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/sysrq.h>
  16 #include <linux/tty.h>
  17 #include <linux/tty_flip.h>
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/usb.h>
  21 #include <linux/usb/serial.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/kfifo.h>
  24 #include <linux/serial.h>
  25
  26 static int debug;
  27
  28 #ifdef CONFIG_USB_SERIAL_GENERIC
  29
  30 static int generic_probe(struct usb_interface *interface,
  31                          const struct usb_device_id *id);
  32
  33 static __u16 vendor  = 0x05f9;
  34 static __u16 product = 0xffff;
  35
  36 module_param(vendor, ushort, 0);
  37 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  38
  39 module_param(product, ushort, 0);
  40 MODULE_PARM_DESC(product, "User specified USB idProduct");
  41
  42 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  43
  44 /* we want to look at all devices, as the vendor/product id can change
  45  * depending on the command line argument */
  46 static const struct usb_device_id generic_serial_ids[] = {
  47         {.driver_info = 42},
  48         {}
  49 };
  50
  51 static struct usb_driver generic_driver = {
  52         .name =         "usbserial_generic",
  53         .probe =        generic_probe,
  54         .disconnect =   usb_serial_disconnect,
  55         .id_table =     generic_serial_ids,
  56         .no_dynamic_id =        1,
  57 };
  58
  59 /* All of the device info needed for the Generic Serial Converter */
  60 struct usb_serial_driver usb_serial_generic_device = {
  61         .driver = {
  62                 .owner =        THIS_MODULE,
  63                 .name =         "generic",
  64         },
  65         .id_table =             generic_device_ids,
  66         .usb_driver =           &generic_driver,
  67         .num_ports =            1,
  68         .disconnect =           usb_serial_generic_disconnect,
  69         .release =              usb_serial_generic_release,
  70         .throttle =             usb_serial_generic_throttle,
  71         .unthrottle =           usb_serial_generic_unthrottle,
  72         .resume =               usb_serial_generic_resume,
  73 };
  74
  75 static int generic_probe(struct usb_interface *interface,
  76                                const struct usb_device_id *id)
  77 {
  78         const struct usb_device_id *id_pattern;
  79
  80         id_pattern = usb_match_id(interface, generic_device_ids);
  81         if (id_pattern != NULL)
  82                 return usb_serial_probe(interface, id);
  83         return -ENODEV;
  84 }
  85 #endif
  86
  87 int usb_serial_generic_register(int _debug)
  88 {
  89         int retval = 0;
  90
  91         debug = _debug;
  92 #ifdef CONFIG_USB_SERIAL_GENERIC
  93         generic_device_ids[0].idVendor = vendor;
  94         generic_device_ids[0].idProduct = product;
  95         generic_device_ids[0].match_flags =
  96                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  97
  98         /* register our generic driver with ourselves */
  99         retval = usb_serial_register(&usb_serial_generic_device);
 100         if (retval)
 101                 goto exit;
 102         retval = usb_register(&generic_driver);
 103         if (retval)
 104                 usb_serial_deregister(&usb_serial_generic_device);
 105 exit:
 106 #endif
 107         return retval;
 108 }
 109
 110 void usb_serial_generic_deregister(void)
 111 {
 112 #ifdef CONFIG_USB_SERIAL_GENERIC
 113         /* remove our generic driver */
 114         usb_deregister(&generic_driver);
 115         usb_serial_deregister(&usb_serial_generic_device);
 116 #endif
 117 }
 118
 119 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 120 {
 121         struct usb_serial *serial = port->serial;
 122         int result = 0;
 123         unsigned long flags;
 124
 125         dbg("%s - port %d", __func__, port->number);
 126
 127         /* clear the throttle flags */
 128         spin_lock_irqsave(&port->lock, flags);
 129         port->throttled = 0;
 130         port->throttle_req = 0;
 131         spin_unlock_irqrestore(&port->lock, flags);
 132
 133         /* if we have a bulk endpoint, start reading from it */
 134         if (port->bulk_in_size) {
 135                 /* Start reading from the device */
 136                 usb_fill_bulk_urb(port->read_urb, serial->dev,
 137                                    usb_rcvbulkpipe(serial->dev,
 138                                                 port->bulk_in_endpointAddress),
 139                                    port->read_urb->transfer_buffer,
 140                                    port->read_urb->transfer_buffer_length,
 141                                    ((serial->type->read_bulk_callback) ?
 142                                      serial->type->read_bulk_callback :
 143                                      usb_serial_generic_read_bulk_callback),
 144                                    port);
 145                 result = usb_submit_urb(port->read_urb, GFP_KERNEL);
 146                 if (result)
 147                         dev_err(&port->dev,
 148                             "%s - failed resubmitting read urb, error %d\n",
 149                                                         __func__, result);
 150         }
 151
 152         return result;
 153 }
 154 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 155
 156 static void generic_cleanup(struct usb_serial_port *port)
 157 {
 158         struct usb_serial *serial = port->serial;
 159
 160         dbg("%s - port %d", __func__, port->number);
 161
 162         if (serial->dev) {
 163                 /* shutdown any bulk transfers that might be going on */
 164                 if (port->bulk_out_size)
 165                         usb_kill_urb(port->write_urb);
 166                 if (port->bulk_in_size)
 167                         usb_kill_urb(port->read_urb);
 168         }
 169 }
 170
 171 void usb_serial_generic_close(struct usb_serial_port *port)
 172 {
 173         dbg("%s - port %d", __func__, port->number);
 174         generic_cleanup(port);
 175 }
 176
 177 static int usb_serial_multi_urb_write(struct tty_struct *tty,
 178         struct usb_serial_port *port, const unsigned char *buf, int count)
 179 {
 180         unsigned long flags;
 181         struct urb *urb;
 182         unsigned char *buffer;
 183         int status;
 184         int towrite;
 185         int bwrite = 0;
 186
 187         dbg("%s - port %d", __func__, port->number);
 188
 189         if (count == 0)
 190                 dbg("%s - write request of 0 bytes", __func__);
 191
 192         while (count > 0) {
 193                 towrite = (count > port->bulk_out_size) ?
 194                         port->bulk_out_size : count;
 195                 spin_lock_irqsave(&port->lock, flags);
 196                 if (port->urbs_in_flight >
 197                     port->serial->type->max_in_flight_urbs) {
 198                         spin_unlock_irqrestore(&port->lock, flags);
 199                         dbg("%s - write limit hit", __func__);
 200                         return bwrite;
 201                 }
 202                 port->tx_bytes_flight += towrite;
 203                 port->urbs_in_flight++;
 204                 spin_unlock_irqrestore(&port->lock, flags);
 205
 206                 buffer = kmalloc(towrite, GFP_ATOMIC);
 207                 if (!buffer) {
 208                         dev_err(&port->dev,
 209                         "%s ran out of kernel memory for urb ...\n", __func__);
 210                         goto error_no_buffer;
 211                 }
 212
 213                 urb = usb_alloc_urb(0, GFP_ATOMIC);
 214                 if (!urb) {
 215                         dev_err(&port->dev, "%s - no more free urbs\n",
 216                                 __func__);
 217                         goto error_no_urb;
 218                 }
 219
 220                 /* Copy data */
 221                 memcpy(buffer, buf + bwrite, towrite);
 222                 usb_serial_debug_data(debug, &port->dev, __func__,
 223                                       towrite, buffer);
 224                 /* fill the buffer and send it */
 225                 usb_fill_bulk_urb(urb, port->serial->dev,
 226                         usb_sndbulkpipe(port->serial->dev,
 227                                         port->bulk_out_endpointAddress),
 228                         buffer, towrite,
 229                         usb_serial_generic_write_bulk_callback, port);
 230
 231                 status = usb_submit_urb(urb, GFP_ATOMIC);
 232                 if (status) {
 233                         dev_err(&port->dev,
 234                                 "%s - failed submitting write urb, error %d\n",
 235                                 __func__, status);
 236                         goto error;
 237                 }
 238
 239                 /* This urb is the responsibility of the host driver now */
 240                 usb_free_urb(urb);
 241                 dbg("%s write: %d", __func__, towrite);
 242                 count -= towrite;
 243                 bwrite += towrite;
 244         }
 245         return bwrite;
 246
 247 error:
 248         usb_free_urb(urb);
 249 error_no_urb:
 250         kfree(buffer);
 251 error_no_buffer:
 252         spin_lock_irqsave(&port->lock, flags);
 253         port->urbs_in_flight--;
 254         port->tx_bytes_flight -= towrite;
 255         spin_unlock_irqrestore(&port->lock, flags);
 256         return bwrite;
 257 }
 258
 259 /**
 260  * usb_serial_generic_write_start - kick off an URB write
 261  * @port:       Pointer to the &struct usb_serial_port data
 262  *
 263  * Returns the number of bytes queued on success. This will be zero if there
 264  * was nothing to send. Otherwise, it returns a negative errno value
 265  */
 266 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 267 {
 268         struct usb_serial *serial = port->serial;
 269         unsigned char *data;
 270         int result;
 271         int count;
 272         unsigned long flags;
 273         bool start_io;
 274
 275         /* Atomically determine whether we can and need to start a USB
 276          * operation. */
 277         spin_lock_irqsave(&port->lock, flags);
 278         if (port->write_urb_busy)
 279                 start_io = false;
 280         else {
 281                 start_io = (kfifo_len(&port->write_fifo) != 0);
 282                 port->write_urb_busy = start_io;
 283         }
 284         spin_unlock_irqrestore(&port->lock, flags);
 285
 286         if (!start_io)
 287                 return 0;
 288
 289         data = port->write_urb->transfer_buffer;
 290         count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
 291         usb_serial_debug_data(debug, &port->dev, __func__, count, data);
 292
 293         /* set up our urb */
 294         usb_fill_bulk_urb(port->write_urb, serial->dev,
 295                            usb_sndbulkpipe(serial->dev,
 296                                 port->bulk_out_endpointAddress),
 297                            port->write_urb->transfer_buffer, count,
 298                            ((serial->type->write_bulk_callback) ?
 299                              serial->type->write_bulk_callback :
 300                              usb_serial_generic_write_bulk_callback),
 301                            port);
 302
 303         /* send the data out the bulk port */
 304         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 305         if (result) {
 306                 dev_err(&port->dev,
 307                         "%s - failed submitting write urb, error %d\n",
 308                                                 __func__, result);
 309                 /* don't have to grab the lock here, as we will
 310                    retry if != 0 */
 311                 port->write_urb_busy = 0;
 312         } else
 313                 result = count;
 314
 315         return result;
 316 }
 317
 318 /**
 319  * usb_serial_generic_write - generic write function for serial USB devices
 320  * @tty:        Pointer to &struct tty_struct for the device
 321  * @port:       Pointer to the &usb_serial_port structure for the device
 322  * @buf:        Pointer to the data to write
 323  * @count:      Number of bytes to write
 324  *
 325  * Returns the number of characters actually written, which may be anything
 326  * from zero to @count. If an error occurs, it returns the negative errno
 327  * value.
 328  */
 329 int usb_serial_generic_write(struct tty_struct *tty,
 330         struct usb_serial_port *port, const unsigned char *buf, int count)
 331 {
 332         struct usb_serial *serial = port->serial;
 333         int result;
 334
 335         dbg("%s - port %d", __func__, port->number);
 336
 337         /* only do something if we have a bulk out endpoint */
 338         if (!port->bulk_out_size)
 339                 return -ENODEV;
 340
 341         if (count == 0) {
 342                 dbg("%s - write request of 0 bytes", __func__);
 343                 return 0;
 344         }
 345
 346         if (serial->type->max_in_flight_urbs)
 347                 return usb_serial_multi_urb_write(tty, port,
 348                                                   buf, count);
 349
 350         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 351         result = usb_serial_generic_write_start(port);
 352
 353         if (result >= 0)
 354                 result = count;
 355
 356         return result;
 357 }
 358 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 359
 360 int usb_serial_generic_write_room(struct tty_struct *tty)
 361 {
 362         struct usb_serial_port *port = tty->driver_data;
 363         struct usb_serial *serial = port->serial;
 364         unsigned long flags;
 365         int room = 0;
 366
 367         dbg("%s - port %d", __func__, port->number);
 368
 369         if (!port->bulk_out_size)
 370                 return 0;
 371
 372         spin_lock_irqsave(&port->lock, flags);
 373         if (serial->type->max_in_flight_urbs) {
 374                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
 375                         room = port->bulk_out_size *
 376                                 (serial->type->max_in_flight_urbs -
 377                                  port->urbs_in_flight);
 378         } else {
 379                 room = kfifo_avail(&port->write_fifo);
 380         }
 381         spin_unlock_irqrestore(&port->lock, flags);
 382
 383         dbg("%s - returns %d", __func__, room);
 384         return room;
 385 }
 386
 387 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 388 {
 389         struct usb_serial_port *port = tty->driver_data;
 390         struct usb_serial *serial = port->serial;
 391         unsigned long flags;
 392         int chars;
 393
 394         dbg("%s - port %d", __func__, port->number);
 395
 396         if (!port->bulk_out_size)
 397                 return 0;
 398
 399         spin_lock_irqsave(&port->lock, flags);
 400         if (serial->type->max_in_flight_urbs)
 401                 chars = port->tx_bytes_flight;
 402         else
 403                 chars = kfifo_len(&port->write_fifo);
 404         spin_unlock_irqrestore(&port->lock, flags);
 405
 406         dbg("%s - returns %d", __func__, chars);
 407         return chars;
 408 }
 409
 410
 411 void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
 412                         gfp_t mem_flags)
 413 {
 414         struct urb *urb = port->read_urb;
 415         struct usb_serial *serial = port->serial;
 416         int result;
 417
 418         /* Continue reading from device */
 419         usb_fill_bulk_urb(urb, serial->dev,
 420                            usb_rcvbulkpipe(serial->dev,
 421                                         port->bulk_in_endpointAddress),
 422                            urb->transfer_buffer,
 423                            urb->transfer_buffer_length,
 424                            ((serial->type->read_bulk_callback) ?
 425                              serial->type->read_bulk_callback :
 426                              usb_serial_generic_read_bulk_callback), port);
 427
 428         result = usb_submit_urb(urb, mem_flags);
 429         if (result && result != -EPERM) {
 430                 dev_err(&port->dev,
 431                         "%s - failed resubmitting read urb, error %d\n",
 432                                                         __func__, result);
 433         }
 434 }
 435 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
 436
 437 /* Push data to tty layer and resubmit the bulk read URB */
 438 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 439 {
 440         struct urb *urb = port->read_urb;
 441         struct tty_struct *tty = tty_port_tty_get(&port->port);
 442         char *ch = (char *)urb->transfer_buffer;
 443         int i;
 444
 445         if (!tty)
 446                 goto done;
 447
 448         /* The per character mucking around with sysrq path it too slow for
 449            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 450            where the USB serial is not a console anyway */
 451         if (!port->port.console || !port->sysrq)
 452                 tty_insert_flip_string(tty, ch, urb->actual_length);
 453         else {
 454                 /* Push data to tty */
 455                 for (i = 0; i < urb->actual_length; i++, ch++) {
 456                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 457                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 458                 }
 459         }
 460         tty_flip_buffer_push(tty);
 461         tty_kref_put(tty);
 462 done:
 463         usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
 464 }
 465
 466 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 467 {
 468         struct usb_serial_port *port = urb->context;
 469         unsigned char *data = urb->transfer_buffer;
 470         int status = urb->status;
 471         unsigned long flags;
 472
 473         dbg("%s - port %d", __func__, port->number);
 474
 475         if (unlikely(status != 0)) {
 476                 dbg("%s - nonzero read bulk status received: %d",
 477                     __func__, status);
 478                 return;
 479         }
 480
 481         usb_serial_debug_data(debug, &port->dev, __func__,
 482                                                 urb->actual_length, data);
 483
 484         /* Throttle the device if requested by tty */
 485         spin_lock_irqsave(&port->lock, flags);
 486         port->throttled = port->throttle_req;
 487         if (!port->throttled) {
 488                 spin_unlock_irqrestore(&port->lock, flags);
 489                 flush_and_resubmit_read_urb(port);
 490         } else
 491                 spin_unlock_irqrestore(&port->lock, flags);
 492 }
 493 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 494
 495 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 496 {
 497         unsigned long flags;
 498         struct usb_serial_port *port = urb->context;
 499         int status = urb->status;
 500
 501         dbg("%s - port %d", __func__, port->number);
 502
 503         if (port->serial->type->max_in_flight_urbs) {
 504                 kfree(urb->transfer_buffer);
 505
 506                 spin_lock_irqsave(&port->lock, flags);
 507                 --port->urbs_in_flight;
 508                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 509                 if (port->urbs_in_flight < 0)
 510                         port->urbs_in_flight = 0;
 511                 spin_unlock_irqrestore(&port->lock, flags);
 512         } else {
 513                 port->write_urb_busy = 0;
 514
 515                 if (status)
 516                         kfifo_reset_out(&port->write_fifo);
 517                 else
 518                         usb_serial_generic_write_start(port);
 519         }
 520
 521         if (status)
 522                 dbg("%s - non-zero urb status: %d", __func__, status);
 523
 524         usb_serial_port_softint(port);
 525 }
 526 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 527
 528 void usb_serial_generic_throttle(struct tty_struct *tty)
 529 {
 530         struct usb_serial_port *port = tty->driver_data;
 531         unsigned long flags;
 532
 533         dbg("%s - port %d", __func__, port->number);
 534
 535         /* Set the throttle request flag. It will be picked up
 536          * by usb_serial_generic_read_bulk_callback(). */
 537         spin_lock_irqsave(&port->lock, flags);
 538         port->throttle_req = 1;
 539         spin_unlock_irqrestore(&port->lock, flags);
 540 }
 541
 542 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 543 {
 544         struct usb_serial_port *port = tty->driver_data;
 545         int was_throttled;
 546         unsigned long flags;
 547
 548         dbg("%s - port %d", __func__, port->number);
 549
 550         /* Clear the throttle flags */
 551         spin_lock_irqsave(&port->lock, flags);
 552         was_throttled = port->throttled;
 553         port->throttled = port->throttle_req = 0;
 554         spin_unlock_irqrestore(&port->lock, flags);
 555
 556         if (was_throttled) {
 557                 /* Resume reading from device */
 558                 flush_and_resubmit_read_urb(port);
 559         }
 560 }
 561
 562 #ifdef CONFIG_MAGIC_SYSRQ
 563 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 564                         struct usb_serial_port *port, unsigned int ch)
 565 {
 566         if (port->sysrq && port->port.console) {
 567                 if (ch && time_before(jiffies, port->sysrq)) {
 568                         handle_sysrq(ch, tty);
 569                         port->sysrq = 0;
 570                         return 1;
 571                 }
 572                 port->sysrq = 0;
 573         }
 574         return 0;
 575 }
 576 #else
 577 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 578                         struct usb_serial_port *port, unsigned int ch)
 579 {
 580         return 0;
 581 }
 582 #endif
 583 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 584
 585 int usb_serial_handle_break(struct usb_serial_port *port)
 586 {
 587         if (!port->sysrq) {
 588                 port->sysrq = jiffies + HZ*5;
 589                 return 1;
 590         }
 591         port->sysrq = 0;
 592         return 0;
 593 }
 594 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 595
 596 int usb_serial_generic_resume(struct usb_serial *serial)
 597 {
 598         struct usb_serial_port *port;
 599         int i, c = 0, r;
 600
 601         for (i = 0; i < serial->num_ports; i++) {
 602                 port = serial->port[i];
 603                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 604                         continue;
 605
 606                 if (port->read_urb) {
 607                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 608                         if (r < 0)
 609                                 c++;
 610                 }
 611
 612                 if (port->write_urb) {
 613                         r = usb_serial_generic_write_start(port);
 614                         if (r < 0)
 615                                 c++;
 616                 }
 617         }
 618
 619         return c ? -EIO : 0;
 620 }
 621 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 622
 623 void usb_serial_generic_disconnect(struct usb_serial *serial)
 624 {
 625         int i;
 626
 627         dbg("%s", __func__);
 628
 629         /* stop reads and writes on all ports */
 630         for (i = 0; i < serial->num_ports; ++i)
 631                 generic_cleanup(serial->port[i]);
 632 }
 633
 634 void usb_serial_generic_release(struct usb_serial *serial)
 635 {
 636         dbg("%s", __func__);
 637 }