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         if (timeout)
 265                 period = min_t(unsigned long, period, timeout);
 266
 267         dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
 268                                         __func__, jiffies_to_msecs(timeout),
 269                                         jiffies_to_msecs(period));
 270         expire = jiffies + timeout;
 271         while (!port->serial->type->tx_empty(port)) {
 272                 schedule_timeout_interruptible(period);
 273                 if (signal_pending(current))
 274                         break;
 275                 if (timeout && time_after(jiffies, expire))
 276                         break;
 277         }
 278 }
 279 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
 280
 281 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 282                                                 int index, gfp_t mem_flags)
 283 {
 284         int res;
 285
 286         if (!test_and_clear_bit(index, &port->read_urbs_free))
 287                 return 0;
 288
 289         dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
 290
 291         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 292         if (res) {
 293                 if (res != -EPERM) {
 294                         dev_err(&port->dev,
 295                                         "%s - usb_submit_urb failed: %d\n",
 296                                         __func__, res);
 297                 }
 298                 set_bit(index, &port->read_urbs_free);
 299                 return res;
 300         }
 301
 302         return 0;
 303 }
 304
 305 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 306                                         gfp_t mem_flags)
 307 {
 308         int res;
 309         int i;
 310
 311         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 312                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 313                 if (res)
 314                         goto err;
 315         }
 316
 317         return 0;
 318 err:
 319         for (; i >= 0; --i)
 320                 usb_kill_urb(port->read_urbs[i]);
 321
 322         return res;
 323 }
 324 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 325
 326 void usb_serial_generic_process_read_urb(struct urb *urb)
 327 {
 328         struct usb_serial_port *port = urb->context;
 329         char *ch = (char *)urb->transfer_buffer;
 330         int i;
 331
 332         if (!urb->actual_length)
 333                 return;
 334
 335         /* The per character mucking around with sysrq path it too slow for
 336            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 337            where the USB serial is not a console anyway */
 338         if (!port->port.console || !port->sysrq)
 339                 tty_insert_flip_string(&port->port, ch, urb->actual_length);
 340         else {
 341                 for (i = 0; i < urb->actual_length; i++, ch++) {
 342                         if (!usb_serial_handle_sysrq_char(port, *ch))
 343                                 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
 344                 }
 345         }
 346         tty_flip_buffer_push(&port->port);
 347 }
 348 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 349
 350 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 351 {
 352         struct usb_serial_port *port = urb->context;
 353         unsigned char *data = urb->transfer_buffer;
 354         unsigned long flags;
 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         set_bit(i, &port->read_urbs_free);
 362
 363         dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
 364                                                         urb->actual_length);
 365
 366         if (urb->status) {
 367                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 368                         __func__, urb->status);
 369                 return;
 370         }
 371
 372         usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
 373         port->serial->type->process_read_urb(urb);
 374
 375         /* Throttle the device if requested by tty */
 376         spin_lock_irqsave(&port->lock, flags);
 377         port->throttled = port->throttle_req;
 378         if (!port->throttled) {
 379                 spin_unlock_irqrestore(&port->lock, flags);
 380                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 381         } else
 382                 spin_unlock_irqrestore(&port->lock, flags);
 383 }
 384 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 385
 386 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 387 {
 388         unsigned long flags;
 389         struct usb_serial_port *port = urb->context;
 390         int status = urb->status;
 391         int i;
 392
 393         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 394                 if (port->write_urbs[i] == urb)
 395                         break;
 396
 397         spin_lock_irqsave(&port->lock, flags);
 398         port->tx_bytes -= urb->transfer_buffer_length;
 399         set_bit(i, &port->write_urbs_free);
 400         spin_unlock_irqrestore(&port->lock, flags);
 401
 402         if (status) {
 403                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 404                         __func__, status);
 405
 406                 spin_lock_irqsave(&port->lock, flags);
 407                 kfifo_reset_out(&port->write_fifo);
 408                 spin_unlock_irqrestore(&port->lock, flags);
 409         } else {
 410                 usb_serial_generic_write_start(port);
 411         }
 412
 413         usb_serial_port_softint(port);
 414 }
 415 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 416
 417 void usb_serial_generic_throttle(struct tty_struct *tty)
 418 {
 419         struct usb_serial_port *port = tty->driver_data;
 420         unsigned long flags;
 421
 422         /* Set the throttle request flag. It will be picked up
 423          * by usb_serial_generic_read_bulk_callback(). */
 424         spin_lock_irqsave(&port->lock, flags);
 425         port->throttle_req = 1;
 426         spin_unlock_irqrestore(&port->lock, flags);
 427 }
 428 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 429
 430 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 431 {
 432         struct usb_serial_port *port = tty->driver_data;
 433         int was_throttled;
 434
 435         /* Clear the throttle flags */
 436         spin_lock_irq(&port->lock);
 437         was_throttled = port->throttled;
 438         port->throttled = port->throttle_req = 0;
 439         spin_unlock_irq(&port->lock);
 440
 441         if (was_throttled)
 442                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 443 }
 444 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 445
 446 static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
 447                                 unsigned long arg, struct async_icount *cprev)
 448 {
 449         struct usb_serial_port *port = tty->driver_data;
 450         struct async_icount cnow;
 451         unsigned long flags;
 452         bool ret;
 453
 454         /*
 455          * Use tty-port initialised flag to detect all hangups including the
 456          * one generated at USB-device disconnect.
 457          *
 458          * FIXME: Remove hupping check once tty_port_hangup calls shutdown
 459          *        (which clears the initialised flag) before wake up.
 460          */
 461         if (test_bit(TTY_HUPPING, &tty->flags))
 462                 return true;
 463         if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 464                 return true;
 465
 466         spin_lock_irqsave(&port->lock, flags);
 467         cnow = port->icount;                            /* atomic copy*/
 468         spin_unlock_irqrestore(&port->lock, flags);
 469
 470         ret =   ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
 471                 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
 472                 ((arg & TIOCM_CD)  && (cnow.dcd != cprev->dcd)) ||
 473                 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
 474
 475         *cprev = cnow;
 476
 477         return ret;
 478 }
 479
 480 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
 481 {
 482         struct usb_serial_port *port = tty->driver_data;
 483         struct async_icount cnow;
 484         unsigned long flags;
 485         int ret;
 486
 487         spin_lock_irqsave(&port->lock, flags);
 488         cnow = port->icount;                            /* atomic copy */
 489         spin_unlock_irqrestore(&port->lock, flags);
 490
 491         ret = wait_event_interruptible(port->port.delta_msr_wait,
 492                         usb_serial_generic_msr_changed(tty, arg, &cnow));
 493         if (!ret) {
 494                 if (test_bit(TTY_HUPPING, &tty->flags))
 495                         ret = -EIO;
 496                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 497                         ret = -EIO;
 498         }
 499
 500         return ret;
 501 }
 502 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
 503
 504 int usb_serial_generic_get_icount(struct tty_struct *tty,
 505                                         struct serial_icounter_struct *icount)
 506 {
 507         struct usb_serial_port *port = tty->driver_data;
 508         struct async_icount cnow;
 509         unsigned long flags;
 510
 511         spin_lock_irqsave(&port->lock, flags);
 512         cnow = port->icount;                            /* atomic copy */
 513         spin_unlock_irqrestore(&port->lock, flags);
 514
 515         icount->cts = cnow.cts;
 516         icount->dsr = cnow.dsr;
 517         icount->rng = cnow.rng;
 518         icount->dcd = cnow.dcd;
 519         icount->tx = cnow.tx;
 520         icount->rx = cnow.rx;
 521         icount->frame = cnow.frame;
 522         icount->parity = cnow.parity;
 523         icount->overrun = cnow.overrun;
 524         icount->brk = cnow.brk;
 525         icount->buf_overrun = cnow.buf_overrun;
 526
 527         return 0;
 528 }
 529 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
 530
 531 #ifdef CONFIG_MAGIC_SYSRQ
 532 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 533 {
 534         if (port->sysrq && port->port.console) {
 535                 if (ch && time_before(jiffies, port->sysrq)) {
 536                         handle_sysrq(ch);
 537                         port->sysrq = 0;
 538                         return 1;
 539                 }
 540                 port->sysrq = 0;
 541         }
 542         return 0;
 543 }
 544 #else
 545 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 546 {
 547         return 0;
 548 }
 549 #endif
 550 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 551
 552 int usb_serial_handle_break(struct usb_serial_port *port)
 553 {
 554         if (!port->sysrq) {
 555                 port->sysrq = jiffies + HZ*5;
 556                 return 1;
 557         }
 558         port->sysrq = 0;
 559         return 0;
 560 }
 561 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 562
 563 /**
 564  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 565  *      @port: usb_serial_port structure for the open port
 566  *      @tty: tty_struct structure for the port
 567  *      @status: new carrier detect status, nonzero if active
 568  */
 569 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 570                                 struct tty_struct *tty, unsigned int status)
 571 {
 572         struct tty_port *port = &usb_port->port;
 573
 574         dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
 575
 576         if (status)
 577                 wake_up_interruptible(&port->open_wait);
 578         else if (tty && !C_CLOCAL(tty))
 579                 tty_hangup(tty);
 580 }
 581 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 582
 583 int usb_serial_generic_resume(struct usb_serial *serial)
 584 {
 585         struct usb_serial_port *port;
 586         int i, c = 0, r;
 587
 588         for (i = 0; i < serial->num_ports; i++) {
 589                 port = serial->port[i];
 590                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 591                         continue;
 592
 593                 if (port->bulk_in_size) {
 594                         r = usb_serial_generic_submit_read_urbs(port,
 595                                                                 GFP_NOIO);
 596                         if (r < 0)
 597                                 c++;
 598                 }
 599
 600                 if (port->bulk_out_size) {
 601                         r = usb_serial_generic_write_start(port);
 602                         if (r < 0)
 603                                 c++;
 604                 }
 605         }
 606
 607         return c ? -EIO : 0;
 608 }
 609 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);