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