uart_parse_earlycon — Parse earlycon options
| int uart_parse_earlycon ( | char * p, | 
| unsigned char * iotype, | |
| unsigned long * addr, | |
| char ** options ); | 
pptr to 2nd field (ie., just beyond '<name>,')
iotypeptr for decoded iotype (out)
addrptr for decoded mapbase/iobase (out)
optionsptr for <options> field; NULL if not present (out)
Decodes earlycon kernel command line parameters of the form earlycon=<name>,io|mmio|mmio32|mmio32be|mmio32native,<addr>,<options> console=<name>,io|mmio|mmio32|mmio32be|mmio32native,<addr>,<options>
   The optional form
   earlycon=<name>,0x<addr>,<options>
   console=<name>,0x<addr>,<options>
   is also accepted; the returned iotype will be UPIO_MEM.
   
Returns 0 on success or -EINVAL on failure