libsigrok  0.5.2
sigrok hardware access and backend library
serial.c
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1 /*
2  * This file is part of the libsigrok 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  * Copyright (C) 2014 Uffe Jakobsen <uffe@uffe.org>
8  * Copyright (C) 2017-2019 Gerhard Sittig <gerhard.sittig@gmx.net>
9  *
10  * This program is free software: you can redistribute it and/or modify
11  * it under the terms of the GNU General Public License as published by
12  * the Free Software Foundation, either version 3 of the License, or
13  * (at your option) any later version.
14  *
15  * This program is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18  * GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program. If not, see <http://www.gnu.org/licenses/>.
22  */
23 
24 #include <config.h>
25 #include <string.h>
26 #include <stdlib.h>
27 #include <glib.h>
28 #include <glib/gstdio.h>
29 #ifdef HAVE_LIBSERIALPORT
30 #include <libserialport.h>
31 #endif
32 #include <libsigrok/libsigrok.h>
33 #include "libsigrok-internal.h"
34 #ifdef _WIN32
35 #include <windows.h> /* for HANDLE */
36 #endif
37 
38 /** @cond PRIVATE */
39 #define LOG_PREFIX "serial"
40 /** @endcond */
41 
42 /**
43  * @file
44  *
45  * Serial port handling.
46  */
47 
48 /**
49  * @defgroup grp_serial Serial port handling
50  *
51  * Serial port handling functions.
52  *
53  * @{
54  */
55 
56 #ifdef HAVE_SERIAL_COMM
57 
58 /* See if an (assumed opened) serial port is of any supported type. */
59 static int dev_is_supported(struct sr_serial_dev_inst *serial)
60 {
61  if (!serial || !serial->lib_funcs)
62  return 0;
63 
64  return 1;
65 }
66 
67 /**
68  * Open the specified serial port.
69  *
70  * @param serial Previously initialized serial port structure.
71  * @param[in] flags Flags to use when opening the serial port. Possible flags
72  * include SERIAL_RDWR, SERIAL_RDONLY.
73  *
74  * If the serial structure contains a serialcomm string, it will be
75  * passed to serial_set_paramstr() after the port is opened.
76  *
77  * @retval SR_OK Success.
78  * @retval SR_ERR Failure.
79  *
80  * @private
81  */
82 SR_PRIV int serial_open(struct sr_serial_dev_inst *serial, int flags)
83 {
84  int ret;
85 
86  if (!serial) {
87  sr_dbg("Invalid serial port.");
88  return SR_ERR;
89  }
90 
91  sr_spew("Opening serial port '%s' (flags %d).", serial->port, flags);
92 
93  /*
94  * Determine which serial transport library to use. Derive the
95  * variant from the serial port's name. Default to libserialport
96  * for backwards compatibility.
97  */
98  if (ser_name_is_hid(serial))
99  serial->lib_funcs = ser_lib_funcs_hid;
100  else if (ser_name_is_bt(serial))
101  serial->lib_funcs = ser_lib_funcs_bt;
102  else
103  serial->lib_funcs = ser_lib_funcs_libsp;
104  if (!serial->lib_funcs)
105  return SR_ERR_NA;
106 
107  /*
108  * Note that use of the 'rcv_buffer' is optional, and the buffer's
109  * size heavily depends on the specific transport. That's why the
110  * buffer's content gets accessed and the buffer is released here in
111  * common code, but the buffer gets allocated in libraries' open()
112  * routines.
113  */
114 
115  /*
116  * Run the transport's open routine. Setup the bitrate and the
117  * UART frame format.
118  */
119  if (!serial->lib_funcs->open)
120  return SR_ERR_NA;
121  ret = serial->lib_funcs->open(serial, flags);
122  if (ret != SR_OK)
123  return ret;
124 
125  if (serial->serialcomm)
126  return serial_set_paramstr(serial, serial->serialcomm);
127  else
128  return SR_OK;
129 }
130 
131 /**
132  * Close the specified serial port.
133  *
134  * @param serial Previously initialized serial port structure.
135  *
136  * @retval SR_OK Success.
137  * @retval SR_ERR Failure.
138  *
139  * @private
140  */
141 SR_PRIV int serial_close(struct sr_serial_dev_inst *serial)
142 {
143  int rc;
144 
145  if (!serial) {
146  sr_dbg("Invalid serial port.");
147  return SR_ERR;
148  }
149 
150  sr_spew("Closing serial port %s.", serial->port);
151 
152  if (!serial->lib_funcs || !serial->lib_funcs->close)
153  return SR_ERR_NA;
154 
155  rc = serial->lib_funcs->close(serial);
156  if (rc == SR_OK && serial->rcv_buffer) {
157  g_string_free(serial->rcv_buffer, TRUE);
158  serial->rcv_buffer = NULL;
159  }
160 
161  return rc;
162 }
163 
164 /**
165  * Flush serial port buffers. Empty buffers, discard pending RX and TX data.
166  *
167  * @param serial Previously initialized serial port structure.
168  *
169  * @retval SR_OK Success.
170  * @retval SR_ERR Failure.
171  *
172  * @private
173  */
174 SR_PRIV int serial_flush(struct sr_serial_dev_inst *serial)
175 {
176  if (!serial) {
177  sr_dbg("Invalid serial port.");
178  return SR_ERR;
179  }
180 
181  sr_spew("Flushing serial port %s.", serial->port);
182 
183  sr_ser_discard_queued_data(serial);
184 
185  if (!serial->lib_funcs || !serial->lib_funcs->flush)
186  return SR_ERR_NA;
187 
188  return serial->lib_funcs->flush(serial);
189 }
190 
191 /**
192  * Drain serial port buffers. Wait for pending TX data to be sent.
193  *
194  * @param serial Previously initialized serial port structure.
195  *
196  * @retval SR_OK Success.
197  * @retval SR_ERR Failure.
198  *
199  * @private
200  */
201 SR_PRIV int serial_drain(struct sr_serial_dev_inst *serial)
202 {
203  if (!serial) {
204  sr_dbg("Invalid serial port.");
205  return SR_ERR;
206  }
207 
208  sr_spew("Draining serial port %s.", serial->port);
209 
210  if (!serial->lib_funcs || !serial->lib_funcs->drain)
211  return SR_ERR_NA;
212 
213  return serial->lib_funcs->drain(serial);
214 }
215 
216 /*
217  * Provide an internal RX data buffer for the serial port. This is not
218  * supposed to be used directly by applications. Instead optional and
219  * alternative transports for serial communication can use this buffer
220  * if their progress is driven from background activity, and is not
221  * (directly) driven by external API calls.
222  *
223  * BEWARE! This implementation assumes that data which gets communicated
224  * via UART can get stored in a GString (which is a char array). Since
225  * the API hides this detail, we can address this issue later when needed.
226  * Callers use the API which communicates bytes.
227  *
228  * Applications optionally can register a "per RX chunk" callback, when
229  * they depend on the frame boundaries of the respective physical layer.
230  * Most callers just want the stream of RX data, and can use the buffer.
231  *
232  * The availability of RX chunks to callbacks, as well as the capability
233  * to pass on exact frames as chunks or potential re-assembly of chunks
234  * to a single data block, depend on each transport's implementation.
235  */
236 
237 /**
238  * Register application callback for RX data chunks.
239  *
240  * @param[in] serial Previously initialized serial port instance.
241  * @param[in] cb Routine to call as RX data becomes available.
242  * @param[in] cb_data User data to pass to the callback in addition to RX data.
243  *
244  * @retval SR_ERR_ARG Invalid parameters.
245  * @retval SR_OK Successful registration.
246  *
247  * Callbacks get unregistered by specifying #NULL for the 'cb' parameter.
248  */
249 SR_PRIV int serial_set_read_chunk_cb(struct sr_serial_dev_inst *serial,
250  serial_rx_chunk_callback cb, void *cb_data)
251 {
252  if (!serial)
253  return SR_ERR_ARG;
254 
255  serial->rx_chunk_cb_func = cb;
256  serial->rx_chunk_cb_data = cb_data;
257 
258  return SR_OK;
259 }
260 
261 /**
262  * Discard previously queued RX data. Internal to the serial subsystem,
263  * coordination between common and transport specific support code.
264  *
265  * @param[in] serial Previously opened serial port instance.
266  *
267  * @internal
268  */
269 SR_PRIV void sr_ser_discard_queued_data(struct sr_serial_dev_inst *serial)
270 {
271  if (!serial || !serial->rcv_buffer)
272  return;
273 
274  g_string_truncate(serial->rcv_buffer, 0);
275 }
276 
277 /**
278  * Get amount of queued RX data. Internal to the serial subsystem,
279  * coordination between common and transport specific support code.
280  *
281  * @param[in] serial Previously opened serial port instance.
282  *
283  * @internal
284  */
285 SR_PRIV size_t sr_ser_has_queued_data(struct sr_serial_dev_inst *serial)
286 {
287  if (!serial || !serial->rcv_buffer)
288  return 0;
289 
290  return serial->rcv_buffer->len;
291 }
292 
293 /**
294  * Queue received data. Internal to the serial subsystem, coordination
295  * between common and transport specific support code.
296  *
297  * @param[in] serial Previously opened serial port instance.
298  * @param[in] data Pointer to data bytes to queue.
299  * @param[in] len Number of data bytes to queue.
300  *
301  * @internal
302  */
303 SR_PRIV void sr_ser_queue_rx_data(struct sr_serial_dev_inst *serial,
304  const uint8_t *data, size_t len)
305 {
306  if (!serial || !data || !len)
307  return;
308 
309  if (serial->rx_chunk_cb_func)
310  serial->rx_chunk_cb_func(serial, serial->rx_chunk_cb_data, data, len);
311  else if (serial->rcv_buffer)
312  g_string_append_len(serial->rcv_buffer, (const gchar *)data, len);
313 }
314 
315 /**
316  * Retrieve previously queued RX data. Internal to the serial subsystem,
317  * coordination between common and transport specific support code.
318  *
319  * @param[in] serial Previously opened serial port instance.
320  * @param[out] data Pointer to store retrieved data bytes into.
321  * @param[in] len Number of data bytes to retrieve.
322  *
323  * @internal
324  */
325 SR_PRIV size_t sr_ser_unqueue_rx_data(struct sr_serial_dev_inst *serial,
326  uint8_t *data, size_t len)
327 {
328  size_t qlen;
329  GString *buf;
330 
331  if (!serial || !data || !len)
332  return 0;
333 
334  qlen = sr_ser_has_queued_data(serial);
335  if (!qlen)
336  return 0;
337 
338  buf = serial->rcv_buffer;
339  if (len > buf->len)
340  len = buf->len;
341  if (len) {
342  memcpy(data, buf->str, len);
343  g_string_erase(buf, 0, len);
344  }
345 
346  return len;
347 }
348 
349 /**
350  * Check for available receive data.
351  *
352  * @param[in] serial Previously opened serial port instance.
353  *
354  * @returns The number of (known) available RX data bytes.
355  *
356  * Returns 0 if no receive data is available, or if the amount of
357  * available receive data cannot get determined.
358  */
359 SR_PRIV size_t serial_has_receive_data(struct sr_serial_dev_inst *serial)
360 {
361  size_t lib_count, buf_count;
362 
363  if (!serial)
364  return 0;
365 
366  lib_count = 0;
367  if (serial->lib_funcs && serial->lib_funcs->get_rx_avail)
368  lib_count = serial->lib_funcs->get_rx_avail(serial);
369 
370  buf_count = sr_ser_has_queued_data(serial);
371 
372  return lib_count + buf_count;
373 }
374 
375 static int _serial_write(struct sr_serial_dev_inst *serial,
376  const void *buf, size_t count,
377  int nonblocking, unsigned int timeout_ms)
378 {
379  ssize_t ret;
380 
381  if (!serial) {
382  sr_dbg("Invalid serial port.");
383  return SR_ERR;
384  }
385 
386  if (!serial->lib_funcs || !serial->lib_funcs->write)
387  return SR_ERR_NA;
388  ret = serial->lib_funcs->write(serial, buf, count,
389  nonblocking, timeout_ms);
390  sr_spew("Wrote %zd/%zu bytes.", ret, count);
391 
392  return ret;
393 }
394 
395 /**
396  * Write a number of bytes to the specified serial port, blocking until finished.
397  *
398  * @param serial Previously initialized serial port structure.
399  * @param[in] buf Buffer containing the bytes to write.
400  * @param[in] count Number of bytes to write.
401  * @param[in] timeout_ms Timeout in ms, or 0 for no timeout.
402  *
403  * @retval SR_ERR_ARG Invalid argument.
404  * @retval SR_ERR Other error.
405  * @retval other The number of bytes written. If this is less than the number
406  * specified in the call, the timeout was reached.
407  *
408  * @private
409  */
410 SR_PRIV int serial_write_blocking(struct sr_serial_dev_inst *serial,
411  const void *buf, size_t count, unsigned int timeout_ms)
412 {
413  return _serial_write(serial, buf, count, 0, timeout_ms);
414 }
415 
416 /**
417  * Write a number of bytes to the specified serial port, return immediately.
418  *
419  * @param serial Previously initialized serial port structure.
420  * @param[in] buf Buffer containing the bytes to write.
421  * @param[in] count Number of bytes to write.
422  *
423  * @retval SR_ERR_ARG Invalid argument.
424  * @retval SR_ERR Other error.
425  * @retval other The number of bytes written.
426  *
427  * @private
428  */
429 SR_PRIV int serial_write_nonblocking(struct sr_serial_dev_inst *serial,
430  const void *buf, size_t count)
431 {
432  return _serial_write(serial, buf, count, 1, 0);
433 }
434 
435 static int _serial_read(struct sr_serial_dev_inst *serial,
436  void *buf, size_t count, int nonblocking, unsigned int timeout_ms)
437 {
438  ssize_t ret;
439 
440  if (!serial) {
441  sr_dbg("Invalid serial port.");
442  return SR_ERR;
443  }
444 
445  if (!serial->lib_funcs || !serial->lib_funcs->read)
446  return SR_ERR_NA;
447  ret = serial->lib_funcs->read(serial, buf, count,
448  nonblocking, timeout_ms);
449  if (ret > 0)
450  sr_spew("Read %zd/%zu bytes.", ret, count);
451 
452  return ret;
453 }
454 
455 /**
456  * Read a number of bytes from the specified serial port, block until finished.
457  *
458  * @param serial Previously initialized serial port structure.
459  * @param buf Buffer where to store the bytes that are read.
460  * @param[in] count The number of bytes to read.
461  * @param[in] timeout_ms Timeout in ms, or 0 for no timeout.
462  *
463  * @retval SR_ERR_ARG Invalid argument.
464  * @retval SR_ERR Other error.
465  * @retval other The number of bytes read. If this is less than the number
466  * requested, the timeout was reached.
467  *
468  * @private
469  */
470 SR_PRIV int serial_read_blocking(struct sr_serial_dev_inst *serial,
471  void *buf, size_t count, unsigned int timeout_ms)
472 {
473  return _serial_read(serial, buf, count, 0, timeout_ms);
474 }
475 
476 /**
477  * Try to read up to @a count bytes from the specified serial port, return
478  * immediately with what's available.
479  *
480  * @param serial Previously initialized serial port structure.
481  * @param buf Buffer where to store the bytes that are read.
482  * @param[in] count The number of bytes to read.
483  *
484  * @retval SR_ERR_ARG Invalid argument.
485  * @retval SR_ERR Other error.
486  * @retval other The number of bytes read.
487  *
488  * @private
489  */
490 SR_PRIV int serial_read_nonblocking(struct sr_serial_dev_inst *serial,
491  void *buf, size_t count)
492 {
493  return _serial_read(serial, buf, count, 1, 0);
494 }
495 
496 /**
497  * Set serial parameters for the specified serial port.
498  *
499  * @param serial Previously initialized serial port structure.
500  * @param[in] baudrate The baudrate to set.
501  * @param[in] bits The number of data bits to use (5, 6, 7 or 8).
502  * @param[in] parity The parity setting to use (0 = none, 1 = even, 2 = odd).
503  * @param[in] stopbits The number of stop bits to use (1 or 2).
504  * @param[in] flowcontrol The flow control settings to use (0 = none,
505  * 1 = RTS/CTS, 2 = XON/XOFF).
506  * @param[in] rts Status of RTS line (0 or 1; required by some interfaces).
507  * @param[in] dtr Status of DTR line (0 or 1; required by some interfaces).
508  *
509  * @retval SR_OK Success.
510  * @retval SR_ERR Failure.
511  *
512  * @private
513  */
514 SR_PRIV int serial_set_params(struct sr_serial_dev_inst *serial,
515  int baudrate, int bits, int parity, int stopbits,
516  int flowcontrol, int rts, int dtr)
517 {
518  int ret;
519 
520  if (!serial) {
521  sr_dbg("Invalid serial port.");
522  return SR_ERR;
523  }
524 
525  sr_spew("Setting serial parameters on port %s.", serial->port);
526 
527  if (!serial->lib_funcs || !serial->lib_funcs->set_params)
528  return SR_ERR_NA;
529  ret = serial->lib_funcs->set_params(serial,
530  baudrate, bits, parity, stopbits,
531  flowcontrol, rts, dtr);
532  if (ret == SR_OK) {
533  serial->comm_params.bit_rate = baudrate;
534  serial->comm_params.data_bits = bits;
535  serial->comm_params.parity_bits = parity ? 1 : 0;
536  serial->comm_params.stop_bits = stopbits;
537  sr_dbg("DBG: %s() rate %d, %d%s%d", __func__,
538  baudrate, bits,
539  (parity == 0) ? "n" : "x",
540  stopbits);
541  }
542 
543  return ret;
544 }
545 
546 /**
547  * Set serial parameters for the specified serial port from parameter string.
548  *
549  * @param serial Previously initialized serial port structure.
550  * @param[in] paramstr A serial communication parameters string of the form
551  * "<baudrate>/<bits><parity><stopbits>{/<option>}".\n
552  * Examples: "9600/8n1", "600/7o2/dtr=1/rts=0" or "460800/8n1/flow=2".\n
553  * <baudrate>=integer Baud rate.\n
554  * <bits>=5|6|7|8 Number of data bits.\n
555  * <parity>=n|e|o None, even, odd.\n
556  * <stopbits>=1|2 One or two stop bits.\n
557  * Options:\n
558  * dtr=0|1 Set DTR off resp. on.\n
559  * flow=0|1|2 Flow control. 0 for none, 1 for RTS/CTS, 2 for XON/XOFF.\n
560  * rts=0|1 Set RTS off resp. on.\n
561  * Please note that values and combinations of these parameters must be
562  * supported by the concrete serial interface hardware and the drivers for it.
563  *
564  * @retval SR_OK Success.
565  * @retval SR_ERR Failure.
566  *
567  * @private
568  */
569 SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
570  const char *paramstr)
571 {
572 /** @cond PRIVATE */
573 #define SERIAL_COMM_SPEC "^(\\d+)/([5678])([neo])([12])(.*)$"
574 /** @endcond */
575 
576  GRegex *reg;
577  GMatchInfo *match;
578  int speed, databits, parity, stopbits, flow, rts, dtr, i;
579  char *mstr, **opts, **kv;
580 
581  speed = databits = parity = stopbits = flow = 0;
582  rts = dtr = -1;
583  sr_spew("Parsing parameters from \"%s\".", paramstr);
584  reg = g_regex_new(SERIAL_COMM_SPEC, 0, 0, NULL);
585  if (g_regex_match(reg, paramstr, 0, &match)) {
586  if ((mstr = g_match_info_fetch(match, 1)))
587  speed = strtoul(mstr, NULL, 10);
588  g_free(mstr);
589  if ((mstr = g_match_info_fetch(match, 2)))
590  databits = strtoul(mstr, NULL, 10);
591  g_free(mstr);
592  if ((mstr = g_match_info_fetch(match, 3))) {
593  switch (mstr[0]) {
594  case 'n':
595  parity = SP_PARITY_NONE;
596  break;
597  case 'e':
598  parity = SP_PARITY_EVEN;
599  break;
600  case 'o':
601  parity = SP_PARITY_ODD;
602  break;
603  }
604  }
605  g_free(mstr);
606  if ((mstr = g_match_info_fetch(match, 4)))
607  stopbits = strtoul(mstr, NULL, 10);
608  g_free(mstr);
609  if ((mstr = g_match_info_fetch(match, 5)) && mstr[0] != '\0') {
610  if (mstr[0] != '/') {
611  sr_dbg("missing separator before extra options");
612  speed = 0;
613  } else {
614  /* A set of "key=value" options separated by / */
615  opts = g_strsplit(mstr + 1, "/", 0);
616  for (i = 0; opts[i]; i++) {
617  kv = g_strsplit(opts[i], "=", 2);
618  if (!strncmp(kv[0], "rts", 3)) {
619  if (kv[1][0] == '1')
620  rts = 1;
621  else if (kv[1][0] == '0')
622  rts = 0;
623  else {
624  sr_dbg("invalid value for rts: %c", kv[1][0]);
625  speed = 0;
626  }
627  } else if (!strncmp(kv[0], "dtr", 3)) {
628  if (kv[1][0] == '1')
629  dtr = 1;
630  else if (kv[1][0] == '0')
631  dtr = 0;
632  else {
633  sr_dbg("invalid value for dtr: %c", kv[1][0]);
634  speed = 0;
635  }
636  } else if (!strncmp(kv[0], "flow", 4)) {
637  if (kv[1][0] == '0')
638  flow = 0;
639  else if (kv[1][0] == '1')
640  flow = 1;
641  else if (kv[1][0] == '2')
642  flow = 2;
643  else {
644  sr_dbg("invalid value for flow: %c", kv[1][0]);
645  speed = 0;
646  }
647  }
648  g_strfreev(kv);
649  }
650  g_strfreev(opts);
651  }
652  }
653  g_free(mstr);
654  }
655  g_match_info_unref(match);
656  g_regex_unref(reg);
657 
658  if (speed) {
659  return serial_set_params(serial, speed, databits, parity,
660  stopbits, flow, rts, dtr);
661  } else {
662  sr_dbg("Could not infer speed from parameter string.");
663  return SR_ERR_ARG;
664  }
665 }
666 
667 /**
668  * Read a line from the specified serial port.
669  *
670  * @param[in] serial Previously initialized serial port structure.
671  * @param[out] buf Buffer where to store the bytes that are read.
672  * @param[in] buflen Size of the buffer.
673  * @param[in] timeout_ms How long to wait for a line to come in.
674  *
675  * Reading stops when CR or LF is found, which is stripped from the buffer.
676  *
677  * @retval SR_OK Success.
678  * @retval SR_ERR Failure.
679  *
680  * @private
681  */
682 SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial,
683  char **buf, int *buflen, gint64 timeout_ms)
684 {
685  gint64 start, remaining;
686  int maxlen, len;
687 
688  if (!serial) {
689  sr_dbg("Invalid serial port.");
690  return SR_ERR;
691  }
692 
693  if (!dev_is_supported(serial)) {
694  sr_dbg("Cannot use unopened serial port %s.", serial->port);
695  return -1;
696  }
697 
698  start = g_get_monotonic_time();
699  remaining = timeout_ms;
700 
701  maxlen = *buflen;
702  *buflen = len = 0;
703  while (1) {
704  len = maxlen - *buflen - 1;
705  if (len < 1)
706  break;
707  len = serial_read_blocking(serial, *buf + *buflen, 1, remaining);
708  if (len > 0) {
709  *buflen += len;
710  *(*buf + *buflen) = '\0';
711  if (*buflen > 0 && (*(*buf + *buflen - 1) == '\r'
712  || *(*buf + *buflen - 1) == '\n')) {
713  /* Strip CR/LF and terminate. */
714  *(*buf + --*buflen) = '\0';
715  break;
716  }
717  }
718  /* Reduce timeout by time elapsed. */
719  remaining = timeout_ms - ((g_get_monotonic_time() - start) / 1000);
720  if (remaining <= 0)
721  /* Timeout */
722  break;
723  if (len < 1)
724  g_usleep(2000);
725  }
726  if (*buflen)
727  sr_dbg("Received %d: '%s'.", *buflen, *buf);
728 
729  return SR_OK;
730 }
731 
732 /**
733  * Try to find a valid packet in a serial data stream.
734  *
735  * @param serial Previously initialized serial port structure.
736  * @param buf Buffer containing the bytes to write.
737  * @param buflen Size of the buffer.
738  * @param[in] packet_size Size, in bytes, of a valid packet.
739  * @param is_valid Callback that assesses whether the packet is valid or not.
740  * @param[in] timeout_ms The timeout after which, if no packet is detected, to
741  * abort scanning.
742  *
743  * @retval SR_OK Valid packet was found within the given timeout.
744  * @retval SR_ERR Failure.
745  *
746  * @private
747  */
748 SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
749  uint8_t *buf, size_t *buflen,
750  size_t packet_size,
751  packet_valid_callback is_valid,
752  uint64_t timeout_ms)
753 {
754  uint64_t start, time, byte_delay_us;
755  size_t ibuf, i, maxlen;
756  ssize_t len;
757 
758  maxlen = *buflen;
759 
760  sr_dbg("Detecting packets on %s (timeout = %" PRIu64 "ms).",
761  serial->port, timeout_ms);
762 
763  if (maxlen < (packet_size * 2) ) {
764  sr_err("Buffer size must be at least twice the packet size.");
765  return SR_ERR;
766  }
767 
768  /* Assume 8n1 transmission. That is 10 bits for every byte. */
769  byte_delay_us = serial_timeout(serial, 1) * 1000;
770  start = g_get_monotonic_time();
771 
772  i = ibuf = len = 0;
773  while (ibuf < maxlen) {
774  len = serial_read_nonblocking(serial, &buf[ibuf], 1);
775  if (len > 0) {
776  ibuf += len;
777  } else if (len == 0) {
778  /* No logging, already done in serial_read(). */
779  } else {
780  /* Error reading byte, but continuing anyway. */
781  }
782 
783  time = g_get_monotonic_time() - start;
784  time /= 1000;
785 
786  if ((ibuf - i) >= packet_size) {
787  GString *text;
788  /* We have at least a packet's worth of data. */
789  text = sr_hexdump_new(&buf[i], packet_size);
790  sr_spew("Trying packet: %s", text->str);
791  sr_hexdump_free(text);
792  if (is_valid(&buf[i])) {
793  sr_spew("Found valid %zu-byte packet after "
794  "%" PRIu64 "ms.", (ibuf - i), time);
795  *buflen = ibuf;
796  return SR_OK;
797  } else {
798  sr_spew("Got %zu bytes, but not a valid "
799  "packet.", (ibuf - i));
800  }
801  /* Not a valid packet. Continue searching. */
802  i++;
803  }
804  if (time >= timeout_ms) {
805  /* Timeout */
806  sr_dbg("Detection timed out after %" PRIu64 "ms.", time);
807  break;
808  }
809  if (len < 1)
810  g_usleep(byte_delay_us);
811  }
812 
813  *buflen = ibuf;
814 
815  sr_err("Didn't find a valid packet (read %zu bytes).", *buflen);
816 
817  return SR_ERR;
818 }
819 
820 /**
821  * Extract the serial device and options from the options linked list.
822  *
823  * @param options List of options passed from the command line.
824  * @param serial_device Pointer where to store the extracted serial device.
825  * @param serial_options Pointer where to store the optional extracted serial
826  * options.
827  *
828  * @return SR_OK if a serial_device is found, SR_ERR if no device is found. The
829  * returned string should not be freed by the caller.
830  *
831  * @private
832  */
833 SR_PRIV int sr_serial_extract_options(GSList *options,
834  const char **serial_device, const char **serial_options)
835 {
836  GSList *l;
837  struct sr_config *src;
838 
839  *serial_device = NULL;
840 
841  for (l = options; l; l = l->next) {
842  src = l->data;
843  switch (src->key) {
844  case SR_CONF_CONN:
845  *serial_device = g_variant_get_string(src->data, NULL);
846  sr_dbg("Parsed serial device: %s.", *serial_device);
847  break;
848  case SR_CONF_SERIALCOMM:
849  *serial_options = g_variant_get_string(src->data, NULL);
850  sr_dbg("Parsed serial options: %s.", *serial_options);
851  break;
852  }
853  }
854 
855  if (!*serial_device) {
856  sr_dbg("No serial device specified.");
857  return SR_ERR;
858  }
859 
860  return SR_OK;
861 }
862 
863 /** @private */
864 SR_PRIV int serial_source_add(struct sr_session *session,
865  struct sr_serial_dev_inst *serial, int events, int timeout,
866  sr_receive_data_callback cb, void *cb_data)
867 {
868  if ((events & (G_IO_IN | G_IO_ERR)) && (events & G_IO_OUT)) {
869  sr_err("Cannot poll input/error and output simultaneously.");
870  return SR_ERR_ARG;
871  }
872 
873  if (!dev_is_supported(serial)) {
874  sr_err("Invalid serial port.");
875  return SR_ERR_ARG;
876  }
877 
878  if (!serial->lib_funcs || !serial->lib_funcs->setup_source_add)
879  return SR_ERR_NA;
880 
881  return serial->lib_funcs->setup_source_add(session, serial,
882  events, timeout, cb, cb_data);
883 }
884 
885 /** @private */
886 SR_PRIV int serial_source_remove(struct sr_session *session,
887  struct sr_serial_dev_inst *serial)
888 {
889  if (!dev_is_supported(serial)) {
890  sr_err("Invalid serial port.");
891  return SR_ERR_ARG;
892  }
893 
894  if (!serial->lib_funcs || !serial->lib_funcs->setup_source_remove)
895  return SR_ERR_NA;
896 
897  return serial->lib_funcs->setup_source_remove(session, serial);
898 }
899 
900 /**
901  * Create/allocate a new sr_serial_port structure.
902  *
903  * @param name The OS dependent name of the serial port. Must not be NULL.
904  * @param description An end user friendly description for the serial port.
905  * Can be NULL (in that case the empty string is used
906  * as description).
907  *
908  * @return The newly allocated sr_serial_port struct.
909  */
910 static struct sr_serial_port *sr_serial_new(const char *name,
911  const char *description)
912 {
913  struct sr_serial_port *serial;
914 
915  if (!name)
916  return NULL;
917 
918  serial = g_malloc0(sizeof(*serial));
919  serial->name = g_strdup(name);
920  serial->description = g_strdup(description ? description : "");
921 
922  return serial;
923 }
924 
925 /**
926  * Free a previously allocated sr_serial_port structure.
927  *
928  * @param serial The sr_serial_port struct to free. Must not be NULL.
929  */
930 SR_API void sr_serial_free(struct sr_serial_port *serial)
931 {
932  if (!serial)
933  return;
934  g_free(serial->name);
935  g_free(serial->description);
936  g_free(serial);
937 }
938 
939 static GSList *append_port_list(GSList *devs, const char *name, const char *desc)
940 {
941  return g_slist_append(devs, sr_serial_new(name, desc));
942 }
943 
944 /**
945  * List available serial devices.
946  *
947  * @return A GSList of strings containing the path of the serial devices or
948  * NULL if no serial device is found. The returned list must be freed
949  * by the caller.
950  */
951 SR_API GSList *sr_serial_list(const struct sr_dev_driver *driver)
952 {
953  GSList *tty_devs;
954  GSList *(*list_func)(GSList *list, sr_ser_list_append_t append);
955 
956  /* Currently unused, but will be used by some drivers later on. */
957  (void)driver;
958 
959  tty_devs = NULL;
961  list_func = ser_lib_funcs_libsp->list;
962  tty_devs = list_func(tty_devs, append_port_list);
963  }
964  if (ser_lib_funcs_hid && ser_lib_funcs_hid->list) {
965  list_func = ser_lib_funcs_hid->list;
966  tty_devs = list_func(tty_devs, append_port_list);
967  }
968  if (ser_lib_funcs_bt && ser_lib_funcs_bt->list) {
969  list_func = ser_lib_funcs_bt->list;
970  tty_devs = list_func(tty_devs, append_port_list);
971  }
972 
973  return tty_devs;
974 }
975 
976 static GSList *append_port_find(GSList *devs, const char *name)
977 {
978  if (!name || !*name)
979  return devs;
980 
981  return g_slist_append(devs, g_strdup(name));
982 }
983 
984 /**
985  * Find USB serial devices via the USB vendor ID and product ID.
986  *
987  * @param[in] vendor_id Vendor ID of the USB device.
988  * @param[in] product_id Product ID of the USB device.
989  *
990  * @return A GSList of strings containing the path of the serial device or
991  * NULL if no serial device is found. The returned list must be freed
992  * by the caller.
993  *
994  * @private
995  */
996 SR_PRIV GSList *sr_serial_find_usb(uint16_t vendor_id, uint16_t product_id)
997 {
998  GSList *tty_devs;
999  GSList *(*find_func)(GSList *list, sr_ser_find_append_t append,
1000  uint16_t vid, uint16_t pid);
1001 
1002  tty_devs = NULL;
1003  if (ser_lib_funcs_libsp && ser_lib_funcs_libsp->find_usb) {
1004  find_func = ser_lib_funcs_libsp->find_usb;
1005  tty_devs = find_func(tty_devs, append_port_find,
1006  vendor_id, product_id);
1007  }
1008  if (ser_lib_funcs_hid && ser_lib_funcs_hid->find_usb) {
1009  find_func = ser_lib_funcs_hid->find_usb;
1010  tty_devs = find_func(tty_devs, append_port_find,
1011  vendor_id, product_id);
1012  }
1013 
1014  return tty_devs;
1015 }
1016 
1017 /** @private */
1018 SR_PRIV int serial_timeout(struct sr_serial_dev_inst *port, int num_bytes)
1019 {
1020  int bits, baud, ret, timeout_ms;
1021 
1022  /* Get the bitrate and frame length. */
1023  bits = baud = 0;
1024  if (port->lib_funcs && port->lib_funcs->get_frame_format) {
1025  ret = port->lib_funcs->get_frame_format(port, &baud, &bits);
1026  if (ret != SR_OK)
1027  bits = baud = 0;
1028  } else {
1029  baud = port->comm_params.bit_rate;
1030  bits = 1 + port->comm_params.data_bits +
1031  port->comm_params.parity_bits +
1032  port->comm_params.stop_bits;
1033  }
1034 
1035  /* Derive the timeout. Default to 1s. */
1036  timeout_ms = 1000;
1037  if (bits && baud) {
1038  /* Throw in 10ms for misc OS overhead. */
1039  timeout_ms = 10;
1040  timeout_ms += ((1000.0 / baud) * bits) * num_bytes;
1041  }
1042 
1043  return timeout_ms;
1044 }
1045 
1046 #else
1047 
1048 /* TODO Put fallback.c content here? */
1049 
1050 #endif
1051 
1052 /** @} */
Generic/unspecified error.
Definition: libsigrok.h:68
No error.
Definition: libsigrok.h:67
The public libsigrok header file to be used by frontends.
char * name
The OS dependent name of the serial port.
Definition: libsigrok.h:1208
SR_PRIV GString * sr_hexdump_new(const uint8_t *data, const size_t len)
Convert a sequence of bytes to its textual representation ("hex dump").
Definition: strutil.c:603
int(* sr_receive_data_callback)(int fd, int revents, void *cb_data)
Type definition for callback function for data reception.
Definition: libsigrok.h:134
GSList * sr_serial_list(const struct sr_dev_driver *driver)
Serial port descriptor.
Definition: libsigrok.h:1206
SR_PRIV void sr_hexdump_free(GString *s)
Free a hex dump text that was created by sr_hexdump_new().
Definition: strutil.c:623
Used for setting or getting value of a config item.
Definition: libsigrok.h:623
Specification on how to connect to a device.
Definition: libsigrok.h:723
GVariant * data
Key-specific data.
Definition: libsigrok.h:627
Not applicable.
Definition: libsigrok.h:73
void sr_serial_free(struct sr_serial_port *serial)
#define SR_PRIV
Definition: libsigrok.h:128
char * description
An end user friendly description for the serial port.
Definition: libsigrok.h:1210
Serial communication specification, in the form:
Definition: libsigrok.h:744
Device driver data.
Definition: libsigrok.h:1138
Function argument error.
Definition: libsigrok.h:70
uint32_t key
Config key like SR_CONF_CONN, etc.
Definition: libsigrok.h:625
SR_PRIV struct ser_lib_functions * ser_lib_funcs_libsp
Definition: serial_libsp.c:512
Opaque structure representing a libsigrok session.
Definition: libsigrok.h:456
#define SR_API
Definition: libsigrok.h:121