Qualcomm Technologies Inc MHI Bus controller

MHI control driver enables clients to communicate with external mode
using MHI protocol.

==============
Node Structure
==============

Main node properties:

- reg
  Usage: required
  Value type: Array (5-cell PCI resource) of <u32>
  Definition: First cell is devfn, which is determined by pci bus topology.
	Assign the other cells 0 since they are not used.

- qcom,smmu-cfg
  Usage: required
  Value type: <u32>
  Definition: Required SMMU configuration bitmask for PCIe bus.
	BIT mask:
	BIT(0) : Attach address mapping to endpoint device
	BIT(1) : Set attribute S1_BYPASS
	BIT(2) : Set attribute FAST
	BIT(3) : Set attribute ATOMIC
	BIT(4) : Set attribute FORCE_COHERENT

- qcom,addr-win
  Usage: required if SMMU S1 translation is enabled
  Value type: Array of <u64>
  Definition: Pair of values describing iova start and stop address

- qcom,msm-bus,name
  Usage: required if bus scale used
  Value type: <string>
  Definition: string representing the bus scale client name to register if
	bus scale voting is supported and required.

- qcom,msm-bus,num-cases
  Usage: required if bus scale used
  Value type: <u32>
  Definition: Must be set to two, MHI support two scales

- qcom,msm-bus,num-paths
  Usage: required if bus scale used
  Value type: <u32>
  Definition: Total number of master-slave pairs MHI host will vote. Must be set
	to one.

- qcom,msm-bus,vectors-KBps
  Usage: required if bus scale used
  Value type: Array of <u32>
  Definition: Array of tuples which define the bus bandwidth requirements.
	Each tuple is of length 4, values are master-id, slave-id,
	arbitrated bandwidth in KBps, and instantaneous bandwidth in
	KBps.

- esoc-names
  Usage: optional
  Value type: <string>
  Definition: if external modem managed by esoc framework, set string to "mdm"

- esoc-0
  Usage: required if device is managed by esoc framework
  Value type: phandle
  Definition: A esoc phandle pointing to external modem

- MHI bus settings
  Usage: required
  Values: as defined by mhi.txt
  Definition: Per definition of devicetree/bindings/bus/mhi.txt, define device
	specific MHI configuration parameters.

========
Example:
========

/* pcie domain (root complex) modem connected to */
&pcie1 {
	/* pcie bus modem connected to */
	pci,bus@1 {
		reg = <0 0 0 0 0>;

		qcom,mhi {
			reg = <0 0 0 0 0>;
			qcom,smmu-cfg = <0x3d>;
			qcom,addr-win = <0x0 0x20000000 0x0 0x3fffffff>;
			qcom,msm-bus,name = "mhi";
			qcom,msm-bus,num-cases = <2>;
			qcom,msm-bus,num-paths = <1>;
			qcom,msm-bus,vectors-KBps = <45 512 0 0>,
				<45 512 1200000000 650000000>;

			<mhi bus configurations>
		};
	};
};