Messages in this thread | | | From | Rob Herring <> | Date | Tue, 25 Feb 2020 12:55:08 -0600 | Subject | Re: [PATCH v2 2/4] dt-bindings: display: msm: Add required dma-range property |
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On Thu, Feb 20, 2020 at 12:27 PM Jordan Crouse <jcrouse@codeaurora.org> wrote: > > The GMU node now requires a specific dma-range property so that the driver
s/dma-range/dma-ranges/ here and the subject.
> can use the DMA API to do the few memory allocations required by the GMU. > This sets the IOMMU iova allocator to match the 'uncached' part of the > GMU virtual address space.
Sounds like a bunch of kernel things and this is a binding.
> > v2: Fix the dma-ranges tag. The third pair should be the size. > > Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org> > --- > > Documentation/devicetree/bindings/display/msm/gmu.yaml | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/Documentation/devicetree/bindings/display/msm/gmu.yaml b/Documentation/devicetree/bindings/display/msm/gmu.yaml > index 776ff92..d11a073 100644 > --- a/Documentation/devicetree/bindings/display/msm/gmu.yaml > +++ b/Documentation/devicetree/bindings/display/msm/gmu.yaml > @@ -83,6 +83,13 @@ properties: > Phandle to the OPP table for the available GMU frequencies. Refer to > ../../opp/opp.txt for more information. > > + dma-ranges:
dma-ranges is a bus property and doesn't go in device nodes (that don't implement a bus like PCI host for example). This would not have even worked a few kernel versions back because the kernel would only start looking for dma-ranges in a parent node.
> + $ref: /schemas/types.yaml#/definitions/uint32-array > + description: > + Describe the dma-address range for the device. This should always > + describe the range between 0x60000000 and 0x80000000 which represents
If this is always the region, then why does it need to be in DT? Just set your dma_mask which drivers should be doing if they want anything other than (2^32 - 1). dma-ranges sets the bus_dma_mask.
> + the uncached region of the GMU address space. > + > required: > - compatible > - reg > @@ -95,6 +102,7 @@ required: > - power-domain-names > - iommus > - operating-points-v2 > + - dma-ranges > > examples: > - | > @@ -127,4 +135,6 @@ examples: > > iommus = <&adreno_smmu 5>; > operating-points-v2 = <&gmu_opp_table>; > + > + dma-ranges = <0 0x60000000 0 0x60000000 0 0x20000000>; > }; > -- > 2.7.4 >
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