urb().
 419          */
 420         smp_mb__before_atomic();
 421         set_bit(i, &port->read_urbs_free);
 422         /*
 423          * Make sure URB is marked as free before checking the throttled flag
 424          * to avoid racing with unthrottle() on another CPU. Matches the
 425          * smp_mb() in unthrottle().
 426          */
 427         smp_mb__after_atomic();
 428
 429         if (stopped)
 430                 return;
 431
 432         /* Throttle the device if requested by tty */
 433         spin_lock_irqsave(&port->lock, flags);
 434         port->throttled = port->throttle_req;
 435         if (!port->throttled) {
 436                 spin_unlock_irqrestore(&port->lock, flags);
 437                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 438         } else {
 439                 spin_unlock_irqrestore(&port->lock, flags);
 440         }
 441 }
 442 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 443
 444 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 445 {
 446         unsigned long flags;
 447         struct usb_serial_port *port = urb->context;
 448         int status = urb->status;
 449         int i;
 450
 451         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
 452                 if (port->write_urbs[i] == urb)
 453                         break;
 454         }
 455         spin_lock_irqsave(&port->lock, flags);
 456         port->tx_bytes -= urb->transfer_buffer_length;
 457         set_bit(i, &port->write_urbs_free);
 458         spin_unlock_irqrestore(&port->lock, flags);
 459
 460         switch (status) {
 461         case 0:
 462                 break;
 463         case -ENOENT:
 464         case -ECONNRESET:
 465         case -ESHUTDOWN:
 466                 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
 467                                                         __func__, status);
 468                 return;
 469         case -EPIPE:
 470                 dev_err_console(port, "%s - urb stopped: %d\n",
 471                                                         __func__, status);
 472                 return;
 473         default:
 474                 dev_err_console(port, "%s - nonzero urb status: %d\n",
 475                                                         __func__, status);
 476                 goto resubmit;
 477         }
 478
 479 resubmit:
 480         usb_serial_generic_write_start(port, GFP_ATOMIC);
 481         usb_serial_port_softint(port);
 482 }
 483 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 484
 485 void usb_serial_generic_throttle(struct tty_struct *tty)
 486 {
 487         struct usb_serial_port *port = tty->driver_data;
 488         unsigned long flags;
 489
 490         spin_lock_irqsave(&port->lock, flags);
 491         port->throttle_req = 1;
 492         spin_unlock_irqrestore(&port->lock, flags);
 493 }
 494 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 495
 496 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 497 {
 498         struct usb_serial_port *port = tty->driver_data;
 499         int was_throttled;
 500
 501         spin_lock_irq(&port->lock);
 502         was_throttled = port->throttled;
 503         port->throttled = port->throttle_req = 0;
 504         spin_unlock_irq(&port->lock);
 505
 506         /*
 507          * Matches the smp_mb__after_atomic() in
 508          * usb_serial_generic_read_bulk_callback().
 509          */
 510         smp_mb();
 511
 512         if (was_throttled)
 513                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 514 }
 515 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 516
 517 static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
 518                                 unsigned long arg, struct async_icount *cprev)
 519 {
 520         struct usb_serial_port *port = tty->driver_data;
 521         struct async_icount cnow;
 522         unsigned long flags;
 523         bool ret;
 524
 525         /*
 526          * Use tty-port initialised flag to detect all hangups including the
 527          * one generated at USB-device disconnect.
 528          */
 529         if (!tty_port_initialized(&port->port))
 530                 return true;
 531
 532         spin_lock_irqsave(&port->lock, flags);
 533         cnow = port->icount;                            /* atomic copy*/
 534         spin_unlock_irqrestore(&port->lock, flags);
 535
 536         ret =   ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
 537                 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
 538                 ((arg & TIOCM_CD)  && (cnow.dcd != cprev->dcd)) ||
 539                 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
 540
 541         *cprev = cnow;
 542
 543         return ret;
 544 }
 545
 546 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
 547 {
 548         struct usb_serial_port *port = tty->driver_data;
 549         struct async_icount cnow;
 550         unsigned long flags;
 551         int ret;
 552
 553         spin_lock_irqsave(&port->lock, flags);
 554         cnow = port->icount;                            /* atomic copy */
 555         spin_unlock_irqrestore(&port->lock, flags);
 556
 557         ret = wait_event_interruptible(port->port.delta_msr_wait,
 558                         usb_serial_generic_msr_changed(tty, arg, &cnow));
 559         if (!ret && !tty_port_initialized(&port->port))
 560                 ret = -EIO;
 561
 562         return ret;
 563 }
 564 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
 565
 566 int usb_serial_generic_get_icount(struct tty_struct *tty,
 567                                         struct serial_icounter_struct *icount)
 568 {
 569         struct usb_serial_port *port = tty->driver_data;
 570         struct async_icount cnow;
 571         unsigned long flags;
 572
 573         spin_lock_irqsave(&port->lock, flags);
 574         cnow = port->icount;                            /* atomic copy */
 575         spin_unlock_irqrestore(&port->lock, flags);
 576
 577         icount->cts = cnow.cts;
 578         icount->dsr = cnow.dsr;
 579         icount->rng = cnow.rng;
 580         icount->dcd = cnow.dcd;
 581         icount->tx = cnow.tx;
 582         icount->rx = cnow.rx;
 583         icount->frame = cnow.frame;
 584         icount->parity = cnow.parity;
 585         icount->overrun = cnow.overrun;
 586         icount->brk = cnow.brk;
 587         icount->buf_overrun = cnow.buf_overrun;
 588
 589         return 0;
 590 }
 591 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
 592
 593 #ifdef CONFIG_MAGIC_SYSRQ
 594 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 595 {
 596         if (port->sysrq && port->port.console) {
 597                 if (ch && time_before(jiffies, port->sysrq)) {
 598                         handle_sysrq(ch);
 599                         port->sysrq = 0;
 600                         return 1;
 601                 }
 602                 port->sysrq = 0;
 603         }
 604         return 0;
 605 }
 606 #else
 607 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 608 {
 609         return 0;
 610 }
 611 #endif
 612 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 613
 614 int usb_serial_handle_break(struct usb_serial_port *port)
 615 {
 616         if (!port->sysrq) {
 617                 port->sysrq = jiffies + HZ*5;
 618                 return 1;
 619         }
 620         port->sysrq = 0;
 621         return 0;
 622 }
 623 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 624
 625 /**
 626  * usb_serial_handle_dcd_change - handle a change of carrier detect state
 627  * @port: usb-serial port
 628  * @tty: tty for the port
 629  * @status: new carrier detect status, nonzero if active
 630  */
 631 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 632                                 struct tty_struct *tty, unsigned int status)
 633 {
 634         struct tty_port *port = &usb_port->port;
 635
 636         dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
 637
 638         if (tty) {
 639                 struct tty_ldisc *ld = tty_ldisc_ref(tty);
 640
 641                 if (ld) {
 642                         if (ld->ops->dcd_change)
 643                                 ld->ops->dcd_change(tty, status);
 644                         tty_ldisc_deref(ld);
 645                 }
 646         }
 647
 648         if (status)
 649                 wake_up_interruptible(&port->open_wait);
 650         else if (tty && !C_CLOCAL(tty))
 651                 tty_hangup(tty);
 652 }
 653 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 654
 655 int usb_serial_generic_resume(struct usb_serial *serial)
 656 {
 657         struct usb_serial_port *port;
 658         int i, c = 0, r;
 659
 660         for (i = 0; i < serial->num_ports; i++) {
 661                 port = serial->port[i];
 662                 if (!tty_port_initialized(&port->port))
 663                         continue;
 664
 665                 if (port->bulk_in_size) {
 666                         r = usb_serial_generic_submit_read_urbs(port,
 667                                                                 GFP_NOIO);
 668                         if (r < 0)
 669                                 c++;
 670                 }
 671
 672                 if (port->bulk_out_size) {
 673                         r = usb_serial_generic_write_start(port, GFP_NOIO);
 674                         if (r < 0)
 675                                 c++;
 676                 }
 677         }
 678
 679         return c ? -EIO : 0;
 680 }
 681 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);