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 #ifdef CONFIG_USB_SERIAL_GENERIC
  28
  29 static __u16 vendor  = 0x05f9;
  30 static __u16 product = 0xffff;
  31
  32 module_param(vendor, ushort, 0);
  33 MODULE_PARM_DESC(vendor, "User specified USB idVendor");
  34
  35 module_param(product, ushort, 0);
  36 MODULE_PARM_DESC(product, "User specified USB idProduct");
  37
  38 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
  39
  40 /* All of the device info needed for the Generic Serial Converter */
  41 struct usb_serial_driver usb_serial_generic_device = {
  42         .driver = {
  43                 .owner =        THIS_MODULE,
  44                 .name =         "generic",
  45         },
  46         .id_table =             generic_device_ids,
  47         .num_ports =            1,
  48         .disconnect =           usb_serial_generic_disconnect,
  49         .release =              usb_serial_generic_release,
  50         .throttle =             usb_serial_generic_throttle,
  51         .unthrottle =           usb_serial_generic_unthrottle,
  52         .resume =               usb_serial_generic_resume,
  53 };
  54
  55 static struct usb_serial_driver * const serial_drivers[] = {
  56         &usb_serial_generic_device, NULL
  57 };
  58
  59 #endif
  60
  61 int usb_serial_generic_register(void)
  62 {
  63         int retval = 0;
  64
  65 #ifdef CONFIG_USB_SERIAL_GENERIC
  66         generic_device_ids[0].idVendor = vendor;
  67         generic_device_ids[0].idProduct = product;
  68         generic_device_ids[0].match_flags =
  69                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  70
  71         /* register our generic driver with ourselves */
  72         retval = usb_serial_register_drivers(serial_drivers,
  73                         "usbserial_generic", generic_device_ids);
  74 #endif
  75         return retval;
  76 }
  77
  78 void usb_serial_generic_deregister(void)
  79 {
  80 #ifdef CONFIG_USB_SERIAL_GENERIC
  81         /* remove our generic driver */
  82         usb_serial_deregister_drivers(serial_drivers);
  83 #endif
  84 }
  85
  86 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
  87 {
  88         int result = 0;
  89         unsigned long flags;
  90
  91         /* clear the throttle flags */
  92         spin_lock_irqsave(&port->lock, flags);
  93         port->throttled = 0;
  94         port->throttle_req = 0;
  95         spin_unlock_irqrestore(&port->lock, flags);
  96
  97         /* if we have a bulk endpoint, start reading from it */
  98         if (port->bulk_in_size)
  99                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 100
 101         return result;
 102 }
 103 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
 104
 105 static void generic_cleanup(struct usb_serial_port *port)
 106 {
 107         struct usb_serial *serial = port->serial;
 108         unsigned long flags;
 109         int i;
 110
 111         if (serial->dev) {
 112                 /* shutdown any bulk transfers that might be going on */
 113                 if (port->bulk_out_size) {
 114                         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 115                                 usb_kill_urb(port->write_urbs[i]);
 116
 117                         spin_lock_irqsave(&port->lock, flags);
 118                         kfifo_reset_out(&port->write_fifo);
 119                         spin_unlock_irqrestore(&port->lock, flags);
 120                 }
 121                 if (port->bulk_in_size) {
 122                         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 123                                 usb_kill_urb(port->read_urbs[i]);
 124                 }
 125         }
 126 }
 127
 128 void usb_serial_generic_close(struct usb_serial_port *port)
 129 {
 130         generic_cleanup(port);
 131 }
 132 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 133
 134 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 135                                                 void *dest, size_t size)
 136 {
 137         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 138 }
 139
 140 /**
 141  * usb_serial_generic_write_start - kick off an URB write
 142  * @port:       Pointer to the &struct usb_serial_port data
 143  *
 144  * Returns zero on success, or a negative errno value
 145  */
 146 static int usb_serial_generic_write_start(struct usb_serial_port *port)
 147 {
 148         struct urb *urb;
 149         int count, result;
 150         unsigned long flags;
 151         int i;
 152
 153         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 154                 return 0;
 155 retry:
 156         spin_lock_irqsave(&port->lock, flags);
 157         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 158                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 159                 spin_unlock_irqrestore(&port->lock, flags);
 160                 return 0;
 161         }
 162         i = (int)find_first_bit(&port->write_urbs_free,
 163                                                 ARRAY_SIZE(port->write_urbs));
 164         spin_unlock_irqrestore(&port->lock, flags);
 165
 166         urb = port->write_urbs[i];
 167         count = port->serial->type->prepare_write_buffer(port,
 168                                                 urb->transfer_buffer,
 169                                                 port->bulk_out_size);
 170         urb->transfer_buffer_length = count;
 171         usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
 172         spin_lock_irqsave(&port->lock, flags);
 173         port->tx_bytes += count;
 174         spin_unlock_irqrestore(&port->lock, flags);
 175
 176         clear_bit(i, &port->write_urbs_free);
 177         result = usb_submit_urb(urb, GFP_ATOMIC);
 178         if (result) {
 179                 dev_err_console(port, "%s - error submitting urb: %d\n",
 180                                                 __func__, result);
 181                 set_bit(i, &port->write_urbs_free);
 182                 spin_lock_irqsave(&port->lock, flags);
 183                 port->tx_bytes -= count;
 184                 spin_unlock_irqrestore(&port->lock, flags);
 185
 186                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 187                 return result;
 188         }
 189
 190         /* Try sending off another urb, unless in irq context (in which case
 191          * there will be no free urb). */
 192         if (!in_irq())
 193                 goto retry;
 194
 195         clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 196
 197         return 0;
 198 }
 199
 200 /**
 201  * usb_serial_generic_write - generic write function for serial USB devices
 202  * @tty:        Pointer to &struct tty_struct for the device
 203  * @port:       Pointer to the &usb_serial_port structure for the device
 204  * @buf:        Pointer to the data to write
 205  * @count:      Number of bytes to write
 206  *
 207  * Returns the number of characters actually written, which may be anything
 208  * from zero to @count. If an error occurs, it returns the negative errno
 209  * value.
 210  */
 211 int usb_serial_generic_write(struct tty_struct *tty,
 212         struct usb_serial_port *port, const unsigned char *buf, int count)
 213 {
 214         int result;
 215
 216         /* only do something if we have a bulk out endpoint */
 217         if (!port->bulk_out_size)
 218                 return -ENODEV;
 219
 220         if (!count)
 221                 return 0;
 222
 223         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 224         result = usb_serial_generic_write_start(port);
 225         if (result)
 226                 return result;
 227
 228         return count;
 229 }
 230 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 231
 232 int usb_serial_generic_write_room(struct tty_struct *tty)
 233 {
 234         struct usb_serial_port *port = tty->driver_data;
 235         unsigned long flags;
 236         int room;
 237
 238         if (!port->bulk_out_size)
 239                 return 0;
 240
 241         spin_lock_irqsave(&port->lock, flags);
 242         room = kfifo_avail(&port->write_fifo);
 243         spin_unlock_irqrestore(&port->lock, flags);
 244
 245         dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
 246         return room;
 247 }
 248
 249 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 250 {
 251         struct usb_serial_port *port = tty->driver_data;
 252         unsigned long flags;
 253         int chars;
 254
 255         if (!port->bulk_out_size)
 256                 return 0;
 257
 258         spin_lock_irqsave(&port->lock, flags);
 259         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 260         spin_unlock_irqrestore(&port->lock, flags);
 261
 262         dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
 263         return chars;
 264 }
 265 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
 266
 267 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 268                                                 int index, gfp_t mem_flags)
 269 {
 270         int res;
 271
 272         if (!test_and_clear_bit(index, &port->read_urbs_free))
 273                 return 0;
 274
 275         dev_dbg(&port->dev, "%s - port %d, urb %d\n", __func__,
 276                 port->number, index);
 277
 278         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 279         if (res) {
 280                 if (res != -EPERM) {
 281                         dev_err(&port->dev,
 282                                         "%s - usb_submit_urb failed: %d\n",
 283                                         __func__, res);
 284                 }
 285                 set_bit(index, &port->read_urbs_free);
 286                 return res;
 287         }
 288
 289         return 0;
 290 }
 291
 292 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 293                                         gfp_t mem_flags)
 294 {
 295         int res;
 296         int i;
 297
 298         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 299                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 300                 if (res)
 301                         goto err;
 302         }
 303
 304         return 0;
 305 err:
 306         for (; i >= 0; --i)
 307                 usb_kill_urb(port->read_urbs[i]);
 308
 309         return res;
 310 }
 311 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 312
 313 void usb_serial_generic_process_read_urb(struct urb *urb)
 314 {
 315         struct usb_serial_port *port = urb->context;
 316         char *ch = (char *)urb->transfer_buffer;
 317         int i;
 318
 319         if (!urb->actual_length)
 320                 return;
 321
 322         /* The per character mucking around with sysrq path it too slow for
 323            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 324            where the USB serial is not a console anyway */
 325         if (!port->port.console || !port->sysrq)
 326                 tty_insert_flip_string(&port->port, ch, urb->actual_length);
 327         else {
 328                 for (i = 0; i < urb->actual_length; i++, ch++) {
 329                         if (!usb_serial_handle_sysrq_char(port, *ch))
 330                                 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
 331                 }
 332         }
 333         tty_flip_buffer_push(&port->port);
 334 }
 335 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 336
 337 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 338 {
 339         struct usb_serial_port *port = urb->context;
 340         unsigned char *data = urb->transfer_buffer;
 341         unsigned long flags;
 342         int i;
 343
 344         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 345                 if (urb == port->read_urbs[i])
 346                         break;
 347         }
 348         set_bit(i, &port->read_urbs_free);
 349
 350         dev_dbg(&port->dev, "%s - port %d, urb %d, len %d\n",
 351                 __func__, port->number, i, urb->actual_length);
 352
 353         if (urb->status) {
 354                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 355                         __func__, urb->status);
 356                 return;
 357         }
 358
 359         usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
 360         port->serial->type->process_read_urb(urb);
 361
 362         /* Throttle the device if requested by tty */
 363         spin_lock_irqsave(&port->lock, flags);
 364         port->throttled = port->throttle_req;
 365         if (!port->throttled) {
 366                 spin_unlock_irqrestore(&port->lock, flags);
 367                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 368         } else
 369                 spin_unlock_irqrestore(&port->lock, flags);
 370 }
 371 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 372
 373 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 374 {
 375         unsigned long flags;
 376         struct usb_serial_port *port = urb->context;
 377         int status = urb->status;
 378         int i;
 379
 380         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 381                 if (port->write_urbs[i] == urb)
 382                         break;
 383
 384         spin_lock_irqsave(&port->lock, flags);
 385         port->tx_bytes -= urb->transfer_buffer_length;
 386         set_bit(i, &port->write_urbs_free);
 387         spin_unlock_irqrestore(&port->lock, flags);
 388
 389         if (status) {
 390                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 391                         __func__, status);
 392
 393                 spin_lock_irqsave(&port->lock, flags);
 394                 kfifo_reset_out(&port->write_fifo);
 395                 spin_unlock_irqrestore(&port->lock, flags);
 396         } else {
 397                 usb_serial_generic_write_start(port);
 398         }
 399
 400         usb_serial_port_softint(port);
 401 }
 402 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 403
 404 void usb_serial_generic_throttle(struct tty_struct *tty)
 405 {
 406         struct usb_serial_port *port = tty->driver_data;
 407         unsigned long flags;
 408
 409         /* Set the throttle request flag. It will be picked up
 410          * by usb_serial_generic_read_bulk_callback(). */
 411         spin_lock_irqsave(&port->lock, flags);
 412         port->throttle_req = 1;
 413         spin_unlock_irqrestore(&port->lock, flags);
 414 }
 415 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 416
 417 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 418 {
 419         struct usb_serial_port *port = tty->driver_data;
 420         int was_throttled;
 421
 422         /* Clear the throttle flags */
 423         spin_lock_irq(&port->lock);
 424         was_throttled = port->throttled;
 425         port->throttled = port->throttle_req = 0;
 426         spin_unlock_irq(&port->lock);
 427
 428         if (was_throttled)
 429                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 430 }
 431 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 432
 433 #ifdef CONFIG_MAGIC_SYSRQ
 434 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 435 {
 436         if (port->sysrq && port->port.console) {
 437                 if (ch && time_before(jiffies, port->sysrq)) {
 438                         handle_sysrq(ch);
 439                         port->sysrq = 0;
 440                         return 1;
 441                 }
 442                 port->sysrq = 0;
 443         }
 444         return 0;
 445 }
 446 #else
 447 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 448 {
 449         return 0;
 450 }
 451 #endif
 452 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 453
 454 int usb_serial_handle_break(struct usb_serial_port *port)
 455 {
 456         if (!port->sysrq) {
 457                 port->sysrq = jiffies + HZ*5;
 458                 return 1;
 459         }
 460         port->sysrq = 0;
 461         return 0;
 462 }
 463 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 464
 465 /**
 466  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 467  *      @port: usb_serial_port structure for the open port
 468  *      @tty: tty_struct structure for the port
 469  *      @status: new carrier detect status, nonzero if active
 470  */
 471 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 472                                 struct tty_struct *tty, unsigned int status)
 473 {
 474         struct tty_port *port = &usb_port->port;
 475
 476         dev_dbg(&usb_port->dev, "%s - port %d, status %d\n", __func__,
 477                 usb_port->number, status);
 478
 479         if (status)
 480                 wake_up_interruptible(&port->open_wait);
 481         else if (tty && !C_CLOCAL(tty))
 482                 tty_hangup(tty);
 483 }
 484 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 485
 486 int usb_serial_generic_resume(struct usb_serial *serial)
 487 {
 488         struct usb_serial_port *port;
 489         int i, c = 0, r;
 490
 491         for (i = 0; i < serial->num_ports; i++) {
 492                 port = serial->port[i];
 493                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 494                         continue;
 495
 496                 if (port->bulk_in_size) {
 497                         r = usb_serial_generic_submit_read_urbs(port,
 498                                                                 GFP_NOIO);
 499                         if (r < 0)
 500                                 c++;
 501                 }
 502
 503                 if (port->bulk_out_size) {
 504                         r = usb_serial_generic_write_start(port);
 505                         if (r < 0)
 506                                 c++;
 507                 }
 508         }
 509
 510         return c ? -EIO : 0;
 511 }
 512 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 513
 514 void usb_serial_generic_disconnect(struct usb_serial *serial)
 515 {
 516         int i;
 517
 518         /* stop reads and writes on all ports */
 519         for (i = 0; i < serial->num_ports; ++i)
 520                 generic_cleanup(serial->port[i]);
 521 }
 522 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 523
 524 void usb_serial_generic_release(struct usb_serial *serial)
 525 {
 526 }