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); 632