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