don't make HTIF clock divider tied to backup memory

src/main/scala/Configs.scala

@@ -228,7 +228,8 @@ class DefaultConfig extends Config (
       case BankIdLSB => 0
       case CacheBlockBytes => Dump("CACHE_BLOCK_BYTES", 64)
       case CacheBlockOffsetBits => log2Up(here(CacheBlockBytes))
-      case UseBackupMemoryPort => true
+      case UseBackupMemoryPort => false
+      case UseHtifClockDiv => true
       case MMIOBase => Dump("MEM_SIZE", BigInt(1L << 30)) // 1 GB
       case DeviceTree => makeDeviceTree()
       case GlobalAddrMap => {
@@ -356,7 +357,7 @@ class ZscaleConfig extends Config(new WithZscale ++ new DefaultConfig)
 class FPGAConfig extends Config (
   (pname,site,here) => pname match {
     case NAcquireTransactors => 4
-    case UseBackupMemoryPort => false
+    case UseHtifClockDiv => false
   }
 )
 

src/main/scala/RocketChip.scala

@@ -27,6 +27,8 @@ case object BankIdLSB extends Field[Int]
 case object NOutstandingMemReqsPerChannel extends Field[Int]
 /** Whether to use the slow backup memory port [VLSI] */
 case object UseBackupMemoryPort extends Field[Boolean]
+/** Whether to divide HTIF clock */
+case object UseHtifClockDiv extends Field[Boolean]
 /** Function for building some kind of coherence manager agent */
 case object BuildL2CoherenceManager extends Field[(Int, Parameters) => CoherenceAgent]
 /** Function for building some kind of tile connected to a reset signal */
@@ -120,6 +122,7 @@ class Top(topParams: Parameters) extends Module with HasTopLevelParameters {
   uncore.io.tiles_uncached <> tileList.map(_.io.uncached).flatten
   io.host <> uncore.io.host
   if (p(UseBackupMemoryPort)) { io.mem_backup_ctrl <> uncore.io.mem_backup_ctrl }
+  else { uncore.io.mem_backup_ctrl.en := Bool(false) }
 
   io.mem.zip(uncore.io.mem).foreach { case (outer, inner) =>
     TopUtils.connectNasti(outer, inner)
@@ -189,7 +192,7 @@ class Uncore(implicit val p: Parameters) extends Module
   // Wire the htif to the memory port(s) and host interface
   io.host.debug_stats_csr := htif.io.host.debug_stats_csr
   io.mem <> outmemsys.io.mem
-  if(p(UseBackupMemoryPort)) {
+  if(p(UseHtifClockDiv)) {
     outmemsys.io.mem_backup_en := io.mem_backup_ctrl.en
     VLSIUtils.padOutHTIFWithDividedClock(htif.io.host, scrFile.io.scr,
       outmemsys.io.mem_backup, io.mem_backup_ctrl, io.host, htifW)
@@ -344,5 +347,8 @@ class OuterMemorySystem(implicit val p: Parameters) extends Module with HasTopLe
            "Backup memory port only works when 1 memory channel is enabled")
     require(channelConfigs.sortWith(_ < _)(0) == 1,
                   "Backup memory port requires a single memory port mux config")
-  } else { io.mem <> mem_channels }
+  } else {
+    io.mem <> mem_channels
+    io.mem_backup.req.valid := Bool(false)
+  }
 }