Messages in this thread | | | Date | Tue, 21 Feb 2023 19:51:56 -0800 | Subject | Re: [RESEND PATCH V12 XDMA 1/2] dmaengine: xilinx: xdma: Add xilinx xdma driver | From | Lizhi Hou <> |
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On 2/21/23 13:46, Martin Tůma wrote: > On 21. 02. 23 22:06, Geert Uytterhoeven wrote: >> Hi Martin, >> >> On Tue, Feb 21, 2023 at 9:45 PM Martin Tůma <tumic@gpxsee.org> wrote: >>> On 21. 02. 23 14:25, Geert Uytterhoeven wrote: >>>> No platform dependencies at all, while this is a platform driver that >>>> relies on some other not-yet-existing driver creating an "xdma" >>>> platform device? >>> >>> There is at least one "already-existing" driver based on this driver >>> that is waiting in the v4l2 queue for xdma - our MGB4 driver: >>> https://patchwork.kernel.org/project/linux-media/patch/20230207150119.5542-2-tumic@gpxsee.org/ >>> >> >> Thanks for the link! >> >> As VIDEO_MGB4 selects XILINX_XDMA, perhaps XILINX_XDMA >> can be made invisible, unless compile-testing? >> >> config XILINX_XDMA >> tristate "Xilinx DMA/Bridge Subsystem DMA Engine" if >> COMPILE_TEST >> >> Gr{oetje,eeting}s, >> >> Geert >> > > Hi, > I think that the XDMA driver will always be used by a superior PCIe > card driver like in our case (mgb4) and using it separately makes no > sense/is not possible, so disabling it until some of the superior > drivers selects it makes sense for me. But what about out-of-the-tree > modules based on xdma? Making the module "invisible" will make compile > them much harder I guess? And there will be proprietary drivers based > on xdma, see Xilinx XRT: > https://github.com/houlz0507/XRT-1/tree/xdma_v4_usage > > The xdma authors from Xilinx will definitely give you a more > authoritative answer. I'm just a "random" user of the xdma module. > Originally our mgb4 driver was based on our own xdma sub-driver (in > turn based on some old "test" driver from Xilinx) which I was glad we > could abandon when this xdma driver has appeared. I helped the xdma > module to become usable for PCIe cards like our v4l2 grabber, but the > original intents of the xdma driver are unknown to me. If it is XRT, > than Xilinx will probably like the module to stay visible. > > M. > There are PCIe devices which use the XDMA IP and would use this xdma driver. Out of tree drivers for Xilinx/AMD Alveo devices can switch to this in kernel xdma driver.
Thanks,
Lizhi
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