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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2013 Alexandru Gagniuc <mr.nuke.me@gmail.com>
*
* 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 <arch/io.h>
#include <device/early_smbus.h>
#include "via_early_smbus.h"
/**
* \brief Read a byte from the SMBus.
*
* @param smbus_dev The base SMBus IO port
* @param addr The address location of the DIMM on the SMBus.
* @param offset The offset the data is located at.
*/
u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset)
{
u8 val;
/* Initialize SMBus sequence */
smbus_reset(smbus_dev);
/* Clear host data port. */
outb(0x00, SMBHSTDAT0(smbus_dev));
smbus_wait_until_ready(smbus_dev);
/* Actual addr to reg format. */
addr = (addr << 1);
addr |= 1; /* read command */
outb(addr, SMBXMITADD(smbus_dev));
outb(offset, SMBHSTCMD(smbus_dev));
/* Start transaction, byte data read. */
outb(0x48, SMBHSTCTL(smbus_dev));
smbus_wait_until_ready(smbus_dev);
val = inb(SMBHSTDAT0(smbus_dev));
return val;
}
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