DuetPkg/PciBusNoEnumerationDxe/PciPowerManagement.c

   1 /*++
   2
   3 Copyright (c) 2005 - 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 Module Name:
  13
  14   PciPowerManagement.c
  15
  16 Abstract:
  17
  18   PCI Bus Driver
  19
  20 Revision History
  21
  22 --*/
  23
  24 #include "Pcibus.h"
  25
  26 EFI_STATUS
  27 ResetPowerManagementFeature (
  28   IN PCI_IO_DEVICE *PciIoDevice
  29   )
  30 /*++
  31
  32 Routine Description:
  33
  34   This function is intended to turn off PWE assertion and
  35   put the device to D0 state if the device supports
  36   PCI Power Management.
  37
  38 Arguments:
  39
  40 Returns:
  41
  42   None
  43
  44 --*/
  45 {
  46   EFI_STATUS  Status;
  47   UINT8       PowerManagementRegBlock;
  48   UINT16      PMCSR;
  49
  50   PowerManagementRegBlock = 0;
  51
  52   Status = LocateCapabilityRegBlock (
  53             PciIoDevice,
  54             EFI_PCI_CAPABILITY_ID_PMI,
  55             &PowerManagementRegBlock,
  56             NULL
  57             );
  58
  59   if (EFI_ERROR (Status)) {
  60     return EFI_UNSUPPORTED;
  61   }
  62
  63   //
  64   // Turn off the PWE assertion and put the device into D0 State
  65   //
  66   PMCSR = 0x8000;
  67
  68   //
  69   // Write PMCSR
  70   //
  71   PciIoDevice->PciIo.Pci.Write (
  72                           &PciIoDevice->PciIo,
  73                           EfiPciIoWidthUint16,
  74                           PowerManagementRegBlock + 4,
  75                           1,
  76                           &PMCSR
  77                           );
  78
  79   return EFI_SUCCESS;
  80 }