[SOLVED] iMX8M Passing bootargs from U-Boot

I am trying to understand how the bootargs are being passed to the kernel from U-Boot.
Is there any fixed address the kernel looks at? or Is it stored in some RAM location and the address is passed onto kernel through "x" registers?

Board: Variscite DART iMX8M (A-53)

Thanks and Regards,
Bharat Kumar.

Originally Posted by bachabharat I am trying to understand how the bootargs are being passed to the kernel from U-Boot. ... Is there any fixed address the kernel looks at?

No.

Originally Posted by bachabharat or Is it stored in some RAM location and the address is passed onto kernel through "x" registers?

Almost.
The bootargs environment variable is used as the kernel command line, and for an ARM processor is inserted into either the legacy ATAGs list or the Device Tree blob.
The memory address of the ATAGs or dtb is passed to the ARM kernel in the r2 register.
Study Booting ARM Linux for full details.

Originally Posted by bachabharat I am not interested in using U-Boot prompt to setup environment variables.

Your negative statement is not clear as to what you do want to do.
Take a look at my answer here.
If you do not want U-Boot to provide a command line, you can either configure the kernel with a default command line, or install a command line in the Device Tree.

Regards

The bootargs environment variable is used as the kernel command line, and for an ARM processor is inserted into either the legacy ATAGs list or the Device Tree blob.

This worked for me. Added a node(bootargs)in the device tree before passing the FDT address to the kernel in X0 register.

Thanks @blue_z.

Regards,
Bharat