SmartFS is a file system used for user partitions in TizenRT. This document provides details on SmartFS in TizenRT, notably on its architecture, and how to enable it on a new target board.
- About SmartFS
- SmartFS Code Layering
- How to Enable SmartFS on New Board
- How to make SmartFS user image
SmartFS stands for Sector Mapped Allocation for Really Tiny (SMART) flash.
It is a file system that has been designed to work primary with small and
serial NOR type flash parts that are 1M byte to 16M byte in size
(though this is not a limitation).
The file system operates by segmenting the flash (or flash partition) into “logical sectors” of equal size and then managing them (allocating, mapping, chaining, releasing, etc.) to build files and directories.
This guide explains the steps and details for enabling SmartFS on a new board.
SmartFS consists of two layers built on top of a standard MTD Driver.
Below diagram shows code layers regarding the two SmartFS layers.
+----------------------------------------------+
| Smart FS (Smart File System Layer) |
+----------------------------------------------+
| Smart MTD Driver (Smart Block Driver Layer) |
+----------------------------------------------+
| MTD Driver (MTD Block Driver Layer) |
+----------------------------------------------+
| FLASH Driver (Flash Driver) |
+----------------------------------------------+
The code directly above the MTD Driver is the SMART MTD layer.
This interfaces with the MTD (flash driver) layer and handles low-level
media operations such as logical sector allocation, freeing and management,
erase block management, low-level formatting, wear leveling, etc.
On top of the SMART MTD layer is the Smart File System Layer.
The SmartFS code uses the logical sector services of the SMART MTD layer to
provide file and directory level management, such as creating new files,
chaining logical sectors together to create files, and creating directories/files
with management routines.
- add FLASH Driver for the flash present in the SoC/Board.
- enable MTD Driver corresponding to flash.
- enable SMART MTD Driver.
- enable SMART FS.
Flash driver must provide low-level read/write/erase capability for the FLASH HW.
Example of flash driver is present at os/arch/arm/src/s5j/s5j_sflash.c
During bootup flash driver must be initialized similar to the following example.
/* In case of s5j */
void arm_boot(void)
{
...
s5j_board_initialize();
...
}
void s5j_board_initialize(void)
{
#ifdef CONFIG_S5J_SFLASH
s5j_sflash_init();
#endif
}/* In case of imxrt */
void __start(void)
{
...
/* Initialize onboard resources */
imxrt_boardinitialize();
...
}
void imxrt_boardinitialize(void)
{
...
imxrt_flash_init();
}MTD Driver must be enabled to access the underlying FLASH driver.
The MTD driver initialization, however, varies by target board.
Below configurations must be enabled to use MTD Driver.
- Enable CONFIG_MTD
File Systems -> Memory Technology Device (MTD) Support = y - Enable CONFIG_MTD_PARTITION
File Systems -> Memory Technology Device (MTD) Support -> Support MTD partitions = y - Enable CONFIG_MTD_PARTITION_NAMES
File Systems -> Memory Technology Device (MTD) Support -> Support MTD partition naming = y
Refer to os/board/common/partitions.c for example of MTD driver initialization.
#ifdef CONFIG_MTD_PROGMEM
mtd = progmem_initialize();
if (!mtd) {
lldbg("ERROR: progmem_initialize failed\n");
return;
}
if (mtd->ioctl(mtd, MTDIOC_GEOMETRY, (unsigned long)&geo) < 0) {
lldbg("ERROR: mtd->ioctl failed\n");
return;
}
#else
mtd = up_flashinitialize();
if (!mtd) {
lldbg("ERROR : up_flashinitializ failed\n");
return;
}
if (mtd->ioctl(mtd, MTDIOC_GEOMETRY, (unsigned long)&geo) < 0) {
lldbg("ERROR: mtd->ioctl failed\n");
return;
}
#endifFor the board such as s5j that supports progmem operations (refer os/fs/driver/mtd/mtd_progmem.c),
CONFIG_MTD_PROGMEM should be enabled first.
File Systems -> Memory Technology Device (MTD) Support -> Enable on-chip program FLASH MTD device = y
For the board such as imxrt, CONFIG_MTD_PROGMEM is disabled and up_flashinitialize needs to be implemented. (refer os/arch/arm/src/imxrt/imxrt_norflash.c)
Smart MTD layer can be enabled via the CONFIG_MTD_SMART config parameter.
File Systems -> Memory Technology Device (MTD) Support -> Sector Mapped Allocation for Really Tiny (SMART) Flash support = y
Refer os/fs/driver/mtd/smart.c for smart MTD driver code.
And a smart device can be initialized as shown below. (Refer os/board/common/partitions.c)
#ifdef CONFIG_MTD_CONFIG
if (!strncmp(types, "config,", 7)) {
mtdconfig_register(mtd_part);
} else
#endif
#if defined(CONFIG_MTD_SMART) && defined(CONFIG_FS_SMARTFS)
if (!strncmp(types, "smartfs,", 8)) {
char partref[4];
snprintf(partref, sizeof(partref), "p%d", partno);
smart_initialize(CONFIG_FLASH_MINOR, mtd_part, partref);
} else
#endif
{
}The above code snippet creates a smart device node similar to /dev/smart0p[partno].
Smart FS layer can be enabled by enabling below configurations.
- Enable CONFIG_FS_SMARTFS
File Systems -> SMART file system = y - Set CONFIG_SMARTFS_ERASEDSTATE
File Systems -> SMART file system -> SMARTFS options -> FLASH erased state = 0xff - Set CONFIG_SMARTFS_MAXNAMLEN=32
File Systems -> SMART file system -> SMARTFS options -> Maximum file name length = 32 - Enable CONFIG_SMARTFS_ALIGNED_ACCESS
File Systems -> SMART file system -> SMARTFS options -> Ensure 16 and 32 bit accesses are aligned = y
Below are the optional features configurations. Refer os/fs/smartfs/Kconfig for more details.
- CONFIG_SMARTFS_MULTI_ROOT_DIRS
File Systems -> SMART file system -> SMARTFS options -> Support multiple Root Directories/Mount points - CONFIG_SMARTFS_DYNAMIC_HEADER
File Systems -> SMART file system -> SMARTFS options -> Dynamic Header - CONFIG_SMARTFS_JOURNALING
File Systems -> SMART file system -> SMARTFS options -> Enable filesystem journaling for smartfs - CONFIG_SMARTFS_SECTOR_RECOVERY
File Systems -> SMART file system -> SMARTFS options -> Enable recovery of lost sectors in Filesystem
SmartFS filesystem can be mounted on smart mtd device.
Before mounting, smart device needs to formatted as smartfs using a mksmartfs function.
Sample code for formatting and mounting SmartFS:
#ifdef CONFIG_ARTIK05X_AUTOMOUNT_USERFS
/* Initialize and mount user partition (if we have) */
ret = mksmartfs(ARTIK05X_AUTOMOUNT_USERFS_DEVNAME, false);
if (ret != OK) {
lldbg("ERROR: mksmartfs on %s failed\n",
ARTIK05X_AUTOMOUNT_USERFS_DEVNAME);
} else {
ret = mount(ARTIK05X_AUTOMOUNT_USERFS_DEVNAME,
CONFIG_ARTIK05X_AUTOMOUNT_USERFS_MOUNTPOINT,
"smartfs", 0, NULL);
if (ret != OK) {
lldbg("ERROR: mounting '%s' failed\n",
ARTIK05X_AUTOMOUNT_USERFS_DEVNAME);
}
}
#endif /* CONFIG_ARTIK05X_AUTOMOUNT_USERFS */
Smart FS can also be mounted in TASH Shell as shown below:
- Format the partition using mksmartfs command
Usage : mksmartfs <device name> Example : mksmartfs /dev/smart0p8 - Mount smartfs using mount command
Usage : mount -t <fs-type> <source/device name> <target/ logical mount path> Example : mount -t smartfs /dev/smart0p8 /mnt
TizenRT provides the way of making SmartFS user image with user content. It is possible to program into the filesystem partition.
Please find the details in How to make SmartFS user image.