IntelFrameworkModulePkg/Bus/Pci/PciBusDxe/PciPowerManagement.c

   1 /** @file
   2
   3 Copyright (c) 2006, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 **/
  13
  14 #include "PciBus.h"
  15
  16 /**
  17   This function is intended to turn off PWE assertion and
  18   put the device to D0 state if the device supports
  19   PCI Power Management.
  20
  21   @param PciIoDevice  Pci device instance
  22
  23   @retval EFI_UNSUPPORTED Device do not support power management
  24   @retval EFI_SUCCESS     Success
  25 **/
  26 EFI_STATUS
  27 ResetPowerManagementFeature (
  28   IN PCI_IO_DEVICE *PciIoDevice
  29   )
  30 {
  31   EFI_STATUS  Status;
  32   UINT8       PowerManagementRegBlock;
  33   UINT16      PMCSR;
  34
  35   PowerManagementRegBlock = 0;
  36
  37   Status = LocateCapabilityRegBlock (
  38             PciIoDevice,
  39             EFI_PCI_CAPABILITY_ID_PMI,
  40             &PowerManagementRegBlock,
  41             NULL
  42             );
  43
  44   if (EFI_ERROR (Status)) {
  45     return EFI_UNSUPPORTED;
  46   }
  47
  48   //
  49   // Turn off the PWE assertion and put the device into D0 State
  50   //
  51   PMCSR = 0x8000;
  52
  53   //
  54   // Write PMCSR
  55   //
  56   PciIoWrite (
  57                &PciIoDevice->PciIo,
  58                EfiPciIoWidthUint16,
  59                PowerManagementRegBlock + 4,
  60                1,
  61                &PMCSR
  62              );
  63
  64   return EFI_SUCCESS;
  65 }
  66