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/*
* This file is part of the coreboot project.
*
* Copyright (C) 2013 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.
*
* 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
*/
#include <arch/io.h>
#include <console/console.h>
#include <delay.h>
#include <device/i2c.h>
#include <stdint.h>
#include <string.h>
#include "ec.h"
#include "ec_commands.h"
/* Command (host->device) format for I2C:
* uint8_t version, cmd, len, data[len], checksum;
*
* Response (device->host) format for I2C:
* uint8_t response, len, data[len], checksum;
*
* Note the location of checksum is different from LPC protocol.
*
* The length is 8 bit so maximum data size is 0xff.
* Any I2C command should fit in 0xff + 4 bytes, and max response length
* is 0xff + 3 bytes.
*/
#define MAX_I2C_DATA_SIZE (0xff)
typedef struct {
uint8_t version;
uint8_t command;
uint8_t length;
uint8_t data[MAX_I2C_DATA_SIZE + 1];
} EcCommandI2c;
typedef struct {
uint8_t response;
uint8_t length;
uint8_t data[MAX_I2C_DATA_SIZE + 1];
} EcResponseI2c;
static inline void i2c_dump(int bus, int chip, const uint8_t *data, size_t size)
{
#ifdef TRACE_CHROMEEC
printk(BIOS_INFO, "i2c: bus=%d, chip=%#x, size=%d, data: ", bus, chip,
size);
while (size-- > 0) {
printk(BIOS_INFO, "%02X ", *data++);
}
printk(BIOS_INFO, "\n");
#endif
}
static int ec_verify_checksum(const EcResponseI2c *resp)
{
size_t size = sizeof(*resp) - sizeof(resp->data) + resp->length;
uint8_t calculated = google_chromeec_calc_checksum(
(const uint8_t *)resp, size);
uint8_t received = resp->data[resp->length];
if (calculated != received) {
printk(BIOS_ERR, "%s: Unmatch (rx: %#02x, calc: %#02x)\n",
__func__, received, calculated);
return 0;
}
return 1;
}
static void ec_fill_checksum(EcCommandI2c *cmd)
{
size_t size = sizeof(*cmd) - sizeof(cmd->data) + cmd->length;
cmd->data[cmd->length] = google_chromeec_calc_checksum(
(const uint8_t *)cmd, size);
}
int google_chromeec_command(struct chromeec_command *cec_command)
{
EcCommandI2c cmd;
EcResponseI2c resp;
int bus = CONFIG_EC_GOOGLE_CHROMEEC_I2C_BUS;
int chip = CONFIG_EC_GOOGLE_CHROMEEC_I2C_CHIP;
size_t size_i2c_cmd = (sizeof(cmd) - sizeof(cmd.data) +
cec_command->cmd_size_in + 1),
size_i2c_resp = (sizeof(resp) - sizeof(resp.data) +
cec_command->cmd_size_out + 1);
if (cec_command->cmd_size_in > MAX_I2C_DATA_SIZE ||
cec_command->cmd_size_out > MAX_I2C_DATA_SIZE) {
printk(BIOS_ERR, "%s: Command data size too large (%d,%d)\n",
__func__, cec_command->cmd_size_in,
cec_command->cmd_size_out);
cec_command->cmd_code = EC_RES_INVALID_PARAM;
return 1;
}
/* Construct command. */
cmd.version = EC_CMD_VERSION0 + cec_command->cmd_version;
cmd.command = cec_command->cmd_code;
cmd.length = cec_command->cmd_size_in;
memcpy(cmd.data, cec_command->cmd_data_in, cmd.length);
ec_fill_checksum(&cmd);
/* Start I2C communication */
i2c_dump(bus, chip, (const uint8_t *)&cmd, size_i2c_cmd);
if (i2c_write_raw(bus, chip, (uint8_t *)&cmd, size_i2c_cmd) != 0) {
printk(BIOS_ERR, "%s: Cannot complete write to i2c-%d:%#x\n",
__func__, bus, chip);
cec_command->cmd_code = EC_RES_ERROR;
return 1;
}
if (i2c_read_raw(bus, chip, (uint8_t *)&resp, size_i2c_resp) != 0) {
printk(BIOS_ERR, "%s: Cannot complete read from i2c-%d:%#x\n",
__func__, bus, chip);
cec_command->cmd_code = EC_RES_ERROR;
return 1;
}
/* Verify and return response */
cec_command->cmd_code = resp.response;
if (resp.response != EC_RES_SUCCESS) {
printk(BIOS_DEBUG, "%s: Received bad result code %d\n",
__func__, (int)resp.response);
return 1;
}
if (resp.length > cec_command->cmd_size_out) {
printk(BIOS_ERR, "%s: Received len %#02x too large\n",
__func__, (int)resp.length);
cec_command->cmd_code = EC_RES_INVALID_RESPONSE;
return 1;
}
if (!ec_verify_checksum(&resp)) {
cec_command->cmd_code = EC_RES_INVALID_CHECKSUM;
return 1;
}
cec_command->cmd_size_out = resp.length;
memcpy(cec_command->cmd_data_out, resp.data, resp.length);
return 0;
}
#ifndef __PRE_RAM__
u8 google_chromeec_get_event(void)
{
printk(BIOS_ERR, "%s: Not supported.\n", __func__);
return 0;
}
#endif
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