1Qualcomm Shared Memory Point 2 Point binding 2 3The Shared Memory Point to Point (SMP2P) protocol facilitates communication of 4a single 32-bit value between two processors. Each value has a single writer 5(the local side) and a single reader (the remote side). Values are uniquely 6identified in the system by the directed edge (local processor ID to remote 7processor ID) and a string identifier. 8 9- compatible: 10 Usage: required 11 Value type: <string> 12 Definition: must be one of: 13 "qcom,smp2p" 14 15- interrupts: 16 Usage: required 17 Value type: <prop-encoded-array> 18 Definition: one entry specifying the smp2p notification interrupt 19 20- mboxes: 21 Usage: required 22 Value type: <prop-encoded-array> 23 Definition: reference to the associated doorbell in APCS, as described 24 in mailbox/mailbox.txt 25 26- qcom,ipc: 27 Usage: required, unless mboxes is specified 28 Value type: <prop-encoded-array> 29 Definition: three entries specifying the outgoing ipc bit used for 30 signaling the remote end of the smp2p edge: 31 - phandle to a syscon node representing the apcs registers 32 - u32 representing offset to the register within the syscon 33 - u32 representing the ipc bit within the register 34 35- qcom,smem: 36 Usage: required 37 Value type: <u32 array> 38 Definition: two identifiers of the inbound and outbound smem items used 39 for this edge 40 41- qcom,local-pid: 42 Usage: required 43 Value type: <u32> 44 Definition: specifies the identifier of the local endpoint of this edge 45 46- qcom,remote-pid: 47 Usage: required 48 Value type: <u32> 49 Definition: specifies the identifier of the remote endpoint of this edge 50 51= SUBNODES 52Each SMP2P pair contain a set of inbound and outbound entries, these are 53described in subnodes of the smp2p device node. The node names are not 54important. 55 56- qcom,entry-name: 57 Usage: required 58 Value type: <string> 59 Definition: specifies the name of this entry, for inbound entries this 60 will be used to match against the remotely allocated entry 61 and for outbound entries this name is used for allocating 62 entries 63 64- interrupt-controller: 65 Usage: required for incoming entries 66 Value type: <empty> 67 Definition: marks the entry as inbound; the node should be specified 68 as a two cell interrupt-controller as defined in 69 "../interrupt-controller/interrupts.txt" 70 If not specified this node will denote the outgoing entry 71 72- #interrupt-cells: 73 Usage: required for incoming entries 74 Value type: <u32> 75 Definition: must be 2 - denoting the bit in the entry and IRQ flags 76 77- #qcom,smem-state-cells: 78 Usage: required for outgoing entries 79 Value type: <u32> 80 Definition: must be 1 - denoting the bit in the entry 81 82= EXAMPLE 83The following example shows the SMP2P setup with the wireless processor, 84defined from the 8974 apps processor's point-of-view. It encompasses one 85inbound and one outbound entry: 86 87wcnss-smp2p { 88 compatible = "qcom,smp2p"; 89 qcom,smem = <431>, <451>; 90 91 interrupts = <0 143 1>; 92 93 qcom,ipc = <&apcs 8 18>; 94 95 qcom,local-pid = <0>; 96 qcom,remote-pid = <4>; 97 98 wcnss_smp2p_out: master-kernel { 99 qcom,entry-name = "master-kernel"; 100 101 #qcom,smem-state-cells = <1>; 102 }; 103 104 wcnss_smp2p_in: slave-kernel { 105 qcom,entry-name = "slave-kernel"; 106 107 interrupt-controller; 108 #interrupt-cells = <2>; 109 }; 110}; 111