mem: Added support for Null data packet

The packet now identifies whether static or dynamic data has been allocated and
is used by Ruby to determine whehter to copy the data pointer into the ruby
request.  Subsequently, Ruby can be told not to update phys memory when
receiving packets.

1 files changed, 8 insertions, 4 deletions

diff --git a/src/mem/ruby/system/DMASequencer.cc b/src/mem/ruby/system/DMASequencer.cc
index 63e1f76e6..b36f8780b 100644
--- a/src/mem/ruby/system/DMASequencer.cc
+++ b/src/mem/ruby/system/DMASequencer.cc
@@ -97,8 +97,10 @@ DMASequencer::makeRequest(const RubyRequest &request)
     msg->getLen() = (offset + len) <= RubySystem::getBlockSizeBytes() ?
         len : RubySystem::getBlockSizeBytes() - offset;
 
-    if (write) {
-        msg->getDataBlk().setData(data, offset, msg->getLen());
+    if (write && (data != NULL)) {
+        if (active_request.data != NULL) {
+            msg->getDataBlk().setData(data, offset, msg->getLen());
+        }
     }
 
     assert(m_mandatory_q_ptr != NULL);
@@ -160,8 +162,10 @@ DMASequencer::dataCallback(const DataBlock & dblk)
     if (active_request.bytes_completed == 0)
         offset = active_request.start_paddr & m_data_block_mask;
     assert(active_request.write == false);
-    memcpy(&active_request.data[active_request.bytes_completed],
-           dblk.getData(offset, len), len);
+    if (active_request.data != NULL) {
+        memcpy(&active_request.data[active_request.bytes_completed],
+               dblk.getData(offset, len), len);
+    }
     issueNext();
 }