Wrong read from settings_storage flash in nRF52840 and nRF Connect SDK 2.4.1

Question

Hi, 
 I have an example based on v2.4.1
rf\samples\bluetooth\peripheral_lbs 
 This is my prj.conf 
 # Flash
CONFIG_FLASH=y
CONFIG_FLASH_MAP=y
CONFIG_FLASH_PAGE_LAYOUT=y
CONFIG_MPU_ALLOW_FLASH_WRITE=y

# Bluetooth
CONFIG_BT=y
CONFIG_BT_PERIPHERAL=y
CONFIG_BT_DEVICE_NAME="Intonavi"

# FOTA
CONFIG_BOOTLOADER_MCUBOOT=y
CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU=y
CONFIG_SECURE_BOOT=y
CONFIG_SB_SIGNING_KEY_FILE="d:/NordicSemiconductor/apps/ble_ota2/priv-ecdsa.pem" 
 this is my pm_static.yml, this is copy from file: build/partitions.yml 
 EMPTY_0:
 address: 0x15200
 end_address: 0x16000
 placement:
 before:
 - s1_pad
 region: flash_primary
 size: 0xe00
EMPTY_1:
 address: 0x22200
 end_address: 0x23000
 placement:
 before:
 - mcuboot_pad
 region: flash_primary
 size: 0xe00
EMPTY_2:
 address: 0xf5000
 end_address: 0xf6000
 placement:
 after:
 - mcuboot_secondary
 region: flash_primary
 size: 0x1000
app:
 address: 0x23200
 end_address: 0x8c000
 region: flash_primary
 size: 0x68e00
app_image:
 address: 0x23200
 end_address: 0x8c000
 orig_span: &id001
 - app
 region: flash_primary
 size: 0x68e00
 span: *id001
b0:
 address: 0x0
 end_address: 0x8000
 placement:
 after:
 - start
 region: flash_primary
 size: 0x8000
b0_container:
 address: 0x0
 end_address: 0x9000
 orig_span: &id002
 - b0
 - provision
 region: flash_primary
 size: 0x9000
 span: *id002
mcuboot:
 address: 0x9200
 end_address: 0x15200
 placement:
 before:
 - mcuboot_primary
 region: flash_primary
 sharers: 0x1
 size: 0xc000
mcuboot_pad:
 address: 0x23000
 end_address: 0x23200
 placement:
 align:
 start: 0x1000
 before:
 - mcuboot_primary_app
 region: flash_primary
 sharers: 0x2
 size: 0x200
mcuboot_primary:
 address: 0x23000
 end_address: 0x8c000
 orig_span: &id003
 - mcuboot_pad
 - app
 region: flash_primary
 sharers: 0x1
 size: 0x69000
 span: *id003
mcuboot_primary_app:
 address: 0x23200
 end_address: 0x8c000
 orig_span: &id004
 - app
 region: flash_primary
 size: 0x68e00
 span: *id004
mcuboot_secondary:
 address: 0x8c000
 end_address: 0xf5000
 placement:
 after:
 - mcuboot_primary
 align:
 start: 0x1000
 region: flash_primary
 share_size:
 - mcuboot_primary
 size: 0x69000
provision:
 address: 0x8000
 end_address: 0x9000
 placement:
 after:
 - b0
 align:
 start: 0x1000
 region: flash_primary
 size: 0x1000
s0:
 address: 0x9000
 end_address: 0x15200
 orig_span: &id005
 - s0_pad
 - mcuboot
 region: flash_primary
 size: 0xc200
 span: *id005
s0_image:
 address: 0x9200
 end_address: 0x15200
 orig_span: &id006
 - mcuboot
 region: flash_primary
 size: 0xc000
 span: *id006
s0_pad:
 address: 0x9000
 end_address: 0x9200
 placement:
 after:
 - b0_container
 align:
 start: 0x1000
 region: flash_primary
 share_size:
 - mcuboot_pad
 size: 0x200
s1:
 address: 0x16000
 end_address: 0x22200
 orig_span: &id007
 - s1_pad
 - s1_image
 region: flash_primary
 size: 0xc200
 span: *id007
s1_image:
 address: 0x16200
 end_address: 0x22200
 placement:
 after:
 - s1_pad
 - s0
 region: flash_primary
 share_size:
 - mcuboot
 size: 0xc000
s1_pad:
 address: 0x16000
 end_address: 0x16200
 placement:
 after:
 - s0
 align:
 start: 0x1000
 region: flash_primary
 share_size:
 - mcuboot_pad
 size: 0x200
settings_storage:
 address: 0xf6000
 end_address: 0xf8000
 placement:
 align:
 start: 0x1000
 region: flash_primary
 size: 0x2000
sram_primary:
 address: 0x20000000
 end_address: 0x20040000
 region: sram_primary
 size: 0x40000
storage_partition:
 address: 0xf8000
 end_address: 0x100000
 region: flash_primary
 size: 0x8000 
 I init parametres for settings_storage of flash 
 #define DATA_PARTITION_OFFSET FIXED_PARTITION_OFFSET (settings_storage)
#define DATA_PARTITION_DEVICE FIXED_PARTITION_DEVICE (settings_storage) 
 
 Now i do the following: 
 Build, Flash, with flash_erease, flash_write and flash_read. This is my console log 
 Flash is ready Test 1: Flash erase page at 0xf6000 Flash erase succeeded! Attempted to write 12c at 0xf6000 Data read: 12c | 300, at 0xf6000 Attempted to write 64 at 0xf6004 Data read: 64 | 100, at 0xf6004 Attempted to write 1 at 0xf6008 Data read: 1 | 1, at 0xf6008 Attempted to write 2 at 0xf600c Data read: 2 | 2, at 0xf600c 
 Next step. Comment flash_erease and flash_ write, only flash_ read is active. Build and Flash device. This is my console log 
 Flash is ready Data read: b8397b06 | -1204192506, at 0xf6000 Data read: 689acd9a | 1754975642, at 0xf6004 Data read: 615433a5 | 1632908197, at 0xf6008 Data read: 4293d3ff | 1116984319, at 0xf600c 
 Why values are different? 
 When I use storage_partition and hard address 0xf8000 everyfing is ok, after write all next reads have corrected values.

Hieu · Accepted Answer

Hi Tomasz, 
 The way the partition manager is setup, depends on Kconfig, it will give the such auto-generated partitions, like the settings_partition , the storage_partition and storage "aliases" in flash_map_pm.h . This is because certain modules and subsystems in the Zephyr RTOS are built requiring partitions with such name. 
 One such subsystem is Settings . It is used to store all of the persistent data that many subsystems and modules need. The Settings subsystem by default uses the partition named storage . In your case, due to the aliasing, it would use the settings_storage partition. 
 That is most likely why your data is overwritten. 
 If you want to share the settings_storage partition with the Settings subsystem, you need to store your data outside of the region the Settings subsystem use. Here is a DevZone case where I explained about that: Zephyr NVS on an nRF5340_DK . 
 Regarding your partition named storage_partition , did you create it yourself for some purpose? I tried to build a Peripheral LBS with your prj.conf file. The partition.yml file generated does not have such a partition. I recommend you avoid this name, as it collides with the name of the commonly used partition I mentioned above. 
 Hieu

Wrong read from settings_storage flash in nRF52840 and nRF Connect SDK 2.4.1

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