Edge2 boot sequence

Edge2 have advanced and flexible boot possibilities

Common boot process

SPL-loader ⇒ U-Boot-loader ⇒ OOWOW-special-mode ⇒ U-Boot-OS-boot-sequence ⇒ OOWOW-rescue-mode

SPL loader

SPL-loader is a 1st boot-loader which can start from SPI-Flash ⇒ eMMC ⇒ SD card. By default its start from SPI-flash.
SPL-loader scan special areas for next U-Boot-loader by SD ⇒ eMMC ⇒ SPI-FLash

common logs

U-Boot SPL board init
U-Boot SPL 2017.09 (Aug 26 2022 - 15:50:37)
MCU: bootmode: 1, oowow 0
board_boot_order: /chosen found, using spl_boot_device()
!!! same-as-spl: 
!!! /mmc@fe2c0000: 
!!! /mmc@fe2e0000: 
!!! /spi@fe2b0000/flash@1: 
Trying to boot from MMC2 :: 0
Card did not respond to voltage select!
Trying to boot from MMC1 :: 1
Trying fit image at 0x4000 sector
Not fit magic
Trying fit image at 0x5000 sector
Not fit magic
Trying to boot from MTD2 :: 2
Trying fit image at 0x300 sector
...

oowow-mode logs

log spl-boot-oowow-mode-example.log

U-Boot SPL board init
U-Boot SPL 2017.09 (Aug 26 2022 - 15:50:37)
MCU: bootmode: 1, oowow 1
MCU: oowow 2
board_boot_order: /chosen found, using spl_boot_device()
!!! same-as-spl: 
+++ /spi@fe2b0000/flash@1: 
!!! /mmc@fe2c0000: 
!!! /mmc@fe2e0000: 
!!! /spi@fe2b0000/flash@1: 
Trying to boot from MTD2 :: 0
Trying fit image at 0x300 sector
...
Jumping to U-Boot(0x00200000) via ARM Trusted Firmware(0x00040000)
...

U-Boot loader

U-Boot OS boot sequence

We discribe only about SPI-flash u-boot, for other custom U-boots which can stored at eMMC or SD its will be different

OS booting follow by distro_bootcmd which use boot_targets priority for scanning bootable OS. Step by step scan all available storage's and partitions for os-boot-configuration-extlinux-config

kedge2# printenv boot_targets 
boot_targets=usb0 mmc1 mmc0 pxe dhcp fail

OS boot configuration - extlinux config

Basic example:

extlinux/extlinux.conf

menu background /logo.bmp
LABEL Default
  LINUX /Image
  INITRD /initrd.img
  FDTDIR /dtb
  APPEND ${bootargs} earlycon=uart8250,mmio32,0xfeb50000 console=ttyFIQ0 console=tty0 irqchip.gicv3_pseudo_nmi=0 root=LABEL=ROOTFS rootflags=data=writeback rw rootfstype=ext4
timeout  10
default Default

OOWOW mode

OOWOW mode can be activated by

special on board short-cuts FUNCTION + RESET
under running OS via special MCU-register-for-start-oowow - software way

OOWOW special mode

OOWOW rescue mode

MCU register for start oowow

Khadas Docs

Sidebar

Table of Contents

Edge2 boot sequence

Common boot process

SPL loader

common logs

oowow-mode logs

U-Boot loader

U-Boot OS boot sequence

OS boot configuration - extlinux config

OOWOW mode

OOWOW special mode

OOWOW rescue mode

MCU register for start oowow

Khadas Docs

User Tools

Site Tools

Sidebar

Table of Contents

Edge2 boot sequence

Common boot process

SPL loader

common logs

oowow-mode logs

U-Boot loader

U-Boot OS boot sequence

OS boot configuration - extlinux config

OOWOW mode

OOWOW special mode

OOWOW rescue mode

MCU register for start oowow

Page Tools