boot/bootutil: Make RAM loading methods public

RAM loading methods are currently private, which prevents external
modules with hooks from using them. This patch makes them public.

An interesting note is that a new method,
`boot_load_image_from_flash_to_sram()`, is added so that code can
actually set the image to be loaded - currently, that is inferred from
current boot loader state, but external code can't directly access
members of relevant `struct boot_loader_state`.

Signed-off-by: Ederson de Souza <[email protected]>

Author: edersondisouza

boot/bootutil/include/bootutil/bootutil_public.h

@@ -311,6 +311,41 @@ int
 boot_image_load_header(const struct flash_area *fa_p,
                        struct image_header *hdr);
 
+#ifdef MCUBOOT_RAM_LOAD
+/**
+ * Loads image with given header to RAM.
+ *
+ * Destination on RAM and size is described on image header.
+ *
+ * @param[in]   state   boot loader state
+ * @param[in]   hdr     image header
+ *
+ * @return              0 on success, error code otherwise
+ */
+int boot_load_image_from_flash_to_sram(struct boot_loader_state *state,
+                                       struct image_header *hdr);
+
+/**
+ * Removes an image from SRAM, by overwriting it with zeros.
+ *
+ * @param  state        Boot loader status information.
+ *
+ * @return              0 on success; nonzero on failure.
+ */
+int boot_remove_image_from_sram(struct boot_loader_state *state);
+
+/**
+ * Removes an image from flash by erasing the corresponding flash area
+ *
+ * @param  state    Boot loader status information.
+ * @param  slot     The flash slot of the image to be erased.
+ *
+ * @return          0 on success; nonzero on failure.
+ */
+int boot_remove_image_from_flash(struct boot_loader_state *state,
+                                 uint32_t slot);
+#endif
+
 #ifdef __cplusplus
 }
 #endif

boot/bootutil/src/bootutil_priv.h

@@ -503,9 +503,6 @@ struct bootsim_ram_info *bootsim_get_ram_info(void);
     (size)), 0)
 
 int boot_load_image_to_sram(struct boot_loader_state *state);
-int boot_remove_image_from_sram(struct boot_loader_state *state);
-int boot_remove_image_from_flash(struct boot_loader_state *state,
-                                 uint32_t slot);
 #else
 #define IMAGE_RAM_BASE ((uintptr_t)0)
 

boot/bootutil/src/ram_load.c

@@ -438,3 +438,17 @@ boot_remove_image_from_flash(struct boot_loader_state *state, uint32_t slot)
 
     return rc;
 }
+
+int boot_load_image_from_flash_to_sram(struct boot_loader_state *state,
+                                       struct image_header *hdr)
+{
+    int active_slot;
+
+    /* boot_load_image_to_sram will load the image from state active_slot,
+     * so force it before loading the image.
+     */
+    active_slot = state->slot_usage[BOOT_CURR_IMG(state)].active_slot;
+    BOOT_IMG(state, active_slot).hdr = *hdr;
+
+    return boot_load_image_to_sram(state);
+}