[U-Boot-Users] Any default audio card driver in U-boot?

Martin Krause Martin.Krause at tqs.de
Wed Nov 16 08:56:44 CET 2005

Hi Boku,

boku wrote on Wednesday, November 16, 2005 8:26 AM:
> Dear Martin,
>     Thanks for the information to me. I'd like to ask you further
> about your audio driver. Did you design the driver based on ALSA
> architecture? Or you directly write your driver without it? I met some
> problems while using alsa to build my audio driver for a specific arm
> soc chip. Thanks in advance.

No, we didn't base on ALSA. We only needed a quick hack to test
our audio hardware. For linux audio driver the usage of DMA is a must,
to feed the audio codec continuously with data (any interruption in
the audio stream would be hearable).
Since U-Boot is single-tasking, instead of DMA transfers, a polling
mechanism could be used to feed the audio codec continously with data.
This is much easier to implement - and is the way we did it.

Regards, Martin

> On 8/22/05, Martin Krause <Martin.Krause at tqs.de> wrote:
> > Hi,
> > 
> > u-boot-users-admin at lists.sourceforge.net wrote on Monday, August 22,
> > 2005 5:42 AM:
> > > Dear all,
> > >     I'm searching for some example for audio card driver for
> > > U-boot? But it seems most drivers in drivers/ are for ethernet
> > > card. Can anyone tell me where I can find it in u-boot? Thanks a
> > > lot!~ 
> > 
> > We implemented some _very_ basic sound commands (play a beep, play
> > square wave, play a microsoft .wav file) to test our hardware
> > with it. Perhaps you will find this usefull. Please look at:
> > 
> > http://source.denx.net/cgi-bin/gitweb.cgi?p=u-boot.git;a=commit;h=6617aae9b9f297c388fc011bdf4eb6c4553339e6
> > 
> > The commands are implemented in board/tqm5200/cmd_stk52xx.c

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