AM6422: How to modify and build the kernel DTS file in Yocto's TI SDK

Kalyan Agepati

Part Number: AM6422

Tool/software:

Hi TI Support Team,

I am trying to build a custom root filesystem using Yocto's TI SDK version sdk-kirkstone-09.02.01.10.

To modify, I need to know the location of the Device Tree Source (DTS) files within the Yocto TI SDK 9 build system, as well as the command needed to build the modified DTS file using Yocto.

FYI, I have tried with the "bitbake -c compile virtual/kernel " command, but I did not find the latest .dtb file.

Regards, Kalyan

7 months ago

0 Andreas Dannenberg 7 months ago

TI__Guru 69977 points

I'm currently out of the office and will look at your request after my return next week. In the meantime I'd encourage you to search existing E2E threads, the topic of configuring the Kernel in Yocto has come up a few times already.

Regards, Andreas

0 Kalyan Agepati 7 months ago in reply to Andreas Dannenberg

Prodigy 220 points

Hi Andreas,

I have tried to modify the .dts files(k3-am642-evm.dts) in the listed path. But I still have not found the latest .dtb file generated with the changes at tisdk/build/deploy-ti/images/am64xx-evm.

Please let me know the working command needed to build the modified DTS file using Yocto.

tisdk/build/arago-tmp-default-glibc/work/am64xx_evm-oe-linux/linux-ti-staging/6.1.83+gitAUTOINC+c1c2f1971f-r0b.arago5_tisdk_3_edgeai_0_edgeai_8/srcipk-staging/board-support/ti-linux-kernel-6.1.83+gitAUTOINC+c1c2f1971f-ti/arch/arm64/boot/dts/ti

regards, Kalyan

0 Andreas Dannenberg 7 months ago in reply to Kalyan Agepati

TI__Guru 69977 points

Kalyan Agepati said:
FYI, I have tried with the "bitbake -c compile virtual/kernel " command, but I did not find the latest .dtb file.

You'll need to force-compile the Kernel package for the changes to get picked up, either using `-C compile`, or `-f -c compile` command line options.

Since you'll need to make the changes to your device tree permanent eventually perhaps it's easier you just use the following approach:

1) Create a patch that makes the changes you need to your DTS file

2) Integrate the patch into Yocto by adding a custom layer. This E2E post here has steps how to do that for both Kernel and U-Boot: https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1303384/sk-am62-using-custom-kernel-in-local-workspace-for-yocto-ti-sdk/4953153#4953153

Regards, Andreas

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AM6422: How to modify and build the kernel DTS file in Yocto's TI SDK