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 * Try sending off another urb, unless called from completion handler 178 * (in which case there will be no free urb or no data). 179 */ 180 if (mem_flags != GFP_ATOMIC) 181 goto retry; 182 183 clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags); 184 185 return 0; 186 } 187 EXPORT_SYMBOL_GPL(usb_serial_generic_write_start); 188 189 /** 190 * usb_serial_generic_write - generic write function 191 * @tty: tty for the port 192 * @port: usb-serial port 193 * @buf: data to write 194 * @count: number of bytes to write 195 * 196 * Return: The number of characters buffered, which may be anything from 197 * zero to @count, or a negative errno value. 198 */ 199 int usb_serial_generic_write(struct tty_struct *tty, 200 struct usb_serial_port *port, const unsigned char *buf, int count) 201 { 202 int result; 203 204 if (!port->bulk_out_size) 205 return -ENODEV; 206 207 if (!count) 208 return 0; 209 210 count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock); 211 result = usb_serial_generic_write_start(port, GFP_KERNEL); 212 if (result) 213 return result; 214 215 return count; 216 } 217 EXPORT_SYMBOL_GPL(usb_serial_generic_write); 218 219 int usb_serial_generic_write_room(struct tty_struct *tty) 220 { 221 struct usb_serial_port *port = tty->driver_data; 222 unsigned long flags; 223 int room; 224 225 if (!port->bulk_out_size) 226 return 0; 227 228 spin_lock_irqsave(&port->lock, flags); 229 room = kfifo_avail(&port->write_fifo); 230 spin_unlock_irqrestore(&port->lock, flags); 231 232 dev_dbg(&port->dev, "%s - returns %d\n", __func__, room); 233 return room; 234 } 235 236 int usb_serial_generic_chars_in_buffer(struct tty_struct *tty) 237 { 238 struct usb_serial_port *port = tty->driver_data; 239 unsigned long flags; 240 int chars; 241 242 if (!port->bulk_out_size) 243 return 0; 244 245 spin_lock_irqsave(&port->lock, flags); 246 chars = kfifo_len(&port->write_fifo) + port->tx_bytes; 247 spin_unlock_irqrestore(&port->lock, flags); 248 249 dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars); 250 return chars; 251 } 252 EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer); 253 254 void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout) 255 { 256 struct usb_serial_port *port = tty->driver_data; 257 unsigned int bps; 258 unsigned long period; 259 unsigned long expire; 260 261 bps = tty_get_baud_rate(tty); 262 if (!bps) 263 bps = 9600; /* B0 */ 264 /* 265 * Use a poll-period of roughly the time it takes to send one 266 * character or at least one jiffy. 267 */ 268 period = max_t(unsigned long, (10 * HZ / bps), 1); 269 period = min_t(unsigned long, period, timeout); 270 271 dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n", 272 __func__, jiffies_to_msecs(timeout), 273 jiffies_to_msecs(period)); 274 expire = jiffies + timeout; 275 while (!port->serial->type->tx_empty(port)) { 276 schedule_timeout_interruptible(period); 277 if (signal_pending(current)) 278 break; 279 if (time_after(jiffies, expire)) 280 break; 281 } 282 } 283 EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent); 284 285 static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port, 286 int index, gfp_t mem_flags) 287 { 288 int res; 289 290 if (!test_and_clear_bit(index, &port->read_urbs_free)) 291 return 0; 292 293 dev_dbg(&port->dev, "%s - urb %d\n", __func__, index); 294 295 res = usb_submit_urb(port->read_urbs[index], mem_flags); 296 if (res) { 297 if (res != -EPERM) { 298 dev_err(&port->dev, 299 "%s - usb_submit_urb failed: %d\n", 300 __func__, res); 301 } 302 set_bit(index, &port->read_urbs_free); 303 return res; 304 } 305 306 return 0; 307 } 308 309 int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port, 310 gfp_t mem_flags) 311 { 312 int res; 313 int i; 314 315 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 316 res = usb_serial_generic_submit_read_urb(port, i, mem_flags); 317 if (res) 318 goto err; 319 } 320 321 return 0; 322 err: 323 for (; i >= 0; --i) 324 usb_kill_urb(port->read_urbs[i]); 325 326 return res; 327 } 328 EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs); 329 330 void usb_serial_generic_process_read_urb(struct urb *urb) 331 { 332 struct usb_serial_port *port = urb->context; 333 char *ch = (char *)urb->transfer_buffer; 334 int i; 335 336 if (!urb->actual_length) 337 return; 338 /* 339 * The per character mucking around with sysrq path it too slow for 340 * stuff like 3G modems, so shortcircuit it in the 99.9999999% of 341 * cases where the USB serial is not a console anyway. 342 */ 343 if (!port->port.console || !port->sysrq) 344 tty_insert_flip_string(&port->port, ch, urb->actual_length); 345 else { 346 for (i = 0; i < urb->actual_length; i++, ch++) { 347 if (!usb_serial_handle_sysrq_char(port, *ch)) 348 tty_insert_flip_char(&port->port, *ch, TTY_NORMAL); 349 } 350 } 351 tty_flip_buffer_push(&port->port); 352 } 353 EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb); 354 355 void usb_serial_generic_read_bulk_callback(struct urb *urb) 356 { 357 struct usb_serial_port *port = urb->context; 358 unsigned char *data = urb->transfer_buffer; 359 unsigned long flags; 360 int i; 361 362 for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) { 363 if (urb == port->read_urbs[i]) 364 break; 365 } 366 set_bit(i, &port->read_urbs_free); 367 368 dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i, 369 urb->actual_length); 370 371 if (urb->status) { 372 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n", 373 __func__, urb->status); 374 return; 375 } 376 377 usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data); 378 port->serial->type->process_read_urb(urb); 379 380 /* Throttle the device if requested by tty */ 381 spin_lock_irqsave(&port->lock, flags); 382 port->throttled = port->throttle_req; 383 if (!port->throttled) { 384 spin_unlock_irqrestore(&port->lock, flags); 385 usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC); 386 } else 387 spin_unlock_irqrestore(&port->lock, flags); 388 } 389 EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback); 390 391 void usb_serial_generic_write_bulk_callback(struct urb *urb) 392 { 393 unsigned long flags; 394 struct usb_serial_port *port = urb->context; 395 int status = urb->status; 396 int i; 397 398 for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i) 399 if (port->write_urbs[i] == urb) 400 break; 401 402 spin_lock_irqsave(&port->lock, flags); 403 port->tx_bytes -= urb->transfer_buffer_length; 404 set_bit(i, &port->write_urbs_free); 405 spin_unlock_irqrestore(&port->lock, flags); 406 407 if (status) { 408 dev_dbg(&port->dev, "%s - non-zero urb status: %d\n", 409 __func__, status); 410 411 spin_lock_irqsave(&port->lock, flags); 412 kfifo_reset_out(&port->write_fifo); 413 spin_unlock_irqrestore(&port->lock, flags); 414 } else { 415 usb_serial_generic_write_start(port, GFP_ATOMIC); 416 } 417 418 usb_serial_port_softint(port); 419 } 420 EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback); 421 422 void usb_serial_generic_throttle(struct tty_struct *tty) 423 { 424 struct usb_serial_port *port = tty->driver_data; 425 unsigned long flags; 426 427 spin_lock_irqsave(&port->lock, flags); 428 port->throttle_req = 1; 429 spin_unlock_irqrestore(&port->lock, flags); 430 } 431 EXPORT_SYMBOL_GPL(usb_serial_generic_throttle); 432 433 void usb_serial_generic_unthrottle(struct tty_struct *tty) 434 { 435 struct usb_serial_port *port = tty->driver_data; 436 int was_throttled; 437 438 spin_lock_irq(&port->lock); 439 was_throttled = port->throttled; 440 port->throttled = port->throttle_req = 0; 441 spin_unlock_irq(&port->lock); 442 443 if (was_throttled) 444 usb_serial_generic_submit_read_urbs(port, GFP_KERNEL); 445 } 446 EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle); 447 448 static bool usb_serial_generic_msr_changed(struct tty_struct *tty, 449 unsigned long arg, struct async_icount *cprev) 450 { 451 struct usb_serial_port *port = tty->driver_data; 452 struct async_icount cnow; 453 unsigned long flags; 454 bool ret; 455 456 /* 457 * Use tty-port initialised flag to detect all hangups including the 458 * one generated at USB-device disconnect. 459 */ 460 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) 461 return true; 462 463 spin_lock_irqsave(&port->lock, flags); 464 cnow = port->icount; /* atomic copy*/ 465 spin_unlock_irqrestore(&port->lock, flags); 466 467 ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) || 468 ((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) || 469 ((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) || 470 ((arg & TIOCM_CTS) && (cnow.cts != cprev->cts)); 471 472 *cprev = cnow; 473 474 return ret; 475 } 476 477 int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg) 478 { 479 struct usb_serial_port *port = tty->driver_data; 480 struct async_icount cnow; 481 unsigned long flags; 482 int ret; 483 484 spin_lock_irqsave(&port->lock, flags); 485 cnow = port->icount; /* atomic copy */ 486 spin_unlock_irqrestore(&port->lock, flags); 487 488 ret = wait_event_interruptible(port->port.delta_msr_wait, 489 usb_serial_generic_msr_changed(tty, arg, &cnow)); 490 if (!ret && !test_bit(ASYNCB_INITIALIZED, &port->port.flags)) 491 ret = -EIO; 492 493 return ret; 494 } 495 EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait); 496 497 int usb_serial_generic_get_icount(struct tty_struct *tty, 498 struct serial_icounter_struct *icount) 499 { 500 struct usb_serial_port *port = tty->driver_data; 501 struct async_icount cnow; 502 unsigned long flags; 503 504 spin_lock_irqsave(&port->lock, flags); 505 cnow = port->icount; /* atomic copy */ 506 spin_unlock_irqrestore(&port->lock, flags); 507 508 icount->cts = cnow.cts; 509 icount->dsr = cnow.dsr; 510 icount->rng = cnow.rng; 511 icount->dcd = cnow.dcd; 512 icount->tx = cnow.tx; 513 icount->rx = cnow.rx; 514 icount->frame = cnow.frame; 515 icount->parity = cnow.parity; 516 icount->overrun = cnow.overrun; 517 icount->brk = cnow.brk; 518 icount->buf_overrun = cnow.buf_overrun; 519 520 return 0; 521 } 522 EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount); 523 524 #ifdef CONFIG_MAGIC_SYSRQ 525 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 526 { 527 if (port->sysrq && port->port.console) { 528 if (ch && time_before(jiffies, port->sysrq)) { 529 handle_sysrq(ch); 530 port->sysrq = 0; 531 return 1; 532 } 533 port->sysrq = 0; 534 } 535 return 0; 536 } 537 #else 538 int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch) 539 { 540 return 0; 541 } 542 #endif 543 EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char); 544 545 int usb_serial_handle_break(struct usb_serial_port *port) 546 { 547 if (!port->sysrq) { 548 port->sysrq = jiffies + HZ*5; 549 return 1; 550 } 551 port->sysrq = 0; 552 return 0; 553 } 554 EXPORT_SYMBOL_GPL(usb_serial_handle_break); 555 556 /** 557 * usb_serial_handle_dcd_change - handle a change of carrier detect state 558 * @port: usb-serial port 559 * @tty: tty for the port 560 * @status: new carrier detect status, nonzero if active 561 */ 562 void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port, 563 struct tty_struct *tty, unsigned int status) 564 { 565 struct tty_port *port = &usb_port->port; 566 567 dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status); 568 569 if (tty) { 570 struct tty_ldisc *ld = tty_ldisc_ref(tty); 571 572 if (ld) { 573 if (ld->ops->dcd_change) 574 ld->ops->dcd_change(tty, status); 575 tty_ldisc_deref(ld); 576 } 577 } 578 579 if (status) 580 wake_up_interruptible(&port->open_wait); 581 else if (tty && !C_CLOCAL(tty)) 582 tty_hangup(tty); 583 } 584 EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change); 585 586 int usb_serial_generic_resume(struct usb_serial *serial) 587 { 588 struct usb_serial_port *port; 589 int i, c = 0, r; 590 591 for (i = 0; i < serial->num_ports; i++) { 592 port = serial->port[i]; 593 if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags)) 594 continue; 595 596 if (port->bulk_in_size) { 597 r = usb_serial_generic_submit_read_urbs(port, 598 GFP_NOIO); 599 if (r < 0) 600 c++; 601 } 602 603 if (port->bulk_out_size) { 604 r = usb_serial_generic_write_start(port, GFP_NOIO); 605 if (r < 0) 606 c++; 607 } 608 } 609 610 return c ? -EIO : 0; 611 } 612 EXPORT_SYMBOL_GPL(usb_serial_generic_resume); 613