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 static int usb_serial_generic_probe(struct usb_serial *serial, 41 const struct usb_device_id *id) 42 { 43 struct device *dev = &serial->interface->dev; 44 45 dev_info(dev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n"); 46 dev_info(dev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n"); 47 48 return 0; 49 } 50 51 static int usb_serial_generic_calc_num_ports(struct usb_serial *serial, 52 struct usb_serial_endpoints *epds) 53 { 54 struct device *dev = &serial->interface->dev; 55 int num_ports; 56 57 num_ports = max(epds->num_bulk_in, epds->num_bulk_out); 58 59 if (num_ports == 0) { 60 dev_err(dev, "device has no bulk endpoints\n"); 61 return -ENODEV; 62 } 63 64 return num_ports; 65 } 66 67 static struct usb_serial_driver usb_serial_generic_device = { 68 .driver = { 69 .owner = THIS_MODULE, 70 .name = "generic", 71 }, 72 .id_table = generic_device_ids, 73 .probe = usb_serial_generic_probe, 74 .calc_num_ports = usb_serial_generic_calc_num_ports, 75 .throttle = usb_serial_generic_throttle, 76 .unthrottle = usb_serial_generic_unthrottle, 77 .resume = usb_serial_generic_resume, 78 }; 79 80 static struct usb_serial_driver * const serial_drivers[] = { 81 &usb_serial_generic_device, NULL 82 }; 83 84 #endif 85 86 int usb_serial_generic_register(void) 87 { 88 int retval = 0; 89 90 #ifdef CONFIG_USB_SERIAL_GENERIC 91 generic_device_ids[0].idVendor = vendor; 92 generic_device_ids[0].idProduct = product; 93 generic_device_ids[0].match_flags = 94 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT; 95 96 retval = usb_serial_register_drivers(serial_drivers, 97 "usbserial_generic", generic_device_ids); 98 #endif 99 return retval; 100 } 101 102 void usb_serial_generic_deregister(void) 103 { 104 #ifdef CONFIG_USB_SERIAL_GENERIC 105 usb_serial_deregister_drivers(serial_drivers); 106 #endif 107 } 108 109 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port) 110 { 111 int result = 0; 112 unsigned long flags; 113 114 spin_lock_irqsave(&port->lock, flags); 115 port->throttled = 0; 116 port->throttle_req = 0; 117 spin_unlock_irqrestore(&port->lock, flags); 118 119 if (port->bulk_in_size) 120 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 121 122 return result; 123 } 124 EXPORT_SYMBOL_GPL(usb_serial_generic_open); 125 126 void usb_serial_generic_close(struct usb_serial_port *port) 127 { 128 unsigned long flags; 129 int i; 130 131 if (port->bulk_out_size) { 132 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) 133 usb_kill_urb(port->write_urbs[i]); 134 135 spin_lock_irqsave(&port->lock, flags); 136 kfifo_reset_out(&port->write_fifo); 137 spin_unlock_irqrestore(&port->lock, flags); 138 } 139 if (port->bulk_in_size) { 140 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) 141 usb_kill_urb(port->read_urbs[i]); 142 } 143 } 144 EXPORT_SYMBOL_GPL(usb_serial_generic_close); 145 146 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port, 147 void *dest, size_t size) 148 { 149 return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock); 150 } 151 152 /** 153 * usb_serial_generic_write_start - start writing buffered data 154 * @port: usb-serial port 155 * @mem_flags: flags to use for memory allocations 156 * 157 * Serialised using USB_SERIAL_WRITE_BUSY flag. 158 * 159 * Return: Zero on success or if busy, otherwise a negative errno value. 160 */ 161 int usb_serial_generic_write_start(struct usb_serial_port *port, 162 gfp_t mem_flags) 163 { 164 struct urb *urb; 165 int count, result; 166 unsigned long flags; 167 int i; 168 169 if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags)) 170 return 0; 171 retry: 172 spin_lock_irqsave(&port->lock, flags); 173 if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) { 174 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 175 spin_unlock_irqrestore(&port->lock, flags); 176 return 0; 177 } 178 i = (int)find_first_bit(&port->write_urbs_free, 179 ARRAY_SIZE(port->write_urbs)); 180 spin_unlock_irqrestore(&port->lock, flags); 181 182 urb = port->write_urbs[i]; 183 count = port->serial->type->prepare_write_buffer(port, 184 urb->transfer_buffer, 185 port->bulk_out_size); 186 urb->transfer_buffer_length = count; 187 usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer); 188 spin_lock_irqsave(&port->lock, flags); 189 port->tx_bytes += count; 190 spin_unlock_irqrestore(&port->lock, flags); 191 192 clear_bit(i, &port->write_urbs_free); 193 result = usb_submit_urb(urb, mem_flags); 194 if (result) { 195 dev_err_console(port, "%s - error submitting urb: %d\n", 196 __func__, result); 197 set_bit(i, &port->write_urbs_free); 198 spin_lock_irqsave(&port->lock, flags); 199 port->tx_bytes -= count; 200 spin_unlock_irqrestore(&port->lock, flags); 201 202 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 203 return result; 204 } 205 206 goto retry; /* try sending off another urb */ 207 } 208 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start); 209 210 /** 211 * usb_serial_generic_write - generic write function 212 * @tty: tty for the port 213 * @port: usb-serial port 214 * @buf: data to write 215 * @count: number of bytes to write 216 * 217 * Return: The number of characters buffered, which may be anything from 218 * zero to @count, or a negative errno value. 219 */ 220 int usb_serial_generic_write(struct tty_struct *tty, 221 struct usb_serial_port *port, const unsigned char *buf, int count) 222 { 223 int result; 224 225 if (!port->bulk_out_size) 226 return -ENODEV; 227 228 if (!count) 229 return 0; 230 231 count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock); 232 result = usb_serial_generic_write_start(port, GFP_ATOMIC); 233 if (result) 234 return result; 235 236 return count; 237 } 238 EXPORT_SYMBOL_GPL(usb_serial_generic_write); 239 240 int usb_serial_generic_write_room(struct tty_struct *tty) 241 { 242 struct usb_serial_port *port = tty->driver_data; 243 unsigned long flags; 244 int room; 245 246 if (!port->bulk_out_size) 247 return 0; 248 249 spin_lock_irqsave(&port->lock, flags); 250 room = kfifo_avail(&port->write_fifo); 251 spin_unlock_irqrestore(&port->lock, flags); 252 253 dev_dbg(&port->dev, "%s - returns %d\n", __func__, room); 254 return room; 255 } 256 257 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty) 258 { 259 struct usb_serial_port *port = tty->driver_data; 260 unsigned long flags; 261 int chars; 262 263 if (!port->bulk_out_size) 264 return 0; 265 266 spin_lock_irqsave(&port->lock, flags); 267 chars = kfifo_len(&port->write_fifo) + port->tx_bytes; 268 spin_unlock_irqrestore(&port->lock, flags); 269 270 dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars); 271 return chars; 272 } 273 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer); 274 275 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout) 276 { 277 struct usb_serial_port *port = tty->driver_data; 278 unsigned int bps; 279 unsigned long period; 280 unsigned long expire; 281 282 bps = tty_get_baud_rate(tty); 283 if (!bps) 284 bps = 9600; /* B0 */ 285 /* 286 * Use a poll-period of roughly the time it takes to send one 287 * character or at least one jiffy. 288 */ 289 period = max_t(unsigned long, (10 * HZ / bps), 1); 290 if (timeout) 291 period = min_t(unsigned long, period, timeout); 292 293 dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n", 294 __func__, jiffies_to_msecs(timeout), 295 jiffies_to_msecs(period)); 296 expire = jiffies + timeout; 297 while (!port->serial->type->tx_empty(port)) { 298 schedule_timeout_interruptible(period); 299 if (signal_pending(current)) 300 break; 301 if (timeout && time_after(jiffies, expire)) 302 break; 303 } 304 } 305 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent); 306 307 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port, 308 int index, gfp_t mem_flags) 309 { 310 int res; 311 312 if (!test_and_clear_bit(index, &port->read_urbs_free)) 313 return 0; 314 315 dev_dbg(&port->dev, "%s - urb %d\n", __func__, index); 316 317 res = usb_submit_urb(port->read_urbs[index], mem_flags); 318 if (res) { 319 if (res != -EPERM && res != -ENODEV) { 320 dev_err(&port->dev, 321 "%s - usb_submit_urb failed: %d\n", 322 __func__, res); 323 } 324 set_bit(index, &port->read_urbs_free); 325 return res; 326 } 327 328 return 0; 329 } 330 331 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port, 332 gfp_t mem_flags) 333 { 334 int res; 335 int i; 336 337 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 338 res = usb_serial_generic_submit_read_urb(port, i, mem_flags); 339 if (res) 340 goto err; 341 } 342 343 return 0; 344 err: 345 for (; i >= 0; --i) 346 usb_kill_urb(port->read_urbs[i]); 347 348 return res; 349 } 350 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs); 351 352 void usb_serial_generic_process_read_urb(struct urb *urb) 353 { 354 struct usb_serial_port *port = urb->context; 355 char *ch = (char *)urb->transfer_buffer; 356 int i; 357 358 if (!urb->actual_length) 359 return; 360 /* 361 * The per character mucking around with sysrq path it too slow for 362 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of 363 * cases where the USB serial is not a console anyway. 364 */ 365 if (!port->port.console || !port->sysrq) { 366 tty_insert_flip_string(&port->port, ch, urb->actual_length); 367 } else { 368 for (i = 0; i < urb->actual_length; i++, ch++) { 369 if (!usb_serial_handle_sysrq_char(port, *ch)) 370 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL); 371 } 372 } 373 tty_flip_buffer_push(&port->port); 374 } 375 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb); 376 377 void usb_serial_generic_read_bulk_callback(struct urb *urb) 378 { 379 struct usb_serial_port *port = urb->context; 380 unsigned char *data = urb->transfer_buffer; 381 unsigned long flags; 382 int status = urb->status; 383 int i; 384 385 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 386 if (urb == port->read_urbs[i]) 387 break; 388 } 389 set_bit(i, &port->read_urbs_free); 390 391 dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i, 392 urb->actual_length); 393 switch (status) { 394 case 0: 395 break; 396 case -ENOENT: 397 case -ECONNRESET: 398 case -ESHUTDOWN: 399 dev_dbg(&port->dev, "%s - urb stopped: %d\n", 400 __func__, status); 401 return; 402 case -EPIPE: 403 dev_err(&port->dev, "%s - urb stopped: %d\n", 404 __func__, status); 405 return; 406 default: 407 dev_dbg(&port->dev, "%s - nonzero urb status: %d\n", 408 __func__, status); 409 goto resubmit; 410 } 411 412 usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data); 413 port->serial->type->process_read_urb(urb); 414 415 resubmit: 416 /* Throttle the device if requested by tty */ 417 spin_lock_irqsave(&port->lock, flags); 418 port->throttled = port->throttle_req; 419 if (!port->throttled) { 420 spin_unlock_irqrestore(&port->lock, flags); 421 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC); 422 } else { 423 spin_unlock_irqrestore(&port->lock, flags); 424 } 425 } 426 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback); 427 428 void usb_serial_generic_write_bulk_callback(struct urb *urb) 429 { 430 unsigned long flags; 431 struct usb_serial_port *port = urb->context; 432 int status = urb->status; 433 int i; 434 435 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) { 436 if (port->write_urbs[i] == urb) 437 break; 438 } 439 spin_lock_irqsave(&port->lock, flags); 440 port->tx_bytes -= urb->transfer_buffer_length; 441 set_bit(i, &port->write_urbs_free); 442 spin_unlock_irqrestore(&port->lock, flags); 443 444 switch (status) { 445 case 0: 446 break; 447 case -ENOENT: 448 case -ECONNRESET: 449 case -ESHUTDOWN: 450 dev_dbg(&port->dev, "%s - urb stopped: %d\n", 451 __func__, status); 452 return; 453 case -EPIPE: 454 dev_err_console(port, "%s - urb stopped: %d\n", 455 __func__, status); 456 return; 457 default: 458 dev_err_console(port, "%s - nonzero urb status: %d\n", 459 __func__, status); 460 goto resubmit; 461 } 462 463 resubmit: 464 usb_serial_generic_write_start(port, GFP_ATOMIC); 465 usb_serial_port_softint(port); 466 } 467 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback); 468 469 void usb_serial_generic_throttle(struct tty_struct *tty) 470 { 471 struct usb_serial_port *port = tty->driver_data; 472 unsigned long flags; 473 474 spin_lock_irqsave(&port->lock, flags); 475 port->throttle_req = 1; 476 spin_unlock_irqrestore(&port->lock, flags); 477 } 478 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle); 479 480 void usb_serial_generic_unthrottle(struct tty_struct *tty) 481 { 482 struct usb_serial_port *port = tty->driver_data; 483 int was_throttled; 484 485 spin_lock_irq(&port->lock); 486 was_throttled = port->throttled; 487 port->throttled = port->throttle_req = 0; 488 spin_unlock_irq(&port->lock); 489 490 if (was_throttled) 491 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 492 } 493 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle); 494 495 static bool usb_serial_generic_msr_changed(struct tty_struct *tty, 496 unsigned long arg, struct async_icount *cprev) 497 { 498 struct usb_serial_port *port = tty->driver_data; 499 struct async_icount cnow; 500 unsigned long flags; 501 bool ret; 502 503 /* 504 * Use tty-port initialised flag to detect all hangups including the 505 * one generated at USB-device disconnect. 506 */ 507 if (!tty_port_initialized(&port->port)) 508 return true; 509 510 spin_lock_irqsave(&port->lock, flags); 511 cnow = port->icount; /* atomic copy*/ 512 spin_unlock_irqrestore(&port->lock, flags); 513 514 ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) || 515 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) || 516 ((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) || 517 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts)); 518 519 *cprev = cnow; 520 521 return ret; 522 } 523 524 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg) 525 { 526 struct usb_serial_port *port = tty->driver_data; 527 struct async_icount cnow; 528 unsigned long flags; 529 int ret; 530 531 spin_lock_irqsave(&port->lock, flags); 532 cnow = port->icount; /* atomic copy */ 533 spin_unlock_irqrestore(&port->lock, flags); 534 535 ret = wait_event_interruptible(port->port.delta_msr_wait, 536 usb_serial_generic_msr_changed(tty, arg, &cnow)); 537 if (!ret && !tty_port_initialized(&port->port)) 538 ret = -EIO; 539 540 return ret; 541 } 542 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait); 543 544 int usb_serial_generic_get_icount(struct tty_struct *tty, 545 struct serial_icounter_struct *icount) 546 { 547 struct usb_serial_port *port = tty->driver_data; 548 struct async_icount cnow; 549 unsigned long flags; 550 551 spin_lock_irqsave(&port->lock, flags); 552 cnow = port->icount; /* atomic copy */ 553 spin_unlock_irqrestore(&port->lock, flags); 554 555 icount->cts = cnow.cts; 556 icount->dsr = cnow.dsr; 557 icount->rng = cnow.rng; 558 icount->dcd = cnow.dcd; 559 icount->tx = cnow.tx; 560 icount->rx = cnow.rx; 561 icount->frame = cnow.frame; 562 icount->parity = cnow.parity; 563 icount->overrun = cnow.overrun; 564 icount->brk = cnow.brk; 565 icount->buf_overrun = cnow.buf_overrun; 566 567 return 0; 568 } 569 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount); 570 571 #ifdef CONFIG_MAGIC_SYSRQ 572 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 573 { 574 if (port->sysrq && port->port.console) { 575 if (ch && time_before(jiffies, port->sysrq)) { 576 handle_sysrq(ch); 577 port->sysrq = 0; 578 return 1; 579 } 580 port->sysrq = 0; 581 } 582 return 0; 583 } 584 #else 585 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 586 { 587 return 0; 588 } 589 #endif 590 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char); 591 592 int usb_serial_handle_break(struct usb_serial_port *port) 593 { 594 if (!port->sysrq) { 595 port->sysrq = jiffies + HZ*5; 596 return 1; 597 } 598 port->sysrq = 0; 599 return 0; 600 } 601 EXPORT_SYMBOL_GPL(usb_serial_handle_break); 602 603 /** 604 * usb_serial_handle_dcd_change - handle a change of carrier detect state 605 * @port: usb-serial port 606 * @tty: tty for the port 607 * @status: new carrier detect status, nonzero if active 608 */ 609 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port, 610 struct tty_struct *tty, unsigned int status) 611 { 612 struct tty_port *port = &usb_port->port; 613 614 dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status); 615 616 if (tty) { 617 struct tty_ldisc *ld = tty_ldisc_ref(tty); 618 619 if (ld) { 620 if (ld->ops->dcd_change) 621 ld->ops->dcd_change(tty, status); 622 tty_ldisc_deref(ld); 623 } 624 } 625 626 if (status) 627 wake_up_interruptible(&port->open_wait); 628 else if (tty && !C_CLOCAL(tty)) 629 tty_hangup(tty); 630 } 631 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change); 632 633 int usb_serial_generic_resume(struct usb_serial *serial) 634 { 635 struct usb_serial_port *port; 636 int i, c = 0, r; 637 638 for (i = 0; i < serial->num_ports; i++) { 639 port = serial->port[i]; 640 if (!tty_port_initialized(&port->port)) 641 continue; 642 643 if (port->bulk_in_size) { 644 r = usb_serial_generic_submit_read_urbs(port, 645 GFP_NOIO); 646 if (r < 0) 647 c++; 648 } 649 650 if (port->bulk_out_size) { 651 r = usb_serial_generic_write_start(port, GFP_NOIO); 652 if (r < 0) 653 c++; 654 } 655 } 656 657 return c ? -EIO : 0; 658 } 659 EXPORT_SYMBOL_GPL(usb_serial_generic_resume); 660