Hi Rob, On Sunday 09 March 2014 01:23 AM, Rob Herring wrote: > On Fri, Mar 7, 2014 at 6:16 AM, Sricharan R <r.sricharan@xxxxxx> wrote: >> In some SoCs the dma request lines from the peripherals are >> routed to the dma-controller through a crossbar. With this the >> dma controller's available request lines are shared between the >> peripherals. >> >> This adds support to register the crossbar router associated with >> a dma-channel and let the dma-controller driver map/unmap >> the peripheral dma crossbar line to dma-controller's request >> line. > This is not a unique concept and should follow some existing pattern. > Perhaps something like interrupt-map. For the dmas property, the > parent should be the crossbar and then the crossbar block has to > translate that into the DMA controller request. All the DMA ctrlr > request connections should be described in the crossbar node. In > theory, you could have chained crossbars. This should be documented as > part of the generic DMA binding. The idea here was to do the map/unmap crossbar<->dma-request from the dma-controller at runtime just like any other resource, unlike interrupt-map fixed in DTS. I did not think about the chained crossbars case. I will add this here. And as you have suggested will make it work like irq_parse_and_map. Regards, Sricharan > There are also other similar IP like CoreSight CTI which are just > signal routers. So there is probably some possibility of common code > here. > > Rob -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
