drivers/usb/serial/generic.c

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