bootutil: Enable hash calculation directly on storage

The commit add support for passing storage device address space
to hash calculation functions, which allows to use hardware
accelerated hash calculation on storage.
This feature only works when image encryption is not enabled
and all slots are defined within internal storage of device.

The feature is enabled with MCUboot configuration option
MCUBOOT_HASH_STORAGE_DIRECTLY.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>

boot/bootutil/src/image_validate.c

@@ -68,13 +68,15 @@ bootutil_img_hash(struct enc_key_data *enc_state, int image_index,
                   uint8_t *seed, int seed_len)
 {
     bootutil_sha_context sha_ctx;
-    uint32_t blk_sz;
     uint32_t size;
     uint16_t hdr_size;
-    uint32_t off;
-    int rc;
     uint32_t blk_off;
     uint32_t tlv_off;
+#if !defined(MCUBOOT_HASH_STORAGE_DIRECTLY)
+    int rc;
+    uint32_t off;
+    uint32_t blk_sz;
+#endif
 
 #if (BOOT_IMAGE_NUMBER == 1) || !defined(MCUBOOT_ENC_IMAGES) || \
     defined(MCUBOOT_RAM_LOAD)
@@ -117,6 +119,12 @@ bootutil_img_hash(struct enc_key_data *enc_state, int image_index,
     /* If protected TLVs are present they are also hashed. */
     size += hdr->ih_protect_tlv_size;
 
+#ifdef MCUBOOT_HASH_STORAGE_DIRECTLY
+    /* No chunk loading, storage is mapped to address space and can
+     * be directly given to hashing function.
+     */
+    bootutil_sha_update(&sha_ctx, (void *)flash_area_get_off(fap), size);
+#else /* MCUBOOT_HASH_STORAGE_DIRECTLY */
 #ifdef MCUBOOT_RAM_LOAD
     bootutil_sha_update(&sha_ctx,
                         (void*)(IMAGE_RAM_BASE + hdr->ih_load_addr),
@@ -161,6 +169,7 @@ bootutil_img_hash(struct enc_key_data *enc_state, int image_index,
         bootutil_sha_update(&sha_ctx, tmp_buf, blk_sz);
     }
 #endif /* MCUBOOT_RAM_LOAD */
+#endif /* MCUBOOT_HASH_STORAGE_DIRECTLY */
     bootutil_sha_finish(&sha_ctx, hash_result);
     bootutil_sha_drop(&sha_ctx);