pcm sound driver for SBus Ultra1/Ultra2

[Scott Long]

Pyun YongHyeon wrote:
> Hello All,
> 
> I don't know how may users want to hear sound on Ultra1/Ultra2.
> But I wanted to hear some music while 'build world' is in progress.
> 
> <Driver summary>
>  1. The driver is based on OpenBSD's driver and ISA mss driver
>     on FreeBSD.
>  2. Supports onboard CS4231A chip on SBus Ultra1/Ultra2.
>  3. Capture(recodring) was not tested at all.
>       - I don't have microphone.
>  4. Due to lack of programming information for APC DMA, I
>     used existing interfaces of OpenBSD driver. So it may have
>     some bugs on FreeBSD.
>  5. Full-duplex mode doesn't work.
>  6. You may notice some noise when you work on ofw console. I don't
>     know what is the reason, atm.
>  7. Due to lack of X supports, I could't test with xmms or GUI based
>     audio tools.
>  8. If you have PCI/EBus based sparcs, they are not supported. Yes, they
>     use the same chip but have different DMA interface. In addition, I
>     don't have PCI/EBus based sparcs.
> 
> Installation
>  1. get the driver patch file and fetch your system
>  2. build kernel and kernel modules
>  3. load snd_cs4231.ko and play
>      Note, you may want to mute speaker output with mixer(8).
> 
> The attached patch is for -CURRENT, and is also available at:
>  http://www.kr.freebsd.org/~yongari/cs4231.freebsd.diff
> 
> Corrections, suggestions welcome.
> Thanks.
> 
> Regards,
> Pyun YongHyeon
> 

Once again, you've done another impressive job =-)  The biggest question
that I have is why you chose to base the work on the mss driver and not
the cs428x driver.  I looked at this briefly a few weeks ago and
decided (after also looking at NetBSD) that it really only needed to be
abstracted so it could take both a PCI and an SBUS front-end.  The only
thing that held me back was the lack of busdma support.

Since this requires stubs into sndbuf_dma.c it might not be totally
appropriate as it is, but I'd like to also review it further over the
next few days and get back to you.  Thanks!

Scott