DuetPkg/PciBusNoEnumerationDxe/PciPowerManagement.c

   1 /*++
   2
   3 Copyright (c) 2005 - 2012, Intel Corporation. All rights reserved.<BR>
   4 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      PowerManagementCSR;
  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
  68   //
  69   // Read PMCSR
  70   //
  71   Status = PciIoDevice->PciIo.Pci.Read (
  72                                     &PciIoDevice->PciIo,
  73                                     EfiPciIoWidthUint16,
  74                                     PowerManagementRegBlock + 4,
  75                                     1,
  76                                     &PowerManagementCSR
  77                                     );
  78   if (!EFI_ERROR (Status)) {
  79     //
  80     // Clear PME_Status bit
  81     //
  82     PowerManagementCSR |= BIT15;
  83     //
  84     // Clear PME_En bit. PowerState = D0.
  85     //
  86     PowerManagementCSR &= ~(BIT8 | BIT1 | BIT0);
  87
  88     //
  89     // Write PMCSR
  90     //
  91     Status = PciIoDevice->PciIo.Pci.Write (
  92                                       &PciIoDevice->PciIo,
  93                                       EfiPciIoWidthUint16,
  94                                       PowerManagementRegBlock + 4,
  95                                       1,
  96                                       &PowerManagementCSR
  97                                       );
  98   }
  99   return Status;
 100 }