audk/FatPkg/FatPei/Part.c

/** @file
  Routines supporting partition discovery and
  logical device reading

Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>

SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#include "FatLitePeim.h"

/**
  This function finds Eltorito partitions. Main algorithm
  is ported from DXE partition driver.

  @param[in]  PrivateData       The global memory map
  @param[in]  ParentBlockDevNo  The parent block device

  @retval TRUE              New partitions are detected and logical block devices
                            are added to block device array
  @retval FALSE             No new partitions are added

**/
BOOLEAN
FatFindEltoritoPartitions (
  IN  PEI_FAT_PRIVATE_DATA *PrivateData,
  IN  UINTN                ParentBlockDevNo
  );

/**
  This function finds Mbr partitions. Main algorithm
  is ported from DXE partition driver.

  @param[in]  PrivateData       The global memory map
  @param[in]  ParentBlockDevNo  The parent block device

  @retval TRUE              New partitions are detected and logical block devices
                            are added to block device array
  @retval FALSE             No new partitions are added

**/
BOOLEAN
FatFindMbrPartitions (
  IN  PEI_FAT_PRIVATE_DATA *PrivateData,
  IN  UINTN                ParentBlockDevNo
  );

/**
  This function is used for finding GPT partition on block device.
  As follow UEFI spec we should check protective MBR first and then
  try to check both primary/backup GPT structures.

  @param[in]  PrivateData       The global memory map
  @param[in]  ParentBlockDevNo  The parent block device

  @retval TRUE              New partitions are detected and logical block devices
                            are added to block device array
  @retval FALSE             No new partitions are added

**/
BOOLEAN
FatFindGptPartitions (
  IN  PEI_FAT_PRIVATE_DATA *PrivateData,
  IN  UINTN                ParentBlockDevNo
  );

/**
  This function finds partitions (logical devices) in physical block devices.

  @param  PrivateData       Global memory map for accessing global variables.

**/
VOID
FatFindPartitions (
  IN  PEI_FAT_PRIVATE_DATA  *PrivateData
  )
{
  BOOLEAN Found;
  UINTN   Index;

  do {
    Found = FALSE;

    for (Index = 0; Index < PrivateData->BlockDeviceCount; Index++) {
      if (!PrivateData->BlockDevice[Index].PartitionChecked) {
        if (FatFindGptPartitions (PrivateData, Index)) {
          Found = TRUE;
          continue;
        }

        if (FatFindMbrPartitions (PrivateData, Index)) {
          Found = TRUE;
          continue;
        }

        if (FatFindEltoritoPartitions (PrivateData, Index)) {
          Found = TRUE;
          continue;
        }
      }
    }
  } while (Found && PrivateData->BlockDeviceCount <= PEI_FAT_MAX_BLOCK_DEVICE);
}