linux/Documentation/devicetree/bindings/interconnect/interconnect.txt
Maxime Ripard c43a446940 dt-bindings: interconnect: Add a dma interconnect name
The current DT bindings assume that the DMA will be performed by the
devices through their parent DT node, and rely on that assumption for the
address translation using dma-ranges.

However, some SoCs have devices that will perform DMA through another bus,
with separate address translation rules. We therefore need to express that
relationship, through the special interconnect name "dma-mem".

Acked-by: Georgi Djakov <georgi.djakov@linaro.org>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Rob Herring <robh@kernel.org>
2019-04-10 16:33:47 -05:00

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Interconnect Provider Device Tree Bindings
=========================================
The purpose of this document is to define a common set of generic interconnect
providers/consumers properties.
= interconnect providers =
The interconnect provider binding is intended to represent the interconnect
controllers in the system. Each provider registers a set of interconnect
nodes, which expose the interconnect related capabilities of the interconnect
to consumer drivers. These capabilities can be throughput, latency, priority
etc. The consumer drivers set constraints on interconnect path (or endpoints)
depending on the use case. Interconnect providers can also be interconnect
consumers, such as in the case where two network-on-chip fabrics interface
directly.
Required properties:
- compatible : contains the interconnect provider compatible string
- #interconnect-cells : number of cells in a interconnect specifier needed to
encode the interconnect node id
Example:
snoc: interconnect@580000 {
compatible = "qcom,msm8916-snoc";
#interconnect-cells = <1>;
reg = <0x580000 0x14000>;
clock-names = "bus_clk", "bus_a_clk";
clocks = <&rpmcc RPM_SMD_SNOC_CLK>,
<&rpmcc RPM_SMD_SNOC_A_CLK>;
};
= interconnect consumers =
The interconnect consumers are device nodes which dynamically express their
bandwidth requirements along interconnect paths they are connected to. There
can be multiple interconnect providers on a SoC and the consumer may consume
multiple paths from different providers depending on use case and the
components it has to interact with.
Required properties:
interconnects : Pairs of phandles and interconnect provider specifier to denote
the edge source and destination ports of the interconnect path.
Optional properties:
interconnect-names : List of interconnect path name strings sorted in the same
order as the interconnects property. Consumers drivers will use
interconnect-names to match interconnect paths with interconnect
specifier pairs.
Reserved interconnect names:
* dma-mem: Path from the device to the main memory of
the system
Example:
sdhci@7864000 {
...
interconnects = <&pnoc MASTER_SDCC_1 &bimc SLAVE_EBI_CH0>;
interconnect-names = "sdhc-mem";
};