VOL-4274 Move platform.go file to voltha-lib-go
This file exists both in olt-adapter and onu-adapter with duplicate constants and functions.
Becaues it includes constants and functions that can be used by any VOLTHA component,
it is more convenient to move it to voltha-lib. Adapters will be changed after lib is merged.

Change-Id: Idd51947d7efcfd28ebaa2e6e1da07a79e3091f45
diff --git a/pkg/platform/platform.go b/pkg/platform/platform.go
new file mode 100644
index 0000000..470d4a9
--- /dev/null
+++ b/pkg/platform/platform.go
@@ -0,0 +1,271 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package platform
+
+import (
+	"context"
+
+	"github.com/opencord/voltha-lib-go/v7/pkg/flows"
+	"github.com/opencord/voltha-lib-go/v7/pkg/log"
+	ofp "github.com/opencord/voltha-protos/v5/go/openflow_13"
+	"github.com/opencord/voltha-protos/v5/go/voltha"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+/*=====================================================================
+Logical (OF) UNI port number
+
+    OpenFlow port number corresponding to PON UNI
+
+     20        12              4      0
+    +--+--------+--------------+------+
+    |0 | pon id |    onu id    |uni id|
+    +--+--------+--------------+------+
+
+    pon id = 8 bits = 256 PON ports
+    onu id = 8 bits = 256 ONUs per PON port
+
+Logical (OF) NNI port number
+
+    OpenFlow port number corresponding to PON NNI
+
+     20                             0
+    +--+----------------------------+
+    |1 |                    intf_id |
+    +--+----------------------------+
+
+    No overlap with UNI port number space
+
+
+PON OLT (OF) port number
+
+    OpenFlow port number corresponding to PON OLT ports
+
+     31     28                                 0
+    +--------+------------------------~~~------+
+    |  0x2   |          pon intf id            |
+    +--------+------------------------~~~------+
+*/
+
+const (
+	// Number of bits for the physical UNI of the ONUs
+	bitsForUniID = 4
+	// Number of bits for the ONU ID
+	bitsForONUID = 8
+	// Number of bits for PON ID
+	bitsForPONID = 8
+	// MaxOnusPerPon is Max number of ONUs on any PON port
+	MaxOnusPerPon = (1 << bitsForONUID)
+	// MaxPonsPerOlt is Max number of PON ports on any OLT
+	MaxPonsPerOlt = (1 << bitsForPONID)
+	// MaxUnisPerOnu is the Max number of UNI ports on any ONU
+	MaxUnisPerOnu = (1 << bitsForUniID)
+	// Bit position where the differentiation bit is located
+	nniUniDiffPos = (bitsForUniID + bitsForONUID + bitsForPONID)
+	// Bit position where the marker for PON port type of OF port is present
+	ponIntfMarkerPos = 28
+	// Value of marker used to distinguish PON port type of OF port
+	ponIntfMarkerValue = 0x2
+	// Number of bits for NNI ID
+	bitsforNNIID = 20
+	// minNniIntPortNum is used to store start range of nni port number (1 << 20) 1048576
+	minNniIntPortNum = (1 << bitsforNNIID)
+	// maxNniPortNum is used to store the maximum range of nni port number ((1 << 21)-1) 2097151
+	maxNniPortNum = ((1 << (bitsforNNIID + 1)) - 1)
+	// minPonIntfPortNum stores the minimum pon port number
+	minPonIntfPortNum = ponIntfMarkerValue << ponIntfMarkerPos
+	// maxPonIntfPortNum stores the maximum pon port number
+	maxPonIntfPortNum = (ponIntfMarkerValue << ponIntfMarkerPos) | (1 << bitsForPONID)
+	upstream          = "upstream"
+	downstream        = "downstream"
+)
+
+//MinUpstreamPortID value
+var MinUpstreamPortID = 0xfffd
+
+//MaxUpstreamPortID value
+var MaxUpstreamPortID = 0xfffffffd
+
+var controllerPorts = []uint32{0xfffd, 0x7ffffffd, 0xfffffffd}
+
+//MkUniPortNum returns new UNIportNum based on intfID, inuID and uniID
+func MkUniPortNum(ctx context.Context, intfID, onuID, uniID uint32) uint32 {
+	var limit = int(onuID)
+	if limit > MaxOnusPerPon {
+		logger.Warn(ctx, "exceeded-the-max-onus-per-pon")
+	}
+	return (intfID << (bitsForUniID + bitsForONUID)) | (onuID << bitsForUniID) | uniID
+}
+
+//OnuIDFromPortNum returns ONUID derived from portNumber
+func OnuIDFromPortNum(portNum uint32) uint32 {
+	return (portNum >> bitsForUniID) & (MaxOnusPerPon - 1)
+}
+
+//IntfIDFromUniPortNum returns IntfID derived from portNum
+func IntfIDFromUniPortNum(portNum uint32) uint32 {
+	return (portNum >> (bitsForUniID + bitsForONUID)) & (MaxPonsPerOlt - 1)
+}
+
+//UniIDFromPortNum return UniID derived from portNum
+func UniIDFromPortNum(portNum uint32) uint32 {
+	return (portNum) & (MaxUnisPerOnu - 1)
+}
+
+//IntfIDToPortNo returns portId derived from intftype, intfId and portType
+func IntfIDToPortNo(intfID uint32, intfType voltha.Port_PortType) uint32 {
+	if (intfType) == voltha.Port_ETHERNET_NNI {
+		return (1 << nniUniDiffPos) | intfID
+	}
+	if (intfType) == voltha.Port_PON_OLT {
+		return (ponIntfMarkerValue << ponIntfMarkerPos) | intfID
+	}
+	return 0
+}
+
+//PortNoToIntfID returns portnumber derived from interfaceID
+func PortNoToIntfID(portno uint32, intfType voltha.Port_PortType) uint32 {
+	if (intfType) == voltha.Port_ETHERNET_NNI {
+		return (1 << nniUniDiffPos) ^ portno
+	}
+	if (intfType) == voltha.Port_PON_OLT {
+		return (ponIntfMarkerValue << ponIntfMarkerPos) ^ portno
+	}
+	return 0
+}
+
+//IntfIDFromNniPortNum returns Intf ID derived from portNum
+func IntfIDFromNniPortNum(ctx context.Context, portNum uint32) (uint32, error) {
+	if portNum < minNniIntPortNum || portNum > maxNniPortNum {
+		logger.Errorw(ctx, "nniportnumber-is-not-in-valid-range", log.Fields{"portnum": portNum})
+		return uint32(0), status.Errorf(codes.InvalidArgument, "nni-port-number-out-of-range:%d", portNum)
+	}
+	return (portNum & 0xFFFF), nil
+}
+
+//IntfIDFromPonPortNum returns Intf ID derived from portNum
+func IntfIDFromPonPortNum(ctx context.Context, portNum uint32) (uint32, error) {
+	if portNum < minPonIntfPortNum || portNum > maxPonIntfPortNum {
+		logger.Errorw(ctx, "ponportnumber-is-not-in-valid-range", log.Fields{"portnum": portNum})
+		return uint32(0), status.Errorf(codes.InvalidArgument, "invalid-pon-port-number:%d", portNum)
+	}
+	return (portNum & 0x7FFF), nil
+}
+
+//IntfIDToPortTypeName returns port type derived from the intfId
+func IntfIDToPortTypeName(intfID uint32) voltha.Port_PortType {
+	if ((ponIntfMarkerValue << ponIntfMarkerPos) ^ intfID) < MaxPonsPerOlt {
+		return voltha.Port_PON_OLT
+	}
+	if (intfID & (1 << nniUniDiffPos)) == (1 << nniUniDiffPos) {
+		return voltha.Port_ETHERNET_NNI
+	}
+	return voltha.Port_ETHERNET_UNI
+}
+
+//ExtractAccessFromFlow returns AccessDevice information
+func ExtractAccessFromFlow(inPort, outPort uint32) (uint32, uint32, uint32, uint32) {
+	if IsUpstream(outPort) {
+		return inPort, IntfIDFromUniPortNum(inPort), OnuIDFromPortNum(inPort), UniIDFromPortNum(inPort)
+	}
+	return outPort, IntfIDFromUniPortNum(outPort), OnuIDFromPortNum(outPort), UniIDFromPortNum(outPort)
+}
+
+//IsUpstream returns true for Upstream and false for downstream
+func IsUpstream(outPort uint32) bool {
+	for _, port := range controllerPorts {
+		if port == outPort {
+			return true
+		}
+	}
+	return (outPort & (1 << nniUniDiffPos)) == (1 << nniUniDiffPos)
+}
+
+//IsControllerBoundFlow returns true/false
+func IsControllerBoundFlow(outPort uint32) bool {
+	for _, port := range controllerPorts {
+		if port == outPort {
+			return true
+		}
+	}
+	return false
+}
+
+//OnuIDFromUniPortNum returns onuId from give portNum information.
+func OnuIDFromUniPortNum(portNum uint32) uint32 {
+	return (portNum >> bitsForUniID) & (MaxOnusPerPon - 1)
+}
+
+//FlowExtractInfo fetches uniport from the flow, based on which it gets and returns ponInf, onuID, uniID, inPort and ethType
+func FlowExtractInfo(ctx context.Context, flow *ofp.OfpFlowStats, flowDirection string) (uint32, uint32, uint32, uint32, uint32, uint32, error) {
+	var uniPortNo uint32
+	var ponIntf uint32
+	var onuID uint32
+	var uniID uint32
+	var inPort uint32
+	var ethType uint32
+
+	if flowDirection == upstream {
+		if uniPortNo = flows.GetChildPortFromTunnelId(flow); uniPortNo == 0 {
+			for _, field := range flows.GetOfbFields(flow) {
+				if field.GetType() == flows.IN_PORT {
+					uniPortNo = field.GetPort()
+					break
+				}
+			}
+		}
+	} else if flowDirection == downstream {
+		if uniPortNo = flows.GetChildPortFromTunnelId(flow); uniPortNo == 0 {
+			for _, field := range flows.GetOfbFields(flow) {
+				if field.GetType() == flows.METADATA {
+					for _, action := range flows.GetActions(flow) {
+						if action.Type == flows.OUTPUT {
+							if out := action.GetOutput(); out != nil {
+								uniPortNo = out.GetPort()
+							}
+							break
+						}
+					}
+				} else if field.GetType() == flows.IN_PORT {
+					inPort = field.GetPort()
+				} else if field.GetType() == flows.ETH_TYPE {
+					ethType = field.GetEthType()
+				}
+			}
+		}
+	}
+
+	if uniPortNo == 0 {
+		return 0, 0, 0, 0, 0, 0, status.Errorf(codes.NotFound, "uni-not-found-flow-diraction:%s", flowDirection)
+	}
+
+	ponIntf = IntfIDFromUniPortNum(uniPortNo)
+	onuID = OnuIDFromUniPortNum(uniPortNo)
+	uniID = UniIDFromPortNum(uniPortNo)
+
+	logger.Debugw(ctx, "flow-extract-info-result",
+		log.Fields{
+			"uniportno": uniPortNo,
+			"pon-intf":  ponIntf,
+			"onu-id":    onuID,
+			"uni-id":    uniID,
+			"inport":    inPort,
+			"ethtype":   ethType})
+
+	return uniPortNo, ponIntf, onuID, uniID, inPort, ethType, nil
+}