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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2004 Tyan Computer
* Written by Yinghai Lu <yhlu@tyan.com> for Tyan Computer.
*
* 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; version 2 of the License.
*
* 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;
}
#ifndef __PRE_RAM__
static int do_smbus_recv_byte(unsigned smbus_io_base, unsigned device)
{
unsigned char global_status_register, byte;
/* Set the device I'm talking to. */
outb(((device & 0x7f) << 1) | 1, smbus_io_base + SMBXMITADD);
smbus_delay();
/* Set the command/address. */
outb(0, smbus_io_base + SMBHSTCMD);
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;
/* Lose check. */
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80;
/* Read results of transaction. */
byte = inb(smbus_io_base + SMBHSTDAT0);
/* Lose check, otherwise it should be 0. */
if (global_status_register != 0x80)
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 device I'm talking to. */
outb(((device & 0x7f) << 1) | 0, smbus_io_base + SMBXMITADD);
smbus_delay();
outb(0, smbus_io_base + SMBHSTCMD);
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;
/* Lose check. */
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80;
if (global_status_register != 0x80)
return -1;
return 0;
}
#endif
static int do_smbus_read_byte(unsigned smbus_io_base, unsigned device,
unsigned address)
{
unsigned char global_status_register, byte;
/* Set the device I'm talking to. */
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;
/* Lose check. */
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80;
/* Read results of transaction. */
byte = inb(smbus_io_base + SMBHSTDAT0);
/* Lose check, otherwise it should be 0. */
if (global_status_register != 0x80)
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 to. */
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;
/* Lose check. */
global_status_register = inb(smbus_io_base + SMBHSTSTAT) & 0x80;
if (global_status_register != 0x80)
return -1;
return 0;
}
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