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MIME-Version: 1.0
Date: Fri, 17 Jul 2009 12:33:25 +0200
Message-ID: <35e3b0c00907170333p79c5387bk72f9df453bc0ec83@mail.gmail.com>
Subject: Intended usage of the dmaengine
From: Per Forlin <per.lkml@gmail.com>
To: dan.j.williams@intel.com
Cc: haavard.skinnemoen@atmel.com, linux-kernel@vger.kernel.org
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Hi,

I work with Linux in embedded systems and I got more interested in
dmaengine after Haavard Skinnemoen added the DMA SLAVE support. DMA
SLAVE opens up the dmaengine for embedded users and I wonder if there
is more room for support towards the embedded world. I've made a test
implementation of the dmaengine for our DMAC. Some parts that weren't
supported by the dmaengine had to be exported by the driver code. A
similar example of this is cyclic DMA jobs in dw_dmac.h.
Is this the preferable way to handle it? Or could this functionality
be added to the dmaengine instead?

Additional support that I would like to have in the "struct dma_engine" is
* stopping the dma channel transfer
* continue a stopped transfer
* PER2PER transfers (dma transfer between two peripherals)
* dma transfers from phy mem to per, and per to phy mem
* function to return the transfer count of an active dma transfer
(useful when the dma channel has been stopped deliberately)

I am willing to propose and contribute updates to the dmaengine
regarding this matter. With this email I would like to check with you
whether these types of new support are welcome in the dmaengine.

Thank you for your time and interest,
Per

PS
Dan and Haavard, I apologise for resending this email. I forgot to
send the email as plain text.
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