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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2011 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.
*/
/**
* @file device/early_smbus.h
*
* This file defines a common API for accessing the SMBus during early
* initialization. It defines the prototypes for common SMBus functions. The
* actual implementations are hardware-dependent.
*
* The first parameter of all SMBus functions take a u32 value smbus_dev which
* represents some information on how to access the device, and is
* implementation defined. Usually, it just contains the IO base for the smbus.
* To get this argument @ref smbus_get_device() can be used.
*
* The header only defines the prototypes. Several steps are needed to use
* these:
*
* 1. Include this header
* @code{.c}
* #include <device/early_smbus.h>
* @endcode
*
* 2. Implement early_smbus.c for the hardware, or find a compatible
* implementation.
*
* 3. Link against the file that implements these functions. In the Makefile.inc
* of the chipset, add:
* @code
* romstage-y += ./path/to/early_smbus.c
* @endcode
*/
#ifndef DEVICE_EARLY_SMBUS_H
#define DEVICE_EARLY_SMBUS_H
#include <stdint.h>
u16 smbus_read_word(u32 smbus_dev, u8 addr, u8 offset);
u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset);
u8 smbus_write_byte(u32 smbus_dev, u8 addr, u8 offset, u8 value);
#endif /* DEVICE_EARLY_SMBUS_H */
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