[PATCH v4] dma: Add Xilinx AXI Direct Memory Access Engine driver support

Ping !

-----Original Message-----
From: Michal Simek [mailto:michal.simek at xilinx.com]
Sent: Friday, February 20, 2015 4:13 PM
To: Vinod Koul; Appana Durga Kedareswara Rao
Cc: Arnd Bergmann; linux-arm-kernel at lists.infradead.org;
devicetree at vger.kernel.org; Srikanth Vemula; linux-
kernel at vger.kernel.org; Srikanth Thokala; dmaengine at vger.kernel.org;
robh+dt at kernel.org; Anirudha Sarangi; grant.likely at linaro.org;
dan.j.williams at intel.com
Subject: Re: [PATCH v4] dma: Add Xilinx AXI Direct Memory Access Engine
driver support

Hi Vinod,

On 02/20/2015 07:29 AM, Vinod Koul wrote:

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On Sat, Feb 14, 2015 at 02:21:52PM +0000, Appana Durga Kedareswara Rao

wrote:

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Hi Vinod,

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-----Original Message-----
From: Vinod Koul [mailto:vinod.koul at intel.com]
Sent: Thursday, February 12, 2015 3:05 PM
To: Appana Durga Kedareswara Rao
Cc: Arnd Bergmann; linux-arm-kernel at lists.infradead.org;
devicetree at vger.kernel.org; Srikanth Vemula; linux-
kernel at vger.kernel.org; Srikanth Thokala; dmaengine at vger.kernel.org;
robh+dt at kernel.org; Michal Simek; Anirudha Sarangi;
grant.likely at linaro.org; dan.j.williams at intel.com
Subject: Re: [PATCH v4] dma: Add Xilinx AXI Direct Memory Access
Engine driver support

On Thu, Jan 29, 2015 at 11:24:41AM +0000, Appana Durga Kedareswara
Rao
wrote:

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 Earlier in the driver we are embedding dma_slave_config into
custom structs But Lars suggested to modify it. please refer to
the below thread for more details.
 http://www.spinics.net/lists/dmaengine/msg00010.html

 And later we thought of creating a separate private member in
dma_slave_config for sharing additional configuration between
slave device and dma engine Or a new dma_ctrl_cmd like

FSLDMA_EXTERNAL_START(http://www.kernelhub.org/?msg=405535&p=2 )

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 Finally Vinod was ok with the existing suggestion so we dropped
the above thought.

 @Vinod : Could you please comment on this.

FSLDMA_EXTERNAL_START has been removed, and you cna use the

removal

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as a guidance of how to solve your issue

Please limit you mailer to set wrap at 80 chars, otherwise it becomes
unreadable

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The current VDMA driver that got merged in the open source and the
current patch (dma: xilinx dma v4) Srikanth T submitted both contains
the Similar implementation that you pointed as above(I mean similar
to the free scale dma driver).

The discussion starts here is why we need the header
file(Xilinx_dma.h) in the include/linux/amba/Xilinx_dma.h  folder.

Like for FSL DMA it is got defined (fsl_dma_external_start) as a
function prototype in include/linux/fsldma.h And it is being getting
used in the drivers/misc/carma/carma-fpga-program.c

Similarly in the Xilinx VDMA driver(xilinx_vdma_channel_set_config )
defined as a function prototype in the
include/linux/amba/xilinx_dma.h And is being used by Xilinx videos
drivers.  Those video driver need to use the
(xilinx_vdma_channel_set_config) which requires this global header file.

Could you please suggest us whether that header file (Xilinx_dma.h)
should be there  in include/linux/amba or we should move it to

include/linux?

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And any functional comments for this v4 patch?

Let me ask you a question, what is the relation of xilinx_dma with amba?

If none then only include/linux/ seems to be the right choice. If not
then amba maybe okay but you need to provide justfication why it should

be in amba?

I see your point. I think there is real reason to have this header in amba.
The reason for that was that xilinx_dma.h was added there.

Anyway there is include/linux/dma/ folder. Is it ok to move xilinx_dma.h
there too? The same with this dma one.

Thanks,
Michal

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