Configfs

Applicable for

STM32MP13x lines, STM32MP15x lines

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1 Introduction

Configfs is a RAM-based filesystem that provides the converse of sysfs functionality.

While sysfs provides a filesystem-based view of kernel objects, configfs is a filesystem-based manager of kernel objects or config_items (every object in configfs is a config_item). This means that kernel objects can be created, managed and destroyed from the user space.

2 Installing configs on your target board

Configfs can be enabled and ready to be used in all STM32MPU Embedded Software distribution, via the Linux^® kernel configuration CONFIG_CONFIGFS_FS (set to yes by default):

Symbol: CONFIGFS_FS
Location:
  File systems --->
    Pseudo filesystems -->
      -*- Userspace-driven configuration filesystem

Please refer to Menuconfig or how to configure kernel article for instructions for modifying the configuration and recompiling the Linux kernel image in the Distribution Package context.

3 Getting started

3.1 How to mount configfs

Use the following command to mount Configfs at /sys/kernel/config:

 mount -t configfs none /sys/kernel/config

3.2 How to set and manage configfs from Linux kernel drivers and user space

Refer to the Linux documentation for detailed information.

Configfs is used by the USB framwework. Refer to USB API description for an example.

Random access memory (Early computer memories generally hadserial access. Memories where any given address can be accessed when desired were then called "random access" to distinguish them from the memories where contents can only be accessed in a fixed order. The term is used today for volatile random-acces ssemiconductor memories.)

System file system (see https://en.wikipedia.org/wiki/Sysfs for more details)

Configuration file system (see https://en.wikipedia.org/wiki/Configfs for more details)

Linux^® is a registered trademark of Linus Torvalds.

File system or filesystem, method and data structure that the operating system uses to control how data is stored and retrieved -NEW

Random access memory (Early computer memories generally hadserial access. Memories where any given address can be accessed when desired were then called "random access" to distinguish them from the memories where contents can only be accessed in a fixed order. The term is used today for volatile random-acces ssemiconductor memories.)

System file system (see https://en.wikipedia.org/wiki/Sysfs for more details)

Configuration file system (see https://en.wikipedia.org/wiki/Configfs for more details)

Linux^® is a registered trademark of Linus Torvalds.

File system or filesystem, method and data structure that the operating system uses to control how data is stored and retrieved -NEW