Documentation/devicetree/bindings/media/video/msm-cam-smmu.txt

* Qualcomm Technologies, Inc. MSM Camera SMMU

The MSM camera SMMU device provides SMMU context bank definitions
for all HW blocks that need to map IOVA to physical memory. These
definitions consist of various properties that define how the
IOVA address space is laid out for each HW block in the camera
subsystem.

=======================
Required Node Structure
=======================
The camera SMMU device must be described in three levels of device nodes. The
first level describes the overall SMMU device. Within it, second level nodes
describe individual context banks that map different stream ids. There can
also be second level nodes describing firmware device nodes. Each HW block
such as IFE, ICP maps into these second level device nodes. All context bank
specific properties that define how the IOVA is laid out is contained within
third level device nodes within the second level device nodes.

During the kernel initialization all the devices are probed recursively and
a device pointer is created for each context bank keeping track of the IOVA
mapping information.

Duplicate regions of the same type are not allowed within the same
context bank. All context banks must contain an IO region at the very least.

==================================
First Level Node - CAM SMMU device
==================================
- compatible
  Usage: required
  Value type: <string>
  Definition: Should be "qcom,msm-cam-smmu".

===================================================================
Second Level Node - CAM SMMU context bank device or firmware device
===================================================================
- compatible
  Usage: required
  Value type: <string>
  Definition: Should be "qcom,msm-cam-smmu-cb" or "qcom,msm-cam-smmu-fw-dev".

- memory-region
  Usage: optional
  Value type: <phandle>
  Definition: Should specify the phandle of the memory region for firmware.
    allocation

- iommus
  Usage: required
  Value type: <phandle>
  Definition: Should specify the phandle of the iommu sid.

- label
  Usage: required
  Value type: <string>
  Definition: Should specify a string label to identify the context bank.

=============================================
Third Level Node - CAM SMMU memory map device
=============================================
- iova-region-name
  Usage: required
  Value type: <string>
  Definition: Should specify a string label to identify the IOVA region.

- iova-region-start
  Usage: required
  Value type: <u32>
  Definition: Should specify start IOVA for region.

- iova-region-len
  Usage: required
  Value type: <u32>
  Definition: Should specify length for IOVA region.

- iova-region-id
  Usage: required
  Value type: <u32>
  Definition: Should specify the numerical identifier for IOVA region.
    Allowed values are: 0x00 to 0x03
      - Firmware region: 0x00
      - Shared region: 0x01
      - Scratch region: 0x02
      - IO region: 0x03

Example:
	qcom,cam_smmu@0 {
		compatible = "qcom,msm-cam-smmu";

		msm_cam_smmu_icp {
			compatible = "qcom,msm-cam-smmu-cb";
			iommus = <&apps_smmu 0x1078>,
				<&apps_smmu 0x1020>,
				<&apps_smmu 0x1028>,
				<&apps_smmu 0x1040>,
				<&apps_smmu 0x1048>,
				<&apps_smmu 0x1030>,
				<&apps_smmu 0x1050>;
			label = "icp";
			icp_iova_mem_map: iova-mem-map {
				iova-mem-region-firmware {
					/* Firmware region is 5MB */
				        iova-region-name = "firmware";
				        iova-region-start = <0x0>;
				        iova-region-len = <0x500000>;
					iova-region-id = <0x0>;
					status = "ok";
				};

			        iova-mem-region-shared {
					/* Shared region is 100MB long */
				        iova-region-name = "shared";
				        iova-region-start = <0x7400000>;
				        iova-region-len = <0x6400000>;
					iova-region-id = <0x1>;
				        status = "ok";
				};

			        iova-mem-region-io {
				        /* IO region is approximately 3.5 GB */
				        iova-region-name = "io";
					iova-region-start = <0xd800000>;
				        iova-region-len = <0xd2800000>;
				        iova-region-id = <0x3>;
				        status = "ok";
				};
			};
		};
	};