[alsa-devel] [PATCH 2/2] ALSA sound driver for the AT73C213 DAC using Atmel SSC driver
hcegtvedt at atmel.com
Tue Jul 17 10:54:19 CEST 2007
On Tue, 2007-07-17 at 10:48 +0200, Haavard Skinnemoen wrote:
> On Tue, 17 Jul 2007 10:37:21 +0200
> Hans-Christian Egtvedt <hcegtvedt at atmel.com> wrote:
> > > > + snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &at73c213_playback_ops);
> > > > +
> > > > + retval = snd_pcm_lib_preallocate_pages_for_all(chip->pcm,
> > > > + SNDRV_DMA_TYPE_DEV,
> > > > + snd_dma_continuous_data(GFP_KERNEL),
> > > > + 64 * 1024, 64 * 1024);
> > >
> > > For SNDRV_DMA_TYPE_DEV, pass the struct device pointer of the device
> > > to the third argument. Then the pre-allocator will allocate the
> > > memory via dma_alloc_coherent() with the givn device. If it's not
> > > appropriate, SNDRV_DMA_TYPE_CONTINUOUS type. Anyway,
> > > snd_dma_continuous_data() is only for SNDRV_DMA_TYPE_CONTINUOUS.
> > Ok, applied. Using &chip->spi->dev.
> Not that I think it matters at the moment, but that's not entirely
> correct. The memory is used for DMA transfers to the SSC controller,
> not the SPI device, so you should pass the SSC's struct device here.
> In other words, I think you should use &chip->ssc->pdev->dev.
Hmm, my fault, applied.
New patch attached.
With kind regards,
Hans-Christian Egtvedt, siv.ing. (M.Sc.)
Applications Engineer - AVR32 System Solutions - Atmel Norway
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