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 EFIAPI
  28 ResetPowerManagementFeature (
  29   IN PCI_IO_DEVICE *PciIoDevice
  30   )
  31 /*++
  32
  33 Routine Description:
  34
  35   This function is intended to turn off PWE assertion and
  36   put the device to D0 state if the device supports
  37   PCI Power Management.
  38
  39 Arguments:
  40
  41 Returns:
  42
  43   None
  44
  45 --*/
  46 {
  47   EFI_STATUS  Status;
  48   UINT8       PowerManagementRegBlock;
  49   UINT16      PMCSR;
  50
  51   PowerManagementRegBlock = 0;
  52
  53   Status = LocateCapabilityRegBlock (
  54             PciIoDevice,
  55             EFI_PCI_CAPABILITY_ID_PMI,
  56             &PowerManagementRegBlock,
  57             NULL
  58             );
  59
  60   if (EFI_ERROR (Status)) {
  61     return EFI_UNSUPPORTED;
  62   }
  63
  64   //
  65   // Turn off the PWE assertion and put the device into D0 State
  66   //
  67   PMCSR = 0x8000;
  68
  69   //
  70   // Write PMCSR
  71   //
  72   PciIoDevice->PciIo.Pci.Write (
  73                           &PciIoDevice->PciIo,
  74                           EfiPciIoWidthUint16,
  75                           PowerManagementRegBlock + 4,
  76                           1,
  77                           &PMCSR
  78                           );
  79
  80   return EFI_SUCCESS;
  81 }