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1 // Copyright 2014 The Chromium Authors. All rights reserved. | 1 // Copyright 2014 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 #include "device/serial/serial_io_handler_posix.h" | 5 #include "device/serial/serial_io_handler_posix.h" |
6 | 6 |
7 #include <sys/ioctl.h> | 7 #include <sys/ioctl.h> |
8 #include <termios.h> | 8 #include <termios.h> |
9 | 9 |
10 #include "base/posix/eintr_wrapper.h" | 10 #include "base/posix/eintr_wrapper.h" |
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179 | 179 |
180 bool SerialIoHandlerPosix::ConfigurePortImpl() { | 180 bool SerialIoHandlerPosix::ConfigurePortImpl() { |
181 struct termios config; | 181 struct termios config; |
182 if (tcgetattr(file().GetPlatformFile(), &config) != 0) { | 182 if (tcgetattr(file().GetPlatformFile(), &config) != 0) { |
183 VPLOG(1) << "Failed to get port attributes"; | 183 VPLOG(1) << "Failed to get port attributes"; |
184 return false; | 184 return false; |
185 } | 185 } |
186 | 186 |
187 // Set flags for 'raw' operation | 187 // Set flags for 'raw' operation |
188 config.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHONL | ISIG); | 188 config.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHONL | ISIG); |
189 config.c_iflag &= | 189 config.c_iflag &= ~(IGNBRK | BRKINT | ISTRIP | INLCR | IGNCR | ICRNL | IXON); |
190 ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | ICRNL | IXON); | 190 config.c_iflag |= PARMRK; |
191 config.c_oflag &= ~OPOST; | 191 config.c_oflag &= ~OPOST; |
192 | 192 |
193 // CLOCAL causes the system to disregard the DCD signal state. | 193 // CLOCAL causes the system to disregard the DCD signal state. |
194 // CREAD enables reading from the port. | 194 // CREAD enables reading from the port. |
195 config.c_cflag |= (CLOCAL | CREAD); | 195 config.c_cflag |= (CLOCAL | CREAD); |
196 | 196 |
197 DCHECK(options().bitrate); | 197 DCHECK(options().bitrate); |
198 speed_t bitrate_opt = B0; | 198 speed_t bitrate_opt = B0; |
199 if (BitrateToSpeedConstant(options().bitrate, &bitrate_opt)) { | 199 if (BitrateToSpeedConstant(options().bitrate, &bitrate_opt)) { |
200 cfsetispeed(&config, bitrate_opt); | 200 cfsetispeed(&config, bitrate_opt); |
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227 break; | 227 break; |
228 case serial::PARITY_BIT_ODD: | 228 case serial::PARITY_BIT_ODD: |
229 config.c_cflag |= (PARODD | PARENB); | 229 config.c_cflag |= (PARODD | PARENB); |
230 break; | 230 break; |
231 case serial::PARITY_BIT_NO: | 231 case serial::PARITY_BIT_NO: |
232 default: | 232 default: |
233 config.c_cflag &= ~(PARODD | PARENB); | 233 config.c_cflag &= ~(PARODD | PARENB); |
234 break; | 234 break; |
235 } | 235 } |
236 | 236 |
| 237 error_detect_state_ = ErrorDetectState::NO_ERROR; |
| 238 num_chars_stashed_ = 0; |
| 239 |
| 240 if (config.c_cflag & PARENB) { |
| 241 config.c_iflag &= ~IGNPAR; |
| 242 config.c_iflag |= INPCK; |
| 243 parity_check_enabled_ = true; |
| 244 } else { |
| 245 config.c_iflag |= IGNPAR; |
| 246 config.c_iflag &= ~INPCK; |
| 247 parity_check_enabled_ = false; |
| 248 } |
| 249 |
237 DCHECK(options().stop_bits != serial::STOP_BITS_NONE); | 250 DCHECK(options().stop_bits != serial::STOP_BITS_NONE); |
238 switch (options().stop_bits) { | 251 switch (options().stop_bits) { |
239 case serial::STOP_BITS_TWO: | 252 case serial::STOP_BITS_TWO: |
240 config.c_cflag |= CSTOPB; | 253 config.c_cflag |= CSTOPB; |
241 break; | 254 break; |
242 case serial::STOP_BITS_ONE: | 255 case serial::STOP_BITS_ONE: |
243 default: | 256 default: |
244 config.c_cflag &= ~CSTOPB; | 257 config.c_cflag &= ~CSTOPB; |
245 break; | 258 break; |
246 } | 259 } |
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280 pending_read_buffer_len())); | 293 pending_read_buffer_len())); |
281 if (bytes_read < 0) { | 294 if (bytes_read < 0) { |
282 if (errno == ENXIO) { | 295 if (errno == ENXIO) { |
283 ReadCompleted(0, serial::RECEIVE_ERROR_DEVICE_LOST); | 296 ReadCompleted(0, serial::RECEIVE_ERROR_DEVICE_LOST); |
284 } else { | 297 } else { |
285 ReadCompleted(0, serial::RECEIVE_ERROR_SYSTEM_ERROR); | 298 ReadCompleted(0, serial::RECEIVE_ERROR_SYSTEM_ERROR); |
286 } | 299 } |
287 } else if (bytes_read == 0) { | 300 } else if (bytes_read == 0) { |
288 ReadCompleted(0, serial::RECEIVE_ERROR_DEVICE_LOST); | 301 ReadCompleted(0, serial::RECEIVE_ERROR_DEVICE_LOST); |
289 } else { | 302 } else { |
290 ReadCompleted(bytes_read, serial::RECEIVE_ERROR_NONE); | 303 bool break_detected = false; |
| 304 bool parity_error_detected = false; |
| 305 int new_bytes_read = |
| 306 CheckReceiveError(pending_read_buffer(), pending_read_buffer_len(), |
| 307 bytes_read, break_detected, parity_error_detected); |
| 308 |
| 309 if (break_detected) { |
| 310 ReadCompleted(new_bytes_read, serial::RECEIVE_ERROR_BREAK); |
| 311 } else if (parity_error_detected) { |
| 312 ReadCompleted(new_bytes_read, serial::RECEIVE_ERROR_PARITY_ERROR); |
| 313 } else { |
| 314 ReadCompleted(new_bytes_read, serial::RECEIVE_ERROR_NONE); |
| 315 } |
291 } | 316 } |
292 } else { | 317 } else { |
293 // Stop watching the fd if we get notifications with no pending | 318 // Stop watching the fd if we get notifications with no pending |
294 // reads or writes to avoid starving the message loop. | 319 // reads or writes to avoid starving the message loop. |
295 is_watching_reads_ = false; | 320 is_watching_reads_ = false; |
296 file_read_watcher_.StopWatchingFileDescriptor(); | 321 file_read_watcher_.StopWatchingFileDescriptor(); |
297 } | 322 } |
298 } | 323 } |
299 | 324 |
300 void SerialIoHandlerPosix::OnFileCanWriteWithoutBlocking(int fd) { | 325 void SerialIoHandlerPosix::OnFileCanWriteWithoutBlocking(int fd) { |
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447 } | 472 } |
448 | 473 |
449 bool SerialIoHandlerPosix::ClearBreak() { | 474 bool SerialIoHandlerPosix::ClearBreak() { |
450 if (ioctl(file().GetPlatformFile(), TIOCCBRK, 0) != 0) { | 475 if (ioctl(file().GetPlatformFile(), TIOCCBRK, 0) != 0) { |
451 VPLOG(1) << "Failed to clear break"; | 476 VPLOG(1) << "Failed to clear break"; |
452 return false; | 477 return false; |
453 } | 478 } |
454 return true; | 479 return true; |
455 } | 480 } |
456 | 481 |
| 482 // break sequence: |
| 483 // '\377' --> ErrorDetectState::MARK_377_SEEN |
| 484 // '\0' --> ErrorDetectState::MARK_0_SEEN |
| 485 // '\0' --> break detected |
| 486 // |
| 487 // parity error sequence: |
| 488 // '\377' --> ErrorDetectState::MARK_377_SEEN |
| 489 // '\0' --> ErrorDetectState::MARK_0_SEEN |
| 490 // character with parity error --> parity error detected |
| 491 // |
| 492 // break/parity error sequences are removed from the byte stream |
| 493 // '\377' '\377' sequence is replaced with '\377' |
| 494 int SerialIoHandlerPosix::CheckReceiveError(char* buffer, |
| 495 int buffer_len, |
| 496 int bytes_read, |
| 497 bool& break_detected, |
| 498 bool& parity_error_detected) { |
| 499 int new_bytes_read = num_chars_stashed_; |
| 500 DCHECK_LE(new_bytes_read, 2); |
| 501 |
| 502 for (int i = 0; i < bytes_read; ++i) { |
| 503 char ch = buffer[i]; |
| 504 if (new_bytes_read == 0) { |
| 505 chars_stashed_[0] = ch; |
| 506 } else if (new_bytes_read == 1) { |
| 507 chars_stashed_[1] = ch; |
| 508 } else { |
| 509 buffer[new_bytes_read - 2] = ch; |
| 510 } |
| 511 ++new_bytes_read; |
| 512 switch (error_detect_state_) { |
| 513 case ErrorDetectState::NO_ERROR: |
| 514 if (ch == '\377') { |
| 515 error_detect_state_ = ErrorDetectState::MARK_377_SEEN; |
| 516 } |
| 517 break; |
| 518 case ErrorDetectState::MARK_377_SEEN: |
| 519 DCHECK_GE(new_bytes_read, 2); |
| 520 if (ch == '\0') { |
| 521 error_detect_state_ = ErrorDetectState::MARK_0_SEEN; |
| 522 } else { |
| 523 if (ch == '\377') { |
| 524 // receive two bytes '\377' '\377', since ISTRIP is not set and |
| 525 // PARMRK is set, a valid byte '\377' is passed to the program as |
| 526 // two bytes, '\377' '\377'. Replace these two bytes with one byte |
| 527 // of '\377', and set error_detect_state_ back to |
| 528 // ErrorDetectState::NO_ERROR. |
| 529 --new_bytes_read; |
| 530 } |
| 531 error_detect_state_ = ErrorDetectState::NO_ERROR; |
| 532 } |
| 533 break; |
| 534 case ErrorDetectState::MARK_0_SEEN: |
| 535 DCHECK_GE(new_bytes_read, 3); |
| 536 if (ch == '\0') { |
| 537 break_detected = true; |
| 538 new_bytes_read -= 3; |
| 539 error_detect_state_ = ErrorDetectState::NO_ERROR; |
| 540 } else { |
| 541 if (parity_check_enabled_) { |
| 542 parity_error_detected = true; |
| 543 new_bytes_read -= 3; |
| 544 error_detect_state_ = ErrorDetectState::NO_ERROR; |
| 545 } else if (ch == '\377') { |
| 546 error_detect_state_ = ErrorDetectState::MARK_377_SEEN; |
| 547 } else { |
| 548 error_detect_state_ = ErrorDetectState::NO_ERROR; |
| 549 } |
| 550 } |
| 551 break; |
| 552 } |
| 553 } |
| 554 // Now new_bytes_read bytes should be returned to the caller (including the |
| 555 // previously stashed characters that were stored at chars_stashed_[]) and are |
| 556 // now stored at: chars_stashed_[0], chars_stashed_[1], buffer[...]. |
| 557 |
| 558 // Stash up to 2 characters that are potentially part of a break/parity error |
| 559 // sequence. The buffer may also not be large enough to store all the bytes. |
| 560 // tmp[] stores the characters that need to be stashed for this read. |
| 561 char tmp[2]; |
| 562 num_chars_stashed_ = 0; |
| 563 if (error_detect_state_ == ErrorDetectState::MARK_0_SEEN || |
| 564 new_bytes_read - buffer_len == 2) { |
| 565 // need to stash the last two characters |
| 566 if (new_bytes_read == 2) { |
| 567 memcpy(tmp, chars_stashed_, new_bytes_read); |
| 568 } else { |
| 569 if (new_bytes_read == 3) { |
| 570 tmp[0] = chars_stashed_[1]; |
| 571 } else { |
| 572 tmp[0] = buffer[new_bytes_read - 4]; |
| 573 } |
| 574 tmp[1] = buffer[new_bytes_read - 3]; |
| 575 } |
| 576 num_chars_stashed_ = 2; |
| 577 } else if (error_detect_state_ == ErrorDetectState::MARK_377_SEEN || |
| 578 new_bytes_read - buffer_len == 1) { |
| 579 // need to stash the last character |
| 580 if (new_bytes_read <= 2) { |
| 581 tmp[0] = chars_stashed_[new_bytes_read - 1]; |
| 582 } else { |
| 583 tmp[0] = buffer[new_bytes_read - 3]; |
| 584 } |
| 585 num_chars_stashed_ = 1; |
| 586 } |
| 587 |
| 588 new_bytes_read -= num_chars_stashed_; |
| 589 if (new_bytes_read > 2) { |
| 590 // right shift two bytes to store bytes from chars_stashed_[] |
| 591 memmove(buffer + 2, buffer, new_bytes_read - 2); |
| 592 } |
| 593 memcpy(buffer, chars_stashed_, std::min(new_bytes_read, 2)); |
| 594 memcpy(chars_stashed_, tmp, num_chars_stashed_); |
| 595 return new_bytes_read; |
| 596 } |
| 597 |
457 std::string SerialIoHandler::MaybeFixUpPortName(const std::string& port_name) { | 598 std::string SerialIoHandler::MaybeFixUpPortName(const std::string& port_name) { |
458 return port_name; | 599 return port_name; |
459 } | 600 } |
460 | 601 |
461 } // namespace device | 602 } // namespace device |
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