boot: zephyr: Add check for unexpected flash sector size

boot/bootutil/src/swap_move.c

@@ -298,6 +298,26 @@ boot_slots_compatible(struct boot_loader_state *state)
         }
     }
 
+#ifdef MCUBOOT_SLOT0_EXPECTED_ERASE_SIZE
+    if (sector_sz_pri != MCUBOOT_SLOT0_EXPECTED_ERASE_SIZE) {
+        BOOT_LOG_DBG("Discrepancy, slot0 expected erase size: %d, actual: %d",
+                     MCUBOOT_SLOT0_EXPECTED_ERASE_SIZE, sector_sz_pri);
+    }
+#endif
+#ifdef MCUBOOT_SLOT1_EXPECTED_ERASE_SIZE
+    if (sector_sz_sec != MCUBOOT_SLOT1_EXPECTED_ERASE_SIZE) {
+        BOOT_LOG_DBG("Discrepancy, slot1 expected erase size: %d, actual: %d",
+                     MCUBOOT_SLOT1_EXPECTED_ERASE_SIZE, sector_sz_sec);
+    }
+#endif
+
+#if defined(MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE) || defined(MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE)
+    if (!swap_write_block_size_check(state)) {
+        BOOT_LOG_WRN("Cannot upgrade: slot write sizes are not compatible");
+        return 0;
+    }
+#endif
+
     if (num_sectors_pri > num_sectors_sec) {
         if (sector_sz_pri != boot_img_sector_size(state, BOOT_PRIMARY_SLOT, i)) {
             BOOT_LOG_WRN("Cannot upgrade: not same sector layout");

boot/bootutil/src/swap_priv.h

@@ -101,6 +101,19 @@ static inline size_t boot_scratch_area_size(const struct boot_loader_state *stat
 
 #endif /* defined(MCUBOOT_SWAP_USING_SCRATCH) || defined(MCUBOOT_SWAP_USING_MOVE) */
 
+#if defined(MCUBOOT_SWAP_USING_MOVE)
+/**
+ * Check if device write block sizes are as expected, function should emit an error if there is
+ * a problem. If true is returned, the slots are marked as compatible, otherwise the slots are
+ * marked as incompatible.
+ *
+ * Requires MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE be set to the write block size of image 0 primary
+ * slot and MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE be set to the write block size of image 0 secondary
+ * slot.
+ */
+bool swap_write_block_size_check(struct boot_loader_state *state);
+#endif /* defined(MCUBOOT_SWAP_USING_MOVE) */
+
 /**
  * Returns the maximum size of an application that can be loaded to a slot.
  */

boot/zephyr/CMakeLists.txt

@@ -379,13 +379,43 @@ function(dt_get_parent node)
   set(${node} "${${node}}" PARENT_SCOPE)
 endfunction()
 
-if(CONFIG_BOOT_MAX_IMG_SECTORS_AUTO)
-  dt_nodelabel(slot0_flash NODELABEL "slot0_partition")
-  dt_prop(slot0_size PATH "${slot0_flash}" PROPERTY "reg" INDEX 1)
-  dt_get_parent(slot0_flash)
-  dt_get_parent(slot0_flash)
-  dt_prop(erase_size_slot0 PATH "${slot0_flash}" PROPERTY "erase-block-size")
+dt_nodelabel(slot0_flash NODELABEL "slot0_partition")
+dt_prop(slot0_size PATH "${slot0_flash}" PROPERTY "reg" INDEX 1)
+dt_get_parent(slot0_flash)
+dt_get_parent(slot0_flash)
+dt_prop(erase_size_slot0 PATH "${slot0_flash}" PROPERTY "erase-block-size")
+dt_prop(write_size_slot0 PATH "${slot0_flash}" PROPERTY "write-block-size")
+
+if(CONFIG_BOOT_SWAP_USING_MOVE)
+  if(DEFINED erase_size_slot0)
+    zephyr_compile_definitions("MCUBOOT_SLOT0_EXPECTED_ERASE_SIZE=${erase_size_slot0}")
+  endif()
+
+  if(DEFINED write_size_slot0)
+    zephyr_compile_definitions("MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE=${write_size_slot0}")
+  endif()
+endif()
+
+if(NOT CONFIG_SINGLE_APPLICATION_SLOT)
+  dt_nodelabel(slot1_flash NODELABEL "slot1_partition")
+  dt_prop(slot1_size PATH "${slot1_flash}" PROPERTY "reg" INDEX 1)
+  dt_get_parent(slot1_flash)
+  dt_get_parent(slot1_flash)
+  dt_prop(erase_size_slot1 PATH "${slot1_flash}" PROPERTY "erase-block-size")
+  dt_prop(write_size_slot1 PATH "${slot1_flash}" PROPERTY "write-block-size")
+
+  if(CONFIG_BOOT_SWAP_USING_MOVE)
+    if(DEFINED erase_size_slot1)
+      zephyr_compile_definitions("MCUBOOT_SLOT1_EXPECTED_ERASE_SIZE=${erase_size_slot1}")
+    endif()
 
+    if(DEFINED write_size_slot1)
+      zephyr_compile_definitions("MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE=${write_size_slot1}")
+    endif()
+  endif()
+endif()
+
+if(CONFIG_BOOT_MAX_IMG_SECTORS_AUTO)
   if(NOT DEFINED slot0_size)
     message(WARNING "Unable to determine size of slot0 partition, cannot calculate minimum sector usage")
   elseif(NOT DEFINED erase_size_slot0)
@@ -395,12 +425,6 @@ if(CONFIG_BOOT_MAX_IMG_SECTORS_AUTO)
   endif()
 
   if(NOT CONFIG_SINGLE_APPLICATION_SLOT)
-    dt_nodelabel(slot1_flash NODELABEL "slot1_partition")
-    dt_prop(slot1_size PATH "${slot1_flash}" PROPERTY "reg" INDEX 1)
-    dt_get_parent(slot1_flash)
-    dt_get_parent(slot1_flash)
-    dt_prop(erase_size_slot1 PATH "${slot1_flash}" PROPERTY "erase-block-size")
-
     if(NOT DEFINED slot1_size)
       message(WARNING "Unable to determine size of slot1 partition, cannot calculate minimum sector usage")
     elseif(NOT DEFINED erase_size_slot1)
@@ -422,6 +446,10 @@ if(CONFIG_BOOT_MAX_IMG_SECTORS_AUTO)
   endif()
 endif()
 
+if((CONFIG_BOOT_SWAP_USING_SCRATCH OR CONFIG_BOOT_SWAP_USING_MOVE) AND (DEFINED write_size_slot0 OR DEFINED write_size_slot1))
+  zephyr_library_sources(flash_check.c)
+endif()
+
 if(SYSBUILD)
   if(CONFIG_SINGLE_APPLICATION_SLOT OR CONFIG_BOOT_FIRMWARE_LOADER OR CONFIG_BOOT_SWAP_USING_SCRATCH OR CONFIG_BOOT_SWAP_USING_MOVE OR CONFIG_BOOT_UPGRADE_ONLY OR CONFIG_BOOT_DIRECT_XIP OR CONFIG_BOOT_RAM_LOAD)
     # TODO: RAM LOAD support

boot/zephyr/flash_check.c

@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/flash.h>
+
+#include <../../bootutil/src/bootutil_priv.h>
+#include "bootutil/bootutil_log.h"
+
+#include "mcuboot_config/mcuboot_config.h"
+
+#if defined(MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE) || defined(MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE)
+BOOT_LOG_MODULE_DECLARE(mcuboot);
+
+bool swap_write_block_size_check(struct boot_loader_state *state)
+{
+#ifdef MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE
+    size_t flash_write_block_size_pri;
+#endif
+#ifdef MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE
+    size_t flash_write_block_size_sec;
+#endif
+
+#ifdef MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE
+    flash_write_block_size_pri = flash_get_write_block_size(
+                                              state->imgs[0][BOOT_PRIMARY_SLOT].area->fa_dev);
+
+    if (flash_write_block_size_pri != MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE) {
+        BOOT_LOG_DBG("Discrepancy, slot0 expected write block size: %d, actual: %d",
+                     MCUBOOT_SLOT0_EXPECTED_WRITE_SIZE, flash_write_block_size_pri);
+    }
+#endif
+
+#ifdef MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE
+    flash_write_block_size_sec = flash_get_write_block_size(
+                                              state->imgs[0][BOOT_SECONDARY_SLOT].area->fa_dev);
+
+    if (flash_write_block_size_sec != MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE) {
+        BOOT_LOG_DBG("Discrepancy, slot1 expected write block size: %d, actual: %d",
+                     MCUBOOT_SLOT1_EXPECTED_WRITE_SIZE, flash_write_block_size_sec);
+    }
+#endif
+
+    return true;
+}
+#endif

docs/release-notes.d/compatible-slots.md

@@ -0,0 +1,7 @@
+- Added optional write block size checking to ensure expected
+  sizes match what is available on the hardware.
+- Added optional erase size checking to ensure expected sizes
+  match what is available on the hardware.
+- Added debug logs for zephyr to output discrepencies in erase
+  and write block sizes in dts vs actual hardware configuration
+  at run-time.