xref: /freebsd/sys/contrib/device-tree/Bindings/interconnect/interconnect.txt (revision 3078531de10dcae44b253a35125c949ff4235284)
1Interconnect Provider Device Tree Bindings
2=========================================
3
4The purpose of this document is to define a common set of generic interconnect
5providers/consumers properties.
6
7
8= interconnect providers =
9
10The interconnect provider binding is intended to represent the interconnect
11controllers in the system. Each provider registers a set of interconnect
12nodes, which expose the interconnect related capabilities of the interconnect
13to consumer drivers. These capabilities can be throughput, latency, priority
14etc. The consumer drivers set constraints on interconnect path (or endpoints)
15depending on the use case. Interconnect providers can also be interconnect
16consumers, such as in the case where two network-on-chip fabrics interface
17directly.
18
19Required properties:
20- compatible : contains the interconnect provider compatible string
21- #interconnect-cells : number of cells in a interconnect specifier needed to
22			encode the interconnect node id and optionally add a
23			path tag
24
25Example:
26
27		snoc: interconnect@580000 {
28			compatible = "qcom,msm8916-snoc";
29			#interconnect-cells = <1>;
30			reg = <0x580000 0x14000>;
31			clock-names = "bus_clk", "bus_a_clk";
32			clocks = <&rpmcc RPM_SMD_SNOC_CLK>,
33				 <&rpmcc RPM_SMD_SNOC_A_CLK>;
34		};
35
36
37= interconnect consumers =
38
39The interconnect consumers are device nodes which dynamically express their
40bandwidth requirements along interconnect paths they are connected to. There
41can be multiple interconnect providers on a SoC and the consumer may consume
42multiple paths from different providers depending on use case and the
43components it has to interact with.
44
45Required properties:
46interconnects : Pairs of phandles and interconnect provider specifier to denote
47	        the edge source and destination ports of the interconnect path.
48		An optional path tag value could specified as additional argument
49		to both endpoints and in such cases, this information will be passed
50		to the interconnect framework to do aggregation based on the attached
51		tag.
52
53Optional properties:
54interconnect-names : List of interconnect path name strings sorted in the same
55		     order as the interconnects property. Consumers drivers will use
56		     interconnect-names to match interconnect paths with interconnect
57		     specifier pairs.
58
59                     Reserved interconnect names:
60			 * dma-mem: Path from the device to the main memory of
61			            the system
62
63Example:
64
65	sdhci@7864000 {
66		...
67		interconnects = <&pnoc MASTER_SDCC_1 &bimc SLAVE_EBI_CH0>;
68		interconnect-names = "sdhc-mem";
69	};
70
71Example with path tags:
72
73	gnoc: interconnect@17900000 {
74		...
75		interconnect-cells = <2>;
76	};
77
78	mnoc: interconnect@1380000 {
79		...
80		interconnect-cells = <2>;
81	};
82
83	cpu@0 {
84		...
85		interconnects = <&gnoc MASTER_APPSS_PROC 3 &mnoc SLAVE_EBI1 3>;
86	}
87