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 EFI_STATUS
  17 ResetPowerManagementFeature (
  18   IN PCI_IO_DEVICE *PciIoDevice
  19   )
  20 /**
  21
  22 Routine Description:
  23
  24   This function is intended to turn off PWE assertion and
  25   put the device to D0 state if the device supports
  26   PCI Power Management.
  27
  28 Arguments:
  29
  30 Returns:
  31
  32   None
  33
  34 **/
  35 // TODO:    PciIoDevice - add argument and description to function comment
  36 // TODO:    EFI_UNSUPPORTED - add return value to function comment
  37 // TODO:    EFI_SUCCESS - add return value to function comment
  38 {
  39   EFI_STATUS  Status;
  40   UINT8       PowerManagementRegBlock;
  41   UINT16      PMCSR;
  42
  43   PowerManagementRegBlock = 0;
  44
  45   Status = LocateCapabilityRegBlock (
  46             PciIoDevice,
  47             EFI_PCI_CAPABILITY_ID_PMI,
  48             &PowerManagementRegBlock,
  49             NULL
  50             );
  51
  52   if (EFI_ERROR (Status)) {
  53     return EFI_UNSUPPORTED;
  54   }
  55
  56   //
  57   // Turn off the PWE assertion and put the device into D0 State
  58   //
  59   PMCSR = 0x8000;
  60
  61   //
  62   // Write PMCSR
  63   //
  64   PciIoWrite (
  65                &PciIoDevice->PciIo,
  66                EfiPciIoWidthUint16,
  67                PowerManagementRegBlock + 4,
  68                1,
  69                &PMCSR
  70              );
  71
  72   return EFI_SUCCESS;
  73 }