drivers/usb/serial/generic.c

   1 /*
   2  * USB Serial Converter Generic functions
   3  *
   4  * Copyright (C) 2010 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 static int debug;
  28
  29 #define MAX_TX_URBS             40
  30
  31 #ifdef CONFIG_USB_SERIAL_GENERIC
  32
  33 static int generic_probe(struct usb_interface *interface,
  34                          const struct usb_device_id *id);
  35
  36 static __u16 vendor  = 0x05f9;
  37 static __u16 product = 0xffff;
  38
  39 module_param(vendor, ushort, 0);
  40 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  41
  42 module_param(product, ushort, 0);
  43 MODULE_PARM_DESC(product, "User specified USB idProduct");
  44
  45 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  46
  47 /* we want to look at all devices, as the vendor/product id can change
  48  * depending on the command line argument */
  49 static const struct usb_device_id generic_serial_ids[] = {
  50         {.driver_info = 42},
  51         {}
  52 };
  53
  54 static struct usb_driver generic_driver = {
  55         .name =         "usbserial_generic",
  56         .probe =        generic_probe,
  57         .disconnect =   usb_serial_disconnect,
  58         .id_table =     generic_serial_ids,
  59         .no_dynamic_id =        1,
  60 };
  61
  62 /* All of the device info needed for the Generic Serial Converter */
  63 struct usb_serial_driver usb_serial_generic_device = {
  64         .driver = {
  65                 .owner =        THIS_MODULE,
  66                 .name =         "generic",
  67         },
  68         .id_table =             generic_device_ids,
  69         .usb_driver =           &generic_driver,
  70         .num_ports =            1,
  71         .disconnect =           usb_serial_generic_disconnect,
  72         .release =              usb_serial_generic_release,
  73         .throttle =             usb_serial_generic_throttle,
  74         .unthrottle =           usb_serial_generic_unthrottle,
  75         .resume =               usb_serial_generic_resume,
  76 };
  77
  78 static int generic_probe(struct usb_interface *interface,
  79                                const struct usb_device_id *id)
  80 {
  81         const struct usb_device_id *id_pattern;
  82
  83         id_pattern = usb_match_id(interface, generic_device_ids);
  84         if (id_pattern != NULL)
  85                 return usb_serial_probe(interface, id);
  86         return -ENODEV;
  87 }
  88 #endif
  89
  90 int usb_serial_generic_register(int _debug)
  91 {
  92         int retval = 0;
  93
  94         debug = _debug;
  95 #ifdef CONFIG_USB_SERIAL_GENERIC
  96         generic_device_ids[0].idVendor = vendor;
  97         generic_device_ids[0].idProduct = product;
  98         generic_device_ids[0].match_flags =
  99                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
 100
 101         /* register our generic driver with ourselves */
 102         retval = usb_serial_register(&usb_serial_generic_device);
 103         if (retval)
 104                 goto exit;
 105         retval = usb_register(&generic_driver);
 106         if (retval)
 107                 usb_serial_deregister(&usb_serial_generic_device);
 108 exit:
 109 #endif
 110         return retval;
 111 }
 112
 113 void usb_serial_generic_deregister(void)
 114 {
 115 #ifdef CONFIG_USB_SERIAL_GENERIC
 116         /* remove our generic driver */
 117         usb_deregister(&generic_driver);
 118         usb_serial_deregister(&usb_serial_generic_device);
 119 #endif
 120 }
 121
 122 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 123 {
 124         int result = 0;
 125         unsigned long flags;
 126
 127         dbg("%s - port %d", __func__, port->number);
 128
 129         /* clear the throttle flags */
 130         spin_lock_irqsave(&port->lock, flags);
 131         port->throttled = 0;
 132         port->throttle_req = 0;
 133         spin_unlock_irqrestore(&port->lock, flags);
 134
 135         /* if we have a bulk endpoint, start reading from it */
 136         if (port->bulk_in_size)
 137                 result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
 138
 139         return result;
 140 }
 141 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 142
 143 static void generic_cleanup(struct usb_serial_port *port)
 144 {
 145         struct usb_serial *serial = port->serial;
 146         unsigned long flags;
 147         int i;
 148
 149         dbg("%s - port %d", __func__, port->number);
 150
 151         if (serial->dev) {
 152                 /* shutdown any bulk transfers that might be going on */
 153                 if (port->bulk_out_size) {
 154                         usb_kill_urb(port->write_urb);
 155                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 156                                 usb_kill_urb(port->write_urbs[i]);
 157
 158                         spin_lock_irqsave(&port->lock, flags);
 159                         kfifo_reset_out(&port->write_fifo);
 160                         spin_unlock_irqrestore(&port->lock, flags);
 161                 }
 162                 if (port->bulk_in_size)
 163                         usb_kill_urb(port->read_urb);
 164         }
 165 }
 166
 167 void usb_serial_generic_close(struct usb_serial_port *port)
 168 {
 169         dbg("%s - port %d", __func__, port->number);
 170         generic_cleanup(port);
 171 }
 172 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 173
 174 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 175                 void **dest, size_t size, const void *src, size_t count)
 176 {
 177         if (!*dest) {
 178                 size = count;
 179                 *dest = kmalloc(count, GFP_ATOMIC);
 180                 if (!*dest) {
 181                         dev_err(&port->dev, "%s - could not allocate buffer\n",
 182                                         __func__);
 183                         return -ENOMEM;
 184                 }
 185         }
 186         if (src) {
 187                 count = size;
 188                 memcpy(*dest, src, size);
 189         } else {
 190                 count = kfifo_out_locked(&port->write_fifo, *dest, size,
 191                                                                 &port->lock);
 192         }
 193         return count;
 194 }
 195 EXPORT_SYMBOL_GPL(usb_serial_generic_prepare_write_buffer);
 196
 197 static int usb_serial_multi_urb_write(struct tty_struct *tty,
 198         struct usb_serial_port *port, const unsigned char *buf, int count)
 199 {
 200         unsigned long flags;
 201         struct urb *urb;
 202         void *buffer;
 203         int status;
 204
 205         spin_lock_irqsave(&port->lock, flags);
 206         if (port->tx_urbs == MAX_TX_URBS) {
 207                 spin_unlock_irqrestore(&port->lock, flags);
 208                 dbg("%s - write limit hit", __func__);
 209                 return 0;
 210         }
 211         port->tx_urbs++;
 212         spin_unlock_irqrestore(&port->lock, flags);
 213
 214         urb = usb_alloc_urb(0, GFP_ATOMIC);
 215         if (!urb) {
 216                 dev_err(&port->dev, "%s - no free urbs available\n", __func__);
 217                 status = -ENOMEM;
 218                 goto err_urb;
 219         }
 220
 221         buffer = NULL;
 222         count = min_t(int, count, PAGE_SIZE);
 223         count = port->serial->type->prepare_write_buffer(port, &buffer, 0,
 224                                                                 buf, count);
 225         if (count < 0) {
 226                 status = count;
 227                 goto err_buf;
 228         }
 229         usb_serial_debug_data(debug, &port->dev, __func__, count, buffer);
 230         usb_fill_bulk_urb(urb, port->serial->dev,
 231                         usb_sndbulkpipe(port->serial->dev,
 232                                         port->bulk_out_endpointAddress),
 233                         buffer, count,
 234                         port->serial->type->write_bulk_callback, port);
 235
 236         status = usb_submit_urb(urb, GFP_ATOMIC);
 237         if (status) {
 238                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
 239                                 __func__, status);
 240                 goto err;
 241         }
 242         spin_lock_irqsave(&port->lock, flags);
 243         port->tx_bytes += urb->transfer_buffer_length;
 244         spin_unlock_irqrestore(&port->lock, flags);
 245
 246         usb_free_urb(urb);
 247
 248         return count;
 249 err:
 250         kfree(buffer);
 251 err_buf:
 252         usb_free_urb(urb);
 253 err_urb:
 254         spin_lock_irqsave(&port->lock, flags);
 255         port->tx_urbs--;
 256         spin_unlock_irqrestore(&port->lock, flags);
 257
 258         return status;
 259 }
 260
 261 /**
 262  * usb_serial_generic_write_start - kick off an URB write
 263  * @port:       Pointer to the &struct usb_serial_port data
 264  *
 265  * Returns zero on success, or a negative errno value
 266  */
 267 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 268 {
 269         struct urb *urb;
 270         int count, result;
 271         unsigned long flags;
 272         int i;
 273
 274         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 275                 return 0;
 276 retry:
 277         spin_lock_irqsave(&port->lock, flags);
 278         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 279                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 280                 spin_unlock_irqrestore(&port->lock, flags);
 281                 return 0;
 282         }
 283         i = (int)find_first_bit(&port->write_urbs_free,
 284                                                 ARRAY_SIZE(port->write_urbs));
 285         spin_unlock_irqrestore(&port->lock, flags);
 286
 287         urb = port->write_urbs[i];
 288         count = port->serial->type->prepare_write_buffer(port,
 289                                                 &urb->transfer_buffer,
 290                                                 port->bulk_out_size, NULL, 0);
 291         urb->transfer_buffer_length = count;
 292         usb_serial_debug_data(debug, &port->dev, __func__, count,
 293                                                 urb->transfer_buffer);
 294         result = usb_submit_urb(urb, GFP_ATOMIC);
 295         if (result) {
 296                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
 297                                                 __func__, result);
 298                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 299                 return result;
 300         }
 301         clear_bit(i, &port->write_urbs_free);
 302
 303         spin_lock_irqsave(&port->lock, flags);
 304         port->tx_bytes += count;
 305         spin_unlock_irqrestore(&port->lock, flags);
 306
 307         /* Try sending off another urb, unless in irq context (in which case
 308          * there will be no free urb). */
 309         if (!in_irq())
 310                 goto retry;
 311
 312         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 313
 314         return 0;
 315 }
 316
 317 /**
 318  * usb_serial_generic_write - generic write function for serial USB devices
 319  * @tty:        Pointer to &struct tty_struct for the device
 320  * @port:       Pointer to the &usb_serial_port structure for the device
 321  * @buf:        Pointer to the data to write
 322  * @count:      Number of bytes to write
 323  *
 324  * Returns the number of characters actually written, which may be anything
 325  * from zero to @count. If an error occurs, it returns the negative errno
 326  * value.
 327  */
 328 int usb_serial_generic_write(struct tty_struct *tty,
 329         struct usb_serial_port *port, const unsigned char *buf, int count)
 330 {
 331         struct usb_serial *serial = port->serial;
 332         int result;
 333
 334         dbg("%s - port %d", __func__, port->number);
 335
 336         /* only do something if we have a bulk out endpoint */
 337         if (!port->bulk_out_size)
 338                 return -ENODEV;
 339
 340         if (!count)
 341                 return 0;
 342
 343         if (serial->type->multi_urb_write)
 344                 return usb_serial_multi_urb_write(tty, port, buf, count);
 345
 346         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 347         result = usb_serial_generic_write_start(port);
 348
 349         if (result >= 0)
 350                 result = count;
 351
 352         return result;
 353 }
 354 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 355
 356 int usb_serial_generic_write_room(struct tty_struct *tty)
 357 {
 358         struct usb_serial_port *port = tty->driver_data;
 359         struct usb_serial *serial = port->serial;
 360         unsigned long flags;
 361         int room;
 362
 363         dbg("%s - port %d", __func__, port->number);
 364
 365         if (!port->bulk_out_size)
 366                 return 0;
 367
 368         spin_lock_irqsave(&port->lock, flags);
 369         if (serial->type->multi_urb_write)
 370                 room = (MAX_TX_URBS - port->tx_urbs) * PAGE_SIZE;
 371         else
 372                 room = kfifo_avail(&port->write_fifo);
 373         spin_unlock_irqrestore(&port->lock, flags);
 374
 375         dbg("%s - returns %d", __func__, room);
 376         return room;
 377 }
 378
 379 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 380 {
 381         struct usb_serial_port *port = tty->driver_data;
 382         struct usb_serial *serial = port->serial;
 383         unsigned long flags;
 384         int chars;
 385
 386         dbg("%s - port %d", __func__, port->number);
 387
 388         if (!port->bulk_out_size)
 389                 return 0;
 390
 391         spin_lock_irqsave(&port->lock, flags);
 392         if (serial->type->multi_urb_write)
 393                 chars = port->tx_bytes;
 394         else
 395                 chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 396         spin_unlock_irqrestore(&port->lock, flags);
 397
 398         dbg("%s - returns %d", __func__, chars);
 399         return chars;
 400 }
 401
 402 int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 403                                         gfp_t mem_flags)
 404 {
 405         int result;
 406
 407         result = usb_submit_urb(port->read_urb, mem_flags);
 408         if (result && result != -EPERM) {
 409                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
 410                                                         __func__, result);
 411         }
 412         return result;
 413 }
 414 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
 415
 416 void usb_serial_generic_process_read_urb(struct urb *urb)
 417 {
 418         struct usb_serial_port *port = urb->context;
 419         struct tty_struct *tty;
 420         char *ch = (char *)urb->transfer_buffer;
 421         int i;
 422
 423         tty = tty_port_tty_get(&port->port);
 424         if (!tty)
 425                 return;
 426
 427         /* The per character mucking around with sysrq path it too slow for
 428            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 429            where the USB serial is not a console anyway */
 430         if (!port->port.console || !port->sysrq)
 431                 tty_insert_flip_string(tty, ch, urb->actual_length);
 432         else {
 433                 for (i = 0; i < urb->actual_length; i++, ch++) {
 434                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 435                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 436                 }
 437         }
 438         tty_flip_buffer_push(tty);
 439         tty_kref_put(tty);
 440 }
 441 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 442
 443 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 444 {
 445         struct usb_serial_port *port = urb->context;
 446         unsigned char *data = urb->transfer_buffer;
 447         int status = urb->status;
 448         unsigned long flags;
 449
 450         dbg("%s - port %d", __func__, port->number);
 451
 452         if (unlikely(status != 0)) {
 453                 dbg("%s - nonzero read bulk status received: %d",
 454                     __func__, status);
 455                 return;
 456         }
 457
 458         usb_serial_debug_data(debug, &port->dev, __func__,
 459                                                 urb->actual_length, data);
 460         port->serial->type->process_read_urb(urb);
 461
 462         /* Throttle the device if requested by tty */
 463         spin_lock_irqsave(&port->lock, flags);
 464         port->throttled = port->throttle_req;
 465         if (!port->throttled) {
 466                 spin_unlock_irqrestore(&port->lock, flags);
 467                 usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
 468         } else
 469                 spin_unlock_irqrestore(&port->lock, flags);
 470 }
 471 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 472
 473 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 474 {
 475         unsigned long flags;
 476         struct usb_serial_port *port = urb->context;
 477         int status = urb->status;
 478         int i;
 479
 480         dbg("%s - port %d", __func__, port->number);
 481
 482         if (port->serial->type->multi_urb_write) {
 483                 kfree(urb->transfer_buffer);
 484
 485                 spin_lock_irqsave(&port->lock, flags);
 486                 port->tx_bytes -= urb->transfer_buffer_length;
 487                 port->tx_urbs--;
 488                 spin_unlock_irqrestore(&port->lock, flags);
 489         } else {
 490                 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 491                         if (port->write_urbs[i] == urb)
 492                                 break;
 493
 494                 spin_lock_irqsave(&port->lock, flags);
 495                 port->tx_bytes -= urb->transfer_buffer_length;
 496                 set_bit(i, &port->write_urbs_free);
 497                 spin_unlock_irqrestore(&port->lock, flags);
 498
 499                 if (status) {
 500                         spin_lock_irqsave(&port->lock, flags);
 501                         kfifo_reset_out(&port->write_fifo);
 502                         spin_unlock_irqrestore(&port->lock, flags);
 503                 } else {
 504                         usb_serial_generic_write_start(port);
 505                 }
 506         }
 507
 508         if (status)
 509                 dbg("%s - non-zero urb status: %d", __func__, status);
 510
 511         usb_serial_port_softint(port);
 512 }
 513 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 514
 515 void usb_serial_generic_throttle(struct tty_struct *tty)
 516 {
 517         struct usb_serial_port *port = tty->driver_data;
 518         unsigned long flags;
 519
 520         dbg("%s - port %d", __func__, port->number);
 521
 522         /* Set the throttle request flag. It will be picked up
 523          * by usb_serial_generic_read_bulk_callback(). */
 524         spin_lock_irqsave(&port->lock, flags);
 525         port->throttle_req = 1;
 526         spin_unlock_irqrestore(&port->lock, flags);
 527 }
 528 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 529
 530 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 531 {
 532         struct usb_serial_port *port = tty->driver_data;
 533         int was_throttled;
 534
 535         dbg("%s - port %d", __func__, port->number);
 536
 537         /* Clear the throttle flags */
 538         spin_lock_irq(&port->lock);
 539         was_throttled = port->throttled;
 540         port->throttled = port->throttle_req = 0;
 541         spin_unlock_irq(&port->lock);
 542
 543         if (was_throttled)
 544                 usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
 545 }
 546 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 547
 548 #ifdef CONFIG_MAGIC_SYSRQ
 549 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 550                         struct usb_serial_port *port, unsigned int ch)
 551 {
 552         if (port->sysrq && port->port.console) {
 553                 if (ch && time_before(jiffies, port->sysrq)) {
 554                         handle_sysrq(ch, tty);
 555                         port->sysrq = 0;
 556                         return 1;
 557                 }
 558                 port->sysrq = 0;
 559         }
 560         return 0;
 561 }
 562 #else
 563 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 564                         struct usb_serial_port *port, unsigned int ch)
 565 {
 566         return 0;
 567 }
 568 #endif
 569 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 570
 571 int usb_serial_handle_break(struct usb_serial_port *port)
 572 {
 573         if (!port->sysrq) {
 574                 port->sysrq = jiffies + HZ*5;
 575                 return 1;
 576         }
 577         port->sysrq = 0;
 578         return 0;
 579 }
 580 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 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->read_urb) {
 593                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 594                         if (r < 0)
 595                                 c++;
 596                 }
 597
 598                 if (port->bulk_out_size) {
 599                         r = usb_serial_generic_write_start(port);
 600                         if (r < 0)
 601                                 c++;
 602                 }
 603         }
 604
 605         return c ? -EIO : 0;
 606 }
 607 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 608
 609 void usb_serial_generic_disconnect(struct usb_serial *serial)
 610 {
 611         int i;
 612
 613         dbg("%s", __func__);
 614
 615         /* stop reads and writes on all ports */
 616         for (i = 0; i < serial->num_ports; ++i)
 617                 generic_cleanup(serial->port[i]);
 618 }
 619
 620 void usb_serial_generic_release(struct usb_serial *serial)
 621 {
 622         dbg("%s", __func__);
 623 }