261 lines
6.9 KiB
C
261 lines
6.9 KiB
C
/*
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* This file is part of the libsigrok project.
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*
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* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include "protocol.h"
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static void handle_packet(const uint8_t *buf, struct sr_dev_inst *sdi)
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{
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float floatval;
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struct dev_context *devc;
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struct sr_datafeed_packet packet;
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struct sr_datafeed_analog analog;
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devc = sdi->priv;
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analog.num_samples = 1;
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analog.mq = -1;
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if (brymen_parse(buf, &floatval, &analog, NULL) != SR_OK)
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return;
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analog.data = &floatval;
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analog.channels = sdi->channels;
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if (analog.mq != -1) {
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/* Got a measurement. */
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packet.type = SR_DF_ANALOG;
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packet.payload = &analog;
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sr_session_send(devc->cb_data, &packet);
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devc->num_samples++;
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}
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}
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static void handle_new_data(struct sr_dev_inst *sdi)
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{
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struct dev_context *devc;
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int len, status, offset = 0;
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struct sr_serial_dev_inst *serial;
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devc = sdi->priv;
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serial = sdi->conn;
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/* Try to get as much data as the buffer can hold. */
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len = DMM_BUFSIZE - devc->buflen;
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len = serial_read(serial, devc->buf + devc->buflen, len);
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if (len < 1) {
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sr_err("Serial port read error: %d.", len);
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return;
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}
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devc->buflen += len;
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status = PACKET_INVALID_HEADER;
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/* Now look for packets in that data. */
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while (status != PACKET_NEED_MORE_DATA) {
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/* We don't have a header, look for one. */
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if (devc->next_packet_len == 0) {
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len = devc->buflen - offset;
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status = brymen_packet_length(devc->buf + offset, &len);
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if (status == PACKET_HEADER_OK) {
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/* We know how large the packet will be. */
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devc->next_packet_len = len;
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} else if (status == PACKET_NEED_MORE_DATA) {
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/* We didn't yet receive the full header. */
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devc->next_packet_len = 0;
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break;
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} else {
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/* Invalid header. Move on. */
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devc->next_packet_len = 0;
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offset++;
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continue;
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}
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}
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/* We know how the packet size, but did we receive all of it? */
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if (devc->buflen - offset < devc->next_packet_len)
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break;
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/* We should have a full packet here, so we can check it. */
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if (brymen_packet_is_valid(devc->buf + offset)) {
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handle_packet(devc->buf + offset, sdi);
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offset += devc->next_packet_len;
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} else {
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offset++;
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}
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/* We are done with this packet. Look for a new one. */
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devc->next_packet_len = 0;
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}
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/* If we have any data left, move it to the beginning of our buffer. */
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memmove(devc->buf, devc->buf + offset, devc->buflen - offset);
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devc->buflen -= offset;
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}
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SR_PRIV int brymen_dmm_receive_data(int fd, int revents, void *cb_data)
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{
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struct sr_dev_inst *sdi;
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struct dev_context *devc;
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struct sr_serial_dev_inst *serial;
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int ret;
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int64_t time;
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(void)fd;
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if (!(sdi = cb_data))
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return TRUE;
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if (!(devc = sdi->priv))
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return TRUE;
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serial = sdi->conn;
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if (revents == G_IO_IN) {
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/* Serial data arrived. */
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handle_new_data(sdi);
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} else {
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/* Timeout, send another packet request. */
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if ((ret = brymen_packet_request(serial)) < 0) {
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sr_err("Failed to request packet: %d.", ret);
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return FALSE;
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}
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}
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if (devc->limit_samples && devc->num_samples >= devc->limit_samples) {
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sr_info("Requested number of samples reached, stopping.");
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sdi->driver->dev_acquisition_stop(sdi, cb_data);
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return TRUE;
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}
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if (devc->limit_msec) {
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time = (g_get_monotonic_time() - devc->starttime) / 1000;
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if (time > (int64_t)devc->limit_msec) {
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sr_info("Requested time limit reached, stopping.");
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sdi->driver->dev_acquisition_stop(sdi, cb_data);
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return TRUE;
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}
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}
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return TRUE;
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}
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/**
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* Try to find a valid packet in a serial data stream.
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*
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* @param serial Previously initialized serial port structure.
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* @param buf Buffer containing the bytes to write.
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* @param buflen Size of the buffer.
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* @param get_packet_size Callback that assesses the size of incoming packets.
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* @param is_valid Callback that assesses whether the packet is valid or not.
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* @param timeout_ms The timeout after which, if no packet is detected, to
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* abort scanning.
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* @param baudrate The baudrate of the serial port. This parameter is not
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* critical, but it helps fine tune the serial port polling
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* delay.
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*
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* @return SR_OK if a valid packet is found within the given timeout,
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* SR_ERR upon failure.
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*/
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SR_PRIV int brymen_stream_detect(struct sr_serial_dev_inst *serial,
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uint8_t *buf, size_t *buflen,
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packet_length_t get_packet_size,
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packet_valid_t is_valid,
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uint64_t timeout_ms, int baudrate)
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{
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int64_t start, time, byte_delay_us;
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size_t ibuf, i, maxlen;
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int status, len, packet_len, stream_len;
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maxlen = *buflen;
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sr_dbg("Detecting packets on %s (timeout = %" PRIu64
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"ms, baudrate = %d).", serial->port, timeout_ms, baudrate);
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/* Assume 8n1 transmission. That is 10 bits for every byte. */
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byte_delay_us = 10 * (1000000 / baudrate);
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start = g_get_monotonic_time();
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packet_len = i = ibuf = len = 0;
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while (ibuf < maxlen) {
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len = serial_read(serial, &buf[ibuf], maxlen - ibuf);
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if (len > 0) {
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ibuf += len;
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sr_spew("Read %d bytes.", len);
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}
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time = g_get_monotonic_time() - start;
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time /= 1000;
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stream_len = ibuf - i;
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if (stream_len > 0 && packet_len == 0) {
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/* How large of a packet are we expecting? */
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packet_len = stream_len;
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status = get_packet_size(&buf[i], &packet_len);
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switch(status) {
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case PACKET_HEADER_OK:
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/* We know how much data we need to wait for. */
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break;
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case PACKET_NEED_MORE_DATA:
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/* We did not receive the full header. */
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packet_len = 0;
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break;
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case PACKET_INVALID_HEADER:
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default:
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/*
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* We had enough data, but here was an error in
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* parsing the header. Restart parsing from the
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* next byte.
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*/
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packet_len = 0;
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i++;
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break;
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}
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}
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if ((stream_len >= packet_len) && (packet_len != 0)) {
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/* We have at least a packet's worth of data. */
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if (is_valid(&buf[i])) {
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sr_spew("Found valid %d-byte packet after "
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"%" PRIu64 "ms.", packet_len, time);
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*buflen = ibuf;
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return SR_OK;
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} else {
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sr_spew("Got %d bytes, but not a valid "
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"packet.", packet_len);
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}
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/* Not a valid packet. Continue searching. */
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i++;
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packet_len = 0;
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}
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if (time >= (int64_t)timeout_ms) {
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/* Timeout */
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sr_dbg("Detection timed out after %dms.", time);
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break;
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}
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g_usleep(byte_delay_us);
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}
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*buflen = ibuf;
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sr_err("Didn't find a valid packet (read %d bytes).", ibuf);
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return SR_ERR;
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}
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