/* * This file is part of the coreboot project. * * Copyright (C) 2004 Tyan Computer * Written by Yinghai Lu <yhlu@tyan.com> for Tyan Computer. * Copyright (C) 2006,2007 AMD * Written by Yinghai Lu <yinghai.lu@amd.com> for AMD. * * 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 <device/smbus_def.h> #define SMBHSTSTAT 0x1 #define SMBHSTPRTCL 0x0 #define SMBHSTCMD 0x3 #define SMBXMITADD 0x2 #define SMBHSTDAT0 0x4 #define SMBHSTDAT1 0x5 /* Between 1-10 seconds, We should never timeout normally * Longer than this is just painful when a timeout condition occurs. */ #define SMBUS_TIMEOUT (100*1000*10) static inline void smbus_delay(void) { outb(0x80, 0x80); } static int smbus_wait_until_done(unsigned smbus_io_base) { unsigned long loops; loops = SMBUS_TIMEOUT; do { unsigned char val; smbus_delay(); val = inb(smbus_io_base + SMBHSTSTAT); if ( (val & 0xff) != 0) { return 0; } } while (--loops); return -3; } static int do_smbus_recv_byte(unsigned smbus_io_base, unsigned device) { unsigned char global_status_register; unsigned char byte; /* set the device I'm talking too */ outb(((device & 0x7f) << 1)|1 , smbus_io_base + SMBXMITADD); smbus_delay(); /* byte data recv */ outb(0x05, smbus_io_base + SMBHSTPRTCL); smbus_delay(); /* poll for transaction completion */ if (smbus_wait_until_done(smbus_io_base) < 0) { return -3; } global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */ /* read results of transaction */ byte = inb(smbus_io_base + SMBHSTCMD); if (global_status_register != 0x80) { // lose check, otherwise it should be 0 return -1; } return byte; } static int do_smbus_send_byte(unsigned smbus_io_base, unsigned device, unsigned char val) { unsigned global_status_register; outb(val, smbus_io_base + SMBHSTDAT0); smbus_delay(); /* set the command... */ outb(val, smbus_io_base + SMBHSTCMD); smbus_delay(); /* set the device I'm talking too */ outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBXMITADD); smbus_delay(); /* set up for a byte data write */ outb(0x04, smbus_io_base + SMBHSTPRTCL); smbus_delay(); /* poll for transaction completion */ if (smbus_wait_until_done(smbus_io_base) < 0) { return -3; } global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */ if (global_status_register != 0x80) { return -1; } return 0; } static int do_smbus_read_byte(unsigned smbus_io_base, unsigned device, unsigned address) { unsigned char global_status_register; unsigned char byte; /* set the device I'm talking too */ outb(((device & 0x7f) << 1)|1 , smbus_io_base + SMBXMITADD); smbus_delay(); /* set the command/address... */ outb(address & 0xff, smbus_io_base + SMBHSTCMD); smbus_delay(); /* byte data read */ outb(0x07, smbus_io_base + SMBHSTPRTCL); smbus_delay(); /* poll for transaction completion */ if (smbus_wait_until_done(smbus_io_base) < 0) { return -3; } global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */ /* read results of transaction */ byte = inb(smbus_io_base + SMBHSTDAT0); if (global_status_register != 0x80) { // lose check, otherwise it should be 0 return -1; } return byte; } static int do_smbus_write_byte(unsigned smbus_io_base, unsigned device, unsigned address, unsigned char val) { unsigned global_status_register; outb(val, smbus_io_base + SMBHSTDAT0); smbus_delay(); /* set the device I'm talking too */ outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBXMITADD); smbus_delay(); outb(address & 0xff, smbus_io_base + SMBHSTCMD); smbus_delay(); /* set up for a byte data write */ outb(0x06, smbus_io_base + SMBHSTPRTCL); smbus_delay(); /* poll for transaction completion */ if (smbus_wait_until_done(smbus_io_base) < 0) { return -3; } global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80; /* lose check */ if (global_status_register != 0x80) { return -1; } return 0; }