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