2 * This file is part of the libsigrok project.
4 * Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 3 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
23 static void handle_packet(const uint8_t *buf, struct sr_dev_inst *sdi)
26 struct dev_context *devc;
27 struct sr_datafeed_packet packet;
28 struct sr_datafeed_analog_old analog;
32 analog.num_samples = 1;
35 if (brymen_parse(buf, &floatval, &analog, NULL) != SR_OK)
37 analog.data = &floatval;
39 analog.channels = sdi->channels;
41 if (analog.mq != -1) {
42 /* Got a measurement. */
43 packet.type = SR_DF_ANALOG_OLD;
44 packet.payload = &analog;
45 sr_session_send(sdi, &packet);
46 sr_sw_limits_update_samples_read(&devc->sw_limits, 1);
50 static void handle_new_data(struct sr_dev_inst *sdi)
52 struct dev_context *devc;
53 int len, status, offset = 0;
54 struct sr_serial_dev_inst *serial;
59 /* Try to get as much data as the buffer can hold. */
60 len = DMM_BUFSIZE - devc->buflen;
61 len = serial_read_nonblocking(serial, devc->buf + devc->buflen, len);
63 sr_err("Serial port read error: %d.", len);
67 status = PACKET_INVALID_HEADER;
69 /* Now look for packets in that data. */
70 while (status != PACKET_NEED_MORE_DATA) {
71 /* We don't have a header, look for one. */
72 if (devc->next_packet_len == 0) {
73 len = devc->buflen - offset;
74 status = brymen_packet_length(devc->buf + offset, &len);
75 if (status == PACKET_HEADER_OK) {
76 /* We know how large the packet will be. */
77 devc->next_packet_len = len;
78 } else if (status == PACKET_NEED_MORE_DATA) {
79 /* We didn't yet receive the full header. */
80 devc->next_packet_len = 0;
83 /* Invalid header. Move on. */
84 devc->next_packet_len = 0;
90 /* We know how the packet size, but did we receive all of it? */
91 if (devc->buflen - offset < devc->next_packet_len)
94 /* We should have a full packet here, so we can check it. */
95 if (brymen_packet_is_valid(devc->buf + offset)) {
96 handle_packet(devc->buf + offset, sdi);
97 offset += devc->next_packet_len;
102 /* We are done with this packet. Look for a new one. */
103 devc->next_packet_len = 0;
106 /* If we have any data left, move it to the beginning of our buffer. */
107 memmove(devc->buf, devc->buf + offset, devc->buflen - offset);
108 devc->buflen -= offset;
111 SR_PRIV int brymen_dmm_receive_data(int fd, int revents, void *cb_data)
113 struct sr_dev_inst *sdi;
114 struct dev_context *devc;
115 struct sr_serial_dev_inst *serial;
120 if (!(sdi = cb_data))
123 if (!(devc = sdi->priv))
128 if (revents == G_IO_IN) {
129 /* Serial data arrived. */
130 handle_new_data(sdi);
132 /* Timeout, send another packet request. */
133 if ((ret = brymen_packet_request(serial)) < 0) {
134 sr_err("Failed to request packet: %d.", ret);
139 if (sr_sw_limits_check(&devc->sw_limits))
140 sdi->driver->dev_acquisition_stop(sdi);
146 * Try to find a valid packet in a serial data stream.
148 * @param serial Previously initialized serial port structure.
149 * @param buf Buffer containing the bytes to write.
150 * @param buflen Size of the buffer.
151 * @param get_packet_size Callback that assesses the size of incoming packets.
152 * @param is_valid Callback that assesses whether the packet is valid or not.
153 * @param timeout_ms The timeout after which, if no packet is detected, to
155 * @param baudrate The baudrate of the serial port. This parameter is not
156 * critical, but it helps fine tune the serial port polling
159 * @return SR_OK if a valid packet is found within the given timeout,
160 * SR_ERR upon failure.
162 SR_PRIV int brymen_stream_detect(struct sr_serial_dev_inst *serial,
163 uint8_t *buf, size_t *buflen,
164 packet_length_t get_packet_size,
165 packet_valid_callback is_valid,
166 uint64_t timeout_ms, int baudrate)
168 int64_t start, time, byte_delay_us;
169 size_t ibuf, i, maxlen;
170 ssize_t len, stream_len;
176 sr_dbg("Detecting packets on %s (timeout = %" PRIu64
177 "ms, baudrate = %d).", serial->port, timeout_ms, baudrate);
179 /* Assume 8n1 transmission. That is 10 bits for every byte. */
180 byte_delay_us = 10 * ((1000 * 1000) / baudrate);
181 start = g_get_monotonic_time();
183 packet_len = i = ibuf = len = 0;
184 while (ibuf < maxlen) {
185 len = serial_read_nonblocking(serial, &buf[ibuf], maxlen - ibuf);
188 sr_spew("Read %zd bytes.", len);
191 time = g_get_monotonic_time() - start;
194 stream_len = ibuf - i;
195 if (stream_len > 0 && packet_len == 0) {
196 /* How large of a packet are we expecting? */
197 packet_len = stream_len;
198 status = get_packet_size(&buf[i], &packet_len);
200 case PACKET_HEADER_OK:
201 /* We know how much data we need to wait for. */
203 case PACKET_NEED_MORE_DATA:
204 /* We did not receive the full header. */
207 case PACKET_INVALID_HEADER:
210 * We had enough data, but here was an error in
211 * parsing the header. Restart parsing from the
220 if ((stream_len >= packet_len) && (packet_len != 0)) {
221 /* We have at least a packet's worth of data. */
222 if (is_valid(&buf[i])) {
223 sr_spew("Found valid %d-byte packet after "
224 "%" PRIu64 "ms.", packet_len, time);
228 sr_spew("Got %d bytes, but not a valid "
229 "packet.", packet_len);
233 /* Not a valid packet. Continue searching. */
238 if (time >= (int64_t)timeout_ms) {
240 sr_dbg("Detection timed out after %" PRIi64 "ms.", time);
243 g_usleep(byte_delay_us);
247 sr_err("Didn't find a valid packet (read %zu bytes).", ibuf);