mirror of https://gitee.com/openkylin/linux.git
116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
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/*
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* ChromeOS EC communication protocol helper functions
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*
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* Copyright (C) 2015 Google, Inc
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/mfd/cros_ec.h>
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#include <linux/delay.h>
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#include <linux/device.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#define EC_COMMAND_RETRIES 50
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int cros_ec_prepare_tx(struct cros_ec_device *ec_dev,
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struct cros_ec_command *msg)
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{
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uint8_t *out;
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int csum, i;
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BUG_ON(msg->outsize > EC_PROTO2_MAX_PARAM_SIZE);
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out = ec_dev->dout;
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out[0] = EC_CMD_VERSION0 + msg->version;
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out[1] = msg->command;
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out[2] = msg->outsize;
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csum = out[0] + out[1] + out[2];
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for (i = 0; i < msg->outsize; i++)
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csum += out[EC_MSG_TX_HEADER_BYTES + i] = msg->data[i];
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out[EC_MSG_TX_HEADER_BYTES + msg->outsize] = (uint8_t)(csum & 0xff);
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return EC_MSG_TX_PROTO_BYTES + msg->outsize;
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}
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EXPORT_SYMBOL(cros_ec_prepare_tx);
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int cros_ec_check_result(struct cros_ec_device *ec_dev,
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struct cros_ec_command *msg)
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{
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switch (msg->result) {
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case EC_RES_SUCCESS:
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return 0;
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case EC_RES_IN_PROGRESS:
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dev_dbg(ec_dev->dev, "command 0x%02x in progress\n",
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msg->command);
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return -EAGAIN;
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default:
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dev_dbg(ec_dev->dev, "command 0x%02x returned %d\n",
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msg->command, msg->result);
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return 0;
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}
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}
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EXPORT_SYMBOL(cros_ec_check_result);
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int cros_ec_cmd_xfer(struct cros_ec_device *ec_dev,
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struct cros_ec_command *msg)
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{
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int ret;
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mutex_lock(&ec_dev->lock);
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ret = ec_dev->cmd_xfer(ec_dev, msg);
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if (msg->result == EC_RES_IN_PROGRESS) {
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int i;
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struct cros_ec_command *status_msg;
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struct ec_response_get_comms_status *status;
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status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
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GFP_KERNEL);
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if (!status_msg) {
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ret = -ENOMEM;
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goto exit;
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}
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status_msg->version = 0;
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status_msg->command = EC_CMD_GET_COMMS_STATUS;
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status_msg->insize = sizeof(*status);
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status_msg->outsize = 0;
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/*
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* Query the EC's status until it's no longer busy or
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* we encounter an error.
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*/
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for (i = 0; i < EC_COMMAND_RETRIES; i++) {
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usleep_range(10000, 11000);
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ret = ec_dev->cmd_xfer(ec_dev, status_msg);
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if (ret < 0)
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break;
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msg->result = status_msg->result;
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if (status_msg->result != EC_RES_SUCCESS)
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break;
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status = (struct ec_response_get_comms_status *)
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status_msg->data;
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if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
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break;
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}
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kfree(status_msg);
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}
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exit:
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mutex_unlock(&ec_dev->lock);
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return ret;
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}
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EXPORT_SYMBOL(cros_ec_cmd_xfer);
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