+/**
+ * DOC: GuC Firmware Layout
+ *
+ * The GuC firmware layout looks like this:
+ *
+ * +-------------------------------+
+ * | guc_css_header |
+ * | contains major/minor version |
+ * +-------------------------------+
+ * | uCode |
+ * +-------------------------------+
+ * | RSA signature |
+ * +-------------------------------+
+ * | modulus key |
+ * +-------------------------------+
+ * | exponent val |
+ * +-------------------------------+
+ *
+ * The firmware may or may not have modulus key and exponent data. The header,
+ * uCode and RSA signature are must-have components that will be used by driver.
+ * Length of each components, which is all in dwords, can be found in header.
+ * In the case that modulus and exponent are not present in fw, a.k.a truncated
+ * image, the length value still appears in header.
+ *
+ * Driver will do some basic fw size validation based on the following rules:
+ *
+ * 1. Header, uCode and RSA are must-have components.
+ * 2. All firmware components, if they present, are in the sequence illustrated
+ * in the layout table above.
+ * 3. Length info of each component can be found in header, in dwords.
+ * 4. Modulus and exponent key are not required by driver. They may not appear
+ * in fw. So driver will load a truncated firmware in this case.
+ */
+
+struct guc_css_header {
+ uint32_t module_type;
+ /* header_size includes all non-uCode bits, including css_header, rsa
+ * key, modulus key and exponent data. */
+ uint32_t header_size_dw;
+ uint32_t header_version;
+ uint32_t module_id;
+ uint32_t module_vendor;
+ union {
+ struct {
+ uint8_t day;
+ uint8_t month;
+ uint16_t year;
+ };
+ uint32_t date;
+ };
+ uint32_t size_dw; /* uCode plus header_size_dw */
+ uint32_t key_size_dw;
+ uint32_t modulus_size_dw;
+ uint32_t exponent_size_dw;
+ union {
+ struct {
+ uint8_t hour;
+ uint8_t min;
+ uint16_t sec;
+ };
+ uint32_t time;
+ };
+
+ char username[8];
+ char buildnumber[12];
+ uint32_t device_id;
+ uint32_t guc_sw_version;
+ uint32_t prod_preprod_fw;
+ uint32_t reserved[12];
+ uint32_t header_info;
+} __packed;
+