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# Common features of system components and BSP framework

This chapter provides lists of features which are provided by certain system components for the default BSP configuration.

## System components

### Trusted bootloader

For STM32MP1 platform these features are provided

- Secure monitor based on 'arm-trusted-firmware'
- Booting from SD card
- Booting from QSPI flash
- Locking OTP values on write

Supported by SOC and platform, but not in BSP:

- Secure application
- Secure boot

### U-boot bootloader

For STM32MP1 platform an u-boot bootloader is provided

- U-boot environment is located in NOR flash
- Redundant u-boot environment
- U-boot environment auto detection (sd card, nor) dependent on boot device
- Auto flashing of u-boot environment with default boot command if environment is empty
- Support for USB storage interfaces
- Support for NOR and NAND Flashes of SOM via MTD framework
- Support for eMMC flash and SD cards on baseboard
- Support for UBI based flash storage
- Support for file access on ext4 and fat32 filesystems
- Support for SOC Ethernet interface
- Support for booting from network
- Basic network commands: tftp, ping, dhcp
- Support for AB double copy boot scheme
- Can boot extlinux non-double copy images and AB scheme double copy images

Supported by SOC platform, but not in BSP:

- Display interface
- Loading M4 program

### Linux kernel

For STM32MP1 platform the following Kernel features are provided:

- Linux kernel version 5.10 or higher
- IPv4 stack
- Filesystems ext4, fat, fat32
- MTD flash framework
- UBI flash framework
- SD card and eMMC storage framework
- Wireless Ethernet stack

## Firmware Images

Firmware images provide adapted solutions for certain use cases.

### Basic image (image-ktn)

Use case: Basic linux system without graphics support

For all platforms the basic image `image-ktn` provides:

- SysV init system
- Hardware watchdog
- SwUpdate OTA update framework
- ifup/ifdown for Network configuration
- wpa-supplicant for wireless connectivity
- udevd for dynamic device generation
- dbus daemon
- udhcpc dhcp client
- Openssh ssh server
- zeroconf upnp ethernet configuration
- can tools

Supported by SOC platform, but not in BSP:

- Power save and deep sleep modes
- Secure boot

### SWUpdate AB double copy image (image-ktn-swu)

Use case: Demo image to show the integration of SWUpdate embedded software update framework

This images provides all features of `image-ktn` and additionally the SWUpdate framework for embedded devices on top of a double copy AB boot scheme. It provides support for updating the current boot device (SD card, eMMC, NAND) and provides a demo web interface to update the software of the device.

For more information about SWUpdate see https://sbabic.github.io/swupdate/

## Yocto BSP build infrastructure

Features provided for all machines

- Script to initialize build environment and to fetch sources from web
- Creating a bootable SD card
- Building bootloaders
- Building images