/***************************************************************************
 *   Copyright (C) 02/2008 by Olaf Rempel                                  *
 *   razzor@kopf-tisch.de                                                  *
 *                                                                         *
 *   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; version 2 of the License                *
 *                                                                         *
 *   This program is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
 *   GNU General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
 ***************************************************************************/
#include <stdio.h>
#include <stdint.h>
#include <string.h>
#include "board.h"		// ARRAY_SIZE()
#include "telemetrie.h"
#include "memalloc.h"

/* extern symbols, defined in ldscript */
extern struct tdc_value _tdc_value_table;
extern struct tdc_value _tdc_value_table_end;

/*
 * transmit function
 * returns:
 * -1 : could not sent data (e.g. fifo full)
 * >= 0 : bytes sent
 */
typedef uint32_t (txfunc_t)(struct tdc_pkt_header *head);

/* just eat the packet */
static uint32_t txdummy(struct tdc_pkt_header *head)
{
	return head->size;
}

/* table of txfuncs for routing/forwarding */
static txfunc_t *transmit_table[8] = {
	&txdummy, &txdummy, &txdummy, &txdummy,
	&txdummy, &txdummy, &txdummy, &txdummy,
};

static const struct tdc_hello_reply hello_reply = {
	.cmd = TDC_REPLY | TDC_ADDR1 | TDC_HELLO,
	.size = sizeof(struct tdc_hello_reply),
	.name = "sam7fc-v0.01",
};

void tdc_register_txfunc(uint32_t addr, txfunc_t *txfunc)
{
	if (addr <= ARRAY_SIZE(transmit_table))
		transmit_table[addr] = txfunc;
}

int32_t tdc_transmit(uint32_t addr, struct tdc_pkt_header *head)
{
	if (addr <= ARRAY_SIZE(transmit_table))
		return transmit_table[addr](head);

	return -1;
}

/*
 * send all variable names & flags
 * returns:
 * 0 - success (*id = 0)
 * -1 - not all data was sent, restart request later (*id has restart-point)
 */
int32_t tdc_get_vars(uint32_t *id)
{
	struct tdc_value *value = &_tdc_value_table + *id;

	while (value < &_tdc_value_table_end) {
		uint32_t datalen = strlen(value->name);

		struct tdc_getvars_reply *reply = alloc(sizeof(struct tdc_getvars_reply) + datalen);
		reply->cmd = TDC_REPLY | TDC_ADDR1 | TDC_GETVARS;
		reply->size = sizeof(struct tdc_getvars_reply) + datalen;
		reply->id = *id;
		reply->flags = value->flags;
		memcpy(reply->name, value->name, datalen);

		uint32_t txerror = (tdc_transmit(TDC_ADDR0, ((struct tdc_pkt_header *)reply)) != reply->size);
		free(reply);

		/* transmit fifo is full, remember position (*id) and restart */
		if (txerror)
			return -1;

		(*id)++;
		value++;
	}
	*id = 0;
	return 0;
}

int32_t tdc_get_value(uint32_t id)
{
	struct tdc_value *value = &_tdc_value_table + id;
	uint32_t datalen = value->flags & TDC_SIZEMASK;

	struct tdc_getvalue_reply *reply = alloc(sizeof(struct tdc_getvalue_reply) + datalen);
	reply->cmd = TDC_REPLY | TDC_ADDR1 | TDC_GETVALUE;
	reply->size = sizeof(struct tdc_getvars_reply) + datalen;
	reply->id = id;
	memcpy(reply->data, value->data, datalen);

	int32_t txerror = (tdc_transmit(TDC_ADDR0, ((struct tdc_pkt_header *)reply)) != reply->size);
	free(reply);

	return (txerror) ? -1 : 0;
}

void tdc_set_value(uint32_t id, uint8_t *data)
{
	struct tdc_value *value = &_tdc_value_table + id;
	uint32_t datalen = value->flags & TDC_SIZEMASK;

	// TODO: atomic?
	memcpy(value->data, data, datalen);
}

/*
 * parses tdc data
 * returns:
 * -1 : data too short / error
 * >= 0 : data read, come back if there is more
 */
int32_t tdc_parse_pkt(txfunc_t *txfunc, const uint8_t *data, uint32_t size)
{
	// TODO: use a fifo, with a peek function?

	struct tdc_pkt_header *head = (struct tdc_pkt_header *)data;

	if (size < sizeof(struct tdc_pkt_header))
		return -1;

	/* if it's a hello-request, remember the txfunc as path to the host */
	if ((head->cmd & (TDC_OPCODEMASK & TDC_DIR)) == TDC_HELLO)
		tdc_register_txfunc(TDC_ADDR0, txfunc);

	/* all replys go to the HOST */
	if (head->cmd & TDC_REPLY) {
		// TODO: wrong returncode
		return tdc_transmit(TDC_ADDR0, head);
	}

	/* forward this packet? */
	if ((head->cmd & TDC_ADDRMASK) != TDC_ADDR1) {
		uint32_t addr = (head->cmd & TDC_ADDRMASK) >> 4;
		// TODO: wrong returncode
		return tdc_transmit(addr, head);
	}

	/* parse the packet */
	switch (head->cmd & TDC_OPCODEMASK) {
	/* HELLO from HOST */
	case TDC_HELLO:
		tdc_transmit(TDC_ADDR0, (struct tdc_pkt_header *)&hello_reply);
		break;

	case TDC_GETVARS: {
		static uint32_t i;

		/* tx-fifo is full, complete request later */
		if (tdc_get_vars(&i) == -1)
			return 0;

	}	break;

	case TDC_GETVALUE: {
		struct tdc_getvalue_request *pkt = (struct tdc_getvalue_request *)data;

		/* tx-fifo is full, retry request later */
		if (tdc_get_value(pkt->id) == -1)
			return 0;

	}	break;

	case TDC_SETVALUE: {
		struct tdc_setvalue_request *pkt = (struct tdc_setvalue_request *)data;
		tdc_set_value(pkt->id, pkt->data);
	}	break;

	case TDC_REQVALUES: {
		struct tdc_reqvalues_request *pkt = (struct tdc_reqvalues_request *)data;

	}	break;

	case TDC_TERMINAL:
		// TODO: not possible?
		break;

	case TDC_USERDATA:
		// TODO: currently not used
		break;
	};

	return head->size;
}