145 lines
4.8 KiB
C
145 lines
4.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* ChromeOS Wilco Embedded Controller
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*
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* Copyright 2018 Google LLC
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*/
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#ifndef WILCO_EC_H
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#define WILCO_EC_H
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#include <linux/device.h>
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#include <linux/kernel.h>
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/* Message flags for using the mailbox() interface */
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#define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */
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#define WILCO_EC_FLAG_EXTENDED_DATA BIT(1) /* EC returns 256 data bytes */
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#define WILCO_EC_FLAG_RAW_REQUEST BIT(2) /* Do not trim request data */
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#define WILCO_EC_FLAG_RAW_RESPONSE BIT(3) /* Do not trim response data */
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#define WILCO_EC_FLAG_RAW (WILCO_EC_FLAG_RAW_REQUEST | \
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WILCO_EC_FLAG_RAW_RESPONSE)
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/* Normal commands have a maximum 32 bytes of data */
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#define EC_MAILBOX_DATA_SIZE 32
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/* Extended commands have 256 bytes of response data */
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#define EC_MAILBOX_DATA_SIZE_EXTENDED 256
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/**
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* struct wilco_ec_device - Wilco Embedded Controller handle.
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* @dev: Device handle.
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* @mailbox_lock: Mutex to ensure one mailbox command at a time.
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* @io_command: I/O port for mailbox command. Provided by ACPI.
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* @io_data: I/O port for mailbox data. Provided by ACPI.
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* @io_packet: I/O port for mailbox packet data. Provided by ACPI.
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* @data_buffer: Buffer used for EC communication. The same buffer
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* is used to hold the request and the response.
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* @data_size: Size of the data buffer used for EC communication.
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* @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
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* @rtc_pdev: The child platform_device used by the RTC sub-driver.
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*/
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struct wilco_ec_device {
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struct device *dev;
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struct mutex mailbox_lock;
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struct resource *io_command;
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struct resource *io_data;
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struct resource *io_packet;
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void *data_buffer;
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size_t data_size;
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struct platform_device *debugfs_pdev;
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struct platform_device *rtc_pdev;
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};
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/**
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* struct wilco_ec_request - Mailbox request message format.
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* @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
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* @checksum: Sum of all bytes must be 0.
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* @mailbox_id: Mailbox identifier, specifies the command set.
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* @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
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* @reserved: Set to zero.
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* @data_size: Length of request, data + last 2 bytes of the header.
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* @command: Mailbox command code, unique for each mailbox_id set.
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* @reserved_raw: Set to zero for most commands, but is used by
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* some command types and for raw commands.
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*/
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struct wilco_ec_request {
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u8 struct_version;
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u8 checksum;
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u16 mailbox_id;
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u8 mailbox_version;
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u8 reserved;
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u16 data_size;
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u8 command;
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u8 reserved_raw;
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} __packed;
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/**
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* struct wilco_ec_response - Mailbox response message format.
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* @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
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* @checksum: Sum of all bytes must be 0.
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* @result: Result code from the EC. Non-zero indicates an error.
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* @data_size: Length of the response data buffer.
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* @reserved: Set to zero.
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* @mbox0: EC returned data at offset 0 is unused (always 0) so this byte
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* is treated as part of the header instead of the data.
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* @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
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*/
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struct wilco_ec_response {
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u8 struct_version;
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u8 checksum;
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u16 result;
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u16 data_size;
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u8 reserved[2];
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u8 mbox0;
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u8 data[0];
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} __packed;
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/**
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* enum wilco_ec_msg_type - Message type to select a set of command codes.
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* @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
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* @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
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* @WILCO_EC_MSG_TELEMETRY_SHORT: 32 bytes of telemetry data provided by the EC.
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* @WILCO_EC_MSG_TELEMETRY_LONG: 256 bytes of telemetry data provided by the EC.
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*/
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enum wilco_ec_msg_type {
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WILCO_EC_MSG_LEGACY = 0x00f0,
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WILCO_EC_MSG_PROPERTY = 0x00f2,
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WILCO_EC_MSG_TELEMETRY_SHORT = 0x00f5,
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WILCO_EC_MSG_TELEMETRY_LONG = 0x00f6,
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};
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/**
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* struct wilco_ec_message - Request and response message.
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* @type: Mailbox message type.
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* @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
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* @command: Mailbox command code.
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* @result: Result code from the EC. Non-zero indicates an error.
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* @request_size: Number of bytes to send to the EC.
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* @request_data: Buffer containing the request data.
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* @response_size: Number of bytes expected from the EC.
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* This is 32 by default and 256 if the flag
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* is set for %WILCO_EC_FLAG_EXTENDED_DATA
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* @response_data: Buffer containing the response data, should be
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* response_size bytes and allocated by caller.
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*/
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struct wilco_ec_message {
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enum wilco_ec_msg_type type;
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u8 flags;
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u8 command;
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u8 result;
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size_t request_size;
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void *request_data;
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size_t response_size;
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void *response_data;
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};
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/**
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* wilco_ec_mailbox() - Send request to the EC and receive the response.
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* @ec: Wilco EC device.
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* @msg: Wilco EC message.
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*
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* Return: Number of bytes received or negative error code on failure.
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*/
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int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
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#endif /* WILCO_EC_H */
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