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