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From: Lars-Peter Clausen <lars@metafoo.de>
To: Vinod Koul <vinod.koul@intel.com>, Russell King <linux@arm.linux.org.uk>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: How is dmaengine_prep_slave_single supposed to be used?
Date: Fri, 27 Jan 2012 15:32:51 +0100	[thread overview]
Message-ID: <4F22B593.3010402@metafoo.de> (raw)

Hi,

I've tried using dmaengine_prep_slave_single in one of my drivers an run
into an issue, the dma_address attribute of the sg element is not
initialized and thus the dma transfer and the DMA transfer fails.

Quoting from Documentation/dmaengine.txt:

   The peripheral driver is expected to have mapped the scatterlist for
   the DMA operation prior to calling device_prep_slave_sg, and must
   keep the scatterlist mapped until the DMA operation has completed.

So this is clearly not the case with dmaengine_prep_slave_single, so I'm
wondering how is ut supposed to be used and can it work properly at all?

Thanks,
- Lars

             reply	other threads:[~2012-01-27 14:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-27 14:32 Lars-Peter Clausen [this message]
2012-01-30  4:01 ` How is dmaengine_prep_slave_single supposed to be used? Vinod Koul

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