I have an imx8mm based system. I'm using Yocto dunfell with meta-freescale providing kernel 5.4.107.
I am trying to simplify the kernel command line, and remove kernel-specific parameters that would better be specified in the device tree. The main items are (a) console; (b) earlycon; and (c) root. It would be better if these were defined in the device tree, rather than in U-Boot environment variables which are not so easily changed with a kernel upgrade.
Currently the kernel command line for my board includes
and that works. But it would be better if the console were defined in the device tree.
The device tree specifies the console in node chosen/stdout-path. I had it set to
stdout-path = &uart3;
But that doesn't work (when console=... is removed from kernel command line). After reading the docs, I changed it to:
stdout-path = "serial2:115200n8";
That also doesn't work. Looking at /proc/consoles, the console gets set to ttymxc0 instead of ttymxc2.
I found these, but they are not recent, and I haven't worked out if they're still relevant: