ArmVirtPkg/FdtParser: avoid unaligned accesses with the MMU off

[mirror_edk2.git] / ArmVirtPkg / Library / ArmXenRelocatablePlatformLib / FdtParser.c

/*\r
 * Copyright (c) 2015, Linaro Ltd. All rights reserved.\r
 *\r
 * This program and the accompanying materials\r
 * are licensed and made available under the terms and conditions of the BSD License\r
 * which accompanies this distribution.  The full text of the license may be found at\r
 * http://opensource.org/licenses/bsd-license.php\r
 *\r
 * THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
 * WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
 */\r
\r
#include <Uefi.h>\r
#include <Include/libfdt.h>\r
\r
BOOLEAN\r
FindMemnode (\r
  IN  VOID    *DeviceTreeBlob,\r
  OUT UINT64  *SystemMemoryBase,\r
  OUT UINT64  *SystemMemorySize\r
  )\r
{\r
  INT32         MemoryNode;\r
  INT32         AddressCells;\r
  INT32         SizeCells;\r
  INT32         Length;\r
  CONST INT32   *Prop;\r
\r
  if (fdt_check_header (DeviceTreeBlob) != 0) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // Look for a node called "memory" at the lowest level of the tree\r
  //\r
  MemoryNode = fdt_path_offset (DeviceTreeBlob, "/memory");\r
  if (MemoryNode <= 0) {\r
    return FALSE;\r
  }\r
\r
  //\r
  // Retrieve the #address-cells and #size-cells properties\r
  // from the root node, or use the default if not provided.\r
  //\r
  AddressCells = 1;\r
  SizeCells = 1;\r
\r
  Prop = fdt_getprop (DeviceTreeBlob, 0, "#address-cells", &Length);\r
  if (Length == 4) {\r
    AddressCells = fdt32_to_cpu (*Prop);\r
  }\r
\r
  Prop = fdt_getprop (DeviceTreeBlob, 0, "#size-cells", &Length);\r
  if (Length == 4) {\r
    SizeCells = fdt32_to_cpu (*Prop);\r
  }\r
\r
  //\r
  // Now find the 'reg' property of the /memory node, and read the first\r
  // range listed.\r
  //\r
  Prop = fdt_getprop (DeviceTreeBlob, MemoryNode, "reg", &Length);\r
\r
  if (Length < (AddressCells + SizeCells) * sizeof (INT32)) {\r
    return FALSE;\r
  }\r
\r
  *SystemMemoryBase = fdt32_to_cpu (Prop[0]);\r
  if (AddressCells > 1) {\r
    *SystemMemoryBase = (*SystemMemoryBase << 32) | fdt32_to_cpu (Prop[1]);\r
  }\r
  Prop += AddressCells;\r
\r
  *SystemMemorySize = fdt32_to_cpu (Prop[0]);\r
  if (SizeCells > 1) {\r
    *SystemMemorySize = (*SystemMemorySize << 32) | fdt32_to_cpu (Prop[1]);\r
  }\r
\r
  return TRUE;\r
}\r
\r
VOID\r
CopyFdt (\r
  IN    VOID    *FdtDest,\r
  IN    VOID    *FdtSource\r
  )\r
{\r
  CopyMem (FdtDest, FdtSource, fdt_totalsize (FdtSource));\r
}\r