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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2017 Intel Corporation.
*
* 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 <arch/io.h>
#include <device/smbus_def.h>
#include <timer.h>
#include "smbuslib.h"
static int smbus_wait_till_ready(u16 smbus_base)
{
struct stopwatch sw;
unsigned char byte;
stopwatch_init_msecs_expire(&sw, SMBUS_TIMEOUT);
do {
byte = inb(smbus_base + SMBHSTSTAT);
if (!(byte & 1))
return 0;
} while (!stopwatch_expired(&sw));
return -1;
}
static int smbus_wait_till_done(u16 smbus_base)
{
struct stopwatch sw;
unsigned char byte;
stopwatch_init_msecs_expire(&sw, SMBUS_TIMEOUT);
do {
byte = inb(smbus_base + SMBHSTSTAT);
if (!((byte & 1) || (byte & ~((1 << 6) | (1 << 0))) == 0))
return 0;
} while (!stopwatch_expired(&sw));
return -1;
}
int smbus_read8(unsigned int smbus_base, unsigned int device,
unsigned int address)
{
unsigned char global_status_register;
unsigned char byte;
if (smbus_wait_till_ready(smbus_base) < 0)
return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
/* Setup transaction */
/* Disable interrupts */
outb(inb(smbus_base + SMBHSTCTL) & (~1), smbus_base + SMBHSTCTL);
/* Set the device I'm talking too */
outb(((device & 0x7f) << 1) | 1, smbus_base + SMBXMITADD);
/* Set the command/address... */
outb(address & 0xff, smbus_base + SMBHSTCMD);
/* Set up for a byte data read */
outb((inb(smbus_base + SMBHSTCTL) & 0xe3) | (0x2 << 2),
(smbus_base + SMBHSTCTL));
/* Clear any lingering errors, so the transaction will run */
outb(inb(smbus_base + SMBHSTSTAT), smbus_base + SMBHSTSTAT);
/* Clear the data byte... */
outb(0, smbus_base + SMBHSTDAT0);
/* Start the command */
outb((inb(smbus_base + SMBHSTCTL) | 0x40),
smbus_base + SMBHSTCTL);
/* Poll for transaction completion */
if (smbus_wait_till_done(smbus_base) < 0)
return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
global_status_register = inb(smbus_base + SMBHSTSTAT);
/* Ignore the "In Use" status... */
global_status_register &= ~(3 << 5);
/* Read results of transaction */
byte = inb(smbus_base + SMBHSTDAT0);
if (global_status_register != (1 << 1))
return SMBUS_ERROR;
return byte;
}
int smbus_write8(unsigned int smbus_base, unsigned int device,
unsigned int address, unsigned int data)
{
unsigned char global_status_register;
if (smbus_wait_till_ready(smbus_base) < 0)
return SMBUS_WAIT_UNTIL_READY_TIMEOUT;
/* Setup transaction */
/* Disable interrupts */
outb(inb(smbus_base + SMBHSTCTL) & (~1), smbus_base + SMBHSTCTL);
/* Set the device I'm talking too */
outb(((device & 0x7f) << 1) & ~0x01, smbus_base + SMBXMITADD);
/* Set the command/address... */
outb(address & 0xff, smbus_base + SMBHSTCMD);
/* Set up for a byte data read */
outb((inb(smbus_base + SMBHSTCTL) & 0xe3) | (0x2 << 2),
(smbus_base + SMBHSTCTL));
/* Clear any lingering errors, so the transaction will run */
outb(inb(smbus_base + SMBHSTSTAT), smbus_base + SMBHSTSTAT);
/* Clear the data byte... */
outb(data, smbus_base + SMBHSTDAT0);
/* Start the command */
outb((inb(smbus_base + SMBHSTCTL) | 0x40),
smbus_base + SMBHSTCTL);
/* Poll for transaction completion */
if (smbus_wait_till_done(smbus_base) < 0)
return SMBUS_WAIT_UNTIL_DONE_TIMEOUT;
global_status_register = inb(smbus_base + SMBHSTSTAT);
/* Ignore the "In Use" status... */
global_status_register &= ~(3 << 5);
/* Read results of transaction */
if (global_status_register != (1 << 1))
return SMBUS_ERROR;
return 0;
}
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