AM62x MCU+ SDK  08.06.00
SBL Booting Linux From eMMC

Table of Contents

Introduction

  • The bootloader makes use of 6 appimages
    • A Linux appimage containing the Linux binaries (ATF, OPTEE, A53 SPL).
    • tiboot3.bin with SBL stage1, TIFS, BoardConfig
    • Appimage for SBL stage2
    • Appimage for MCU M4
    • Appimage for HSM M4
    • DM firmware appimage for DM R5
  • The Linux appimage can be generated by using Linux Appimage Generator Tool
  • The appimages will be flashed to the offset on eMMC specified by SysCfg, the SBL parses the appimages from these locations, loads and run the cores.

Features Supported

  • Boots R5, M4 cores and Linux on A53 from eMMC.
  • SBL booting Linux can be used when early booting of R5 and M4 cores are required. When using uBoot to run R5 and M4 cores the application will start running on R5, M4 cores only after booting Linux

Features NOT Supported

  • SBL booting Linux supports only booting from OSPI (see SBL OSPI Linux Multistage) and eMMC.
  • If SD card or other boot modes are required, user might need to switch to booting Linux using Linux uBoot.

Bootflow for SBL booting linux from eMMC

Note
The binaries for R5, M4 cores need not be in the linux file system (root/lib/firmware), when SBL is booting Linux.
  • The bootflow for SBL booting Linux is as follows

Bootflow for SBL booting Linux

EMMC Partitioning

Note
The default SD card image for AM62x-evm can be used to boot Linux using SBL
The tiboot3.bin, tispl.bin will not be used for booting Linux when using SBL booting Linux.
The R5 binaries in the root partition (eg : root/lib/firmware/am62-main-r5f0_0-fw) will not be used when SBL boots Linux and R5,M4 cores.
  • eMMC uses two patitions to boot Linux
    • A boot patition
      • tiboot3.bin
      • tispl.bin
      • u-boot.img
      • uboot.env
    • A ext4 partition in the user data area containing
      • Linux Kernel image
      • Linux DTB
      • Linux file system

See Also