drivers/usb/serial/generic.c

   1 /*
   2  * USB Serial Converter Generic functions
   3  *
   4  * Copyright (C) 2010 - 2013 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 #include <linux/kernel.h>
  13 #include <linux/sched/signal.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 struct usb_serial_driver usb_serial_generic_device = {
  41         .driver = {
  42                 .owner =        THIS_MODULE,
  43                 .name =         "generic",
  44         },
  45         .id_table =             generic_device_ids,
  46         .num_ports =            1,
  47         .throttle =             usb_serial_generic_throttle,
  48         .unthrottle =           usb_serial_generic_unthrottle,
  49         .resume =               usb_serial_generic_resume,
  50 };
  51
  52 static struct usb_serial_driver * const serial_drivers[] = {
  53         &usb_serial_generic_device, NULL
  54 };
  55
  56 #endif
  57
  58 int usb_serial_generic_register(void)
  59 {
  60         int retval = 0;
  61
  62 #ifdef CONFIG_USB_SERIAL_GENERIC
  63         generic_device_ids[0].idVendor = vendor;
  64         generic_device_ids[0].idProduct = product;
  65         generic_device_ids[0].match_flags =
  66                 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
  67
  68         retval = usb_serial_register_drivers(serial_drivers,
  69                         "usbserial_generic", generic_device_ids);
  70 #endif
  71         return retval;
  72 }
  73
  74 void usb_serial_generic_deregister(void)
  75 {
  76 #ifdef CONFIG_USB_SERIAL_GENERIC
  77         usb_serial_deregister_drivers(serial_drivers);
  78 #endif
  79 }
  80
  81 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
  82 {
  83         int result = 0;
  84         unsigned long flags;
  85
  86         spin_lock_irqsave(&port->lock, flags);
  87         port->throttled = 0;
  88         port->throttle_req = 0;
  89         spin_unlock_irqrestore(&port->lock, flags);
  90
  91         if (port->bulk_in_size)
  92                 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
  93
  94         return result;
  95 }
  96 EXPORT_SYMBOL_GPL(usb_serial_generic_open);
  97
  98 void usb_serial_generic_close(struct usb_serial_port *port)
  99 {
 100         unsigned long flags;
 101         int i;
 102
 103         if (port->bulk_out_size) {
 104                 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
 105                         usb_kill_urb(port->write_urbs[i]);
 106
 107                 spin_lock_irqsave(&port->lock, flags);
 108                 kfifo_reset_out(&port->write_fifo);
 109                 spin_unlock_irqrestore(&port->lock, flags);
 110         }
 111         if (port->bulk_in_size) {
 112                 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
 113                         usb_kill_urb(port->read_urbs[i]);
 114         }
 115 }
 116 EXPORT_SYMBOL_GPL(usb_serial_generic_close);
 117
 118 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
 119                                                 void *dest, size_t size)
 120 {
 121         return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
 122 }
 123
 124 /**
 125  * usb_serial_generic_write_start - start writing buffered data
 126  * @port: usb-serial port
 127  * @mem_flags: flags to use for memory allocations
 128  *
 129  * Serialised using USB_SERIAL_WRITE_BUSY flag.
 130  *
 131  * Return: Zero on success or if busy, otherwise a negative errno value.
 132  */
 133 int usb_serial_generic_write_start(struct usb_serial_port *port,
 134                                                         gfp_t mem_flags)
 135 {
 136         struct urb *urb;
 137         int count, result;
 138         unsigned long flags;
 139         int i;
 140
 141         if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
 142                 return 0;
 143 retry:
 144         spin_lock_irqsave(&port->lock, flags);
 145         if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
 146                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 147                 spin_unlock_irqrestore(&port->lock, flags);
 148                 return 0;
 149         }
 150         i = (int)find_first_bit(&port->write_urbs_free,
 151                                                 ARRAY_SIZE(port->write_urbs));
 152         spin_unlock_irqrestore(&port->lock, flags);
 153
 154         urb = port->write_urbs[i];
 155         count = port->serial->type->prepare_write_buffer(port,
 156                                                 urb->transfer_buffer,
 157                                                 port->bulk_out_size);
 158         urb->transfer_buffer_length = count;
 159         usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
 160         spin_lock_irqsave(&port->lock, flags);
 161         port->tx_bytes += count;
 162         spin_unlock_irqrestore(&port->lock, flags);
 163
 164         clear_bit(i, &port->write_urbs_free);
 165         result = usb_submit_urb(urb, mem_flags);
 166         if (result) {
 167                 dev_err_console(port, "%s - error submitting urb: %d\n",
 168                                                 __func__, result);
 169                 set_bit(i, &port->write_urbs_free);
 170                 spin_lock_irqsave(&port->lock, flags);
 171                 port->tx_bytes -= count;
 172                 spin_unlock_irqrestore(&port->lock, flags);
 173
 174                 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
 175                 return result;
 176         }
 177
 178         goto retry;     /* try sending off another urb */
 179 }
 180 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start);
 181
 182 /**
 183  * usb_serial_generic_write - generic write function
 184  * @tty: tty for the port
 185  * @port: usb-serial port
 186  * @buf: data to write
 187  * @count: number of bytes to write
 188  *
 189  * Return: The number of characters buffered, which may be anything from
 190  * zero to @count, or a negative errno value.
 191  */
 192 int usb_serial_generic_write(struct tty_struct *tty,
 193         struct usb_serial_port *port, const unsigned char *buf, int count)
 194 {
 195         int result;
 196
 197         if (!port->bulk_out_size)
 198                 return -ENODEV;
 199
 200         if (!count)
 201                 return 0;
 202
 203         count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
 204         result = usb_serial_generic_write_start(port, GFP_ATOMIC);
 205         if (result)
 206                 return result;
 207
 208         return count;
 209 }
 210 EXPORT_SYMBOL_GPL(usb_serial_generic_write);
 211
 212 int usb_serial_generic_write_room(struct tty_struct *tty)
 213 {
 214         struct usb_serial_port *port = tty->driver_data;
 215         unsigned long flags;
 216         int room;
 217
 218         if (!port->bulk_out_size)
 219                 return 0;
 220
 221         spin_lock_irqsave(&port->lock, flags);
 222         room = kfifo_avail(&port->write_fifo);
 223         spin_unlock_irqrestore(&port->lock, flags);
 224
 225         dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
 226         return room;
 227 }
 228
 229 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
 230 {
 231         struct usb_serial_port *port = tty->driver_data;
 232         unsigned long flags;
 233         int chars;
 234
 235         if (!port->bulk_out_size)
 236                 return 0;
 237
 238         spin_lock_irqsave(&port->lock, flags);
 239         chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
 240         spin_unlock_irqrestore(&port->lock, flags);
 241
 242         dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
 243         return chars;
 244 }
 245 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
 246
 247 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
 248 {
 249         struct usb_serial_port *port = tty->driver_data;
 250         unsigned int bps;
 251         unsigned long period;
 252         unsigned long expire;
 253
 254         bps = tty_get_baud_rate(tty);
 255         if (!bps)
 256                 bps = 9600;     /* B0 */
 257         /*
 258          * Use a poll-period of roughly the time it takes to send one
 259          * character or at least one jiffy.
 260          */
 261         period = max_t(unsigned long, (10 * HZ / bps), 1);
 262         if (timeout)
 263                 period = min_t(unsigned long, period, timeout);
 264
 265         dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
 266                                         __func__, jiffies_to_msecs(timeout),
 267                                         jiffies_to_msecs(period));
 268         expire = jiffies + timeout;
 269         while (!port->serial->type->tx_empty(port)) {
 270                 schedule_timeout_interruptible(period);
 271                 if (signal_pending(current))
 272                         break;
 273                 if (timeout && time_after(jiffies, expire))
 274                         break;
 275         }
 276 }
 277 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
 278
 279 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
 280                                                 int index, gfp_t mem_flags)
 281 {
 282         int res;
 283
 284         if (!test_and_clear_bit(index, &port->read_urbs_free))
 285                 return 0;
 286
 287         dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
 288
 289         res = usb_submit_urb(port->read_urbs[index], mem_flags);
 290         if (res) {
 291                 if (res != -EPERM && res != -ENODEV) {
 292                         dev_err(&port->dev,
 293                                         "%s - usb_submit_urb failed: %d\n",
 294                                         __func__, res);
 295                 }
 296                 set_bit(index, &port->read_urbs_free);
 297                 return res;
 298         }
 299
 300         return 0;
 301 }
 302
 303 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
 304                                         gfp_t mem_flags)
 305 {
 306         int res;
 307         int i;
 308
 309         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 310                 res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
 311                 if (res)
 312                         goto err;
 313         }
 314
 315         return 0;
 316 err:
 317         for (; i >= 0; --i)
 318                 usb_kill_urb(port->read_urbs[i]);
 319
 320         return res;
 321 }
 322 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
 323
 324 void usb_serial_generic_process_read_urb(struct urb *urb)
 325 {
 326         struct usb_serial_port *port = urb->context;
 327         char *ch = (char *)urb->transfer_buffer;
 328         int i;
 329
 330         if (!urb->actual_length)
 331                 return;
 332         /*
 333          * The per character mucking around with sysrq path it too slow for
 334          * stuff like 3G modems, so shortcircuit it in the 99.9999999% of
 335          * cases where the USB serial is not a console anyway.
 336          */
 337         if (!port->port.console || !port->sysrq) {
 338                 tty_insert_flip_string(&port->port, ch, urb->actual_length);
 339         } else {
 340                 for (i = 0; i < urb->actual_length; i++, ch++) {
 341                         if (!usb_serial_handle_sysrq_char(port, *ch))
 342                                 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
 343                 }
 344         }
 345         tty_flip_buffer_push(&port->port);
 346 }
 347 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
 348
 349 void usb_serial_generic_read_bulk_callback(struct urb *urb)
 350 {
 351         struct usb_serial_port *port = urb->context;
 352         unsigned char *data = urb->transfer_buffer;
 353         unsigned long flags;
 354         int status = urb->status;
 355         int i;
 356
 357         for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
 358                 if (urb == port->read_urbs[i])
 359                         break;
 360         }
 361         set_bit(i, &port->read_urbs_free);
 362
 363         dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
 364                                                         urb->actual_length);
 365         switch (status) {
 366         case 0:
 367                 break;
 368         case -ENOENT:
 369         case -ECONNRESET:
 370         case -ESHUTDOWN:
 371                 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
 372                                                         __func__, status);
 373                 return;
 374         case -EPIPE:
 375                 dev_err(&port->dev, "%s - urb stopped: %d\n",
 376                                                         __func__, status);
 377                 return;
 378         default:
 379                 dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
 380                                                         __func__, status);
 381                 goto resubmit;
 382         }
 383
 384         usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
 385         port->serial->type->process_read_urb(urb);
 386
 387 resubmit:
 388         /* Throttle the device if requested by tty */
 389         spin_lock_irqsave(&port->lock, flags);
 390         port->throttled = port->throttle_req;
 391         if (!port->throttled) {
 392                 spin_unlock_irqrestore(&port->lock, flags);
 393                 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
 394         } else {
 395                 spin_unlock_irqrestore(&port->lock, flags);
 396         }
 397 }
 398 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
 399
 400 void usb_serial_generic_write_bulk_callback(struct urb *urb)
 401 {
 402         unsigned long flags;
 403         struct usb_serial_port *port = urb->context;
 404         int status = urb->status;
 405         int i;
 406
 407         for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) {
 408                 if (port->write_urbs[i] == urb)
 409                         break;
 410         }
 411         spin_lock_irqsave(&port->lock, flags);
 412         port->tx_bytes -= urb->transfer_buffer_length;
 413         set_bit(i, &port->write_urbs_free);
 414         spin_unlock_irqrestore(&port->lock, flags);
 415
 416         switch (status) {
 417         case 0:
 418                 break;
 419         case -ENOENT:
 420         case -ECONNRESET:
 421         case -ESHUTDOWN:
 422                 dev_dbg(&port->dev, "%s - urb stopped: %d\n",
 423                                                         __func__, status);
 424                 return;
 425         case -EPIPE:
 426                 dev_err_console(port, "%s - urb stopped: %d\n",
 427                                                         __func__, status);
 428                 return;
 429         default:
 430                 dev_err_console(port, "%s - nonzero urb status: %d\n",
 431                                                         __func__, status);
 432                 goto resubmit;
 433         }
 434
 435 resubmit:
 436         usb_serial_generic_write_start(port, GFP_ATOMIC);
 437         usb_serial_port_softint(port);
 438 }
 439 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
 440
 441 void usb_serial_generic_throttle(struct tty_struct *tty)
 442 {
 443         struct usb_serial_port *port = tty->driver_data;
 444         unsigned long flags;
 445
 446         spin_lock_irqsave(&port->lock, flags);
 447         port->throttle_req = 1;
 448         spin_unlock_irqrestore(&port->lock, flags);
 449 }
 450 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
 451
 452 void usb_serial_generic_unthrottle(struct tty_struct *tty)
 453 {
 454         struct usb_serial_port *port = tty->driver_data;
 455         int was_throttled;
 456
 457         spin_lock_irq(&port->lock);
 458         was_throttled = port->throttled;
 459         port->throttled = port->throttle_req = 0;
 460         spin_unlock_irq(&port->lock);
 461
 462         if (was_throttled)
 463                 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
 464 }
 465 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
 466
 467 static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
 468                                 unsigned long arg, struct async_icount *cprev)
 469 {
 470         struct usb_serial_port *port = tty->driver_data;
 471         struct async_icount cnow;
 472         unsigned long flags;
 473         bool ret;
 474
 475         /*
 476          * Use tty-port initialised flag to detect all hangups including the
 477          * one generated at USB-device disconnect.
 478          */
 479         if (!tty_port_initialized(&port->port))
 480                 return true;
 481
 482         spin_lock_irqsave(&port->lock, flags);
 483         cnow = port->icount;                            /* atomic copy*/
 484         spin_unlock_irqrestore(&port->lock, flags);
 485
 486         ret =   ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
 487                 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
 488                 ((arg & TIOCM_CD)  && (cnow.dcd != cprev->dcd)) ||
 489                 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
 490
 491         *cprev = cnow;
 492
 493         return ret;
 494 }
 495
 496 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
 497 {
 498         struct usb_serial_port *port = tty->driver_data;
 499         struct async_icount cnow;
 500         unsigned long flags;
 501         int ret;
 502
 503         spin_lock_irqsave(&port->lock, flags);
 504         cnow = port->icount;                            /* atomic copy */
 505         spin_unlock_irqrestore(&port->lock, flags);
 506
 507         ret = wait_event_interruptible(port->port.delta_msr_wait,
 508                         usb_serial_generic_msr_changed(tty, arg, &cnow));
 509         if (!ret && !tty_port_initialized(&port->port))
 510                 ret = -EIO;
 511
 512         return ret;
 513 }
 514 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
 515
 516 int usb_serial_generic_get_icount(struct tty_struct *tty,
 517                                         struct serial_icounter_struct *icount)
 518 {
 519         struct usb_serial_port *port = tty->driver_data;
 520         struct async_icount cnow;
 521         unsigned long flags;
 522
 523         spin_lock_irqsave(&port->lock, flags);
 524         cnow = port->icount;                            /* atomic copy */
 525         spin_unlock_irqrestore(&port->lock, flags);
 526
 527         icount->cts = cnow.cts;
 528         icount->dsr = cnow.dsr;
 529         icount->rng = cnow.rng;
 530         icount->dcd = cnow.dcd;
 531         icount->tx = cnow.tx;
 532         icount->rx = cnow.rx;
 533         icount->frame = cnow.frame;
 534         icount->parity = cnow.parity;
 535         icount->overrun = cnow.overrun;
 536         icount->brk = cnow.brk;
 537         icount->buf_overrun = cnow.buf_overrun;
 538
 539         return 0;
 540 }
 541 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
 542
 543 #ifdef CONFIG_MAGIC_SYSRQ
 544 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 545 {
 546         if (port->sysrq && port->port.console) {
 547                 if (ch && time_before(jiffies, port->sysrq)) {
 548                         handle_sysrq(ch);
 549                         port->sysrq = 0;
 550                         return 1;
 551                 }
 552                 port->sysrq = 0;
 553         }
 554         return 0;
 555 }
 556 #else
 557 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
 558 {
 559         return 0;
 560 }
 561 #endif
 562 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
 563
 564 int usb_serial_handle_break(struct usb_serial_port *port)
 565 {
 566         if (!port->sysrq) {
 567                 port->sysrq = jiffies + HZ*5;
 568                 return 1;
 569         }
 570         port->sysrq = 0;
 571         return 0;
 572 }
 573 EXPORT_SYMBOL_GPL(usb_serial_handle_break);
 574
 575 /**
 576  * usb_serial_handle_dcd_change - handle a change of carrier detect state
 577  * @port: usb-serial port
 578  * @tty: tty for the port
 579  * @status: new carrier detect status, nonzero if active
 580  */
 581 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
 582                                 struct tty_struct *tty, unsigned int status)
 583 {
 584         struct tty_port *port = &usb_port->port;
 585
 586         dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
 587
 588         if (tty) {
 589                 struct tty_ldisc *ld = tty_ldisc_ref(tty);
 590
 591                 if (ld) {
 592                         if (ld->ops->dcd_change)
 593                                 ld->ops->dcd_change(tty, status);
 594                         tty_ldisc_deref(ld);
 595                 }
 596         }
 597
 598         if (status)
 599                 wake_up_interruptible(&port->open_wait);
 600         else if (tty && !C_CLOCAL(tty))
 601                 tty_hangup(tty);
 602 }
 603 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
 604
 605 int usb_serial_generic_resume(struct usb_serial *serial)
 606 {
 607         struct usb_serial_port *port;
 608         int i, c = 0, r;
 609
 610         for (i = 0; i < serial->num_ports; i++) {
 611                 port = serial->port[i];
 612                 if (!tty_port_initialized(&port->port))
 613                         continue;
 614
 615                 if (port->bulk_in_size) {
 616                         r = usb_serial_generic_submit_read_urbs(port,
 617                                                                 GFP_NOIO);
 618                         if (r < 0)
 619                                 c++;
 620                 }
 621
 622                 if (port->bulk_out_size) {
 623                         r = usb_serial_generic_write_start(port, GFP_NOIO);
 624                         if (r < 0)
 625                                 c++;
 626                 }
 627         }
 628
 629         return c ? -EIO : 0;
 630 }
 631 EXPORT_SYMBOL_GPL(usb_serial_generic_resume);