Changeset 912 for trunk/modules/vci_mem_cache

Timestamp:

Jan 2, 2015, 1:18:51 PM (10 years ago)

Author:

alain

Message:

The hard lock implemented as an addressable register in the configuration interface
of the vci_mem_cache has been removed, as it created a possible live-lock situation.
It should be replaced by an external software queuing lock in case of concurrent access.
This lock was only used by the INVAL and SYNC request for software L2/L3 cache coherence.
The tsar_boot preloader and the giet-vm mmc_driver have been accordingly updated.

Location:

trunk/modules/vci_mem_cache

Files:

• caba/source/src/vci_mem_cache.cpp (modified) (6 diffs)
• include/soclib/mem_cache.h (modified) (1 diff)

trunk/modules/vci_mem_cache/caba/source/src/vci_mem_cache.cpp

@@ -469 +469 @@
         r_alloc_heap_fsm("r_alloc_heap_fsm"),
         r_alloc_heap_reset_cpt("r_alloc_heap_reset_cpt")
+
 #if MONITOR_MEMCACHE_FSM == 1
         ,
@@ -879 +880 @@
     }
 
-    /////////////////////////////////////////
+    //////////////////////////////////////////////////////////////
     tmpl(void)::print_stats(bool activity_counters, bool stats)
-    /////////////////////////////////////////
+    /////////////////////////////////////////////////////////////
     {
         std::cout << "**********************************" << std::dec << std::endl;
@@ -1058 +1059 @@
 
             r_config_cmd  = MEMC_CMD_NOP;
-            r_config_lock = false;
 
             m_config_to_cc_send_inst_fifo.init();
@@ -1448 +1448 @@
                     case MEMC_CONFIG:
                     {
-                        if ((p_vci_tgt.cmd.read() == vci_param_int::CMD_READ) // get lock
-                                and (regr == MEMC_LOCK))
-                        {
-                            rdata         = (uint32_t) r_config_lock.read();
-                            need_rsp      = true;
-                            error         = 0;
-                            r_config_lock = true;
-                        }
-                        else if ((p_vci_tgt.cmd.read() == vci_param_int::CMD_WRITE)  // release lock
-                                and (regr == MEMC_LOCK))
-                        {
-                            need_rsp = true;
-                            error    = 0;
-                            r_config_lock = false;
-                        }
-                        else if ((p_vci_tgt.cmd.read() == vci_param_int::CMD_WRITE)   // set addr_lo
+                        if ((p_vci_tgt.cmd.read() == vci_param_int::CMD_WRITE)   // set addr_lo
                                 and (regr == MEMC_ADDR_LO))
                         {
@@ -1992 +1977 @@
         //    CONFIG FSM
         ////////////////////////////////////////////////////////////////////////////////////
-        // The CONFIG FSM handles the VCI configuration requests (INVAL & SYNC).
+        // The CONFIG FSM handles the L2/L3 coherence requests:
         // The target buffer can have any size, and there is one single command for
         // all cache lines covered by the target buffer.
-        //
-        // An INVAL or SYNC configuration operation is defined by the following registers:
+        // An INVAL or SYNC operation is defined by the following registers:
         // - bool      r_config_cmd        : INVAL / SYNC / NOP
         // - uint64_t  r_config_address    : buffer base address
@@ -2036 +2020 @@
         //   The CONFIG SYNC response is sent only when the last PUT response is received.
         //
-        // From the software point of view, a configuration request is a sequence
-        // of 6 atomic accesses in an uncached segment. A dedicated lock is used
-        // to handle only one configuration command at a given time:
-        // - Read  MEMC_LOCK       : Get the lock
+        // From the software point of view, a L2/L3 coherence request is a sequence
+        // of 4 atomic accesses in an uncached segment:
         // - Write MEMC_ADDR_LO    : Set the buffer address LSB
         // - Write MEMC_ADDR_HI    : Set the buffer address MSB
         // - Write MEMC_BUF_LENGTH : set buffer length (bytes)
         // - Write MEMC_CMD_TYPE   : launch the actual operation
-        // - WRITE MEMC_LOCK       : release the lock
         ////////////////////////////////////////////////////////////////////////////////////
 

trunk/modules/vci_mem_cache/include/soclib/mem_cache.h

@@ -39 +39 @@
 enum SoclibMemCacheConfigRegs
 {
-    MEMC_LOCK,
     MEMC_ADDR_LO,
     MEMC_ADDR_HI,