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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2019 Evgeny Zinoviev <me@ch1p.io>
*
* SMC interacting code is based on applesmc linux driver by:
* Copyright (C) 2007 Nicolas Boichat <nicolas@boichat.ch>
* Copyright (C) 2010 Henrik Rydberg <rydberg@euromail.se>
*
* 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 <stdlib.h>
#include <sys/io.h>
#include <errno.h>
#include <stdio.h>
#include "smc.h"
/*
* wait_read - Wait for a byte to appear on SMC port. Callers must
* hold applesmc_lock.
*/
int wait_read(void)
{
uint8_t status;
int us;
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
usleep(us);
status = inb(APPLESMC_CMD_PORT);
/* read: wait for smc to settle */
if (status & 0x01)
return 0;
}
fprintf(stderr, "%s() fail: 0x%02x\n", __func__, status);
return -EIO;
}
/*
* send_byte - Write to SMC port, retrying when necessary. Callers
* must hold applesmc_lock.
*/
int send_byte(uint8_t cmd, uint16_t port)
{
uint8_t status;
int us;
outb(cmd, port);
for (us = APPLESMC_MIN_WAIT; us < APPLESMC_MAX_WAIT; us <<= 1) {
usleep(us);
status = inb(APPLESMC_CMD_PORT);
/* write: wait for smc to settle */
if (status & 0x02)
continue;
/* ready: cmd accepted, return */
if (status & 0x04)
return 0;
/* timeout: give up */
if (us << 1 == APPLESMC_MAX_WAIT)
break;
/* busy: long wait and resend */
usleep(APPLESMC_RETRY_WAIT);
outb(cmd, port);
}
fprintf(stderr, "%s(0x%02x, 0x%04x) fail: 0x%02x\n",
__func__, cmd, port, status);
return -EIO;
}
int send_command(uint8_t cmd)
{
return send_byte(cmd, APPLESMC_CMD_PORT);
}
int send_argument(const char *key)
{
int i;
for (i = 0; i < 4; i++)
if (send_byte(key[i], APPLESMC_DATA_PORT))
return -EIO;
return 0;
}
int read_smc(uint8_t cmd, const char *key, uint8_t *buffer, uint8_t len)
{
uint8_t status, data = 0;
int i;
if (send_command(cmd) || send_argument(key)) {
fprintf(stderr, "%.4s: read arg fail\n", key);
return -EIO;
}
/* This has no effect on newer (2012) SMCs */
if (send_byte(len, APPLESMC_DATA_PORT)) {
fprintf(stderr, "%.4s: read len fail\n", key);
return -EIO;
}
for (i = 0; i < len; i++) {
if (wait_read()) {
fprintf(stderr, "%.4s: read data[%d] fail\n", key, i);
return -EIO;
}
buffer[i] = inb(APPLESMC_DATA_PORT);
}
/* Read the data port until bit0 is cleared */
for (i = 0; i < 16; i++) {
usleep(APPLESMC_MIN_WAIT);
status = inb(APPLESMC_CMD_PORT);
if (!(status & 0x01))
break;
data = inb(APPLESMC_DATA_PORT);
}
if (i)
fprintf(stderr, "flushed %d bytes, last value is: %d\n",
i, data);
return 0;
}
int write_smc(uint8_t cmd, const char *key, const uint8_t *buffer, uint8_t len)
{
int i;
if (send_command(cmd) || send_argument(key)) {
fprintf(stderr, "%s: write arg fail\n", key);
return -EIO;
}
if (send_byte(len, APPLESMC_DATA_PORT)) {
fprintf(stderr, "%.4s: write len fail\n", key);
return -EIO;
}
for (i = 0; i < len; i++) {
if (send_byte(buffer[i], APPLESMC_DATA_PORT)) {
fprintf(stderr, "%s: write data fail\n", key);
return -EIO;
}
}
return 0;
}
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