Russell King writes:

Maybe this should've gone to linuxppc-dev?  Can PPC folk please look
at the PPC bits of this patch, and also decide whether the following
can also have asm/serial.h removed:

arch/ppc/4xx_io/serial_sicc.c
arch/ppc/boot/simple/mpc52xx_tty.c
arch/ppc/boot/simple/mv64x60_tty.c

The situation is that arch/ppc is the old world.  Platforms are being
moved over to arch/powerpc as fast as we can manage, where things will
be much cleaner because the information about type and location of
serial ports (among other things) will be supplied via a device tree
rather than hardcoded in header files.  This means, though, that there
isn't much motivation for cleaning up stuff in arch/ppc.

The two users in arch/ppc/boot aren't really part of the kernel
proper.  The compressed image bootwrapper uses definitions from
serial.h on some platforms to access a serial port for interaction
with the user.  It may be possible to replicate the string of #ifdefs
and #includes from serial.h in those files.  Tom Rini can best advise
about that.

The serial_sicc.c code looks like it should be converted to use the
serial_core stuff.  I hope that will get done in the process of moving
4xx over to arch/powerpc.

Paul.