earlycon= [KNL] Output early console device and options.
+ cdns,<addr>
+ Start an early, polled-mode console on a cadence serial
+ port at the specified address. The cadence serial port
+ must already be setup and configured. Options are not
+ yet supported.
+
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
uart[8250],mmio32,<addr>[,options]
must already be setup and configured. Options are not
yet supported.
+ msm_serial,<addr>
+ Start an early, polled-mode console on an msm serial
+ port at the specified address. The serial port
+ must already be setup and configured. Options are not
+ yet supported.
+
+ msm_serial_dm,<addr>
+ Start an early, polled-mode console on an msm serial
+ dm port at the specified address. The serial port
+ must already be setup and configured. Options are not
+ yet supported.
+
smh Use ARM semihosting calls for early console.
earlyprintk= [X86,SH,BLACKFIN,ARM,M68k]