Boot: Extend flash layout for multiple images

This patch extends the flash layout of supported platforms, and also
introduces the BOOT_IMAGE_NUMBER macro and the current_image variable
in MCUBoot to support multiple updatable images.

The FLASH_AREA_IMAGE_PRIMARY/SECONDARY object-like macros are replaced
with function-like ones and therefore some functions have been updated,
because the labels of a switch statement and the initialization
values of objects with static storage duration have to be constant
expressions.

Change-Id: Ic4425c9034f877fe2b83d80a3df211232f14a09f
Signed-off-by: David Vincze <david.vincze@arm.com>
diff --git a/bl2/ext/mcuboot/bootutil/src/bootutil_misc.c b/bl2/ext/mcuboot/bootutil/src/bootutil_misc.c
index c076c31..94fdc30 100644
--- a/bl2/ext/mcuboot/bootutil/src/bootutil_misc.c
+++ b/bl2/ext/mcuboot/bootutil/src/bootutil_misc.c
@@ -164,13 +164,12 @@
 int
 boot_status_entries(const struct flash_area *fap)
 {
-    switch (fap->fa_id) {
-    case FLASH_AREA_IMAGE_PRIMARY:
-    case FLASH_AREA_IMAGE_SECONDARY:
-        return BOOT_STATUS_STATE_COUNT * BOOT_STATUS_MAX_ENTRIES;
-    case FLASH_AREA_IMAGE_SCRATCH:
+    if (fap->fa_id == FLASH_AREA_IMAGE_SCRATCH) {
         return BOOT_STATUS_STATE_COUNT;
-    default:
+    } else if ((fap->fa_id == FLASH_AREA_IMAGE_PRIMARY) ||
+               (fap->fa_id == FLASH_AREA_IMAGE_SECONDARY)) {
+        return BOOT_STATUS_STATE_COUNT * BOOT_STATUS_MAX_ENTRIES;
+    } else {
         return BOOT_EBADARGS;
     }
 }
@@ -284,16 +283,14 @@
     const struct flash_area *fap;
     int rc;
 
-    switch (flash_area_id) {
-    case FLASH_AREA_IMAGE_SCRATCH:
-    case FLASH_AREA_IMAGE_PRIMARY:
-    case FLASH_AREA_IMAGE_SECONDARY:
+    if (flash_area_id == FLASH_AREA_IMAGE_SCRATCH ||
+        flash_area_id == FLASH_AREA_IMAGE_PRIMARY ||
+        flash_area_id == FLASH_AREA_IMAGE_SECONDARY) {
         rc = flash_area_open(flash_area_id, &fap);
         if (rc != 0) {
             return BOOT_EFLASH;
         }
-        break;
-    default:
+    } else {
         return BOOT_EBADARGS;
     }
 
diff --git a/bl2/ext/mcuboot/bootutil/src/bootutil_priv.h b/bl2/ext/mcuboot/bootutil/src/bootutil_priv.h
index 5a38dac..9ea1a24 100644
--- a/bl2/ext/mcuboot/bootutil/src/bootutil_priv.h
+++ b/bl2/ext/mcuboot/bootutil/src/bootutil_priv.h
@@ -119,6 +119,12 @@
     uint8_t image_num;  /* Boot status belongs to this image */
 };
 
+#ifdef MCUBOOT_IMAGE_NUMBER
+#define BOOT_IMAGE_NUMBER       MCUBOOT_IMAGE_NUMBER
+#else
+#define BOOT_IMAGE_NUMBER       1
+#endif
+
 /*
  * Extract the swap type and image number from image trailers's swap_info
  * field.
@@ -285,23 +291,19 @@
     int num_sectors = BOOT_MAX_IMG_SECTORS;
     int rc;
 
-    switch (flash_area) {
-    case FLASH_AREA_IMAGE_PRIMARY:
+    if (flash_area == FLASH_AREA_IMAGE_PRIMARY) {
         rc = flash_area_to_sectors(flash_area, &num_sectors,
                                    state->imgs[BOOT_PRIMARY_SLOT].sectors);
         state->imgs[BOOT_PRIMARY_SLOT].num_sectors = (size_t)num_sectors;
-        break;
-    case FLASH_AREA_IMAGE_SECONDARY:
+    } else if (flash_area == FLASH_AREA_IMAGE_SECONDARY) {
         rc = flash_area_to_sectors(flash_area, &num_sectors,
                                    state->imgs[BOOT_SECONDARY_SLOT].sectors);
         state->imgs[BOOT_SECONDARY_SLOT].num_sectors = (size_t)num_sectors;
-        break;
-    case FLASH_AREA_IMAGE_SCRATCH:
+    } else if (flash_area == FLASH_AREA_IMAGE_SCRATCH) {
         rc = flash_area_to_sectors(flash_area, &num_sectors,
                                    state->scratch.sectors);
         state->scratch.num_sectors = (size_t)num_sectors;
-        break;
-    default:
+    } else {
         return BOOT_EFLASH;
     }
 
@@ -333,24 +335,19 @@
     size_t *out_num_sectors;
     int rc;
 
-    switch (flash_area) {
-    case FLASH_AREA_IMAGE_PRIMARY:
-        num_sectors = BOOT_MAX_IMG_SECTORS;
+    num_sectors = BOOT_MAX_IMG_SECTORS;
+
+    if (flash_area == FLASH_AREA_IMAGE_PRIMARY) {
         out_sectors = state->imgs[BOOT_PRIMARY_SLOT].sectors;
         out_num_sectors = &state->imgs[BOOT_PRIMARY_SLOT].num_sectors;
-        break;
-    case FLASH_AREA_IMAGE_SECONDARY:
-        num_sectors = BOOT_MAX_IMG_SECTORS;
+    } else if (flash_area == FLASH_AREA_IMAGE_SECONDARY) {
         out_sectors = state->imgs[BOOT_SECONDARY_SLOT].sectors;
         out_num_sectors = &state->imgs[BOOT_SECONDARY_SLOT].num_sectors;
-        break;
-    case FLASH_AREA_IMAGE_SCRATCH:
-        num_sectors = BOOT_MAX_IMG_SECTORS;
+    } else if (flash_area == FLASH_AREA_IMAGE_SCRATCH) {
         out_sectors = state->scratch.sectors;
         out_num_sectors = &state->scratch.num_sectors;
-        break;
-    default:
-        return -1;
+    } else {
+        return BOOT_EFLASH;
     }
 
     rc = flash_area_get_sectors(flash_area, &num_sectors, out_sectors);
diff --git a/bl2/ext/mcuboot/bootutil/src/loader.c b/bl2/ext/mcuboot/bootutil/src/loader.c
index 80789e5..c7c7173 100644
--- a/bl2/ext/mcuboot/bootutil/src/loader.c
+++ b/bl2/ext/mcuboot/bootutil/src/loader.c
@@ -47,6 +47,7 @@
 #include "bootutil/bootutil_log.h"
 
 static struct boot_loader_state boot_data;
+uint8_t current_image = 0;
 
 #if !defined(MCUBOOT_NO_SWAP) && !defined(MCUBOOT_RAM_LOADING)
 
@@ -977,18 +978,20 @@
     uint32_t total_sz;
     uint32_t off;
     uint32_t sz;
+    int fa_id_primary;
+    int fa_id_secondary;
     int rc;
 
     BOOT_LOG_DBG("erasing trailer; fa_id=%d", fap->fa_id);
 
-    switch (fap->fa_id) {
-    case FLASH_AREA_IMAGE_PRIMARY:
+    fa_id_primary   = flash_area_id_from_image_slot(BOOT_PRIMARY_SLOT);
+    fa_id_secondary = flash_area_id_from_image_slot(BOOT_SECONDARY_SLOT);
+
+    if (fap->fa_id == fa_id_primary) {
         slot = BOOT_PRIMARY_SLOT;
-        break;
-    case FLASH_AREA_IMAGE_SECONDARY:
+    } else if (fap->fa_id == fa_id_secondary) {
         slot = BOOT_SECONDARY_SLOT;
-        break;
-    default:
+    } else {
         return BOOT_EFLASH;
     }
 
diff --git a/bl2/ext/mcuboot/flash_map.c b/bl2/ext/mcuboot/flash_map.c
index 31a9d74..5cbb824 100644
--- a/bl2/ext/mcuboot/flash_map.c
+++ b/bl2/ext/mcuboot/flash_map.c
@@ -64,28 +64,48 @@
     {
         .magic = FLASH_MAP_ENTRY_MAGIC,
         .area = {
-            .fa_id = FLASH_AREA_IMAGE_PRIMARY,
+            .fa_id = FLASH_AREA_0_ID,
             .fa_device_id = FLASH_DEVICE_ID,
-            .fa_off = FLASH_AREA_IMAGE_PRIMARY_OFFSET,
-            .fa_size = FLASH_AREA_IMAGE_PRIMARY_SIZE,
+            .fa_off = FLASH_AREA_0_OFFSET,
+            .fa_size = FLASH_AREA_0_SIZE,
         },
     },
     {
         .magic = FLASH_MAP_ENTRY_MAGIC,
         .area = {
-            .fa_id = FLASH_AREA_IMAGE_SECONDARY,
+            .fa_id = FLASH_AREA_2_ID,
             .fa_device_id = FLASH_DEVICE_ID,
-            .fa_off = FLASH_AREA_IMAGE_SECONDARY_OFFSET,
-            .fa_size = FLASH_AREA_IMAGE_SECONDARY_SIZE,
+            .fa_off = FLASH_AREA_2_OFFSET,
+            .fa_size = FLASH_AREA_2_SIZE,
+        },
+    },
+#if (MCUBOOT_IMAGE_NUMBER == 2)
+    {
+        .magic = FLASH_MAP_ENTRY_MAGIC,
+        .area = {
+            .fa_id = FLASH_AREA_1_ID,
+            .fa_device_id = FLASH_DEVICE_ID,
+            .fa_off = FLASH_AREA_1_OFFSET,
+            .fa_size = FLASH_AREA_1_SIZE,
         },
     },
     {
         .magic = FLASH_MAP_ENTRY_MAGIC,
         .area = {
-            .fa_id = FLASH_AREA_IMAGE_SCRATCH,
+            .fa_id = FLASH_AREA_3_ID,
             .fa_device_id = FLASH_DEVICE_ID,
-            .fa_off = FLASH_AREA_IMAGE_SCRATCH_OFFSET,
-            .fa_size = FLASH_AREA_IMAGE_SCRATCH_SIZE,
+            .fa_off = FLASH_AREA_3_OFFSET,
+            .fa_size = FLASH_AREA_3_SIZE,
+        },
+    },
+#endif
+    {
+        .magic = FLASH_MAP_ENTRY_MAGIC,
+        .area = {
+            .fa_id = FLASH_AREA_SCRATCH_ID,
+            .fa_device_id = FLASH_DEVICE_ID,
+            .fa_off = FLASH_AREA_SCRATCH_OFFSET,
+            .fa_size = FLASH_AREA_SCRATCH_SIZE,
         },
     }
 };
@@ -251,9 +271,12 @@
  */
 int flash_area_id_from_image_slot(int slot)
 {
-    static const int area_id_tab[] = {FLASH_AREA_IMAGE_PRIMARY,
-                                      FLASH_AREA_IMAGE_SECONDARY,
-                                      FLASH_AREA_IMAGE_SCRATCH};
+#if (MCUBOOT_IMAGE_NUMBER == 1)
+    static
+#endif
+    const int area_id_tab[] = {FLASH_AREA_IMAGE_PRIMARY,
+                               FLASH_AREA_IMAGE_SECONDARY,
+                               FLASH_AREA_IMAGE_SCRATCH};
 
     if (slot >= 0 && slot < ARRAY_SIZE(area_id_tab)) {
         return area_id_tab[slot];
@@ -264,15 +287,15 @@
 
 int flash_area_id_to_image_slot(int area_id)
 {
-    switch (area_id) {
-    case FLASH_AREA_IMAGE_PRIMARY:
+    if (area_id == FLASH_AREA_IMAGE_PRIMARY) {
         return 0;
-    case FLASH_AREA_IMAGE_SECONDARY:
-        return 1;
-    default:
-        BOOT_LOG_ERR("invalid flash area ID");
-        return -1;
     }
+    if (area_id == FLASH_AREA_IMAGE_SECONDARY) {
+        return 1;
+    }
+
+    BOOT_LOG_ERR("invalid flash area ID");
+    return -1;
 }
 
 static int validate_idx(int idx, uint32_t *off, uint32_t *len)
@@ -283,17 +306,27 @@
      */
 
     switch (idx) {
-    case FLASH_AREA_IMAGE_PRIMARY:
-        *off = FLASH_AREA_IMAGE_PRIMARY_OFFSET;
-        *len = FLASH_AREA_IMAGE_PRIMARY_SIZE;
+    case FLASH_AREA_0_ID:
+        *off = FLASH_AREA_0_OFFSET;
+        *len = FLASH_AREA_0_SIZE;
         break;
-    case FLASH_AREA_IMAGE_SECONDARY:
-        *off = FLASH_AREA_IMAGE_SECONDARY_OFFSET;
-        *len = FLASH_AREA_IMAGE_SECONDARY_SIZE;
+    case FLASH_AREA_2_ID:
+        *off = FLASH_AREA_2_OFFSET;
+        *len = FLASH_AREA_2_SIZE;
         break;
-    case FLASH_AREA_IMAGE_SCRATCH:
-        *off = FLASH_AREA_IMAGE_SCRATCH_OFFSET;
-        *len = FLASH_AREA_IMAGE_SCRATCH_SIZE;
+#if (MCUBOOT_IMAGE_NUMBER == 2)
+    case FLASH_AREA_1_ID:
+        *off = FLASH_AREA_1_OFFSET;
+        *len = FLASH_AREA_1_SIZE;
+        break;
+    case FLASH_AREA_3_ID:
+        *off = FLASH_AREA_3_OFFSET;
+        *len = FLASH_AREA_3_SIZE;
+        break;
+#endif
+    case FLASH_AREA_SCRATCH_ID:
+        *off = FLASH_AREA_SCRATCH_OFFSET;
+        *len = FLASH_AREA_SCRATCH_SIZE;
         break;
     default:
         BOOT_LOG_ERR("unknown flash area %d", idx);
diff --git a/bl2/ext/mcuboot/include/flash_map/flash_map.h b/bl2/ext/mcuboot/include/flash_map/flash_map.h
index 1c40c3d..3f00a5d 100644
--- a/bl2/ext/mcuboot/include/flash_map/flash_map.h
+++ b/bl2/ext/mcuboot/include/flash_map/flash_map.h
@@ -50,9 +50,27 @@
  */
 #include <inttypes.h>
 
-#define FLASH_AREA_IMAGE_PRIMARY      1
-#define FLASH_AREA_IMAGE_SECONDARY    2
-#define FLASH_AREA_IMAGE_SCRATCH      3
+extern uint8_t current_image;
+
+#if (MCUBOOT_IMAGE_NUMBER == 1)
+#define FLASH_AREA_IMAGE_PRIMARY     FLASH_AREA_0_ID
+#define FLASH_AREA_IMAGE_SECONDARY   FLASH_AREA_2_ID
+#elif (MCUBOOT_IMAGE_NUMBER == 2)
+/* MCUBoot currently supports only up to 2 updatable firmware images.
+ * If the number of the current image is greater than MCUBOOT_IMAGE_NUMBER - 1
+ * then a dummy value will be assigned to the flash area macros.
+ */
+#define FLASH_AREA_IMAGE_PRIMARY     ((current_image == 0) ? FLASH_AREA_0_ID : \
+                                      (current_image == 1) ? FLASH_AREA_1_ID : \
+                                                             255 )
+#define FLASH_AREA_IMAGE_SECONDARY   ((current_image == 0) ? FLASH_AREA_2_ID : \
+                                      (current_image == 1) ? FLASH_AREA_3_ID : \
+                                                             255 )
+#else
+#error "Image slot and flash area mapping is not defined"
+#endif
+
+#define FLASH_AREA_IMAGE_SCRATCH     FLASH_AREA_SCRATCH_ID
 
 /**
  * @brief Structure describing an area on a flash device.
diff --git a/bl2/ext/mcuboot/include/target.h b/bl2/ext/mcuboot/include/target.h
index 97930d7..728541c 100644
--- a/bl2/ext/mcuboot/include/target.h
+++ b/bl2/ext/mcuboot/include/target.h
@@ -21,28 +21,46 @@
 #error "FLASH_AREA_IMAGE_SECTOR_SIZE must be defined by the target"
 #endif
 
-#ifndef FLASH_AREA_IMAGE_PRIMARY_OFFSET
-#error "FLASH_AREA_IMAGE_PRIMARY_OFFSET must be defined by the target"
+#ifndef FLASH_AREA_0_OFFSET
+#error "FLASH_AREA_0_OFFSET must be defined by the target"
 #endif
 
-#ifndef FLASH_AREA_IMAGE_PRIMARY_SIZE
-#error "FLASH_AREA_IMAGE_PRIMARY_SIZE must be defined by the target"
+#ifndef FLASH_AREA_0_SIZE
+#error "FLASH_AREA_0_SIZE must be defined by the target"
 #endif
 
-#ifndef FLASH_AREA_IMAGE_SECONDARY_OFFSET
-#error "FLASH_AREA_IMAGE_SECONDARY_OFFSET must be defined by the target"
+#ifndef FLASH_AREA_2_OFFSET
+#error "FLASH_AREA_2_OFFSET must be defined by the target"
 #endif
 
-#ifndef FLASH_AREA_IMAGE_SECONDARY_SIZE
-#error "FLASH_AREA_IMAGE_SECONDARY_SIZE must be defined by the target"
+#ifndef FLASH_AREA_2_SIZE
+#error "FLASH_AREA_2_SIZE must be defined by the target"
 #endif
 
-#ifndef FLASH_AREA_IMAGE_SCRATCH_OFFSET
-#error "FLASH_AREA_IMAGE_SCRATCH_OFFSET must be defined by the target"
+#if (MCUBOOT_IMAGE_NUMBER == 2)
+#ifndef FLASH_AREA_1_OFFSET
+#error "FLASH_AREA_1_OFFSET must be defined by the target"
 #endif
 
-#ifndef FLASH_AREA_IMAGE_SCRATCH_SIZE
-#error "FLASH_AREA_IMAGE_SCRATCH_SIZE must be defined by the target"
+#ifndef FLASH_AREA_1_SIZE
+#error "FLASH_AREA_1_SIZE must be defined by the target"
+#endif
+
+#ifndef FLASH_AREA_3_OFFSET
+#error "FLASH_AREA_3_OFFSET must be defined by the target"
+#endif
+
+#ifndef FLASH_AREA_3_SIZE
+#error "FLASH_AREA_3_SIZE must be defined by the target"
+#endif
+#endif /* (MCUBOOT_IMAGE_NUMBER == 2) */
+
+#ifndef FLASH_AREA_SCRATCH_OFFSET
+#error "FLASH_AREA_SCRATCH_OFFSET must be defined by the target"
+#endif
+
+#ifndef FLASH_AREA_SCRATCH_SIZE
+#error "FLASH_AREA_SCRATCH_SIZE must be defined by the target"
 #endif
 
 #ifndef FLASH_DEV_NAME
@@ -57,4 +75,4 @@
 #error "BOOT_MAX_IMG_SECTORS must be defined by the target"
 #endif
 
-#endif
+#endif /* H_TARGETS_TARGET_ */