This article aims at presenting, as example, the directory structure of the Linux root file system available on STM32 board.
All files and directories are located under the root directory (/), in compliance with the File system Hierarchy Standard.
This root directory corresponds to the Linux root file system (rootfs partition), as defined in Flash partitions. Note also that the user file system (userfs partition), the boot file system (bootfs partition) and the vendor file system (vendorfs partition) can be accessed through the /usr/local mounting point, through the /boot mounting point, and through the /vendor mounting point respectively.
 Information
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| In practice, this article uses the release STM32MP15-Ecosystem-legacy for the STM32MPU Embedded Software distribution as an example to illustrate the Linux directory structure. If you are using a different release, the names of the directories and files might differ. |
The directories are shown in green, while the files are in black.
/ Root directory (rootfs partition) ├── bin Essential user binaries (e.g. /bin/cat, /bin/ls, /bin/cp...) │ └── [...] ├── boot Mounting point for the boot file system (bootfs partition): see below ├── dev Device files (e.g. /dev/null, /dev/tty0, /dev/video0...) ├── etc System-wide configuration files (e.g. /etc/xdg/weston/weston.ini Weston configuration file...) ├── home Users' home directories (containing saved files, personal settings...) ├── lib Essential system libraries for the binaries in /bin and /sbin (e.g. libncurses.so.*...) │ ├── modules │ │ └── 6.1.82 The directory name is the linux version (i.e. 6.1.82) │ │ ├── kernel Linux kernel modules │ │ │ └── [...] │ │ ├── modules.dep List of module dependencies (generated by depmod) │ │ └── [...] │ └── [...] ├── lost+found ├── media Mount points for removable media devices ├── mnt Temporarily mounted file systems ├── proc Pseudo filesystem providing process and kernel information as files (e.g. /proc/cpuinfo, /proc/version...) ├── root Home directory for the root user) ├── run Run-time variable data (information about the running system since last boot) ├── sbin Essential system binaries (e.g. /sbin/fsck, /sbin/init, /sbin/modprobe...) ├── sys Information about devices, drivers, and some kernel features (e.g. /sys/kernel/debug akadebgufs...) ├── tmp Temporary files ├── usr User utilities and applications │ ├── bin Non-essential user binaries (e.g. /usr/bin/lsusb, /usr/bin/weston...) │ ├── lib Non-essential system libraries for the binaries in /usr/bin and /usr/sbin │ ├── local Mounting point for the user file system (userfs partition): see below │ ├── sbin Non-essential system binaries (e.g. /usr/sbin/alsactl, /usr/sbin/weston.sh...) │ ├── share Architecture-independent (shared) data │ └── [...] ├── var Variable files └── vendor Mounting point for the vendor file system (vendorfs partition): see below
- Boot file system mounting point
/boot bootfs partition ├── stm32mp157f-dk2[*].dtb Linux kernel device tree blob files → STM32MP157F-DK2 ├── stm32mp157f-ev1[*].dtb Linux kernel device tree blob files → STM32MP157F-EV1 ├── [...] ├── uImage Linux kernel binary image file (with U-Boot wrapper) └── [...]
- User file system mounting point (Example based on STM32MP25x lines
)
/usr/local userfs partition ├── Cube-M4-examples Examples for STM32CubeMP1 Package running on Arm® Cortex®-M4 │ ├── STM32MP157F-DK2 Examples of firmwares running on Arm Cortex-M4 → STM32MP157F-DK2 (see more in STM32CubeMP15 Package) │ │ ├── Applications │ │ │ ├── OpenAMP │ │ | | ├── OpenAMP_TTY_echo OpenAMP TTY echo application │ │ │ | | ├── fw_cortex_m4.sh Script to start/stop this application │ │ │ | | ├── lib │ │ │ | | │ └── firmware │ │ │ | | │ └── OpenAMP_TTY_echo.elf Firmware for this application │ │ │ | | └── README Helper file for this application │ │ │ │ └── [...] Other OpenAMP applications with the same structure (script, helper file and firmware) │ │ │ └── [...] Other applications with the same structure (script, helper file and firmware) │ │ ├── Demonstrations │ │ │ ├── AI_Character_Recognition Artificial intelligence character recognition demonstration │ │ │ └── lib │ │ │ └── firmware │ │ │ └── AI_Character_Recognition.elf Firmware for this demonstration │ │ └── Examples │ │ ├── GPIO │ │ | └── GPIO_EXTI GPIO EXTI example │ │ | ├── fw_cortex_m4.sh Script to start/stop this example │ │ | ├── lib │ │ | │ └── firmware │ │ | │ └── GPIO_EXTI.elf Firmware for this example │ │ | └── README Helper file for this example │ │ └── [...] Other examples with the same structure (script, helper file and firmware)
│ └── STM32MP157F-EV1 Examples of firmwares running on Arm Cortex-M4 → STM32MP157F-EV1 (see more in STM32CubeMP15 Package) │ ├── Applications │ │ └── [...] Applications with the same structure (script, helper file and firmware) │ ├── Demonstrations │ │ └── [...] Demonstrations with the same structure (script, helper file and firmware) │ └── Examples │ └── [...] Examples with the same structure (script, helper file and firmware)
├── Linux-A7-examples Examples for Linux® running on Arm® Cortex®-A7 │ ├── GPIO GPIO examples │ │ ├── buttons │ │ │ ├── button_gpio_exti.sh Script for this example │ │ | └── README.md Helper file for this example │ │ └── leds Same structure for this example relative to the leds │ │ └── [...] │ └── [...] Same structure for all the examples ├── demo All files needed (e.g. Python scripts, pictures, media files...) for the GTK demo launcher │ └── [...] ├── lost+found └── weston-start-at-startup └── start_up_demo_launcher.sh Script to start the GTK demo launcher
- Vendor file system mounting point
/vendor vendorfs partition ├── [*].so Specific vendor libraries (e.g. Vivante libraries OpenGL ES, OpenVG and EGL) └── [...]
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere. 
Arm® is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.