Move serial_stream_detect() to serial.c.

This commit is contained in:
Uwe Hermann 2012-11-14 18:35:37 +01:00
parent e42b82a66f
commit 766456be1c
3 changed files with 90 additions and 85 deletions

View File

@ -3,6 +3,7 @@
*
* Copyright (C) 2010-2012 Bert Vermeulen <bert@biot.com>
* Copyright (C) 2010-2012 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2012 Alexandru Gagniuc <mr.nuke.me@gmail.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@ -622,3 +623,86 @@ SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial, char **buf,
return SR_OK;
}
/**
* 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 count Size of the buffer.
* @param packet_size Size, in bytes, of a valid packet.
* @param is_valid Callback that assesses whether the packet is valid or not.
* @param timeout_ms The timeout after which, if no packet is detected, to
* abort scanning.
* @param baudrate The baudrate of the serial port. This parameter is not
* critical, but it helps fine tune the serial port polling
* delay.
*
* @return SR_OK if a valid packet is found within the given timeout,
* SR_ERR upon failure.
*/
SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
uint8_t *buf, size_t *buflen,
size_t packet_size, packet_valid_t is_valid,
uint64_t timeout_ms, int baudrate)
{
uint64_t start, time, byte_delay_us;
size_t ibuf, i, maxlen;
int len;
maxlen = *buflen;
sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64
"ms, baudrate = %d).", serial->fd, timeout_ms, baudrate);
if (maxlen < (packet_size / 2) ) {
sr_err("Buffer size must be at least twice the packet size.");
return SR_ERR;
}
timeout_ms *= 1000;
/* Assume 8n1 transmission. That is 10 bits for every byte. */
byte_delay_us = 10 * (1000000 / baudrate);
start = g_get_monotonic_time();
i = ibuf = len = 0;
while (ibuf < maxlen) {
len = serial_read(serial, &buf[ibuf], 1);
if (len > 0) {
ibuf += len;
} else if (len == 0) {
sr_spew("Error: Only read 0 bytes.");
} else {
/* Error reading byte, but continuing anyway. */
}
if ((ibuf - i) >= packet_size) {
/* We have at least a packet's worth of data. */
if (is_valid(&buf[i])) {
time = g_get_monotonic_time() - start;
time /= 1000;
sr_spew("Found valid %d-byte packet after "
"%" PRIu64 "ms.", (ibuf - i), time);
*buflen = ibuf;
return SR_OK;
} else {
sr_spew("Got %d bytes, but not a valid "
"packet.", (ibuf - i));
}
/* Not a valid packet. Continue searching. */
i++;
}
if (g_get_monotonic_time() - start > timeout_ms) {
/* Timeout */
sr_dbg("Detection timed out after %dms.", timeout_ms);
break;
}
g_usleep(byte_delay_us);
}
*buflen = ibuf;
sr_err("Didn't find a valid packet (read %d bytes).", *buflen);
return SR_ERR;
}

View File

@ -91,91 +91,6 @@ static int hw_init(void)
return SR_OK;
}
typedef gboolean (*packet_valid_t)(const uint8_t *buf);
/**
* 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 count Size of the buffer.
* @param packet_size Size, in bytes, of a valid packet.
* @param is_valid Callback that assesses whether the packet is valid or not.
* @param timeout_ms The timeout after which, if no packet is detected, to
* abort scanning.
* @param baudrate The baudrate of the serial port. This parameter is not
* critical, but it helps fine tune the serial port polling
* delay.
*
* @return SR_OK if a valid packet is found within the given timeout,
* SR_ERR upon failure.
*/
static int serial_stream_detect(struct sr_serial_dev_inst *serial,
uint8_t *buf, size_t *buflen,
size_t packet_size, packet_valid_t is_valid,
uint64_t timeout_ms, int baudrate)
{
uint64_t start, time, byte_delay_us;
size_t ibuf, i, maxlen;
int len;
maxlen = *buflen;
sr_dbg("Detecting packets on FD %d (timeout = %" PRIu64
"ms, baudrate = %d).", serial->fd, timeout_ms, baudrate);
if (maxlen < (packet_size / 2) ) {
sr_err("Buffer size must be at least twice the packet size.");
return SR_ERR;
}
timeout_ms *= 1000;
/* Assume 8n1 transmission. That is 10 bits for every byte. */
byte_delay_us = 10 * (1000000 / baudrate);
start = g_get_monotonic_time();
i = ibuf = len = 0;
while (ibuf < maxlen) {
len = serial_read(serial, &buf[ibuf], 1);
if (len > 0) {
ibuf += len;
} else if (len == 0) {
sr_spew("Error: Only read 0 bytes.");
} else {
/* Error reading byte, but continuing anyway. */
}
if ((ibuf - i) >= packet_size) {
/* We have at least a packet's worth of data. */
if (is_valid(&buf[i])) {
time = g_get_monotonic_time() - start;
time /= 1000;
sr_spew("Found valid %d-byte packet after "
"%" PRIu64 "ms.", (ibuf - i), time);
*buflen = ibuf;
return SR_OK;
} else {
sr_spew("Got %d bytes, but not a valid "
"packet.", (ibuf - i));
}
/* Not a valid packet. Continue searching. */
i++;
}
if (g_get_monotonic_time() - start > timeout_ms) {
/* Timeout */
sr_dbg("Detection timed out after %dms.", timeout_ms);
break;
}
g_usleep(byte_delay_us);
}
*buflen = ibuf;
sr_err("Didn't find a valid packet (read %d bytes).", *buflen);
return SR_ERR;
}
static GSList *lcd14_scan(const char *conn, const char *serialcomm)
{
struct sr_dev_inst *sdi;

View File

@ -125,6 +125,8 @@ SR_PRIV int sr_session_send(const struct sr_dev_inst *sdi,
/*--- hardware/common/serial.c ----------------------------------------------*/
typedef gboolean (*packet_valid_t)(const uint8_t *buf);
SR_PRIV int serial_open(struct sr_serial_dev_inst *serial, int flags);
SR_PRIV int serial_close(struct sr_serial_dev_inst *serial);
SR_PRIV int serial_flush(struct sr_serial_dev_inst *serial);
@ -138,6 +140,10 @@ SR_PRIV int serial_set_paramstr(struct sr_serial_dev_inst *serial,
const char *paramstr);
SR_PRIV int serial_readline(struct sr_serial_dev_inst *serial, char **buf,
int *buflen, gint64 timeout_ms);
SR_PRIV int serial_stream_detect(struct sr_serial_dev_inst *serial,
uint8_t *buf, size_t *buflen,
size_t packet_size, packet_valid_t is_valid,
uint64_t timeout_ms, int baudrate);
/*--- hardware/common/ezusb.c -----------------------------------------------*/