On Tue, 23 Aug 2022 01:15:01 +0200, Pali Rohár wrote:

Currently powerpc early debugging contains lot of platform specific
options, but does not support standard UART / serial 16550 console.

Later legacy_serial.c code supports registering UART as early debug console
from device tree but it is not early during booting, but rather later after
machine description code finishes.

[...]

Applied to powerpc/next.

[1/1] powerpc: Add support for early debugging via Serial 16550 console
      https://git.kernel.org/powerpc/c/b19448fe846baad689ff51a991ebfc74b4b5e0a8

cheers