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.