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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2005 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; 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 0x0
#define SMBSLVSTAT 0x1
#define SMBHSTCTRL 0x2
#define SMBHSTCMD 0x3
#define SMBHSTADDR 0x4
#define SMBHSTDAT0 0x5
#define SMBHSTDAT1 0x6
#define SMBHSTBLKDAT 0x7
#define SMBSLVCTRL 0x8
#define SMBSLVCMD_SHADOW 0x9
#define SMBSLVEVT 0xa
#define SMBSLVDAT 0xc
/* 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_ready(unsigned smbus_io_base)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
val = inb(smbus_io_base + SMBHSTSTAT);
val &= 0x1f;
if (val == 0) { // ready now
return 0;
}
outb(val, smbus_io_base + SMBHSTSTAT);
} while (--loops);
return -2; // time out
}
static int smbus_wait_until_done(unsigned smbus_io_base)
{
unsigned long loops;
loops = SMBUS_TIMEOUT;
do {
unsigned char val;
val = inb(smbus_io_base + SMBHSTSTAT);
val &= 0x1f; // mask off reserved bits
if (val & 0x1c) {
return -5; // error
}
if (val == 0x02) {
outb(val, smbus_io_base + SMBHSTSTAT); // clear status
return 0; //
}
} while (--loops);
return -3; // timeout
}
static int do_smbus_recv_byte(unsigned smbus_io_base, unsigned device)
{
uint8_t byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return -2; // not ready
}
/* set the device I'm talking to */
outb(((device & 0x7f) << 1)|1 , smbus_io_base + SMBHSTADDR);
byte = inb(smbus_io_base + SMBHSTCTRL);
byte &= 0xe3; // Clear [4:2]
byte |= (1<<2) | (1<<6); // Byte data read/write command, start the command
outb(byte, smbus_io_base + SMBHSTCTRL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3; // timeout or error
}
/* read results of transaction */
byte = inb(smbus_io_base + SMBHSTCMD);
return byte;
}
static int do_smbus_send_byte(unsigned smbus_io_base, unsigned device, unsigned char val)
{
uint8_t byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return -2; // not ready
}
/* set the command... */
outb(val, smbus_io_base + SMBHSTCMD);
/* set the device I'm talking to */
outb(((device & 0x7f) << 1)|0 , smbus_io_base + SMBHSTADDR);
byte = inb(smbus_io_base + SMBHSTCTRL);
byte &= 0xe3; // Clear [4:2]
byte |= (1<<2) | (1<<6); // Byte data read/write command, start the command
outb(byte, smbus_io_base + SMBHSTCTRL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3; // timeout or error
}
return 0;
}
static int do_smbus_read_byte(unsigned smbus_io_base, unsigned device, unsigned address)
{
uint8_t byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return -2; // not ready
}
/* set the command/address... */
outb(address & 0xff, smbus_io_base + SMBHSTCMD);
/* set the device I'm talking to */
outb(((device & 0x7f) << 1)|1 , smbus_io_base + SMBHSTADDR);
byte = inb(smbus_io_base + SMBHSTCTRL);
byte &= 0xe3; // Clear [4:2]
byte |= (1<<3) | (1<<6); // Byte data read/write command, start the command
outb(byte, smbus_io_base + SMBHSTCTRL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3; // timeout or error
}
/* read results of transaction */
byte = inb(smbus_io_base + SMBHSTDAT0);
return byte;
}
static int do_smbus_write_byte(unsigned smbus_io_base, unsigned device, unsigned address, unsigned char val)
{
uint8_t byte;
if (smbus_wait_until_ready(smbus_io_base) < 0) {
return -2; // not ready
}
/* set the command/address... */
outb(address & 0xff, smbus_io_base + SMBHSTCMD);
/* set the device I'm talking to */
outb(((device & 0x7f) << 1)|0 , smbus_io_base + SMBHSTADDR);
/* output value */
outb(val, smbus_io_base + SMBHSTDAT0);
byte = inb(smbus_io_base + SMBHSTCTRL);
byte &= 0xe3; // Clear [4:2]
byte |= (1<<3) | (1<<6); // Byte data read/write command, start the command
outb(byte, smbus_io_base + SMBHSTCTRL);
/* poll for transaction completion */
if (smbus_wait_until_done(smbus_io_base) < 0) {
return -3; // timeout or error
}
return 0;
}
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