mem: Clean up the xbars a little.

Get rid of comments which just restate the code, get rid of redundant
"virtual" keywords, add "override"s, fix style, and get rid of
xbar::init which was empty and hiding the parent class init.

Change-Id: I8ce20abee340baa88084d142f2fb8c633ee54ba9
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17592
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>

5 files changed, 149 insertions, 203 deletions

diff --git a/src/mem/coherent_xbar.cc b/src/mem/coherent_xbar.cc
index 2bee5bc9d..3e994dd71 100644
--- a/src/mem/coherent_xbar.cc
+++ b/src/mem/coherent_xbar.cc
@@ -71,8 +71,8 @@ CoherentXBar::CoherentXBar(const CoherentXBarParams *p)
         masterPorts.push_back(bp);
         reqLayers.push_back(new ReqLayer(*bp, *this,
                                          csprintf(".reqLayer%d", i)));
-        snoopLayers.push_back(new SnoopRespLayer(*bp, *this,
-                                                 csprintf(".snoopLayer%d", i)));
+        snoopLayers.push_back(
+                new SnoopRespLayer(*bp, *this, csprintf(".snoopLayer%d", i)));
     }
 
     // see if we have a default slave device connected and if so add
@@ -81,10 +81,10 @@ CoherentXBar::CoherentXBar(const CoherentXBarParams *p)
         defaultPortID = masterPorts.size();
         std::string portName = name() + ".default";
         MasterPort* bp = new CoherentXBarMasterPort(portName, *this,
-                                                   defaultPortID);
+                                                    defaultPortID);
         masterPorts.push_back(bp);
         reqLayers.push_back(new ReqLayer(*bp, *this, csprintf(".reqLayer%d",
-                                             defaultPortID)));
+                                         defaultPortID)));
         snoopLayers.push_back(new SnoopRespLayer(*bp, *this,
                                                  csprintf(".snoopLayer%d",
                                                           defaultPortID)));
diff --git a/src/mem/coherent_xbar.hh b/src/mem/coherent_xbar.hh
index 79777b998..2bb5db281 100644
--- a/src/mem/coherent_xbar.hh
+++ b/src/mem/coherent_xbar.hh
@@ -108,35 +108,35 @@ class CoherentXBar : public BaseXBar
 
       protected:
 
-        /**
-         * When receiving a timing request, pass it to the crossbar.
-         */
-        virtual bool recvTimingReq(PacketPtr pkt)
-        { return xbar.recvTimingReq(pkt, id); }
+        bool
+        recvTimingReq(PacketPtr pkt) override
+        {
+            return xbar.recvTimingReq(pkt, id);
+        }
 
-        /**
-         * When receiving a timing snoop response, pass it to the crossbar.
-         */
-        virtual bool recvTimingSnoopResp(PacketPtr pkt)
-        { return xbar.recvTimingSnoopResp(pkt, id); }
+        bool
+        recvTimingSnoopResp(PacketPtr pkt) override
+        {
+            return xbar.recvTimingSnoopResp(pkt, id);
+        }
 
-        /**
-         * When receiving an atomic request, pass it to the crossbar.
-         */
-        virtual Tick recvAtomic(PacketPtr pkt)
-        { return xbar.recvAtomic(pkt, id); }
+        Tick
+        recvAtomic(PacketPtr pkt) override
+        {
+            return xbar.recvAtomic(pkt, id);
+        }
 
-        /**
-         * When receiving a functional request, pass it to the crossbar.
-         */
-        virtual void recvFunctional(PacketPtr pkt)
-        { xbar.recvFunctional(pkt, id); }
+        void
+        recvFunctional(PacketPtr pkt) override
+        {
+            xbar.recvFunctional(pkt, id);
+        }
 
-        /**
-         * Return the union of all adress ranges seen by this crossbar.
-         */
-        virtual AddrRangeList getAddrRanges() const
-        { return xbar.getAddrRanges(); }
+        AddrRangeList
+        getAddrRanges() const override
+        {
+            return xbar.getAddrRanges();
+        }
 
     };
 
@@ -166,42 +166,34 @@ class CoherentXBar : public BaseXBar
          *
          * @return a boolean that is true if this port is snooping
          */
-        virtual bool isSnooping() const
-        { return true; }
+        bool isSnooping() const override { return true; }
 
-        /**
-         * When receiving a timing response, pass it to the crossbar.
-         */
-        virtual bool recvTimingResp(PacketPtr pkt)
-        { return xbar.recvTimingResp(pkt, id); }
-
-        /**
-         * When receiving a timing snoop request, pass it to the crossbar.
-         */
-        virtual void recvTimingSnoopReq(PacketPtr pkt)
-        { return xbar.recvTimingSnoopReq(pkt, id); }
+        bool
+        recvTimingResp(PacketPtr pkt) override
+        {
+            return xbar.recvTimingResp(pkt, id);
+        }
 
-        /**
-         * When receiving an atomic snoop request, pass it to the crossbar.
-         */
-        virtual Tick recvAtomicSnoop(PacketPtr pkt)
-        { return xbar.recvAtomicSnoop(pkt, id); }
+        void
+        recvTimingSnoopReq(PacketPtr pkt) override
+        {
+            return xbar.recvTimingSnoopReq(pkt, id);
+        }
 
-        /**
-         * When receiving a functional snoop request, pass it to the crossbar.
-         */
-        virtual void recvFunctionalSnoop(PacketPtr pkt)
-        { xbar.recvFunctionalSnoop(pkt, id); }
+        Tick
+        recvAtomicSnoop(PacketPtr pkt) override
+        {
+            return xbar.recvAtomicSnoop(pkt, id);
+        }
 
-        /** When reciving a range change from the peer port (at id),
-            pass it to the crossbar. */
-        virtual void recvRangeChange()
-        { xbar.recvRangeChange(id); }
+        void
+        recvFunctionalSnoop(PacketPtr pkt) override
+        {
+            xbar.recvFunctionalSnoop(pkt, id);
+        }
 
-        /** When reciving a retry from the peer port (at id),
-            pass it to the crossbar. */
-        virtual void recvReqRetry()
-        { xbar.recvReqRetry(id); }
+        void recvRangeChange() override { xbar.recvRangeChange(id); }
+        void recvReqRetry() override { xbar.recvReqRetry(id); }
 
     };
 
@@ -231,23 +223,23 @@ class CoherentXBar : public BaseXBar
          * Override the sending of retries and pass them on through
          * the mirrored slave port.
          */
-        void sendRetryResp() {
+        void
+        sendRetryResp() override
+        {
             // forward it as a snoop response retry
             slavePort.sendRetrySnoopResp();
         }
 
-        /**
-         * Provided as necessary.
-         */
-        void recvReqRetry() { panic("SnoopRespPort should never see retry\n"); }
+        void
+        recvReqRetry() override
+        {
+            panic("SnoopRespPort should never see retry");
+        }
 
-        /**
-         * Provided as necessary.
-         */
-        bool recvTimingResp(PacketPtr pkt)
+        bool
+        recvTimingResp(PacketPtr pkt) override
         {
-            panic("SnoopRespPort should never see timing response\n");
-            return false;
+            panic("SnoopRespPort should never see timing response");
         }
 
     };
@@ -280,13 +272,8 @@ class CoherentXBar : public BaseXBar
       * broadcast needed for probes.  NULL denotes an absent filter. */
     SnoopFilter *snoopFilter;
 
-    /** Cycles of snoop response latency.*/
     const Cycles snoopResponseLatency;
-
-    /** Is this crossbar the point of coherency? **/
     const bool pointOfCoherency;
-
-    /** Is this crossbar the point of unification? **/
     const bool pointOfUnification;
 
     /**
@@ -295,24 +282,10 @@ class CoherentXBar : public BaseXBar
      */
     std::unique_ptr<Packet> pendingDelete;
 
-    /** Function called by the port when the crossbar is recieving a Timing
-      request packet.*/
     bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
-
-    /** Function called by the port when the crossbar is recieving a Timing
-      response packet.*/
     bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
-
-    /** Function called by the port when the crossbar is recieving a timing
-        snoop request.*/
     void recvTimingSnoopReq(PacketPtr pkt, PortID master_port_id);
-
-    /** Function called by the port when the crossbar is recieving a timing
-        snoop response.*/
     bool recvTimingSnoopResp(PacketPtr pkt, PortID slave_port_id);
-
-    /** Timing function called by port when it is once again able to process
-     * requests. */
     void recvReqRetry(PortID master_port_id);
 
     /**
@@ -323,7 +296,9 @@ class CoherentXBar : public BaseXBar
      * @param pkt Packet to forward
      * @param exclude_slave_port_id Id of slave port to exclude
      */
-    void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id) {
+    void
+    forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id)
+    {
         forwardTiming(pkt, exclude_slave_port_id, snoopPorts);
     }
 
@@ -339,12 +314,7 @@ class CoherentXBar : public BaseXBar
     void forwardTiming(PacketPtr pkt, PortID exclude_slave_port_id,
                        const std::vector<QueuedSlavePort*>& dests);
 
-    /** Function called by the port when the crossbar is recieving a Atomic
-      transaction.*/
     Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
-
-    /** Function called by the port when the crossbar is recieving an
-        atomic snoop transaction.*/
     Tick recvAtomicSnoop(PacketPtr pkt, PortID master_port_id);
 
     /**
@@ -357,8 +327,8 @@ class CoherentXBar : public BaseXBar
      *
      * @return a pair containing the snoop response and snoop latency
      */
-    std::pair<MemCmd, Tick> forwardAtomic(PacketPtr pkt,
-                                          PortID exclude_slave_port_id)
+    std::pair<MemCmd, Tick>
+    forwardAtomic(PacketPtr pkt, PortID exclude_slave_port_id)
     {
         return forwardAtomic(pkt, exclude_slave_port_id, InvalidPortID,
                              snoopPorts);
@@ -423,7 +393,8 @@ class CoherentXBar : public BaseXBar
      *
      * @return Whether the memory below is the destination for the packet
      */
-    bool isDestination(const PacketPtr pkt) const
+    bool
+    isDestination(const PacketPtr pkt) const
     {
         return (pkt->req->isToPOC() && pointOfCoherency) ||
             (pkt->req->isToPOU() && pointOfUnification);
diff --git a/src/mem/noncoherent_xbar.hh b/src/mem/noncoherent_xbar.hh
index 4ff1ec4fc..9d4efbee2 100644
--- a/src/mem/noncoherent_xbar.hh
+++ b/src/mem/noncoherent_xbar.hh
@@ -104,30 +104,29 @@ class NoncoherentXBar : public BaseXBar
 
       protected:
 
-        /**
-         * When receiving a timing request, pass it to the crossbar.
-         */
-        virtual bool recvTimingReq(PacketPtr pkt)
-        { return xbar.recvTimingReq(pkt, id); }
-
-        /**
-         * When receiving an atomic request, pass it to the crossbar.
-         */
-        virtual Tick recvAtomic(PacketPtr pkt)
-        { return xbar.recvAtomic(pkt, id); }
-
-        /**
-         * When receiving a functional request, pass it to the crossbar.
-         */
-        virtual void recvFunctional(PacketPtr pkt)
-        { xbar.recvFunctional(pkt, id); }
-
-        /**
-         * Return the union of all adress ranges seen by this crossbar.
-         */
-        virtual AddrRangeList getAddrRanges() const
-        { return xbar.getAddrRanges(); }
-
+        bool
+        recvTimingReq(PacketPtr pkt) override
+        {
+            return xbar.recvTimingReq(pkt, id);
+        }
+
+        Tick
+        recvAtomic(PacketPtr pkt) override
+        {
+            return xbar.recvAtomic(pkt, id);
+        }
+
+        void
+        recvFunctional(PacketPtr pkt) override
+        {
+            xbar.recvFunctional(pkt, id);
+        }
+
+        AddrRangeList
+        getAddrRanges() const override
+        {
+            return xbar.getAddrRanges();
+        }
     };
 
     /**
@@ -151,42 +150,29 @@ class NoncoherentXBar : public BaseXBar
 
       protected:
 
-        /**
-         * When receiving a timing response, pass it to the crossbar.
-         */
-        virtual bool recvTimingResp(PacketPtr pkt)
-        { return xbar.recvTimingResp(pkt, id); }
-
-        /** When reciving a range change from the peer port (at id),
-            pass it to the crossbar. */
-        virtual void recvRangeChange()
-        { xbar.recvRangeChange(id); }
-
-        /** When reciving a retry from the peer port (at id),
-            pass it to the crossbar. */
-        virtual void recvReqRetry()
-        { xbar.recvReqRetry(id); }
-
+        bool
+        recvTimingResp(PacketPtr pkt) override
+        {
+            return xbar.recvTimingResp(pkt, id);
+        }
+
+        void
+        recvRangeChange() override
+        {
+            xbar.recvRangeChange(id);
+        }
+
+        void
+        recvReqRetry() override
+        {
+            xbar.recvReqRetry(id);
+        }
     };
 
-    /** Function called by the port when the crossbar is recieving a Timing
-      request packet.*/
     virtual bool recvTimingReq(PacketPtr pkt, PortID slave_port_id);
-
-    /** Function called by the port when the crossbar is recieving a Timing
-      response packet.*/
     virtual bool recvTimingResp(PacketPtr pkt, PortID master_port_id);
-
-    /** Timing function called by port when it is once again able to process
-     * requests. */
     void recvReqRetry(PortID master_port_id);
-
-    /** Function called by the port when the crossbar is recieving a Atomic
-      transaction.*/
     Tick recvAtomic(PacketPtr pkt, PortID slave_port_id);
-
-    /** Function called by the port when the crossbar is recieving a Functional
-        transaction.*/
     void recvFunctional(PacketPtr pkt, PortID slave_port_id);
 
   public:
@@ -195,10 +181,7 @@ class NoncoherentXBar : public BaseXBar
 
     virtual ~NoncoherentXBar();
 
-    /**
-     * stats
-     */
-    virtual void regStats();
+    void regStats() override;
     Stats::Scalar totPktSize;
 };
 
diff --git a/src/mem/xbar.cc b/src/mem/xbar.cc
index 247024eff..9328c2990 100644
--- a/src/mem/xbar.cc
+++ b/src/mem/xbar.cc
@@ -76,11 +76,6 @@ BaseXBar::~BaseXBar()
         delete s;
 }
 
-void
-BaseXBar::init()
-{
-}
-
 Port &
 BaseXBar::getPort(const std::string &if_name, PortID idx)
 {
@@ -136,7 +131,7 @@ BaseXBar::calcPacketTiming(PacketPtr pkt, Tick header_delay)
 }
 
 template <typename SrcType, typename DstType>
-BaseXBar::Layer<SrcType,DstType>::Layer(DstType& _port, BaseXBar& _xbar,
+BaseXBar::Layer<SrcType, DstType>::Layer(DstType& _port, BaseXBar& _xbar,
                                        const std::string& _name) :
     port(_port), xbar(_xbar), _name(_name), state(IDLE),
     waitingForPeer(NULL), releaseEvent([this]{ releaseLayer(); }, name())
@@ -144,7 +139,7 @@ BaseXBar::Layer<SrcType,DstType>::Layer(DstType& _port, BaseXBar& _xbar,
 }
 
 template <typename SrcType, typename DstType>
-void BaseXBar::Layer<SrcType,DstType>::occupyLayer(Tick until)
+void BaseXBar::Layer<SrcType, DstType>::occupyLayer(Tick until)
 {
     // ensure the state is busy at this point, as the layer should
     // transition from idle as soon as it has decided to forward the
@@ -165,7 +160,7 @@ void BaseXBar::Layer<SrcType,DstType>::occupyLayer(Tick until)
 
 template <typename SrcType, typename DstType>
 bool
-BaseXBar::Layer<SrcType,DstType>::tryTiming(SrcType* src_port)
+BaseXBar::Layer<SrcType, DstType>::tryTiming(SrcType* src_port)
 {
     // if we are in the retry state, we will not see anything but the
     // retrying port (or in the case of the snoop ports the snoop
@@ -196,7 +191,7 @@ BaseXBar::Layer<SrcType,DstType>::tryTiming(SrcType* src_port)
 
 template <typename SrcType, typename DstType>
 void
-BaseXBar::Layer<SrcType,DstType>::succeededTiming(Tick busy_time)
+BaseXBar::Layer<SrcType, DstType>::succeededTiming(Tick busy_time)
 {
     // we should have gone from idle or retry to busy in the tryTiming
     // test
@@ -208,7 +203,7 @@ BaseXBar::Layer<SrcType,DstType>::succeededTiming(Tick busy_time)
 
 template <typename SrcType, typename DstType>
 void
-BaseXBar::Layer<SrcType,DstType>::failedTiming(SrcType* src_port,
+BaseXBar::Layer<SrcType, DstType>::failedTiming(SrcType* src_port,
                                               Tick busy_time)
 {
     // ensure no one got in between and tried to send something to
@@ -230,7 +225,7 @@ BaseXBar::Layer<SrcType,DstType>::failedTiming(SrcType* src_port,
 
 template <typename SrcType, typename DstType>
 void
-BaseXBar::Layer<SrcType,DstType>::releaseLayer()
+BaseXBar::Layer<SrcType, DstType>::releaseLayer()
 {
     // releasing the bus means we should now be idle
     assert(state == BUSY);
@@ -254,7 +249,7 @@ BaseXBar::Layer<SrcType,DstType>::releaseLayer()
 
 template <typename SrcType, typename DstType>
 void
-BaseXBar::Layer<SrcType,DstType>::retryWaiting()
+BaseXBar::Layer<SrcType, DstType>::retryWaiting()
 {
     // this should never be called with no one waiting
     assert(!waitingForLayer.empty());
@@ -289,7 +284,7 @@ BaseXBar::Layer<SrcType,DstType>::retryWaiting()
 
 template <typename SrcType, typename DstType>
 void
-BaseXBar::Layer<SrcType,DstType>::recvRetry()
+BaseXBar::Layer<SrcType, DstType>::recvRetry()
 {
     // we should never get a retry without having failed to forward
     // something to this port
@@ -573,7 +568,7 @@ BaseXBar::regStats()
 
 template <typename SrcType, typename DstType>
 DrainState
-BaseXBar::Layer<SrcType,DstType>::drain()
+BaseXBar::Layer<SrcType, DstType>::drain()
 {
     //We should check that we're not "doing" anything, and that noone is
     //waiting. We might be idle but have someone waiting if the device we
@@ -588,7 +583,7 @@ BaseXBar::Layer<SrcType,DstType>::drain()
 
 template <typename SrcType, typename DstType>
 void
-BaseXBar::Layer<SrcType,DstType>::regStats()
+BaseXBar::Layer<SrcType, DstType>::regStats()
 {
     using namespace Stats;
 
@@ -611,5 +606,5 @@ BaseXBar::Layer<SrcType,DstType>::regStats()
  * file, but since there are only two given options (MasterPort and
  * SlavePort) it seems a bit excessive at this point.
  */
-template class BaseXBar::Layer<SlavePort,MasterPort>;
-template class BaseXBar::Layer<MasterPort,SlavePort>;
+template class BaseXBar::Layer<SlavePort, MasterPort>;
+template class BaseXBar::Layer<MasterPort, SlavePort>;
diff --git a/src/mem/xbar.hh b/src/mem/xbar.hh
index 674515001..fbd17e50b 100644
--- a/src/mem/xbar.hh
+++ b/src/mem/xbar.hh
@@ -116,9 +116,6 @@ class BaseXBar : public MemObject
          */
         DrainState drain() override;
 
-        /**
-         * Get the crossbar layer's name
-         */
         const std::string name() const { return xbar.name() + _name; }
 
 
@@ -154,7 +151,6 @@ class BaseXBar : public MemObject
          */
         void failedTiming(SrcType* src_port, Tick busy_time);
 
-        /** Occupy the layer until until */
         void occupyLayer(Tick until);
 
         /**
@@ -170,9 +166,6 @@ class BaseXBar : public MemObject
          */
         void recvRetry();
 
-        /**
-         * Register stats for the layer
-         */
         void regStats();
 
       protected:
@@ -193,7 +186,6 @@ class BaseXBar : public MemObject
         /** The crossbar this layer is a part of. */
         BaseXBar& xbar;
 
-        /** A name for this layer. */
         std::string _name;
 
         /**
@@ -214,7 +206,6 @@ class BaseXBar : public MemObject
          */
         enum State { IDLE, BUSY, RETRY };
 
-        /** track the state of the layer */
         State state;
 
         /**
@@ -235,8 +226,6 @@ class BaseXBar : public MemObject
          * potential waiting port, or drain if asked to do so.
          */
         void releaseLayer();
-
-        /** event used to schedule a release of the layer */
         EventFunctionWrapper releaseEvent;
 
         /**
@@ -249,7 +238,7 @@ class BaseXBar : public MemObject
 
     };
 
-    class ReqLayer : public Layer<SlavePort,MasterPort>
+    class ReqLayer : public Layer<SlavePort, MasterPort>
     {
       public:
         /**
@@ -260,15 +249,18 @@ class BaseXBar : public MemObject
          * @param _name the layer's name
          */
         ReqLayer(MasterPort& _port, BaseXBar& _xbar, const std::string& _name) :
-            Layer(_port, _xbar, _name) {}
+            Layer(_port, _xbar, _name)
+        {}
 
       protected:
-
-        void sendRetry(SlavePort* retry_port)
-        { retry_port->sendRetryReq(); }
+        void
+        sendRetry(SlavePort* retry_port) override
+        {
+            retry_port->sendRetryReq();
+        }
     };
 
-    class RespLayer : public Layer<MasterPort,SlavePort>
+    class RespLayer : public Layer<MasterPort, SlavePort>
     {
       public:
         /**
@@ -278,16 +270,20 @@ class BaseXBar : public MemObject
          * @param _xbar the crossbar this layer belongs to
          * @param _name the layer's name
          */
-        RespLayer(SlavePort& _port, BaseXBar& _xbar, const std::string& _name) :
-            Layer(_port, _xbar, _name) {}
+        RespLayer(SlavePort& _port, BaseXBar& _xbar,
+                  const std::string& _name) :
+            Layer(_port, _xbar, _name)
+        {}
 
       protected:
-
-        void sendRetry(MasterPort* retry_port)
-        { retry_port->sendRetryResp(); }
+        void
+        sendRetry(MasterPort* retry_port) override
+        {
+            retry_port->sendRetryResp();
+        }
     };
 
-    class SnoopRespLayer : public Layer<SlavePort,MasterPort>
+    class SnoopRespLayer : public Layer<SlavePort, MasterPort>
     {
       public:
         /**
@@ -299,12 +295,16 @@ class BaseXBar : public MemObject
          */
         SnoopRespLayer(MasterPort& _port, BaseXBar& _xbar,
                        const std::string& _name) :
-            Layer(_port, _xbar, _name) {}
+            Layer(_port, _xbar, _name)
+        {}
 
       protected:
 
-        void sendRetry(SlavePort* retry_port)
-        { retry_port->sendRetrySnoopResp(); }
+        void
+        sendRetry(SlavePort* retry_port) override
+        {
+            retry_port->sendRetrySnoopResp();
+        }
     };
 
     /**
@@ -312,9 +312,7 @@ class BaseXBar : public MemObject
      * and to decode the address.
      */
     const Cycles frontendLatency;
-    /** Cycles of forward latency */
     const Cycles forwardLatency;
-    /** Cycles of response latency */
     const Cycles responseLatency;
     /** the width of the xbar in bytes */
     const uint32_t width;
@@ -417,7 +415,6 @@ class BaseXBar : public MemObject
                   PortID idx=InvalidPortID) override;
 
     void regStats() override;
-
 };
 
 #endif //__MEM_XBAR_HH__