Kernel bootargs

flatmax · December 29, 2020, 2:35am

I’ve got a very simple uboot working here :

It is missing the correct bootargs for the kernel. Does anyone know a good set of bootargs ?
I was thinking of this :

setenv bootargs “root=/dev/mmcblk1 earlyprintk=serial,uart0,115200 rw rootwait”

However it is missing the correct console parameter. Once the kernel boots, the console is no longer output on uart0. Any suggestions for the correct addition to the bootargs line to get the console working ?

thanks
Matt

Stephen · January 2, 2021, 12:31pm

You can add this argument. And enable UART0 in device tree file.

console=ttyS0,115200n8

flatmax · January 4, 2021, 1:43am

Got it thanks.

I ended up using the following bootargs :
setenv bootargs “root=/dev/mmcblk0p2 earlyprintk console=ttyS0,115200n8 rw rootwait”

From here :

github.com

flatmax/buildroot.rk3308/blob/master/board/RK3308/boot.cmd

setenv bootargs "root=/dev/mmcblk0p2 earlyprintk console=ttyS0,115200n8 rw rootwait"
fatload mmc ${devnum}:${distro_bootpart} ${fdt_addr_r} ${fdtfile}
fatload mmc ${devnum}:${distro_bootpart} ${kernel_addr_r} Image
booti ${kernel_addr_r} - ${fdt_addr_r}