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 #define WILCO_EC_FLAG_RAW_REQUEST BIT(2) /* Do not trim request data */ 18 #define WILCO_EC_FLAG_RAW_RESPONSE BIT(3) /* Do not trim response data */ 19 #define WILCO_EC_FLAG_RAW (WILCO_EC_FLAG_RAW_REQUEST | \ 20 WILCO_EC_FLAG_RAW_RESPONSE) 21 22 /* Normal commands have a maximum 32 bytes of data */ 23 #define EC_MAILBOX_DATA_SIZE 32 24 /* Extended commands have 256 bytes of response data */ 25 #define EC_MAILBOX_DATA_SIZE_EXTENDED 256 26 27 /** 28 * struct wilco_ec_device - Wilco Embedded Controller handle. 29 * @dev: Device handle. 30 * @mailbox_lock: Mutex to ensure one mailbox command at a time. 31 * @io_command: I/O port for mailbox command. Provided by ACPI. 32 * @io_data: I/O port for mailbox data. Provided by ACPI. 33 * @io_packet: I/O port for mailbox packet data. Provided by ACPI. 34 * @data_buffer: Buffer used for EC communication. The same buffer 35 * is used to hold the request and the response. 36 * @data_size: Size of the data buffer used for EC communication. 37 * @debugfs_pdev: The child platform_device used by the debugfs sub-driver. 38 * @rtc_pdev: The child platform_device used by the RTC sub-driver. 39 */ 40 struct wilco_ec_device { 41 struct device *dev; 42 struct mutex mailbox_lock; 43 struct resource *io_command; 44 struct resource *io_data; 45 struct resource *io_packet; 46 void *data_buffer; 47 size_t data_size; 48 struct platform_device *debugfs_pdev; 49 struct platform_device *rtc_pdev; 50 }; 51 52 /** 53 * struct wilco_ec_request - Mailbox request message format. 54 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION 55 * @checksum: Sum of all bytes must be 0. 56 * @mailbox_id: Mailbox identifier, specifies the command set. 57 * @mailbox_version: Mailbox interface version %EC_MAILBOX_VERSION 58 * @reserved: Set to zero. 59 * @data_size: Length of request, data + last 2 bytes of the header. 60 * @command: Mailbox command code, unique for each mailbox_id set. 61 * @reserved_raw: Set to zero for most commands, but is used by 62 * some command types and for raw commands. 63 */ 64 struct wilco_ec_request { 65 u8 struct_version; 66 u8 checksum; 67 u16 mailbox_id; 68 u8 mailbox_version; 69 u8 reserved; 70 u16 data_size; 71 u8 command; 72 u8 reserved_raw; 73 } __packed; 74 75 /** 76 * struct wilco_ec_response - Mailbox response message format. 77 * @struct_version: Should be %EC_MAILBOX_PROTO_VERSION 78 * @checksum: Sum of all bytes must be 0. 79 * @result: Result code from the EC. Non-zero indicates an error. 80 * @data_size: Length of the response data buffer. 81 * @reserved: Set to zero. 82 * @mbox0: EC returned data at offset 0 is unused (always 0) so this byte 83 * is treated as part of the header instead of the data. 84 * @data: Response data buffer. Max size is %EC_MAILBOX_DATA_SIZE_EXTENDED. 85 */ 86 struct wilco_ec_response { 87 u8 struct_version; 88 u8 checksum; 89 u16 result; 90 u16 data_size; 91 u8 reserved[2]; 92 u8 mbox0; 93 u8 data[0]; 94 } __packed; 95 96 /** 97 * enum wilco_ec_msg_type - Message type to select a set of command codes. 98 * @WILCO_EC_MSG_LEGACY: Legacy EC messages for standard EC behavior. 99 * @WILCO_EC_MSG_PROPERTY: Get/Set/Sync EC controlled NVRAM property. 100 * @WILCO_EC_MSG_TELEMETRY_SHORT: 32 bytes of telemetry data provided by the EC. 101 * @WILCO_EC_MSG_TELEMETRY_LONG: 256 bytes of telemetry data provided by the EC. 102 */ 103 enum wilco_ec_msg_type { 104 WILCO_EC_MSG_LEGACY = 0x00f0, 105 WILCO_EC_MSG_PROPERTY = 0x00f2, 106 WILCO_EC_MSG_TELEMETRY_SHORT = 0x00f5, 107 WILCO_EC_MSG_TELEMETRY_LONG = 0x00f6, 108 }; 109 110 /** 111 * struct wilco_ec_message - Request and response message. 112 * @type: Mailbox message type. 113 * @flags: Message flags, e.g. %WILCO_EC_FLAG_NO_RESPONSE. 114 * @command: Mailbox command code. 115 * @result: Result code from the EC. Non-zero indicates an error. 116 * @request_size: Number of bytes to send to the EC. 117 * @request_data: Buffer containing the request data. 118 * @response_size: Number of bytes expected from the EC. 119 * This is 32 by default and 256 if the flag 120 * is set for %WILCO_EC_FLAG_EXTENDED_DATA 121 * @response_data: Buffer containing the response data, should be 122 * response_size bytes and allocated by caller. 123 */ 124 struct wilco_ec_message { 125 enum wilco_ec_msg_type type; 126 u8 flags; 127 u8 command; 128 u8 result; 129 size_t request_size; 130 void *request_data; 131 size_t response_size; 132 void *response_data; 133 }; 134 135 /** 136 * wilco_ec_mailbox() - Send request to the EC and receive the response. 137 * @ec: Wilco EC device. 138 * @msg: Wilco EC message. 139 * 140 * Return: Number of bytes received or negative error code on failure. 141 */ 142 int wilco_ec_mailbox(struct wilco_ec_device *ec, struct wilco_ec_message *msg); 143 144 #endif /* WILCO_EC_H */ 145