* Update Intel IXP4xx support

- Add IXP4xx NPE ethernet MAC support
- Add support for Intel IXDPG425 board
- Add support for Prodrive PDNB3 board
- Add IRQ support
Patch by Stefan Roese, 23 May 2006

[This patch does not include cpu/ixp/npe/IxNpeMicrocode.c which still
 sufferes from licensing issues. Blame Intel.]

1 files changed, 740 insertions, 0 deletions

diff --git a/cpu/ixp/npe/IxEthDBPortUpdate.c b/cpu/ixp/npe/IxEthDBPortUpdate.c
new file mode 100644
index 0000000..cdf114b
--- /dev/null
+++ b/cpu/ixp/npe/IxEthDBPortUpdate.c
@@ -0,0 +1,740 @@
+/**
+ * @file IxEthDBDBPortUpdate.c
+ *
+ * @brief Implementation of dependency and port update handling
+ * 
+ * @par
+ * IXP400 SW Release version 2.0
+ * 
+ * -- Copyright Notice --
+ * 
+ * @par
+ * Copyright 2001-2005, Intel Corporation.
+ * All rights reserved.
+ * 
+ * @par
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the Intel Corporation nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * 
+ * @par
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ * 
+ * @par
+ * -- End of Copyright Notice --
+ */
+
+#include "IxEthDB_p.h"
+
+/* forward prototype declarations */
+IX_ETH_DB_PRIVATE MacTreeNode* ixEthDBTreeInsert(MacTreeNode *searchTree, MacDescriptor *descriptor);
+IX_ETH_DB_PRIVATE void ixEthDBCreateTrees(IxEthDBPortMap updatePorts);
+IX_ETH_DB_PRIVATE MacTreeNode* ixEthDBTreeRebalance(MacTreeNode *searchTree);
+IX_ETH_DB_PRIVATE void ixEthDBRebalanceTreeToVine(MacTreeNode *root, UINT32 *size);
+IX_ETH_DB_PRIVATE void ixEthDBRebalanceVineToTree(MacTreeNode *root, UINT32 size);
+IX_ETH_DB_PRIVATE void ixEthDBRebalanceCompression(MacTreeNode *root, UINT32 count);
+IX_ETH_DB_PRIVATE UINT32 ixEthDBRebalanceLog2Floor(UINT32 x);
+
+extern HashTable dbHashtable;
+
+/**
+ * @brief register types requiring automatic updates
+ *
+ * @param typeArray array indexed on record types, each
+ * element indicating whether the record type requires an
+ * automatic update (TRUE) or not (FALSE)
+ * 
+ * Automatic updates are done for registered record types
+ * upon adding, updating (that is, updating the record portID) 
+ * and removing records. Whenever an automatic update is triggered
+ * the appropriate ports will be provided with new database
+ * information.
+ *
+ * It is assumed that the typeArray parameter is allocated large
+ * enough to hold all the user defined types. Also, the type
+ * array should be initialized to FALSE as this function only
+ * caters for types which do require automatic updates.
+ *
+ * Note that this function should be called by the component
+ * initialization function.
+ *
+ * @return number of record types registered for automatic
+ * updates
+ *
+ * @internal
+ */
+IX_ETH_DB_PUBLIC
+UINT32 ixEthDBUpdateTypeRegister(BOOL *typeArray)
+{
+    typeArray[IX_ETH_DB_FILTERING_RECORD]      = TRUE;
+    typeArray[IX_ETH_DB_FILTERING_VLAN_RECORD] = TRUE;
+
+    return 2;
+}
+
+/**
+ * @brief computes dependencies and triggers port learning tree updates
+ *
+ * @param triggerPorts port map consisting in the ports which triggered the update
+ *
+ * This function browses through all the ports and determines how to waterfall the update
+ * event from the trigger ports to all other ports depending on them.
+ *
+ * Once the list of ports to be updated is determined this function 
+ * calls @ref ixEthDBCreateTrees.
+ *
+ * @internal
+ */
+IX_ETH_DB_PUBLIC
+void ixEthDBUpdatePortLearningTrees(IxEthDBPortMap triggerPorts)
+{
+    IxEthDBPortMap updatePorts;
+    UINT32 portIndex;
+    
+    ixEthDBUpdateLock();
+    
+    SET_EMPTY_DEPENDENCY_MAP(updatePorts);
+    
+    for (portIndex = 0 ; portIndex < IX_ETH_DB_NUMBER_OF_PORTS ; portIndex++)
+    {
+        PortInfo *port   = &ixEthDBPortInfo[portIndex];
+        BOOL mapsCollide;
+        
+        MAPS_COLLIDE(mapsCollide, triggerPorts, port->dependencyPortMap);
+
+        if (mapsCollide                                   /* do triggers influence this port? */
+            && !IS_PORT_INCLUDED(portIndex, updatePorts)  /* and it's not already in the update list */
+            && port->updateMethod.updateEnabled)          /* and we're allowed to update it */
+        {
+            IX_ETH_DB_UPDATE_TRACE("DB: (Update) Adding port %d to update set\n", portIndex);
+
+            JOIN_PORT_TO_MAP(updatePorts, portIndex);
+        }
+        else
+        {
+            IX_ETH_DB_UPDATE_TRACE("DB: (Update) Didn't add port %d to update set, reasons follow:\n", portIndex);
+
+            if (!mapsCollide)
+            {
+                IX_ETH_DB_UPDATE_TRACE("\tMaps don't collide on port %d\n", portIndex);
+            }
+
+            if (IS_PORT_INCLUDED(portIndex, updatePorts))
+            {
+                IX_ETH_DB_UPDATE_TRACE("\tPort %d is already in the update set\n", portIndex);
+            }
+
+            if (!port->updateMethod.updateEnabled)
+            {
+                IX_ETH_DB_UPDATE_TRACE("\tPort %d doesn't have updateEnabled set\n", portIndex);
+            }
+        }
+    }
+    
+    IX_ETH_DB_UPDATE_TRACE("DB: (Update) Updating port set\n");
+
+    ixEthDBCreateTrees(updatePorts);
+        
+    ixEthDBUpdateUnlock();
+}
+
+/**
+ * @brief creates learning trees and calls the port update handlers
+ *
+ * @param updatePorts set of ports in need of learning trees
+ *
+ * This function determines the optimal method of creating learning
+ * trees using a minimal number of database queries, keeping in mind
+ * that different ports can either use the same learning trees or they
+ * can partially share them. The actual tree building routine is
+ * @ref ixEthDBQuery.
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+void ixEthDBCreateTrees(IxEthDBPortMap updatePorts)
+{
+    UINT32 portIndex;
+    BOOL result;
+    BOOL portsLeft = TRUE;
+
+    while (portsLeft)
+    {
+        /* get port with minimal dependency map and NULL search tree */
+        UINT32 minPortIndex = MAX_PORT_SIZE;
+        UINT32 minimalSize  = MAX_PORT_SIZE;
+
+        for (portIndex = 0 ; portIndex < IX_ETH_DB_NUMBER_OF_PORTS ; portIndex++)
+        {
+            UINT32 size;
+            PortInfo *port = &ixEthDBPortInfo[portIndex];
+
+            /* generate trees only for ports that need them */
+            if (!port->updateMethod.searchTreePendingWrite && IS_PORT_INCLUDED(portIndex, updatePorts))
+            {
+                GET_MAP_SIZE(port->dependencyPortMap, size);
+                
+                IX_ETH_DB_UPDATE_TRACE("DB: (Update) Dependency map for port %d: size %d\n",
+                    portIndex, size);
+
+                if (size < minimalSize)
+                {
+                    minPortIndex = portIndex;
+                    minimalSize  = size;
+                }
+            }
+            else
+            {
+                IX_ETH_DB_UPDATE_TRACE("DB: (Update) Skipped port %d from tree diff (%s)\n", portIndex,
+                    port->updateMethod.searchTreePendingWrite ? "pending write access" : "ignored by query");
+            }            
+        }
+
+        /* if a port was found than minimalSize is not MAX_PORT_SIZE */
+        if (minimalSize != MAX_PORT_SIZE)
+        {
+            /* minPortIndex is the port we seek */
+            PortInfo *port = &ixEthDBPortInfo[minPortIndex];
+
+            IxEthDBPortMap query;
+            MacTreeNode *baseTree;
+
+            /* now try to find a port with minimal map difference */
+            PortInfo *minimalDiffPort = NULL;
+            UINT32 minimalDiff        = MAX_PORT_SIZE;
+            
+            IX_ETH_DB_UPDATE_TRACE("DB: (Update) Minimal size port is %d\n", minPortIndex);
+
+            for (portIndex = 0 ; portIndex < IX_ETH_DB_NUMBER_OF_PORTS ; portIndex++)
+            {   
+                PortInfo *diffPort = &ixEthDBPortInfo[portIndex];
+                BOOL mapIsSubset;
+                
+                IS_MAP_SUBSET(mapIsSubset, diffPort->dependencyPortMap, port->dependencyPortMap);
+                
+
+                if (portIndex != minPortIndex
+                    && diffPort->updateMethod.searchTree != NULL
+                    && mapIsSubset)
+                {
+                    /* compute size and pick only minimal size difference */
+                    UINT32 diffPortSize;
+                    UINT32 sizeDifference;
+
+                    GET_MAP_SIZE(diffPort->dependencyPortMap, diffPortSize);
+                     
+                    IX_ETH_DB_UPDATE_TRACE("DB: (Update) Checking port %d for differences...\n", portIndex);
+
+                    sizeDifference = minimalSize - diffPortSize;
+
+                    if (sizeDifference < minimalDiff)
+                    {
+                        minimalDiffPort = diffPort;
+                        minimalDiff     = sizeDifference;
+                        
+                        IX_ETH_DB_UPDATE_TRACE("DB: (Update) Minimal difference 0x%x was found on port %d\n",
+                            minimalDiff, portIndex);
+                    }
+                }
+            }
+
+            /* check if filtering is enabled on this port */
+            if ((port->featureStatus & IX_ETH_DB_FILTERING) != 0)
+            {
+                /* if minimalDiff is not MAX_PORT_SIZE minimalDiffPort points to the most similar port */
+                if (minimalDiff != MAX_PORT_SIZE)
+                {
+                    baseTree = ixEthDBCloneMacTreeNode(minimalDiffPort->updateMethod.searchTree);
+                    DIFF_MAPS(query, port->dependencyPortMap , minimalDiffPort->dependencyPortMap);
+                    
+                    IX_ETH_DB_UPDATE_TRACE("DB: (Update) Found minimal diff, extending tree %d on query\n",
+                        minimalDiffPort->portID);
+                }
+                else /* .. otherwise no similar port was found, build tree from scratch */
+                {
+                    baseTree = NULL;
+                    
+                    COPY_DEPENDENCY_MAP(query, port->dependencyPortMap);
+                    
+                    IX_ETH_DB_UPDATE_TRACE("DB: (Update) No similar diff, creating tree from query\n");
+                }
+
+                IS_EMPTY_DEPENDENCY_MAP(result, query);
+                
+                if (!result) /* otherwise we don't need anything more on top of the cloned tree */
+                {
+                    IX_ETH_DB_UPDATE_TRACE("DB: (Update) Adding query tree to port %d\n", minPortIndex);
+                        
+                    /* build learning tree */
+                    port->updateMethod.searchTree = ixEthDBQuery(baseTree, query, IX_ETH_DB_ALL_FILTERING_RECORDS, MAX_ELT_SIZE);
+                }
+                else
+                {
+                    IX_ETH_DB_UPDATE_TRACE("DB: (Update) Query is empty, assuming identical nearest tree\n");
+                      
+                    port->updateMethod.searchTree = baseTree;
+                }
+            }
+            else
+            {
+                /* filtering is not enabled, will download an empty tree */
+                if (port->updateMethod.searchTree != NULL)
+                {
+                    ixEthDBFreeMacTreeNode(port->updateMethod.searchTree);
+                }
+
+                port->updateMethod.searchTree = NULL;
+            }
+
+            /* mark tree as valid */
+            port->updateMethod.searchTreePendingWrite = TRUE;
+        }
+        else
+        {
+            portsLeft = FALSE;
+
+            IX_ETH_DB_UPDATE_TRACE("DB: (Update) No trees to create this round\n");            
+        }
+    }
+    
+    for (portIndex = 0 ; portIndex < IX_ETH_DB_NUMBER_OF_PORTS ; portIndex++)
+    {
+        PortInfo *updatePort = &ixEthDBPortInfo[portIndex];
+
+        if (updatePort->updateMethod.searchTreePendingWrite)
+        {
+            IX_ETH_DB_UPDATE_TRACE("DB: (PortUpdate) Starting procedure to upload new search tree (%snull) into NPE %d\n", 
+                updatePort->updateMethod.searchTree != NULL ? "not " : "",
+                portIndex);
+
+            updatePort->updateMethod.updateHandler(portIndex, IX_ETH_DB_FILTERING_RECORD);
+        }
+    }
+}
+
+/**
+ * @brief standard NPE update handler
+ *
+ * @param portID id of the port to be updated
+ * @param type record type to be pushed during this update
+ *
+ * The NPE update handler manages updating the NPE databases
+ * given a certain record type.
+ *
+ * @internal
+ */
+IX_ETH_DB_PUBLIC
+IxEthDBStatus ixEthDBNPEUpdateHandler(IxEthDBPortId portID, IxEthDBRecordType type)
+{
+    UINT32 epDelta, blockCount;
+    IxNpeMhMessage message;
+    UINT32 treeSize = 0;
+    PortInfo *port = &ixEthDBPortInfo[portID];
+
+    /* size selection and type check */
+    if (type == IX_ETH_DB_FILTERING_RECORD || type == IX_ETH_DB_WIFI_RECORD)
+    {
+        treeSize = FULL_ELT_BYTE_SIZE;
+    }
+    else if (type == IX_ETH_DB_FIREWALL_RECORD)
+    {
+        treeSize = FULL_FW_BYTE_SIZE;
+    }
+    else
+    {
+        return IX_ETH_DB_INVALID_ARG;
+    }
+    
+    /* serialize tree into memory */
+    ixEthDBNPETreeWrite(type, treeSize, port->updateMethod.npeUpdateZone, port->updateMethod.searchTree, &epDelta, &blockCount);
+
+    /* free internal copy */
+    if (port->updateMethod.searchTree != NULL)
+    {
+        ixEthDBFreeMacTreeNode(port->updateMethod.searchTree);
+    }
+
+    /* forget last used search tree */
+    port->updateMethod.searchTree             = NULL;
+    port->updateMethod.searchTreePendingWrite = FALSE;
+
+    /* dependending on the update type we do different things */
+    if (type == IX_ETH_DB_FILTERING_RECORD || type == IX_ETH_DB_WIFI_RECORD)
+    {
+        IX_STATUS result;
+
+        FILL_SETMACADDRESSDATABASE_MSG(message, IX_ETH_DB_PORT_ID_TO_NPE_LOGICAL_ID(portID), 
+            epDelta, blockCount, 
+            IX_OSAL_MMU_VIRT_TO_PHYS(port->updateMethod.npeUpdateZone));
+
+        IX_ETHDB_SEND_NPE_MSG(IX_ETH_DB_PORT_ID_TO_NPE(portID), message, result);
+
+        if (result == IX_SUCCESS)
+	{
+            IX_ETH_DB_UPDATE_TRACE("DB: (PortUpdate) Finished downloading NPE tree on port %d\n", portID);
+        }
+        else
+        {
+            ixEthDBPortInfo[portID].agingEnabled                = FALSE;
+            ixEthDBPortInfo[portID].updateMethod.updateEnabled  = FALSE;
+            ixEthDBPortInfo[portID].updateMethod.userControlled = TRUE;
+
+            ERROR_LOG("EthDB: (PortUpdate) disabling aging and updates on port %d (assumed dead)\n", portID);
+
+            ixEthDBDatabaseClear(portID, IX_ETH_DB_ALL_RECORD_TYPES);
+
+            return IX_ETH_DB_FAIL;
+        }
+
+	return IX_ETH_DB_SUCCESS;
+    }
+    else if (type == IX_ETH_DB_FIREWALL_RECORD)
+    {
+        return ixEthDBFirewallUpdate(portID, port->updateMethod.npeUpdateZone, epDelta);
+    }
+    
+    return IX_ETH_DB_INVALID_ARG;
+}
+
+/**
+ * @brief queries the database for a set of records to be inserted into a given tree
+ *
+ * @param searchTree pointer to a tree where insertions will be performed; can be NULL
+ * @param query set of ports that a database record must match to be inserted into the tree
+ *
+ * The query method browses through the database, extracts all the descriptors matching
+ * the given query parameter and inserts them into the given learning tree.
+ * Note that this is an append procedure, the given tree needs not to be empty.
+ * A "descriptor matching the query" is a descriptor whose port id is in the query map.
+ * If the given tree is empty (NULL) a new tree is created and returned.
+ * 
+ * @return the tree root
+ *
+ * @internal
+ */
+IX_ETH_DB_PUBLIC
+MacTreeNode* ixEthDBQuery(MacTreeNode *searchTree, IxEthDBPortMap query, IxEthDBRecordType recordFilter, UINT32 maxEntries)
+{
+    HashIterator iterator;
+    UINT32 entryCount = 0;
+
+    /* browse database */
+    BUSY_RETRY(ixEthDBInitHashIterator(&dbHashtable, &iterator));
+
+    while (IS_ITERATOR_VALID(&iterator))
+    {
+        MacDescriptor *descriptor = (MacDescriptor *) iterator.node->data;
+
+        IX_ETH_DB_UPDATE_TRACE("DB: (PortUpdate) querying [%s]:%d on port map ... ", 
+            mac2string(descriptor->macAddress), 
+            descriptor->portID);
+
+	if ((descriptor->type & recordFilter) != 0 
+            && IS_PORT_INCLUDED(descriptor->portID, query))
+	{
+            MacDescriptor *descriptorClone = ixEthDBCloneMacDescriptor(descriptor);
+
+            IX_ETH_DB_UPDATE_TRACE("match\n");
+
+            if (descriptorClone != NULL)
+            {
+                /* add descriptor to tree */
+                searchTree = ixEthDBTreeInsert(searchTree, descriptorClone);
+
+                entryCount++;
+            }
+        }
+        else
+        {
+            IX_ETH_DB_UPDATE_TRACE("no match\n");
+        }
+
+        if (entryCount < maxEntries)
+        {
+            /* advance to the next record */
+	        BUSY_RETRY(ixEthDBIncrementHashIterator(&dbHashtable, &iterator));
+        }
+        else
+        {
+            /* the NPE won't accept more entries so we can stop now */
+            ixEthDBReleaseHashIterator(&iterator);
+
+            IX_ETH_DB_UPDATE_TRACE("DB: (PortUpdate) number of elements reached maximum supported by port\n");
+
+            break;
+        }
+    }
+
+    IX_ETH_DB_UPDATE_TRACE("DB: (PortUpdate) query inserted %d records in the search tree\n", entryCount);
+
+    return ixEthDBTreeRebalance(searchTree);
+}
+
+/**
+ * @brief inserts a mac descriptor into an tree
+ *
+ * @param searchTree tree where the insertion is to be performed (may be NULL)
+ * @param descriptor descriptor to insert into tree
+ *
+ * @return the tree root
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+MacTreeNode* ixEthDBTreeInsert(MacTreeNode *searchTree, MacDescriptor *descriptor)
+{
+    MacTreeNode *currentNode    = searchTree;
+    MacTreeNode *insertLocation = NULL;
+    MacTreeNode *newNode;
+    INT32 insertPosition = RIGHT;
+
+    if (descriptor == NULL)
+    {
+        return searchTree;
+    }
+
+    /* create a new node */
+    newNode = ixEthDBAllocMacTreeNode();
+
+    if (newNode == NULL)
+    {
+        /* out of memory */
+        ERROR_LOG("Warning: ixEthDBAllocMacTreeNode returned NULL in file %s:%d (out of memory?)\n", __FILE__, __LINE__);
+
+        ixEthDBFreeMacDescriptor(descriptor);
+
+        return NULL;
+    }
+
+    /* populate node */
+    newNode->descriptor = descriptor;
+
+    /* an empty initial tree is a special case */
+    if (searchTree == NULL)
+    {
+        return newNode;
+    }
+
+    /* get insertion location */
+    while (insertLocation == NULL)
+    {
+        MacTreeNode *nextNode;
+
+        /* compare given key with current node key */
+        insertPosition = ixEthDBAddressCompare(descriptor->macAddress, currentNode->descriptor->macAddress);
+
+        /* navigate down */
+        if (insertPosition == RIGHT)
+        {
+            nextNode = currentNode->right;
+        }
+        else if (insertPosition == LEFT)
+        {
+            nextNode = currentNode->left;
+        }
+        else
+        {
+            /* error, duplicate key */
+            ERROR_LOG("Warning: trapped insertion of a duplicate MAC address in an NPE search tree\n");
+
+            /* this will free the MAC descriptor as well */
+            ixEthDBFreeMacTreeNode(newNode);
+
+            return searchTree;
+        }
+
+        /* when we can no longer dive through the tree we found the insertion place */
+        if (nextNode != NULL)
+        {
+            currentNode = nextNode;
+        }
+        else
+        {
+            insertLocation = currentNode;
+        }
+    }
+
+    /* insert node */
+    if (insertPosition == RIGHT)
+    {
+        insertLocation->right = newNode;
+    }
+    else
+    {
+        insertLocation->left = newNode;
+    }
+
+    return searchTree;
+}
+
+/**
+ * @brief balance a tree
+ *
+ * @param searchTree tree to balance
+ *
+ * Converts a tree into a balanced tree and returns the root of
+ * the balanced tree. The resulting tree is <i>route balanced</i>
+ * not <i>perfectly balanced</i>. This makes no difference to the
+ * average tree search time which is the same in both cases, O(log2(n)).
+ *
+ * @return root of the balanced tree or NULL if there's no memory left
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+MacTreeNode* ixEthDBTreeRebalance(MacTreeNode *searchTree)
+{
+    MacTreeNode *pseudoRoot = ixEthDBAllocMacTreeNode();
+    UINT32 size;
+
+    if (pseudoRoot == NULL)
+    {
+        /* out of memory */
+        return NULL;
+    }
+
+    pseudoRoot->right = searchTree;
+
+    ixEthDBRebalanceTreeToVine(pseudoRoot, &size);
+    ixEthDBRebalanceVineToTree(pseudoRoot, size);
+
+    searchTree = pseudoRoot->right;
+
+    /* remove pseudoRoot right branch, otherwise it will free the entire tree */
+    pseudoRoot->right = NULL;
+
+    ixEthDBFreeMacTreeNode(pseudoRoot);
+
+    return searchTree;
+}
+
+/**
+ * @brief converts a tree into a vine
+ *
+ * @param root root of tree to convert
+ * @param size depth of vine (equal to the number of nodes in the tree)
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+void ixEthDBRebalanceTreeToVine(MacTreeNode *root, UINT32 *size)
+{
+    MacTreeNode *vineTail  = root;
+    MacTreeNode *remainder = vineTail->right;
+    MacTreeNode *tempPtr;
+
+    *size = 0;
+
+    while (remainder != NULL)
+    {
+        if (remainder->left == NULL)
+        {
+            /* move tail down one */
+            vineTail  = remainder;
+            remainder = remainder->right;
+            (*size)++;
+        }
+        else
+        {
+            /* rotate around remainder */
+            tempPtr         = remainder->left;
+            remainder->left = tempPtr->right;
+            tempPtr->right  = remainder;
+            remainder       = tempPtr;
+            vineTail->right = tempPtr;
+        }
+    }
+}
+
+/**
+ * @brief converts a vine into a balanced tree
+ *
+ * @param root vine to convert
+ * @param size depth of vine
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+void ixEthDBRebalanceVineToTree(MacTreeNode *root, UINT32 size)
+{
+    UINT32 leafCount = size + 1 - (1 << ixEthDBRebalanceLog2Floor(size + 1));
+
+    ixEthDBRebalanceCompression(root, leafCount);
+
+    size = size - leafCount;
+
+    while (size > 1)
+    {
+        ixEthDBRebalanceCompression(root, size / 2);
+
+        size /= 2;
+    }
+}
+
+/**
+ * @brief compresses a vine/tree stage into a more balanced vine/tree
+ *
+ * @param root root of the tree to compress
+ * @param count number of "spine" nodes
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+void ixEthDBRebalanceCompression(MacTreeNode *root, UINT32 count)
+{
+    MacTreeNode *scanner = root;
+    MacTreeNode *child;
+    UINT32 local_index;
+
+    for (local_index = 0 ; local_index < count ; local_index++)
+    {
+        child          = scanner->right;
+        scanner->right = child->right;
+        scanner        = scanner->right;
+        child->right   = scanner->left;
+        scanner->left  = child;
+    }
+}
+
+/**
+ * @brief computes |_log2(x)_| (a.k.a. floor(log2(x)))
+ *
+ * @param x number to compute |_log2(x)_| for
+ *
+ * @return |_log2(x)_|
+ *
+ * @internal
+ */
+IX_ETH_DB_PRIVATE
+UINT32 ixEthDBRebalanceLog2Floor(UINT32 x)
+{
+    UINT32 log = 0;
+    UINT32 val = 1;
+
+    while (val < x)
+    {
+        log++;
+        val <<= 1;
+    }
+
+    return val == x ? log : log - 1;
+}
+