1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * USB Serial Converter Generic functions 4 * 5 * Copyright (C) 2010 - 2013 Johan Hovold (jhovold@gmail.com) 6 * Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com) 7 */ 8 9 #include <linux/kernel.h> 10 #include <linux/sched/signal.h> 11 #include <linux/errno.h> 12 #include <linux/slab.h> 13 #include <linux/sysrq.h> 14 #include <linux/tty.h> 15 #include <linux/tty_flip.h> 16 #include <linux/module.h> 17 #include <linux/moduleparam.h> 18 #include <linux/usb.h> 19 #include <linux/usb/serial.h> 20 #include <linux/kfifo.h> 21 #include <linux/serial.h> 22 23 #ifdef CONFIG_USB_SERIAL_GENERIC 24 25 static __u16 vendor = 0x05f9; 26 static __u16 product = 0xffff; 27 28 module_param(vendor, ushort, 0); 29 MODULE_PARM_DESC(vendor, "User specified USB idVendor"); 30 31 module_param(product, ushort, 0); 32 MODULE_PARM_DESC(product, "User specified USB idProduct"); 33 34 static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */ 35 36 static int usb_serial_generic_probe(struct usb_serial *serial, 37 const struct usb_device_id *id) 38 { 39 struct device *dev = &serial->interface->dev; 40 41 dev_info(dev, "The \"generic\" usb-serial driver is only for testing and one-off prototypes.\n"); 42 dev_info(dev, "Tell linux-usb@vger.kernel.org to add your device to a proper driver.\n"); 43 44 return 0; 45 } 46 47 static int usb_serial_generic_calc_num_ports(struct usb_serial *serial, 48 struct usb_serial_endpoints *epds) 49 { 50 struct device *dev = &serial->interface->dev; 51 int num_ports; 52 53 num_ports = max(epds->num_bulk_in, epds->num_bulk_out); 54 55 if (num_ports == 0) { 56 dev_err(dev, "device has no bulk endpoints\n"); 57 return -ENODEV; 58 } 59 60 return num_ports; 61 } 62 63 static struct usb_serial_driver usb_serial_generic_device = { 64 .driver = { 65 .name = "generic", 66 }, 67 .id_table = generic_device_ids, 68 .probe = usb_serial_generic_probe, 69 .calc_num_ports = usb_serial_generic_calc_num_ports, 70 .throttle = usb_serial_generic_throttle, 71 .unthrottle = usb_serial_generic_unthrottle, 72 .resume = usb_serial_generic_resume, 73 }; 74 75 static struct usb_serial_driver * const serial_drivers[] = { 76 &usb_serial_generic_device, NULL 77 }; 78 79 #endif 80 81 int usb_serial_generic_register(void) 82 { 83 int retval = 0; 84 85 #ifdef CONFIG_USB_SERIAL_GENERIC 86 generic_device_ids[0].idVendor = vendor; 87 generic_device_ids[0].idProduct = product; 88 generic_device_ids[0].match_flags = 89 USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT; 90 91 retval = usb_serial_register_drivers(serial_drivers, 92 "usbserial_generic", generic_device_ids); 93 #endif 94 return retval; 95 } 96 97 void usb_serial_generic_deregister(void) 98 { 99 #ifdef CONFIG_USB_SERIAL_GENERIC 100 usb_serial_deregister_drivers(serial_drivers); 101 #endif 102 } 103 104 int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port) 105 { 106 int result = 0; 107 108 clear_bit(USB_SERIAL_THROTTLED, &port->flags); 109 110 if (port->bulk_in_size) 111 result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 112 113 return result; 114 } 115 EXPORT_SYMBOL_GPL(usb_serial_generic_open); 116 117 void usb_serial_generic_close(struct usb_serial_port *port) 118 { 119 unsigned long flags; 120 int i; 121 122 if (port->bulk_out_size) { 123 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) 124 usb_kill_urb(port->write_urbs[i]); 125 126 spin_lock_irqsave(&port->lock, flags); 127 kfifo_reset_out(&port->write_fifo); 128 spin_unlock_irqrestore(&port->lock, flags); 129 } 130 if (port->bulk_in_size) { 131 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) 132 usb_kill_urb(port->read_urbs[i]); 133 } 134 } 135 EXPORT_SYMBOL_GPL(usb_serial_generic_close); 136 137 int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port, 138 void *dest, size_t size) 139 { 140 return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock); 141 } 142 143 /** 144 * usb_serial_generic_write_start - start writing buffered data 145 * @port: usb-serial port 146 * @mem_flags: flags to use for memory allocations 147 * 148 * Serialised using USB_SERIAL_WRITE_BUSY flag. 149 * 150 * Return: Zero on success or if busy, otherwise a negative errno value. 151 */ 152 int usb_serial_generic_write_start(struct usb_serial_port *port, 153 gfp_t mem_flags) 154 { 155 struct usb_serial_driver *type = port->serial->type; 156 struct urb *urb; 157 int count, result; 158 unsigned long flags; 159 int i; 160 161 if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags)) 162 return 0; 163 retry: 164 spin_lock_irqsave(&port->lock, flags); 165 if (!port->write_urbs_free || !kfifo_len(&port->write_fifo) || 166 (type->write_ready && !type->write_ready(port))) { 167 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 168 spin_unlock_irqrestore(&port->lock, flags); 169 return 0; 170 } 171 i = (int)find_first_bit(&port->write_urbs_free, 172 ARRAY_SIZE(port->write_urbs)); 173 spin_unlock_irqrestore(&port->lock, flags); 174 175 urb = port->write_urbs[i]; 176 count = type->prepare_write_buffer(port, urb->transfer_buffer, 177 port->bulk_out_size); 178 urb->transfer_buffer_length = count; 179 usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer); 180 spin_lock_irqsave(&port->lock, flags); 181 port->tx_bytes += count; 182 spin_unlock_irqrestore(&port->lock, flags); 183 184 clear_bit(i, &port->write_urbs_free); 185 result = usb_submit_urb(urb, mem_flags); 186 if (result) { 187 dev_err_console(port, "%s - error submitting urb: %d\n", 188 __func__, result); 189 set_bit(i, &port->write_urbs_free); 190 spin_lock_irqsave(&port->lock, flags); 191 port->tx_bytes -= count; 192 193 if (type->write_rollback) 194 type->write_rollback(port, count); 195 196 spin_unlock_irqrestore(&port->lock, flags); 197 198 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 199 return result; 200 } 201 202 goto retry; /* try sending off another urb */ 203 } 204 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start); 205 206 /** 207 * usb_serial_generic_write - generic write function 208 * @tty: tty for the port 209 * @port: usb-serial port 210 * @buf: data to write 211 * @count: number of bytes to write 212 * 213 * Return: The number of characters buffered, which may be anything from 214 * zero to @count, or a negative errno value. 215 */ 216 int usb_serial_generic_write(struct tty_struct *tty, 217 struct usb_serial_port *port, const unsigned char *buf, int count) 218 { 219 int result; 220 221 if (!port->bulk_out_size) 222 return -ENODEV; 223 224 if (!count) 225 return 0; 226 227 count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock); 228 result = usb_serial_generic_write_start(port, GFP_ATOMIC); 229 if (result) 230 return result; 231 232 return count; 233 } 234 EXPORT_SYMBOL_GPL(usb_serial_generic_write); 235 236 unsigned int usb_serial_generic_write_room(struct tty_struct *tty) 237 { 238 struct usb_serial_port *port = tty->driver_data; 239 unsigned long flags; 240 unsigned int room; 241 242 if (!port->bulk_out_size) 243 return 0; 244 245 spin_lock_irqsave(&port->lock, flags); 246 room = kfifo_avail(&port->write_fifo); 247 spin_unlock_irqrestore(&port->lock, flags); 248 249 dev_dbg(&port->dev, "%s - returns %u\n", __func__, room); 250 return room; 251 } 252 253 unsigned int usb_serial_generic_chars_in_buffer(struct tty_struct *tty) 254 { 255 struct usb_serial_port *port = tty->driver_data; 256 unsigned long flags; 257 unsigned int chars; 258 259 if (!port->bulk_out_size) 260 return 0; 261 262 spin_lock_irqsave(&port->lock, flags); 263 chars = kfifo_len(&port->write_fifo) + port->tx_bytes; 264 spin_unlock_irqrestore(&port->lock, flags); 265 266 dev_dbg(&port->dev, "%s - returns %u\n", __func__, chars); 267 return chars; 268 } 269 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer); 270 271 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout) 272 { 273 struct usb_serial_port *port = tty->driver_data; 274 struct tty_port *tport = &port->port; 275 unsigned int bps; 276 unsigned long period; 277 unsigned long expire; 278 279 bps = tty_get_baud_rate(tty); 280 if (!bps) 281 bps = 9600; /* B0 */ 282 /* 283 * Use a poll-period of roughly the time it takes to send one 284 * character or at least one jiffy. 285 */ 286 period = max_t(unsigned long, (10 * HZ / bps), 1); 287 if (timeout) 288 period = min_t(unsigned long, period, timeout); 289 290 dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n", 291 __func__, jiffies_to_msecs(timeout), 292 jiffies_to_msecs(period)); 293 expire = jiffies + timeout; 294 for (;;) { 295 mutex_lock(&tport->mutex); 296 if (tty_io_error(tty) || port->serial->type->tx_empty(port)) { 297 mutex_unlock(&tport->mutex); 298 break; 299 } 300 mutex_unlock(&tport->mutex); 301 302 schedule_timeout_interruptible(period); 303 if (signal_pending(current)) 304 break; 305 if (timeout && time_after(jiffies, expire)) 306 break; 307 } 308 } 309 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent); 310 311 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port, 312 int index, gfp_t mem_flags) 313 { 314 int res; 315 316 if (!test_and_clear_bit(index, &port->read_urbs_free)) 317 return 0; 318 319 dev_dbg(&port->dev, "%s - urb %d\n", __func__, index); 320 321 res = usb_submit_urb(port->read_urbs[index], mem_flags); 322 if (res) { 323 if (res != -EPERM && res != -ENODEV) { 324 dev_err(&port->dev, 325 "%s - usb_submit_urb failed: %d\n", 326 __func__, res); 327 } 328 set_bit(index, &port->read_urbs_free); 329 return res; 330 } 331 332 return 0; 333 } 334 335 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port, 336 gfp_t mem_flags) 337 { 338 int res; 339 int i; 340 341 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 342 res = usb_serial_generic_submit_read_urb(port, i, mem_flags); 343 if (res) 344 goto err; 345 } 346 347 return 0; 348 err: 349 for (; i >= 0; --i) 350 usb_kill_urb(port->read_urbs[i]); 351 352 return res; 353 } 354 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs); 355 356 void usb_serial_generic_process_read_urb(struct urb *urb) 357 { 358 struct usb_serial_port *port = urb->context; 359 char *ch = urb->transfer_buffer; 360 int i; 361 362 if (!urb->actual_length) 363 return; 364 /* 365 * The per character mucking around with sysrq path it too slow for 366 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of 367 * cases where the USB serial is not a console anyway. 368 */ 369 if (port->sysrq) { 370 for (i = 0; i < urb->actual_length; i++, ch++) { 371 if (!usb_serial_handle_sysrq_char(port, *ch)) 372 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL); 373 } 374 } else { 375 tty_insert_flip_string(&port->port, ch, urb->actual_length); 376 } 377 tty_flip_buffer_push(&port->port); 378 } 379 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb); 380 381 void usb_serial_generic_read_bulk_callback(struct urb *urb) 382 { 383 struct usb_serial_port *port = urb->context; 384 unsigned char *data = urb->transfer_buffer; 385 bool stopped = false; 386 int status = urb->status; 387 int i; 388 389 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 390 if (urb == port->read_urbs[i]) 391 break; 392 } 393 394 dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i, 395 urb->actual_length); 396 switch (status) { 397 case 0: 398 usb_serial_debug_data(&port->dev, __func__, urb->actual_length, 399 data); 400 port->serial->type->process_read_urb(urb); 401 break; 402 case -ENOENT: 403 case -ECONNRESET: 404 case -ESHUTDOWN: 405 dev_dbg(&port->dev, "%s - urb stopped: %d\n", 406 __func__, status); 407 stopped = true; 408 break; 409 case -EPIPE: 410 dev_err(&port->dev, "%s - urb stopped: %d\n", 411 __func__, status); 412 stopped = true; 413 break; 414 default: 415 dev_dbg(&port->dev, "%s - nonzero urb status: %d\n", 416 __func__, status); 417 break; 418 } 419 420 /* 421 * Make sure URB processing is done before marking as free to avoid 422 * racing with unthrottle() on another CPU. Matches the barriers 423 * implied by the test_and_clear_bit() in 424 * usb_serial_generic_submit_read_urb(). 425 */ 426 smp_mb__before_atomic(); 427 set_bit(i, &port->read_urbs_free); 428 /* 429 * Make sure URB is marked as free before checking the throttled flag 430 * to avoid racing with unthrottle() on another CPU. Matches the 431 * smp_mb__after_atomic() in unthrottle(). 432 */ 433 smp_mb__after_atomic(); 434 435 if (stopped) 436 return; 437 438 if (test_bit(USB_SERIAL_THROTTLED, &port->flags)) 439 return; 440 441 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC); 442 } 443 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback); 444 445 void usb_serial_generic_write_bulk_callback(struct urb *urb) 446 { 447 unsigned long flags; 448 struct usb_serial_port *port = urb->context; 449 int status = urb->status; 450 int i; 451 452 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) { 453 if (port->write_urbs[i] == urb) 454 break; 455 } 456 spin_lock_irqsave(&port->lock, flags); 457 port->tx_bytes -= urb->transfer_buffer_length; 458 set_bit(i, &port->write_urbs_free); 459 spin_unlock_irqrestore(&port->lock, flags); 460 461 switch (status) { 462 case 0: 463 break; 464 case -ENOENT: 465 case -ECONNRESET: 466 case -ESHUTDOWN: 467 dev_dbg(&port->dev, "%s - urb stopped: %d\n", 468 __func__, status); 469 return; 470 case -EPIPE: 471 dev_err_console(port, "%s - urb stopped: %d\n", 472 __func__, status); 473 return; 474 default: 475 dev_err_console(port, "%s - nonzero urb status: %d\n", 476 __func__, status); 477 break; 478 } 479 480 usb_serial_generic_write_start(port, GFP_ATOMIC); 481 usb_serial_port_softint(port); 482 } 483 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback); 484 485 void usb_serial_generic_throttle(struct tty_struct *tty) 486 { 487 struct usb_serial_port *port = tty->driver_data; 488 489 set_bit(USB_SERIAL_THROTTLED, &port->flags); 490 } 491 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle); 492 493 void usb_serial_generic_unthrottle(struct tty_struct *tty) 494 { 495 struct usb_serial_port *port = tty->driver_data; 496 497 clear_bit(USB_SERIAL_THROTTLED, &port->flags); 498 499 /* 500 * Matches the smp_mb__after_atomic() in 501 * usb_serial_generic_read_bulk_callback(). 502 */ 503 smp_mb__after_atomic(); 504 505 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 506 } 507 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle); 508 509 static bool usb_serial_generic_msr_changed(struct tty_struct *tty, 510 unsigned long arg, struct async_icount *cprev) 511 { 512 struct usb_serial_port *port = tty->driver_data; 513 struct async_icount cnow; 514 unsigned long flags; 515 bool ret; 516 517 /* 518 * Use tty-port initialised flag to detect all hangups including the 519 * one generated at USB-device disconnect. 520 */ 521 if (!tty_port_initialized(&port->port)) 522 return true; 523 524 spin_lock_irqsave(&port->lock, flags); 525 cnow = port->icount; /* atomic copy*/ 526 spin_unlock_irqrestore(&port->lock, flags); 527 528 ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) || 529 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) || 530 ((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) || 531 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts)); 532 533 *cprev = cnow; 534 535 return ret; 536 } 537 538 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg) 539 { 540 struct usb_serial_port *port = tty->driver_data; 541 struct async_icount cnow; 542 unsigned long flags; 543 int ret; 544 545 spin_lock_irqsave(&port->lock, flags); 546 cnow = port->icount; /* atomic copy */ 547 spin_unlock_irqrestore(&port->lock, flags); 548 549 ret = wait_event_interruptible(port->port.delta_msr_wait, 550 usb_serial_generic_msr_changed(tty, arg, &cnow)); 551 if (!ret && !tty_port_initialized(&port->port)) 552 ret = -EIO; 553 554 return ret; 555 } 556 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait); 557 558 int usb_serial_generic_get_icount(struct tty_struct *tty, 559 struct serial_icounter_struct *icount) 560 { 561 struct usb_serial_port *port = tty->driver_data; 562 struct async_icount cnow; 563 unsigned long flags; 564 565 spin_lock_irqsave(&port->lock, flags); 566 cnow = port->icount; /* atomic copy */ 567 spin_unlock_irqrestore(&port->lock, flags); 568 569 icount->cts = cnow.cts; 570 icount->dsr = cnow.dsr; 571 icount->rng = cnow.rng; 572 icount->dcd = cnow.dcd; 573 icount->tx = cnow.tx; 574 icount->rx = cnow.rx; 575 icount->frame = cnow.frame; 576 icount->parity = cnow.parity; 577 icount->overrun = cnow.overrun; 578 icount->brk = cnow.brk; 579 icount->buf_overrun = cnow.buf_overrun; 580 581 return 0; 582 } 583 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount); 584 585 #if defined(CONFIG_USB_SERIAL_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) 586 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 587 { 588 if (port->sysrq) { 589 if (ch && time_before(jiffies, port->sysrq)) { 590 handle_sysrq(ch); 591 port->sysrq = 0; 592 return 1; 593 } 594 port->sysrq = 0; 595 } 596 return 0; 597 } 598 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char); 599 600 int usb_serial_handle_break(struct usb_serial_port *port) 601 { 602 if (!port->port.console) 603 return 0; 604 605 if (!port->sysrq) { 606 port->sysrq = jiffies + HZ*5; 607 return 1; 608 } 609 port->sysrq = 0; 610 return 0; 611 } 612 EXPORT_SYMBOL_GPL(usb_serial_handle_break); 613 #endif 614 615 /** 616 * usb_serial_handle_dcd_change - handle a change of carrier detect state 617 * @port: usb-serial port 618 * @tty: tty for the port 619 * @status: new carrier detect status, nonzero if active 620 */ 621 void usb_serial_handle_dcd_change(struct usb_serial_port *port, 622 struct tty_struct *tty, unsigned int status) 623 { 624 dev_dbg(&port->dev, "%s - status %d\n", __func__, status); 625 626 if (tty) { 627 struct tty_ldisc *ld = tty_ldisc_ref(tty); 628 629 if (ld) { 630 if (ld->ops->dcd_change) 631 ld->ops->dcd_change(tty, status); 632 tty_ldisc_deref(ld); 633 } 634 } 635 636 if (status) 637 wake_up_interruptible(&port->port.open_wait); 638 else if (tty && !C_CLOCAL(tty)) 639 tty_hangup(tty); 640 } 641 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change); 642 643 int usb_serial_generic_resume(struct usb_serial *serial) 644 { 645 struct usb_serial_port *port; 646 int i, c = 0, r; 647 648 for (i = 0; i < serial->num_ports; i++) { 649 port = serial->port[i]; 650 if (!tty_port_initialized(&port->port)) 651 continue; 652 653 if (port->bulk_in_size) { 654 r = usb_serial_generic_submit_read_urbs(port, 655 GFP_NOIO); 656 if (r < 0) 657 c++; 658 } 659 660 if (port->bulk_out_size) { 661 r = usb_serial_generic_write_start(port, GFP_NOIO); 662 if (r < 0) 663 c++; 664 } 665 } 666 667 return c ? -EIO : 0; 668 } 669 EXPORT_SYMBOL_GPL(usb_serial_generic_resume); 670