Hi, Please see my comments inline. On Fri, May 15, 2015 at 6:43 PM, Yong Wu <yong.wu@xxxxxxxxxxxx> wrote: > This patch add mediatek iommu dts binding document. > > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> > --- > .../devicetree/bindings/iommu/mediatek,iommu.txt | 51 ++++++++++ > include/dt-bindings/iommu/mt8173-iommu-port.h | 112 +++++++++++++++++++++ > 2 files changed, 163 insertions(+) > create mode 100644 Documentation/devicetree/bindings/iommu/mediatek,iommu.txt > create mode 100644 include/dt-bindings/iommu/mt8173-iommu-port.h > > diff --git a/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt b/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt > new file mode 100644 > index 0000000..f2cc7c0 > --- /dev/null > +++ b/Documentation/devicetree/bindings/iommu/mediatek,iommu.txt > @@ -0,0 +1,51 @@ > +/******************************************************/ > +/* Mediatek IOMMU Hardware Block Diagram */ > +/******************************************************/ nit: Could you follow one of existing styles of DT binding documentation? You might be able to use [1] as an example. [1] http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/iommu/arm,smmu.txt . > + EMI (External Memory Interface) > + | > + m4u (Multimedia Memory Management Unit) > + | > + smi (Smart Multimedia Interface) > + | > + +---------------+------- > + | | > + | | > + vdec larb disp larb ... SoCs have different local arbiter(larb). > + | | > + | | > + +----+----+ +-----+-----+ > + | | | | | | ... > + | | | | | | ... > + | | | | | | ... > + MC PP VLD OVL0 RDMA0 WDMA0 ... There are different ports in each larb. > + This diagram is still quite meaningless without proper description of all the functionality off all the blocks and interfaces between them. > +Required properties: > +- compatible : must be "mediatek,mt8173-m4u". > +- reg : m4u register base and size. > +- interrupts : the interrupt of m4u. > +- clocks : must contain one entry for each clock-names. > +- clock-names : must be "bclk", It is the block clock of m4u. > +- larb-portes-nr : must contain the number of the portes for each larb(local > + arbiter). The number is defined in dt-binding/iommu/mt8173-iommu-port.h. typo: Should it be "ports" instead of "portes"? Anyway, shouldn't this be a property of larb nodes? I.e. the larb0 node would have a port-count property set to M4U_LARB0_PORT_NR. > +- larb : must contain the local arbiters of the current platform. Refer to > + bindings/soc/mediatek/mediatek,smi.txt. It must sort according to the > + local arbiter index, like larb0, larb1, larb2... > +- iommu-cells : must be 1. Specifies the client PortID as defined in > + dt-binding/iommu/mt8173-iommu-port.h Looking at the driver, wouldn't a 2 cell system be more appropriate here? With first cell indexing the larbs and second the ports within that larb. [snip] > +#define M4U_LARB0_PORT_NR 8 > +#define M4U_LARB1_PORT_NR 10 > +#define M4U_LARB2_PORT_NR 21 > +#define M4U_LARB3_PORT_NR 15 > +#define M4U_LARB4_PORT_NR 6 > +#define M4U_LARB5_PORT_NR 9 > + > +#define M4U_LARB0_PORT(n) (n) > +#define M4U_LARB1_PORT(n) ((n) + M4U_LARB0_PORT_NR + M4U_LARB0_PORT(0)) > +#define M4U_LARB2_PORT(n) ((n) + M4U_LARB1_PORT_NR + M4U_LARB1_PORT(0)) > +#define M4U_LARB3_PORT(n) ((n) + M4U_LARB2_PORT_NR + M4U_LARB2_PORT(0)) > +#define M4U_LARB4_PORT(n) ((n) + M4U_LARB3_PORT_NR + M4U_LARB3_PORT(0)) > +#define M4U_LARB5_PORT(n) ((n) + M4U_LARB4_PORT_NR + M4U_LARB4_PORT(0)) This looks like some artificial indexing. Does it have any correspondence with actual hardware configuration? > + > +/* larb0 */ > +#define M4U_PORT_DISP_OVL0 M4U_LARB0_PORT(0) > +#define M4U_PORT_DISP_RDMA0 M4U_LARB0_PORT(1) > +#define M4U_PORT_DISP_WDMA0 M4U_LARB0_PORT(2) [snip] > +#define M4U_PORT_VENC_CUR_CHROMA_SET2 M4U_LARB5_PORT(6) > +#define M4U_PORT_VENC_RD_COMA_SET2 M4U_LARB5_PORT(7) > +#define M4U_PORT_VENC_SV_COMA_SET2 M4U_LARB5_PORT(8) This convinces me even more that this binding actually needs #iommu-cells to be 2 and the indexing system I described above. Best regards, Tomasz -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
