[idd] lgmp: stream staged copies to WC memory

idd/LGCommon/WCWrite.h

@@ -0,0 +1,32 @@
+/**
+ * Looking Glass
+ * Copyright © 2017-2026 The Looking Glass Authors
+ * https://looking-glass.io
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#pragma once
+
+#include <stddef.h>
+
+namespace WCWrite
+{
+  // Copy from normal cacheable memory into write-combined memory. The source
+  // and destination ranges must not overlap. Call Flush before publishing the
+  // written range to another processor or device.
+  void Copy(void * destination, const void * source, size_t size);
+  void Flush();
+}