April 25, 2017

Hacking U-Boot -- the DTB and DTS scheme

If you spend some time roaming around the U-Boot sources, you start wondering just where all the hardware addresses are. The place to start looking is in arch/arm/dts. This directory holds a vast collection of "dts" files, one for each board that U-Boot supports in this way.

In my case I am working with an Orange Pi. This has the "sun8i" architecture and in particular has an Allwinner H3 chip. With this knowledge you can restrict your attention to the 19 files that begin with "sun8i-h3" and this quickly leads you to: 

sun8i-h3-orangepi-pc-plus.dts
sun8i-h3-orangepi-pc.dts
sun8i-h3.dtsi
The "dtb" files are binary "blobs" compiled from the "dts" source files. As you might imagine, the "plus" is derived from the plain "pc" and the "sun8i-h3.dtsi" file is common information for the whole gang of H3 based boards.

Have any comments? Questions? Drop me a line!

Tom's electronics pages / tom@mmto.org