/* * 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> /** * \brief printk macro for SMBus debugging */ #if IS_ENABLED(CONFIG_DEBUG_SMBUS) #define printsmbus(x, ...) printk(BIOS_DEBUG, x, ##__VA_ARGS__) #else #define printsmbus(x, ...) #endif u32 smbus_get_device(void); void smbus_reset(u32 smbus_dev); int smbus_print_error(u32 smbus_dev, u8 host_status, int loops); int smbus_is_busy(u32 smbus_dev); int smbus_wait_until_ready(u32 smbus_dev); u8 smbus_read_byte(u32 smbus_dev, u8 addr, u8 offset); void smbus_delay(void); #endif /* DEVICE_EARLY_SMBUS_H */