WIP: RFC: Preliminary work on flash_area open once.

boot/zephyr/flash_map_extended.c

@@ -135,3 +135,33 @@ __weak uint8_t flash_area_erased_val(const struct flash_area *fap)
     (void)fap;
     return ERASED_VAL;
 }
+
+int flash_area_get_sectors_fa(const struct flash_area *fa, uint32_t *count,
+    struct flash_sector *ret)
+{
+    off_t fa_off = fa->fa_off;
+    off_t offset = 0;
+    size_t fa_size = fa->fa_size;
+    int max_sectors = *count;
+    int sector_idx = 0;
+    int rc = 0;
+
+    while (rc == 0 && sector_idx < max_sectors && offset < fa_size) {
+        struct flash_pages_info fpi;
+
+        rc = flash_get_page_info_by_offs(fa->fa_dev, fa_off + offset, &fpi);
+
+        if (rc == 0) {
+            ret[sector_idx].fs_off = fpi.start_offset - fa_off;
+            ret[sector_idx].fs_size = fpi.size;
+            ++sector_idx;
+            offset += fpi.size;
+        }
+    }
+
+    if (sector_idx >= max_sectors && offset >= fa_size) {
+        return -ENOENT;
+    }
+
+    return rc;
+}

boot/zephyr/include/flash_map_backend/flash_map_backend.h

@@ -62,6 +62,21 @@ int flash_area_id_to_multi_image_slot(int image_index, int area_id);
  */
 int flash_area_sector_from_off(off_t off, struct flash_sector *sector);
 
+/* Get sectors for given flash_area object. This function is similar to
+ * flash_area_get_sectors but takes flash_area object pointer instead
+ * of flash area identifier.
+ *
+ * @param fa    pointer to flash_area object.
+ * @param count in: size of array for returned sectors, out: number
+ *              of sectors filled in.
+ * @param ret   array of sectors.
+ *
+ * Returns 0 on success, -ERANGE when there is not enough space in
+ * @p ret for sector information; other negative errno code.
+ */
+int flash_area_get_sectors_fa(const struct flash_area *fa, uint32_t *count,
+                              struct flash_sector *ret);
+
 static inline uint32_t flash_area_get_off(const struct flash_area *fa)
 {
 	return (uint32_t)fa->fa_off;