/*
 *   AVR emulator
 *   Ports
 *
 *   Copyright (C) 2007 Michael Buesch <mb@bu3sch.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; either version 2
 *   of the License, or (at your option) any later version.
 *
 *   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.
 */

#include "ports.h"
#include "memory.h"
#include "util.h"

#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <pthread.h>


enum port_voltage_level {
	PORT_VOLT_TRISTATE = 0,
	PORT_VOLT_HIGH,
	PORT_VOLT_LOW,
};

struct port {
	/* Spinlock for this port. */
	pthread_spinlock_t lock;
	/* Data direction of the individual port bits.
	 * Bit-set means output. */
	uint8_t ddr;
	/* PORTX register status. */
	uint8_t port;
	/* Voltage level status on the physical pin. */
	enum port_voltage_level levels[8];
};


static struct port portb;
static struct port portc;
static struct port portd;


static void port_read(struct port *port, uint16_t mem_offset)
{
	pthread_spin_lock(&port->lock);
	memory.ram[mem_offset] = port->port;
	pthread_spin_lock(&port->lock);
}

static void port_write(struct port *port, uint8_t new_val)
{
	pthread_spin_lock(&port->lock);
	port->port = new_val;
	//TODO
	pthread_spin_unlock(&port->lock);
}

static void ddr_read(struct port *port, uint16_t mem_offset)
{
	pthread_spin_lock(&port->lock);
	memory.ram[mem_offset] = port->ddr;
	pthread_spin_unlock(&port->lock);
}

static void ddr_write(struct port *port, uint8_t new_val)
{
	pthread_spin_lock(&port->lock);
	port->ddr = new_val;
	pthread_spin_unlock(&port->lock);
}

static void pin_read(struct port *port, uint16_t mem_offset)
{
	int i;
	uint8_t mask, data = 0;

	pthread_spin_lock(&port->lock);
	for (i = 0; i < 8; i++) {
		mask = (1 << i);
		if (unlikely(port->ddr & mask)) {
			/* This is an output pin. */
			if (port->port & mask)
				data |= mask;
		} else {
			/* This is an input pin. */
			switch (port->levels[i]) {
			case PORT_VOLT_TRISTATE:
				if (port->port & mask)
					data |= mask;
				break;
			case PORT_VOLT_HIGH:
				data |= mask;
				break;
			case PORT_VOLT_LOW:
				break;
			}
		}
	}
	memory.ram[mem_offset] = data;
	pthread_spin_lock(&port->lock);
}

static void io_portb_write(uint16_t mem_offset, uint8_t old_val, uint8_t new_val)
{
	port_write(&portb, new_val);
}

static void io_portc_write(uint16_t mem_offset, uint8_t old_val, uint8_t new_val)
{
	port_write(&portc, new_val);
}

static void io_portd_write(uint16_t mem_offset, uint8_t old_val, uint8_t new_val)
{
	port_write(&portd, new_val);
}

static void io_ddrb_write(uint16_t mem_offset, uint8_t old_val, uint8_t new_val)
{
	ddr_write(&portb, new_val);
}

static void io_ddrc_write(uint16_t mem_offset, uint8_t old_val, uint8_t new_val)
{
	ddr_write(&portc, new_val);
}

static void io_ddrd_write(uint16_t mem_offset, uint8_t old_val, uint8_t new_val)
{
	ddr_write(&portd, new_val);
}

static void io_portb_read(uint16_t mem_offset)
{
	port_read(&portb, mem_offset);
}

static void io_portc_read(uint16_t mem_offset)
{
	port_read(&portc, mem_offset);
}

static void io_portd_read(uint16_t mem_offset)
{
	port_read(&portd, mem_offset);
}

static void io_pinb_read(uint16_t mem_offset)
{
	pin_read(&portb, mem_offset);
}

static void io_pinc_read(uint16_t mem_offset)
{
	pin_read(&portc, mem_offset);
}

static void io_pind_read(uint16_t mem_offset)
{
	pin_read(&portd, mem_offset);
}

static void io_ddrb_read(uint16_t mem_offset)
{
	ddr_read(&portb, mem_offset);
}

static void io_ddrc_read(uint16_t mem_offset)
{
	ddr_read(&portc, mem_offset);
}

static void io_ddrd_read(uint16_t mem_offset)
{
	ddr_read(&portd, mem_offset);
}

static int port_init(struct port *port)
{
	int err;

	memset(port, 0, sizeof(struct port));
	err = pthread_spin_init(&port->lock, 0);
	if (err) {
		fprintf(stderr, "Ports: Failed to init spinlock\n");
		return err;
	}

	return 0;
}

static void port_cleanup(struct port *port)
{
	pthread_spin_destroy(&port->lock);
}

int avrdev_ports_init(void)
{
	int err;

	err = port_init(&portb);
	if (err)
		goto error;
	err = port_init(&portc);
	if (err)
		goto err_cleanup_portb;
	err = port_init(&portd);
	if (err)
		goto err_cleanup_portc;

	err = 0;
	err |= register_io_write_handler(io_portb_write, IO_PORTB);
	err |= register_io_write_handler(io_portc_write, IO_PORTC);
	err |= register_io_write_handler(io_portd_write, IO_PORTD);
	err |= register_io_write_handler(io_ddrb_write, IO_DDRB);
	err |= register_io_write_handler(io_ddrc_write, IO_DDRC);
	err |= register_io_write_handler(io_ddrd_write, IO_DDRD);
	err |= register_io_read_handler(io_portb_read, IO_PORTB);
	err |= register_io_read_handler(io_portc_read, IO_PORTC);
	err |= register_io_read_handler(io_portd_read, IO_PORTD);
	err |= register_io_read_handler(io_pinb_read, IO_PINB);
	err |= register_io_read_handler(io_pinc_read, IO_PINC);
	err |= register_io_read_handler(io_pind_read, IO_PIND);
	err |= register_io_read_handler(io_ddrb_read, IO_DDRB);
	err |= register_io_read_handler(io_ddrc_read, IO_DDRC);
	err |= register_io_read_handler(io_ddrd_read, IO_DDRD);
	if (err) {
		err = -ENOMEM;
		fprintf(stderr, "Failed to register port handlers.\n");
		goto err_cleanup_portd;
	}

	return 0;

err_cleanup_portd:
	port_cleanup(&portd);
err_cleanup_portc:
	port_cleanup(&portc);
err_cleanup_portb:
	port_cleanup(&portb);
error:
	return err;
}

void avrdev_ports_exit(void)
{//FIXME somebody must call me
	port_cleanup(&portd);
	port_cleanup(&portc);
	port_cleanup(&portb);
}