ALSA Driver for ARM

ALSA Driver for ARM

[K.Fetscher]

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Hi,

I want to programm an driver for the Cirrus CS42516 and the ARM9 CPU 
EP93xx also from Cirrus.

I think, there are several errors:

- when I start aplay, I receive a buffer. A dump to this memory region 
show only zeros.

- after the complete buffer is transmitted (but not the complete file), 
I receive an underrun from ALSA

- I never detect a mmap function call.

I have attached the source code and also the Debug output.

Thanks

Klaus

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Re: ALSA Driver for ARM

[T-Online]

Hi,

I have a new hint, but the problem is not solved.

> I want to programm an driver for the Cirrus CS42516 and the ARM9 CPU 
> EP93xx also from Cirrus.
>
> I think, there are several errors:
>
> - when I start aplay, I receive a buffer. A dump to this memory region 
> show only zeros.
>
I have written some characters into the DMA Memory Area (with a Hardware 
Debugger) when the driver is started, but aplay is not started. After I 
start aplay, all my characters are overwritten with Zero.

Which function in ALSA is responsible for filling the DMA Buffer ?

> - after the complete buffer is transmitted (but not the complete 
> file), I receive an underrun from ALSA
>
> - I never detect a mmap function call.
>
>  

Thanks,

Klaus


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Re: ALSA Driver for ARM

[Nicolas Pitre]

On Mon, 28 Mar 2005 K.Fetscher@t-online.de wrote:

> Hi,
> 
> I want to programm an driver for the Cirrus CS42516 and the ARM9 CPU EP93xx
> also from Cirrus.

What kernel version are you using?


Nicolas


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Re: ALSA Driver for ARM

[K.Fetscher]

Nicolas Pitre schrieb:

>>I want to programm an driver for the Cirrus CS42516 and the ARM9 CPU EP93xx
>>also from Cirrus.
>>    
>>
>
>What kernel version are you using?
>
>  
>
I am using kernel 2.6.11.3-ep93xx

 http://linux-cirrus.bkbits.net


Klaus


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Re: ALSA Driver for ARM

[Takashi Iwai]

At Tue, 29 Mar 2005 23:31:08 +0200,
T-Online wrote:
> 
> Hi,
> 
> I have a new hint, but the problem is not solved.
> 
> > I want to programm an driver for the Cirrus CS42516 and the ARM9 CPU 
> > EP93xx also from Cirrus.
> >
> > I think, there are several errors:
> >
> > - when I start aplay, I receive a buffer. A dump to this memory region 
> > show only zeros.
> >
> I have written some characters into the DMA Memory Area (with a Hardware 
> Debugger) when the driver is started, but aplay is not started. After I 
> start aplay, all my characters are overwritten with Zero.
> 
> Which function in ALSA is responsible for filling the DMA Buffer ?

If it's not mmap mode, it must be through
SNDRV_PCM_IOCTL_WRITEI_FRAMES ioctl (note that alsa-lib doesn't use
write syscall).

i.e. snd_pcm_lib_write() -> snd_pcm_lib_writei() ->
  snd_pcm_lib_write_transfer() -> copy_from_user()


Takashi


> > - after the complete buffer is transmitted (but not the complete 
> > file), I receive an underrun from ALSA
> >
> > - I never detect a mmap function call.
> >
> >  
> 
> Thanks,
> 
> Klaus
> 
> 
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> _______________________________________________
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> 


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Re: ALSA Driver for ARM

[Nicolas Pitre]

On Wed, 30 Mar 2005 K.Fetscher@t-online.de wrote:

> Nicolas Pitre schrieb:
> 
> > > I want to programm an driver for the Cirrus CS42516 and the ARM9 CPU
> > > EP93xx
> > > also from Cirrus.
> > >    
> > 
> > What kernel version are you using?
> > 
> >  
> I am using kernel 2.6.11.3-ep93xx

If it's 2.6.11 or above then the problem is most likely to be in your 
own code.  Prior kernel versions had problems with the mapping of DMA 
memory.


Nicolas


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