]> sigrok.org Git - libsigrok.git/blobdiff - src/serial.c
scpi-pps: Support for the EEZ PSU series
[libsigrok.git] / src / serial.c
index 7f08b7b3804ee037a566960705e35bbc8a0c45bb..97bd3159b094f673e0db8070d87eadb960e1cab8 100644 (file)
@@ -122,10 +122,24 @@ SR_PRIV int serial_open(struct sr_serial_dev_inst *serial, int flags)
        if (ret != SR_OK)
                return ret;
 
-       if (serial->serialcomm)
-               return serial_set_paramstr(serial, serial->serialcomm);
-       else
-               return SR_OK;
+       if (serial->serialcomm) {
+               ret = serial_set_paramstr(serial, serial->serialcomm);
+               if (ret != SR_OK)
+                       return ret;
+       }
+
+       /*
+        * Flush potentially dangling RX data. Availability of the
+        * flush primitive depends on the transport/cable, absense
+        * is non-fatal.
+        */
+       ret = serial_flush(serial);
+       if (ret == SR_ERR_NA)
+               ret = SR_OK;
+       if (ret != SR_OK)
+               return ret;
+
+       return SR_OK;
 }
 
 /**
@@ -244,7 +258,7 @@ SR_PRIV int serial_drain(struct sr_serial_dev_inst *serial)
  * @retval SR_ERR_ARG Invalid parameters.
  * @retval SR_OK Successful registration.
  *
- * Callbacks get unregistered by specifying #NULL for the 'cb' parameter.
+ * Callbacks get unregistered by specifying NULL for the 'cb' parameter.
  *
  * @private
  */
@@ -547,6 +561,37 @@ SR_PRIV int serial_set_params(struct sr_serial_dev_inst *serial,
        return ret;
 }
 
+/**
+ * Manipulate handshake state for the specified serial port.
+ *
+ * @param serial Previously initialized serial port structure.
+ * @param[in] rts Status of RTS line (0 or 1; or -1 to ignore).
+ * @param[in] dtr Status of DTR line (0 or 1; or -1 to ignore).
+ *
+ * @retval SR_OK Success.
+ * @retval SR_ERR Failure.
+ *
+ * @private
+ */
+SR_PRIV int serial_set_handshake(struct sr_serial_dev_inst *serial,
+       int rts, int dtr)
+{
+       int ret;
+
+       if (!serial) {
+               sr_dbg("Invalid serial port.");
+               return SR_ERR;
+       }
+
+       sr_spew("Modifying serial parameters on port %s.", serial->port);
+
+       if (!serial->lib_funcs || !serial->lib_funcs->set_handshake)
+               return SR_ERR_NA;
+       ret = serial->lib_funcs->set_handshake(serial, rts, dtr);
+
+       return ret;
+}
+
 /**
  * Set serial parameters for the specified serial port from parameter string.
  *
@@ -574,7 +619,7 @@ SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
        const char *paramstr)
 {
 /** @cond PRIVATE */
-#define SERIAL_COMM_SPEC "^(\\d+)/([5678])([neo])([12])(.*)$"
+#define SERIAL_COMM_SPEC "^(\\d+)(/([5678])([neo])([12]))?(.*)$"
 /** @endcond */
 
        GRegex *reg;
@@ -582,7 +627,10 @@ SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
        int speed, databits, parity, stopbits, flow, rts, dtr, i;
        char *mstr, **opts, **kv;
 
-       speed = databits = parity = stopbits = flow = 0;
+       speed = flow = 0;
+       databits = 8;
+       parity = SP_PARITY_NONE;
+       stopbits = 1;
        rts = dtr = -1;
        sr_spew("Parsing parameters from \"%s\".", paramstr);
        reg = g_regex_new(SERIAL_COMM_SPEC, 0, 0, NULL);
@@ -590,10 +638,10 @@ SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
                if ((mstr = g_match_info_fetch(match, 1)))
                        speed = strtoul(mstr, NULL, 10);
                g_free(mstr);
-               if ((mstr = g_match_info_fetch(match, 2)))
+               if ((mstr = g_match_info_fetch(match, 3)) && mstr[0])
                        databits = strtoul(mstr, NULL, 10);
                g_free(mstr);
-               if ((mstr = g_match_info_fetch(match, 3))) {
+               if ((mstr = g_match_info_fetch(match, 4)) && mstr[0]) {
                        switch (mstr[0]) {
                        case 'n':
                                parity = SP_PARITY_NONE;
@@ -607,10 +655,10 @@ SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
                        }
                }
                g_free(mstr);
-               if ((mstr = g_match_info_fetch(match, 4)))
+               if ((mstr = g_match_info_fetch(match, 5)) && mstr[0])
                        stopbits = strtoul(mstr, NULL, 10);
                g_free(mstr);
-               if ((mstr = g_match_info_fetch(match, 5)) && mstr[0] != '\0') {
+               if ((mstr = g_match_info_fetch(match, 6)) && mstr[0] != '\0') {
                        if (mstr[0] != '/') {
                                sr_dbg("missing separator before extra options");
                                speed = 0;
@@ -658,14 +706,17 @@ SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
        }
        g_match_info_unref(match);
        g_regex_unref(reg);
+       sr_spew("Got params: rate %d, frame %d/%d/%d, flow %d, rts %d, dtr %d.",
+               speed, databits, parity, stopbits, flow, rts, dtr);
 
-       if (speed) {
-               return serial_set_params(serial, speed, databits, parity,
-                                        stopbits, flow, rts, dtr);
-       } else {
+       if (!speed) {
                sr_dbg("Could not infer speed from parameter string.");
                return SR_ERR_ARG;
        }
+
+       return serial_set_params(serial, speed,
+                       databits, parity, stopbits,
+                       flow, rts, dtr);
 }
 
 /**
@@ -736,14 +787,24 @@ SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial,
 /**
  * Try to find a valid packet in a serial data stream.
  *
- * @param serial Previously initialized serial port structure.
- * @param buf Buffer containing the bytes to write.
- * @param buflen Size of the buffer.
+ * @param[in] serial Previously initialized serial port structure.
+ * @param[in] buf Buffer containing the bytes to write.
+ * @param[in] buflen Size of the buffer.
  * @param[in] packet_size Size, in bytes, of a valid packet.
- * @param is_valid Callback that assesses whether the packet is valid or not.
+ * @param[in] is_valid Callback that assesses whether the packet is valid or not.
+ * @param[in] is_valid_len Callback which checks a variable length packet.
+ * @param[out] return_size Detected packet size in case of successful match.
  * @param[in] timeout_ms The timeout after which, if no packet is detected, to
  *                       abort scanning.
  *
+ * Data is received from the serial port and into the caller provided
+ * buffer, until the buffer is exhausted, or the timeout has expired,
+ * or a valid packet was found. Receive data is passed to the caller
+ * provided validity check routine, assuming either fixed size packets
+ * (#is_valid parameter, exact match to the #packet_size length) or
+ * packets of variable length (#is_valid_len parameter, minimum length
+ * #packet_size required for first invocation).
+ *
  * @retval SR_OK Valid packet was found within the given timeout.
  * @retval SR_ERR Failure.
  *
@@ -751,72 +812,115 @@ SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial,
  */
 SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
        uint8_t *buf, size_t *buflen,
-       size_t packet_size,
-       packet_valid_callback is_valid,
+       size_t packet_size, packet_valid_callback is_valid,
+       packet_valid_len_callback is_valid_len, size_t *return_size,
        uint64_t timeout_ms)
 {
-       uint64_t start, time, byte_delay_us;
-       size_t ibuf, i, maxlen;
-       ssize_t len;
-
-       maxlen = *buflen;
+       uint64_t start_us, elapsed_ms, byte_delay_us;
+       size_t fill_idx, check_idx, max_fill_idx;
+       ssize_t recv_len;
+       const uint8_t *check_ptr;
+       size_t check_len, pkt_len;
+       gboolean do_dump;
+       int ret;
 
        sr_dbg("Detecting packets on %s (timeout = %" PRIu64 "ms).",
                serial->port, timeout_ms);
 
-       if (maxlen < (packet_size * 2) ) {
-               sr_err("Buffer size must be at least twice the packet size.");
-               return SR_ERR;
+       max_fill_idx = *buflen;
+       if (max_fill_idx < 2 * packet_size) {
+               /*
+                * The heuristics in this check is only useful for fixed
+                * packet length scenarios, but for variable length setups
+                * we don't know the packets' sizes up front.
+                */
+               sr_err("Small stream detect RX buffer, want 2x packet size.");
+               return SR_ERR_ARG;
        }
 
-       /* Assume 8n1 transmission. That is 10 bits for every byte. */
        byte_delay_us = serial_timeout(serial, 1) * 1000;
-       start = g_get_monotonic_time();
+       start_us = g_get_monotonic_time();
+
+       check_idx = fill_idx = 0;
+       while (fill_idx < max_fill_idx) {
+               /*
+                * Read bytes individually. Lets callers continue to
+                * successfully process next RX data after first match.
+                * Run full loop bodies for empty or failed reception
+                * in an iteration, to have timeouts checked.
+                */
+               recv_len = serial_read_nonblocking(serial, &buf[fill_idx], 1);
+               if (recv_len > 0)
+                       fill_idx += recv_len;
+
+               /* Dump receive data when (a minimum) size is reached. */
+               check_ptr = &buf[check_idx];
+               check_len = fill_idx - check_idx;
+               do_dump = check_len >= packet_size;
+               do_dump &= sr_log_loglevel_get() >= SR_LOG_SPEW;
+               if (do_dump) {
+                       GString *text;
 
-       i = ibuf = len = 0;
-       while (ibuf < maxlen) {
-               len = serial_read_nonblocking(serial, &buf[ibuf], 1);
-               if (len > 0) {
-                       ibuf += len;
-               } else if (len == 0) {
-                       /* No logging, already done in serial_read(). */
-               } else {
-                       /* Error reading byte, but continuing anyway. */
+                       text = sr_hexdump_new(check_ptr, check_len);
+                       sr_spew("Trying packet: len %zu, bytes %s",
+                               check_len, text->str);
+                       sr_hexdump_free(text);
                }
 
-               time = g_get_monotonic_time() - start;
-               time /= 1000;
-
-               if ((ibuf - i) >= packet_size) {
-                       GString *text;
-                       /* We have at least a packet's worth of data. */
-                       text = sr_hexdump_new(&buf[i], packet_size);
-                       sr_spew("Trying packet: %s", text->str);
-                       sr_hexdump_free(text);
-                       if (is_valid(&buf[i])) {
-                               sr_spew("Found valid %zu-byte packet after "
-                                       "%" PRIu64 "ms.", (ibuf - i), time);
-                               *buflen = ibuf;
+               /* A packet's (minimum) length was received, check its data. */
+               elapsed_ms = g_get_monotonic_time() - start_us;
+               elapsed_ms /= 1000;
+               if (is_valid_len && check_len >= packet_size) {
+                       pkt_len = packet_size;
+                       ret = is_valid_len(NULL, check_ptr, check_len, &pkt_len);
+                       if (ret == SR_PACKET_VALID) {
+                               /* Exact match. Terminate with success. */
+                               sr_spew("Valid packet after %" PRIu64 "ms.",
+                                       elapsed_ms);
+                               sr_spew("RX count %zu, packet len %zu.",
+                                       fill_idx, pkt_len);
+                               *buflen = fill_idx;
+                               if (return_size)
+                                       *return_size = pkt_len;
                                return SR_OK;
+                       }
+                       if (ret == SR_PACKET_NEED_RX) {
+                               /* Incomplete, keep accumulating RX data. */
+                               sr_spew("Checker needs more RX data.");
                        } else {
-                               sr_spew("Got %zu bytes, but not a valid "
-                                       "packet.", (ibuf - i));
+                               /* Not a valid packet. Continue searching. */
+                               sr_spew("Invalid packet, advancing read pos.");
+                               check_idx++;
+                       }
+               }
+               if (is_valid && check_len >= packet_size) {
+                       if (is_valid(check_ptr)) {
+                               /* Exact match. Terminate with success. */
+                               sr_spew("Valid packet after %" PRIu64 "ms.",
+                                       elapsed_ms);
+                               sr_spew("RX count %zu, packet len %zu.",
+                                       fill_idx, packet_size);
+                               *buflen = fill_idx;
+                               if (return_size)
+                                       *return_size = packet_size;
+                               return SR_OK;
                        }
                        /* Not a valid packet. Continue searching. */
-                       i++;
+                       sr_spew("Invalid packet, advancing read pointer.");
+                       check_idx++;
                }
-               if (time >= timeout_ms) {
-                       /* Timeout */
-                       sr_dbg("Detection timed out after %" PRIu64 "ms.", time);
+
+               /* Check for packet search timeout. */
+               if (elapsed_ms >= timeout_ms) {
+                       sr_dbg("Detection timed out after %" PRIu64 "ms.",
+                               elapsed_ms);
                        break;
                }
-               if (len < 1)
+               if (recv_len < 1)
                        g_usleep(byte_delay_us);
        }
-
-       *buflen = ibuf;
-
-       sr_err("Didn't find a valid packet (read %zu bytes).", *buflen);
+       sr_info("Didn't find a valid packet (read %zu bytes).", fill_idx);
+       *buflen = fill_idx;
 
        return SR_ERR;
 }
@@ -824,13 +928,20 @@ SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
 /**
  * Extract the serial device and options from the options linked list.
  *
- * @param options List of options passed from the command line.
- * @param serial_device Pointer where to store the extracted serial device.
- * @param serial_options Pointer where to store the optional extracted serial
+ * The caller's passed in references get updated when the list of options
+ * contains one of the desired parameters. This lets callers pre-assign
+ * default values which take effect in the absence of user specifications.
+ * Either reference is optional, passing #NULL is acceptable.
+ *
+ * Callers must not free returned strings. These shall be considered
+ * read-only handles to data that is managed elsewhere.
+ *
+ * @param[in] options List of options passed from the command line.
+ * @param[out] serial_device Pointer where to store the extracted serial device.
+ * @param[out] serial_options Pointer where to store the optional extracted serial
  * options.
  *
- * @return SR_OK if a serial_device is found, SR_ERR if no device is found. The
- * returned string should not be freed by the caller.
+ * @return SR_OK if a serial_device is found, SR_ERR if no device is found.
  *
  * @private
  */
@@ -840,23 +951,25 @@ SR_PRIV int sr_serial_extract_options(GSList *options,
        GSList *l;
        struct sr_config *src;
 
-       *serial_device = NULL;
-
        for (l = options; l; l = l->next) {
                src = l->data;
                switch (src->key) {
                case SR_CONF_CONN:
+                       if (!serial_device)
+                               break;
                        *serial_device = g_variant_get_string(src->data, NULL);
                        sr_dbg("Parsed serial device: %s.", *serial_device);
                        break;
                case SR_CONF_SERIALCOMM:
+                       if (!serial_options)
+                               break;
                        *serial_options = g_variant_get_string(src->data, NULL);
                        sr_dbg("Parsed serial options: %s.", *serial_options);
                        break;
                }
        }
 
-       if (!*serial_device) {
+       if (serial_device && !*serial_device) {
                sr_dbg("No serial device specified.");
                return SR_ERR;
        }