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Table of Contents
Edge2 Boot flow
Edge2 have advanced and flexible boot flow … see also Edge2 boot sequence
MCU ⇒ BROM ⇒ SPL ⇒ U-Boot ⇒ OS target
Next information actual for MCU ver: 0x0002
Hardware buttons
POWER+RESET- force boot from SD/eMMC.FUNCTIONx3 times - flash mode
More detail: hardware-buttons
MCU features
See too: mcu-registers-annotation
Boot mode
Common boot mode configuration 0x20
| boot mode | value |
|---|---|
| spi | 0 |
| mmc | 1 |
- boot-mode read
i2cget -f -y 2 0x18 0x20
Boot flag
This flag 0x92 will be used one time on next reboot!
| boot flag | value |
|---|---|
| disabled | 0 |
| OOWOW request | 1 |
| boot from SPI | 2 |
| boot from eMMC | 3 |
- boot-flag read
i2cget -f -y 2 0x18 0x92
Reboot mode
We can reboot device by non standard way via MCU 0x91 register with special options.
| reboot mode | value |
|---|---|
| SPI | 0 |
| normal reboot | 1 |
| eMMC | 2 |
- reboot-mode read
i2cset -f -y 2 0x18 0x91 value
Device will be rebooted immediately after successful writing to 0x91 MCU register
Only normal reboot == 1 dos not change boot-flag on next reboot!
SPI == 0 will change boot-flag to 2 on next reboot
eMMC == 2 will change boot-flag to 3 on next reboot
See too: mcu-registers-annotation
Boot modes oowow shell usage
Boot mode setup examples
## read current boot-mode ~# bootmode spi ## setup to MMC ~# bootmode mmc [i] /opt/bootmode spi -> mmc(sd) ~# bootmode mmc ## setup to SPI ~# bootmode spi [i] /opt/bootmode mmc -> spi
Set oowow mode
~# mcu_oowow_mode set 1 [i] set with 1 ~# mcu_oowow_mode clean [i] set with 0 ~# mcu_oowow_mode && echo activated 0x01 activated ~# mcu_oowow_mode clean [i] set with 0 ~# mcu_oowow_mode || echo disabled disabled ~# i2cset -f -y 2 0x18 0x92 1 ~# i2cget -f -y 2 0x18 0x92 0x01
Reboot by MCU examples
Forced hardware reboot
## oowow shell ~# mcu_reboot ## common system ~# i2cset -f -y 2 0x18 0x91 1
Reboot into OOWOW via i2c command
- reboot into oowow
i2cset -f -y 2 0x18 0x92 1 i2cset -f -y 2 0x18 0x91 1
Reboot from SPI flash U-Boot via i2c command
not works as need
- reboot into oowow
i2cset -f -y 2 0x18 0x92 0 i2cset -f -y 2 0x18 0x91 0
SPL stage
SPL boot loader priority: spi ⇒ emmc ⇒ sd - hard-coded by MCU and BROM
SPL boot loader priority not same as mcu bootmode. MCU boot mode works only after SPL boot stage passed.
Boot mode mmc logs:
U-Boot stage
Current u-boot can start OS from USB ⇒ SD ⇒ eMMC ⇒ …
oowow spi uboot
- boot_targets
kedge2# printenv boot_targets boot_targets=usb0 mmc1 mmc0 pxe dhcp fail
mmc uboot
default eMMC u-boot log for Ubuntu images
- boot_targets
kedge2# printenv boot_targets boot_targets=usb0 mmc1 mmc0 pxe dhcp
Advanced
MCU registers annotation
MCU version: 02 & 03
0x91 REBOOT_MODE
0 - reset and boot from SPI
1 - reset normal
2 - reset and boot from eMMC
0x92 BOOT_FLAG
0 - normal
1 - press FUNC boot-up
2 - reset from SPI boot-up
3 - reset from eMMC boot-up
See too: mcu-features
U-boot spl
SPI Flash partitions table
- MTD parts
0x000000000000-0x000000080000 : "bootloader" # 0x03f800 bytes x 2 > 0x000000 0x040000 < 0 0x000000080000-0x0000000a6000 : "bl2e" # 0x013000 bytes x 2 > 0x080000 0x093000 < 0x00040000 0x0000000a6000-0x0000000c8000 : "bl2x" # 0x011000 bytes x 2 > 0x0a6000 0x0b7000 < 0x00053000 0x0000000c8000-0x000000148000 : "ddrfip" # 0x040000 bytes x 2 > 0x0c8000 0x108000 < 0x00064000 0x000000148000-0x000000448000 : "devfip" # 0x275000 bytes > 0x148000 < 0x000a4000 0x000000448000-0x000000488000 : "env" # zero 0x000000488000-0x0000004c8000 : "dtb" # zero 0x0000004c8000-0x0000006c8000 : "boot" # zero 0x0000006c8000-0x000002000000 : "user" # zero