smh Use ARM semihosting calls for early console.
+ s3c2410,<addr>
+ s3c2412,<addr>
+ s3c2440,<addr>
+ s3c6400,<addr>
+ s5pv210,<addr>
+ exynos4210,<addr>
+ Use early console provided by serial driver available
+ on Samsung SoCs, requires selecting proper type and
+ a correct base address of the selected UART port. The
+ serial port must already be setup and configured.
+ Options are not yet supported.
+
earlyprintk= [X86,SH,BLACKFIN,ARM,M68k]
earlyprintk=vga
earlyprintk=efi