1 /** @file 2 Provide constructor and GetTick for Dxe instance of ACPI Timer Library 3 4 Copyright (C) 2014, Gabriel L. Somlo <somlo (at) cmu.edu> 5 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 10 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. 13 **/ 14 15 #include <Library/DebugLib.h> 16 #include <Library/IoLib.h> 17 #include <Library/PcdLib.h> 18 #include <Library/PciLib.h> 19 #include <OvmfPlatforms.h> 20 21 // 22 // Cached ACPI Timer IO Address 23 // 24 STATIC UINT32 mAcpiTimerIoAddr; 25 26 /** 27 The constructor function caches the ACPI tick counter address 28 29 At the time this constructor runs (DXE_CORE or later), ACPI IO space 30 has already been enabled by either PlatformPei or by the "Base" 31 instance of this library. 32 In order to avoid querying the underlying platform type during each 33 tick counter read operation, we cache the counter address during 34 initialization of this instance of the Timer Library. 35 36 @retval EFI_SUCCESS The constructor always returns RETURN_SUCCESS. 37 38 **/ 39 RETURN_STATUS 40 EFIAPI 41 AcpiTimerLibConstructor ( 42 VOID 43 ) 44 { 45 UINT16 HostBridgeDevId; 46 UINTN Pmba; 47 48 // 49 // Query Host Bridge DID to determine platform type 50 // 51 HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId); 52 switch (HostBridgeDevId) { 53 case INTEL_82441_DEVICE_ID: 54 Pmba = POWER_MGMT_REGISTER_PIIX4 (PIIX4_PMBA); 55 break; 56 case INTEL_Q35_MCH_DEVICE_ID: 57 Pmba = POWER_MGMT_REGISTER_Q35 (ICH9_PMBASE); 58 break; 59 default: 60 DEBUG ((EFI_D_ERROR, "%a: Unknown Host Bridge Device ID: 0x%04x\n", 61 __FUNCTION__, HostBridgeDevId)); 62 ASSERT (FALSE); 63 return RETURN_UNSUPPORTED; 64 } 65 66 mAcpiTimerIoAddr = (PciRead32 (Pmba) & ~PMBA_RTE) + ACPI_TIMER_OFFSET; 67 68 return RETURN_SUCCESS; 69 } 70 71 /** 72 Internal function to read the current tick counter of ACPI. 73 74 Read the current ACPI tick counter using the counter address cached 75 by this instance's constructor. 76 77 @return The tick counter read. 78 79 **/ 80 UINT32 81 InternalAcpiGetTimerTick ( 82 VOID 83 ) 84 { 85 // 86 // Return the current ACPI timer value. 87 // 88 return IoRead32 (mAcpiTimerIoAddr); 89 } 90
