117 lines
3.3 KiB
C
117 lines
3.3 KiB
C
/*
|
|
* (c) 2021 by Tomasz bla Fortuna
|
|
* License: GPLv2
|
|
*
|
|
* This file is shared with the Shine firmware. Keep it in sync (and in the
|
|
* shine's clang formatting).
|
|
*
|
|
* Implementation of a robust serial protocol which can handle single dropped
|
|
* characters during transit without locking.
|
|
*
|
|
* At 115200, transmitting the shortest message takes 0.043ms, at 9600 - 0.52ms.
|
|
*
|
|
*/
|
|
|
|
#include "protocol.h"
|
|
#include "board.h"
|
|
#include "ch.h"
|
|
#include "hal.h"
|
|
|
|
/* UART communication protocol state */
|
|
protocol_t proto;
|
|
|
|
void protoInit(protocol_t *proto, void (*callback)(const message_t *)) {
|
|
proto->previousId = 0;
|
|
proto->callback = callback;
|
|
proto->state = STATE_SYNC_1;
|
|
proto->errors = 0;
|
|
}
|
|
|
|
static uint8_t msgId = 0;
|
|
void protoTx(uint8_t cmd, const unsigned char *buf, int payloadSize, int retries) {
|
|
chDbgCheck(payloadSize <= MAX_PAYLOAD_SIZE);
|
|
|
|
const uint8_t header[5] = {
|
|
0x7A, 0x1D, cmd, ++msgId, payloadSize,
|
|
};
|
|
|
|
/* We don't implement ACKs, yet some messages should not be lost. */
|
|
for (int i = 0; i < retries; i++) {
|
|
sdWrite(&PROTOCOL_SD, header, sizeof(header));
|
|
if (payloadSize) sdWrite(&PROTOCOL_SD, buf, payloadSize);
|
|
}
|
|
}
|
|
|
|
static inline void messageReceived(protocol_t *proto) {
|
|
if (proto->buffer.msgId != proto->previousId) {
|
|
/* It's not a resend / duplicate */
|
|
proto->callback(&proto->buffer);
|
|
proto->previousId = proto->buffer.msgId;
|
|
}
|
|
proto->state = STATE_SYNC_1;
|
|
}
|
|
|
|
void protoConsume(protocol_t *proto, uint8_t byte) {
|
|
switch (proto->state) {
|
|
case STATE_SYNC_1:
|
|
if (byte == 0x7A) {
|
|
proto->state = STATE_SYNC_2;
|
|
} else {
|
|
proto->errors++;
|
|
}
|
|
return;
|
|
|
|
case STATE_SYNC_2:
|
|
if (byte == 0x1D) {
|
|
proto->state = STATE_CMD;
|
|
} else {
|
|
proto->state = STATE_SYNC_1;
|
|
proto->errors++;
|
|
}
|
|
return;
|
|
|
|
case STATE_CMD:
|
|
proto->buffer.command = byte;
|
|
proto->state = STATE_ID;
|
|
return;
|
|
|
|
case STATE_ID:
|
|
proto->buffer.msgId = byte;
|
|
proto->state = STATE_PAYLOAD_SIZE;
|
|
return;
|
|
|
|
case STATE_PAYLOAD_SIZE:
|
|
proto->buffer.payloadSize = byte;
|
|
if (proto->buffer.payloadSize > MAX_PAYLOAD_SIZE) {
|
|
proto->buffer.payloadSize = MAX_PAYLOAD_SIZE;
|
|
proto->errors++;
|
|
}
|
|
proto->payloadPosition = 0;
|
|
if (proto->buffer.payloadSize == 0) {
|
|
/* No payload - whole message received */
|
|
messageReceived(proto);
|
|
} else {
|
|
proto->state = STATE_PAYLOAD;
|
|
}
|
|
return;
|
|
|
|
case STATE_PAYLOAD:
|
|
/* NOTE: This could be read with sdReadTimeout probably, but that breaks
|
|
* abstraction */
|
|
proto->buffer.payload[proto->payloadPosition] = byte;
|
|
proto->payloadPosition++;
|
|
if (proto->payloadPosition == proto->buffer.payloadSize) {
|
|
/* Payload read - message received */
|
|
messageReceived(proto);
|
|
}
|
|
return;
|
|
}
|
|
}
|
|
|
|
void protoSilence(protocol_t *proto) {
|
|
if (proto->state != STATE_SYNC_1) {
|
|
proto->state = STATE_SYNC_1;
|
|
proto->errors++;
|
|
}
|
|
}
|