[alsa-devel] [PATCH v5 0/5] OMAP/ASoC: McBSP: FIFO handling related fixes
lrg at slimlogic.co.uk
Thu Jun 3 17:17:30 CEST 2010
On Thu, 2010-06-03 at 07:39 +0300, Peter Ujfalusi wrote:
> Tony: Could you take a look at the arch/arm patches in this series?
> Changes since v3/4:
> - Fixed commit subjects and messages for OMAP3 related patches
> - Added Acked-by from Mark, and Jarkko
> Intro message from the original series:
> This series aims to correct how the McBSP FIFO is viewed, and handled.
> Introduction of the problem:
> OMAP McBSP FIFO is word structured:
> McBSP2 has 1024 + 256 = 1280 word long buffer,
> McBSP1,3,4,5 has 128 word long buffer
> This means, that the size of the FIFO
> depends on the McBSP word size configuration.
> For example on McBSP3:
> 16bit samples: size is 128 * 2 = 256 bytes
> 32bit samples: size is 128 * 4 = 512 bytes
> It is simpler to place constraint for buffer and period based on channels.
> McBSP3 as example again (16 or 32 bit samples):
> 1 channel (mono): size is 128 frames (128 words)
> 2 channels (stereo): size is 128 / 2 = 64 frames (2 * 64 words)
> 4 channels: size is 128 / 4 = 32 frames (4 * 32 words)
> Since now the McBSP codec supports not only 16bit samples (32biut has been
> recently added), the FIFO size handling is no longer correct, since it has
> been hard wired for 16bit word length.
> The series changes how the users of McBSP are configuring the FIFO:
> It used to be 0 based (0 meant 1 word threshold). After this series users can
> configure the threshold in 1 base mode (1 means 1 word threshold).
> The platform code now provides the full size of the FIFO in words, instead of
> the already limited value used in the past.
> In ASoC omap-mcbsp code hw_rule based constraint refinement is going to be used
> instead of the hardwired static constraint, which was correct only in case of
> 16bit word length.
> The hw_rule is refining the minimum buffer size based on the channel number
> going to be used by the coming stream.
> In case of threshold mode additional hw_rule refines the maximum allowed period
> The series are generated agains Takashi's sound-2.6: topic/asoc branch.
> CCing also Eduardo, and Eero since they have worked on the original
> FIFO/threshold implementation.
> All commetns and testers are welcome!
> Peter Ujfalusi (5):
> OMAP: McBSP: Function to query the FIFO size
> OMAP3: McBSP: Change the way how the FIFO is handled
> OMAP3: McBSP: Use the port's buffer_size when calculating tx delay
> ASoC: omap-mcbsp: Save, and use wlen for threshold configuration
> ASoC: omap-mcbsp: Place correct constraints for streams
> arch/arm/mach-omap2/mcbsp.c | 10 ++--
> arch/arm/plat-omap/include/plat/mcbsp.h | 2 +
> arch/arm/plat-omap/mcbsp.c | 51 ++++++++++-----
> sound/soc/omap/omap-mcbsp.c | 112 +++++++++++++++++++++++-------
> 4 files changed, 128 insertions(+), 47 deletions(-)
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ASoC and Voltage Regulator Maintainer.
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