/* 
 * Copyright 2011 Steffen Vogel, Chair for Operating Systems,
 *                               RWTH Aachen University
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * This file is part of MetalSVM.
 */

#include <asm/uart.h>
#include <asm/io.h>

/**
 * @author Steffen Vogel <steffen.vogel@rwth-aachen.de>
 */

static inline int is_transmit_empty()
{
	return inportb(UART_PORT + 5) & 0x20;
}

static inline int received()
{
	return inportb(UART_PORT + 5) & 1;
}

void uart_init()
{
	outportb(UART_PORT + 1, 0x00);	// Disable all interrupts
	outportb(UART_PORT + 3, 0x80);	// Enable DLAB (set baud rate divisor)
	outportb(UART_PORT + 0, 0x0C);	// Set divisor to 12 (lo byte) 9600 baud
	outportb(UART_PORT + 1, 0x00);	//                   (hi byte)
	outportb(UART_PORT + 3, 0x03);	// 8 bits, no parity, one stop bit (8N1)
	outportb(UART_PORT + 2, 0xC7);	// Enable FIFO, clear them, with 14-byte threshold
	outportb(UART_PORT + 4, 0x0B);	// IRQs enabled, RTS/DSR set
}

char uart_getchar()
{
	while (!received());
	return inportb(UART_PORT);
}

void uart_putchar(char chr)
{
	while (!is_transmit_empty());
	outportb(UART_PORT, chr);
}

void uart_puts(const char* str)
{
	while (*str) uart_putchar(*(str++));
}

int uart_gets(char* str, size_t len)
{
	size_t ret = 0;
	while (ret < len)
		str[ret] = uart_getchar();

	return ret;
}