mem: Add DRAM device size and check against config

This patch adds the size of the DRAM device to the DRAM config. It
also compares the actual DRAM size (calculated using information from
the config) to the size defined in the system. If these two values do
not match gem5 will print a warning. In order to do correct DRAM
research the size of the memory defined in the system should match the
size of the DRAM in the config. The timing and current parameters
found in the DRAM configs are defined for a DRAM device with a
specific size and would differ for another device with a different
size.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/mem/dram_ctrl.cc b/src/mem/dram_ctrl.cc
index ac78a3d1e..c9d944faa 100644
--- a/src/mem/dram_ctrl.cc
+++ b/src/mem/dram_ctrl.cc
@@ -62,6 +62,7 @@ DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) :
     nextReqEvent(this), respondEvent(this), activateEvent(this),
     prechargeEvent(this), refreshEvent(this), powerEvent(this),
     drainManager(NULL),
+    deviceSize(p->device_size),
     deviceBusWidth(p->device_bus_width), burstLength(p->burst_length),
     deviceRowBufferSize(p->device_rowbuffer_size),
     devicesPerRank(p->devices_per_rank),
@@ -139,6 +140,16 @@ DRAMCtrl::DRAMCtrl(const DRAMCtrlParams* p) :
     // determine the rows per bank by looking at the total capacity
     uint64_t capacity = ULL(1) << ceilLog2(AbstractMemory::size());
 
+    // determine the dram actual capacity from the DRAM config in Mbytes
+    uint64_t deviceCapacity = deviceSize / (1024 * 1024) * devicesPerRank *
+        ranksPerChannel;
+
+    // if actual DRAM size does not match memory capacity in system warn!
+    if (deviceCapacity != capacity / (1024 * 1024))
+        warn("DRAM device capacity (%d Mbytes) does not match the "
+             "address range assigned (%d Mbytes)\n", deviceCapacity,
+             capacity / (1024 * 1024));
+
     DPRINTF(DRAM, "Memory capacity %lld (%lld) bytes\n", capacity,
             AbstractMemory::size());