This documents a device tree binding for the Qualcomm Shared Memory State Machine. Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx> --- Changes since v1: - No longer representing outgoing state as gpio-controller .../devicetree/bindings/soc/qcom/qcom,smsm.txt | 104 +++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 Documentation/devicetree/bindings/soc/qcom/qcom,smsm.txt diff --git a/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.txt b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.txt new file mode 100644 index 000000000000..a6634c70850d --- /dev/null +++ b/Documentation/devicetree/bindings/soc/qcom/qcom,smsm.txt @@ -0,0 +1,104 @@ +Qualcomm Shared Memory State Machine + +The Shared Memory State Machine facilitates broadcasting of single bit state +information between the processors in a Qualcomm SoC. Each processor is +assigned 32 bits of state that can be modified. A processor can through a +matrix of bitmaps signal subscription of notifications upon changes to a +certain bit owned by a certain remote processor. + +- compatible: + Usage: required + Value type: <string> + Definition: must be one of: + "qcom,smsm" + +- qcom,ipc-N: + Usage: required + Value type: <prop-encoded-array> + Definition: three entries specifying the outgoing ipc bit used for + signaling the N:th remote processor + - 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,local-host: + Usage: optional + Value type: <u32> + Definition: identifier of the local processor in the list of hosts, or + in other words specifier of the column in the subscription + matrix representing the local processor + defaults to host 0 + +- #address-cells: + Usage: required + Value type: <u32> + Definition: must be 1 + +- #size-cells: + Usage: required + Value type: <u32> + Definition: must be 0 + += SUBNODES +Each processor's state bits are described by a subnode of the smsm device node. +Nodes can either be flagged as an interrupt-controller to denote a remote +processor's state bits or the local processors bits. The node names are not +important. + +- reg: + Usage: required + Value type: <u32> + Definition: specifies the offset, in words, of the first bit for this + entry + +- #qcom,state-cells: + Usage: required for local entry + Value type: <u32> + Definition: must be 1 - denotes bit number + +- interrupt-controller: + Usage: required for remote entries + Value type: <empty> + Definition: marks the entry as a interrupt-controller and the state bits + to belong to a remote processor + +- #interrupt-cells: + Usage: required for remote entries + Value type: <u32> + Definition: must be 2 - denotes bit number and IRQ flags + +- interrupts: + Usage: required for remote entries + Value type: <prop-encoded-array> + Definition: one entry specifying remote IRQ used by the remote processor + to signal changes of its state bits + + += EXAMPLE +The following example shows the SMEM setup for controlling properties of the +wireless processor, defined from the 8974 apps processor's point-of-view. It +encompasses one outbound entry and the outgoing interrupt for the wireless +processor. + +smsm { + compatible = "qcom,smsm"; + + #address-cells = <1>; + #size-cells = <0>; + + qcom,ipc-3 = <&apcs 8 19>; + + apps_smsm: apps@0 { + reg = <0>; + + #qcom,state-cells = <1>; + }; + + wcnss_smsm: wcnss@7 { + reg = <7>; + interrupts = <0 144 1>; + + interrupt-controller; + #interrupt-cells = <2>; + }; +}; -- 1.8.2.2 -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html