[nrf noup] bootutil: loader.c: Fix network core update external flash

Using sequential updates on the nRF53 with external flash would cause
network core updates to fail. This is because the update would be
located in the external flash which is network core cannot access. This
fixes the issue by copying the data from the external flash into RAM of
the application core which can be read by the network core.

This commit also contains some minor renaming to align with the naming
scheme used in the `loader.c` file for flash areas.

Ref: NCSDK-21379

Signed-off-by: Sigvart Hovland <[email protected]>

Author: sigvartmh

boot/bootutil/src/loader.c

@@ -52,6 +52,10 @@
 #include <dfu/pcd.h>
 #endif
 
+#if defined(CONFIG_FLASH_SIMULATOR)
+#include <zephyr/drivers/flash/flash_simulator.h>
+#endif
+
 #ifdef MCUBOOT_ENC_IMAGES
 #include "bootutil/enc_key.h"
 #endif
@@ -936,7 +940,7 @@ boot_validated_swap_type(struct boot_loader_state *state,
     bool upgrade_valid = false;
 
 #if defined(PM_S1_ADDRESS) || defined(CONFIG_SOC_NRF5340_CPUAPP)
-    const struct flash_area *secondary_fa =
+    const struct flash_area *fap_secondary_slot =
         BOOT_IMG_AREA(state, BOOT_SECONDARY_SLOT);
     struct image_header *hdr = boot_img_hdr(state, BOOT_SECONDARY_SLOT);
     uint32_t reset_addr = 0;
@@ -950,7 +954,7 @@ boot_validated_swap_type(struct boot_loader_state *state,
      */
 
     if (hdr->ih_magic == IMAGE_MAGIC) {
-        rc = flash_area_read(secondary_fa, hdr->ih_hdr_size +
+        rc = flash_area_read(fap_secondary_slot, hdr->ih_hdr_size +
                              sizeof(uint32_t), &reset_addr,
                              sizeof(reset_addr));
         if (rc != 0) {
@@ -1018,24 +1022,52 @@ boot_validated_swap_type(struct boot_loader_state *state,
          * available
          */
         if (upgrade_valid && reset_addr > PM_CPUNET_B0N_ADDRESS) {
-            struct image_header *hdr = (struct image_header *)secondary_fa->fa_off;
+            uint32_t fw_size = hdr->ih_img_size;
             uint32_t vtable_addr = (uint32_t)hdr + hdr->ih_hdr_size;
             uint32_t *net_core_fw_addr = (uint32_t *)(vtable_addr);
-            uint32_t fw_size = hdr->ih_img_size;
+#if defined(CONFIG_PM_EXTERNAL_FLASH_MCUBOOT_SECONDARY)
+            size_t mock_size;
+            uint32_t *flash_sim_addr = flash_simulator_get_memory(NULL, &mock_size);
+            /* Direct copy from flash to mocked flash in SRAM. */
+            rc = flash_area_read(fap_secondary_slot, hdr->ih_hdr_size , (void *)(flash_sim_addr),
+                            fw_size);
+            if (rc != 0) {
+                    BOOT_LOG_INF("Error whilst copying image from Flash to SRAM(flash_sim): %d",
+                                 rc);
+                    return BOOT_SWAP_TYPE_FAIL;
+            }
+            net_core_fw_addr = flash_sim_addr;
+#endif
             BOOT_LOG_INF("Starting network core update");
             rc = pcd_network_core_update(net_core_fw_addr, fw_size);
 
             if (rc != 0) {
                 swap_type = BOOT_SWAP_TYPE_FAIL;
             } else {
                 BOOT_LOG_INF("Done updating network core");
+
 #if defined(MCUBOOT_SWAP_USING_SCRATCH) || defined(MCUBOOT_SWAP_USING_MOVE)
                 /* swap_erase_trailer_sectors is undefined if upgrade only
                  * method is used. There is no need to erase sectors, because
                  * the image cannot be reverted.
                  */
-                rc = swap_erase_trailer_sectors(state,
-                        secondary_fa);
+                rc = swap_erase_trailer_sectors(state, fap_secondary_slot);
+                if (rc != 0) {
+                        BOOT_LOG_DBG("Unable to erase swap trailer info");
+                }
+#elif defined(MCUBOOT_OVERWRITE_ONLY)
+                size_t last_sector = boot_img_num_sectors(state, BOOT_SECONDARY_SLOT) - 1;
+                rc = boot_erase_region(fap_secondary_slot,
+                                boot_img_sector_off(state, BOOT_SECONDARY_SLOT,
+                                        last_sector),
+                                boot_img_sector_size(state, BOOT_SECONDARY_SLOT,
+                                        last_sector));
+                if (rc != 0) {
+                        /* This will cause the network update to happen again
+                         * on the next reboot
+                         */
+                        BOOT_LOG_DBG("Unable to erase trailer info");
+                }
 #endif
                 swap_type = BOOT_SWAP_TYPE_NONE;
             }