From: Kuninori Morimoto <kuninori.morimoto.gx@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Linux-ALSA <alsa-devel@alsa-project.org>,
Lars-Peter Clausen <lars@metafoo.de>,
Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
Simon <horms@verge.net.au>, Liam Girdwood <lgirdwood@gmail.com>
Subject: Re: About snd_dmaengine_pcm_trigger()
Date: Tue, 11 Mar 2014 17:28:07 -0700 (PDT) [thread overview]
Message-ID: <878usgs1kg.wl%kuninori.morimoto.gx@gmail.com> (raw)
In-Reply-To: <20140311095555.GI28112@sirena.org.uk>
Hi Lars, Mark
> > The reason why we factored out the dmaengine DMA stuff is because
> > there is a standard API that hides the implementation details and is
> > supposed to behave the same for each system. For PIO you do not have
> > such a abstraction layer that hides the details, so I'm not sure how
> > similar PIO between different platforms will actually be.
>
> I keep thinking that there ought to be *some* commonality between the
> platforms that use FIQs if only in the timer stuff at least. Part of
> the reason that doesn't get factored out is that it's normally just a
> temporary bodge until DMA is working of course, though Qualcomm do it
> because their DMA for the DSP doesn't fit well with dmaengine and the
> i.MX AC'97 needs it since the hardware doesn't fully understand AC'97.
Yes, there is no pioengine (never created :)
I'm not sure detail of non-Renesas platform driver whether it is supporting PIO.
But at least my driver (= FSI/rcar) has PIO support,
and I think these can share same method/function.
So, I create pcm_pio.c under ${LINUX}/sound/soc/sh for Renesas chip
with pcm_dmaengine similar style (as much as possible).
And, use common ${LINUX}/sound/core/pcm_dmaengine.c for DMA.
How about this ?
prev parent reply other threads:[~2014-03-12 0:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-05 5:20 About snd_dmaengine_pcm_trigger() Kuninori Morimoto
2014-03-05 7:42 ` Lars-Peter Clausen
2014-03-05 8:32 ` Kuninori Morimoto
2014-03-05 9:20 ` Lars-Peter Clausen
2014-03-06 0:22 ` Kuninori Morimoto
2014-03-06 4:36 ` Mark Brown
2014-03-06 4:39 ` Kuninori Morimoto
2014-03-11 4:47 ` Kuninori Morimoto
2014-03-11 9:47 ` Lars-Peter Clausen
2014-03-11 9:55 ` Mark Brown
2014-03-12 0:28 ` Kuninori Morimoto [this message]
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