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 __u16 vendor  = 0x05f9;
  32 static __u16 product = 0xffff;
  33
  34 module_param(vendor, ushort, 0);
  35 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  36
  37 module_param(product, ushort, 0);
  38 MODULE_PARM_DESC(product, "User specified USB idProduct");
  39
  40 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  41
  42 /* All of the device info needed for the Generic Serial Converter */
  43 struct usb_serial_driver usb_serial_generic_device = {
  44         .driver = {
  45                 .owner =        THIS_MODULE,
  46                 .name =         "generic",
  47         },
  48         .id_table =             generic_device_ids,
  49         .num_ports =            1,
  50         .disconnect =           usb_serial_generic_disconnect,
  51         .release =              usb_serial_generic_release,
  52         .throttle =             usb_serial_generic_throttle,
  53         .unthrottle =           usb_serial_generic_unthrottle,
  54         .resume =               usb_serial_generic_resume,
  55 };
  56
  57 static struct usb_serial_driver * const serial_drivers[] = {
  58         &usb_serial_generic_device, NULL
  59 };
  60
  61 #endif
  62
  63 int usb_serial_generic_register(int _debug)
  64 {
  65         int retval = 0;
  66
  67         debug = _debug;
  68 #ifdef CONFIG_USB_SERIAL_GENERIC
  69         generic_device_ids[0].idVendor = vendor;
  70         generic_device_ids[0].idProduct = product;
  71         generic_device_ids[0].match_flags =
  72                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  73
  74         /* register our generic driver with ourselves */
  75         retval = usb_serial_register_drivers(serial_drivers,
  76                         "usbserial_generic", generic_device_ids);
  77 #endif
  78         return retval;
  79 }
  80
  81 void usb_serial_generic_deregister(void)
  82 {
  83 #ifdef CONFIG_USB_SERIAL_GENERIC
  84         /* remove our generic driver */
  85         usb_serial_deregister_drivers(serial_drivers);
  86 #endif
  87 }
  88
  89 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
  90 {
  91         int result = 0;
  92         unsigned long flags;
  93
  94         /* clear the throttle flags */
  95         spin_lock_irqsave(&port->lock, flags);
  96         port->throttled = 0;
  97         port->throttle_req = 0;
  98         spin_unlock_irqrestore(&port->lock, flags);
  99
 100         /* if we have a bulk endpoint, start reading from it */
 101         if (port->bulk_in_size)
 102                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 103
 104         return result;
 105 }
 106 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 107
 108 static void generic_cleanup(struct usb_serial_port *port)
 109 {
 110         struct usb_serial *serial = port->serial;
 111         unsigned long flags;
 112         int i;
 113
 114         if (serial->dev) {
 115                 /* shutdown any bulk transfers that might be going on */
 116                 if (port->bulk_out_size) {
 117                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 118                                 usb_kill_urb(port->write_urbs[i]);
 119
 120                         spin_lock_irqsave(&port->lock, flags);
 121                         kfifo_reset_out(&port->write_fifo);
 122                         spin_unlock_irqrestore(&port->lock, flags);
 123                 }
 124                 if (port->bulk_in_size) {
 125                         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 126                                 usb_kill_urb(port->read_urbs[i]);
 127                 }
 128         }
 129 }
 130
 131 void usb_serial_generic_close(struct usb_serial_port *port)
 132 {
 133         generic_cleanup(port);
 134 }
 135 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 136
 137 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 138                                                 void *dest, size_t size)
 139 {
 140         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 141 }
 142
 143 /**
 144  * usb_serial_generic_write_start - kick off an URB write
 145  * @port:       Pointer to the &struct usb_serial_port data
 146  *
 147  * Returns zero on success, or a negative errno value
 148  */
 149 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 150 {
 151         struct urb *urb;
 152         int count, result;
 153         unsigned long flags;
 154         int i;
 155
 156         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 157                 return 0;
 158 retry:
 159         spin_lock_irqsave(&port->lock, flags);
 160         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 161                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 162                 spin_unlock_irqrestore(&port->lock, flags);
 163                 return 0;
 164         }
 165         i = (int)find_first_bit(&port->write_urbs_free,
 166                                                 ARRAY_SIZE(port->write_urbs));
 167         spin_unlock_irqrestore(&port->lock, flags);
 168
 169         urb = port->write_urbs[i];
 170         count = port->serial->type->prepare_write_buffer(port,
 171                                                 urb->transfer_buffer,
 172                                                 port->bulk_out_size);
 173         urb->transfer_buffer_length = count;
 174         usb_serial_debug_data(debug, &port->dev, __func__, count,
 175                                                 urb->transfer_buffer);
 176         spin_lock_irqsave(&port->lock, flags);
 177         port->tx_bytes += count;
 178         spin_unlock_irqrestore(&port->lock, flags);
 179
 180         clear_bit(i, &port->write_urbs_free);
 181         result = usb_submit_urb(urb, GFP_ATOMIC);
 182         if (result) {
 183                 dev_err_console(port, "%s - error submitting urb: %d\n",
 184                                                 __func__, result);
 185                 set_bit(i, &port->write_urbs_free);
 186                 spin_lock_irqsave(&port->lock, flags);
 187                 port->tx_bytes -= count;
 188                 spin_unlock_irqrestore(&port->lock, flags);
 189
 190                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 191                 return result;
 192         }
 193
 194         /* Try sending off another urb, unless in irq context (in which case
 195          * there will be no free urb). */
 196         if (!in_irq())
 197                 goto retry;
 198
 199         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 200
 201         return 0;
 202 }
 203
 204 /**
 205  * usb_serial_generic_write - generic write function for serial USB devices
 206  * @tty:        Pointer to &struct tty_struct for the device
 207  * @port:       Pointer to the &usb_serial_port structure for the device
 208  * @buf:        Pointer to the data to write
 209  * @count:      Number of bytes to write
 210  *
 211  * Returns the number of characters actually written, which may be anything
 212  * from zero to @count. If an error occurs, it returns the negative errno
 213  * value.
 214  */
 215 int usb_serial_generic_write(struct tty_struct *tty,
 216         struct usb_serial_port *port, const unsigned char *buf, int count)
 217 {
 218         int result;
 219
 220         /* only do something if we have a bulk out endpoint */
 221         if (!port->bulk_out_size)
 222                 return -ENODEV;
 223
 224         if (!count)
 225                 return 0;
 226
 227         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 228         result = usb_serial_generic_write_start(port);
 229         if (result)
 230                 return result;
 231
 232         return count;
 233 }
 234 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 235
 236 int usb_serial_generic_write_room(struct tty_struct *tty)
 237 {
 238         struct usb_serial_port *port = tty->driver_data;
 239         unsigned long flags;
 240         int room;
 241
 242         if (!port->bulk_out_size)
 243                 return 0;
 244
 245         spin_lock_irqsave(&port->lock, flags);
 246         room = kfifo_avail(&port->write_fifo);
 247         spin_unlock_irqrestore(&port->lock, flags);
 248
 249         dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
 250         return room;
 251 }
 252
 253 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 254 {
 255         struct usb_serial_port *port = tty->driver_data;
 256         unsigned long flags;
 257         int chars;
 258
 259         if (!port->bulk_out_size)
 260                 return 0;
 261
 262         spin_lock_irqsave(&port->lock, flags);
 263         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 264         spin_unlock_irqrestore(&port->lock, flags);
 265
 266         dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
 267         return chars;
 268 }
 269
 270 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 271                                                 int index, gfp_t mem_flags)
 272 {
 273         int res;
 274
 275         if (!test_and_clear_bit(index, &port->read_urbs_free))
 276                 return 0;
 277
 278         dev_dbg(&port->dev, "%s - port %d, urb %d\n", __func__,
 279                 port->number, index);
 280
 281         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 282         if (res) {
 283                 if (res != -EPERM) {
 284                         dev_err(&port->dev,
 285                                         "%s - usb_submit_urb failed: %d\n",
 286                                         __func__, res);
 287                 }
 288                 set_bit(index, &port->read_urbs_free);
 289                 return res;
 290         }
 291
 292         return 0;
 293 }
 294
 295 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 296                                         gfp_t mem_flags)
 297 {
 298         int res;
 299         int i;
 300
 301         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 302                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 303                 if (res)
 304                         goto err;
 305         }
 306
 307         return 0;
 308 err:
 309         for (; i >= 0; --i)
 310                 usb_kill_urb(port->read_urbs[i]);
 311
 312         return res;
 313 }
 314 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 315
 316 void usb_serial_generic_process_read_urb(struct urb *urb)
 317 {
 318         struct usb_serial_port *port = urb->context;
 319         struct tty_struct *tty;
 320         char *ch = (char *)urb->transfer_buffer;
 321         int i;
 322
 323         if (!urb->actual_length)
 324                 return;
 325
 326         tty = tty_port_tty_get(&port->port);
 327         if (!tty)
 328                 return;
 329
 330         /* The per character mucking around with sysrq path it too slow for
 331            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 332            where the USB serial is not a console anyway */
 333         if (!port->port.console || !port->sysrq)
 334                 tty_insert_flip_string(tty, ch, urb->actual_length);
 335         else {
 336                 for (i = 0; i < urb->actual_length; i++, ch++) {
 337                         if (!usb_serial_handle_sysrq_char(port, *ch))
 338                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 339                 }
 340         }
 341         tty_flip_buffer_push(tty);
 342         tty_kref_put(tty);
 343 }
 344 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 345
 346 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 347 {
 348         struct usb_serial_port *port = urb->context;
 349         unsigned char *data = urb->transfer_buffer;
 350         unsigned long flags;
 351         int i;
 352
 353         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 354                 if (urb == port->read_urbs[i])
 355                         break;
 356         }
 357         set_bit(i, &port->read_urbs_free);
 358
 359         dev_dbg(&port->dev, "%s - port %d, urb %d, len %d\n",
 360                 __func__, port->number, i, urb->actual_length);
 361
 362         if (urb->status) {
 363                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 364                         __func__, urb->status);
 365                 return;
 366         }
 367
 368         usb_serial_debug_data(debug, &port->dev, __func__,
 369                                                 urb->actual_length, data);
 370         port->serial->type->process_read_urb(urb);
 371
 372         /* Throttle the device if requested by tty */
 373         spin_lock_irqsave(&port->lock, flags);
 374         port->throttled = port->throttle_req;
 375         if (!port->throttled) {
 376                 spin_unlock_irqrestore(&port->lock, flags);
 377                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 378         } else
 379                 spin_unlock_irqrestore(&port->lock, flags);
 380 }
 381 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 382
 383 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 384 {
 385         unsigned long flags;
 386         struct usb_serial_port *port = urb->context;
 387         int status = urb->status;
 388         int i;
 389
 390         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 391                 if (port->write_urbs[i] == urb)
 392                         break;
 393
 394         spin_lock_irqsave(&port->lock, flags);
 395         port->tx_bytes -= urb->transfer_buffer_length;
 396         set_bit(i, &port->write_urbs_free);
 397         spin_unlock_irqrestore(&port->lock, flags);
 398
 399         if (status) {
 400                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 401                         __func__, status);
 402
 403                 spin_lock_irqsave(&port->lock, flags);
 404                 kfifo_reset_out(&port->write_fifo);
 405                 spin_unlock_irqrestore(&port->lock, flags);
 406         } else {
 407                 usb_serial_generic_write_start(port);
 408         }
 409
 410         usb_serial_port_softint(port);
 411 }
 412 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 413
 414 void usb_serial_generic_throttle(struct tty_struct *tty)
 415 {
 416         struct usb_serial_port *port = tty->driver_data;
 417         unsigned long flags;
 418
 419         /* Set the throttle request flag. It will be picked up
 420          * by usb_serial_generic_read_bulk_callback(). */
 421         spin_lock_irqsave(&port->lock, flags);
 422         port->throttle_req = 1;
 423         spin_unlock_irqrestore(&port->lock, flags);
 424 }
 425 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 426
 427 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 428 {
 429         struct usb_serial_port *port = tty->driver_data;
 430         int was_throttled;
 431
 432         /* Clear the throttle flags */
 433         spin_lock_irq(&port->lock);
 434         was_throttled = port->throttled;
 435         port->throttled = port->throttle_req = 0;
 436         spin_unlock_irq(&port->lock);
 437
 438         if (was_throttled)
 439                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 440 }
 441 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 442
 443 #ifdef CONFIG_MAGIC_SYSRQ
 444 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 445 {
 446         if (port->sysrq && port->port.console) {
 447                 if (ch && time_before(jiffies, port->sysrq)) {
 448                         handle_sysrq(ch);
 449                         port->sysrq = 0;
 450                         return 1;
 451                 }
 452                 port->sysrq = 0;
 453         }
 454         return 0;
 455 }
 456 #else
 457 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 458 {
 459         return 0;
 460 }
 461 #endif
 462 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 463
 464 int usb_serial_handle_break(struct usb_serial_port *port)
 465 {
 466         if (!port->sysrq) {
 467                 port->sysrq = jiffies + HZ*5;
 468                 return 1;
 469         }
 470         port->sysrq = 0;
 471         return 0;
 472 }
 473 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 474
 475 /**
 476  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 477  *      @port: usb_serial_port structure for the open port
 478  *      @tty: tty_struct structure for the port
 479  *      @status: new carrier detect status, nonzero if active
 480  */
 481 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 482                                 struct tty_struct *tty, unsigned int status)
 483 {
 484         struct tty_port *port = &usb_port->port;
 485
 486         dev_dbg(&usb_port->dev, "%s - port %d, status %d\n", __func__,
 487                 usb_port->number, status);
 488
 489         if (status)
 490                 wake_up_interruptible(&port->open_wait);
 491         else if (tty && !C_CLOCAL(tty))
 492                 tty_hangup(tty);
 493 }
 494 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 495
 496 int usb_serial_generic_resume(struct usb_serial *serial)
 497 {
 498         struct usb_serial_port *port;
 499         int i, c = 0, r;
 500
 501         for (i = 0; i < serial->num_ports; i++) {
 502                 port = serial->port[i];
 503                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 504                         continue;
 505
 506                 if (port->bulk_in_size) {
 507                         r = usb_serial_generic_submit_read_urbs(port,
 508                                                                 GFP_NOIO);
 509                         if (r < 0)
 510                                 c++;
 511                 }
 512
 513                 if (port->bulk_out_size) {
 514                         r = usb_serial_generic_write_start(port);
 515                         if (r < 0)
 516                                 c++;
 517                 }
 518         }
 519
 520         return c ? -EIO : 0;
 521 }
 522 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 523
 524 void usb_serial_generic_disconnect(struct usb_serial *serial)
 525 {
 526         int i;
 527
 528         /* stop reads and writes on all ports */
 529         for (i = 0; i < serial->num_ports; ++i)
 530                 generic_cleanup(serial->port[i]);
 531 }
 532 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 533
 534 void usb_serial_generic_release(struct usb_serial *serial)
 535 {
 536 }