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/*
* ChromeOS EC communication protocol helper functions
*
* Copyright (C) 2015 Google, Inc
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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 <linux/mfd/cros_ec.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#define EC_COMMAND_RETRIES 50
int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg)
{
uint8_t *out;
int csum, i;
BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
out = ec_dev->dout;
out[0] = EC_CMD_VERSION0 + msg->version;
out[1] = msg->command;
out[2] = msg->outsize;
csum = out[0] + out[1] + out[2];
for (i = 0; i < msg->outsize; i++)
csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
return EC_MSG_TX_PROTO_BYTES + msg->outsize;
}
EXPORT_SYMBOL(cros_ec_prepare_tx);
int cros_ec_check_result(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg)
{
switch (msg->result) {
case EC_RES_SUCCESS:
return 0;
case EC_RES_IN_PROGRESS:
dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
msg->command);
return -EAGAIN;
default:
dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
msg->command, msg->result);
return 0;
}
}
EXPORT_SYMBOL(cros_ec_check_result);
int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
struct cros_ec_command *msg)
{
int ret;
mutex_lock(&ec_dev->lock);
ret = ec_dev->cmd_xfer(ec_dev, msg);
if (msg->result == EC_RES_IN_PROGRESS) {
int i;
struct cros_ec_command *status_msg;
struct ec_response_get_comms_status *status;
status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
GFP_KERNEL);
if (!status_msg) {
ret = -ENOMEM;
goto exit;
}
status_msg->version = 0;
status_msg->command = EC_CMD_GET_COMMS_STATUS;
status_msg->insize = sizeof(*status);
status_msg->outsize = 0;
/*
* Query the EC's status until it's no longer busy or
* we encounter an error.
*/
for (i = 0; i < EC_COMMAND_RETRIES; i++) {
usleep_range(10000, 11000);
ret = ec_dev->cmd_xfer(ec_dev, status_msg);
if (ret < 0)
break;
msg->result = status_msg->result;
if (status_msg->result != EC_RES_SUCCESS)
break;
status = (struct ec_response_get_comms_status *)
status_msg->data;
if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
break;
}
kfree(status_msg);
}
exit:
mutex_unlock(&ec_dev->lock);
return ret;
}
EXPORT_SYMBOL(cros_ec_cmd_xfer);
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