dev-amdgpu: Add memory manager for GPU VRAM

The memory manager is responsible for reading and writes to VRAM memory
for direct requests that bypass GPU caches.

Change-Id: I4aa1e77737ce52f2f2c01929b58984126bdcb925
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/51850
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/dev/amdgpu/amdgpu_device.cc

@@ -250,6 +250,8 @@ AMDGPUDevice::write(PacketPtr pkt)
 
     switch (barnum) {
       case FRAMEBUFFER_BAR:
+          gpuMemMgr->writeRequest(offset, pkt->getPtr<uint8_t>(),
+                                  pkt->getSize());
           writeFrame(pkt, offset);
           break;
       case DOORBELL_BAR:
@@ -266,6 +268,9 @@ AMDGPUDevice::write(PacketPtr pkt)
     // Reads return 0 by default.
     uint64_t data = pkt->getUintX(ByteOrder::little);
 
+    DPRINTF(AMDGPUDevice, "PCI Write to %#lx data %#lx\n",
+                            pkt->getAddr(), data);
+
     if (data || regs.find(pkt->getAddr()) != regs.end())
         regs[pkt->getAddr()] = data;