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