SBL Booting Linux From SD CARD

Introduction

  • SBL booting Linux from eMMC (see EXAMPLES_DRIVERS_SBL_EMMC_LINUX_MULTISTAGE) is a secondary bootloader application that boots Linux on A53 core and RTOS/NORTOS application on R5 core.

  • The bootloader makes use of 4 appimages

    • A Linux appimage containing the Linux binaries (ATF, OPTEE, A53 SPL).

    • tiboot3.bin with SBL SD, TIFS, BoardConfig

    • Appimage for MCU R5

    • Appimage for WKUP R5

  • The Linux appimage can be generated by using Linux Appimage Generator Tool

  • The appimages will be copied to SD card, the SBL parses the appimages from the boot partition, loads and run the cores.

Bootflow for SBL booting linux from SD Card

  • The bootflow for SBL booting Linux is as follows

    Bootflow for SBL booting Linux

SD Card Partitioning

  • SD card uses two partitions to boot Linux

    • A boot partition

      • tiboot3.bin

      • mcu_r5_image

      • wkup_r5_image

      • linux_a53_image

    • A ext4 partition in the user data area containing

      • Linux Kernel image

      • Linux DTB

      • Linux file system

See Also