historical/m0-applesillicon.git/xnu-qemu-arm64-5.1.0/roms/edk2/OvmfPkg/Library/QemuFwCfgS3Lib/QemuFwCfgS3PeiDxe.c
2024-01-16 11:20:27 -06:00

42 lines
1.2 KiB
C

/** @file
Shared code for the PEI fw_cfg and DXE fw_cfg instances of the QemuFwCfgS3Lib
class.
Copyright (C) 2017, Red Hat, Inc.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <Library/QemuFwCfgLib.h>
#include <Library/QemuFwCfgS3Lib.h>
/**
Determine if S3 support is explicitly enabled.
@retval TRUE If S3 support is explicitly enabled. Other functions in this
library may be called (subject to their individual
restrictions).
FALSE Otherwise. This includes unavailability of the firmware
configuration interface. No other function in this library
must be called.
**/
BOOLEAN
EFIAPI
QemuFwCfgS3Enabled (
VOID
)
{
RETURN_STATUS Status;
FIRMWARE_CONFIG_ITEM FwCfgItem;
UINTN FwCfgSize;
UINT8 SystemStates[6];
Status = QemuFwCfgFindFile ("etc/system-states", &FwCfgItem, &FwCfgSize);
if (Status != RETURN_SUCCESS || FwCfgSize != sizeof SystemStates) {
return FALSE;
}
QemuFwCfgSelectItem (FwCfgItem);
QemuFwCfgReadBytes (sizeof SystemStates, SystemStates);
return (BOOLEAN) (SystemStates[3] & BIT7);
}