How to get debug info when working on u-boot support?

fourkbomb / u-boot

u-boot for galaxy s3/note 2. no longer eats (many) cats.

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How to get debug info when working on u-boot support? #1

Closed MYEUHD closed 4 years ago

MYEUHD commented 5 years ago

Hi, I'm interested in making aries (codename for 1st gen Galaxy S devices) work with u-boot as a PBL and SBL. You said in your blogpost about u-boot in the galaxy s3 that the second basic step was to: "Check that the BL2 works at least well enough to write stuff out to UART." I'm curious, is there a way to get debug info before reaching that state?

Thanks!

fourkbomb commented 5 years ago

Not easily... I had access to a vendor u-boot dump which had been adapted to boot on i9300 (https://github.com/dmarszk/exynos4_uboot/). My debugging method was basically to manually trace through the assembler and figure out what was being done differently.

I guess if you're writing u-boot to the sdcard you might be able to get it to write stuff to RAM somewhere and read it from the Samsung PBL/SBL when booting without the sdcard (That's just a thought - I don't really know how you'd do this)