Hello
I'm currently mounting a LittleFS partition in the internal flash of my Nordic MCU. However, since data is saved regularly to this partition, I’m concerned that the flash’s erase/write cycle limit could be reached in approximately 1.5 years, after which data integrity issues might occur.
To extend the product's lifespan, I’m considering moving this partition to RAM only.
Is this possible?
Environment :
- nrf52840
- nrf connect SDK : 2.9.0
Best regards,
Aurélien
Hello,
To extend the product's lifespan, I’m considering moving this partition to RAM only.
It should be possible, but definitely not recommended as you will lose all your data on a power surge or any other type of reset or power loss.
Instead, you can increase the LittleFS partition size. That will increase the sector count, which is one of the suggested measures to increase the life span in the documentation.
You can also consider using external flash instead of the internal flash on the nrf52840.
Hello
Thank you very much for your reply. I understand the implications of using RAM, but the main goal is to use LittleFS with the SMP Bluetooth service, which simplifies file exchange with a LittleFS partition mounted on the MCU.
In the end, I plan to use a mix of LittleFS partitions in flash (both internal and external) and in RAM, if possible. The external flash is already full.
Thank you for the link — I will check it out.
As for the LittleFS mounted in RAM, I’m facing some issues. There doesn't seem to be a proper example showing how to proceed.
Here is my code :
#define RAMDISK_SIZE (64 * 1024) // 64 KB
#define RAM_BLOCK_SIZE (4096)
static uint8_t ramdisk_buf[RAMDISK_SIZE];
// Définir le périphérique ramdisk (simplifié)
static struct fs_littlefs ramdisk_fs;
static struct fs_mount_t ramdisk_mount = {
.type = FS_LITTLEFS,
.mnt_point = "/RAMDISK",
.fs_data = &ramdisk_fs,
.storage_dev = NULL,
};
static int ramdisk_block_read(uint32_t block, uint32_t offset, void *buffer, uint32_t length) {
memcpy(buffer, &ramdisk_buf[block * RAM_BLOCK_SIZE + offset], length);
return 0;
}
static int ramdisk_block_write(uint32_t block, uint32_t offset, const void *buffer, uint32_t length) {
memcpy(&ramdisk_buf[block * RAM_BLOCK_SIZE + offset], buffer, length);
return 0;
}
static int ramdisk_block_erase(uint32_t block) {
memset(&ramdisk_buf[block * RAM_BLOCK_SIZE], 0xFF, RAM_BLOCK_SIZE);
return 0;
}
static int ramdisk_sync(const struct lfs_config *cfg) {
return 0; // Pas de sync nécessaire pour RAM
}
// Configuration LittleFS pour utiliser ces fonctions
struct lfs_config ramdisk_lfs_config = {
.read = ramdisk_block_read,
.prog = ramdisk_block_write,
.erase = ramdisk_block_erase,
.sync = ramdisk_sync,
.block_size = RAM_BLOCK_SIZE,
.block_count = RAMDISK_SIZE / RAM_BLOCK_SIZE,
.cache_size = RAM_BLOCK_SIZE,
.lookahead_size = 16,
.block_cycles = 500,
};
static struct fs_mount_t *mountpoint = &ramdisk_mount;
int int_ram_fs_init(void) {
int rc = 1;
struct fs_statvfs sbuf;
LOG_PRINTK("####################################\n");
LOG_PRINTK("Mount LITTLEFS on internal ram ...\n");
ramdisk_fs.lfs.cfg = &ramdisk_lfs_config;
/*
* Mount and erase if necessary
*/
rc = littlefs_mount(mountpoint);
if (rc < 0) {
littlefs_flash_erase((uintptr_t)mountpoint->storage_dev);
rc = littlefs_mount(mountpoint);
if (rc < 0) {
return rc;
}
}
m_int_flash_mounted = true;
}
output :
#################################### Mount LITTLEFS on internal ram ... I: LittleFS version 2.9, disk version 2.1 I: FS at mx25r1635f@0:0x0 is 512 0x1000-byte blocks with 512 cycle I: sizes: rd 16 ; pr 16 ; ca 64 ; la 32 /RAMDISK mount: 0 /RAMDISK: bsize = 16 ; frsize = 4096 ; blocks = 512 ; bfree = 510
The issue I'm facing is that each time I try to mount the partition that's supposed to be in RAM, it's the external one that gets mounted instead...
app.overlay :
/*
* Copyright (c) 2023 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
/*/delete-node/ &mx25r64;*/
/* /delete-node/ &storage_partition;*/
/*
&qspi {
status = "disabled";
};
*/
/ {
chosen {
nordic,pm-ext-flash = &mx25r16;
};
fstab {
compatible = "zephyr,fstab";
lfs1: lfs1 {
compatible = "zephyr,fstab,littlefs";
mount-point = "/lfs1";
partition = <&lfs1_partition>;
/*automount;*/
read-size = <16>;
prog-size = <16>;
cache-size = <64>;
lookahead-size = <32>;
block-cycles = <512>;
};
lfs2: lfs2 {
compatible = "zephyr,fstab,littlefs";
mount-point = "/lfs2";
partition = <&lfs2_partition>;
/*automount;*/
read-size = <16>;
prog-size = <16>;
cache-size = <64>;
lookahead-size = <32>;
block-cycles = <512>;
};
};
};
/*
&lfs1 {
status = "disabled";
};*/
/*
/ {
ram_disk0: ramdisk@20030000 {
compatible = "zephyr,ram-disk";
disk-name = "RAM";
sector-size = <512>;
sector-count = <128>; // 64 KB total
reg = <0x20030000 DT_SIZE_K(64)>;
};
};
*/
&flash0 {
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
boot_partition: partition@0 {
label = "mcuboot";
reg = <0x00000000 DT_SIZE_K(48)>;
};
slot0_partition: partition@c000 {
label = "image-0";
reg = <0x0000c000 DT_SIZE_K(432)>;
};
slot1_partition: partition@78000 {
label = "image-1";
reg = <0x00078000 DT_SIZE_K(432)>;
};
lfs2_partition: partition@E4000 {
label = "lfs2";
reg = <0x000E4000 DT_SIZE_K(104)>;
};
storage_partition: partition@fe000 {
label = "storage";
reg = <0x000fe000 DT_SIZE_K(2)>;
};
};
};
&uart1 {
status = "okay";
current-speed = <9600>;
pinctrl-0 = <&uart1_default>;
pinctrl-1 = <&uart1_sleep>;
pinctrl-names = "default", "sleep";
modbus0 {
compatible = "zephyr,modbus-serial";
status = "okay";
};
};
&spi2 {
compatible = "nordic,nrf-spi";
status = "okay";
cs-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
pinctrl-0 = <&spi2_default>;
pinctrl-1 = <&spi2_sleep>;
pinctrl-names = "default", "sleep";
mx25r16: mx25r1635f@0 {
compatible = "jedec,spi-nor";
reg = <0>;
spi-max-frequency = <8000000>;
jedec-id = [c2 28 15];
/*
sfdp-bfp = [
e5 20 f1 ff ff ff ff 03 44 eb 08 6b 08 3b 04 bb
ee ff ff ff ff ff 00 ff ff ff 00 ff 0c 20 0f 52
10 d8 00 ff 23 72 f5 00 82 ed 04 cc 44 83 68 44
30 b0 30 b0 f7 c4 d5 5c 00 be 29 ff f0 d0 ff ff
];*/
size = <DT_SIZE_M(16)>;
has-dpd;
t-enter-dpd = <10000>;
t-exit-dpd = <35000>;
};
};
&mx25r16 {
status = "okay";
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
lfs1_partition: partition@0 {
label = "lfs1";
reg = <0x00000000 0x200000>;
};
};
};
prj.conf :
# # Copyright 2024 # # All rights reserved # CONFIG_NCS_SAMPLES_DEFAULTS=y CONFIG_DK_LIBRARY=y CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048 CONFIG_USE_SEGGER_RTT=y CONFIG_RTT_CONSOLE=y CONFIG_UART_CONSOLE=n CONFIG_NEWLIB_LIBC=y CONFIG_NEWLIB_LIBC_FLOAT_PRINTF=y CONFIG_BT=y CONFIG_BT_PERIPHERAL=y CONFIG_BT_DEVICE_NAME="FREEDOM" CONFIG_BT_MAX_CONN=2 CONFIG_BT_SMP=y CONFIG_BT_MAX_PAIRED=8 CONFIG_BT_GATT_AUTO_SEC_REQ=y CONFIG_BT_FIXED_PASSKEY=y CONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y # Enable bonding CONFIG_BT_SETTINGS=y CONFIG_FLASH=y CONFIG_FLASH_PAGE_LAYOUT=y CONFIG_FLASH_MAP=y CONFIG_NVS=y CONFIG_SETTINGS=y CONFIG_SETTINGS_RUNTIME=y CONFIG_SETTINGS_NVS=y CONFIG_BT_DIS=y CONFIG_BT_DIS_SETTINGS=y CONFIG_BT_DIS_STR_MAX=32 CONFIG_BT_DIS_PNP=n CONFIG_BT_DIS_MODEL="FREEDOM" CONFIG_BT_DIS_MANUF="TELEDYNE" CONFIG_BT_DIS_SERIAL_NUMBER=y CONFIG_BT_DIS_FW_REV=y CONFIG_BT_DIS_HW_REV=y CONFIG_BT_DIS_SW_REV=y CONFIG_BT_DIS_SERIAL_NUMBER_STR="123456789abcdef" CONFIG_BT_DIS_FW_REV_STR="0.0.0" CONFIG_BT_DIS_HW_REV_STR="0.0.0" CONFIG_BT_DIS_SW_REV_STR="0.0.0" #Enable MCUBOOT bootloader build in the application CONFIG_BOOTLOADER_MCUBOOT=y CONFIG_MCUBOOT_SIGNATURE_KEY_FILE="priv.pem" #Include MCUMGR and the dependencies in the build CONFIG_NCS_SAMPLE_MCUMGR_BT_OTA_DFU=y #CONFIG_MCUMGR_TRANSPORT_BT_AUTHEN=y CONFIG_BT_EXT_ADV=y CONFIG_BT_EXT_ADV_MAX_ADV_SET=2 CONFIG_BT_DEVICE_NAME_DYNAMIC=n CONFIG_BT_CTLR_ADV_DATA_LEN_MAX=100 CONFIG_MODBUS=y #CONFIG_MODBUS_RAW_ADU=y #CONFIG_MODBUS_ROLE_CLIENT=y CONFIG_PARTITION_MANAGER_ENABLED=y CONFIG_FILE_SYSTEM=y CONFIG_FILE_SYSTEM_LITTLEFS=y CONFIG_CLOCK_CONTROL_NRF_K32SRC_RC=y CONFIG_CLOCK_CONTROL_NRF_K32SRC_XTAL=n CONFIG_MULTITHREADING=y CONFIG_HEAP_MEM_POOL_SIZE=60000 # Enable binary descriptors #CONFIG_BINDESC=y # Enable definition of binary descriptors #CONFIG_BINDESC_DEFINE=y # Enable default build time binary descriptors #CONFIG_BINDESC_DEFINE_BUILD_TIME=y #CONFIG_BINDESC_BUILD_DATE_TIME_STRING=y ################################################## ################ CONF TO CHECK ################### ################ TO BE REMOVED ################### ################################################## # Enable file system commands CONFIG_MCUMGR_GRP_FS=y CONFIG_MCUMGR_GRP_FS_DL_CHUNK_SIZE=200 # Enable the storage erase command. CONFIG_MCUMGR_GRP_ZBASIC=y CONFIG_MCUMGR_GRP_ZBASIC_STORAGE_ERASE=y # Optionally force the file system to be recreated #CONFIG_APP_WIPE_STORAGE=y # fs_dirent structures are big. CONFIG_MAIN_STACK_SIZE=4096 CONFIG_BT_RX_STACK_SIZE=4096 CONFIG_BT_HCI_TX_STACK_SIZE=4096 CONFIG_MCUMGR_TRANSPORT_WORKQUEUE_STACK_SIZE=6000 # Let __ASSERT do its job CONFIG_DEBUG=y CONFIG_INIT_STACKS=y CONFIG_THREAD_STACK_INFO=y CONFIG_STACK_SENTINEL=y CONFIG_THREAD_MONITOR=y CONFIG_THREAD_NAME=y CONFIG_PM_SINGLE_IMAGE=y # ou CONFIG_PM_MULTI_IMAGE si tu utilises MCUboot CONFIG_PM_OVERRIDE_EXTERNAL_DRIVER_CHECK=y CONFIG_PM_PARTITION_REGION_LITTLEFS_EXTERNAL=y #CONFIG_PM_PARTITION_REGION_SETTINGS_STORAGE_EXTERNAL=y #CONFIG_PM_PARTITION_REGION_NVS_STORAGE_EXTERNAL=y CONFIG_SPI=y CONFIG_SPI_NOR=y CONFIG_SPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096 #CONFIG_NORDIC_QSPI_NOR=y #CONFIG_NORDIC_QSPI_NOR_FLASH_LAYOUT_PAGE_SIZE=4096 CONFIG_GPIO=y CONFIG_NFCT_PINS_AS_GPIOS=y #CONFIG_LOG_DEFAULT_LEVEL=4 #CONFIG_WATCHDOG=n CONFIG_SERIAL=y CONFIG_UART_ASYNC_API=y CONFIG_UART_INTERRUPT_DRIVEN=n
pm_static.yml :
app:
address: 0xc200
end_address: 0x85000
region: flash_primary
size: 0x78e00
mcuboot:
address: 0x0
end_address: 0xc000
placement:
align:
end: 0x1000
before:
- mcuboot_primary
region: flash_primary
size: 0xc000
mcuboot_pad:
address: 0xc000
end_address: 0xc200
placement:
align:
start: 0x1000
before:
- mcuboot_primary_app
region: flash_primary
size: 0x200
mcuboot_primary:
address: 0xc000
end_address: 0x78000
orig_span: &id001
- mcuboot_pad
- app
region: flash_primary
sharers: 0x1
size: 0x6C000
span: *id001
mcuboot_primary_app:
address: 0xc200
end_address: 0x78000
orig_span: &id002
- app
region: flash_primary
size: 0x6Ce00
span: *id002
mcuboot_secondary:
address: 0x78000
end_address: 0xE4000
placement:
after:
- mcuboot_primary
align:
start: 0x1000
region: flash_primary
share_size:
- mcuboot_primary
size: 0x6C000
lfs2_partition:
address: 0xE4000
end_address: 0xFE000
placement:
align:
start: 0x1000
before:
- end
region: flash_primary
size: 0x1A000
settings_storage:
address: 0xfe000
end_address: 0x100000
placement:
align:
start: 0x1000
before:
- end
region: flash_primary
size: 0x2000
sram_primary:
address: 0x20000000
end_address: 0x20040000
region: sram_primary
size: 0x40000
littlefs_storage:
address: 0x0
size: 0x200000
device: mx25r16
end_address: 0x200000
region: external_flash
#external_flash:
# address: 0x0
# size: 0x200000
# device: mx25r16f
# region: external_flash
Understood. I have not done this before using RAM as a backend, but I will try to test this and report back to you.
Aurele said:The issue I'm facing is that each time I try to mount the partition that's supposed to be in RAM, it's the external one that gets mounted instead...
Btw, since you have littlefs partitions in both RAM and flash, maybe they get mixed up some how. Have you tried this without having a littlefs partition in flash at all? I haven't looked close at your code so I'm not sure why this is happening.
Yes, I tried without success. Now, I'm trying to configure a RAM disk in the app.overlay and then mount the partition, but that hasn't worked either :
app.overlay :
/*
* Copyright (c) 2023 Nordic Semiconductor ASA
*
* SPDX-License-Identifier: Apache-2.0
*/
/*/delete-node/ &mx25r64;*/
/* /delete-node/ &storage_partition;*/
/*
&qspi {
status = "disabled";
};
*/
/ {
chosen {
nordic,pm-ext-flash = &mx25r16;
};
fstab {
compatible = "zephyr,fstab";
lfs1: lfs1 {
compatible = "zephyr,fstab,littlefs";
mount-point = "/lfs1";
partition = <&lfs1_partition>;
/*automount;*/
read-size = <16>;
prog-size = <16>;
cache-size = <64>;
lookahead-size = <32>;
block-cycles = <512>;
};
lfs2: lfs2 {
compatible = "zephyr,fstab,littlefs";
mount-point = "/lfs2";
partition = <&lfs2_partition>;
/*automount;*/
read-size = <16>;
prog-size = <16>;
cache-size = <64>;
lookahead-size = <32>;
block-cycles = <512>;
};
};
// Partition en RAM (fictive via RAM-disk)
/*
ram_disk0: ramdisk@20030000 {
compatible = "zephyr,ram-disk";
disk-name = "RAM";
sector-size = <512>;
sector-count = <128>; // 64 KB total
reg = <0x20030000 DT_SIZE_K(64)>;
};*/
ramdisk0: ramdisk {
compatible = "zephyr,ram-disk";
disk-name = "RAM"; // ← doit correspondre exactement à storage_dev
sector-size = <512>;
sector-count = <128>; // ← 64 Ko
};
};
/*
&lfs1 {
status = "disabled";
};*/
/*
/ {
ram_disk0: ramdisk@20030000 {
compatible = "zephyr,ram-disk";
disk-name = "RAM";
sector-size = <512>;
sector-count = <128>; // 64 KB total
reg = <0x20030000 DT_SIZE_K(64)>;
};
};
*/
&flash0 {
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
boot_partition: partition@0 {
label = "mcuboot";
reg = <0x00000000 DT_SIZE_K(48)>;
};
slot0_partition: partition@c000 {
label = "image-0";
reg = <0x0000c000 DT_SIZE_K(432)>;
};
slot1_partition: partition@78000 {
label = "image-1";
reg = <0x00078000 DT_SIZE_K(432)>;
};
lfs2_partition: partition@E4000 {
label = "lfs2";
reg = <0x000E4000 DT_SIZE_K(104)>;
};
storage_partition: partition@fe000 {
label = "storage";
reg = <0x000fe000 DT_SIZE_K(2)>;
};
};
};
&uart1 {
status = "okay";
current-speed = <9600>;
pinctrl-0 = <&uart1_default>;
pinctrl-1 = <&uart1_sleep>;
pinctrl-names = "default", "sleep";
modbus0 {
compatible = "zephyr,modbus-serial";
status = "okay";
};
};
&spi2 {
compatible = "nordic,nrf-spi";
status = "okay";
cs-gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
pinctrl-0 = <&spi2_default>;
pinctrl-1 = <&spi2_sleep>;
pinctrl-names = "default", "sleep";
mx25r16: mx25r1635f@0 {
compatible = "jedec,spi-nor";
reg = <0>;
spi-max-frequency = <8000000>;
jedec-id = [c2 28 15];
/*
sfdp-bfp = [
e5 20 f1 ff ff ff ff 03 44 eb 08 6b 08 3b 04 bb
ee ff ff ff ff ff 00 ff ff ff 00 ff 0c 20 0f 52
10 d8 00 ff 23 72 f5 00 82 ed 04 cc 44 83 68 44
30 b0 30 b0 f7 c4 d5 5c 00 be 29 ff f0 d0 ff ff
];*/
size = <DT_SIZE_M(16)>;
has-dpd;
t-enter-dpd = <10000>;
t-exit-dpd = <35000>;
};
};
&mx25r16 {
status = "okay";
partitions {
compatible = "fixed-partitions";
#address-cells = <1>;
#size-cells = <1>;
lfs1_partition: partition@0 {
label = "lfs1";
reg = <0x00000000 0x200000>;
};
};
};
my code :
static struct fs_littlefs lfs_data_ram;
static struct fs_mount_t lfs_ram_mnt = {
.type = FS_LITTLEFS,
.mnt_point = "/lfs/ram",
.fs_data = &lfs_data_ram,
.storage_dev = "RAM",
};
static struct fs_mount_t *mountpoint = &lfs_ram_mnt;
int int_ram_fs_init(void) {
int rc = 1;
struct fs_statvfs sbuf;
LOG_INF("Mounting LittleFS on RAM...");
disk_access_init("RAM");
if (DISK_STATUS_OK != disk_access_status("RAM")) {
LOG_PRINTK("RAM disk not ready");
} else {
LOG_PRINTK("RAM disk is ready");
}
LOG_PRINTK("####################################\n");
LOG_PRINTK("Mount LITTLEFS on internal ram ...\n");
//ramdisk_fs.lfs.cfg = &ramdisk_lfs_config;
/*
* Mount and erase if necessary
*/
rc = littlefs_mount(mountpoint);
if (rc < 0) {
littlefs_flash_erase((uintptr_t)mountpoint->storage_dev);
rc = littlefs_mount(mountpoint);
}
return rc
}
The output :
I: Mounting LittleFS on RAM... RAM disk is ready #################################### Mount LITTLEFS on internal ram ... I: LittleFS version 2.9, disk version 2.1 E: can't open flash area 329300 E: fs mount error (-19) FAIL: mount id 329300 at /lfs/ram: -19 E: FAIL: unable to find flash area 329300: -2