1 /** @file
2 Power management support fucntions implementation for PCI Bus module.
3
4 Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php
9
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13 **/
14
15 #include "PciBus.h"
16
17 /**
18 This function is intended to turn off PWE assertion and
19 put the device to D0 state if the device supports
20 PCI Power Management.
21
22 @param PciIoDevice PCI device instance.
23
24 @retval EFI_UNSUPPORTED PCI Device does not support power management.
25 @retval EFI_SUCCESS Turned off PWE successfully.
26
27 **/
28 EFI_STATUS
ResetPowerManagementFeature(IN PCI_IO_DEVICE * PciIoDevice)29 ResetPowerManagementFeature (
30 IN PCI_IO_DEVICE *PciIoDevice
31 )
32 {
33 EFI_STATUS Status;
34 UINT8 PowerManagementRegBlock;
35 UINT16 PowerManagementCSR;
36
37 PowerManagementRegBlock = 0;
38
39 Status = LocateCapabilityRegBlock (
40 PciIoDevice,
41 EFI_PCI_CAPABILITY_ID_PMI,
42 &PowerManagementRegBlock,
43 NULL
44 );
45
46 if (EFI_ERROR (Status)) {
47 return EFI_UNSUPPORTED;
48 }
49
50 //
51 // Turn off the PWE assertion and put the device into D0 State
52 //
53
54 //
55 // Read PMCSR
56 //
57 Status = PciIoDevice->PciIo.Pci.Read (
58 &PciIoDevice->PciIo,
59 EfiPciIoWidthUint16,
60 PowerManagementRegBlock + 4,
61 1,
62 &PowerManagementCSR
63 );
64
65 if (!EFI_ERROR (Status)) {
66 //
67 // Clear PME_Status bit
68 //
69 PowerManagementCSR |= BIT15;
70 //
71 // Clear PME_En bit. PowerState = D0.
72 //
73 PowerManagementCSR &= ~(BIT8 | BIT1 | BIT0);
74
75 //
76 // Write PMCSR
77 //
78 Status = PciIoDevice->PciIo.Pci.Write (
79 &PciIoDevice->PciIo,
80 EfiPciIoWidthUint16,
81 PowerManagementRegBlock + 4,
82 1,
83 &PowerManagementCSR
84 );
85 }
86 return Status;
87 }
88
89