2 Provide constructor and GetTick for Base instance of ACPI Timer Library
4 Copyright (C) 2014, Gabriel L. Somlo <somlo@cmu.edu>
6 This program and the accompanying materials are licensed and made
7 available under the terms and conditions of the BSD License which
8 accompanies this distribution. The full text of the license may
9 be found at http://opensource.org/licenses/bsd-license.php
11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
15 #include <Library/DebugLib.h>
16 #include <Library/IoLib.h>
17 #include <Library/PciLib.h>
18 #include <OvmfPlatforms.h>
21 // Cached ACPI Timer IO Address
23 STATIC UINT32 mAcpiTimerIoAddr
;
26 The constructor function caches the ACPI tick counter address, and,
27 if necessary, enables ACPI IO space.
29 @retval EFI_SUCCESS The constructor always returns RETURN_SUCCESS.
34 AcpiTimerLibConstructor (
38 UINT16 HostBridgeDevId
;
44 // Query Host Bridge DID to determine platform type
46 HostBridgeDevId
= PciRead16 (OVMF_HOSTBRIDGE_DID
);
47 switch (HostBridgeDevId
) {
48 case INTEL_82441_DEVICE_ID
:
49 Pmba
= POWER_MGMT_REGISTER_PIIX4 (PIIX4_PMBA
);
50 AcpiCtlReg
= POWER_MGMT_REGISTER_PIIX4 (PIIX4_PMREGMISC
);
51 AcpiEnBit
= PIIX4_PMREGMISC_PMIOSE
;
53 case INTEL_Q35_MCH_DEVICE_ID
:
54 Pmba
= POWER_MGMT_REGISTER_Q35 (ICH9_PMBASE
);
55 AcpiCtlReg
= POWER_MGMT_REGISTER_Q35 (ICH9_ACPI_CNTL
);
56 AcpiEnBit
= ICH9_ACPI_CNTL_ACPI_EN
;
59 DEBUG ((EFI_D_ERROR
, "%a: Unknown Host Bridge Device ID: 0x%04x\n",
60 __FUNCTION__
, HostBridgeDevId
));
62 return RETURN_UNSUPPORTED
;
66 // Check to see if the Power Management Base Address is already enabled
68 if ((PciRead8 (AcpiCtlReg
) & AcpiEnBit
) == 0) {
70 // If the Power Management Base Address is not programmed,
71 // then program it now.
73 PciAndThenOr32 (Pmba
, (UINT32
) ~0xFFC0, PIIX4_PMBA_VALUE
);
76 // Enable PMBA I/O port decodes
78 PciOr8 (AcpiCtlReg
, AcpiEnBit
);
81 mAcpiTimerIoAddr
= (PciRead32 (Pmba
) & ~PMBA_RTE
) + ACPI_TIMER_OFFSET
;
82 return RETURN_SUCCESS
;
86 Internal function to read the current tick counter of ACPI.
88 Read the current ACPI tick counter using the counter address cached
89 by this instance's constructor.
91 @return The tick counter read.
95 InternalAcpiGetTimerTick (
100 // Return the current ACPI timer value.
102 return IoRead32 (mAcpiTimerIoAddr
);