| /* |
| * 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); |