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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.
*/
#include <console/console.h>
#include <delay.h>
#include "ec.h"
#include "ec_commands.h"
#include <spi-generic.h>
#include <timer.h>
/* This is assuming that this driver is not used on x86. If that changes, this
might need to become a CAR_GLOBAL or maybe even more complicated. */
static struct stopwatch cs_cooldown_sw;
static const long cs_cooldown_us = 200;
static const uint8_t EcFramingByte = 0xec;
#define PROTO3_MAX_PACKET_SIZE 268
static uint8_t req_buf[PROTO3_MAX_PACKET_SIZE];
static uint8_t resp_buf[PROTO3_MAX_PACKET_SIZE];
void *crosec_get_buffer(size_t size, int req)
{
if (size > PROTO3_MAX_PACKET_SIZE) {
printk(BIOS_DEBUG, "Proto v3 buffer request too large: %zu!\n",
size);
return NULL;
}
if (req)
return req_buf;
else
return resp_buf;
}
static int crosec_spi_io(size_t req_size, size_t resp_size, void *context)
{
struct spi_slave *slave = (struct spi_slave *)context;
int ret = 0;
while (!stopwatch_expired(&cs_cooldown_sw))
/* Wait minimum delay between CS assertions. */;
spi_claim_bus(slave);
/* Allow EC to ramp up clock after being awaken.
* See chrome-os-partner:32223 for more details. */
udelay(CONFIG_EC_GOOGLE_CHROMEEC_SPI_WAKEUP_DELAY_US);
if (spi_xfer(slave, req_buf, req_size, NULL, 0)) {
printk(BIOS_ERR, "%s: Failed to send request.\n", __func__);
ret = -1;
goto out;
}
uint8_t byte;
struct stopwatch sw;
// Wait 1s for a framing byte.
stopwatch_init_usecs_expire(&sw, USECS_PER_SEC);
while (1) {
if (spi_xfer(slave, NULL, 0, &byte, sizeof(byte))) {
printk(BIOS_ERR, "%s: Failed to receive byte.\n",
__func__);
ret = -1;
goto out;
}
if (byte == EcFramingByte)
break;
if (stopwatch_expired(&sw)) {
printk(BIOS_ERR,
"%s: Timeout waiting for framing byte.\n",
__func__);
ret = -1;
goto out;
}
}
if (spi_xfer(slave, NULL, 0, resp_buf, resp_size)) {
printk(BIOS_ERR, "%s: Failed to receive response.\n", __func__);
ret = -1;
}
out:
spi_release_bus(slave);
stopwatch_init_usecs_expire(&cs_cooldown_sw, cs_cooldown_us);
return ret;
}
int google_chromeec_command(struct chromeec_command *cec_command)
{
static int done = 0;
static struct spi_slave slave;
if (!done) {
if (spi_setup_slave(CONFIG_EC_GOOGLE_CHROMEEC_SPI_BUS,
CONFIG_EC_GOOGLE_CHROMEEC_SPI_CHIP, &slave))
return -1;
stopwatch_init(&cs_cooldown_sw);
done = 1;
}
return crosec_command_proto(cec_command, crosec_spi_io, &slave);
}
#ifndef __PRE_RAM__
u8 google_chromeec_get_event(void)
{
printk(BIOS_ERR, "%s: Not supported.\n", __func__);
return 0;
}
#endif
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