feat(handoff): add basic firmware handoff tests

Add tests to sanity check information shared between BL31 and NS world
using the firmware handoff framework.

Change-Id: I9d00292db7732157d0815e6159438c0db08551ad
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/include/lib/transfer_list.h b/include/lib/transfer_list.h
new file mode 100644
index 0000000..9ee1f55
--- /dev/null
+++ b/include/lib/transfer_list.h
@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2023, Linaro Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef __TRANSFER_LIST_H
+#define __TRANSFER_LIST_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include <lib/utils_def.h>
+
+#define TRANSFER_LIST_SIGNATURE U(0x006ed0ff)
+#define TRANSFER_LIST_VERSION U(0x0001)
+
+// Init value of maximum alignment required by any TE data in the TL
+// specified as a power of two
+#define TRANSFER_LIST_INIT_MAX_ALIGN U(3)
+
+// alignment required by TE header start address, in bytes
+#define TRANSFER_LIST_GRANULE U(8)
+
+// version of the register convention used.
+// Set to 1 for both AArch64 and AArch32 according to fw handoff spec v0.9
+#define REGISTER_CONVENTION_VERSION_MASK (1 << 24)
+
+#ifndef __ASSEMBLER__
+
+enum transfer_list_tag_id {
+	TL_TAG_EMPTY = 0,
+	TL_TAG_FDT = 1,
+	TL_TAG_HOB_BLOCK = 2,
+	TL_TAG_HOB_LIST = 3,
+	TL_TAG_ACPI_TABLE_AGGREGATE = 4,
+};
+
+enum transfer_list_ops {
+	TL_OPS_NON, // invalid for any operation
+	TL_OPS_ALL, // valid for all operations
+};
+
+struct transfer_list_header {
+	uint32_t signature;
+	uint8_t checksum;
+	uint8_t version;
+	uint8_t hdr_size;
+	uint8_t alignment; // max alignment of TE data
+	uint32_t size; // TL header + all TEs
+	uint32_t max_size;
+	/*
+	 * Commented out element used to visualize dynamic part of the
+	 * data structure.
+	 *
+	 * Note that struct transfer_list_entry also is dynamic in size
+	 * so the elements can't be indexed directly but instead must be
+	 * traversed in order
+	 *
+	 * struct transfer_list_entry entries[];
+	 */
+};
+
+struct transfer_list_entry {
+	uint16_t tag_id;
+	uint8_t reserved0; // place holder
+	uint8_t hdr_size;
+	uint32_t data_size;
+	/*
+	 * Commented out element used to visualize dynamic part of the
+	 * data structure.
+	 *
+	 * Note that padding is added at the end of @data to make to reach
+	 * a 8-byte boundary.
+	 *
+	 * uint8_t	data[ROUNDUP(data_size, 8)];
+	 */
+};
+
+bool transfer_list_verify_checksum(const struct transfer_list_header *tl);
+
+void *transfer_list_entry_data(struct transfer_list_entry *entry);
+
+struct transfer_list_entry *transfer_list_find(struct transfer_list_header *tl,
+					       uint16_t tag_id);
+
+enum transfer_list_ops
+transfer_list_check_header(const struct transfer_list_header *tl);
+
+#endif /*__ASSEMBLER__*/
+#endif /*__TRANSFER_LIST_H*/