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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * ChromeOS Wilco Embedded Controller
4 *
5 * Copyright 2018 Google LLC
6 */
7
8#ifndef WILCO_EC_H
9#define WILCO_EC_H
10
11#include <linux/device.h>
12#include <linux/kernel.h>
13
14/* Message flags for using the mailbox() interface */
15#define WILCO_EC_FLAG_NO_RESPONSE BIT(0) /* EC does not respond */
16#define WILCO_EC_FLAG_EXTENDED_DATA BIT(1) /* EC returns 256 data bytes */
17
18/* Normal commands have a maximum 32 bytes of data */
19#define EC_MAILBOX_DATA_SIZE 32
20/* Extended commands have 256 bytes of response data */
21#define EC_MAILBOX_DATA_SIZE_EXTENDED 256
22
23/**
24 * struct wilco_ec_device - Wilco Embedded Controller handle.
25 * @dev: Device handle.
26 * @mailbox_lock: Mutex to ensure one mailbox command at a time.
27 * @io_command: I/O port for mailbox command. Provided by ACPI.
28 * @io_data: I/O port for mailbox data. Provided by ACPI.
29 * @io_packet: I/O port for mailbox packet data. Provided by ACPI.
30 * @data_buffer: Buffer used for EC communication. The same buffer
31 * is used to hold the request and the response.
32 * @data_size: Size of the data buffer used for EC communication.
33 * @debugfs_pdev: The child platform_device used by the debugfs sub-driver.
34 * @rtc_pdev: The child platform_device used by the RTC sub-driver.
35 */
36struct wilco_ec_device {
37 struct device *dev;
38 struct mutex mailbox_lock;
39 struct resource *io_command;
40 struct resource *io_data;
41 struct resource *io_packet;
42 void *data_buffer;
43 size_t data_size;
44 struct platform_device *debugfs_pdev;
45 struct platform_device *rtc_pdev;
46};
47
48/**
49 * struct wilco_ec_request - Mailbox request message format.
50 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
51 * @checksum: Sum of all bytes must be 0.
52 * @mailbox_id: Mailbox identifier, specifies the command set.
53 * @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION
54 * @reserved: Set to zero.
55 * @data_size: Length of following data.
56 */
57struct wilco_ec_request {
58 u8 struct_version;
59 u8 checksum;
60 u16 mailbox_id;
61 u8 mailbox_version;
62 u8 reserved;
63 u16 data_size;
64} __packed;
65
66/**
67 * struct wilco_ec_response - Mailbox response message format.
68 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION
69 * @checksum: Sum of all bytes must be 0.
70 * @result: Result code from the EC. Non-zero indicates an error.
71 * @data_size: Length of the response data buffer.
72 * @reserved: Set to zero.
73 * @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED.
74 */
75struct wilco_ec_response {
76 u8 struct_version;
77 u8 checksum;
78 u16 result;
79 u16 data_size;
80 u8 reserved[2];
81 u8 data[0];
82} __packed;
83
84/**
85 * enum wilco_ec_msg_type - Message type to select a set of command codes.
86 * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior.
87 * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property.
88 * @WILCO_EC_MSG_TELEMETRY_SHORT: 32 bytes of telemetry data provided by the EC.
89 * @WILCO_EC_MSG_TELEMETRY_LONG: 256 bytes of telemetry data provided by the EC.
90 */
91enum wilco_ec_msg_type {
92 WILCO_EC_MSG_LEGACY = 0x00f0,
93 WILCO_EC_MSG_PROPERTY = 0x00f2,
94 WILCO_EC_MSG_TELEMETRY_SHORT = 0x00f5,
95 WILCO_EC_MSG_TELEMETRY_LONG = 0x00f6,
96};
97
98/**
99 * struct wilco_ec_message - Request and response message.
100 * @type: Mailbox message type.
101 * @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE.
102 * @request_size: Number of bytes to send to the EC.
103 * @request_data: Buffer containing the request data.
104 * @response_size: Number of bytes to read from EC.
105 * @response_data: Buffer containing the response data, should be
106 * response_size bytes and allocated by caller.
107 */
108struct wilco_ec_message {
109 enum wilco_ec_msg_type type;
110 u8 flags;
111 size_t request_size;
112 void *request_data;
113 size_t response_size;
114 void *response_data;
115};
116
117/**
118 * wilco_ec_mailbox() - Send request to the EC and receive the response.
119 * @ec: Wilco EC device.
120 * @msg: Wilco EC message.
121 *
122 * Return: Number of bytes received or negative error code on failure.
123 */
124int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg);
125
126#endif /* WILCO_EC_H */