bl2/ext/mcuboot/flash_map.c - TF-M/trusted-firmware-m.git - TrustedFirmware Git Browser

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you under the Apache License, Version 2.0 (the
  * "License"); you may not use this file except in compliance
  * with the License.  You may obtain a copy of the License at
  *
  *  http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing,
  * software distributed under the License is distributed on an
  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  * KIND, either express or implied.  See the License for the
  * specific language governing permissions and limitations
  * under the License.
  */

 /*
  * Original code taken from mcuboot project at:
  * https://github.com/JuulLabs-OSS/mcuboot
  * Git SHA of the original version: 3c469bc698a9767859ed73cd0201c44161204d5c
  * Modifications are Copyright (c) 2018-2019 Arm Limited.
  */

 #include <errno.h>
 #include <stdbool.h>

 #include "target.h"
 #include "bl2_util.h"
 #include "Driver_Flash.h"

 #include <flash_map/flash_map.h>
 #include "bootutil/bootutil_log.h"

 /* Flash device name must be specified by target */
 extern ARM_DRIVER_FLASH FLASH_DEV_NAME;

 /*
  * For now, we only support one flash device.
  *
  * Pick a random device ID for it that's unlikely to collide with
  * anything "real".
  */
 #define FLASH_DEVICE_ID 100
 #define FLASH_DEVICE_BASE FLASH_BASE_ADDRESS

 #define FLASH_MAP_ENTRY_MAGIC 0xd00dbeef

 struct flash_map_entry {
     const uint32_t magic;
     const struct flash_area area;
     unsigned int ref_count;
 };

 /*
  * The flash area describes essentially the partition table of the
  * flash.  In this case, it starts with FLASH_AREA_IMAGE_PRIMARY.
  */
 static struct flash_map_entry part_map[] = {
     {
         .magic = FLASH_MAP_ENTRY_MAGIC,
         .area = {
             .fa_id = FLASH_AREA_0_ID,
             .fa_device_id = FLASH_DEVICE_ID,
             .fa_off = FLASH_AREA_0_OFFSET,
             .fa_size = FLASH_AREA_0_SIZE,
         },
     },
     {
         .magic = FLASH_MAP_ENTRY_MAGIC,
         .area = {
             .fa_id = FLASH_AREA_2_ID,
             .fa_device_id = FLASH_DEVICE_ID,
             .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_3_ID,
             .fa_device_id = FLASH_DEVICE_ID,
             .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,
         },
     }
 };

 int flash_device_base(uint8_t fd_id, uintptr_t *ret)
 {
     if (fd_id != FLASH_DEVICE_ID) {
         BOOT_LOG_ERR("invalid flash ID %d; expected %d",
                      fd_id, FLASH_DEVICE_ID);
         return -1;
     }
     *ret = FLASH_DEVICE_BASE;
     return 0;
 }

 /*
  * `open` a flash area.  The `area` in this case is not the individual
  * sectors, but describes the particular flash area in question.
  */
 int flash_area_open(uint8_t id, const struct flash_area **area)
 {
     int i;

     BOOT_LOG_DBG("area %d", id);

     for (i = 0; i < ARRAY_SIZE(part_map); i++) {
         if (id == part_map[i].area.fa_id) {
             break;
         }
     }
     if (i == ARRAY_SIZE(part_map)) {
         return -1;
     }

     *area = &part_map[i].area;
     part_map[i].ref_count++;
     return 0;
 }

 /*
  * Nothing to do on close.
  */
 void flash_area_close(const struct flash_area *area)
 {
     struct flash_map_entry *entry;

     if (!area) {
         return;
     }

     entry = CONTAINER_OF(area, struct flash_map_entry, area);
     if (entry->magic != FLASH_MAP_ENTRY_MAGIC) {
         BOOT_LOG_ERR("invalid area %p (id %u)", area, area->fa_id);
         return;
     }
     if (entry->ref_count == 0) {
         BOOT_LOG_ERR("area %u use count underflow", area->fa_id);
         return;
     }
     entry->ref_count--;
 }

 void flash_area_warn_on_open(void)
 {
     int i;
     struct flash_map_entry *entry;

     for (i = 0; i < ARRAY_SIZE(part_map); i++) {
         entry = &part_map[i];
         if (entry->ref_count) {
             BOOT_LOG_WRN("area %u has %u users",
                          entry->area.fa_id, entry->ref_count);
         }
     }
 }

 uint8_t flash_area_erased_val(const struct flash_area *area)
 {
     (void)area;

     return FLASH_DEV_NAME.GetInfo()->erased_value;
 }

 int flash_area_read(const struct flash_area *area, uint32_t off, void *dst,
                     uint32_t len)
 {
     BOOT_LOG_DBG("read area=%d, off=%#x, len=%#x", area->fa_id, off, len);
     return FLASH_DEV_NAME.ReadData(area->fa_off + off, dst, len);
 }

 int flash_area_read_is_empty(const struct flash_area *area, uint32_t off,
                              void *dst, uint32_t len)
 {
     uint32_t i;
     uint8_t *u8dst;
     int rc;

     BOOT_LOG_DBG("read_is_empty area=%d, off=%#x, len=%#x",
                  area->fa_id, off, len);

     rc = FLASH_DEV_NAME.ReadData(area->fa_off + off, dst, len);
     if(rc != 0) {
         return -1;
     }

     u8dst = (uint8_t*)dst;

     for (i = 0; i < len; i++) {
         if (u8dst[i] != flash_area_erased_val(area)) {
             return 0;
         }
     }

     return 1;
 }

 int flash_area_write(const struct flash_area *area, uint32_t off,
                      const void *src, uint32_t len)
 {
     BOOT_LOG_DBG("write area=%d, off=%#x, len=%#x", area->fa_id, off, len);
     return FLASH_DEV_NAME.ProgramData(area->fa_off + off, src, len);
 }

 int flash_area_erase(const struct flash_area *area, uint32_t off, uint32_t len)
 {
     ARM_FLASH_INFO *flash_info;
     uint32_t deleted_len = 0;
     int32_t rc = 0;

     BOOT_LOG_DBG("erase area=%d, off=%#x, len=%#x", area->fa_id, off, len);
     flash_info = FLASH_DEV_NAME.GetInfo();

     if (flash_info->sector_info == NULL) {
         /* Uniform sector layout */
         while (deleted_len < len) {
             rc = FLASH_DEV_NAME.EraseSector(area->fa_off + off);
             if (rc != 0) {
                 break;
             }
             deleted_len += flash_info->sector_size;
             off         += flash_info->sector_size;
         }
     } else {
         /* Inhomogeneous sector layout, explicitly defined
          * Currently not supported.
          */
     }

     return rc;
 }

 uint32_t flash_area_align(const struct flash_area *area)
 {
     ARM_FLASH_INFO *flash_info;

     flash_info = FLASH_DEV_NAME.GetInfo();
     return flash_info->program_unit;
 }

 /*
  * This depends on the mappings defined in sysflash.h, and assumes that the
  * primary slot, the secondary slot, and the scratch area are contiguous.
  */
 int flash_area_id_from_image_slot(int slot)
 {
 #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];
     }

     return -EINVAL; /* flash_area_open will fail on that */
 }

 int flash_area_id_to_image_slot(int area_id)
 {
     if (area_id == FLASH_AREA_IMAGE_PRIMARY) {
         return 0;
     }
     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)
 {
     /*
      * This simple layout has uniform slots, so just fill in the
      * right one.
      */

     switch (idx) {
     case FLASH_AREA_0_ID:
         *off = FLASH_AREA_0_OFFSET;
         *len = FLASH_AREA_0_SIZE;
         break;
     case FLASH_AREA_2_ID:
         *off = FLASH_AREA_2_OFFSET;
         *len = FLASH_AREA_2_SIZE;
         break;
 #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);
         return -1;
     }

     BOOT_LOG_DBG("area %d: offset=0x%x, length=0x%x, sector size=0x%x",
                  idx, *off, *len, FLASH_AREA_IMAGE_SECTOR_SIZE);
     return 0;
 }

 int flash_area_to_sectors(int idx, int *cnt, struct flash_area *ret)
 {
     uint32_t off;
     uint32_t len;
     uint32_t max_cnt = *cnt;
     uint32_t rem_len;

     if (validate_idx(idx, &off, &len)) {
         return -1;
     }

     if (*cnt < 1) {
         return -1;
     }

     rem_len = len;
     *cnt = 0;
     while (rem_len > 0 && *cnt < max_cnt) {
         if (rem_len < FLASH_AREA_IMAGE_SECTOR_SIZE) {
             BOOT_LOG_ERR("area %d size 0x%x not divisible by sector size 0x%x",
                      idx, len, FLASH_AREA_IMAGE_SECTOR_SIZE);
             return -1;
         }

         ret[*cnt].fa_id = idx;
         ret[*cnt].fa_device_id = 0;
         ret[*cnt].pad16 = 0;
         ret[*cnt].fa_off = off + (FLASH_AREA_IMAGE_SECTOR_SIZE * (*cnt));
         ret[*cnt].fa_size = FLASH_AREA_IMAGE_SECTOR_SIZE;
         *cnt = *cnt + 1;
         rem_len -= FLASH_AREA_IMAGE_SECTOR_SIZE;
     }

     if (*cnt > max_cnt) {
         BOOT_LOG_ERR("flash area %d sector count overflow", idx);
         return -1;
     }

     return 0;
 }

 /*
  * Lookup the sector map for a given flash area.  This should fill in
  * `ret` with all of the sectors in the area.  `*cnt` will be set to
  * the storage at `ret` and should be set to the final number of
  * sectors in this area.
  */
 int flash_area_get_sectors(int idx, uint32_t *cnt, struct flash_sector *ret)
 {
     uint32_t off;
     uint32_t len;
     uint32_t max_cnt = *cnt;
     uint32_t rem_len;

     if (validate_idx(idx, &off, &len)) {
         return -1;
     }

     if (*cnt < 1) {
         return -1;
     }

     rem_len = len;
     *cnt = 0;
     while (rem_len > 0 && *cnt < max_cnt) {
         if (rem_len < FLASH_AREA_IMAGE_SECTOR_SIZE) {
             BOOT_LOG_ERR("area %d size 0x%x not divisible by sector size 0x%x",
                          idx, len, FLASH_AREA_IMAGE_SECTOR_SIZE);
             return -1;
         }

         ret[*cnt].fs_off = FLASH_AREA_IMAGE_SECTOR_SIZE * (*cnt);
         ret[*cnt].fs_size = FLASH_AREA_IMAGE_SECTOR_SIZE;
         *cnt = *cnt + 1;
         rem_len -= FLASH_AREA_IMAGE_SECTOR_SIZE;
     }

     if (*cnt > max_cnt) {
         BOOT_LOG_ERR("flash area %d sector count overflow", idx);
         return -1;
     }

     return 0;
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you under the Apache License, Version 2.0 (the
	* "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing,
	* software distributed under the License is distributed on an
	* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
	* KIND, either express or implied. See the License for the
	* specific language governing permissions and limitations
	* under the License.
	*/

	/*
	* Original code taken from mcuboot project at:
	* https://github.com/JuulLabs-OSS/mcuboot
	* Git SHA of the original version: 3c469bc698a9767859ed73cd0201c44161204d5c
	* Modifications are Copyright (c) 2018-2019 Arm Limited.
	*/

	#include <errno.h>
	#include <stdbool.h>

	#include "target.h"
	#include "bl2_util.h"
	#include "Driver_Flash.h"

	#include <flash_map/flash_map.h>
	#include "bootutil/bootutil_log.h"

	/* Flash device name must be specified by target */
	extern ARM_DRIVER_FLASH FLASH_DEV_NAME;

	/*
	* For now, we only support one flash device.
	*
	* Pick a random device ID for it that's unlikely to collide with
	* anything "real".
	*/
	#define FLASH_DEVICE_ID 100
	#define FLASH_DEVICE_BASE FLASH_BASE_ADDRESS

	#define FLASH_MAP_ENTRY_MAGIC 0xd00dbeef

	struct flash_map_entry {
	const uint32_t magic;
	const struct flash_area area;
	unsigned int ref_count;
	};

	/*
	* The flash area describes essentially the partition table of the
	* flash. In this case, it starts with FLASH_AREA_IMAGE_PRIMARY.
	*/
	static struct flash_map_entry part_map[] = {
	{
	.magic = FLASH_MAP_ENTRY_MAGIC,
	.area = {
	.fa_id = FLASH_AREA_0_ID,
	.fa_device_id = FLASH_DEVICE_ID,
	.fa_off = FLASH_AREA_0_OFFSET,
	.fa_size = FLASH_AREA_0_SIZE,
	},
	},
	{
	.magic = FLASH_MAP_ENTRY_MAGIC,
	.area = {
	.fa_id = FLASH_AREA_2_ID,
	.fa_device_id = FLASH_DEVICE_ID,
	.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_3_ID,
	.fa_device_id = FLASH_DEVICE_ID,
	.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,
	},
	}
	};

	int flash_device_base(uint8_t fd_id, uintptr_t *ret)
	{
	if (fd_id != FLASH_DEVICE_ID) {
	BOOT_LOG_ERR("invalid flash ID %d; expected %d",
	fd_id, FLASH_DEVICE_ID);
	return -1;
	}
	*ret = FLASH_DEVICE_BASE;
	return 0;
	}

	/*
	* `open` a flash area. The `area` in this case is not the individual
	* sectors, but describes the particular flash area in question.
	*/
	int flash_area_open(uint8_t id, const struct flash_area **area)
	{
	int i;

	BOOT_LOG_DBG("area %d", id);

	for (i = 0; i < ARRAY_SIZE(part_map); i++) {
	if (id == part_map[i].area.fa_id) {
	break;
	}
	}
	if (i == ARRAY_SIZE(part_map)) {
	return -1;
	}

	*area = &part_map[i].area;
	part_map[i].ref_count++;
	return 0;
	}

	/*
	* Nothing to do on close.
	*/
	void flash_area_close(const struct flash_area *area)
	{
	struct flash_map_entry *entry;

	if (!area) {
	return;
	}

	entry = CONTAINER_OF(area, struct flash_map_entry, area);
	if (entry->magic != FLASH_MAP_ENTRY_MAGIC) {
	BOOT_LOG_ERR("invalid area %p (id %u)", area, area->fa_id);
	return;
	}
	if (entry->ref_count == 0) {
	BOOT_LOG_ERR("area %u use count underflow", area->fa_id);
	return;
	}
	entry->ref_count--;
	}

	void flash_area_warn_on_open(void)
	{
	int i;
	struct flash_map_entry *entry;

	for (i = 0; i < ARRAY_SIZE(part_map); i++) {
	entry = &part_map[i];
	if (entry->ref_count) {
	BOOT_LOG_WRN("area %u has %u users",
	entry->area.fa_id, entry->ref_count);
	}
	}
	}

	uint8_t flash_area_erased_val(const struct flash_area *area)
	{
	(void)area;

	return FLASH_DEV_NAME.GetInfo()->erased_value;
	}

	int flash_area_read(const struct flash_area area, uint32_t off, void dst,
	uint32_t len)
	{
	BOOT_LOG_DBG("read area=%d, off=%#x, len=%#x", area->fa_id, off, len);
	return FLASH_DEV_NAME.ReadData(area->fa_off + off, dst, len);
	}

	int flash_area_read_is_empty(const struct flash_area *area, uint32_t off,
	void *dst, uint32_t len)
	{
	uint32_t i;
	uint8_t *u8dst;
	int rc;

	BOOT_LOG_DBG("read_is_empty area=%d, off=%#x, len=%#x",
	area->fa_id, off, len);

	rc = FLASH_DEV_NAME.ReadData(area->fa_off + off, dst, len);
	if(rc != 0) {
	return -1;
	}

	u8dst = (uint8_t*)dst;

	for (i = 0; i < len; i++) {
	if (u8dst[i] != flash_area_erased_val(area)) {
	return 0;
	}
	}

	return 1;
	}

	int flash_area_write(const struct flash_area *area, uint32_t off,
	const void *src, uint32_t len)
	{
	BOOT_LOG_DBG("write area=%d, off=%#x, len=%#x", area->fa_id, off, len);
	return FLASH_DEV_NAME.ProgramData(area->fa_off + off, src, len);
	}

	int flash_area_erase(const struct flash_area *area, uint32_t off, uint32_t len)
	{
	ARM_FLASH_INFO *flash_info;
	uint32_t deleted_len = 0;
	int32_t rc = 0;

	BOOT_LOG_DBG("erase area=%d, off=%#x, len=%#x", area->fa_id, off, len);
	flash_info = FLASH_DEV_NAME.GetInfo();

	if (flash_info->sector_info == NULL) {
	/* Uniform sector layout */
	while (deleted_len < len) {
	rc = FLASH_DEV_NAME.EraseSector(area->fa_off + off);
	if (rc != 0) {
	break;
	}
	deleted_len += flash_info->sector_size;
	off += flash_info->sector_size;
	}
	} else {
	/* Inhomogeneous sector layout, explicitly defined
	* Currently not supported.
	*/
	}

	return rc;
	}

	uint32_t flash_area_align(const struct flash_area *area)
	{
	ARM_FLASH_INFO *flash_info;

	flash_info = FLASH_DEV_NAME.GetInfo();
	return flash_info->program_unit;
	}

	/*
	* This depends on the mappings defined in sysflash.h, and assumes that the
	* primary slot, the secondary slot, and the scratch area are contiguous.
	*/
	int flash_area_id_from_image_slot(int slot)
	{
	#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];
	}

	return -EINVAL; /* flash_area_open will fail on that */
	}

	int flash_area_id_to_image_slot(int area_id)
	{
	if (area_id == FLASH_AREA_IMAGE_PRIMARY) {
	return 0;
	}
	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)
	{
	/*
	* This simple layout has uniform slots, so just fill in the
	* right one.
	*/

	switch (idx) {
	case FLASH_AREA_0_ID:
	*off = FLASH_AREA_0_OFFSET;
	*len = FLASH_AREA_0_SIZE;
	break;
	case FLASH_AREA_2_ID:
	*off = FLASH_AREA_2_OFFSET;
	*len = FLASH_AREA_2_SIZE;
	break;
	#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);
	return -1;
	}

	BOOT_LOG_DBG("area %d: offset=0x%x, length=0x%x, sector size=0x%x",
	idx, off, len, FLASH_AREA_IMAGE_SECTOR_SIZE);
	return 0;
	}

	int flash_area_to_sectors(int idx, int cnt, struct flash_area ret)
	{
	uint32_t off;
	uint32_t len;
	uint32_t max_cnt = *cnt;
	uint32_t rem_len;

	if (validate_idx(idx, &off, &len)) {
	return -1;
	}

	if (*cnt < 1) {
	return -1;
	}

	rem_len = len;
	*cnt = 0;
	while (rem_len > 0 && *cnt < max_cnt) {
	if (rem_len < FLASH_AREA_IMAGE_SECTOR_SIZE) {
	BOOT_LOG_ERR("area %d size 0x%x not divisible by sector size 0x%x",
	idx, len, FLASH_AREA_IMAGE_SECTOR_SIZE);
	return -1;
	}

	ret[*cnt].fa_id = idx;
	ret[*cnt].fa_device_id = 0;
	ret[*cnt].pad16 = 0;
	ret[cnt].fa_off = off + (FLASH_AREA_IMAGE_SECTOR_SIZE (*cnt));
	ret[*cnt].fa_size = FLASH_AREA_IMAGE_SECTOR_SIZE;
	cnt = cnt + 1;
	rem_len -= FLASH_AREA_IMAGE_SECTOR_SIZE;
	}

	if (*cnt > max_cnt) {
	BOOT_LOG_ERR("flash area %d sector count overflow", idx);
	return -1;
	}

	return 0;
	}

	/*
	* Lookup the sector map for a given flash area. This should fill in
	* `ret` with all of the sectors in the area. `*cnt` will be set to
	* the storage at `ret` and should be set to the final number of
	* sectors in this area.
	*/
	int flash_area_get_sectors(int idx, uint32_t cnt, struct flash_sector ret)
	{
	uint32_t off;
	uint32_t len;
	uint32_t max_cnt = *cnt;
	uint32_t rem_len;

	if (validate_idx(idx, &off, &len)) {
	return -1;
	}

	if (*cnt < 1) {
	return -1;
	}

	rem_len = len;
	*cnt = 0;
	while (rem_len > 0 && *cnt < max_cnt) {
	if (rem_len < FLASH_AREA_IMAGE_SECTOR_SIZE) {
	BOOT_LOG_ERR("area %d size 0x%x not divisible by sector size 0x%x",
	idx, len, FLASH_AREA_IMAGE_SECTOR_SIZE);
	return -1;
	}

	ret[cnt].fs_off = FLASH_AREA_IMAGE_SECTOR_SIZE (*cnt);
	ret[*cnt].fs_size = FLASH_AREA_IMAGE_SECTOR_SIZE;
	cnt = cnt + 1;
	rem_len -= FLASH_AREA_IMAGE_SECTOR_SIZE;
	}

	if (*cnt > max_cnt) {
	BOOT_LOG_ERR("flash area %d sector count overflow", idx);
	return -1;
	}

	return 0;
	}