mem: Add DRAM cycle time

This patch extends the current timing parameters with the DRAM cycle
time. This is needed as the DRAMPower tool expects timestamps in DRAM
cycles. At the moment we could get away with doing this in a
post-processing step as the DRAMPower execution is separate from the
simulation run. However, in the long run we want the tool to be called
during the simulation, and then the cycle time is needed.

src/mem/DRAMCtrl.py

@@ -119,6 +119,9 @@ class DRAMCtrl(AbstractMemory):
 
     # timing behaviour and constraints - all in nanoseconds
 
+    # the base clock period of the DRAM
+    tCK = Param.Latency("Clock period")
+
     # the amount of time in nanoseconds from issuing an activate command
     # to the data being available in the row buffer for a read/write
     tRCD = Param.Latency("RAS to CAS delay")
@@ -195,6 +198,9 @@ class DDR3_1600_x64(DRAMCtrl):
     # DDR3 has 8 banks in all configurations
     banks_per_rank = 8
 
+    # 800 MHz
+    tCK = '1.25ns'
+
     # DDR3-1600 11-11-11-28
     tRCD = '13.75ns'
     tCL = '13.75ns'
@@ -256,6 +262,9 @@ class DDR3_1333_x64_DRAMSim2(DRAMCtrl):
     # DDR3 has 8 banks in all configurations
     banks_per_rank = 8
 
+    # 666 MHs
+    tCK = '1.5ns'
+
     tRCD = '15ns'
     tCL = '15ns'
     tRP = '15ns'
@@ -307,6 +316,9 @@ class LPDDR2_S4_1066_x32(DRAMCtrl):
     # LPDDR2-S4 has 8 banks in all configurations
     banks_per_rank = 8
 
+    # 533 MHz
+    tCK = '1.876ns'
+
     # Fixed at 15 ns
     tRCD = '15ns'
 
@@ -367,6 +379,9 @@ class WideIO_200_x128(DRAMCtrl):
     # WideIO has 4 banks in all configurations
     banks_per_rank = 4
 
+    # 200 MHz
+    tCK = '5ns'
+
     # WIO-200
     tRCD = '18ns'
     tCL = '18ns'
@@ -421,6 +436,9 @@ class LPDDR3_1600_x32(DRAMCtrl):
     # LPDDR3 has 8 banks in all configurations
     banks_per_rank = 8
 
+    # 800 MHz
+    tCK = '1.25ns'
+
     # Fixed at 15 ns
     tRCD = '15ns'
 

src/mem/dram_ctrl.cc

@@ -74,7 +74,7 @@ DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) :
     writeLowThreshold(writeBufferSize * p->write_low_thresh_perc / 100.0),
     minWritesPerSwitch(p->min_writes_per_switch),
     writesThisTime(0), readsThisTime(0),
-    tWTR(p->tWTR), tRTW(p->tRTW), tBURST(p->tBURST),
+    tCK(p->tCK), tWTR(p->tWTR), tRTW(p->tRTW), tBURST(p->tBURST),
     tRCD(p->tRCD), tCL(p->tCL), tRP(p->tRP), tRAS(p->tRAS), tWR(p->tWR),
     tRTP(p->tRTP), tRFC(p->tRFC), tREFI(p->tREFI), tRRD(p->tRRD),
     tXAW(p->tXAW), activationLimit(p->activation_limit),

src/mem/dram_ctrl.hh

@@ -468,6 +468,7 @@ class DRAMCtrl : public AbstractMemory
      * Basic memory timing parameters initialized based on parameter
      * values.
      */
+    const Tick tCK;
     const Tick tWTR;
     const Tick tRTW;
     const Tick tBURST;