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
 266 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 267                                                 int index, gfp_t mem_flags)
 268 {
 269         int res;
 270
 271         if (!test_and_clear_bit(index, &port->read_urbs_free))
 272                 return 0;
 273
 274         dev_dbg(&port->dev, "%s - port %d, urb %d\n", __func__,
 275                 port->number, index);
 276
 277         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 278         if (res) {
 279                 if (res != -EPERM) {
 280                         dev_err(&port->dev,
 281                                         "%s - usb_submit_urb failed: %d\n",
 282                                         __func__, res);
 283                 }
 284                 set_bit(index, &port->read_urbs_free);
 285                 return res;
 286         }
 287
 288         return 0;
 289 }
 290
 291 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 292                                         gfp_t mem_flags)
 293 {
 294         int res;
 295         int i;
 296
 297         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 298                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 299                 if (res)
 300                         goto err;
 301         }
 302
 303         return 0;
 304 err:
 305         for (; i >= 0; --i)
 306                 usb_kill_urb(port->read_urbs[i]);
 307
 308         return res;
 309 }
 310 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 311
 312 void usb_serial_generic_process_read_urb(struct urb *urb)
 313 {
 314         struct usb_serial_port *port = urb->context;
 315         struct tty_struct *tty;
 316         char *ch = (char *)urb->transfer_buffer;
 317         int i;
 318
 319         if (!urb->actual_length)
 320                 return;
 321
 322         tty = tty_port_tty_get(&port->port);
 323         if (!tty)
 324                 return;
 325
 326         /* The per character mucking around with sysrq path it too slow for
 327            stuff like 3G modems, so shortcircuit it in the 99.9999999% of cases
 328            where the USB serial is not a console anyway */
 329         if (!port->port.console || !port->sysrq)
 330                 tty_insert_flip_string(tty, ch, urb->actual_length);
 331         else {
 332                 for (i = 0; i < urb->actual_length; i++, ch++) {
 333                         if (!usb_serial_handle_sysrq_char(port, *ch))
 334                                 tty_insert_flip_char(tty, *ch, TTY_NORMAL);
 335                 }
 336         }
 337         tty_flip_buffer_push(tty);
 338         tty_kref_put(tty);
 339 }
 340 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 341
 342 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 343 {
 344         struct usb_serial_port *port = urb->context;
 345         unsigned char *data = urb->transfer_buffer;
 346         unsigned long flags;
 347         int i;
 348
 349         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 350                 if (urb == port->read_urbs[i])
 351                         break;
 352         }
 353         set_bit(i, &port->read_urbs_free);
 354
 355         dev_dbg(&port->dev, "%s - port %d, urb %d, len %d\n",
 356                 __func__, port->number, i, urb->actual_length);
 357
 358         if (urb->status) {
 359                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 360                         __func__, urb->status);
 361                 return;
 362         }
 363
 364         usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
 365         port->serial->type->process_read_urb(urb);
 366
 367         /* Throttle the device if requested by tty */
 368         spin_lock_irqsave(&port->lock, flags);
 369         port->throttled = port->throttle_req;
 370         if (!port->throttled) {
 371                 spin_unlock_irqrestore(&port->lock, flags);
 372                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 373         } else
 374                 spin_unlock_irqrestore(&port->lock, flags);
 375 }
 376 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 377
 378 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 379 {
 380         unsigned long flags;
 381         struct usb_serial_port *port = urb->context;
 382         int status = urb->status;
 383         int i;
 384
 385         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 386                 if (port->write_urbs[i] == urb)
 387                         break;
 388
 389         spin_lock_irqsave(&port->lock, flags);
 390         port->tx_bytes -= urb->transfer_buffer_length;
 391         set_bit(i, &port->write_urbs_free);
 392         spin_unlock_irqrestore(&port->lock, flags);
 393
 394         if (status) {
 395                 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
 396                         __func__, status);
 397
 398                 spin_lock_irqsave(&port->lock, flags);
 399                 kfifo_reset_out(&port->write_fifo);
 400                 spin_unlock_irqrestore(&port->lock, flags);
 401         } else {
 402                 usb_serial_generic_write_start(port);
 403         }
 404
 405         usb_serial_port_softint(port);
 406 }
 407 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 408
 409 void usb_serial_generic_throttle(struct tty_struct *tty)
 410 {
 411         struct usb_serial_port *port = tty->driver_data;
 412         unsigned long flags;
 413
 414         /* Set the throttle request flag. It will be picked up
 415          * by usb_serial_generic_read_bulk_callback(). */
 416         spin_lock_irqsave(&port->lock, flags);
 417         port->throttle_req = 1;
 418         spin_unlock_irqrestore(&port->lock, flags);
 419 }
 420 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 421
 422 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 423 {
 424         struct usb_serial_port *port = tty->driver_data;
 425         int was_throttled;
 426
 427         /* Clear the throttle flags */
 428         spin_lock_irq(&port->lock);
 429         was_throttled = port->throttled;
 430         port->throttled = port->throttle_req = 0;
 431         spin_unlock_irq(&port->lock);
 432
 433         if (was_throttled)
 434                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 435 }
 436 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 437
 438 #ifdef CONFIG_MAGIC_SYSRQ
 439 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 440 {
 441         if (port->sysrq && port->port.console) {
 442                 if (ch && time_before(jiffies, port->sysrq)) {
 443                         handle_sysrq(ch);
 444                         port->sysrq = 0;
 445                         return 1;
 446                 }
 447                 port->sysrq = 0;
 448         }
 449         return 0;
 450 }
 451 #else
 452 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 453 {
 454         return 0;
 455 }
 456 #endif
 457 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 458
 459 int usb_serial_handle_break(struct usb_serial_port *port)
 460 {
 461         if (!port->sysrq) {
 462                 port->sysrq = jiffies + HZ*5;
 463                 return 1;
 464         }
 465         port->sysrq = 0;
 466         return 0;
 467 }
 468 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 469
 470 /**
 471  *      usb_serial_handle_dcd_change - handle a change of carrier detect state
 472  *      @port: usb_serial_port structure for the open port
 473  *      @tty: tty_struct structure for the port
 474  *      @status: new carrier detect status, nonzero if active
 475  */
 476 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 477                                 struct tty_struct *tty, unsigned int status)
 478 {
 479         struct tty_port *port = &usb_port->port;
 480
 481         dev_dbg(&usb_port->dev, "%s - port %d, status %d\n", __func__,
 482                 usb_port->number, status);
 483
 484         if (status)
 485                 wake_up_interruptible(&port->open_wait);
 486         else if (tty && !C_CLOCAL(tty))
 487                 tty_hangup(tty);
 488 }
 489 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 490
 491 int usb_serial_generic_resume(struct usb_serial *serial)
 492 {
 493         struct usb_serial_port *port;
 494         int i, c = 0, r;
 495
 496         for (i = 0; i < serial->num_ports; i++) {
 497                 port = serial->port[i];
 498                 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
 499                         continue;
 500
 501                 if (port->bulk_in_size) {
 502                         r = usb_serial_generic_submit_read_urbs(port,
 503                                                                 GFP_NOIO);
 504                         if (r < 0)
 505                                 c++;
 506                 }
 507
 508                 if (port->bulk_out_size) {
 509                         r = usb_serial_generic_write_start(port);
 510                         if (r < 0)
 511                                 c++;
 512                 }
 513         }
 514
 515         return c ? -EIO : 0;
 516 }
 517 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);
 518
 519 void usb_serial_generic_disconnect(struct usb_serial *serial)
 520 {
 521         int i;
 522
 523         /* stop reads and writes on all ports */
 524         for (i = 0; i < serial->num_ports; ++i)
 525                 generic_cleanup(serial->port[i]);
 526 }
 527 EXPORT_SYMBOL_GPL(usb_serial_generic_disconnect);
 528
 529 void usb_serial_generic_release(struct usb_serial *serial)
 530 {
 531 }