core: REE FS: use a single file per object

Prior to this commit each persistent object was represented by a
directory with several files. With this commit each persistent object is
represented by a single file instead to simplify the implementation.

Reviewed-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Etienne Carriere <etienne.carriere@linaro.org>
Tested-by: Jens Wiklander <jens.wiklander@linaro.org> (QEMU)
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

core/include/tee/tee_fs_key_manager.h

@@ -41,11 +41,29 @@
 #define TEE_FS_KM_IV_LEN            12  /* bytes */
 #define TEE_FS_KM_MAX_TAG_LEN       16  /* bytes */
 
+
+#define BLOCK_FILE_SHIFT	12
+
+#define BLOCK_FILE_SIZE		(1 << BLOCK_FILE_SHIFT)
+
+#define NUM_BLOCKS_PER_FILE	1024
+
 enum tee_fs_file_type {
 	META_FILE,
 	BLOCK_FILE
 };
 
+struct tee_fs_file_info {
+	size_t length;
+	uint32_t backup_version_table[NUM_BLOCKS_PER_FILE / 32];
+};
+
+struct tee_fs_file_meta {
+	struct tee_fs_file_info info;
+	uint8_t encrypted_fek[TEE_FS_KM_FEK_SIZE];
+	uint32_t counter;
+};
+
 struct common_header {
 	uint8_t iv[TEE_FS_KM_IV_LEN];
 	uint8_t tag[TEE_FS_KM_MAX_TAG_LEN];