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diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smp2p.txt b/Documentation/devicetree/bindings/soc/qcom/qcom,smp2p.txt new file mode 100644 index 000000000..49e1d72d3 --- /dev/null +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smp2p.txt @@ -0,0 +1,110 @@ +Qualcomm Shared Memory Point 2 Point binding + +The Shared Memory Point to Point (SMP2P) protocol facilitates communication of +a single 32-bit value between two processors. Each value has a single writer +(the local side) and a single reader (the remote side). Values are uniquely +identified in the system by the directed edge (local processor ID to remote +processor ID) and a string identifier. + +- compatible: + Usage: required + Value type: <string> + Definition: must be one of: + "qcom,smp2p" + +- interrupts: + Usage: required + Value type: <prop-encoded-array> + Definition: one entry specifying the smp2p notification interrupt + +- mboxes: + Usage: required + Value type: <prop-encoded-array> + Definition: reference to the associated doorbell in APCS, as described + in mailbox/mailbox.txt + +- qcom,ipc: + Usage: required, unless mboxes is specified + Value type: <prop-encoded-array> + Definition: three entries specifying the outgoing ipc bit used for + signaling the remote end of the smp2p edge: + - phandle to a syscon node representing the apcs registers + - u32 representing offset to the register within the syscon + - u32 representing the ipc bit within the register + +- qcom,smem: + Usage: required + Value type: <u32 array> + Definition: two identifiers of the inbound and outbound smem items used + for this edge + +- qcom,local-pid: + Usage: required + Value type: <u32> + Definition: specifies the identifier of the local endpoint of this edge + +- qcom,remote-pid: + Usage: required + Value type: <u32> + Definition: specifies the identifier of the remote endpoint of this edge + += SUBNODES +Each SMP2P pair contain a set of inbound and outbound entries, these are +described in subnodes of the smp2p device node. The node names are not +important. + +- qcom,entry-name: + Usage: required + Value type: <string> + Definition: specifies the name of this entry, for inbound entries this + will be used to match against the remotely allocated entry + and for outbound entries this name is used for allocating + entries + +- interrupt-controller: + Usage: required for incoming entries + Value type: <empty> + Definition: marks the entry as inbound; the node should be specified + as a two cell interrupt-controller as defined in + "../interrupt-controller/interrupts.txt" + If not specified this node will denote the outgoing entry + +- #interrupt-cells: + Usage: required for incoming entries + Value type: <u32> + Definition: must be 2 - denoting the bit in the entry and IRQ flags + +- #qcom,smem-state-cells: + Usage: required for outgoing entries + Value type: <u32> + Definition: must be 1 - denoting the bit in the entry + += EXAMPLE +The following example shows the SMP2P setup with the wireless processor, +defined from the 8974 apps processor's point-of-view. It encompasses one +inbound and one outbound entry: + +wcnss-smp2p { + compatible = "qcom,smp2p"; + qcom,smem = <431>, <451>; + + interrupts = <0 143 1>; + + qcom,ipc = <&apcs 8 18>; + + qcom,local-pid = <0>; + qcom,remote-pid = <4>; + + wcnss_smp2p_out: master-kernel { + qcom,entry-name = "master-kernel"; + + #qcom,smem-state-cells = <1>; + }; + + wcnss_smp2p_in: slave-kernel { + qcom,entry-name = "slave-kernel"; + + interrupt-controller; + #interrupt-cells = <2>; + }; +}; |