Changeset 463 for branches

Timestamp:

Jul 19, 2013, 4:52:06 PM (11 years ago)

Author:

cfuguet

Message:

Modification in vci_cc_vcache_wrapper:

• Optimization in DCACHE/ICACHE CC_CHECK state. If pending request to CC_SEND, we wait in the CC_CHECK state. Doing this, during the wait, we can handle incoming CLACK avoiding any deadlock situation.

The states CC_UPDT and CC_INVAL do not need to test anymore if
there is a pending request to CC_SEND.

File:

• branches/v5/modules/vci_cc_vcache_wrapper/caba/source/src/vci_cc_vcache_wrapper.cpp (modified) (6 diffs)

branches/v5/modules/vci_cc_vcache_wrapper/caba/source/src/vci_cc_vcache_wrapper.cpp

@@ -1900 +1900 @@
         }
 
+        // wait if pending request to CC_SEND. This way if there are pending
+        // CLACK they can be treated in this state and then a deadlock
+        // situation is avoided
+        if ( r_icache_cc_send_req.read() ) break;
+
         // CC request handler
 
@@ -1955 +1960 @@
     case ICACHE_CC_INVAL:       // hit inval : switch slot to ZOMBI state
     {
-        // return to CC_CHECK if pending request to CC_SEND
-        // to handle possible pending CLACK and avoid deadlock
-        if (r_icache_cc_send_req.read())
-        {
-            r_icache_fsm = ICACHE_CC_CHECK;
-            break; 
-        } 
+        assert (not r_icache_cc_send_req.read() &&
+                "ERROR in ICACHE_CC_INVAL: the r_icache_cc_send_req "
+                "must not be set");
 
 #ifdef INSTRUMENTATION
@@ -1996 +1997 @@
     case ICACHE_CC_UPDT:        // hit update : write one word per cycle
     {
-
-        // if pending request to CC_SEND or if the CC_UPDT data is not ready to
-        // handle possible pending CLACK and avoid deadlock
-        if ( r_icache_cc_send_req.read() )
-        {
-            r_icache_fsm = ICACHE_CC_CHECK;
-            break;
-        }
+        assert (not r_icache_cc_send_req.read() &&
+                "ERROR in ICACHE_CC_UPDT: the r_icache_cc_send_req "
+                "must not be set");
 
         if ( not r_cc_receive_updt_fifo_be.rok() ) break;
@@ -4657 +4653 @@
         }
 
+        // wait if pending request to CC_SEND. This way if there are pending
+        // CLACK they can be treated in this state and then a deadlock
+        // situation is avoided
+        if ( r_dcache_cc_send_req.read() ) break;
+
         // CC request handler
        
@@ -4754 +4755 @@
         }
 
-        // return to CC_CHECK if pending request to CC_SEND
-        // to handle possible pending CLACK and avoid deadlock
-        if ( r_dcache_cc_send_req.read() )
-        {
-            r_dcache_fsm = DCACHE_CC_CHECK;
-            break;
-        }
+        assert (not r_dcache_cc_send_req.read() &&
+                "ERROR in DCACHE_CC_INVAL: the r_dcache_cc_send_req "
+                "must not be set");
 
         // Switch slot state to ZOMBI and send CLEANUP command 
@@ -4821 +4818 @@
         }
 
-        // if pending request to CC_SEND or if the CC_UPDT data is not ready to
-        // handle possible pending CLACK and avoid deadlock
-        if ( r_dcache_cc_send_req.read() )
-        {
-            r_dcache_fsm = DCACHE_CC_CHECK;
-            break;
-        }
+        assert (not r_dcache_cc_send_req.read() &&
+                "ERROR in DCACHE_CC_INVAL: the r_dcache_cc_send_req "
+                "must not be set");
         
         if ( not r_cc_receive_updt_fifo_be.rok() ) break;