mgmt/mcumgr: Don't add unused slots in img_mgmt_flash_area_id

The img_mgmt_flash_area_id would add processing of
slot2_partition and slot3_partition if they only exist, even if
not used at all.

Signed-off-by: Dominik Ermel <[email protected]>

Author: de-nordic

subsys/mgmt/mcumgr/grp/img_mgmt/src/zephyr_img_mgmt.c

@@ -34,15 +34,37 @@ BUILD_ASSERT(CONFIG_MCUMGR_GRP_IMG_UPDATABLE_IMAGE_NUMBER == 1 ||
 	      FIXED_PARTITION_EXISTS(SLOT3_PARTITION)),
 	     "Missing partitions?");
 
+#if defined(CONFIG_MCUMGR_GRP_IMG_DIRECT_UPLOAD) &&		\
+	!(CONFIG_MCUMGR_GRP_IMG_UPDATABLE_IMAGE_NUMBER > 1)
+/* In case when direct upload is enabled, slot2 and slot3 are optional
+ * as long as there is support for one application image only.
+ */
+#define ADD_SLOT_2_CONDITION FIXED_PARTITION_EXISTS(SLOT2_PARTITION)
+#define ADD_SLOT_3_CONDITION FIXED_PARTITION_EXISTS(SLOT3_PARTITION)
+#elif (CONFIG_MCUMGR_GRP_IMG_UPDATABLE_IMAGE_NUMBER > 1)
+/* For more than one application image slot2 and slot3 are required. */
+#define ADD_SLOT_2_CONDITION 1
+#define ADD_SLOT_3_CONDITION 1
+#else
+/* If neither in direct upload mode nor more than one application image
+ * is supported, then slot2 and slot3 support is useless.
+ */
+#define ADD_SLOT_2_CONDITION 0
+#define ADD_SLOT_3_CONDITION 0
+#endif
+
 static int
 img_mgmt_slot_to_image(int slot)
 {
 	switch (slot) {
 	case 0:
 	case 1:
 		return 0;
-#if FIXED_PARTITION_EXISTS(SLOT2_PARTITION) && FIXED_PARTITION_EXISTS(SLOT2_PARTITION)
+#if ADD_SLOT_2_CONDITION
 	case 2:
+		return 1;
+#endif
+#if ADD_SLOT_3_CONDITION
 	case 3:
 		return 1;
 #endif
@@ -141,13 +163,13 @@ img_mgmt_flash_area_id(int slot)
 		fa_id = FIXED_PARTITION_ID(SLOT1_PARTITION);
 		break;
 
-#if FIXED_PARTITION_EXISTS(SLOT2_PARTITION)
+#if ADD_SLOT_2_CONDITION
 	case 2:
 		fa_id = FIXED_PARTITION_ID(SLOT2_PARTITION);
 		break;
 #endif
 
-#if FIXED_PARTITION_EXISTS(SLOT3_PARTITION)
+#if ADD_SLOT_3_CONDITION
 	case 3:
 		fa_id = FIXED_PARTITION_ID(SLOT3_PARTITION);
 		break;