bootutil_public: made boot_read_swap_state_by_id() API

Made boot_read_swap_state_by_id() public API
function.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>

Author: nvlsianpu

boot/bootutil/include/bootutil/bootutil_public.h

@@ -88,6 +88,14 @@ extern "C" {
 
 #define BOOT_MAGIC_SZ (sizeof boot_img_magic)
 
+struct boot_swap_state {
+    uint8_t magic;      /* One of the BOOT_MAGIC_[...] values. */
+    uint8_t swap_type;  /* One of the BOOT_SWAP_TYPE_[...] values. */
+    uint8_t copy_done;  /* One of the BOOT_FLAG_[...] values. */
+    uint8_t image_ok;   /* One of the BOOT_FLAG_[...] values. */
+    uint8_t image_num;  /* Boot status belongs to this image */
+};
+
 /**
  * @brief Determines the action, if any, that mcuboot will take on a image pair.
  *
@@ -153,6 +161,17 @@ uint32_t boot_swap_info_off(const struct flash_area *fap);
  */
 int boot_read_image_ok(const struct flash_area *fap, uint8_t *image_ok);
 
+/**
+ * @brief Read the image swap state
+ *
+ * @param flash_area_id Id of flash parttition from which trailer will be read.
+ * @param state Struture for holding swap state.
+ *
+ * @return 0 on success, nonzero errno code on fail.
+ */
+int
+boot_read_swap_state_by_id(int flash_area_id, struct boot_swap_state *state);
+
 #define BOOT_MAGIC_ARR_SZ \
     (sizeof boot_img_magic / sizeof boot_img_magic[0])
 

boot/bootutil/src/bootutil_priv.h

@@ -146,14 +146,6 @@ struct boot_status {
 
 extern const uint32_t boot_img_magic[4];
 
-struct boot_swap_state {
-    uint8_t magic;      /* One of the BOOT_MAGIC_[...] values. */
-    uint8_t swap_type;  /* One of the BOOT_SWAP_TYPE_[...] values. */
-    uint8_t copy_done;  /* One of the BOOT_FLAG_[...] values. */
-    uint8_t image_ok;   /* One of the BOOT_FLAG_[...] values. */
-    uint8_t image_num;  /* Boot status belongs to this image */
-};
-
 #ifdef MCUBOOT_IMAGE_NUMBER
 #define BOOT_IMAGE_NUMBER          MCUBOOT_IMAGE_NUMBER
 #else

boot/bootutil/src/bootutil_public.c

@@ -295,9 +295,6 @@ boot_read_swap_state(const struct flash_area *fap,
     return boot_read_image_ok(fap, &state->image_ok);
 }
 
-/**
- * Reads the image trailer from the scratch area.
- */
 int
 boot_read_swap_state_by_id(int flash_area_id, struct boot_swap_state *state)
 {