drivers/usb/serial/generic.c

   1 /*
   2  * USB Serial Converter Generic functions
   3  *
   4  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License version
   8  *      2 as published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/errno.h>
  14 #include <linux/slab.h>
  15 #include <linux/tty.h>
  16 #include <linux/tty_flip.h>
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/usb.h>
  20 #include <linux/usb/serial.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/kfifo.h>
  23
  24 static int debug;
  25
  26 #ifdef CONFIG_USB_SERIAL_GENERIC
  27
  28 static int generic_probe(struct usb_interface *interface,
  29                          const struct usb_device_id *id);
  30
  31 static __u16 vendor  = 0x05f9;
  32 static __u16 product = 0xffff;
  33
  34 module_param(vendor, ushort, 0);
  35 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  36
  37 module_param(product, ushort, 0);
  38 MODULE_PARM_DESC(product, "User specified USB idProduct");
  39
  40 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  41
  42 /* we want to look at all devices, as the vendor/product id can change
  43  * depending on the command line argument */
  44 static struct usb_device_id generic_serial_ids[] = {
  45         {.driver_info = 42},
  46         {}
  47 };
  48
  49 static struct usb_driver generic_driver = {
  50         .name =         "usbserial_generic",
  51         .probe =        generic_probe,
  52         .disconnect =   usb_serial_disconnect,
  53         .id_table =     generic_serial_ids,
  54         .no_dynamic_id =        1,
  55 };
  56
  57 /* All of the device info needed for the Generic Serial Converter */
  58 struct usb_serial_driver usb_serial_generic_device = {
  59         .driver = {
  60                 .owner =        THIS_MODULE,
  61                 .name =         "generic",
  62         },
  63         .id_table =             generic_device_ids,
  64         .usb_driver =           &generic_driver,
  65         .num_ports =            1,
  66         .disconnect =           usb_serial_generic_disconnect,
  67         .release =              usb_serial_generic_release,
  68         .throttle =             usb_serial_generic_throttle,
  69         .unthrottle =           usb_serial_generic_unthrottle,
  70         .resume =               usb_serial_generic_resume,
  71 };
  72
  73 static int generic_probe(struct usb_interface *interface,
  74                                const struct usb_device_id *id)
  75 {
  76         const struct usb_device_id *id_pattern;
  77
  78         id_pattern = usb_match_id(interface, generic_device_ids);
  79         if (id_pattern != NULL)
  80                 return usb_serial_probe(interface, id);
  81         return -ENODEV;
  82 }
  83 #endif
  84
  85 int usb_serial_generic_register(int _debug)
  86 {
  87         int retval = 0;
  88
  89         debug = _debug;
  90 #ifdef CONFIG_USB_SERIAL_GENERIC
  91         generic_device_ids[0].idVendor = vendor;
  92         generic_device_ids[0].idProduct = product;
  93         generic_device_ids[0].match_flags =
  94                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  95
  96         /* register our generic driver with ourselves */
  97         retval = usb_serial_register(&usb_serial_generic_device);
  98         if (retval)
  99                 goto exit;
 100         retval = usb_register(&generic_driver);
 101         if (retval)
 102                 usb_serial_deregister(&usb_serial_generic_device);
 103 exit:
 104 #endif
 105         return retval;
 106 }
 107
 108 void usb_serial_generic_deregister(void)
 109 {
 110 #ifdef CONFIG_USB_SERIAL_GENERIC
 111         /* remove our generic driver */
 112         usb_deregister(&generic_driver);
 113         usb_serial_deregister(&usb_serial_generic_device);
 114 #endif
 115 }
 116
 117 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 118 {
 119         struct usb_serial *serial = port->serial;
 120         int result = 0;
 121         unsigned long flags;
 122
 123         dbg("%s - port %d", __func__, port->number);
 124
 125         /* clear the throttle flags */
 126         spin_lock_irqsave(&port->lock, flags);
 127         port->throttled = 0;
 128         port->throttle_req = 0;
 129         spin_unlock_irqrestore(&port->lock, flags);
 130
 131         /* if we have a bulk endpoint, start reading from it */
 132         if (serial->num_bulk_in) {
 133                 /* Start reading from the device */
 134                 usb_fill_bulk_urb(port->read_urb, serial->dev,
 135                                    usb_rcvbulkpipe(serial->dev,
 136                                                 port->bulk_in_endpointAddress),
 137                                    port->read_urb->transfer_buffer,
 138                                    port->read_urb->transfer_buffer_length,
 139                                    ((serial->type->read_bulk_callback) ?
 140                                      serial->type->read_bulk_callback :
 141                                      usb_serial_generic_read_bulk_callback),
 142                                    port);
 143                 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
 144                 if (result)
 145                         dev_err(&port->dev,
 146                             "%s - failed resubmitting read urb, error %d\n",
 147                                                         __func__, result);
 148         }
 149
 150         return result;
 151 }
 152 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 153
 154 static void generic_cleanup(struct usb_serial_port *port)
 155 {
 156         struct usb_serial *serial = port->serial;
 157
 158         dbg("%s - port %d", __func__, port->number);
 159
 160         if (serial->dev) {
 161                 /* shutdown any bulk reads that might be going on */
 162                 if (serial->num_bulk_out)
 163                         usb_kill_urb(port->write_urb);
 164                 if (serial->num_bulk_in)
 165                         usb_kill_urb(port->read_urb);
 166         }
 167 }
 168
 169 void usb_serial_generic_close(struct usb_serial_port *port)
 170 {
 171         dbg("%s - port %d", __func__, port->number);
 172         generic_cleanup(port);
 173 }
 174
 175 static int usb_serial_multi_urb_write(struct tty_struct *tty,
 176         struct usb_serial_port *port, const unsigned char *buf, int count)
 177 {
 178         unsigned long flags;
 179         struct urb *urb;
 180         unsigned char *buffer;
 181         int status;
 182         int towrite;
 183         int bwrite = 0;
 184
 185         dbg("%s - port %d", __func__, port->number);
 186
 187         if (count == 0)
 188                 dbg("%s - write request of 0 bytes", __func__);
 189
 190         while (count > 0) {
 191                 towrite = (count > port->bulk_out_size) ?
 192                         port->bulk_out_size : count;
 193                 spin_lock_irqsave(&port->lock, flags);
 194                 if (port->urbs_in_flight >
 195                     port->serial->type->max_in_flight_urbs) {
 196                         spin_unlock_irqrestore(&port->lock, flags);
 197                         dbg("%s - write limit hit\n", __func__);
 198                         return bwrite;
 199                 }
 200                 port->tx_bytes_flight += towrite;
 201                 port->urbs_in_flight++;
 202                 spin_unlock_irqrestore(&port->lock, flags);
 203
 204                 buffer = kmalloc(towrite, GFP_ATOMIC);
 205                 if (!buffer) {
 206                         dev_err(&port->dev,
 207                         "%s ran out of kernel memory for urb ...\n", __func__);
 208                         goto error_no_buffer;
 209                 }
 210
 211                 urb = usb_alloc_urb(0, GFP_ATOMIC);
 212                 if (!urb) {
 213                         dev_err(&port->dev, "%s - no more free urbs\n",
 214                                 __func__);
 215                         goto error_no_urb;
 216                 }
 217
 218                 /* Copy data */
 219                 memcpy(buffer, buf + bwrite, towrite);
 220                 usb_serial_debug_data(debug, &port->dev, __func__,
 221                                       towrite, buffer);
 222                 /* fill the buffer and send it */
 223                 usb_fill_bulk_urb(urb, port->serial->dev,
 224                         usb_sndbulkpipe(port->serial->dev,
 225                                         port->bulk_out_endpointAddress),
 226                         buffer, towrite,
 227                         usb_serial_generic_write_bulk_callback, port);
 228
 229                 status = usb_submit_urb(urb, GFP_ATOMIC);
 230                 if (status) {
 231                         dev_err(&port->dev,
 232                                 "%s - failed submitting write urb, error %d\n",
 233                                 __func__, status);
 234                         goto error;
 235                 }
 236
 237                 /* This urb is the responsibility of the host driver now */
 238                 usb_free_urb(urb);
 239                 dbg("%s write: %d", __func__, towrite);
 240                 count -= towrite;
 241                 bwrite += towrite;
 242         }
 243         return bwrite;
 244
 245 error:
 246         usb_free_urb(urb);
 247 error_no_urb:
 248         kfree(buffer);
 249 error_no_buffer:
 250         spin_lock_irqsave(&port->lock, flags);
 251         port->urbs_in_flight--;
 252         port->tx_bytes_flight -= towrite;
 253         spin_unlock_irqrestore(&port->lock, flags);
 254         return bwrite;
 255 }
 256
 257 /**
 258  * usb_serial_generic_write_start - kick off an URB write
 259  * @port:       Pointer to the &struct usb_serial_port data
 260  *
 261  * Returns the number of bytes queued on success. This will be zero if there
 262  * was nothing to send. Otherwise, it returns a negative errno value
 263  */
 264 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 265 {
 266         struct usb_serial *serial = port->serial;
 267         unsigned char *data;
 268         int result;
 269         int count;
 270         unsigned long flags;
 271         bool start_io;
 272
 273         /* Atomically determine whether we can and need to start a USB
 274          * operation. */
 275         spin_lock_irqsave(&port->lock, flags);
 276         if (port->write_urb_busy)
 277                 start_io = false;
 278         else {
 279                 start_io = (kfifo_len(&port->write_fifo) != 0);
 280                 port->write_urb_busy = start_io;
 281         }
 282         spin_unlock_irqrestore(&port->lock, flags);
 283
 284         if (!start_io)
 285                 return 0;
 286
 287         data = port->write_urb->transfer_buffer;
 288         count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
 289         usb_serial_debug_data(debug, &port->dev, __func__, count, data);
 290
 291         /* set up our urb */
 292         usb_fill_bulk_urb(port->write_urb, serial->dev,
 293                            usb_sndbulkpipe(serial->dev,
 294                                 port->bulk_out_endpointAddress),
 295                            port->write_urb->transfer_buffer, count,
 296                            ((serial->type->write_bulk_callback) ?
 297                              serial->type->write_bulk_callback :
 298                              usb_serial_generic_write_bulk_callback),
 299                            port);
 300
 301         /* send the data out the bulk port */
 302         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 303         if (result) {
 304                 dev_err(&port->dev,
 305                         "%s - failed submitting write urb, error %d\n",
 306                                                 __func__, result);
 307                 /* don't have to grab the lock here, as we will
 308                    retry if != 0 */
 309                 port->write_urb_busy = 0;
 310         } else
 311                 result = count;
 312
 313         return result;
 314 }
 315
 316 /**
 317  * usb_serial_generic_write - generic write function for serial USB devices
 318  * @tty:        Pointer to &struct tty_struct for the device
 319  * @port:       Pointer to the &usb_serial_port structure for the device
 320  * @buf:        Pointer to the data to write
 321  * @count:      Number of bytes to write
 322  *
 323  * Returns the number of characters actually written, which may be anything
 324  * from zero to @count. If an error occurs, it returns the negative errno
 325  * value.
 326  */
 327 int usb_serial_generic_write(struct tty_struct *tty,
 328         struct usb_serial_port *port, const unsigned char *buf, int count)
 329 {
 330         struct usb_serial *serial = port->serial;
 331         int result;
 332
 333         dbg("%s - port %d", __func__, port->number);
 334
 335         if (count == 0) {
 336                 dbg("%s - write request of 0 bytes", __func__);
 337                 return 0;
 338         }
 339
 340         /* only do something if we have a bulk out endpoint */
 341         if (!serial->num_bulk_out)
 342                 return 0;
 343
 344         if (serial->type->max_in_flight_urbs)
 345                 return usb_serial_multi_urb_write(tty, port,
 346                                                   buf, count);
 347
 348         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 349         result = usb_serial_generic_write_start(port);
 350
 351         if (result >= 0)
 352                 result = count;
 353
 354         return result;
 355 }
 356 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 357
 358 int usb_serial_generic_write_room(struct tty_struct *tty)
 359 {
 360         struct usb_serial_port *port = tty->driver_data;
 361         struct usb_serial *serial = port->serial;
 362         unsigned long flags;
 363         int room = 0;
 364
 365         dbg("%s - port %d", __func__, port->number);
 366         spin_lock_irqsave(&port->lock, flags);
 367         if (serial->type->max_in_flight_urbs) {
 368                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
 369                         room = port->bulk_out_size *
 370                                 (serial->type->max_in_flight_urbs -
 371                                  port->urbs_in_flight);
 372         } else if (serial->num_bulk_out)
 373                 room = kfifo_avail(&port->write_fifo);
 374         spin_unlock_irqrestore(&port->lock, flags);
 375
 376         dbg("%s - returns %d", __func__, room);
 377         return room;
 378 }
 379
 380 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 381 {
 382         struct usb_serial_port *port = tty->driver_data;
 383         struct usb_serial *serial = port->serial;
 384         int chars = 0;
 385         unsigned long flags;
 386
 387         dbg("%s - port %d", __func__, port->number);
 388
 389         if (serial->type->max_in_flight_urbs) {
 390                 spin_lock_irqsave(&port->lock, flags);
 391                 chars = port->tx_bytes_flight;
 392                 spin_unlock_irqrestore(&port->lock, flags);
 393         } else if (serial->num_bulk_out)
 394                 chars = kfifo_len(&port->write_fifo);
 395
 396         dbg("%s - returns %d", __func__, chars);
 397         return chars;
 398 }
 399
 400
 401 void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
 402                         gfp_t mem_flags)
 403 {
 404         struct urb *urb = port->read_urb;
 405         struct usb_serial *serial = port->serial;
 406         int result;
 407
 408         /* Continue reading from device */
 409         usb_fill_bulk_urb(urb, serial->dev,
 410                            usb_rcvbulkpipe(serial->dev,
 411                                         port->bulk_in_endpointAddress),
 412                            urb->transfer_buffer,
 413                            urb->transfer_buffer_length,
 414                            ((serial->type->read_bulk_callback) ?
 415                              serial->type->read_bulk_callback :
 416                              usb_serial_generic_read_bulk_callback), port);
 417         result = usb_submit_urb(urb, mem_flags);
 418         if (result)
 419                 dev_err(&port->dev,
 420                         "%s - failed resubmitting read urb, error %d\n",
 421                                                         __func__, result);
 422 }
 423 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
 424
 425 /* Push data to tty layer and resubmit the bulk read URB */
 426 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 427 {
 428         struct urb *urb = port->read_urb;
 429         struct tty_struct *tty = tty_port_tty_get(&port->port);
 430         char *ch = (char *)urb->transfer_buffer;
 431         int i;
 432
 433         if (!tty)
 434                 goto done;
 435
 436         /* The per character mucking around with sysrq path it too slow for
 437            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 438            where the USB serial is not a console anyway */
 439         if (!port->console || !port->sysrq)
 440                 tty_insert_flip_string(tty, ch, urb->actual_length);
 441         else {
 442                 /* Push data to tty */
 443                 for (i = 0; i < urb->actual_length; i++, ch++) {
 444                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 445                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 446                 }
 447         }
 448         tty_flip_buffer_push(tty);
 449         tty_kref_put(tty);
 450 done:
 451         usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
 452 }
 453
 454 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 455 {
 456         struct usb_serial_port *port = urb->context;
 457         unsigned char *data = urb->transfer_buffer;
 458         int status = urb->status;
 459         unsigned long flags;
 460
 461         dbg("%s - port %d", __func__, port->number);
 462
 463         if (unlikely(status != 0)) {
 464                 dbg("%s - nonzero read bulk status received: %d",
 465                     __func__, status);
 466                 return;
 467         }
 468
 469         usb_serial_debug_data(debug, &port->dev, __func__,
 470                                                 urb->actual_length, data);
 471
 472         /* Throttle the device if requested by tty */
 473         spin_lock_irqsave(&port->lock, flags);
 474         port->throttled = port->throttle_req;
 475         if (!port->throttled) {
 476                 spin_unlock_irqrestore(&port->lock, flags);
 477                 flush_and_resubmit_read_urb(port);
 478         } else
 479                 spin_unlock_irqrestore(&port->lock, flags);
 480 }
 481 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 482
 483 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 484 {
 485         unsigned long flags;
 486         struct usb_serial_port *port = urb->context;
 487         int status = urb->status;
 488
 489         dbg("%s - port %d", __func__, port->number);
 490
 491         if (port->serial->type->max_in_flight_urbs) {
 492                 spin_lock_irqsave(&port->lock, flags);
 493                 --port->urbs_in_flight;
 494                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 495                 if (port->urbs_in_flight < 0)
 496                         port->urbs_in_flight = 0;
 497                 spin_unlock_irqrestore(&port->lock, flags);
 498
 499                 if (status) {
 500                         dbg("%s - nonzero multi-urb write bulk status "
 501                                 "received: %d", __func__, status);
 502                         return;
 503                 }
 504         } else {
 505                 port->write_urb_busy = 0;
 506
 507                 if (status) {
 508                         dbg("%s - nonzero multi-urb write bulk status "
 509                                 "received: %d", __func__, status);
 510                         kfifo_reset_out(&port->write_fifo);
 511                 } else
 512                         usb_serial_generic_write_start(port);
 513         }
 514
 515         usb_serial_port_softint(port);
 516 }
 517 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 518
 519 void usb_serial_generic_throttle(struct tty_struct *tty)
 520 {
 521         struct usb_serial_port *port = tty->driver_data;
 522         unsigned long flags;
 523
 524         dbg("%s - port %d", __func__, port->number);
 525
 526         /* Set the throttle request flag. It will be picked up
 527          * by usb_serial_generic_read_bulk_callback(). */
 528         spin_lock_irqsave(&port->lock, flags);
 529         port->throttle_req = 1;
 530         spin_unlock_irqrestore(&port->lock, flags);
 531 }
 532
 533 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 534 {
 535         struct usb_serial_port *port = tty->driver_data;
 536         int was_throttled;
 537         unsigned long flags;
 538
 539         dbg("%s - port %d", __func__, port->number);
 540
 541         /* Clear the throttle flags */
 542         spin_lock_irqsave(&port->lock, flags);
 543         was_throttled = port->throttled;
 544         port->throttled = port->throttle_req = 0;
 545         spin_unlock_irqrestore(&port->lock, flags);
 546
 547         if (was_throttled) {
 548                 /* Resume reading from device */
 549                 flush_and_resubmit_read_urb(port);
 550         }
 551 }
 552
 553 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 554                         struct usb_serial_port *port, unsigned int ch)
 555 {
 556         if (port->sysrq && port->console) {
 557                 if (ch && time_before(jiffies, port->sysrq)) {
 558                         handle_sysrq(ch, tty);
 559                         port->sysrq = 0;
 560                         return 1;
 561                 }
 562                 port->sysrq = 0;
 563         }
 564         return 0;
 565 }
 566 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 567
 568 int usb_serial_handle_break(struct usb_serial_port *port)
 569 {
 570         if (!port->sysrq) {
 571                 port->sysrq = jiffies + HZ*5;
 572                 return 1;
 573         }
 574         port->sysrq = 0;
 575         return 0;
 576 }
 577 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 578
 579 int usb_serial_generic_resume(struct usb_serial *serial)
 580 {
 581         struct usb_serial_port *port;
 582         int i, c = 0, r;
 583
 584         for (i = 0; i < serial->num_ports; i++) {
 585                 port = serial->port[i];
 586                 if (!port->port.count)
 587                         continue;
 588
 589                 if (port->read_urb) {
 590                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 591                         if (r < 0)
 592                                 c++;
 593                 }
 594
 595                 if (port->write_urb) {
 596                         r = usb_serial_generic_write_start(port);
 597                         if (r < 0)
 598                                 c++;
 599                 }
 600         }
 601
 602         return c ? -EIO : 0;
 603 }
 604 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 605
 606 void usb_serial_generic_disconnect(struct usb_serial *serial)
 607 {
 608         int i;
 609
 610         dbg("%s", __func__);
 611
 612         /* stop reads and writes on all ports */
 613         for (i = 0; i < serial->num_ports; ++i)
 614                 generic_cleanup(serial->port[i]);
 615 }
 616
 617 void usb_serial_generic_release(struct usb_serial *serial)
 618 {
 619         dbg("%s", __func__);
 620 }