drivers/usb/serial/generic.c

   1 /*
   2  * USB Serial Converter Generic functions
   3  *
   4  * Copyright (C) 2010 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_urb(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                         usb_kill_urb(port->read_urb);
 162         }
 163 }
 164
 165 void usb_serial_generic_close(struct usb_serial_port *port)
 166 {
 167         dbg("%s - port %d", __func__, port->number);
 168         generic_cleanup(port);
 169 }
 170 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 171
 172 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 173                                                 void *dest, size_t size)
 174 {
 175         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 176 }
 177
 178 /**
 179  * usb_serial_generic_write_start - kick off an URB write
 180  * @port:       Pointer to the &struct usb_serial_port data
 181  *
 182  * Returns zero on success, or a negative errno value
 183  */
 184 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 185 {
 186         struct urb *urb;
 187         int count, result;
 188         unsigned long flags;
 189         int i;
 190
 191         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 192                 return 0;
 193 retry:
 194         spin_lock_irqsave(&port->lock, flags);
 195         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 196                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 197                 spin_unlock_irqrestore(&port->lock, flags);
 198                 return 0;
 199         }
 200         i = (int)find_first_bit(&port->write_urbs_free,
 201                                                 ARRAY_SIZE(port->write_urbs));
 202         spin_unlock_irqrestore(&port->lock, flags);
 203
 204         urb = port->write_urbs[i];
 205         count = port->serial->type->prepare_write_buffer(port,
 206                                                 urb->transfer_buffer,
 207                                                 port->bulk_out_size);
 208         urb->transfer_buffer_length = count;
 209         usb_serial_debug_data(debug, &port->dev, __func__, count,
 210                                                 urb->transfer_buffer);
 211         spin_lock_irqsave(&port->lock, flags);
 212         port->tx_bytes += count;
 213         spin_unlock_irqrestore(&port->lock, flags);
 214
 215         clear_bit(i, &port->write_urbs_free);
 216         result = usb_submit_urb(urb, GFP_ATOMIC);
 217         if (result) {
 218                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
 219                                                 __func__, result);
 220                 set_bit(i, &port->write_urbs_free);
 221                 spin_lock_irqsave(&port->lock, flags);
 222                 port->tx_bytes -= count;
 223                 spin_unlock_irqrestore(&port->lock, flags);
 224
 225                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 226                 return result;
 227         }
 228
 229         /* Try sending off another urb, unless in irq context (in which case
 230          * there will be no free urb). */
 231         if (!in_irq())
 232                 goto retry;
 233
 234         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 235
 236         return 0;
 237 }
 238
 239 /**
 240  * usb_serial_generic_write - generic write function for serial USB devices
 241  * @tty:        Pointer to &struct tty_struct for the device
 242  * @port:       Pointer to the &usb_serial_port structure for the device
 243  * @buf:        Pointer to the data to write
 244  * @count:      Number of bytes to write
 245  *
 246  * Returns the number of characters actually written, which may be anything
 247  * from zero to @count. If an error occurs, it returns the negative errno
 248  * value.
 249  */
 250 int usb_serial_generic_write(struct tty_struct *tty,
 251         struct usb_serial_port *port, const unsigned char *buf, int count)
 252 {
 253         int result;
 254
 255         dbg("%s - port %d", __func__, port->number);
 256
 257         /* only do something if we have a bulk out endpoint */
 258         if (!port->bulk_out_size)
 259                 return -ENODEV;
 260
 261         if (!count)
 262                 return 0;
 263
 264         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 265         result = usb_serial_generic_write_start(port);
 266         if (result)
 267                 return result;
 268
 269         return count;
 270 }
 271 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 272
 273 int usb_serial_generic_write_room(struct tty_struct *tty)
 274 {
 275         struct usb_serial_port *port = tty->driver_data;
 276         unsigned long flags;
 277         int room;
 278
 279         dbg("%s - port %d", __func__, port->number);
 280
 281         if (!port->bulk_out_size)
 282                 return 0;
 283
 284         spin_lock_irqsave(&port->lock, flags);
 285         room = kfifo_avail(&port->write_fifo);
 286         spin_unlock_irqrestore(&port->lock, flags);
 287
 288         dbg("%s - returns %d", __func__, room);
 289         return room;
 290 }
 291
 292 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 293 {
 294         struct usb_serial_port *port = tty->driver_data;
 295         unsigned long flags;
 296         int chars;
 297
 298         dbg("%s - port %d", __func__, port->number);
 299
 300         if (!port->bulk_out_size)
 301                 return 0;
 302
 303         spin_lock_irqsave(&port->lock, flags);
 304         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 305         spin_unlock_irqrestore(&port->lock, flags);
 306
 307         dbg("%s - returns %d", __func__, chars);
 308         return chars;
 309 }
 310
 311 int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 312                                         gfp_t mem_flags)
 313 {
 314         int result;
 315
 316         result = usb_submit_urb(port->read_urb, mem_flags);
 317         if (result && result != -EPERM) {
 318                 dev_err(&port->dev, "%s - error submitting urb: %d\n",
 319                                                         __func__, result);
 320         }
 321         return result;
 322 }
 323 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urb);
 324
 325 void usb_serial_generic_process_read_urb(struct urb *urb)
 326 {
 327         struct usb_serial_port *port = urb->context;
 328         struct tty_struct *tty;
 329         char *ch = (char *)urb->transfer_buffer;
 330         int i;
 331
 332         if (!urb->actual_length)
 333                 return;
 334
 335         tty = tty_port_tty_get(&port->port);
 336         if (!tty)
 337                 return;
 338
 339         /* The per character mucking around with sysrq path it too slow for
 340            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 341            where the USB serial is not a console anyway */
 342         if (!port->port.console || !port->sysrq)
 343                 tty_insert_flip_string(tty, ch, urb->actual_length);
 344         else {
 345                 for (i = 0; i < urb->actual_length; i++, ch++) {
 346                         if (!usb_serial_handle_sysrq_char(port, *ch))
 347                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 348                 }
 349         }
 350         tty_flip_buffer_push(tty);
 351         tty_kref_put(tty);
 352 }
 353 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 354
 355 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 356 {
 357         struct usb_serial_port *port = urb->context;
 358         unsigned char *data = urb->transfer_buffer;
 359         int status = urb->status;
 360         unsigned long flags;
 361
 362         dbg("%s - port %d", __func__, port->number);
 363
 364         if (unlikely(status != 0)) {
 365                 dbg("%s - nonzero read bulk status received: %d",
 366                     __func__, status);
 367                 return;
 368         }
 369
 370         usb_serial_debug_data(debug, &port->dev, __func__,
 371                                                 urb->actual_length, data);
 372         port->serial->type->process_read_urb(urb);
 373
 374         /* Throttle the device if requested by tty */
 375         spin_lock_irqsave(&port->lock, flags);
 376         port->throttled = port->throttle_req;
 377         if (!port->throttled) {
 378                 spin_unlock_irqrestore(&port->lock, flags);
 379                 usb_serial_generic_submit_read_urb(port, GFP_ATOMIC);
 380         } else
 381                 spin_unlock_irqrestore(&port->lock, flags);
 382 }
 383 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 384
 385 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 386 {
 387         unsigned long flags;
 388         struct usb_serial_port *port = urb->context;
 389         int status = urb->status;
 390         int i;
 391
 392         dbg("%s - port %d", __func__, port->number);
 393
 394         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 395                 if (port->write_urbs[i] == urb)
 396                         break;
 397
 398         spin_lock_irqsave(&port->lock, flags);
 399         port->tx_bytes -= urb->transfer_buffer_length;
 400         set_bit(i, &port->write_urbs_free);
 401         spin_unlock_irqrestore(&port->lock, flags);
 402
 403         if (status) {
 404                 dbg("%s - non-zero urb status: %d", __func__, status);
 405
 406                 spin_lock_irqsave(&port->lock, flags);
 407                 kfifo_reset_out(&port->write_fifo);
 408                 spin_unlock_irqrestore(&port->lock, flags);
 409         } else {
 410                 usb_serial_generic_write_start(port);
 411         }
 412
 413         usb_serial_port_softint(port);
 414 }
 415 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 416
 417 void usb_serial_generic_throttle(struct tty_struct *tty)
 418 {
 419         struct usb_serial_port *port = tty->driver_data;
 420         unsigned long flags;
 421
 422         dbg("%s - port %d", __func__, port->number);
 423
 424         /* Set the throttle request flag. It will be picked up
 425          * by usb_serial_generic_read_bulk_callback(). */
 426         spin_lock_irqsave(&port->lock, flags);
 427         port->throttle_req = 1;
 428         spin_unlock_irqrestore(&port->lock, flags);
 429 }
 430 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 431
 432 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 433 {
 434         struct usb_serial_port *port = tty->driver_data;
 435         int was_throttled;
 436
 437         dbg("%s - port %d", __func__, port->number);
 438
 439         /* Clear the throttle flags */
 440         spin_lock_irq(&port->lock);
 441         was_throttled = port->throttled;
 442         port->throttled = port->throttle_req = 0;
 443         spin_unlock_irq(&port->lock);
 444
 445         if (was_throttled)
 446                 usb_serial_generic_submit_read_urb(port, GFP_KERNEL);
 447 }
 448 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 449
 450 #ifdef CONFIG_MAGIC_SYSRQ
 451 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 452 {
 453         if (port->sysrq && port->port.console) {
 454                 if (ch && time_before(jiffies, port->sysrq)) {
 455                         handle_sysrq(ch);
 456                         port->sysrq = 0;
 457                         return 1;
 458                 }
 459                 port->sysrq = 0;
 460         }
 461         return 0;
 462 }
 463 #else
 464 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 465 {
 466         return 0;
 467 }
 468 #endif
 469 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 470
 471 int usb_serial_handle_break(struct usb_serial_port *port)
 472 {
 473         if (!port->sysrq) {
 474                 port->sysrq = jiffies + HZ*5;
 475                 return 1;
 476         }
 477         port->sysrq = 0;
 478         return 0;
 479 }
 480 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 481
 482 /**
 483  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 484  *      @port: usb_serial_port structure for the open port
 485  *      @tty: tty_struct structure for the port
 486  *      @status: new carrier detect status, nonzero if active
 487  */
 488 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 489                                 struct tty_struct *tty, unsigned int status)
 490 {
 491         struct tty_port *port = &usb_port->port;
 492
 493         dbg("%s - port %d, status %d", __func__, usb_port->number, status);
 494
 495         if (status)
 496                 wake_up_interruptible(&port->open_wait);
 497         else if (tty && !C_CLOCAL(tty))
 498                 tty_hangup(tty);
 499 }
 500 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 501
 502 int usb_serial_generic_resume(struct usb_serial *serial)
 503 {
 504         struct usb_serial_port *port;
 505         int i, c = 0, r;
 506
 507         for (i = 0; i < serial->num_ports; i++) {
 508                 port = serial->port[i];
 509                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 510                         continue;
 511
 512                 if (port->read_urb) {
 513                         r = usb_submit_urb(port->read_urb, GFP_NOIO);
 514                         if (r < 0)
 515                                 c++;
 516                 }
 517
 518                 if (port->bulk_out_size) {
 519                         r = usb_serial_generic_write_start(port);
 520                         if (r < 0)
 521                                 c++;
 522                 }
 523         }
 524
 525         return c ? -EIO : 0;
 526 }
 527 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 528
 529 void usb_serial_generic_disconnect(struct usb_serial *serial)
 530 {
 531         int i;
 532
 533         dbg("%s", __func__);
 534
 535         /* stop reads and writes on all ports */
 536         for (i = 0; i < serial->num_ports; ++i)
 537                 generic_cleanup(serial->port[i]);
 538 }
 539 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 540
 541 void usb_serial_generic_release(struct usb_serial *serial)
 542 {
 543         dbg("%s", __func__);
 544 }