Re: [Qemu-devel] [PATCH 1/4] Split serial-isa into its own config option

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jun 29, 2015 at 11:35:23AM +0100, Peter Maydell wrote:
> On 29 June 2015 at 06:36, David Gibson <david@gibson.dropbear.id.au> wrote:
> > At present, the core device model code for 8250-like serial ports
> > (serial.c) and the code for serial ports attached to ISA-style legacy IO
> > (serial-isa.c) are both controlled by the CONFIG_SERIAL variable.
> >
> > There are lots and lots of embedded platforms that have 8250-like serial
> > ports but have never had anything resembling ISA legacy IO.  Therefore,
> > split serial-isa into its own CONFIG_SERIAL_ISA option so it can be
> > disabled for platforms where it's not appropriate.
> >
> > For now, I enabled CONFIG_SERIAL_ISA in every default-config where
> > CONFIG_SERIAL is enabled, excepting microblaze, xtensa and or32.  Those
> > platforms have technically lost functionality, but since they have no
> > other PCI or ISA devices, it's fairly clear they never actually used
> > leagacy IO stuff.
> 
> s/leagacy/legacy/
> 
> Is it worth having a default-configs/isa.mak along the
> lines of our current pci.mak and usb.mak, for putting
> CONFIG_ defines for all ISA devices?

I considered it, but there were enough variations in exactly what ISA
options were selected in the existing configs for different targets
that it seemed like a substantial distraction from what I'm trying to
accomplish.

> A quick grep suggests you can knock arm, moxie, sh4
> and sh4eb off your list of things with CONFIG_SERIAL_ISA
> (no hits for ISABus).
> 
> I notice in passing that we still have a handful of config
> files which set CONFIG_ISA_MMIO, despite that having been
> deleted in commit 61fcb628627ea4 two years ago.
> 
> thanks
> -- PMM
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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