/** @file | |
Power management support functions implementation for PCI Bus module. | |
Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
#include "PciBus.h" | |
/** | |
This function is intended to turn off PWE assertion and | |
put the device to D0 state if the device supports | |
PCI Power Management. | |
@param PciIoDevice PCI device instance. | |
@retval EFI_UNSUPPORTED PCI Device does not support power management. | |
@retval EFI_SUCCESS Turned off PWE successfully. | |
**/ | |
EFI_STATUS | |
ResetPowerManagementFeature ( | |
IN PCI_IO_DEVICE *PciIoDevice | |
) | |
{ | |
EFI_STATUS Status; | |
UINT8 PowerManagementRegBlock; | |
UINT16 PowerManagementCSR; | |
PowerManagementRegBlock = 0; | |
Status = LocateCapabilityRegBlock ( | |
PciIoDevice, | |
EFI_PCI_CAPABILITY_ID_PMI, | |
&PowerManagementRegBlock, | |
NULL | |
); | |
if (EFI_ERROR (Status)) { | |
return EFI_UNSUPPORTED; | |
} | |
// | |
// Turn off the PWE assertion and put the device into D0 State | |
// | |
// | |
// Read PMCSR | |
// | |
Status = PciIoDevice->PciIo.Pci.Read ( | |
&PciIoDevice->PciIo, | |
EfiPciIoWidthUint16, | |
PowerManagementRegBlock + 4, | |
1, | |
&PowerManagementCSR | |
); | |
if (!EFI_ERROR (Status)) { | |
// | |
// Clear PME_Status bit | |
// | |
PowerManagementCSR |= BIT15; | |
// | |
// Clear PME_En bit. PowerState = D0. | |
// | |
PowerManagementCSR &= ~(BIT8 | BIT1 | BIT0); | |
// | |
// Write PMCSR | |
// | |
Status = PciIoDevice->PciIo.Pci.Write ( | |
&PciIoDevice->PciIo, | |
EfiPciIoWidthUint16, | |
PowerManagementRegBlock + 4, | |
1, | |
&PowerManagementCSR | |
); | |
} | |
return Status; | |
} |