Messages in this thread | | | Date | Wed, 30 Oct 2019 08:29:32 -0500 | From | Rob Herring <> | Subject | Re: [RFC][PATCH 1/3] dt-bindings: dma-buf: heaps: Describe CMA regions to be added to dmabuf heaps interface. |
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On Fri, Oct 25, 2019 at 04:55:35PM -0700, John Stultz wrote: > On Fri, Oct 25, 2019 at 4:32 PM Rob Herring <rob.e.herring@gmail.com> wrote: > > > > On Fri, Oct 25, 2019 at 5:51 PM John Stultz <john.stultz@linaro.org> wrote: > > > > > > This binding specifies which CMA regions should be added to the > > > dmabuf heaps interface. > > > > Is this an ION DT binding in disguise? I thought I killed that. ;) > > Maybe? I may not have been paying attention back then. :) > > > > +Example: > > > +This example has a camera CMA node in reserved memory, which is then > > > +referenced by the dmabuf-heap-cma node. > > > + > > > + > > > + reserved-memory { > > > + #address-cells = <2>; > > > + #size-cells = <2>; > > > + ranges; > > > + ... > > > + cma_camera: cma-camera { > > > + compatible = "shared-dma-pool"; > > > + reg = <0x0 0x24C00000 0x0 0x4000000>; > > > + reusable; > > > + }; > > > + ... > > > + }; > > > + > > > + cma_heap { > > > + compatible = "dmabuf-heap-cma"; > > > + memory-region = <&cma_camera>; > > > > Why the indirection here? Can't you just add a flag property to > > reserved-memory nodes like we do to flag CMA nodes? > > Happy to try. Do you mean like with the "reuasable" tag? Or more like > the "linux,cma-default" tag?
Probably like "linux,cma-default" as it is a hint for who to manage it rather than a characteristic of the region.
> Do you have a preference for the flag name here?
Not really.
> > As I suspected, it's because in patch 2 you're just abusing DT to > > instantiate platform devices. We already support binding drivers to > > reserved-memory nodes directly. > > Sorry, one of those "when all you know how to do is hammer, everything > looks like a nail" issues. > Is there a specific example for binding drivers to reserved-memory > nodes I can try to follow?
ramoops and I think there's a QCom driver.
Rob
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