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serial-dmm: Add Voltcraft VC-840 (UT-D02) support.
[libsigrok.git] / hardware / common / serial.c
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1/*
2 * This file is part of the sigrok project.
3 *
4 * Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
5 * Copyright (C) 2010-2012 Uwe Hermann <uwe@hermann-uwe.de>
6 * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
7 *
8 * This program is free software: you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or
11 * (at your option) any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22#include <string.h>
23#include <sys/types.h>
24#include <sys/stat.h>
25#include <fcntl.h>
26#include <unistd.h>
27#ifdef _WIN32
28#include <windows.h>
29#else
30#include <glob.h>
31#include <termios.h>
32#include <sys/ioctl.h>
33#endif
34#include <stdlib.h>
35#include <errno.h>
36#include <glib.h>
37#include "libsigrok.h"
38#include "libsigrok-internal.h"
39
40/* Message logging helpers with driver-specific prefix string. */
41#define DRIVER_LOG_DOMAIN "serial: "
42#define sr_log(l, s, args...) sr_log(l, DRIVER_LOG_DOMAIN s, ## args)
43#define sr_spew(s, args...) sr_spew(DRIVER_LOG_DOMAIN s, ## args)
44#define sr_dbg(s, args...) sr_dbg(DRIVER_LOG_DOMAIN s, ## args)
45#define sr_info(s, args...) sr_info(DRIVER_LOG_DOMAIN s, ## args)
46#define sr_warn(s, args...) sr_warn(DRIVER_LOG_DOMAIN s, ## args)
47#define sr_err(s, args...) sr_err(DRIVER_LOG_DOMAIN s, ## args)
48
49// FIXME: Must be moved, or rather passed as function argument.
50#ifdef _WIN32
51static HANDLE hdl;
52#endif
53
54/**
55 * Open the specified serial port.
56 *
57 * @param serial Previously initialized serial port structure.
58 * @param flags Flags to use when opening the serial port. Possible flags
59 * include SERIAL_RDWR, SERIAL_RDONLY, SERIAL_NONBLOCK.
60 *
61 * If the serial structure contains a serialcomm string, it will be
62 * passed to serial_set_paramstr() after the port is opened.
63 *
64 * @return SR_OK on success, SR_ERR on failure.
65 */
66SR_PRIV int serial_open(struct sr_serial_dev_inst *serial, int flags)
67{
68 int flags_local = 0;
69#ifdef _WIN32
70 DWORD desired_access = 0, flags_and_attributes = 0;
71#endif
72
73 if (!serial) {
74 sr_dbg("Invalid serial port.");
75 return SR_ERR;
76 }
77
78 sr_spew("Opening serial port '%s' (flags %d).", serial->port, flags);
79
80#ifdef _WIN32
81 /* Map 'flags' to the OS-specific settings. */
82 desired_access |= GENERIC_READ;
83 flags_and_attributes = FILE_ATTRIBUTE_NORMAL;
84 if (flags & SERIAL_RDWR)
85 desired_access |= GENERIC_WRITE;
86 if (flags & SERIAL_NONBLOCK)
87 flags_and_attributes |= FILE_FLAG_OVERLAPPED;
88
89 hdl = CreateFile(serial->port, desired_access, 0, 0,
90 OPEN_EXISTING, flags_and_attributes, 0);
91 if (hdl == INVALID_HANDLE_VALUE) {
92 sr_err("Error opening serial port '%s'.", serial->port);
93 return SR_ERR;
94 }
95#else
96 /* Map 'flags' to the OS-specific settings. */
97 if (flags & SERIAL_RDWR)
98 flags_local |= O_RDWR;
99 if (flags & SERIAL_RDONLY)
100 flags_local |= O_RDONLY;
101 if (flags & SERIAL_NONBLOCK)
102 flags_local |= O_NONBLOCK;
103
104 if ((serial->fd = open(serial->port, flags_local)) < 0) {
105 sr_err("Error opening serial port '%s': %s.", serial->port,
106 strerror(errno));
107 return SR_ERR;
108 }
109
110 sr_spew("Opened serial port '%s' (fd %d).", serial->port, serial->fd);
111#endif
112
113 if (serial->serialcomm)
114 return serial_set_paramstr(serial, serial->serialcomm);
115 else
116 return SR_OK;
117}
118
119/**
120 * Close the specified serial port.
121 *
122 * @param serial Previously initialized serial port structure.
123 *
124 * @return SR_OK on success, SR_ERR on failure.
125 */
126SR_PRIV int serial_close(struct sr_serial_dev_inst *serial)
127{
128 int ret;
129
130 if (!serial) {
131 sr_dbg("Invalid serial port.");
132 return SR_ERR;
133 }
134
135 if (serial->fd == -1) {
136 sr_dbg("Cannot close unopened serial port %s (fd %d).",
137 serial->port, serial->fd);
138 return SR_ERR;
139 }
140
141 sr_spew("Closing serial port %s (fd %d).", serial->port, serial->fd);
142 ret = SR_OK;
143
144#ifdef _WIN32
145 /* Returns non-zero upon success, 0 upon failure. */
146 if (CloseHandle(hdl) == 0)
147 ret = SR_ERR;
148#else
149 /* Returns 0 upon success, -1 upon failure. */
150 if (close(serial->fd) < 0) {
151 sr_err("Error closing serial port: %s (fd %d).", strerror(errno),
152 serial->fd);
153 ret = SR_ERR;
154 }
155#endif
156
157 serial->fd = -1;
158
159 return ret;
160}
161
162/**
163 * Flush serial port buffers.
164 *
165 * @param serial Previously initialized serial port structure.
166 *
167 * @return SR_OK on success, SR_ERR on failure.
168 */
169SR_PRIV int serial_flush(struct sr_serial_dev_inst *serial)
170{
171 int ret;
172
173 if (!serial) {
174 sr_dbg("Invalid serial port.");
175 return SR_ERR;
176 }
177
178 if (serial->fd == -1) {
179 sr_dbg("Cannot flush unopened serial port %s (fd %d).",
180 serial->port, serial->fd);
181 return SR_ERR;
182 }
183
184 sr_spew("Flushing serial port %s (fd %d).", serial->port, serial->fd);
185 ret = SR_OK;
186
187#ifdef _WIN32
188 /* Returns non-zero upon success, 0 upon failure. */
189 if (PurgeComm(hdl, PURGE_RXCLEAR | PURGE_TXCLEAR) == 0) {
190 sr_err("Error flushing serial port: %s.", strerror(errno));
191 ret = SR_ERR;
192 }
193#else
194 /* Returns 0 upon success, -1 upon failure. */
195 if (tcflush(serial->fd, TCIOFLUSH) < 0) {
196 sr_err("Error flushing serial port: %s.", strerror(errno));
197 ret = SR_ERR;
198 }
199
200 return ret;
201#endif
202}
203
204/**
205 * Write a number of bytes to the specified serial port.
206 *
207 * @param serial Previously initialized serial port structure.
208 * @param buf Buffer containing the bytes to write.
209 * @param count Number of bytes to write.
210 *
211 * @return The number of bytes written, or -1 upon failure.
212 */
213SR_PRIV int serial_write(struct sr_serial_dev_inst *serial,
214 const void *buf, size_t count)
215{
216 ssize_t ret;
217
218 if (!serial) {
219 sr_dbg("Invalid serial port.");
220 return -1;
221 }
222
223 if (serial->fd == -1) {
224 sr_dbg("Cannot use unopened serial port %s (fd %d).",
225 serial->port, serial->fd);
226 return -1;
227 }
228
229#ifdef _WIN32
230 DWORD tmp = 0;
231
232 /* FIXME */
233 /* Returns non-zero upon success, 0 upon failure. */
234 WriteFile(hdl, buf, count, &tmp, NULL);
235#else
236 /* Returns the number of bytes written, or -1 upon failure. */
237 ret = write(serial->fd, buf, count);
238 if (ret < 0)
239 sr_err("Write error: %s.", strerror(errno));
240 else
241 sr_spew("Wrote %d/%d bytes (fd %d).", ret, count, serial->fd);
242#endif
243
244 return ret;
245}
246
247/**
248 * Read a number of bytes from the specified serial port.
249 *
250 * @param serial Previously initialized serial port structure.
251 * @param buf Buffer where to store the bytes that are read.
252 * @param count The number of bytes to read.
253 *
254 * @return The number of bytes read, or -1 upon failure.
255 */
256SR_PRIV int serial_read(struct sr_serial_dev_inst *serial, void *buf,
257 size_t count)
258{
259 ssize_t ret;
260
261 if (!serial) {
262 sr_dbg("Invalid serial port.");
263 return -1;
264 }
265
266 if (serial->fd == -1) {
267 sr_dbg("Cannot use unopened serial port %s (fd %d).",
268 serial->port, serial->fd);
269 return -1;
270 }
271
272#ifdef _WIN32
273 DWORD tmp = 0;
274
275 /* FIXME */
276 /* Returns non-zero upon success, 0 upon failure. */
277 return ReadFile(hdl, buf, count, &tmp, NULL);
278#else
279 /* Returns the number of bytes read, or -1 upon failure. */
280 ret = read(serial->fd, buf, count);
281 if (ret < 0)
282 /*
283 * Should be sr_err(), but that would yield lots of
284 * "Resource temporarily unavailable" messages.
285 */
286 sr_spew("Read error: %s (fd %d).", strerror(errno), serial->fd);
287 else
288 sr_spew("Read %d/%d bytes (fd %d).", ret, count, serial->fd);
289#endif
290
291 return ret;
292}
293
294/**
295 * Set serial parameters for the specified serial port.
296 *
297 * @param serial Previously initialized serial port structure.
298 * @param baudrate The baudrate to set.
299 * @param bits The number of data bits to use.
300 * @param parity The parity setting to use (0 = none, 1 = even, 2 = odd).
301 * @param stopbits The number of stop bits to use (1 or 2).
302 * @param flowcontrol The flow control settings to use (0 = none, 1 = RTS/CTS,
303 * 2 = XON/XOFF).
304 *
305 * @return SR_OK upon success, SR_ERR upon failure.
306 */
307SR_PRIV int serial_set_params(struct sr_serial_dev_inst *serial, int baudrate,
308 int bits, int parity, int stopbits,
309 int flowcontrol, int rts, int dtr)
310{
311 if (!serial) {
312 sr_dbg("Invalid serial port.");
313 return SR_ERR;
314 }
315
316 if (serial->fd == -1) {
317 sr_dbg("Cannot configure unopened serial port %s (fd %d).",
318 serial->port, serial->fd);
319 return SR_ERR;
320 }
321
322 sr_spew("Setting serial parameters on port %s (fd %d).", serial->port,
323 serial->fd);
324
325#ifdef _WIN32
326 DCB dcb;
327
328 if (!GetCommState(hdl, &dcb)) {
329 sr_err("Failed to get comm state on port %s (fd %d): %d.",
330 serial->port, serial->fd, GetLastError());
331 return SR_ERR;
332 }
333
334 switch (baudrate) {
335 /*
336 * The baudrates 50/75/134/150/200/1800/230400/460800 do not seem to
337 * have documented CBR_* macros.
338 */
339 case 110:
340 dcb.BaudRate = CBR_110;
341 break;
342 case 300:
343 dcb.BaudRate = CBR_300;
344 break;
345 case 600:
346 dcb.BaudRate = CBR_600;
347 break;
348 case 1200:
349 dcb.BaudRate = CBR_1200;
350 break;
351 case 2400:
352 dcb.BaudRate = CBR_2400;
353 break;
354 case 4800:
355 dcb.BaudRate = CBR_4800;
356 break;
357 case 9600:
358 dcb.BaudRate = CBR_9600;
359 break;
360 case 14400:
361 dcb.BaudRate = CBR_14400; /* Not available on Unix? */
362 break;
363 case 19200:
364 dcb.BaudRate = CBR_19200;
365 break;
366 case 38400:
367 dcb.BaudRate = CBR_38400;
368 break;
369 case 57600:
370 dcb.BaudRate = CBR_57600;
371 break;
372 case 115200:
373 dcb.BaudRate = CBR_115200;
374 break;
375 case 128000:
376 dcb.BaudRate = CBR_128000; /* Not available on Unix? */
377 break;
378 case 256000:
379 dcb.BaudRate = CBR_256000; /* Not available on Unix? */
380 break;
381 default:
382 sr_err("Unsupported baudrate: %d.", baudrate);
383 return SR_ERR;
384 }
385 sr_spew("Configuring baudrate to %d (%d).", baudrate, dcb.BaudRate);
386
387 sr_spew("Configuring %d data bits.", bits);
388 dcb.ByteSize = bits;
389
390 sr_spew("Configuring %d stop bits.", stopbits);
391 switch (stopbits) {
392 /* Note: There's also ONE5STOPBITS == 1.5 (unneeded so far). */
393 case 1:
394 dcb.StopBits = ONESTOPBIT;
395 break;
396 case 2:
397 dcb.StopBits = TWOSTOPBITS;
398 break;
399 default:
400 sr_err("Unsupported stopbits number: %d.", stopbits);
401 return SR_ERR;
402 }
403
404 switch (parity) {
405 /* Note: There's also SPACEPARITY, MARKPARITY (unneeded so far). */
406 case SERIAL_PARITY_NONE:
407 sr_spew("Configuring no parity.");
408 dcb.Parity = NOPARITY;
409 break;
410 case SERIAL_PARITY_EVEN:
411 sr_spew("Configuring even parity.");
412 dcb.Parity = EVENPARITY;
413 break;
414 case SERIAL_PARITY_ODD:
415 sr_spew("Configuring odd parity.");
416 dcb.Parity = ODDPARITY;
417 break;
418 default:
419 sr_err("Unsupported parity setting: %d.", parity);
420 return SR_ERR;
421 }
422
423 if (rts != -1) {
424 sr_spew("Setting RTS %s.", rts ? "high" : "low");
425 if (rts)
426 dcb.fRtsControl = RTS_CONTROL_ENABLE;
427 else
428 dcb.fRtsControl = RTS_CONTROL_DISABLE;
429 }
430
431 if (dtr != -1) {
432 sr_spew("Setting DTR %s.", dtr ? "high" : "low");
433 if (rts)
434 dcb.fDtrControl = DTR_CONTROL_ENABLE;
435 else
436 dcb.fDtrControl = DTR_CONTROL_DISABLE;
437 }
438
439 if (!SetCommState(hdl, &dcb)) {
440 sr_err("Failed to set comm state on port %s (fd %d): %d.",
441 serial->port, serial->fd, GetLastError());
442 return SR_ERR;
443 }
444#else
445 struct termios term;
446 speed_t baud;
447 int ret, controlbits;
448
449 if (tcgetattr(serial->fd, &term) < 0) {
450 sr_err("tcgetattr() error on port %s (fd %d): %s.",
451 serial->port, serial->fd, strerror(errno));
452 return SR_ERR;
453 }
454
455 switch (baudrate) {
456 case 50:
457 baud = B50;
458 break;
459 case 75:
460 baud = B75;
461 break;
462 case 110:
463 baud = B110;
464 break;
465 case 134:
466 baud = B134;
467 break;
468 case 150:
469 baud = B150;
470 break;
471 case 200:
472 baud = B200;
473 break;
474 case 300:
475 baud = B300;
476 break;
477 case 600:
478 baud = B600;
479 break;
480 case 1200:
481 baud = B1200;
482 break;
483 case 1800:
484 baud = B1800;
485 break;
486 case 2400:
487 baud = B2400;
488 break;
489 case 4800:
490 baud = B4800;
491 break;
492 case 9600:
493 baud = B9600;
494 break;
495 case 19200:
496 baud = B19200;
497 break;
498 case 38400:
499 baud = B38400;
500 break;
501 case 57600:
502 baud = B57600;
503 break;
504 case 115200:
505 baud = B115200;
506 break;
507 case 230400:
508 baud = B230400;
509 break;
510#ifndef __APPLE__
511 case 460800:
512 baud = B460800;
513 break;
514#endif
515 default:
516 sr_err("Unsupported baudrate: %d.", baudrate);
517 return SR_ERR;
518 }
519
520 sr_spew("Configuring output baudrate to %d (%d).", baudrate, baud);
521 if (cfsetospeed(&term, baud) < 0) {
522 sr_err("cfsetospeed() error: %s.", strerror(errno));
523 return SR_ERR;
524 }
525
526 sr_spew("Configuring input baudrate to %d (%d).", baudrate, baud);
527 if (cfsetispeed(&term, baud) < 0) {
528 sr_err("cfsetispeed() error: %s.", strerror(errno));
529 return SR_ERR;
530 }
531
532 sr_spew("Configuring %d data bits.", bits);
533 term.c_cflag &= ~CSIZE;
534 switch (bits) {
535 case 8:
536 term.c_cflag |= CS8;
537 break;
538 case 7:
539 term.c_cflag |= CS7;
540 break;
541 default:
542 sr_err("Unsupported data bits number %d.", bits);
543 return SR_ERR;
544 }
545
546 sr_spew("Configuring %d stop bits.", stopbits);
547 term.c_cflag &= ~CSTOPB;
548 switch (stopbits) {
549 case 1:
550 term.c_cflag &= ~CSTOPB;
551 break;
552 case 2:
553 term.c_cflag |= CSTOPB;
554 break;
555 default:
556 sr_err("Unsupported stopbits number %d.", stopbits);
557 return SR_ERR;
558 }
559
560 term.c_iflag &= ~(IXON | IXOFF);
561 term.c_cflag &= ~CRTSCTS;
562 switch (flowcontrol) {
563 case 0:
564 /* No flow control. */
565 sr_spew("Configuring no flow control.");
566 break;
567 case 1:
568 sr_spew("Configuring RTS/CTS flow control.");
569 term.c_cflag |= CRTSCTS;
570 break;
571 case 2:
572 sr_spew("Configuring XON/XOFF flow control.");
573 term.c_iflag |= IXON | IXOFF;
574 break;
575 default:
576 sr_err("Unsupported flow control setting %d.", flowcontrol);
577 return SR_ERR;
578 }
579
580 term.c_iflag &= ~IGNPAR;
581 term.c_cflag &= ~(PARODD | PARENB);
582 switch (parity) {
583 case SERIAL_PARITY_NONE:
584 sr_spew("Configuring no parity.");
585 term.c_iflag |= IGNPAR;
586 break;
587 case SERIAL_PARITY_EVEN:
588 sr_spew("Configuring even parity.");
589 term.c_cflag |= PARENB;
590 break;
591 case SERIAL_PARITY_ODD:
592 sr_spew("Configuring odd parity.");
593 term.c_cflag |= PARENB | PARODD;
594 break;
595 default:
596 sr_err("Unsupported parity setting %d.", parity);
597 return SR_ERR;
598 }
599
600 /* Do not translate carriage return to newline on input. */
601 term.c_iflag &= ~(ICRNL);
602
603 /* Disable canonical mode, and don't echo input characters. */
604 term.c_lflag &= ~(ICANON | ECHO);
605
606 /* Write the configured settings. */
607 if (tcsetattr(serial->fd, TCSADRAIN, &term) < 0) {
608 sr_err("tcsetattr() error: %s.", strerror(errno));
609 return SR_ERR;
610 }
611
612 if (rts != -1) {
613 sr_spew("Setting RTS %s.", rts ? "high" : "low");
614 controlbits = TIOCM_RTS;
615 if ((ret = ioctl(serial->fd, rts ? TIOCMBIS : TIOCMBIC,
616 &controlbits)) < 0) {
617 sr_err("Error setting RTS: %s.", strerror(errno));
618 return SR_ERR;
619 }
620 }
621
622 if (dtr != -1) {
623 sr_spew("Setting DTR %s.", dtr ? "high" : "low");
624 controlbits = TIOCM_DTR;
625 if ((ret = ioctl(serial->fd, dtr ? TIOCMBIS : TIOCMBIC,
626 &controlbits)) < 0) {
627 sr_err("Error setting DTR: %s.", strerror(errno));
628 return SR_ERR;
629 }
630 }
631
632#endif
633
634 return SR_OK;
635}
636
637/**
638 * Set serial parameters for the specified serial port.
639 *
640 * @param serial Previously initialized serial port structure.
641 * @param paramstr A serial communication parameters string, in the form
642 * of <speed>/<data bits><parity><stopbits>, for example "9600/8n1" or
643 * "600/7o2".
644 *
645 * @return SR_OK upon success, SR_ERR upon failure.
646 */
647#define SERIAL_COMM_SPEC "^(\\d+)/([78])([neo])([12])(.*)$"
648SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
649 const char *paramstr)
650{
651 GRegex *reg;
652 GMatchInfo *match;
653 int speed, databits, parity, stopbits, rts, dtr, i;
654 char *mstr, **opts, **kv;
655
656 speed = databits = parity = stopbits = 0;
657 rts = dtr = -1;
658 sr_spew("Parsing parameters from \"%s\".", paramstr);
659 reg = g_regex_new(SERIAL_COMM_SPEC, 0, 0, NULL);
660 if (g_regex_match(reg, paramstr, 0, &match)) {
661 if ((mstr = g_match_info_fetch(match, 1)))
662 speed = strtoul(mstr, NULL, 10);
663 g_free(mstr);
664 if ((mstr = g_match_info_fetch(match, 2)))
665 databits = strtoul(mstr, NULL, 10);
666 g_free(mstr);
667 if ((mstr = g_match_info_fetch(match, 3))) {
668 switch (mstr[0]) {
669 case 'n':
670 parity = SERIAL_PARITY_NONE;
671 break;
672 case 'e':
673 parity = SERIAL_PARITY_EVEN;
674 break;
675 case 'o':
676 parity = SERIAL_PARITY_ODD;
677 break;
678 }
679 }
680 g_free(mstr);
681 if ((mstr = g_match_info_fetch(match, 4)))
682 stopbits = strtoul(mstr, NULL, 10);
683 g_free(mstr);
684 if ((mstr = g_match_info_fetch(match, 5)) && mstr[0] != '\0') {
685 if (mstr[0] != '/') {
686 sr_dbg("missing separator before extra options");
687 speed = 0;
688 } else {
689 /* A set of "key=value" options separated by / */
690 opts = g_strsplit(mstr + 1, "/", 0);
691 for (i = 0; opts[i]; i++) {
692 kv = g_strsplit(opts[i], "=", 2);
693 if (!strncmp(kv[0], "rts", 3)) {
694 if (kv[1][0] == '1')
695 rts = 1;
696 else if (kv[1][0] == '0')
697 rts = 0;
698 else {
699 sr_dbg("invalid value for rts: %c", kv[1][0]);
700 speed = 0;
701 }
702 } else if (!strncmp(kv[0], "dtr", 3)) {
703 if (kv[1][0] == '1')
704 dtr = 1;
705 else if (kv[1][0] == '0')
706 dtr = 0;
707 else {
708 sr_dbg("invalid value for dtr: %c", kv[1][0]);
709 speed = 0;
710 }
711 }
712 g_strfreev(kv);
713 }
714 g_strfreev(opts);
715 }
716 }
717 g_free(mstr);
718 }
719 g_match_info_unref(match);
720 g_regex_unref(reg);
721
722 if (speed) {
723 return serial_set_params(serial, speed, databits, parity,
724 stopbits, 0, rts, dtr);
725 } else {
726 sr_dbg("Could not infer speed from parameter string.");
727 return SR_ERR_ARG;
728 }
729}
730
731/**
732 * Read a line from the specified serial port.
733 *
734 * @param serial Previously initialized serial port structure.
735 * @param buf Buffer where to store the bytes that are read.
736 * @param buflen Size of the buffer.
737 * @param timeout_ms How long to wait for a line to come in.
738 *
739 * Reading stops when CR of LR is found, which is stripped from the buffer.
740 *
741 * @return SR_OK on success, SR_ERR on failure.
742 */
743SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial, char **buf,
744 int *buflen, gint64 timeout_ms)
745{
746 gint64 start;
747 int maxlen, len;
748
749 if (!serial || serial->fd == -1) {
750 sr_dbg("Invalid serial port.");
751 return SR_ERR;
752 }
753
754 if (serial->fd == -1) {
755 sr_dbg("Cannot use unopened serial port %s (fd %d).",
756 serial->port, serial->fd);
757 return -1;
758 }
759
760 timeout_ms *= 1000;
761 start = g_get_monotonic_time();
762
763 maxlen = *buflen;
764 *buflen = len = 0;
765 while(1) {
766 len = maxlen - *buflen - 1;
767 if (len < 1)
768 break;
769 len = serial_read(serial, *buf + *buflen, 1);
770 if (len > 0) {
771 *buflen += len;
772 *(*buf + *buflen) = '\0';
773 if (*buflen > 0 && (*(*buf + *buflen - 1) == '\r'
774 || *(*buf + *buflen - 1) == '\n')) {
775 /* Strip CR/LF and terminate. */
776 *(*buf + --*buflen) = '\0';
777 break;
778 }
779 }
780 if (g_get_monotonic_time() - start > timeout_ms)
781 /* Timeout */
782 break;
783 g_usleep(2000);
784 }
785 if (*buflen)
786 sr_dbg("Received %d: '%s'.", *buflen, *buf);
787
788 return SR_OK;
789}
790
791/**
792 * Try to find a valid packet in a serial data stream.
793 *
794 * @param serial Previously initialized serial port structure.
795 * @param buf Buffer containing the bytes to write.
796 * @param count Size of the buffer.
797 * @param packet_size Size, in bytes, of a valid packet.
798 * @param is_valid Callback that assesses whether the packet is valid or not.
799 * @param timeout_ms The timeout after which, if no packet is detected, to
800 * abort scanning.
801 * @param baudrate The baudrate of the serial port. This parameter is not
802 * critical, but it helps fine tune the serial port polling
803 * delay.
804 *
805 * @return SR_OK if a valid packet is found within the given timeout,
806 * SR_ERR upon failure.
807 */
808SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
809 uint8_t *buf, size_t *buflen,
810 size_t packet_size, packet_valid_t is_valid,
811 uint64_t timeout_ms, int baudrate)
812{
813 uint64_t start, time, byte_delay_us;
814 size_t ibuf, i, maxlen;
815 int len;
816
817 maxlen = *buflen;
818
819 sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64
820 "ms, baudrate = %d).", serial->fd, timeout_ms, baudrate);
821
822 if (maxlen < (packet_size / 2) ) {
823 sr_err("Buffer size must be at least twice the packet size.");
824 return SR_ERR;
825 }
826
827 /* Assume 8n1 transmission. That is 10 bits for every byte. */
828 byte_delay_us = 10 * (1000000 / baudrate);
829 start = g_get_monotonic_time();
830
831 i = ibuf = len = 0;
832 while (ibuf < maxlen) {
833 len = serial_read(serial, &buf[ibuf], 1);
834 if (len > 0) {
835 ibuf += len;
836 } else if (len == 0) {
837 sr_spew("Error: Only read 0 bytes.");
838 } else {
839 /* Error reading byte, but continuing anyway. */
840 }
841
842 time = g_get_monotonic_time() - start;
843 time /= 1000;
844
845 if ((ibuf - i) >= packet_size) {
846 /* We have at least a packet's worth of data. */
847 if (is_valid(&buf[i])) {
848 sr_spew("Found valid %d-byte packet after "
849 "%" PRIu64 "ms.", (ibuf - i), time);
850 *buflen = ibuf;
851 return SR_OK;
852 } else {
853 sr_spew("Got %d bytes, but not a valid "
854 "packet.", (ibuf - i));
855 }
856 /* Not a valid packet. Continue searching. */
857 i++;
858 }
859 if (time >= timeout_ms) {
860 /* Timeout */
861 sr_dbg("Detection timed out after %dms.", time);
862 break;
863 }
864 g_usleep(byte_delay_us);
865 }
866
867 *buflen = ibuf;
868
869 sr_err("Didn't find a valid packet (read %d bytes).", *buflen);
870
871 return SR_ERR;
872}
Hardware access and backend lib