/** @file

  Copyright (c) 2014-2017, Linaro Limited. 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 <Base.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <libfdt.h>

RETURN_STATUS
EFIAPI
QemuVirtMemInfoPeiLibConstructor (
  VOID
  )
{
  VOID          *DeviceTreeBase;
  INT32         Node, Prev;
  UINT64        NewBase, CurBase;
  UINT64        NewSize, CurSize;
  CONST CHAR8   *Type;
  INT32         Len;
  CONST UINT64  *RegProp;
  RETURN_STATUS PcdStatus;

  NewBase = 0;
  NewSize = 0;

  DeviceTreeBase = (VOID *)(UINTN)PcdGet64 (PcdDeviceTreeInitialBaseAddress);
  ASSERT (DeviceTreeBase != NULL);

  //
  // Make sure we have a valid device tree blob
  //
  ASSERT (fdt_check_header (DeviceTreeBase) == 0);

  //
  // Look for the lowest memory node
  //
  for (Prev = 0;; Prev = Node) {
    Node = fdt_next_node (DeviceTreeBase, Prev, NULL);
    if (Node < 0) {
      break;
    }

    //
    // Check for memory node
    //
    Type = fdt_getprop (DeviceTreeBase, Node, "device_type", &Len);
    if (Type && AsciiStrnCmp (Type, "memory", Len) == 0) {
      //
      // Get the 'reg' property of this node. For now, we will assume
      // two 8 byte quantities for base and size, respectively.
      //
      RegProp = fdt_getprop (DeviceTreeBase, Node, "reg", &Len);
      if (RegProp != 0 && Len == (2 * sizeof (UINT64))) {

        CurBase = fdt64_to_cpu (ReadUnaligned64 (RegProp));
        CurSize = fdt64_to_cpu (ReadUnaligned64 (RegProp + 1));

        DEBUG ((DEBUG_INFO, "%a: System RAM @ 0x%lx - 0x%lx\n",
          __FUNCTION__, CurBase, CurBase + CurSize - 1));

        if (NewBase > CurBase || NewBase == 0) {
          NewBase = CurBase;
          NewSize = CurSize;
        }
      } else {
        DEBUG ((DEBUG_ERROR, "%a: Failed to parse FDT memory node\n",
          __FUNCTION__));
      }
    }
  }

  //
  // Make sure the start of DRAM matches our expectation
  //
  ASSERT (FixedPcdGet64 (PcdSystemMemoryBase) == NewBase);
  PcdStatus = PcdSet64S (PcdSystemMemorySize, NewSize);
  ASSERT_RETURN_ERROR (PcdStatus);

  //
  // We need to make sure that the machine we are running on has at least
  // 128 MB of memory configured, and is currently executing this binary from
  // NOR flash. This prevents a device tree image in DRAM from getting
  // clobbered when our caller installs permanent PEI RAM, before we have a
  // chance of marking its location as reserved or copy it to a freshly
  // allocated block in the permanent PEI RAM in the platform PEIM.
  //
  ASSERT (NewSize >= SIZE_128MB);
  ASSERT (
    (((UINT64)PcdGet64 (PcdFdBaseAddress) +
      (UINT64)PcdGet32 (PcdFdSize)) <= NewBase) ||
    ((UINT64)PcdGet64 (PcdFdBaseAddress) >= (NewBase + NewSize)));

  return RETURN_SUCCESS;
}