Re: [PATCH 1/2] tty: serial: Fix build on architecture that does not have ioport

From: Arnd Bergmann
Date: Fri Mar 11 2011 - 02:58:46 EST


On Friday 11 March 2011 06:54:56 Nobuhiro Iwamatsu wrote:
> Some CPU's do not have ioport. Therefore, these do not have inX/outX.
> Because they define CONFIG_NO_IOPORT, These CPU's use this and do not
> use inX/outX.
>
> Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@xxxxxxxxxxx>

I like this patch, I had played with something similar before
but never got it to the state where I was happy with submitting
it. I'd really like to get us to the point where platforms without
PCI support do don't need to define inb/outb and can still
use all other drivers.

There are two small improvements that I would like to suggest
to this patch:

* use #ifdef CONFIG_SERIAL_8250_HUB6 to configure out hub6 support.
It's already disabled on most systems, so we can save a bit
binary code without making the driver uglier.

* Introduce a new CONFIG_SERIAL_8250_IOPORT symbol and make
the normal io_serial_* code depend on that. It can be a silent
Kconfig symbol that automatically gets selected in the appropriate
cases. I find this clearer than the double negation in "not no ioport".
The code that is used in both HUB6 and regular cases can be under
this symbol.

Arnd
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