internal IntelRingBuffer(uint capacity)
//requires capacity > 0 && IsPowerOf2(capacity);
{
uint length = capacity * DescriptorBytes;
DmaMemory region = new DmaMemory((int)length); //TODO: DmaMemory.AllocatePhysical(length, AlignmentBytes);
// (ARM only, not x86) PlatformService.SetCacheAttributes(region.VirtualAddress,
// (UIntPtr)region.Length,
// false,
// false);
this.region = region;
this.mapEntries = new MapEntry [capacity];
for (int i = 0; i < capacity; i++) {
this.mapEntries[i].mem = new DmaMemory((int)Intel.IEEE8023FrameBytes);
}
this.capacity = capacity;
this.head = 0;
this.tail = 0;
this.count = 0;
// Clear out ring buffer
for (int i = 0; i < region.Length; i += 4) {
region.Write32(i, 0);
}
}
private Packet MakePacketFromDescriptor(DmaMemory mem, ulong controlBits)
{
PacketFifo inDevPkts = rxPacketsInDevice.Acquire();
Packet packet = inDevPkts.Pop();
int length = (int)((controlBits & RxDescriptor.LENGTH_MASK)
>> RxDescriptor.LENGTH_SHIFT);
uint stat_err = (uint)((controlBits & RxDescriptor.ERR_STAT_MASK)
>> RxDescriptor.ERR_STAT_SHIFT);
// can't deal with fragments yet
if ((stat_err & RxErrStatFields.END_OF_PACKET) == 0)
{
INucleusCalls.DebugPrintHex(40, 0xd0);
DebugStub.Print("FRAGMENT\n");
throw new Exception();
}
//DebugStub.Assert((stat_err & RxErrStatFields.END_OF_PACKET) != 0);
//DebugStub.Assert(packet.GetFragmentVirtualAddress(0) == fragmentVirtAddr);
packet.FromDeviceFlags = GetRecvPktFlags(stat_err);
packet.SetFragment(0, mem.BytesRef(0, length));
rxPacketsInDevice.Release(inDevPkts);
return(packet);
}
// Returns true if hardware is done with this descriptor.
internal bool Peek(out DmaMemory mem,
out ulong controlBits)
{
if (this.count > 0) {
UIntPtr pa;
ReadDescriptor(this.tail, out pa, out controlBits);
DebugStub.Assert(pa == this.mapEntries[tail].PhysicalAddress);
mem = this.mapEntries[tail].mem;
return ((controlBits & Descriptor.DESCRIPTOR_DONE) != 0);
} else {
mem = null;
controlBits = 0;
return false;
}
}
///////////////////////////////////////////////////////////////////////
//
// Buffer Operations, should only be called when a lock is held
// this ring buffer.
//
private void _LockedPushTsmtBuffer(Packet packet)
{
// (ARM only, not x86) PlatformService.CleanAndInvalidateDCache(packetVirtAddr, (UIntPtr)length);
int length = packet.GetLength();
ulong controlBits = (ulong)ByteOrder.HostToLittleEndian(length);
// set necessary command fields
controlBits |= (TxCmdFields.END_OF_PACKET | TxCmdFields.INSERT_FCS |
TxCmdFields.REPORT_STATUS);
DmaMemory mem = txRingBuffer.PeekHead();
packet.CopyToBytes(mem.BytesRef());
txRingBuffer.Push(controlBits);
}
