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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
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treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /Documentation/devicetree/bindings/soc/qcom/qcom,smp2p.txt
parentInitial commit. (diff)
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Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+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 identfier of the local endpoint of this edge
+
+- qcom,remote-pid:
+ Usage: required
+ Value type: <u32>
+ Definition: specifies the identfier 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>;
+ };
+};