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| -rw-r--r-- | src/include/device/early_smbus.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/include/device/early_smbus.h b/src/include/device/early_smbus.h new file mode 100644 index 0000000000..77c9078a1b --- /dev/null +++ b/src/include/device/early_smbus.h @@ -0,0 +1,73 @@ +/* + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +/** + * @file 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 defined(CONFIG_DEBUG_SMBUS_SETUP) && (CONFIG_DEBUG_SMBUS_SETUP) +#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 */ |