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 };
  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         .num_ports =            1,
  67         .disconnect =           usb_serial_generic_disconnect,
  68         .release =              usb_serial_generic_release,
  69         .throttle =             usb_serial_generic_throttle,
  70         .unthrottle =           usb_serial_generic_unthrottle,
  71         .resume =               usb_serial_generic_resume,
  72 };
  73
  74 static struct usb_serial_driver * const serial_drivers[] = {
  75         &usb_serial_generic_device, NULL
  76 };
  77
  78 static int generic_probe(struct usb_interface *interface,
  79                                const struct usb_device_id *id)
  80 {
  81         const struct usb_device_id *id_pattern;
  82
  83         id_pattern = usb_match_id(interface, generic_device_ids);
  84         if (id_pattern != NULL)
  85                 return usb_serial_probe(interface, id);
  86         return -ENODEV;
  87 }
  88 #endif
  89
  90 int usb_serial_generic_register(int _debug)
  91 {
  92         int retval = 0;
  93
  94         debug = _debug;
  95 #ifdef CONFIG_USB_SERIAL_GENERIC
  96         generic_device_ids[0].idVendor = vendor;
  97         generic_device_ids[0].idProduct = product;
  98         generic_device_ids[0].match_flags =
  99                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
 100
 101         /* register our generic driver with ourselves */
 102         retval = usb_serial_register_drivers(&generic_driver, serial_drivers);
 103 #endif
 104         return retval;
 105 }
 106
 107 void usb_serial_generic_deregister(void)
 108 {
 109 #ifdef CONFIG_USB_SERIAL_GENERIC
 110         /* remove our generic driver */
 111         usb_serial_deregister_drivers(&generic_driver, serial_drivers);
 112 #endif
 113 }
 114
 115 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 116 {
 117         int result = 0;
 118         unsigned long flags;
 119
 120         dbg("%s - port %d", __func__, port->number);
 121
 122         /* clear the throttle flags */
 123         spin_lock_irqsave(&port->lock, flags);
 124         port->throttled = 0;
 125         port->throttle_req = 0;
 126         spin_unlock_irqrestore(&port->lock, flags);
 127
 128         /* if we have a bulk endpoint, start reading from it */
 129         if (port->bulk_in_size)
 130                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 131
 132         return result;
 133 }
 134 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 135
 136 static void generic_cleanup(struct usb_serial_port *port)
 137 {
 138         struct usb_serial *serial = port->serial;
 139         unsigned long flags;
 140         int i;
 141
 142         dbg("%s - port %d", __func__, port->number);
 143
 144         if (serial->dev) {
 145                 /* shutdown any bulk transfers that might be going on */
 146                 if (port->bulk_out_size) {
 147                         usb_kill_urb(port->write_urb);
 148                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 149                                 usb_kill_urb(port->write_urbs[i]);
 150
 151                         spin_lock_irqsave(&port->lock, flags);
 152                         kfifo_reset_out(&port->write_fifo);
 153                         spin_unlock_irqrestore(&port->lock, flags);
 154                 }
 155                 if (port->bulk_in_size) {
 156                         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 157                                 usb_kill_urb(port->read_urbs[i]);
 158                 }
 159         }
 160 }
 161
 162 void usb_serial_generic_close(struct usb_serial_port *port)
 163 {
 164         dbg("%s - port %d", __func__, port->number);
 165         generic_cleanup(port);
 166 }
 167 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 168
 169 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 170                                                 void *dest, size_t size)
 171 {
 172         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 173 }
 174
 175 /**
 176  * usb_serial_generic_write_start - kick off an URB write
 177  * @port:       Pointer to the &struct usb_serial_port data
 178  *
 179  * Returns zero on success, or a negative errno value
 180  */
 181 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 182 {
 183         struct urb *urb;
 184         int count, result;
 185         unsigned long flags;
 186         int i;
 187
 188         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 189                 return 0;
 190 retry:
 191         spin_lock_irqsave(&port->lock, flags);
 192         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 193                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 194                 spin_unlock_irqrestore(&port->lock, flags);
 195                 return 0;
 196         }
 197         i = (int)find_first_bit(&port->write_urbs_free,
 198                                                 ARRAY_SIZE(port->write_urbs));
 199         spin_unlock_irqrestore(&port->lock, flags);
 200
 201         urb = port->write_urbs[i];
 202         count = port->serial->type->prepare_write_buffer(port,
 203                                                 urb->transfer_buffer,
 204                                                 port->bulk_out_size);
 205         urb->transfer_buffer_length = count;
 206         usb_serial_debug_data(debug, &port->dev, __func__, count,
 207                                                 urb->transfer_buffer);
 208         spin_lock_irqsave(&port->lock, flags);
 209         port->tx_bytes += count;
 210         spin_unlock_irqrestore(&port->lock, flags);
 211
 212         clear_bit(i, &port->write_urbs_free);
 213         result = usb_submit_urb(urb, GFP_ATOMIC);
 214         if (result) {
 215                 dev_err_console(port, "%s - error submitting urb: %d\n",
 216                                                 __func__, result);
 217                 set_bit(i, &port->write_urbs_free);
 218                 spin_lock_irqsave(&port->lock, flags);
 219                 port->tx_bytes -= count;
 220                 spin_unlock_irqrestore(&port->lock, flags);
 221
 222                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 223                 return result;
 224         }
 225
 226         /* Try sending off another urb, unless in irq context (in which case
 227          * there will be no free urb). */
 228         if (!in_irq())
 229                 goto retry;
 230
 231         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 232
 233         return 0;
 234 }
 235
 236 /**
 237  * usb_serial_generic_write - generic write function for serial USB devices
 238  * @tty:        Pointer to &struct tty_struct for the device
 239  * @port:       Pointer to the &usb_serial_port structure for the device
 240  * @buf:        Pointer to the data to write
 241  * @count:      Number of bytes to write
 242  *
 243  * Returns the number of characters actually written, which may be anything
 244  * from zero to @count. If an error occurs, it returns the negative errno
 245  * value.
 246  */
 247 int usb_serial_generic_write(struct tty_struct *tty,
 248         struct usb_serial_port *port, const unsigned char *buf, int count)
 249 {
 250         int result;
 251
 252         dbg("%s - port %d", __func__, port->number);
 253
 254         /* only do something if we have a bulk out endpoint */
 255         if (!port->bulk_out_size)
 256                 return -ENODEV;
 257
 258         if (!count)
 259                 return 0;
 260
 261         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 262         result = usb_serial_generic_write_start(port);
 263         if (result)
 264                 return result;
 265
 266         return count;
 267 }
 268 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 269
 270 int usb_serial_generic_write_room(struct tty_struct *tty)
 271 {
 272         struct usb_serial_port *port = tty->driver_data;
 273         unsigned long flags;
 274         int room;
 275
 276         dbg("%s - port %d", __func__, port->number);
 277
 278         if (!port->bulk_out_size)
 279                 return 0;
 280
 281         spin_lock_irqsave(&port->lock, flags);
 282         room = kfifo_avail(&port->write_fifo);
 283         spin_unlock_irqrestore(&port->lock, flags);
 284
 285         dbg("%s - returns %d", __func__, room);
 286         return room;
 287 }
 288
 289 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 290 {
 291         struct usb_serial_port *port = tty->driver_data;
 292         unsigned long flags;
 293         int chars;
 294
 295         dbg("%s - port %d", __func__, port->number);
 296
 297         if (!port->bulk_out_size)
 298                 return 0;
 299
 300         spin_lock_irqsave(&port->lock, flags);
 301         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 302         spin_unlock_irqrestore(&port->lock, flags);
 303
 304         dbg("%s - returns %d", __func__, chars);
 305         return chars;
 306 }
 307
 308 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 309                                                 int index, gfp_t mem_flags)
 310 {
 311         int res;
 312
 313         if (!test_and_clear_bit(index, &port->read_urbs_free))
 314                 return 0;
 315
 316         dbg("%s - port %d, urb %d\n", __func__, port->number, index);
 317
 318         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 319         if (res) {
 320                 if (res != -EPERM) {
 321                         dev_err(&port->dev,
 322                                         "%s - usb_submit_urb failed: %d\n",
 323                                         __func__, res);
 324                 }
 325                 set_bit(index, &port->read_urbs_free);
 326                 return res;
 327         }
 328
 329         return 0;
 330 }
 331
 332 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 333                                         gfp_t mem_flags)
 334 {
 335         int res;
 336         int i;
 337
 338         dbg("%s - port %d", __func__, port->number);
 339
 340         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 341                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 342                 if (res)
 343                         goto err;
 344         }
 345
 346         return 0;
 347 err:
 348         for (; i >= 0; --i)
 349                 usb_kill_urb(port->read_urbs[i]);
 350
 351         return res;
 352 }
 353 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 354
 355 void usb_serial_generic_process_read_urb(struct urb *urb)
 356 {
 357         struct usb_serial_port *port = urb->context;
 358         struct tty_struct *tty;
 359         char *ch = (char *)urb->transfer_buffer;
 360         int i;
 361
 362         if (!urb->actual_length)
 363                 return;
 364
 365         tty = tty_port_tty_get(&port->port);
 366         if (!tty)
 367                 return;
 368
 369         /* The per character mucking around with sysrq path it too slow for
 370            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 371            where the USB serial is not a console anyway */
 372         if (!port->port.console || !port->sysrq)
 373                 tty_insert_flip_string(tty, ch, urb->actual_length);
 374         else {
 375                 for (i = 0; i < urb->actual_length; i++, ch++) {
 376                         if (!usb_serial_handle_sysrq_char(port, *ch))
 377                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 378                 }
 379         }
 380         tty_flip_buffer_push(tty);
 381         tty_kref_put(tty);
 382 }
 383 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 384
 385 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 386 {
 387         struct usb_serial_port *port = urb->context;
 388         unsigned char *data = urb->transfer_buffer;
 389         unsigned long flags;
 390         int i;
 391
 392         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 393                 if (urb == port->read_urbs[i])
 394                         break;
 395         }
 396         set_bit(i, &port->read_urbs_free);
 397
 398         dbg("%s - port %d, urb %d, len %d\n", __func__, port->number, i,
 399                                                         urb->actual_length);
 400         if (urb->status) {
 401                 dbg("%s - non-zero urb status: %d\n", __func__, urb->status);
 402                 return;
 403         }
 404
 405         usb_serial_debug_data(debug, &port->dev, __func__,
 406                                                 urb->actual_length, data);
 407         port->serial->type->process_read_urb(urb);
 408
 409         /* Throttle the device if requested by tty */
 410         spin_lock_irqsave(&port->lock, flags);
 411         port->throttled = port->throttle_req;
 412         if (!port->throttled) {
 413                 spin_unlock_irqrestore(&port->lock, flags);
 414                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 415         } else
 416                 spin_unlock_irqrestore(&port->lock, flags);
 417 }
 418 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 419
 420 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 421 {
 422         unsigned long flags;
 423         struct usb_serial_port *port = urb->context;
 424         int status = urb->status;
 425         int i;
 426
 427         dbg("%s - port %d", __func__, port->number);
 428
 429         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 430                 if (port->write_urbs[i] == urb)
 431                         break;
 432
 433         spin_lock_irqsave(&port->lock, flags);
 434         port->tx_bytes -= urb->transfer_buffer_length;
 435         set_bit(i, &port->write_urbs_free);
 436         spin_unlock_irqrestore(&port->lock, flags);
 437
 438         if (status) {
 439                 dbg("%s - non-zero urb status: %d", __func__, status);
 440
 441                 spin_lock_irqsave(&port->lock, flags);
 442                 kfifo_reset_out(&port->write_fifo);
 443                 spin_unlock_irqrestore(&port->lock, flags);
 444         } else {
 445                 usb_serial_generic_write_start(port);
 446         }
 447
 448         usb_serial_port_softint(port);
 449 }
 450 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 451
 452 void usb_serial_generic_throttle(struct tty_struct *tty)
 453 {
 454         struct usb_serial_port *port = tty->driver_data;
 455         unsigned long flags;
 456
 457         dbg("%s - port %d", __func__, port->number);
 458
 459         /* Set the throttle request flag. It will be picked up
 460          * by usb_serial_generic_read_bulk_callback(). */
 461         spin_lock_irqsave(&port->lock, flags);
 462         port->throttle_req = 1;
 463         spin_unlock_irqrestore(&port->lock, flags);
 464 }
 465 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 466
 467 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 468 {
 469         struct usb_serial_port *port = tty->driver_data;
 470         int was_throttled;
 471
 472         dbg("%s - port %d", __func__, port->number);
 473
 474         /* Clear the throttle flags */
 475         spin_lock_irq(&port->lock);
 476         was_throttled = port->throttled;
 477         port->throttled = port->throttle_req = 0;
 478         spin_unlock_irq(&port->lock);
 479
 480         if (was_throttled)
 481                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 482 }
 483 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 484
 485 #ifdef CONFIG_MAGIC_SYSRQ
 486 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 487 {
 488         if (port->sysrq && port->port.console) {
 489                 if (ch && time_before(jiffies, port->sysrq)) {
 490                         handle_sysrq(ch);
 491                         port->sysrq = 0;
 492                         return 1;
 493                 }
 494                 port->sysrq = 0;
 495         }
 496         return 0;
 497 }
 498 #else
 499 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 500 {
 501         return 0;
 502 }
 503 #endif
 504 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 505
 506 int usb_serial_handle_break(struct usb_serial_port *port)
 507 {
 508         if (!port->sysrq) {
 509                 port->sysrq = jiffies + HZ*5;
 510                 return 1;
 511         }
 512         port->sysrq = 0;
 513         return 0;
 514 }
 515 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 516
 517 /**
 518  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 519  *      @port: usb_serial_port structure for the open port
 520  *      @tty: tty_struct structure for the port
 521  *      @status: new carrier detect status, nonzero if active
 522  */
 523 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 524                                 struct tty_struct *tty, unsigned int status)
 525 {
 526         struct tty_port *port = &usb_port->port;
 527
 528         dbg("%s - port %d, status %d", __func__, usb_port->number, status);
 529
 530         if (status)
 531                 wake_up_interruptible(&port->open_wait);
 532         else if (tty && !C_CLOCAL(tty))
 533                 tty_hangup(tty);
 534 }
 535 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 536
 537 int usb_serial_generic_resume(struct usb_serial *serial)
 538 {
 539         struct usb_serial_port *port;
 540         int i, c = 0, r;
 541
 542         for (i = 0; i < serial->num_ports; i++) {
 543                 port = serial->port[i];
 544                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 545                         continue;
 546
 547                 if (port->bulk_in_size) {
 548                         r = usb_serial_generic_submit_read_urbs(port,
 549                                                                 GFP_NOIO);
 550                         if (r < 0)
 551                                 c++;
 552                 }
 553
 554                 if (port->bulk_out_size) {
 555                         r = usb_serial_generic_write_start(port);
 556                         if (r < 0)
 557                                 c++;
 558                 }
 559         }
 560
 561         return c ? -EIO : 0;
 562 }
 563 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 564
 565 void usb_serial_generic_disconnect(struct usb_serial *serial)
 566 {
 567         int i;
 568
 569         dbg("%s", __func__);
 570
 571         /* stop reads and writes on all ports */
 572         for (i = 0; i < serial->num_ports; ++i)
 573                 generic_cleanup(serial->port[i]);
 574 }
 575 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 576
 577 void usb_serial_generic_release(struct usb_serial *serial)
 578 {
 579         dbg("%s", __func__);
 580 }