[PATCH v4] dma: Add Xilinx AXI Direct Memory Access Engine driver support
Appana Durga Kedareswara Rao
appana.durga.rao at xilinx.com
Mon Mar 2 01:04:37 PST 2015
> -----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:
> > On Sat, Feb 14, 2015 at 02:21:52PM +0000, Appana Durga Kedareswara Rao
> >> Hi Vinod,
> >>> -----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:
> >>>>> 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 )
> >>>>> 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
> >>> as a guidance of how to solve your issue
> > Please limit you mailer to set wrap at 80 chars, otherwise it becomes
> > unreadable
> >> 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
> >> 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.
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