About Ubuntu booting sequence

Which system do you use? Android, Ubuntu, OOWOW or others?

Ubuntu 22.04

Which version of system do you use? Khadas official images, self built images, or others?

Official image

Please describe your issue below:

Frankly speaking, I’m a beginner at embedded world. ^^;;
I’d like to know the booting sequence of Ubuntu linux on VIM4 so I captured the booting log at my VIM4 and the log below is the first part of the booting log.
I know the Uboot is bootloader.
However the log below was output before the Uboot.
What’s the BL2/BL2E/BL2X… ?
And the initialization of LPDDR4 is not do in uboot but do in BL2 ?
Then where can I find the source code of BL2…?
I’d like to see the source code.

Post a console log of your issue below:


Bl2_early_platform_setup: indicates bl2ex flow!

OTP_LIC00 : 0f0300000000ff1f2f000b0000000000
OTP_LIC10 : 008207000001fc000c00001000000300
OTP_LIC20 : ffffffbfffff0700ff80008003000003
OTP_LIC30 : 00000002010000008f03000203000000

TE: 303354

BL2 Built : 17:12:14, May  5 2022. t7 origin/master gcad8fc9 - jenkins@walle02-sh

Board ID = 5
Set sys clock to 24Mhz
syspll is 1512Mhz. Locked
sys1pll is 1608Mhz. Locked
Set sys clock to 167Mhz
gp0pll is 0Mhz. Locked
boot area list: 
1STBLOB	00000200	00040000
BL2E	00040200	00013000
BL2X	00053200	00011000
DDRFIP	00064200	00040000
DEVFIP	000a4200	00300000
s_setup from rom:00010081
dma mode
derive RSPK OK
DDR driver_vesion: AML_S_PHY_T7_1_16 build time: May  5 2022 17:12:08
ddr id: 0

ddr clk to 2016MHz
PIEI done
Cfg max: 2, cur: 1. Board id: 255. Force loop cfg

LPDDR4 probe

ddr clk to 2016MHz
Check phy result
INFO : End of CA training
INFO : End of initialization
INFO : Training has run successfully!
Check phy result

AFAIK, BL2 = uboot.
I’m not an expert too, but somehow Google suggested this article : Embedded Linux boot process | loliot
And, if you prefer Korean 한국어가 편하시다면 :slight_smile: think of me :: 2. 임베디드 리눅스 시작은 Bootloader!!!말고 구조 파악부터!

Thank you. 감사합니다. 알려주신 사이트 잘 보고 공부하도록 하겠습니다. ^^