IntelFrameworkModulePkg/Bus/Pci/PciBus/Dxe/PciPowerManagement.c

   1 /*++
   2
   3 Copyright (c) 2006 - 2007, 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 // TODO:    PciIoDevice - add argument and description to function comment
  46 // TODO:    EFI_UNSUPPORTED - add return value to function comment
  47 // TODO:    EFI_SUCCESS - add return value to function comment
  48 {
  49   EFI_STATUS  Status;
  50   UINT8       PowerManagementRegBlock;
  51   UINT16      PMCSR;
  52
  53   PowerManagementRegBlock = 0;
  54
  55   Status = LocateCapabilityRegBlock (
  56             PciIoDevice,
  57             EFI_PCI_CAPABILITY_ID_PMI,
  58             &PowerManagementRegBlock,
  59             NULL
  60             );
  61
  62   if (EFI_ERROR (Status)) {
  63     return EFI_UNSUPPORTED;
  64   }
  65
  66   //
  67   // Turn off the PWE assertion and put the device into D0 State
  68   //
  69   PMCSR = 0x8000;
  70
  71   //
  72   // Write PMCSR
  73   //
  74   PciIoWrite (
  75                &PciIoDevice->PciIo,
  76                EfiPciIoWidthUint16,
  77                PowerManagementRegBlock + 4,
  78                1,
  79                &PMCSR
  80              );
  81
  82   return EFI_SUCCESS;
  83 }