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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2015 Google Inc. All rights reserved.
*
* 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 "ec.h"
#include "ec_commands.h"
enum {
/* 8-bit access */
ACCESS_TYPE_BYTE = 0x0,
/* 16-bit access */
ACCESS_TYPE_WORD = 0x1,
/* 32-bit access */
ACCESS_TYPE_LONG = 0x2,
/*
* 32-bit access, read or write of MEC_EMI_EC_DATA_B3 causes the
* EC data register to be incremented.
*/
ACCESS_TYPE_LONG_AUTO_INCREMENT = 0x3,
};
/* EMI registers are relative to base */
#define MEC_EMI_BASE 0x800
#define MEC_EMI_HOST_TO_EC (MEC_EMI_BASE + 0)
#define MEC_EMI_EC_TO_HOST (MEC_EMI_BASE + 1)
#define MEC_EMI_EC_ADDRESS_B0 (MEC_EMI_BASE + 2)
#define MEC_EMI_EC_ADDRESS_B1 (MEC_EMI_BASE + 3)
#define MEC_EMI_EC_DATA_B0 (MEC_EMI_BASE + 4)
#define MEC_EMI_EC_DATA_B1 (MEC_EMI_BASE + 5)
#define MEC_EMI_EC_DATA_B2 (MEC_EMI_BASE + 6)
#define MEC_EMI_EC_DATA_B3 (MEC_EMI_BASE + 7)
/*
* cros_ec_lpc_mec_emi_write_address
*
* Initialize EMI read / write at a given address.
*
* @addr: Starting read / write address
* @access_mode: Type of access, typically 32-bit auto-increment
*/
static void mec_emi_write_address(u16 addr, u8 access_mode)
{
/* Address relative to start of EMI range */
addr -= MEC_EMI_RANGE_START;
outb((addr & 0xfc) | access_mode, MEC_EMI_EC_ADDRESS_B0);
outb((addr >> 8) & 0x7f, MEC_EMI_EC_ADDRESS_B1);
}
/*
* mec_io_bytes - Read / write bytes to MEC EMI port
*
* @write: 1 on write operation, 0 on read
* @port: Base read / write address
* @length: Number of bytes to read / write
* @buf: Destination / source buffer
* @csum: Optional parameter, sums data transferred
*
*/
void mec_io_bytes(int write, u16 port, unsigned int length, u8 *buf, u8 *csum)
{
int i = 0;
int io_addr;
u8 access_mode, new_access_mode;
if (length == 0)
return;
/*
* Long access cannot be used on misaligned data since reading B0 loads
* the data register and writing B3 flushes it.
*/
if ((port & 0x3) || (length < 4))
access_mode = ACCESS_TYPE_BYTE;
else
access_mode = ACCESS_TYPE_LONG_AUTO_INCREMENT;
/* Initialize I/O at desired address */
mec_emi_write_address(port, access_mode);
/* Skip bytes in case of misaligned port */
io_addr = MEC_EMI_EC_DATA_B0 + (port & 0x3);
while (i < length) {
while (io_addr <= MEC_EMI_EC_DATA_B3) {
if (write)
outb(buf[i], io_addr++);
else
buf[i] = inb(io_addr++);
if (csum)
*csum += buf[i];
port++;
/* Extra bounds check in case of misaligned length */
if (++i == length)
return;
}
/*
* Use long auto-increment access except for misaligned write,
* since writing B3 triggers the flush.
*/
if (length - i < 4 && write)
new_access_mode = ACCESS_TYPE_BYTE;
else
new_access_mode = ACCESS_TYPE_LONG_AUTO_INCREMENT;
if (new_access_mode != access_mode ||
access_mode != ACCESS_TYPE_LONG_AUTO_INCREMENT) {
access_mode = new_access_mode;
mec_emi_write_address(port, access_mode);
}
/* Access [B0, B3] on each loop pass */
io_addr = MEC_EMI_EC_DATA_B0;
}
}
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