drivers/usb/serial/generic.c

   1 /*
   2  * USB Serial Converter Generic functions
   3  *
   4  * Copyright (C) 2010 - 2011 Johan Hovold (jhovold@gmail.com)
   5  * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
   6  *
   7  *      This program is free software; you can redistribute it and/or
   8  *      modify it under the terms of the GNU General Public License version
   9  *      2 as published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/errno.h>
  15 #include <linux/slab.h>
  16 #include <linux/sysrq.h>
  17 #include <linux/tty.h>
  18 #include <linux/tty_flip.h>
  19 #include <linux/module.h>
  20 #include <linux/moduleparam.h>
  21 #include <linux/usb.h>
  22 #include <linux/usb/serial.h>
  23 #include <linux/uaccess.h>
  24 #include <linux/kfifo.h>
  25 #include <linux/serial.h>
  26
  27 static int debug;
  28
  29 #ifdef CONFIG_USB_SERIAL_GENERIC
  30
  31 static int generic_probe(struct usb_interface *interface,
  32                          const struct usb_device_id *id);
  33
  34 static __u16 vendor  = 0x05f9;
  35 static __u16 product = 0xffff;
  36
  37 module_param(vendor, ushort, 0);
  38 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  39
  40 module_param(product, ushort, 0);
  41 MODULE_PARM_DESC(product, "User specified USB idProduct");
  42
  43 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  44
  45 /* we want to look at all devices, as the vendor/product id can change
  46  * depending on the command line argument */
  47 static const struct usb_device_id generic_serial_ids[] = {
  48         {.driver_info = 42},
  49         {}
  50 };
  51
  52 static struct usb_driver generic_driver = {
  53         .name =         "usbserial_generic",
  54         .probe =        generic_probe,
  55         .disconnect =   usb_serial_disconnect,
  56         .id_table =     generic_serial_ids,
  57         .no_dynamic_id =        1,
  58 };
  59
  60 /* All of the device info needed for the Generic Serial Converter */
  61 struct usb_serial_driver usb_serial_generic_device = {
  62         .driver = {
  63                 .owner =        THIS_MODULE,
  64                 .name =         "generic",
  65         },
  66         .id_table =             generic_device_ids,
  67         .usb_driver =           &generic_driver,
  68         .num_ports =            1,
  69         .disconnect =           usb_serial_generic_disconnect,
  70         .release =              usb_serial_generic_release,
  71         .throttle =             usb_serial_generic_throttle,
  72         .unthrottle =           usb_serial_generic_unthrottle,
  73         .resume =               usb_serial_generic_resume,
  74 };
  75
  76 static int generic_probe(struct usb_interface *interface,
  77                                const struct usb_device_id *id)
  78 {
  79         const struct usb_device_id *id_pattern;
  80
  81         id_pattern = usb_match_id(interface, generic_device_ids);
  82         if (id_pattern != NULL)
  83                 return usb_serial_probe(interface, id);
  84         return -ENODEV;
  85 }
  86 #endif
  87
  88 int usb_serial_generic_register(int _debug)
  89 {
  90         int retval = 0;
  91
  92         debug = _debug;
  93 #ifdef CONFIG_USB_SERIAL_GENERIC
  94         generic_device_ids[0].idVendor = vendor;
  95         generic_device_ids[0].idProduct = product;
  96         generic_device_ids[0].match_flags =
  97                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  98
  99         /* register our generic driver with ourselves */
 100         retval = usb_serial_register(&usb_serial_generic_device);
 101         if (retval)
 102                 goto exit;
 103         retval = usb_register(&generic_driver);
 104         if (retval)
 105                 usb_serial_deregister(&usb_serial_generic_device);
 106 exit:
 107 #endif
 108         return retval;
 109 }
 110
 111 void usb_serial_generic_deregister(void)
 112 {
 113 #ifdef CONFIG_USB_SERIAL_GENERIC
 114         /* remove our generic driver */
 115         usb_deregister(&generic_driver);
 116         usb_serial_deregister(&usb_serial_generic_device);
 117 #endif
 118 }
 119
 120 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 121 {
 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                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 136
 137         return result;
 138 }
 139 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 140
 141 static void generic_cleanup(struct usb_serial_port *port)
 142 {
 143         struct usb_serial *serial = port->serial;
 144         unsigned long flags;
 145         int i;
 146
 147         dbg("%s - port %d", __func__, port->number);
 148
 149         if (serial->dev) {
 150                 /* shutdown any bulk transfers that might be going on */
 151                 if (port->bulk_out_size) {
 152                         usb_kill_urb(port->write_urb);
 153                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 154                                 usb_kill_urb(port->write_urbs[i]);
 155
 156                         spin_lock_irqsave(&port->lock, flags);
 157                         kfifo_reset_out(&port->write_fifo);
 158                         spin_unlock_irqrestore(&port->lock, flags);
 159                 }
 160                 if (port->bulk_in_size) {
 161                         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 162                                 usb_kill_urb(port->read_urbs[i]);
 163                 }
 164         }
 165 }
 166
 167 void usb_serial_generic_close(struct usb_serial_port *port)
 168 {
 169         dbg("%s - port %d", __func__, port->number);
 170         generic_cleanup(port);
 171 }
 172 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 173
 174 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 175                                                 void *dest, size_t size)
 176 {
 177         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 178 }
 179
 180 /**
 181  * usb_serial_generic_write_start - kick off an URB write
 182  * @port:       Pointer to the &struct usb_serial_port data
 183  *
 184  * Returns zero on success, or a negative errno value
 185  */
 186 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 187 {
 188         struct urb *urb;
 189         int count, result;
 190         unsigned long flags;
 191         int i;
 192
 193         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 194                 return 0;
 195 retry:
 196         spin_lock_irqsave(&port->lock, flags);
 197         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 198                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 199                 spin_unlock_irqrestore(&port->lock, flags);
 200                 return 0;
 201         }
 202         i = (int)find_first_bit(&port->write_urbs_free,
 203                                                 ARRAY_SIZE(port->write_urbs));
 204         spin_unlock_irqrestore(&port->lock, flags);
 205
 206         urb = port->write_urbs[i];
 207         count = port->serial->type->prepare_write_buffer(port,
 208                                                 urb->transfer_buffer,
 209                                                 port->bulk_out_size);
 210         urb->transfer_buffer_length = count;
 211         usb_serial_debug_data(debug, &port->dev, __func__, count,
 212                                                 urb->transfer_buffer);
 213         spin_lock_irqsave(&port->lock, flags);
 214         port->tx_bytes += count;
 215         spin_unlock_irqrestore(&port->lock, flags);
 216
 217         clear_bit(i, &port->write_urbs_free);
 218         result = usb_submit_urb(urb, GFP_ATOMIC);
 219         if (result) {
 220                 if (!port->port.console) {
 221                         dev_err(&port->dev, "%s - error submitting urb: %d\n",
 222                                                 __func__, result);
 223                 }
 224                 set_bit(i, &port->write_urbs_free);
 225                 spin_lock_irqsave(&port->lock, flags);
 226                 port->tx_bytes -= count;
 227                 spin_unlock_irqrestore(&port->lock, flags);
 228
 229                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 230                 return result;
 231         }
 232
 233         /* Try sending off another urb, unless in irq context (in which case
 234          * there will be no free urb). */
 235         if (!in_irq())
 236                 goto retry;
 237
 238         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 239
 240         return 0;
 241 }
 242
 243 /**
 244  * usb_serial_generic_write - generic write function for serial USB devices
 245  * @tty:        Pointer to &struct tty_struct for the device
 246  * @port:       Pointer to the &usb_serial_port structure for the device
 247  * @buf:        Pointer to the data to write
 248  * @count:      Number of bytes to write
 249  *
 250  * Returns the number of characters actually written, which may be anything
 251  * from zero to @count. If an error occurs, it returns the negative errno
 252  * value.
 253  */
 254 int usb_serial_generic_write(struct tty_struct *tty,
 255         struct usb_serial_port *port, const unsigned char *buf, int count)
 256 {
 257         int result;
 258
 259         dbg("%s - port %d", __func__, port->number);
 260
 261         /* only do something if we have a bulk out endpoint */
 262         if (!port->bulk_out_size)
 263                 return -ENODEV;
 264
 265         if (!count)
 266                 return 0;
 267
 268         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 269         result = usb_serial_generic_write_start(port);
 270         if (result)
 271                 return result;
 272
 273         return count;
 274 }
 275 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 276
 277 int usb_serial_generic_write_room(struct tty_struct *tty)
 278 {
 279         struct usb_serial_port *port = tty->driver_data;
 280         unsigned long flags;
 281         int room;
 282
 283         dbg("%s - port %d", __func__, port->number);
 284
 285         if (!port->bulk_out_size)
 286                 return 0;
 287
 288         spin_lock_irqsave(&port->lock, flags);
 289         room = kfifo_avail(&port->write_fifo);
 290         spin_unlock_irqrestore(&port->lock, flags);
 291
 292         dbg("%s - returns %d", __func__, room);
 293         return room;
 294 }
 295
 296 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 297 {
 298         struct usb_serial_port *port = tty->driver_data;
 299         unsigned long flags;
 300         int chars;
 301
 302         dbg("%s - port %d", __func__, port->number);
 303
 304         if (!port->bulk_out_size)
 305                 return 0;
 306
 307         spin_lock_irqsave(&port->lock, flags);
 308         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 309         spin_unlock_irqrestore(&port->lock, flags);
 310
 311         dbg("%s - returns %d", __func__, chars);
 312         return chars;
 313 }
 314
 315 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 316                                                 int index, gfp_t mem_flags)
 317 {
 318         int res;
 319
 320         if (!test_and_clear_bit(index, &port->read_urbs_free))
 321                 return 0;
 322
 323         dbg("%s - port %d, urb %d\n", __func__, port->number, index);
 324
 325         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 326         if (res) {
 327                 if (res != -EPERM) {
 328                         dev_err(&port->dev,
 329                                         "%s - usb_submit_urb failed: %d\n",
 330                                         __func__, res);
 331                 }
 332                 set_bit(index, &port->read_urbs_free);
 333                 return res;
 334         }
 335
 336         return 0;
 337 }
 338
 339 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 340                                         gfp_t mem_flags)
 341 {
 342         int res;
 343         int i;
 344
 345         dbg("%s - port %d", __func__, port->number);
 346
 347         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 348                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 349                 if (res)
 350                         goto err;
 351         }
 352
 353         return 0;
 354 err:
 355         for (; i >= 0; --i)
 356                 usb_kill_urb(port->read_urbs[i]);
 357
 358         return res;
 359 }
 360 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 361
 362 void usb_serial_generic_process_read_urb(struct urb *urb)
 363 {
 364         struct usb_serial_port *port = urb->context;
 365         struct tty_struct *tty;
 366         char *ch = (char *)urb->transfer_buffer;
 367         int i;
 368
 369         if (!urb->actual_length)
 370                 return;
 371
 372         tty = tty_port_tty_get(&port->port);
 373         if (!tty)
 374                 return;
 375
 376         /* The per character mucking around with sysrq path it too slow for
 377            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 378            where the USB serial is not a console anyway */
 379         if (!port->port.console || !port->sysrq)
 380                 tty_insert_flip_string(tty, ch, urb->actual_length);
 381         else {
 382                 for (i = 0; i < urb->actual_length; i++, ch++) {
 383                         if (!usb_serial_handle_sysrq_char(port, *ch))
 384                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 385                 }
 386         }
 387         tty_flip_buffer_push(tty);
 388         tty_kref_put(tty);
 389 }
 390 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 391
 392 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 393 {
 394         struct usb_serial_port *port = urb->context;
 395         unsigned char *data = urb->transfer_buffer;
 396         unsigned long flags;
 397         int i;
 398
 399         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 400                 if (urb == port->read_urbs[i])
 401                         break;
 402         }
 403         set_bit(i, &port->read_urbs_free);
 404
 405         dbg("%s - port %d, urb %d, len %d\n", __func__, port->number, i,
 406                                                         urb->actual_length);
 407         if (urb->status) {
 408                 dbg("%s - non-zero urb status: %d\n", __func__, urb->status);
 409                 return;
 410         }
 411
 412         usb_serial_debug_data(debug, &port->dev, __func__,
 413                                                 urb->actual_length, data);
 414         port->serial->type->process_read_urb(urb);
 415
 416         /* Throttle the device if requested by tty */
 417         spin_lock_irqsave(&port->lock, flags);
 418         port->throttled = port->throttle_req;
 419         if (!port->throttled) {
 420                 spin_unlock_irqrestore(&port->lock, flags);
 421                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 422         } else
 423                 spin_unlock_irqrestore(&port->lock, flags);
 424 }
 425 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 426
 427 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 428 {
 429         unsigned long flags;
 430         struct usb_serial_port *port = urb->context;
 431         int status = urb->status;
 432         int i;
 433
 434         dbg("%s - port %d", __func__, port->number);
 435
 436         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 437                 if (port->write_urbs[i] == urb)
 438                         break;
 439
 440         spin_lock_irqsave(&port->lock, flags);
 441         port->tx_bytes -= urb->transfer_buffer_length;
 442         set_bit(i, &port->write_urbs_free);
 443         spin_unlock_irqrestore(&port->lock, flags);
 444
 445         if (status) {
 446                 dbg("%s - non-zero urb status: %d", __func__, status);
 447
 448                 spin_lock_irqsave(&port->lock, flags);
 449                 kfifo_reset_out(&port->write_fifo);
 450                 spin_unlock_irqrestore(&port->lock, flags);
 451         } else {
 452                 usb_serial_generic_write_start(port);
 453         }
 454
 455         usb_serial_port_softint(port);
 456 }
 457 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 458
 459 void usb_serial_generic_throttle(struct tty_struct *tty)
 460 {
 461         struct usb_serial_port *port = tty->driver_data;
 462         unsigned long flags;
 463
 464         dbg("%s - port %d", __func__, port->number);
 465
 466         /* Set the throttle request flag. It will be picked up
 467          * by usb_serial_generic_read_bulk_callback(). */
 468         spin_lock_irqsave(&port->lock, flags);
 469         port->throttle_req = 1;
 470         spin_unlock_irqrestore(&port->lock, flags);
 471 }
 472 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 473
 474 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 475 {
 476         struct usb_serial_port *port = tty->driver_data;
 477         int was_throttled;
 478
 479         dbg("%s - port %d", __func__, port->number);
 480
 481         /* Clear the throttle flags */
 482         spin_lock_irq(&port->lock);
 483         was_throttled = port->throttled;
 484         port->throttled = port->throttle_req = 0;
 485         spin_unlock_irq(&port->lock);
 486
 487         if (was_throttled)
 488                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 489 }
 490 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 491
 492 #ifdef CONFIG_MAGIC_SYSRQ
 493 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 494 {
 495         if (port->sysrq && port->port.console) {
 496                 if (ch && time_before(jiffies, port->sysrq)) {
 497                         handle_sysrq(ch);
 498                         port->sysrq = 0;
 499                         return 1;
 500                 }
 501                 port->sysrq = 0;
 502         }
 503         return 0;
 504 }
 505 #else
 506 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 507 {
 508         return 0;
 509 }
 510 #endif
 511 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 512
 513 int usb_serial_handle_break(struct usb_serial_port *port)
 514 {
 515         if (!port->sysrq) {
 516                 port->sysrq = jiffies + HZ*5;
 517                 return 1;
 518         }
 519         port->sysrq = 0;
 520         return 0;
 521 }
 522 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 523
 524 /**
 525  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 526  *      @port: usb_serial_port structure for the open port
 527  *      @tty: tty_struct structure for the port
 528  *      @status: new carrier detect status, nonzero if active
 529  */
 530 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 531                                 struct tty_struct *tty, unsigned int status)
 532 {
 533         struct tty_port *port = &usb_port->port;
 534
 535         dbg("%s - port %d, status %d", __func__, usb_port->number, status);
 536
 537         if (status)
 538                 wake_up_interruptible(&port->open_wait);
 539         else if (tty && !C_CLOCAL(tty))
 540                 tty_hangup(tty);
 541 }
 542 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 543
 544 int usb_serial_generic_resume(struct usb_serial *serial)
 545 {
 546         struct usb_serial_port *port;
 547         int i, c = 0, r;
 548
 549         for (i = 0; i < serial->num_ports; i++) {
 550                 port = serial->port[i];
 551                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 552                         continue;
 553
 554                 if (port->bulk_in_size) {
 555                         r = usb_serial_generic_submit_read_urbs(port,
 556                                                                 GFP_NOIO);
 557                         if (r < 0)
 558                                 c++;
 559                 }
 560
 561                 if (port->bulk_out_size) {
 562                         r = usb_serial_generic_write_start(port);
 563                         if (r < 0)
 564                                 c++;
 565                 }
 566         }
 567
 568         return c ? -EIO : 0;
 569 }
 570 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 571
 572 void usb_serial_generic_disconnect(struct usb_serial *serial)
 573 {
 574         int i;
 575
 576         dbg("%s", __func__);
 577
 578         /* stop reads and writes on all ports */
 579         for (i = 0; i < serial->num_ports; ++i)
 580                 generic_cleanup(serial->port[i]);
 581 }
 582 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 583
 584 void usb_serial_generic_release(struct usb_serial *serial)
 585 {
 586         dbg("%s", __func__);
 587 }