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
console=ttymxc2,115200 earlycon=ec_imx6q,0x30880000,115200
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:
