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          * Try sending off another urb, unless called from completion handler
 178          * (in which case there will be no free urb or no data).
 179          */
 180         if (mem_flags != GFP_ATOMIC)
 181                 goto retry;
 182
 183         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 184
 185         return 0;
 186 }
 187 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start);
 188
 189 /**
 190  * usb_serial_generic_write - generic write function
 191  * @tty: tty for the port
 192  * @port: usb-serial port
 193  * @buf: data to write
 194  * @count: number of bytes to write
 195  *
 196  * Return: The number of characters buffered, which may be anything from
 197  * zero to @count, or a negative errno value.
 198  */
 199 int usb_serial_generic_write(struct tty_struct *tty,
 200         struct usb_serial_port *port, const unsigned char *buf, int count)
 201 {
 202         int result;
 203
 204         if (!port->bulk_out_size)
 205                 return -ENODEV;
 206
 207         if (!count)
 208                 return 0;
 209
 210         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 211         result = usb_serial_generic_write_start(port, GFP_KERNEL);
 212         if (result)
 213                 return result;
 214
 215         return count;
 216 }
 217 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 218
 219 int usb_serial_generic_write_room(struct tty_struct *tty)
 220 {
 221         struct usb_serial_port *port = tty->driver_data;
 222         unsigned long flags;
 223         int room;
 224
 225         if (!port->bulk_out_size)
 226                 return 0;
 227
 228         spin_lock_irqsave(&port->lock, flags);
 229         room = kfifo_avail(&port->write_fifo);
 230         spin_unlock_irqrestore(&port->lock, flags);
 231
 232         dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
 233         return room;
 234 }
 235
 236 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 237 {
 238         struct usb_serial_port *port = tty->driver_data;
 239         unsigned long flags;
 240         int chars;
 241
 242         if (!port->bulk_out_size)
 243                 return 0;
 244
 245         spin_lock_irqsave(&port->lock, flags);
 246         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 247         spin_unlock_irqrestore(&port->lock, flags);
 248
 249         dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
 250         return chars;
 251 }
 252 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
 253
 254 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
 255 {
 256         struct usb_serial_port *port = tty->driver_data;
 257         unsigned int bps;
 258         unsigned long period;
 259         unsigned long expire;
 260
 261         bps = tty_get_baud_rate(tty);
 262         if (!bps)
 263                 bps = 9600;     /* B0 */
 264         /*
 265          * Use a poll-period of roughly the time it takes to send one
 266          * character or at least one jiffy.
 267          */
 268         period = max_t(unsigned long, (10 * HZ / bps), 1);
 269         period = min_t(unsigned long, period, timeout);
 270
 271         dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
 272                                         __func__, jiffies_to_msecs(timeout),
 273                                         jiffies_to_msecs(period));
 274         expire = jiffies + timeout;
 275         while (!port->serial->type->tx_empty(port)) {
 276                 schedule_timeout_interruptible(period);
 277                 if (signal_pending(current))
 278                         break;
 279                 if (time_after(jiffies, expire))
 280                         break;
 281         }
 282 }
 283 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
 284
 285 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 286                                                 int index, gfp_t mem_flags)
 287 {
 288         int res;
 289
 290         if (!test_and_clear_bit(index, &port->read_urbs_free))
 291                 return 0;
 292
 293         dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
 294
 295         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 296         if (res) {
 297                 if (res != -EPERM) {
 298                         dev_err(&port->dev,
 299                                         "%s - usb_submit_urb failed: %d\n",
 300                                         __func__, res);
 301                 }
 302                 set_bit(index, &port->read_urbs_free);
 303                 return res;
 304         }
 305
 306         return 0;
 307 }
 308
 309 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 310                                         gfp_t mem_flags)
 311 {
 312         int res;
 313         int i;
 314
 315         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 316                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 317                 if (res)
 318                         goto err;
 319         }
 320
 321         return 0;
 322 err:
 323         for (; i >= 0; --i)
 324                 usb_kill_urb(port->read_urbs[i]);
 325
 326         return res;
 327 }
 328 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 329
 330 void usb_serial_generic_process_read_urb(struct urb *urb)
 331 {
 332         struct usb_serial_port *port = urb->context;
 333         char *ch = (char *)urb->transfer_buffer;
 334         int i;
 335
 336         if (!urb->actual_length)
 337                 return;
 338         /*
 339          * The per character mucking around with sysrq path it too slow for
 340          * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
 341          * cases where the USB serial is not a console anyway.
 342          */
 343         if (!port->port.console || !port->sysrq)
 344                 tty_insert_flip_string(&port->port, ch, urb->actual_length);
 345         else {
 346                 for (i = 0; i < urb->actual_length; i++, ch++) {
 347                         if (!usb_serial_handle_sysrq_char(port, *ch))
 348                                 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
 349                 }
 350         }
 351         tty_flip_buffer_push(&port->port);
 352 }
 353 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 354
 355 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 356 {
 357         struct usb_serial_port *port = urb->context;
 358         unsigned char *data = urb->transfer_buffer;
 359         unsigned long flags;
 360         int i;
 361
 362         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 363                 if (urb == port->read_urbs[i])
 364                         break;
 365         }
 366         set_bit(i, &port->read_urbs_free);
 367
 368         dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
 369                                                         urb->actual_length);
 370
 371         if (urb->status) {
 372                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 373                         __func__, urb->status);
 374                 return;
 375         }
 376
 377         usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
 378         port->serial->type->process_read_urb(urb);
 379
 380         /* Throttle the device if requested by tty */
 381         spin_lock_irqsave(&port->lock, flags);
 382         port->throttled = port->throttle_req;
 383         if (!port->throttled) {
 384                 spin_unlock_irqrestore(&port->lock, flags);
 385                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 386         } else
 387                 spin_unlock_irqrestore(&port->lock, flags);
 388 }
 389 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 390
 391 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 392 {
 393         unsigned long flags;
 394         struct usb_serial_port *port = urb->context;
 395         int status = urb->status;
 396         int i;
 397
 398         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 399                 if (port->write_urbs[i] == urb)
 400                         break;
 401
 402         spin_lock_irqsave(&port->lock, flags);
 403         port->tx_bytes -= urb->transfer_buffer_length;
 404         set_bit(i, &port->write_urbs_free);
 405         spin_unlock_irqrestore(&port->lock, flags);
 406
 407         if (status) {
 408                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 409                         __func__, status);
 410
 411                 spin_lock_irqsave(&port->lock, flags);
 412                 kfifo_reset_out(&port->write_fifo);
 413                 spin_unlock_irqrestore(&port->lock, flags);
 414         } else {
 415                 usb_serial_generic_write_start(port, GFP_ATOMIC);
 416         }
 417
 418         usb_serial_port_softint(port);
 419 }
 420 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 421
 422 void usb_serial_generic_throttle(struct tty_struct *tty)
 423 {
 424         struct usb_serial_port *port = tty->driver_data;
 425         unsigned long flags;
 426
 427         spin_lock_irqsave(&port->lock, flags);
 428         port->throttle_req = 1;
 429         spin_unlock_irqrestore(&port->lock, flags);
 430 }
 431 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 432
 433 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 434 {
 435         struct usb_serial_port *port = tty->driver_data;
 436         int was_throttled;
 437
 438         spin_lock_irq(&port->lock);
 439         was_throttled = port->throttled;
 440         port->throttled = port->throttle_req = 0;
 441         spin_unlock_irq(&port->lock);
 442
 443         if (was_throttled)
 444                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 445 }
 446 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 447
 448 static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
 449                                 unsigned long arg, struct async_icount *cprev)
 450 {
 451         struct usb_serial_port *port = tty->driver_data;
 452         struct async_icount cnow;
 453         unsigned long flags;
 454         bool ret;
 455
 456         /*
 457          * Use tty-port initialised flag to detect all hangups including the
 458          * one generated at USB-device disconnect.
 459          */
 460         if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 461                 return true;
 462
 463         spin_lock_irqsave(&port->lock, flags);
 464         cnow = port->icount;                            /* atomic copy*/
 465         spin_unlock_irqrestore(&port->lock, flags);
 466
 467         ret =   ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
 468                 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
 469                 ((arg & TIOCM_CD)  && (cnow.dcd != cprev->dcd)) ||
 470                 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
 471
 472         *cprev = cnow;
 473
 474         return ret;
 475 }
 476
 477 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
 478 {
 479         struct usb_serial_port *port = tty->driver_data;
 480         struct async_icount cnow;
 481         unsigned long flags;
 482         int ret;
 483
 484         spin_lock_irqsave(&port->lock, flags);
 485         cnow = port->icount;                            /* atomic copy */
 486         spin_unlock_irqrestore(&port->lock, flags);
 487
 488         ret = wait_event_interruptible(port->port.delta_msr_wait,
 489                         usb_serial_generic_msr_changed(tty, arg, &cnow));
 490         if (!ret && !test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 491                 ret = -EIO;
 492
 493         return ret;
 494 }
 495 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
 496
 497 int usb_serial_generic_get_icount(struct tty_struct *tty,
 498                                         struct serial_icounter_struct *icount)
 499 {
 500         struct usb_serial_port *port = tty->driver_data;
 501         struct async_icount cnow;
 502         unsigned long flags;
 503
 504         spin_lock_irqsave(&port->lock, flags);
 505         cnow = port->icount;                            /* atomic copy */
 506         spin_unlock_irqrestore(&port->lock, flags);
 507
 508         icount->cts = cnow.cts;
 509         icount->dsr = cnow.dsr;
 510         icount->rng = cnow.rng;
 511         icount->dcd = cnow.dcd;
 512         icount->tx = cnow.tx;
 513         icount->rx = cnow.rx;
 514         icount->frame = cnow.frame;
 515         icount->parity = cnow.parity;
 516         icount->overrun = cnow.overrun;
 517         icount->brk = cnow.brk;
 518         icount->buf_overrun = cnow.buf_overrun;
 519
 520         return 0;
 521 }
 522 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
 523
 524 #ifdef CONFIG_MAGIC_SYSRQ
 525 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 526 {
 527         if (port->sysrq && port->port.console) {
 528                 if (ch && time_before(jiffies, port->sysrq)) {
 529                         handle_sysrq(ch);
 530                         port->sysrq = 0;
 531                         return 1;
 532                 }
 533                 port->sysrq = 0;
 534         }
 535         return 0;
 536 }
 537 #else
 538 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 539 {
 540         return 0;
 541 }
 542 #endif
 543 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 544
 545 int usb_serial_handle_break(struct usb_serial_port *port)
 546 {
 547         if (!port->sysrq) {
 548                 port->sysrq = jiffies + HZ*5;
 549                 return 1;
 550         }
 551         port->sysrq = 0;
 552         return 0;
 553 }
 554 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 555
 556 /**
 557  * usb_serial_handle_dcd_change - handle a change of carrier detect state
 558  * @port: usb-serial port
 559  * @tty: tty for the port
 560  * @status: new carrier detect status, nonzero if active
 561  */
 562 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 563                                 struct tty_struct *tty, unsigned int status)
 564 {
 565         struct tty_port *port = &usb_port->port;
 566
 567         dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
 568
 569         if (tty) {
 570                 struct tty_ldisc *ld = tty_ldisc_ref(tty);
 571
 572                 if (ld) {
 573                         if (ld->ops->dcd_change)
 574                                 ld->ops->dcd_change(tty, status);
 575                         tty_ldisc_deref(ld);
 576                 }
 577         }
 578
 579         if (status)
 580                 wake_up_interruptible(&port->open_wait);
 581         else if (tty && !C_CLOCAL(tty))
 582                 tty_hangup(tty);
 583 }
 584 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 585
 586 int usb_serial_generic_resume(struct usb_serial *serial)
 587 {
 588         struct usb_serial_port *port;
 589         int i, c = 0, r;
 590
 591         for (i = 0; i < serial->num_ports; i++) {
 592                 port = serial->port[i];
 593                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 594                         continue;
 595
 596                 if (port->bulk_in_size) {
 597                         r = usb_serial_generic_submit_read_urbs(port,
 598                                                                 GFP_NOIO);
 599                         if (r < 0)
 600                                 c++;
 601                 }
 602
 603                 if (port->bulk_out_size) {
 604                         r = usb_serial_generic_write_start(port, GFP_NOIO);
 605                         if (r < 0)
 606                                 c++;
 607                 }
 608         }
 609
 610         return c ? -EIO : 0;
 611 }
 612 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);