+/*****************************************************************************/
+
+/*
+ * Protocol version 2 for I2C and SPI send a request this way:
+ *
+ * 0 EC_CMD_VERSION0 + (command version)
+ * 1 Command number
+ * 2 Length of params = N
+ * 3..N+2 Params, if any
+ * N+3 8-bit checksum of bytes 0..N+2
+ *
+ * The corresponding response is:
+ *
+ * 0 Result code (EC_RES_*)
+ * 1 Length of params = M
+ * 2..M+1 Params, if any
+ * M+2 8-bit checksum of bytes 0..M+1
+ */
+#define EC_PROTO2_REQUEST_HEADER_BYTES 3
+#define EC_PROTO2_REQUEST_TRAILER_BYTES 1
+#define EC_PROTO2_REQUEST_OVERHEAD (EC_PROTO2_REQUEST_HEADER_BYTES + \
+ EC_PROTO2_REQUEST_TRAILER_BYTES)
+
+#define EC_PROTO2_RESPONSE_HEADER_BYTES 2
+#define EC_PROTO2_RESPONSE_TRAILER_BYTES 1
+#define EC_PROTO2_RESPONSE_OVERHEAD (EC_PROTO2_RESPONSE_HEADER_BYTES + \
+ EC_PROTO2_RESPONSE_TRAILER_BYTES)
+
+/* Parameter length was limited by the LPC interface */
+#define EC_PROTO2_MAX_PARAM_SIZE 0xfc
+
+/* Maximum request and response packet sizes for protocol version 2 */
+#define EC_PROTO2_MAX_REQUEST_SIZE (EC_PROTO2_REQUEST_OVERHEAD + \
+ EC_PROTO2_MAX_PARAM_SIZE)
+#define EC_PROTO2_MAX_RESPONSE_SIZE (EC_PROTO2_RESPONSE_OVERHEAD + \
+ EC_PROTO2_MAX_PARAM_SIZE)
+
+/*****************************************************************************/
+
+/*
+ * Value written to legacy command port / prefix byte to indicate protocol
+ * 3+ structs are being used. Usage is bus-dependent.
+ */
+#define EC_COMMAND_PROTOCOL_3 0xda
+
+#define EC_HOST_REQUEST_VERSION 3
+
+/* Version 3 request from host */
+struct ec_host_request {
+ /* Struct version (=3)
+ *
+ * EC will return EC_RES_INVALID_HEADER if it receives a header with a
+ * version it doesn't know how to parse.
+ */
+ uint8_t struct_version;
+
+ /*
+ * Checksum of request and data; sum of all bytes including checksum
+ * should total to 0.
+ */
+ uint8_t checksum;
+
+ /* Command code */
+ uint16_t command;
+
+ /* Command version */
+ uint8_t command_version;
+
+ /* Unused byte in current protocol version; set to 0 */
+ uint8_t reserved;
+
+ /* Length of data which follows this header */
+ uint16_t data_len;
+} __packed;
+
+#define EC_HOST_RESPONSE_VERSION 3
+
+/* Version 3 response from EC */
+struct ec_host_response {
+ /* Struct version (=3) */
+ uint8_t struct_version;
+
+ /*
+ * Checksum of response and data; sum of all bytes including checksum
+ * should total to 0.
+ */
+ uint8_t checksum;
+
+ /* Result code (EC_RES_*) */
+ uint16_t result;
+
+ /* Length of data which follows this header */
+ uint16_t data_len;
+
+ /* Unused bytes in current protocol version; set to 0 */
+ uint16_t reserved;
+} __packed;
+
+/*****************************************************************************/