Changeset 1011 for branches/reconfiguration/modules/vci_mem_cache/caba/source/include/vci_mem_cache.h

Timestamp:

Aug 15, 2015, 9:02:55 PM (9 years ago)

Author:

cfuguet

Message:

reconf: introduce a scratchpad mode in the memory cache.

• Initialize the memory cache directory with all slots valid. The cache lines correspond to the lowest local memory segment (i.e. the first 256 Kbytes).

• If there is a read or write miss while in scratchpad mode, the request is dropped (black-hole behavior).

• In scratchpad mode, when a broadcast invalidate is triggered by a write, the line is not invalidated. The Read FSM needs to check in the IVT if there is a pending invalidate during a read. The same for the Cleanup FSM. This additional IVT check is only performed when in scratchpad mode.

• TODO: Support of the scratchpad mode on the CAS FSM. But probably not needed because the distributed bootloader initializes the Local, Remote and Dirty flags to 1 before enabling the MMU.

File:

• branches/reconfiguration/modules/vci_mem_cache/caba/source/include/vci_mem_cache.h (modified) (6 diffs)

branches/reconfiguration/modules/vci_mem_cache/caba/source/include/vci_mem_cache.h

@@ -202 +202 @@
         READ_TRT_LOCK,
         READ_TRT_SET,
-        READ_TRT_REQ
+        READ_TRT_REQ,
+        READ_IVT_LOCK
       };
 
@@ -367 +368 @@
         ALLOC_IVT_CLEANUP,
         ALLOC_IVT_CAS,
-        ALLOC_IVT_CONFIG
+        ALLOC_IVT_CONFIG,
+        ALLOC_IVT_READ
       };
 
@@ -540 +542 @@
       private:
 
+      void scratchpad_reset();
       void transition();
       void genMoore();
@@ -644 +647 @@
       //////////////////////////////////////////////////
 
-      sc_signal<int>         r_tgt_cmd_fsm;
+      sc_signal<int>      r_tgt_cmd_fsm;
 
       ///////////////////////////////////////////////////////
@@ -668 +671 @@
       sc_signal<size_t>   r_config_trt_index;         // selected entry in TRT
       sc_signal<size_t>   r_config_ivt_index;         // selected entry in IVT
+      sc_signal<bool>     r_config_scratchpad;        // enable scratchpad mode
 
       // Buffer between CONFIG fsm and IXR_CMD fsm
@@ -820 +824 @@
       sc_signal<size_t>   r_cleanup_next_ptr;      // next pointer to the heap
       sc_signal<tag_t>    r_cleanup_tag;           // cache line tag (in directory)
+      sc_signal<bool>     r_cleanup_valid;         // valid bit (in directory)
       sc_signal<bool>     r_cleanup_is_cnt;        // inst bit (in directory)
       sc_signal<bool>     r_cleanup_lock;          // lock bit (in directory)