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         int result = 0;
 122         unsigned long flags;
 123
 124         dbg("%s - port %d", __func__, port->number);
 125
 126         /* clear the throttle flags */
 127         spin_lock_irqsave(&port->lock, flags);
 128         port->throttled = 0;
 129         port->throttle_req = 0;
 130         spin_unlock_irqrestore(&port->lock, flags);
 131
 132         /* if we have a bulk endpoint, start reading from it */
 133         if (port->bulk_in_size)
 134                 result = usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
 135
 136         return result;
 137 }
 138 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 139
 140 static void generic_cleanup(struct usb_serial_port *port)
 141 {
 142         struct usb_serial *serial = port->serial;
 143         unsigned long flags;
 144
 145         dbg("%s - port %d", __func__, port->number);
 146
 147         if (serial->dev) {
 148                 /* shutdown any bulk transfers that might be going on */
 149                 if (port->bulk_out_size) {
 150                         usb_kill_urb(port->write_urb);
 151
 152                         spin_lock_irqsave(&port->lock, flags);
 153                         kfifo_reset_out(&port->write_fifo);
 154                         spin_unlock_irqrestore(&port->lock, flags);
 155                 }
 156                 if (port->bulk_in_size)
 157                         usb_kill_urb(port->read_urb);
 158         }
 159 }
 160
 161 void usb_serial_generic_close(struct usb_serial_port *port)
 162 {
 163         dbg("%s - port %d", __func__, port->number);
 164         generic_cleanup(port);
 165 }
 166 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 167
 168 static int usb_serial_multi_urb_write(struct tty_struct *tty,
 169         struct usb_serial_port *port, const unsigned char *buf, int count)
 170 {
 171         unsigned long flags;
 172         struct urb *urb;
 173         unsigned char *buffer;
 174         int status;
 175         int towrite;
 176         int bwrite = 0;
 177
 178         dbg("%s - port %d", __func__, port->number);
 179
 180         if (count == 0)
 181                 dbg("%s - write request of 0 bytes", __func__);
 182
 183         while (count > 0) {
 184                 towrite = (count > port->bulk_out_size) ?
 185                         port->bulk_out_size : count;
 186                 spin_lock_irqsave(&port->lock, flags);
 187                 if (port->urbs_in_flight >
 188                     port->serial->type->max_in_flight_urbs) {
 189                         spin_unlock_irqrestore(&port->lock, flags);
 190                         dbg("%s - write limit hit", __func__);
 191                         return bwrite;
 192                 }
 193                 port->tx_bytes_flight += towrite;
 194                 port->urbs_in_flight++;
 195                 spin_unlock_irqrestore(&port->lock, flags);
 196
 197                 buffer = kmalloc(towrite, GFP_ATOMIC);
 198                 if (!buffer) {
 199                         dev_err(&port->dev,
 200                         "%s ran out of kernel memory for urb ...\n", __func__);
 201                         goto error_no_buffer;
 202                 }
 203
 204                 urb = usb_alloc_urb(0, GFP_ATOMIC);
 205                 if (!urb) {
 206                         dev_err(&port->dev, "%s - no more free urbs\n",
 207                                 __func__);
 208                         goto error_no_urb;
 209                 }
 210
 211                 /* Copy data */
 212                 memcpy(buffer, buf + bwrite, towrite);
 213                 usb_serial_debug_data(debug, &port->dev, __func__,
 214                                       towrite, buffer);
 215                 /* fill the buffer and send it */
 216                 usb_fill_bulk_urb(urb, port->serial->dev,
 217                         usb_sndbulkpipe(port->serial->dev,
 218                                         port->bulk_out_endpointAddress),
 219                         buffer, towrite,
 220                         usb_serial_generic_write_bulk_callback, port);
 221
 222                 status = usb_submit_urb(urb, GFP_ATOMIC);
 223                 if (status) {
 224                         dev_err(&port->dev,
 225                                 "%s - failed submitting write urb, error %d\n",
 226                                 __func__, status);
 227                         goto error;
 228                 }
 229
 230                 /* This urb is the responsibility of the host driver now */
 231                 usb_free_urb(urb);
 232                 dbg("%s write: %d", __func__, towrite);
 233                 count -= towrite;
 234                 bwrite += towrite;
 235         }
 236         return bwrite;
 237
 238 error:
 239         usb_free_urb(urb);
 240 error_no_urb:
 241         kfree(buffer);
 242 error_no_buffer:
 243         spin_lock_irqsave(&port->lock, flags);
 244         port->urbs_in_flight--;
 245         port->tx_bytes_flight -= towrite;
 246         spin_unlock_irqrestore(&port->lock, flags);
 247         return bwrite;
 248 }
 249
 250 /**
 251  * usb_serial_generic_write_start - kick off an URB write
 252  * @port:       Pointer to the &struct usb_serial_port data
 253  *
 254  * Returns the number of bytes queued on success. This will be zero if there
 255  * was nothing to send. Otherwise, it returns a negative errno value
 256  */
 257 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 258 {
 259         unsigned char *data;
 260         int result;
 261         int count;
 262         unsigned long flags;
 263         bool start_io;
 264
 265         /* Atomically determine whether we can and need to start a USB
 266          * operation. */
 267         spin_lock_irqsave(&port->lock, flags);
 268         if (port->write_urb_busy)
 269                 start_io = false;
 270         else {
 271                 start_io = (kfifo_len(&port->write_fifo) != 0);
 272                 port->write_urb_busy = start_io;
 273         }
 274         spin_unlock_irqrestore(&port->lock, flags);
 275
 276         if (!start_io)
 277                 return 0;
 278
 279         data = port->write_urb->transfer_buffer;
 280         count = kfifo_out_locked(&port->write_fifo, data, port->bulk_out_size, &port->lock);
 281         usb_serial_debug_data(debug, &port->dev, __func__, count, data);
 282
 283         port->write_urb->transfer_buffer_length = count;
 284
 285         /* send the data out the bulk port */
 286         result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
 287         if (result) {
 288                 dev_err(&port->dev,
 289                         "%s - failed submitting write urb, error %d\n",
 290                                                 __func__, result);
 291                 /* don't have to grab the lock here, as we will
 292                    retry if != 0 */
 293                 port->write_urb_busy = 0;
 294                 return result;
 295         }
 296
 297         spin_lock_irqsave(&port->lock, flags);
 298         port->tx_bytes_flight += count;
 299         spin_unlock_irqrestore(&port->lock, flags);
 300
 301         return count;
 302 }
 303
 304 /**
 305  * usb_serial_generic_write - generic write function for serial USB devices
 306  * @tty:        Pointer to &struct tty_struct for the device
 307  * @port:       Pointer to the &usb_serial_port structure for the device
 308  * @buf:        Pointer to the data to write
 309  * @count:      Number of bytes to write
 310  *
 311  * Returns the number of characters actually written, which may be anything
 312  * from zero to @count. If an error occurs, it returns the negative errno
 313  * value.
 314  */
 315 int usb_serial_generic_write(struct tty_struct *tty,
 316         struct usb_serial_port *port, const unsigned char *buf, int count)
 317 {
 318         struct usb_serial *serial = port->serial;
 319         int result;
 320
 321         dbg("%s - port %d", __func__, port->number);
 322
 323         /* only do something if we have a bulk out endpoint */
 324         if (!port->bulk_out_size)
 325                 return -ENODEV;
 326
 327         if (count == 0) {
 328                 dbg("%s - write request of 0 bytes", __func__);
 329                 return 0;
 330         }
 331
 332         if (serial->type->max_in_flight_urbs)
 333                 return usb_serial_multi_urb_write(tty, port,
 334                                                   buf, count);
 335
 336         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 337         result = usb_serial_generic_write_start(port);
 338
 339         if (result >= 0)
 340                 result = count;
 341
 342         return result;
 343 }
 344 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 345
 346 int usb_serial_generic_write_room(struct tty_struct *tty)
 347 {
 348         struct usb_serial_port *port = tty->driver_data;
 349         struct usb_serial *serial = port->serial;
 350         unsigned long flags;
 351         int room = 0;
 352
 353         dbg("%s - port %d", __func__, port->number);
 354
 355         if (!port->bulk_out_size)
 356                 return 0;
 357
 358         spin_lock_irqsave(&port->lock, flags);
 359         if (serial->type->max_in_flight_urbs) {
 360                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
 361                         room = port->bulk_out_size *
 362                                 (serial->type->max_in_flight_urbs -
 363                                  port->urbs_in_flight);
 364         } else {
 365                 room = kfifo_avail(&port->write_fifo);
 366         }
 367         spin_unlock_irqrestore(&port->lock, flags);
 368
 369         dbg("%s - returns %d", __func__, room);
 370         return room;
 371 }
 372
 373 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 374 {
 375         struct usb_serial_port *port = tty->driver_data;
 376         struct usb_serial *serial = port->serial;
 377         unsigned long flags;
 378         int chars;
 379
 380         dbg("%s - port %d", __func__, port->number);
 381
 382         if (!port->bulk_out_size)
 383                 return 0;
 384
 385         spin_lock_irqsave(&port->lock, flags);
 386         if (serial->type->max_in_flight_urbs)
 387                 chars = port->tx_bytes_flight;
 388         else
 389                 chars = kfifo_len(&port->write_fifo) + port->tx_bytes_flight;
 390         spin_unlock_irqrestore(&port->lock, flags);
 391
 392         dbg("%s - returns %d", __func__, chars);
 393         return chars;
 394 }
 395
 396 int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 397                                         gfp_t mem_flags)
 398 {
 399         int result;
 400
 401         result = usb_submit_urb(port->read_urb, mem_flags);
 402         if (result && result != -EPERM) {
 403                 dev_err(&port->dev,
 404                         "%s - failed submitting read urb, error %d\n",
 405                                                         __func__, result);
 406         }
 407         return result;
 408 }
 409 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
 410
 411 /* Push data to tty layer and resubmit the bulk read URB */
 412 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 413 {
 414         struct urb *urb = port->read_urb;
 415         struct tty_struct *tty = tty_port_tty_get(&port->port);
 416         char *ch = (char *)urb->transfer_buffer;
 417         int i;
 418
 419         if (!tty)
 420                 goto done;
 421
 422         /* The per character mucking around with sysrq path it too slow for
 423            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 424            where the USB serial is not a console anyway */
 425         if (!port->port.console || !port->sysrq)
 426                 tty_insert_flip_string(tty, ch, urb->actual_length);
 427         else {
 428                 /* Push data to tty */
 429                 for (i = 0; i < urb->actual_length; i++, ch++) {
 430                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 431                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 432                 }
 433         }
 434         tty_flip_buffer_push(tty);
 435         tty_kref_put(tty);
 436 done:
 437         usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
 438 }
 439
 440 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 441 {
 442         struct usb_serial_port *port = urb->context;
 443         unsigned char *data = urb->transfer_buffer;
 444         int status = urb->status;
 445         unsigned long flags;
 446
 447         dbg("%s - port %d", __func__, port->number);
 448
 449         if (unlikely(status != 0)) {
 450                 dbg("%s - nonzero read bulk status received: %d",
 451                     __func__, status);
 452                 return;
 453         }
 454
 455         usb_serial_debug_data(debug, &port->dev, __func__,
 456                                                 urb->actual_length, data);
 457
 458         /* Throttle the device if requested by tty */
 459         spin_lock_irqsave(&port->lock, flags);
 460         port->throttled = port->throttle_req;
 461         if (!port->throttled) {
 462                 spin_unlock_irqrestore(&port->lock, flags);
 463                 flush_and_resubmit_read_urb(port);
 464         } else
 465                 spin_unlock_irqrestore(&port->lock, flags);
 466 }
 467 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 468
 469 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 470 {
 471         unsigned long flags;
 472         struct usb_serial_port *port = urb->context;
 473         int status = urb->status;
 474
 475         dbg("%s - port %d", __func__, port->number);
 476
 477         if (port->serial->type->max_in_flight_urbs) {
 478                 kfree(urb->transfer_buffer);
 479
 480                 spin_lock_irqsave(&port->lock, flags);
 481                 --port->urbs_in_flight;
 482                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 483                 if (port->urbs_in_flight < 0)
 484                         port->urbs_in_flight = 0;
 485                 spin_unlock_irqrestore(&port->lock, flags);
 486         } else {
 487                 spin_lock_irqsave(&port->lock, flags);
 488                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 489                 port->write_urb_busy = 0;
 490                 spin_unlock_irqrestore(&port->lock, flags);
 491
 492                 if (status) {
 493                         spin_lock_irqsave(&port->lock, flags);
 494                         kfifo_reset_out(&port->write_fifo);
 495                         spin_unlock_irqrestore(&port->lock, flags);
 496                 } else {
 497                         usb_serial_generic_write_start(port);
 498                 }
 499         }
 500
 501         if (status)
 502                 dbg("%s - non-zero urb status: %d", __func__, status);
 503
 504         usb_serial_port_softint(port);
 505 }
 506 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 507
 508 void usb_serial_generic_throttle(struct tty_struct *tty)
 509 {
 510         struct usb_serial_port *port = tty->driver_data;
 511         unsigned long flags;
 512
 513         dbg("%s - port %d", __func__, port->number);
 514
 515         /* Set the throttle request flag. It will be picked up
 516          * by usb_serial_generic_read_bulk_callback(). */
 517         spin_lock_irqsave(&port->lock, flags);
 518         port->throttle_req = 1;
 519         spin_unlock_irqrestore(&port->lock, flags);
 520 }
 521
 522 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 523 {
 524         struct usb_serial_port *port = tty->driver_data;
 525         int was_throttled;
 526         unsigned long flags;
 527
 528         dbg("%s - port %d", __func__, port->number);
 529
 530         /* Clear the throttle flags */
 531         spin_lock_irqsave(&port->lock, flags);
 532         was_throttled = port->throttled;
 533         port->throttled = port->throttle_req = 0;
 534         spin_unlock_irqrestore(&port->lock, flags);
 535
 536         if (was_throttled) {
 537                 /* Resume reading from device */
 538                 flush_and_resubmit_read_urb(port);
 539         }
 540 }
 541
 542 #ifdef CONFIG_MAGIC_SYSRQ
 543 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 544                         struct usb_serial_port *port, unsigned int ch)
 545 {
 546         if (port->sysrq && port->port.console) {
 547                 if (ch && time_before(jiffies, port->sysrq)) {
 548                         handle_sysrq(ch, tty);
 549                         port->sysrq = 0;
 550                         return 1;
 551                 }
 552                 port->sysrq = 0;
 553         }
 554         return 0;
 555 }
 556 #else
 557 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 558                         struct usb_serial_port *port, unsigned int ch)
 559 {
 560         return 0;
 561 }
 562 #endif
 563 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 564
 565 int usb_serial_handle_break(struct usb_serial_port *port)
 566 {
 567         if (!port->sysrq) {
 568                 port->sysrq = jiffies + HZ*5;
 569                 return 1;
 570         }
 571         port->sysrq = 0;
 572         return 0;
 573 }
 574 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 575
 576 int usb_serial_generic_resume(struct usb_serial *serial)
 577 {
 578         struct usb_serial_port *port;
 579         int i, c = 0, r;
 580
 581         for (i = 0; i < serial->num_ports; i++) {
 582                 port = serial->port[i];
 583                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 584                         continue;
 585
 586                 if (port->read_urb) {
 587                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 588                         if (r < 0)
 589                                 c++;
 590                 }
 591
 592                 if (port->write_urb) {
 593                         r = usb_serial_generic_write_start(port);
 594                         if (r < 0)
 595                                 c++;
 596                 }
 597         }
 598
 599         return c ? -EIO : 0;
 600 }
 601 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 602
 603 void usb_serial_generic_disconnect(struct usb_serial *serial)
 604 {
 605         int i;
 606
 607         dbg("%s", __func__);
 608
 609         /* stop reads and writes on all ports */
 610         for (i = 0; i < serial->num_ports; ++i)
 611                 generic_cleanup(serial->port[i]);
 612 }
 613
 614 void usb_serial_generic_release(struct usb_serial *serial)
 615 {
 616         dbg("%s", __func__);
 617 }