Table of Contents
Edge2 boot sequence
Edge2 have advanced and flexible boot possibilities
Common boot process
SPL loader
- SPL-loader is a 1st boot-loader which can start from
SPI-Flash⇒eMMC⇒SDcard. By default its start fromSPI-flash.
common logs
- spl-boot-example.log
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