| /** @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; | |
| } | |