/**
This function is intended to turn off PWE assertion and
put the device to D0 state if the device supports
PCI Power Management.
@param PciIoDevice PCI device instance.
@retval EFI_UNSUPPORTED PCI Device does not support power management.
@retval EFI_SUCCESS Turned off PWE successfully.
**/
EFI_STATUS
ResetPowerManagementFeature (
IN PCI_IO_DEVICE *PciIoDevice
)
{
EFI_STATUS Status;
UINT8 PowerManagementRegBlock;
UINT16 PowerManagementCSR;
PowerManagementRegBlock = 0;
Status = LocateCapabilityRegBlock (
PciIoDevice,
EFI_PCI_CAPABILITY_ID_PMI,
&PowerManagementRegBlock,
NULL
);
if (EFI_ERROR (Status)) {
return EFI_UNSUPPORTED;
}
//
// Turn off the PWE assertion and put the device into D0 State
//
PowerManagementCSR = 0x8000;
//
// Write PMCSR
//
PciIoDevice->PciIo.Pci.Write (
&PciIoDevice->PciIo,
EfiPciIoWidthUint16,
PowerManagementRegBlock + 4,
1,
&PowerManagementCSR
);
return EFI_SUCCESS;
}
EFI_STATUS
EFIAPI
ResetPowerManagementFeature (
IN PCI_IO_DEVICE *PciIoDevice
)
/*++
Routine Description:
This function is intended to turn off PWE assertion and
put the device to D0 state if the device supports
PCI Power Management.
Arguments:
Returns:
None
--*/
{
EFI_STATUS Status;
UINT8 PowerManagementRegBlock;
UINT16 PowerManagementCSR;
PowerManagementRegBlock = 0;
Status = LocateCapabilityRegBlock (
PciIoDevice,
EFI_PCI_CAPABILITY_ID_PMI,
&PowerManagementRegBlock,
NULL
);
if (EFI_ERROR (Status)) {
return EFI_UNSUPPORTED;
}
//
// Turn off the PWE assertion and put the device into D0 State
//
//
// Read PMCSR
//
Status = PciIoDevice->PciIo.Pci.Read (
&PciIoDevice->PciIo,
EfiPciIoWidthUint16,
PowerManagementRegBlock + 4,
1,
&PowerManagementCSR
);
if (!EFI_ERROR (Status)) {
//
// Clear PME_Status bit
//
PowerManagementCSR |= BIT15;
//
// Clear PME_En bit. PowerState = D0.
//
PowerManagementCSR &= ~(BIT8 | BIT1 | BIT0);
//
// Write PMCSR
//
Status = PciIoDevice->PciIo.Pci.Write (
&PciIoDevice->PciIo,
EfiPciIoWidthUint16,
PowerManagementRegBlock + 4,
1,
&PowerManagementCSR
);
}
return Status;
}
