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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2008 Arastra, Inc.
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/* This code is based on src/southbridge/intel/esb6300/esb6300_smbus.h */
#include <device/smbus_def.h>
#define SMBHSTSTAT 0x0
#define SMBHSTCTL 0x2
#define SMBHSTCMD 0x3
#define SMBXMITADD 0x4
#define SMBHSTDAT0 0x5
#define SMBHSTDAT1 0x6
#define SMBBLKDAT 0x7
#define SMBTRNSADD 0x9
#define SMBSLVDATA 0xa
#define SMLINK_PIN_CTL 0xe
#define SMBUS_PIN_CTL 0xf
#define SMBSLVCMD 0x11
#define SMBUS_TIMEOUT (100*1000*10)
static void smbus_delay(void)
{
outb(0x80, 0x80);
}
static int smbus_wait_until_ready(u32 smbus_io_base)
{
u32 loops = SMBUS_TIMEOUT;
u8 byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_io_base + SMBHSTSTAT);
} while (byte & 1);
return loops ? 0 : -1;
}
static int smbus_wait_until_done(u32 smbus_io_base)
{
u32 loops = SMBUS_TIMEOUT;
u8 byte;
do {
smbus_delay();
if (--loops == 0)
break;
byte = inb(smbus_io_base + SMBHSTSTAT);
} while ((byte & 1) || (byte & ~((1 << 6)|(1 << 0))) == 0);
return loops ? 0 : -1;
}
static int do_smbus_read_byte(u32 smbus_io_base, u16 device, u8 address)
{
u8 global_status_register;
u8 byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
}
/* setup transaction */
/* disable interrupts */
outb(inb(smbus_io_base + SMBHSTCTL) & (~1), smbus_io_base + SMBHSTCTL);
/* set the device I'm talking too */
outb(((device & 0x7f) << 1) | 1, smbus_io_base + SMBXMITADD);
/* set the command/address... */
outb(address & 0xFF, smbus_io_base + SMBHSTCMD);
/* set up for a byte data read */
outb((inb(smbus_io_base + SMBHSTCTL) & 0xE3) | (0x2 << 2), smbus_io_base + SMBHSTCTL);
/* clear any lingering errors, so the transaction will run */
outb(inb(smbus_io_base + SMBHSTSTAT), smbus_io_base + SMBHSTSTAT);
/* clear the data byte...*/
outb(0, smbus_io_base + SMBHSTDAT0);
/* start the command */
outb((inb(smbus_io_base + SMBHSTCTL) | 0x40), smbus_io_base + SMBHSTCTL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
}
global_status_register = inb(smbus_io_base + SMBHSTSTAT);
/* Ignore the In Use Status... */
global_status_register &= ~(3 << 5);
/* read results of transaction */
byte = inb(smbus_io_base + SMBHSTDAT0);
if (global_status_register != (1 << 1)) {
return SMBUS_ERROR;
}
return byte;
}
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