RE: [PATCH v4] dma: Add Xilinx AXI Direct Memory Access Engine driver support
From: Appana Durga Kedareswara Rao
Date: Sat Feb 14 2015 - 09:22:12 EST
> -----Original Message-----
> From: Vinod Koul [mailto:vinod.koul@xxxxxxxxx]
> Sent: Thursday, February 12, 2015 3:05 PM
> To: Appana Durga Kedareswara Rao
> Cc: Arnd Bergmann; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx;
> devicetree@xxxxxxxxxxxxxxx; Srikanth Vemula; linux-
> kernel@xxxxxxxxxxxxxxx; Srikanth Thokala; dmaengine@xxxxxxxxxxxxxxx;
> robh+dt@xxxxxxxxxx; Michal Simek; Anirudha Sarangi;
> grant.likely@xxxxxxxxxx; dan.j.williams@xxxxxxxxx
> 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
> > > 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 removal
> as a guidance of how to solve your issue
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?
And any functional comments for this v4 patch?
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