Re: [Qemu-devel] qemu/hw pckbd.c

["Blue Swirl" <blauwirbel@gmail.com>]

On 4/18/07, Jocelyn Mayer <l_indien@magic.fr> wrote:
> On Wed, 2007-04-18 at 14:06 +0100, Thiemo Seufer wrote:
> > J. Mayer wrote:
> > > On Mon, 2007-04-16 at 22:47 +0000, Thiemo Seufer wrote:
> > > > CVSROOT:  /sources/qemu
> > > > Module name:      qemu
> > > > Changes by:       Thiemo Seufer <ths>     07/04/16 22:47:54
> > > >
> > > > Modified files:
> > > >   hw             : pckbd.c
> > > >
> > > > Log message:
> > > >   Support it_shift for mmapped pckbd.
> > > >
> > > > CVSWeb URLs:
> > > > http://cvs.savannah.gnu.org/viewcvs/qemu/hw/pckbd.c?cvsroot=qemu&r1=1.19&r2=1.20
> > >
> > > Thanks for the update.
> > > Here's another small patch, based on the same idea of what is done for
> > > the memory-mapped serial ports and which seems useful to implement some
> > > targets: it may be needed not to register the I/O memory area in the
> > > pckbd driver but let the caller do it.
> > > Please take a look.
> >
> > Actually, I thought about adding such a feature but then decided to
> > defer it until it is actually needed. OTOH, with qemu handling mmio
> > at page granularity it is likely needed sooner or later, so we could
> > just declare it a standard implementation feature. I am ok with it
> > either way.
>
> If you're interressed in such a feature, you may take a look of what
> I've done in hw/ppc405_uc.c. There are some device sharing the same
> memory page on those microcontrollers so I introduced a fake device
> called mmio that allow to register multiple devices into a single page
> in Qemu. I do use the serial_mm_init with the ioregister parameter set
> to 0 for those designs.
> This code may not be as generic as it would be if we want to make it a
> standard Qemu function, but this may give a basis or ideas for it.

On Sparc32 there are several devices that would benefit from sub-page
granularity, so I vote for making this generic.