/*
 * dbgrst.c - Reset a Neo through the debug board
 *
 * Copyright (C) 2008 by OpenMoko, Inc.
 * Written by Werner Almesberger <werner@openmoko.org>
 * All Rights Reserved
 *
 * 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 <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#include <ftdi.h>


#define nTRST_ENABLE	0x1	/* ACBUS0/GPIOH0 */
#define nTRST		0x2	/* ACBUS1/GPIOH1 */
#define nSRST_ENABLE	0x4	/* ACBUS2/GPIOH2 */
#define nSRST		0x8	/* ACBUS3/GPIOH3 */


static const struct id {
	uint16_t vendor;
	uint16_t product;
} ids[] = {
	{ 0x0403, 0x6010 },	/* FTDI default IDs */
	{ 0x1457, 0x5118 },	/* Neo1973 debug board (FIC) */
	{ 0x1d50, 0x5118 },	/* Neo1973 debug board (OpenMoko) */
	{ 0 }
};


static struct ftdi_context ftdi;


static void open_ftdi(void)
{
	const struct id *id;

	if (ftdi_init(&ftdi) < 0) {
		fprintf(stderr, "ftdi_init failed\n");
		exit(1);
	}
	for (id = ids; id->vendor; id++)
		if (ftdi_usb_open(&ftdi, id->vendor, id->product) >= 0)
			break;
	if (!id->vendor) {
		fprintf(stderr, "no debug board found\n");
		exit(1);
	}

#if 0	/* not needed */
	fprintf(stderr, "%04x:%04x\n", id->vendor, id->product);
	ftdi_set_interface(&ftdi, INTERFACE_A);
	ftdi_usb_reset(&ftdi);

	ftdi_set_latency_timer(&ftdi, 2);
#endif

	if (ftdi_set_bitmode(&ftdi, 0x0b, BITMODE_MPSSE) < 0) {
		fprintf(stderr, "ftdi_set_bitmode: %s\n",
		    ftdi_get_error_string(&ftdi));
		exit(1);
	}
}


static void set_high(uint8_t data, uint8_t direction)
{
	uint8_t buf[3] = {
		SET_BITS_HIGH,
		data,
		direction,
	};
	int i;

	/*
	 * For some reason, the FTDI sometimes doesn't accept the setting.
	 * So we repeat a number of times to make it clear that compliance
	 * is not optional.
	 */
	for (i = 0; i != 10; i++)
		if (ftdi_write_data(&ftdi, buf, 3) < 0) {
			fprintf(stderr, "ftdi_write_data: %s\n",
			    ftdi_get_error_string(&ftdi));
			exit(1);
		}
}


static void pulse_reset(void)
{
	/*
	 * We also have to make sure we don't assert nTRST.
	 */
	set_high(nTRST | nTRST_ENABLE, 0x0f);
	set_high(nTRST | nTRST_ENABLE | nSRST | nSRST_ENABLE, 0x0f);
}


static void usage(const char *name)
{
	fprintf(stderr, "usage; %s\n", name);
	exit(1);
}


int main(int argc, char **argv)
{
	if (argc != 1)
		usage(*argv);
	open_ftdi();
	pulse_reset();
	return 0;
}