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/* SPDX-License-Identifier: GPL-2.0 */
/*
* ChromeOS Wilco Embedded Controller
*
* Copyright 2018 Google LLC
*/
#ifndef WILCO_EC_H
#define WILCO_EC_H
#include <linux/device.h>
#include <linux/kernel.h>
/* Message flags for using the mailbox() interface */
#define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */
/* Normal commands have a maximum 32 bytes of data */
#define EC_MAILBOX_DATA_SIZE 32
/**
* struct wilco_ec_device - Wilco Embedded Controller handle.
* @dev: Device handle.
* @mailbox_lock: Mutex to ensure one mailbox command at a time.
* @io_command: I/O port for mailbox command. Provided by ACPI.
* @io_data: I/O port for mailbox data. Provided by ACPI.
* @io_packet: I/O port for mailbox packet data. Provided by ACPI.
* @data_buffer: Buffer used for EC communication. The same buffer
* is used to hold the request and the response.
* @data_size: Size of the data buffer used for EC communication.
* @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
* @rtc_pdev: The child platform_device used by the RTC sub-driver.
* @telem_pdev: The child platform_device used by the telemetry sub-driver.
*/
struct wilco_ec_device {
struct device *dev;
struct mutex mailbox_lock;
struct resource *io_command;
struct resource *io_data;
struct resource *io_packet;
void *data_buffer;
size_t data_size;
struct platform_device *debugfs_pdev;
struct platform_device *rtc_pdev;
struct platform_device *telem_pdev;
};
/**
* struct wilco_ec_request - Mailbox request message format.
* @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
* @checksum: Sum of all bytes must be 0.
* @mailbox_id: Mailbox identifier, specifies the command set.
* @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
* @reserved: Set to zero.
* @data_size: Length of following data.
*/
struct wilco_ec_request {
u8 struct_version;
u8 checksum;
u16 mailbox_id;
u8 mailbox_version;
u8 reserved;
u16 data_size;
} __packed;
/**
* struct wilco_ec_response - Mailbox response message format.
* @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
* @checksum: Sum of all bytes must be 0.
* @result: Result code from the EC. Non-zero indicates an error.
* @data_size: Length of the response data buffer.
* @reserved: Set to zero.
* @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
*/
struct wilco_ec_response {
u8 struct_version;
u8 checksum;
u16 result;
u16 data_size;
u8 reserved[2];
u8 data[0];
} __packed;
/**
* enum wilco_ec_msg_type - Message type to select a set of command codes.
* @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
* @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
* @WILCO_EC_MSG_TELEMETRY: Request telemetry data from the EC.
*/
enum wilco_ec_msg_type {
WILCO_EC_MSG_LEGACY = 0x00f0,
WILCO_EC_MSG_PROPERTY = 0x00f2,
WILCO_EC_MSG_TELEMETRY = 0x00f5,
};
/**
* struct wilco_ec_message - Request and response message.
* @type: Mailbox message type.
* @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
* @request_size: Number of bytes to send to the EC.
* @request_data: Buffer containing the request data.
* @response_size: Number of bytes to read from EC.
* @response_data: Buffer containing the response data, should be
* response_size bytes and allocated by caller.
*/
struct wilco_ec_message {
enum wilco_ec_msg_type type;
u8 flags;
size_t request_size;
void *request_data;
size_t response_size;
void *response_data;
};
/**
* wilco_ec_mailbox() - Send request to the EC and receive the response.
* @ec: Wilco EC device.
* @msg: Wilco EC message.
*
* Return: Number of bytes received or negative error code on failure.
*/
int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
/*
* A Property is typically a data item that is stored to NVRAM
* by the EC. Each of these data items has an index associated
* with it, known as the Property ID (PID). Properties may have
* variable lengths, up to a max of WILCO_EC_PROPERTY_MAX_SIZE
* bytes. Properties can be simple integers, or they may be more
* complex binary data.
*/
#define WILCO_EC_PROPERTY_MAX_SIZE 4
/**
* struct ec_property_set_msg - Message to get or set a property.
* @property_id: Which property to get or set.
* @length: Number of bytes of |data| that are used.
* @data: Actual property data.
*/
struct wilco_ec_property_msg {
u32 property_id;
int length;
u8 data[WILCO_EC_PROPERTY_MAX_SIZE];
};
/**
* wilco_ec_get_property() - Retrieve a property from the EC.
* @ec: Embedded Controller device.
* @prop_msg: Message for request and response.
*
* The property_id field of |prop_msg| should be filled before calling this
* function. The result will be stored in the data and length fields.
*
* Return: 0 on success, negative error code on failure.
*/
int wilco_ec_get_property(struct wilco_ec_device *ec,
struct wilco_ec_property_msg *prop_msg);
/**
* wilco_ec_set_property() - Store a property on the EC.
* @ec: Embedded Controller device.
* @prop_msg: Message for request and response.
*
* The property_id, length, and data fields of |prop_msg| should be
* filled before calling this function.
*
* Return: 0 on success, negative error code on failure.
*/
int wilco_ec_set_property(struct wilco_ec_device *ec,
struct wilco_ec_property_msg *prop_msg);
/**
* wilco_ec_get_byte_property() - Retrieve a byte-size property from the EC.
* @ec: Embedded Controller device.
* @property_id: Which property to retrieve.
* @val: The result value, will be filled by this function.
*
* Return: 0 on success, negative error code on failure.
*/
int wilco_ec_get_byte_property(struct wilco_ec_device *ec, u32 property_id,
u8 *val);
/**
* wilco_ec_get_byte_property() - Store a byte-size property on the EC.
* @ec: Embedded Controller device.
* @property_id: Which property to store.
* @val: Value to store.
*
* Return: 0 on success, negative error code on failure.
*/
int wilco_ec_set_byte_property(struct wilco_ec_device *ec, u32 property_id,
u8 val);
/**
* wilco_ec_add_sysfs() - Create sysfs entries
* @ec: Wilco EC device
*
* wilco_ec_remove_sysfs() needs to be called afterwards
* to perform the necessary cleanup.
*
* Return: 0 on success or negative error code on failure.
*/
int wilco_ec_add_sysfs(struct wilco_ec_device *ec);
void wilco_ec_remove_sysfs(struct wilco_ec_device *ec);
#endif /* WILCO_EC_H */
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