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 */ 36 struct 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 */ 57 struct 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 */ 75 struct 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 */ 91 enum 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 */ 108 struct 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 */ 124 int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg); 125 126 #endif /* WILCO_EC_H */ 127