dt-bindings: qdsp: device-tree documentation for fastrpc nodes

Qualcomm Technologies, Inc. FastRPC Driver

The MSM FastRPC driver implements an IPC (Inter-Processor Communication)

mechanism that allows for clients to transparently make remote method

invocations across DSP and APPS boundaries. This enables developers

to offload tasks to the DSP and free up the application processor for

other tasks.

Required properties:

- compatible :	Must be one of "qcom,msm-fastrpc-adsp" or "qcom,msm-fastrpc-compute"

Optional properties:

- qcom,rpc-latency-us		:	FastRPC QoS latency vote

- qcom,adsp-remoteheap-vmid	:	FastRPC remote heap VMID list

- qcom,secure-context-bank	:	Bool indicating secure FastRPC context bank.

- qcom,fastrpc-legacy-remote-heap	:	Bool indicating hypervisor is not supported.

- qcom,fastrpc-adsp-audio-pdr		:	Flag to enable ADSP Audio PDR

- qcom,secure-domains		:	FastRPC secure domain configuration

- qcom,fastrpc-adsp-sensors-pdr		:	Flag to enable Sensors PDR

Optional subnodes:

- qcom,msm_fastrpc_compute_cb	:	Child nodes representing the compute context banks

- qcom,msm-fastrpc-rpmsg		:	Child node for rpmsg instead of glink for IPC

Subnode Required properties:

- compatible	:	Must be "qcom,msm-fastrpc-compute-cb"

- label			:	Label describing the channel this context bank belongs to

- iommus		:	A list of phandle and IOMMU specifier pairs that describe the

					IOMMU master interfaces of the device

- dma-coherent	:	A flag marking a context bank as I/O coherent

- shared-cb		:	A value indicating how many fastrpc sessions can share a

					context bank

Example:

	qcom,msm_fastrpc {

		compatible = "qcom,msm-fastrpc-compute";

		qcom,fastrpc-rpmsg;

		qcom,rpc-latency-us = <235>;

		qcom,adsp-remoteheap-vmid = <22 37>;

		qcom,fastrpc-adsp-sensors-pdr;

		qcom,msm_fastrpc_rpmsg {

			compatible = "qcom,msm-fastrpc-rpmsg";

			qcom,glink-channels = "fastrpcglink-apps-dsp";

			intents = <0x64 64>;

		};

		qcom,msm_fastrpc_compute_cb_1 {

			compatible = "qcom,msm-fastrpc-compute-cb";

			label = "cdsprpc-smd";

			qcom,secure-context-bank;

			iommus = <&apps_smmu 0x1401 0x0>;

			dma-coherent;

		};

		qcom,msm_fastrpc_compute_cb_2 {

			compatible = "qcom,msm-fastrpc-compute-cb";

			label = "sdsprpc-smd";

			iommus = <&apps_smmu 0x1402 0x0>;

			shared-cb = <5>;

		};

	};

Legacy SMMU v1/v2:

Required properties:

- compatible	:	Must be "qcom,msm-fastprc-legacy-compute-cb"

Required subnode:

- qcom,msm_fastrpc_compute_cb	:	Child nodes representing the compute context

									banks

Required subnode properties:

- qcom,adsp-shared-phandle	:	phandle that describe the context bank handle

- qcom,adsp-shared-sids		:	A list of SID associated with the context bank

- qcom,virtual-addr-pool	:	Virtual address range that the context bank

								will be using

Example:

        qcom,adsprpc_domains {

                compatible = "qcom,msm-fastrpc-legacy-compute-cb";

                qcom,msm_fastrpc_compute_cb {

                       qcom,adsp-shared-phandle = <&adsp_shared>;

                       qcom,adsp-shared-sids = <0x8 0x9>;

                       qcom,virtual-addr-pool = <0x80000000 0x7FFFFFFF>;

                };

        };

Remote Heap:

Required properties:

- compatible		:	Must be "qcom,msm-adsprpc-mem-region"

- memory-region		:	CMA region which is owned by this device

- restrict-access	:	Blocking vote for hyp_assign_phys function call

Example:

       qcom,adsprpc-mem {

               compatible = "qcom,msm-adsprpc-mem-region";

               memory-region = <&adsp_mem>;

               restrict-access;

       };