OvmfPkg: VirtioNetDxe: add SNP.Initialize and shared dependencies

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14410 6f19259b-4bc3-4df7-8a09-765794883524

OvmfPkg/VirtioNetDxe/SnpSharedHelpers.c

@@ -0,0 +1,53 @@
+/** @file
+
+  Helper functions used by at least two Simple Network Protocol methods.
+
+  Copyright (C) 2013, Red Hat, Inc.
+
+  This program and the accompanying materials are licensed and made available
+  under the terms and conditions of the BSD License which accompanies this
+  distribution. The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
+  WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Library/MemoryAllocationLib.h>
+
+#include "VirtioNet.h"
+
+/**
+  Release RX and TX resources on the boundary of the
+  EfiSimpleNetworkInitialized state.
+
+  These functions contribute to rolling back a partial, failed initialization
+  of the virtio-net SNP driver instance, or to shutting down a fully
+  initialized, running instance.
+
+  They are only callable by the VirtioNetInitialize() and the
+  VirtioNetShutdown() SNP methods. See the state diagram in "VirtioNet.h".
+
+  @param[in,out] Dev  The VNET_DEV driver instance being shut down, or whose
+                      partial, failed initialization is being rolled back.
+*/
+
+VOID
+EFIAPI
+VirtioNetShutdownRx (
+  IN OUT VNET_DEV *Dev
+  )
+{
+  FreePool (Dev->RxBuf);
+}
+
+
+VOID
+EFIAPI
+VirtioNetShutdownTx (
+  IN OUT VNET_DEV *Dev
+  )
+{
+  FreePool (Dev->TxFreeStack);
+}