From: "jonsmirl@gmail.com" <jonsmirl@gmail.com>
To: ARM Linux Mailing List <linux-arm-kernel@lists.infradead.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: DMAEngine and channel pairs
Date: Wed, 6 Feb 2013 23:27:10 -0500 [thread overview]
Message-ID: <CAKON4Oxmvc3ShbFVoeGH5ftcDNPSi9TN0bLp0bL9GF6yyTwF1w@mail.gmail.com> (raw)
The CPU I'm working on uses two sequential DMA channels to implement
scatter-gather. How do you handle this in the channel allocator? If
scatter-gather is not requested the two channels work fine as normal
DMA channels.
So when a scatter-gather channel is requested my driver needs to fail
the dma_alloc_chan_resources() requests until a sequential pair is
located? Plus I need to track what channels are used in my driver so
that I know where sequential pairs are. Is there a better way to do
this?
Another solution might be to statically allocate some channels as
being scatter/gather capable and others as not being able to do it. I
would just report fewer available channels to dmaengine and hide those
secondary channels from it. I have 12 channels to work with.
--
Jon Smirl
jonsmirl@gmail.com
reply other threads:[~2013-02-07 4:27 UTC|newest]
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