/* 
 * Copyright 2010 Stefan Lankes, 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.
 */

/**
 * @author Stefan Lankes
 * @file arch/x86/include/asm/io.h
 * @brief Functions related to processor IO
 *
 * This file contains inline functions for processor IO operations.
 */

#ifndef __ARCH_IO_H__
#define __ARCH_IO_H__

#ifdef __cplusplus
extern "C" {
#endif

#ifndef CMOS_PORT_ADDRESS
#define CMOS_PORT_ADDRESS	0x70
#endif
#ifndef CMOS_PORT_DATA
#define CMOS_PORT_DATA		0x71
#endif

/** @brief Read a byte from an IO port
 *
 * @param _port The port you want to read from
 * @return The value which reads out from this port
 */
inline static unsigned char inportb(unsigned short _port) {
	unsigned char rv;
	asm volatile("inb %1, %0":"=a"(rv):"dN"(_port));
	return rv;
} 

/** @brief Read a word (2 byte) from an IO port
 *
 * @param _port The port you want to read from
 * @return The value which reads out from this port
 */
inline static unsigned short inportw(unsigned short _port) {
	unsigned short rv;
	asm volatile("inw %1, %0":"=a"(rv):"dN"(_port));
	return rv;
}

/** @brief Read a double word (4 byte) from an IO port
 *
 * @param _port The port you want to read from
 * @return The value which reads out from this port
 */
inline static unsigned int inportl(unsigned short _port) {
	unsigned int rv;
	asm volatile("inl %1, %0":"=a"(rv):"dN"(_port));
	return rv;
}

/** @brief Write a byte to an IO port
 *
 * @param _port The port you want to write to
 * @param _data the 1 byte value you want to write
 */
inline static void outportb(unsigned short _port, unsigned char _data) {
	asm volatile("outb %1, %0"::"dN"(_port), "a"(_data));
}

/** @brief Write a word (2 bytes) to an IO port
 *
 * @param _port The port you want to write to
 * @param _data the 2 byte value you want to write
 */
inline static void outportw(unsigned short _port, unsigned short _data) {
	asm volatile("outw %1, %0"::"dN"(_port), "a"(_data));
}

/** @brief Write a double word (4 bytes) to an IO port
 *
 * @param _port The port you want to write to
 * @param _data the 4 byte value you want to write
 */
inline static void outportl(unsigned short _port, unsigned int _data)
{
	 asm volatile("outl %1, %0"::"dN"(_port), "a"(_data));
}

inline static void uart_putchar(unsigned char _data)
{
	outportb(0x2F8, _data);
}

/**
 * read a byte from CMOS
 *  @param offset CMOS offset
 *  @return value you want to read
 */
inline static uint8_t cmos_read(uint8_t offset)
{
	outportb(CMOS_PORT_ADDRESS, offset);
	return inportb(CMOS_PORT_DATA);
}
 
/**
 * write a byte in CMOS
 *  @param offset CMOS offset
 *  @param val the value you want wto write
 */
inline static void cmos_write(uint8_t offset, uint8_t val)
{
	outportb(CMOS_PORT_ADDRESS, offset);
	outportb(CMOS_PORT_DATA, val);
}

#ifdef __cplusplus
}
#endif

#endif