/*
 * lpc111x-isp/lpc111x.c - LPC111x/LPC11Cxx ISP programmer
 *
 * Written 2012 by Werner Almesberger
 * Copyright 2012 Werner Almesberger
 *
 * 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
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 */


#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <alloca.h>

#include <ubb/ubb.h>
#include <ubb/swuart.h>


#define	TGT_nRESET	UBB_CMD
#define	TGT_nISP	UBB_DAT1
#define	TGT_TX		UBB_DAT3
#define	TGT_RX		UBB_DAT2

#define	HOST_RX		TGT_TX
#define	HOST_TX		TGT_RX

#define	AUTOBAUD_TRIES	10
#define	SYNC		"Synchronized"


/* ----- Debugging and tracing --------------------------------------------- */


static void trace(const char *label, const uint8_t *s, int len)
{
	const uint8_t *end = s+len;

	if (label)
		printf("%s ", label);
	for (end = s+len; s != end; s++) {
		if (*s >= ' ' && *s <= '~')
			printf("%c", *s);
		else if (*s == 10)
			printf(s+1 == end ? "\n" : "\\n");
		else if (*s == 13)
			;
		else
			printf("\\%02o", *s);
	}
	if (len && end[-1] != '\n')
		printf("...\n");
}


static void trace_out(const void *s, int len)
{
	trace(">>>", s, len);
}


static void trace_in(const uint8_t *s, int len)
{
	trace("<<<", s, len);
}


/* ----- Dialog functions -------------------------------------------------- */


static int dialog(const char *cmd, void *buf, int buf_len, int idle)
{
	int cmd_len = strlen(cmd);
	char *tx_buf = alloca(cmd_len+3);
	uint8_t *rx_buf = alloca(cmd_len+2+buf_len);
	int got;

	memcpy(tx_buf, cmd, cmd_len);
	memcpy(tx_buf+cmd_len, "\r\n", 2);

	trace_out(tx_buf, cmd_len+2);
	got = swuart_trx(tx_buf, cmd_len+2, rx_buf, cmd_len+2+buf_len,
	    idle, idle);

	if (got < cmd_len+2) {
		trace_in(rx_buf, got);
		fprintf(stderr, "response too short for echo\n");
		exit(1);
	}
	if (memcmp(rx_buf, cmd, cmd_len) ||
	    rx_buf[cmd_len] != '\r' || rx_buf[cmd_len+1] != '\n') {
		trace_in(rx_buf, got);
		fprintf(stderr, "echo mismatch\n");
		exit(1);
	}

	trace_in(rx_buf, cmd_len+2);

	got -= cmd_len+2;
	memcpy(buf, rx_buf+cmd_len+2, got);

	return got;
}


static int autobaud(void)
{
	uint8_t reply[100];
	int i, got;

	for (i = 0; i != AUTOBAUD_TRIES; i++) {
		CLR(TGT_nRESET);
		usleep(10);	/* DS Table 9 pg 29 says min 50 ns */
		SET(TGT_nRESET);

		usleep(5*1000);	/* UM 26.3.1 pg 408 says max 3 ms */

		got = swuart_trx("?", 1, reply, sizeof(reply), 1000, 100);
		trace_in(reply, got);

		if (got != strlen(SYNC)+2 || memcmp(reply, SYNC "\r\n", got))
			continue;

		got = dialog(SYNC, reply, sizeof(reply), 100);
		trace_in(reply, got);

		if (got == 4 && !memcmp(reply, "OK\r\n", 4))
			return 1;
	}
	return 0;
}


/* ----- ISP session ------------------------------------------------------- */


static void at_exit(void)
{
	ubb_close(0);
}


static void start_isp(void)
{
	uint8_t reply[1000];
	int got;

	if (ubb_open(0) < 0) {
		perror("ubb_open");
		exit(1);
	}
	atexit(at_exit);

	ubb_power(1);

	usleep(100*1000);

	SET(TGT_nRESET);
	OUT(TGT_nRESET);

	CLR(TGT_nISP);
	OUT(TGT_nISP);

	swuart_open(HOST_TX, HOST_RX, 115200);

	if (!autobaud()) {
		fprintf(stderr, "target is not responding\n");
		exit(1);
	}

	got = dialog("12000", reply, sizeof(reply), 100);
	trace_in(reply, got);
	if (got != 4 || memcmp(reply, "OK\r\n", 4)) {
		fprintf(stderr, "cannot set clock rate\n");
		exit(1);
	}
}


/* ----- Command-line processing ------------------------------------------- */


int main(int argc, char **argv)
{
	uint8_t reply[1000];
	int got;

	start_isp();

	got = dialog("J", reply, sizeof(reply), 100);
	trace_in(reply, got);

	return 0;
}