1Qualcomm Shared Memory Driver (SMD) binding
2
3This binding describes the Qualcomm Shared Memory Driver, a fifo based
4communication channel for sending data between the various subsystems in
5Qualcomm platforms.
6
7- compatible:
8	Usage: required
9	Value type: <stringlist>
10	Definition: must be "qcom,smd"
11
12= EDGES
13
14Each subnode of the SMD node represents a remote subsystem or a remote
15processor of some sort - or in SMD language an "edge". The name of the edges
16are not important.
17The edge is described by the following properties:
18
19- interrupts:
20	Usage: required
21	Value type: <prop-encoded-array>
22	Definition: should specify the IRQ used by the remote processor to
23		    signal this processor about communication related updates
24
25- qcom,ipc:
26	Usage: required
27	Value type: <prop-encoded-array>
28	Definition: three entries specifying the outgoing ipc bit used for
29		    signaling the remote processor:
30		    - phandle to a syscon node representing the apcs registers
31		    - u32 representing offset to the register within the syscon
32		    - u32 representing the ipc bit within the register
33
34- qcom,smd-edge:
35	Usage: required
36	Value type: <u32>
37	Definition: the identifier of the remote processor in the smd channel
38		    allocation table
39
40- qcom,remote-pid:
41	Usage: optional
42	Value type: <u32>
43	Definition: the identifier for the remote processor as known by the rest
44		    of the system.
45
46= SMD DEVICES
47
48In turn, subnodes of the "edges" represent devices tied to SMD channels on that
49"edge". The names of the devices are not important. The properties of these
50nodes are defined by the individual bindings for the SMD devices - but must
51contain the following property:
52
53- qcom,smd-channels:
54	Usage: required
55	Value type: <stringlist>
56	Definition: a list of channels tied to this device, used for matching
57		    the device to channels
58
59= EXAMPLE
60
61The following example represents a smd node, with one edge representing the
62"rpm" subsystem. For the "rpm" subsystem we have a device tied to the
63"rpm_request" channel.
64
65	apcs: syscon@f9011000 {
66		compatible = "syscon";
67		reg = <0xf9011000 0x1000>;
68	};
69
70	smd {
71		compatible = "qcom,smd";
72
73		rpm {
74			interrupts = <0 168 1>;
75			qcom,ipc = <&apcs 8 0>;
76			qcom,smd-edge = <15>;
77
78			rpm_requests {
79				compatible = "qcom,rpm-msm8974";
80				qcom,smd-channels = "rpm_requests";
81
82				...
83			};
84		};
85	};
86