ruby: single physical memory in fs mode

Both ruby and the system used to maintain memory copies.  With the changes
carried for programmed io accesses, only one single memory is required for
fs simulations.  This patch sets the copy of memory that used to reside
with the system to null, so that no space is allocated, but address checks
can still be carried out.  All the memory accesses now source and sink values
to the memory maintained by ruby.

3 files changed, 10 insertions, 23 deletions

diff --git a/src/mem/ruby/system/DMASequencer.cc b/src/mem/ruby/system/DMASequencer.cc
index 66b6e404a..eb4ce6123 100644
--- a/src/mem/ruby/system/DMASequencer.cc
+++ b/src/mem/ruby/system/DMASequencer.cc
@@ -40,9 +40,8 @@
 DMASequencer::DMASequencer(const Params *p)
     : MemObject(p), m_version(p->version), m_controller(NULL),
       m_mandatory_q_ptr(NULL), m_usingRubyTester(p->using_ruby_tester),
-      slave_port(csprintf("%s.slave", name()), this, access_phys_mem, 0),
-      drainManager(NULL), system(p->system), retry(false),
-      access_phys_mem(p->access_phys_mem)
+      slave_port(csprintf("%s.slave", name()), this, 0),
+      drainManager(NULL), system(p->system), retry(false)
 {
     assert(m_version != -1);
 }
@@ -56,6 +55,8 @@ DMASequencer::init()
     m_mandatory_q_ptr->setSender(this);
     m_is_busy = false;
     m_data_block_mask = ~ (~0 << RubySystem::getBlockSizeBits());
+
+    slave_port.sendRangeChange();
 }
 
 BaseSlavePort &
@@ -72,9 +73,8 @@ DMASequencer::getSlavePort(const std::string &if_name, PortID idx)
 }
 
 DMASequencer::MemSlavePort::MemSlavePort(const std::string &_name,
-    DMASequencer *_port, bool _access_phys_mem, PortID id)
-    : QueuedSlavePort(_name, _port, queue, id), queue(*_port, *this),
-      access_phys_mem(_access_phys_mem)
+    DMASequencer *_port, PortID id)
+    : QueuedSlavePort(_name, _port, queue, id), queue(*_port, *this)
 {
     DPRINTF(RubyDma, "Created slave memport on ruby sequencer %s\n", _name);
 }
@@ -202,28 +202,21 @@ void
 DMASequencer::MemSlavePort::hitCallback(PacketPtr pkt)
 {
     bool needsResponse = pkt->needsResponse();
-    bool accessPhysMem = access_phys_mem;
-
     assert(!pkt->isLLSC());
     assert(!pkt->isFlush());
 
     DPRINTF(RubyDma, "Hit callback needs response %d\n", needsResponse);
 
-    if (accessPhysMem) {
-        DMASequencer *seq = static_cast<DMASequencer *>(&owner);
-        seq->system->getPhysMem().access(pkt);
-    } else if (needsResponse) {
-        pkt->makeResponse();
-    }
-
     // turn packet around to go back to requester if response expected
     if (needsResponse) {
+        pkt->makeResponse();
         DPRINTF(RubyDma, "Sending packet back over port\n");
         // send next cycle
         schedTimingResp(pkt, curTick() + g_system_ptr->clockPeriod());
     } else {
         delete pkt;
     }
+
     DPRINTF(RubyDma, "Hit callback done!\n");
 }
 
diff --git a/src/mem/ruby/system/DMASequencer.hh b/src/mem/ruby/system/DMASequencer.hh
index a24db2d34..be386f1a1 100644
--- a/src/mem/ruby/system/DMASequencer.hh
+++ b/src/mem/ruby/system/DMASequencer.hh
@@ -66,11 +66,10 @@ class DMASequencer : public MemObject
     {
       private:
         SlavePacketQueue queue;
-        bool access_phys_mem;
 
       public:
         MemSlavePort(const std::string &_name, DMASequencer *_port,
-               bool _access_phys_mem, PortID id);
+                     PortID id);
         void hitCallback(PacketPtr pkt);
         void evictionCallback(const Address& address);
 
@@ -140,8 +139,6 @@ class DMASequencer : public MemObject
     System* system;
 
     bool retry;
-    bool access_phys_mem;
-
     bool m_is_busy;
     uint64_t m_data_block_mask;
     DMARequest active_request;
diff --git a/src/mem/ruby/system/Sequencer.py b/src/mem/ruby/system/Sequencer.py
index 8bad83db5..6f64207dc 100644
--- a/src/mem/ruby/system/Sequencer.py
+++ b/src/mem/ruby/system/Sequencer.py
@@ -73,12 +73,9 @@ class RubySequencer(RubyPort):
 class DMASequencer(MemObject):
     type = 'DMASequencer'
     cxx_header = "mem/ruby/system/DMASequencer.hh"
-    version = Param.Int(0, "")
 
+    version = Param.Int(0, "")
     slave = SlavePort("Device slave port")
-
     using_ruby_tester = Param.Bool(False, "")
-    access_phys_mem = Param.Bool(True,
-            "should the dma atomically update phys_mem")
     ruby_system = Param.RubySystem(Parent.any, "")
     system = Param.System(Parent.any, "system object")