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         .id_table =     generic_serial_ids,
  56 };
  57
  58 /* All of the device info needed for the Generic Serial Converter */
  59 struct usb_serial_driver usb_serial_generic_device = {
  60         .driver = {
  61                 .owner =        THIS_MODULE,
  62                 .name =         "generic",
  63         },
  64         .id_table =             generic_device_ids,
  65         .num_ports =            1,
  66         .disconnect =           usb_serial_generic_disconnect,
  67         .release =              usb_serial_generic_release,
  68         .throttle =             usb_serial_generic_throttle,
  69         .unthrottle =           usb_serial_generic_unthrottle,
  70         .resume =               usb_serial_generic_resume,
  71 };
  72
  73 static struct usb_serial_driver * const serial_drivers[] = {
  74         &usb_serial_generic_device, NULL
  75 };
  76
  77 static int generic_probe(struct usb_interface *interface,
  78                                const struct usb_device_id *id)
  79 {
  80         const struct usb_device_id *id_pattern;
  81
  82         id_pattern = usb_match_id(interface, generic_device_ids);
  83         if (id_pattern != NULL)
  84                 return usb_serial_probe(interface, id);
  85         return -ENODEV;
  86 }
  87 #endif
  88
  89 int usb_serial_generic_register(int _debug)
  90 {
  91         int retval = 0;
  92
  93         debug = _debug;
  94 #ifdef CONFIG_USB_SERIAL_GENERIC
  95         generic_device_ids[0].idVendor = vendor;
  96         generic_device_ids[0].idProduct = product;
  97         generic_device_ids[0].match_flags =
  98                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  99
 100         /* register our generic driver with ourselves */
 101         retval = usb_serial_register_drivers(&generic_driver, serial_drivers);
 102 #endif
 103         return retval;
 104 }
 105
 106 void usb_serial_generic_deregister(void)
 107 {
 108 #ifdef CONFIG_USB_SERIAL_GENERIC
 109         /* remove our generic driver */
 110         usb_serial_deregister_drivers(&generic_driver, serial_drivers);
 111 #endif
 112 }
 113
 114 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
 115 {
 116         int result = 0;
 117         unsigned long flags;
 118
 119         /* clear the throttle flags */
 120         spin_lock_irqsave(&port->lock, flags);
 121         port->throttled = 0;
 122         port->throttle_req = 0;
 123         spin_unlock_irqrestore(&port->lock, flags);
 124
 125         /* if we have a bulk endpoint, start reading from it */
 126         if (port->bulk_in_size)
 127                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 128
 129         return result;
 130 }
 131 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 132
 133 static void generic_cleanup(struct usb_serial_port *port)
 134 {
 135         struct usb_serial *serial = port->serial;
 136         unsigned long flags;
 137         int i;
 138
 139         if (serial->dev) {
 140                 /* shutdown any bulk transfers that might be going on */
 141                 if (port->bulk_out_size) {
 142                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 143                                 usb_kill_urb(port->write_urbs[i]);
 144
 145                         spin_lock_irqsave(&port->lock, flags);
 146                         kfifo_reset_out(&port->write_fifo);
 147                         spin_unlock_irqrestore(&port->lock, flags);
 148                 }
 149                 if (port->bulk_in_size) {
 150                         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 151                                 usb_kill_urb(port->read_urbs[i]);
 152                 }
 153         }
 154 }
 155
 156 void usb_serial_generic_close(struct usb_serial_port *port)
 157 {
 158         generic_cleanup(port);
 159 }
 160 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 161
 162 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 163                                                 void *dest, size_t size)
 164 {
 165         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 166 }
 167
 168 /**
 169  * usb_serial_generic_write_start - kick off an URB write
 170  * @port:       Pointer to the &struct usb_serial_port data
 171  *
 172  * Returns zero on success, or a negative errno value
 173  */
 174 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 175 {
 176         struct urb *urb;
 177         int count, result;
 178         unsigned long flags;
 179         int i;
 180
 181         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 182                 return 0;
 183 retry:
 184         spin_lock_irqsave(&port->lock, flags);
 185         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 186                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 187                 spin_unlock_irqrestore(&port->lock, flags);
 188                 return 0;
 189         }
 190         i = (int)find_first_bit(&port->write_urbs_free,
 191                                                 ARRAY_SIZE(port->write_urbs));
 192         spin_unlock_irqrestore(&port->lock, flags);
 193
 194         urb = port->write_urbs[i];
 195         count = port->serial->type->prepare_write_buffer(port,
 196                                                 urb->transfer_buffer,
 197                                                 port->bulk_out_size);
 198         urb->transfer_buffer_length = count;
 199         usb_serial_debug_data(debug, &port->dev, __func__, count,
 200                                                 urb->transfer_buffer);
 201         spin_lock_irqsave(&port->lock, flags);
 202         port->tx_bytes += count;
 203         spin_unlock_irqrestore(&port->lock, flags);
 204
 205         clear_bit(i, &port->write_urbs_free);
 206         result = usb_submit_urb(urb, GFP_ATOMIC);
 207         if (result) {
 208                 dev_err_console(port, "%s - error submitting urb: %d\n",
 209                                                 __func__, result);
 210                 set_bit(i, &port->write_urbs_free);
 211                 spin_lock_irqsave(&port->lock, flags);
 212                 port->tx_bytes -= count;
 213                 spin_unlock_irqrestore(&port->lock, flags);
 214
 215                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 216                 return result;
 217         }
 218
 219         /* Try sending off another urb, unless in irq context (in which case
 220          * there will be no free urb). */
 221         if (!in_irq())
 222                 goto retry;
 223
 224         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 225
 226         return 0;
 227 }
 228
 229 /**
 230  * usb_serial_generic_write - generic write function for serial USB devices
 231  * @tty:        Pointer to &struct tty_struct for the device
 232  * @port:       Pointer to the &usb_serial_port structure for the device
 233  * @buf:        Pointer to the data to write
 234  * @count:      Number of bytes to write
 235  *
 236  * Returns the number of characters actually written, which may be anything
 237  * from zero to @count. If an error occurs, it returns the negative errno
 238  * value.
 239  */
 240 int usb_serial_generic_write(struct tty_struct *tty,
 241         struct usb_serial_port *port, const unsigned char *buf, int count)
 242 {
 243         int result;
 244
 245         /* only do something if we have a bulk out endpoint */
 246         if (!port->bulk_out_size)
 247                 return -ENODEV;
 248
 249         if (!count)
 250                 return 0;
 251
 252         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 253         result = usb_serial_generic_write_start(port);
 254         if (result)
 255                 return result;
 256
 257         return count;
 258 }
 259 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 260
 261 int usb_serial_generic_write_room(struct tty_struct *tty)
 262 {
 263         struct usb_serial_port *port = tty->driver_data;
 264         unsigned long flags;
 265         int room;
 266
 267         if (!port->bulk_out_size)
 268                 return 0;
 269
 270         spin_lock_irqsave(&port->lock, flags);
 271         room = kfifo_avail(&port->write_fifo);
 272         spin_unlock_irqrestore(&port->lock, flags);
 273
 274         dbg("%s - returns %d", __func__, room);
 275         return room;
 276 }
 277
 278 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 279 {
 280         struct usb_serial_port *port = tty->driver_data;
 281         unsigned long flags;
 282         int chars;
 283
 284         if (!port->bulk_out_size)
 285                 return 0;
 286
 287         spin_lock_irqsave(&port->lock, flags);
 288         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 289         spin_unlock_irqrestore(&port->lock, flags);
 290
 291         dbg("%s - returns %d", __func__, chars);
 292         return chars;
 293 }
 294
 295 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 296                                                 int index, gfp_t mem_flags)
 297 {
 298         int res;
 299
 300         if (!test_and_clear_bit(index, &port->read_urbs_free))
 301                 return 0;
 302
 303         dbg("%s - port %d, urb %d", __func__, port->number, index);
 304
 305         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 306         if (res) {
 307                 if (res != -EPERM) {
 308                         dev_err(&port->dev,
 309                                         "%s - usb_submit_urb failed: %d\n",
 310                                         __func__, res);
 311                 }
 312                 set_bit(index, &port->read_urbs_free);
 313                 return res;
 314         }
 315
 316         return 0;
 317 }
 318
 319 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 320                                         gfp_t mem_flags)
 321 {
 322         int res;
 323         int i;
 324
 325         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 326                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 327                 if (res)
 328                         goto err;
 329         }
 330
 331         return 0;
 332 err:
 333         for (; i >= 0; --i)
 334                 usb_kill_urb(port->read_urbs[i]);
 335
 336         return res;
 337 }
 338 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 339
 340 void usb_serial_generic_process_read_urb(struct urb *urb)
 341 {
 342         struct usb_serial_port *port = urb->context;
 343         struct tty_struct *tty;
 344         char *ch = (char *)urb->transfer_buffer;
 345         int i;
 346
 347         if (!urb->actual_length)
 348                 return;
 349
 350         tty = tty_port_tty_get(&port->port);
 351         if (!tty)
 352                 return;
 353
 354         /* The per character mucking around with sysrq path it too slow for
 355            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 356            where the USB serial is not a console anyway */
 357         if (!port->port.console || !port->sysrq)
 358                 tty_insert_flip_string(tty, ch, urb->actual_length);
 359         else {
 360                 for (i = 0; i < urb->actual_length; i++, ch++) {
 361                         if (!usb_serial_handle_sysrq_char(port, *ch))
 362                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 363                 }
 364         }
 365         tty_flip_buffer_push(tty);
 366         tty_kref_put(tty);
 367 }
 368 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 369
 370 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 371 {
 372         struct usb_serial_port *port = urb->context;
 373         unsigned char *data = urb->transfer_buffer;
 374         unsigned long flags;
 375         int i;
 376
 377         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 378                 if (urb == port->read_urbs[i])
 379                         break;
 380         }
 381         set_bit(i, &port->read_urbs_free);
 382
 383         dbg("%s - port %d, urb %d, len %d", __func__, port->number, i,
 384                                                         urb->actual_length);
 385         if (urb->status) {
 386                 dbg("%s - non-zero urb status: %d", __func__, urb->status);
 387                 return;
 388         }
 389
 390         usb_serial_debug_data(debug, &port->dev, __func__,
 391                                                 urb->actual_length, data);
 392         port->serial->type->process_read_urb(urb);
 393
 394         /* Throttle the device if requested by tty */
 395         spin_lock_irqsave(&port->lock, flags);
 396         port->throttled = port->throttle_req;
 397         if (!port->throttled) {
 398                 spin_unlock_irqrestore(&port->lock, flags);
 399                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 400         } else
 401                 spin_unlock_irqrestore(&port->lock, flags);
 402 }
 403 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 404
 405 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 406 {
 407         unsigned long flags;
 408         struct usb_serial_port *port = urb->context;
 409         int status = urb->status;
 410         int i;
 411
 412         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 413                 if (port->write_urbs[i] == urb)
 414                         break;
 415
 416         spin_lock_irqsave(&port->lock, flags);
 417         port->tx_bytes -= urb->transfer_buffer_length;
 418         set_bit(i, &port->write_urbs_free);
 419         spin_unlock_irqrestore(&port->lock, flags);
 420
 421         if (status) {
 422                 dbg("%s - non-zero urb status: %d", __func__, status);
 423
 424                 spin_lock_irqsave(&port->lock, flags);
 425                 kfifo_reset_out(&port->write_fifo);
 426                 spin_unlock_irqrestore(&port->lock, flags);
 427         } else {
 428                 usb_serial_generic_write_start(port);
 429         }
 430
 431         usb_serial_port_softint(port);
 432 }
 433 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 434
 435 void usb_serial_generic_throttle(struct tty_struct *tty)
 436 {
 437         struct usb_serial_port *port = tty->driver_data;
 438         unsigned long flags;
 439
 440         /* Set the throttle request flag. It will be picked up
 441          * by usb_serial_generic_read_bulk_callback(). */
 442         spin_lock_irqsave(&port->lock, flags);
 443         port->throttle_req = 1;
 444         spin_unlock_irqrestore(&port->lock, flags);
 445 }
 446 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 447
 448 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 449 {
 450         struct usb_serial_port *port = tty->driver_data;
 451         int was_throttled;
 452
 453         /* Clear the throttle flags */
 454         spin_lock_irq(&port->lock);
 455         was_throttled = port->throttled;
 456         port->throttled = port->throttle_req = 0;
 457         spin_unlock_irq(&port->lock);
 458
 459         if (was_throttled)
 460                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 461 }
 462 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 463
 464 #ifdef CONFIG_MAGIC_SYSRQ
 465 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 466 {
 467         if (port->sysrq && port->port.console) {
 468                 if (ch && time_before(jiffies, port->sysrq)) {
 469                         handle_sysrq(ch);
 470                         port->sysrq = 0;
 471                         return 1;
 472                 }
 473                 port->sysrq = 0;
 474         }
 475         return 0;
 476 }
 477 #else
 478 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 479 {
 480         return 0;
 481 }
 482 #endif
 483 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 484
 485 int usb_serial_handle_break(struct usb_serial_port *port)
 486 {
 487         if (!port->sysrq) {
 488                 port->sysrq = jiffies + HZ*5;
 489                 return 1;
 490         }
 491         port->sysrq = 0;
 492         return 0;
 493 }
 494 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 495
 496 /**
 497  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 498  *      @port: usb_serial_port structure for the open port
 499  *      @tty: tty_struct structure for the port
 500  *      @status: new carrier detect status, nonzero if active
 501  */
 502 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 503                                 struct tty_struct *tty, unsigned int status)
 504 {
 505         struct tty_port *port = &usb_port->port;
 506
 507         dbg("%s - port %d, status %d", __func__, usb_port->number, status);
 508
 509         if (status)
 510                 wake_up_interruptible(&port->open_wait);
 511         else if (tty && !C_CLOCAL(tty))
 512                 tty_hangup(tty);
 513 }
 514 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 515
 516 int usb_serial_generic_resume(struct usb_serial *serial)
 517 {
 518         struct usb_serial_port *port;
 519         int i, c = 0, r;
 520
 521         for (i = 0; i < serial->num_ports; i++) {
 522                 port = serial->port[i];
 523                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 524                         continue;
 525
 526                 if (port->bulk_in_size) {
 527                         r = usb_serial_generic_submit_read_urbs(port,
 528                                                                 GFP_NOIO);
 529                         if (r < 0)
 530                                 c++;
 531                 }
 532
 533                 if (port->bulk_out_size) {
 534                         r = usb_serial_generic_write_start(port);
 535                         if (r < 0)
 536                                 c++;
 537                 }
 538         }
 539
 540         return c ? -EIO : 0;
 541 }
 542 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 543
 544 void usb_serial_generic_disconnect(struct usb_serial *serial)
 545 {
 546         int i;
 547
 548         /* stop reads and writes on all ports */
 549         for (i = 0; i < serial->num_ports; ++i)
 550                 generic_cleanup(serial->port[i]);
 551 }
 552 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 553
 554 void usb_serial_generic_release(struct usb_serial *serial)
 555 {
 556 }