[Sound-open-firmware] Status of ssp driver in Qemu

[Liam Girdwood]

On Fri, 2019-12-20 at 11:34 +0200, Daniel Baluta wrote:
> On Fri, Dec 20, 2019 at 11:31 AM Liam Girdwood
> <liam.r.girdwood at linux.intel.com> wrote:
> > 
> > On Wed, 2019-12-18 at 21:24 +0000, Daniel Baluta wrote:
> > > Hi Liam,
> > > 
> > > I wonder what is the status of the SSP driver in Qemu.
> > > Particularly,
> > > I'm interested
> > > about ssp->tx.fd / ssp->rx.fd.
> > > 
> > > It looks like these files are only opened and closed but never
> > > written to / read from.
> > > 
> > > Can you explain what is your idea on emulating the DAIs on Qemu?
> > 
> > The intention is to be able to perform file IO for SSP IO. i.e. SSP
> > playback would write to a file and SSP capture would read from a
> > file.
> > This worked in a early version prior to upstreaming, but it was a
> > hack
> > that needed cleaning up (still TODO).
> > 
> > Using file IO for DAI emulation means we can script and more easily
> > validate input/output data from any processing.
> 
> Thanks! Do you still have the patches? The upstream version doesn't
> do
> and read/write now and I was confused about what's the purpose of
> just opening the files :).

Sadly they were on my dead NUC. 

IIRC, it was mostly just file IO. Fwiw, we started moving some of the
file IO to DMA virt driver (i.e. write evey playback block to file as
this meant we did not need to virtualise the DAIs, just the DMA) and we
could also see the data before and after the pipeline.

Liam