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                 return result;
 313         }
 314
 315         spin_lock_irqsave(&port->lock, flags);
 316         port->tx_bytes_flight += count;
 317         spin_unlock_irqrestore(&port->lock, flags);
 318
 319         return count;
 320 }
 321
 322 /**
 323  * usb_serial_generic_write - generic write function for serial USB devices
 324  * @tty:        Pointer to &struct tty_struct for the device
 325  * @port:       Pointer to the &usb_serial_port structure for the device
 326  * @buf:        Pointer to the data to write
 327  * @count:      Number of bytes to write
 328  *
 329  * Returns the number of characters actually written, which may be anything
 330  * from zero to @count. If an error occurs, it returns the negative errno
 331  * value.
 332  */
 333 int usb_serial_generic_write(struct tty_struct *tty,
 334         struct usb_serial_port *port, const unsigned char *buf, int count)
 335 {
 336         struct usb_serial *serial = port->serial;
 337         int result;
 338
 339         dbg("%s - port %d", __func__, port->number);
 340
 341         /* only do something if we have a bulk out endpoint */
 342         if (!port->bulk_out_size)
 343                 return -ENODEV;
 344
 345         if (count == 0) {
 346                 dbg("%s - write request of 0 bytes", __func__);
 347                 return 0;
 348         }
 349
 350         if (serial->type->max_in_flight_urbs)
 351                 return usb_serial_multi_urb_write(tty, port,
 352                                                   buf, count);
 353
 354         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 355         result = usb_serial_generic_write_start(port);
 356
 357         if (result >= 0)
 358                 result = count;
 359
 360         return result;
 361 }
 362 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 363
 364 int usb_serial_generic_write_room(struct tty_struct *tty)
 365 {
 366         struct usb_serial_port *port = tty->driver_data;
 367         struct usb_serial *serial = port->serial;
 368         unsigned long flags;
 369         int room = 0;
 370
 371         dbg("%s - port %d", __func__, port->number);
 372
 373         if (!port->bulk_out_size)
 374                 return 0;
 375
 376         spin_lock_irqsave(&port->lock, flags);
 377         if (serial->type->max_in_flight_urbs) {
 378                 if (port->urbs_in_flight < serial->type->max_in_flight_urbs)
 379                         room = port->bulk_out_size *
 380                                 (serial->type->max_in_flight_urbs -
 381                                  port->urbs_in_flight);
 382         } else {
 383                 room = kfifo_avail(&port->write_fifo);
 384         }
 385         spin_unlock_irqrestore(&port->lock, flags);
 386
 387         dbg("%s - returns %d", __func__, room);
 388         return room;
 389 }
 390
 391 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 392 {
 393         struct usb_serial_port *port = tty->driver_data;
 394         struct usb_serial *serial = port->serial;
 395         unsigned long flags;
 396         int chars;
 397
 398         dbg("%s - port %d", __func__, port->number);
 399
 400         if (!port->bulk_out_size)
 401                 return 0;
 402
 403         spin_lock_irqsave(&port->lock, flags);
 404         if (serial->type->max_in_flight_urbs)
 405                 chars = port->tx_bytes_flight;
 406         else
 407                 chars = kfifo_len(&port->write_fifo) + port->tx_bytes_flight;
 408         spin_unlock_irqrestore(&port->lock, flags);
 409
 410         dbg("%s - returns %d", __func__, chars);
 411         return chars;
 412 }
 413
 414
 415 void usb_serial_generic_resubmit_read_urb(struct usb_serial_port *port,
 416                         gfp_t mem_flags)
 417 {
 418         struct urb *urb = port->read_urb;
 419         struct usb_serial *serial = port->serial;
 420         int result;
 421
 422         /* Continue reading from device */
 423         usb_fill_bulk_urb(urb, serial->dev,
 424                            usb_rcvbulkpipe(serial->dev,
 425                                         port->bulk_in_endpointAddress),
 426                            urb->transfer_buffer,
 427                            urb->transfer_buffer_length,
 428                            ((serial->type->read_bulk_callback) ?
 429                              serial->type->read_bulk_callback :
 430                              usb_serial_generic_read_bulk_callback), port);
 431
 432         result = usb_submit_urb(urb, mem_flags);
 433         if (result && result != -EPERM) {
 434                 dev_err(&port->dev,
 435                         "%s - failed resubmitting read urb, error %d\n",
 436                                                         __func__, result);
 437         }
 438 }
 439 EXPORT_SYMBOL_GPL(usb_serial_generic_resubmit_read_urb);
 440
 441 /* Push data to tty layer and resubmit the bulk read URB */
 442 static void flush_and_resubmit_read_urb(struct usb_serial_port *port)
 443 {
 444         struct urb *urb = port->read_urb;
 445         struct tty_struct *tty = tty_port_tty_get(&port->port);
 446         char *ch = (char *)urb->transfer_buffer;
 447         int i;
 448
 449         if (!tty)
 450                 goto done;
 451
 452         /* The per character mucking around with sysrq path it too slow for
 453            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 454            where the USB serial is not a console anyway */
 455         if (!port->port.console || !port->sysrq)
 456                 tty_insert_flip_string(tty, ch, urb->actual_length);
 457         else {
 458                 /* Push data to tty */
 459                 for (i = 0; i < urb->actual_length; i++, ch++) {
 460                         if (!usb_serial_handle_sysrq_char(tty, port, *ch))
 461                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 462                 }
 463         }
 464         tty_flip_buffer_push(tty);
 465         tty_kref_put(tty);
 466 done:
 467         usb_serial_generic_resubmit_read_urb(port, GFP_ATOMIC);
 468 }
 469
 470 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 471 {
 472         struct usb_serial_port *port = urb->context;
 473         unsigned char *data = urb->transfer_buffer;
 474         int status = urb->status;
 475         unsigned long flags;
 476
 477         dbg("%s - port %d", __func__, port->number);
 478
 479         if (unlikely(status != 0)) {
 480                 dbg("%s - nonzero read bulk status received: %d",
 481                     __func__, status);
 482                 return;
 483         }
 484
 485         usb_serial_debug_data(debug, &port->dev, __func__,
 486                                                 urb->actual_length, data);
 487
 488         /* Throttle the device if requested by tty */
 489         spin_lock_irqsave(&port->lock, flags);
 490         port->throttled = port->throttle_req;
 491         if (!port->throttled) {
 492                 spin_unlock_irqrestore(&port->lock, flags);
 493                 flush_and_resubmit_read_urb(port);
 494         } else
 495                 spin_unlock_irqrestore(&port->lock, flags);
 496 }
 497 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 498
 499 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 500 {
 501         unsigned long flags;
 502         struct usb_serial_port *port = urb->context;
 503         int status = urb->status;
 504
 505         dbg("%s - port %d", __func__, port->number);
 506
 507         if (port->serial->type->max_in_flight_urbs) {
 508                 kfree(urb->transfer_buffer);
 509
 510                 spin_lock_irqsave(&port->lock, flags);
 511                 --port->urbs_in_flight;
 512                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 513                 if (port->urbs_in_flight < 0)
 514                         port->urbs_in_flight = 0;
 515                 spin_unlock_irqrestore(&port->lock, flags);
 516         } else {
 517                 spin_lock_irqsave(&port->lock, flags);
 518                 port->tx_bytes_flight -= urb->transfer_buffer_length;
 519                 port->write_urb_busy = 0;
 520                 spin_unlock_irqrestore(&port->lock, flags);
 521
 522                 if (status) {
 523                         spin_lock_irqsave(&port->lock, flags);
 524                         kfifo_reset_out(&port->write_fifo);
 525                         spin_unlock_irqrestore(&port->lock, flags);
 526                 } else {
 527                         usb_serial_generic_write_start(port);
 528                 }
 529         }
 530
 531         if (status)
 532                 dbg("%s - non-zero urb status: %d", __func__, status);
 533
 534         usb_serial_port_softint(port);
 535 }
 536 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 537
 538 void usb_serial_generic_throttle(struct tty_struct *tty)
 539 {
 540         struct usb_serial_port *port = tty->driver_data;
 541         unsigned long flags;
 542
 543         dbg("%s - port %d", __func__, port->number);
 544
 545         /* Set the throttle request flag. It will be picked up
 546          * by usb_serial_generic_read_bulk_callback(). */
 547         spin_lock_irqsave(&port->lock, flags);
 548         port->throttle_req = 1;
 549         spin_unlock_irqrestore(&port->lock, flags);
 550 }
 551
 552 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 553 {
 554         struct usb_serial_port *port = tty->driver_data;
 555         int was_throttled;
 556         unsigned long flags;
 557
 558         dbg("%s - port %d", __func__, port->number);
 559
 560         /* Clear the throttle flags */
 561         spin_lock_irqsave(&port->lock, flags);
 562         was_throttled = port->throttled;
 563         port->throttled = port->throttle_req = 0;
 564         spin_unlock_irqrestore(&port->lock, flags);
 565
 566         if (was_throttled) {
 567                 /* Resume reading from device */
 568                 flush_and_resubmit_read_urb(port);
 569         }
 570 }
 571
 572 #ifdef CONFIG_MAGIC_SYSRQ
 573 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 574                         struct usb_serial_port *port, unsigned int ch)
 575 {
 576         if (port->sysrq && port->port.console) {
 577                 if (ch && time_before(jiffies, port->sysrq)) {
 578                         handle_sysrq(ch, tty);
 579                         port->sysrq = 0;
 580                         return 1;
 581                 }
 582                 port->sysrq = 0;
 583         }
 584         return 0;
 585 }
 586 #else
 587 int usb_serial_handle_sysrq_char(struct tty_struct *tty,
 588                         struct usb_serial_port *port, unsigned int ch)
 589 {
 590         return 0;
 591 }
 592 #endif
 593 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 594
 595 int usb_serial_handle_break(struct usb_serial_port *port)
 596 {
 597         if (!port->sysrq) {
 598                 port->sysrq = jiffies + HZ*5;
 599                 return 1;
 600         }
 601         port->sysrq = 0;
 602         return 0;
 603 }
 604 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 605
 606 int usb_serial_generic_resume(struct usb_serial *serial)
 607 {
 608         struct usb_serial_port *port;
 609         int i, c = 0, r;
 610
 611         for (i = 0; i < serial->num_ports; i++) {
 612                 port = serial->port[i];
 613                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 614                         continue;
 615
 616                 if (port->read_urb) {
 617                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 618                         if (r < 0)
 619                                 c++;
 620                 }
 621
 622                 if (port->write_urb) {
 623                         r = usb_serial_generic_write_start(port);
 624                         if (r < 0)
 625                                 c++;
 626                 }
 627         }
 628
 629         return c ? -EIO : 0;
 630 }
 631 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 632
 633 void usb_serial_generic_disconnect(struct usb_serial *serial)
 634 {
 635         int i;
 636
 637         dbg("%s", __func__);
 638
 639         /* stop reads and writes on all ports */
 640         for (i = 0; i < serial->num_ports; ++i)
 641                 generic_cleanup(serial->port[i]);
 642 }
 643
 644 void usb_serial_generic_release(struct usb_serial *serial)
 645 {
 646         dbg("%s", __func__);
 647 }