ArmVirtPkg/XenRelocatablePlatformLib: rewrite DTB memory node retrieval in C

Parsing the DTB early on using a handcoded assembly routine is a pointless
waste of brain cycles, since the UEFI firmware always executes from RAM
under Xen. So instead, set up a temporary stack in the memory region at the
beginning of the image, and use the libfdt C library.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19330 6f19259b-4bc3-4df7-8a09-765794883524

ArmVirtPkg/Library/ArmXenRelocatablePlatformLib/FdtParser.c

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2015, Linaro Ltd. All rights reserved.
+ *
+ * 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 <Uefi.h>
+#include <Include/libfdt.h>
+
+BOOLEAN
+FindMemnode (
+  IN  VOID    *DeviceTreeBlob,
+  OUT UINT64  *SystemMemoryBase,
+  OUT UINT64  *SystemMemorySize
+  )
+{
+  INT32         MemoryNode;
+  INT32         AddressCells;
+  INT32         SizeCells;
+  INT32         Length;
+  CONST INT32   *Prop;
+
+  if (fdt_check_header (DeviceTreeBlob) != 0) {
+    return FALSE;
+  }
+
+  //
+  // Look for a node called "memory" at the lowest level of the tree
+  //
+  MemoryNode = fdt_path_offset (DeviceTreeBlob, "/memory");
+  if (MemoryNode <= 0) {
+    return FALSE;
+  }
+
+  //
+  // Retrieve the #address-cells and #size-cells properties
+  // from the root node, or use the default if not provided.
+  //
+  AddressCells = 1;
+  SizeCells = 1;
+
+  Prop = fdt_getprop (DeviceTreeBlob, 0, "#address-cells", &Length);
+  if (Length == 4) {
+    AddressCells = fdt32_to_cpu (*Prop);
+  }
+
+  Prop = fdt_getprop (DeviceTreeBlob, 0, "#size-cells", &Length);
+  if (Length == 4) {
+    SizeCells = fdt32_to_cpu (*Prop);
+  }
+
+  //
+  // Now find the 'reg' property of the /memory node, and read the first
+  // range listed.
+  //
+  Prop = fdt_getprop (DeviceTreeBlob, MemoryNode, "reg", &Length);
+
+  if (Length < (AddressCells + SizeCells) * sizeof (INT32)) {
+    return FALSE;
+  }
+
+  if (AddressCells == 1) {
+    *SystemMemoryBase = fdt32_to_cpu (*Prop);
+  } else {
+    *SystemMemoryBase = fdt64_to_cpu (*(UINT64 *)Prop);
+  }
+  Prop += AddressCells;
+
+  if (SizeCells == 1) {
+    *SystemMemorySize = fdt32_to_cpu (*Prop);
+  } else {
+    *SystemMemorySize = fdt64_to_cpu (*(UINT64 *)Prop);
+  }
+
+  return TRUE;
+}
+
+VOID
+CopyFdt (
+  IN    VOID    *FdtDest,
+  IN    VOID    *FdtSource
+  )
+{
+  CopyMem (FdtDest, FdtSource, fdt_totalsize (FdtSource));
+}