| Vishal Bhoj | 82c8071 | 2015-12-15 21:13:33 +0530 | [diff] [blame^] | 1 | /** @file
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| 2 | Provide constructor and GetTick for Dxe instance of ACPI Timer Library
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| 3 |
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| 4 | Copyright (C) 2014, Gabriel L. Somlo <somlo@cmu.edu>
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| 5 |
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| 6 | This program and the accompanying materials are licensed and made
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| 7 | available under the terms and conditions of the BSD License which
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| 8 | accompanies this distribution. The full text of the license may
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| 9 | be found at http://opensource.org/licenses/bsd-license.php
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| 10 |
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| 11 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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| 12 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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| 13 | **/
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| 14 |
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| 15 | #include <Library/DebugLib.h>
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| 16 | #include <Library/IoLib.h>
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| 17 | #include <Library/PcdLib.h>
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| 18 | #include <Library/PciLib.h>
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| 19 | #include <OvmfPlatforms.h>
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| 20 |
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| 21 | //
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| 22 | // Power Management PCI Configuration Register fields
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| 23 | //
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| 24 | #define PMBA_RTE BIT0
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| 25 |
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| 26 | //
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| 27 | // Offset in the Power Management Base Address to the ACPI Timer
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| 28 | //
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| 29 | #define ACPI_TIMER_OFFSET 0x8
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| 30 |
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| 31 | //
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| 32 | // Cached ACPI Timer IO Address
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| 33 | //
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| 34 | STATIC UINT32 mAcpiTimerIoAddr;
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| 35 |
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| 36 | /**
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| 37 | The constructor function caches the ACPI tick counter address
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| 38 |
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| 39 | At the time this constructor runs (DXE_CORE or later), ACPI IO space
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| 40 | has already been enabled by either PlatformPei or by the "Base"
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| 41 | instance of this library.
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| 42 | In order to avoid querying the underlying platform type during each
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| 43 | tick counter read operation, we cache the counter address during
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| 44 | initialization of this instance of the Timer Library.
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| 45 |
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| 46 | @retval EFI_SUCCESS The constructor always returns RETURN_SUCCESS.
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| 47 |
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| 48 | **/
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| 49 | RETURN_STATUS
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| 50 | EFIAPI
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| 51 | AcpiTimerLibConstructor (
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| 52 | VOID
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| 53 | )
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| 54 | {
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| 55 | UINT16 HostBridgeDevId;
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| 56 | UINTN Pmba;
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| 57 |
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| 58 | //
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| 59 | // Query Host Bridge DID to determine platform type
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| 60 | //
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| 61 | HostBridgeDevId = PcdGet16 (PcdOvmfHostBridgePciDevId);
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| 62 | switch (HostBridgeDevId) {
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| 63 | case INTEL_82441_DEVICE_ID:
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| 64 | Pmba = POWER_MGMT_REGISTER_PIIX4 (0x40);
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| 65 | break;
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| 66 | case INTEL_Q35_MCH_DEVICE_ID:
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| 67 | Pmba = POWER_MGMT_REGISTER_Q35 (0x40);
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| 68 | break;
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| 69 | default:
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| 70 | DEBUG ((EFI_D_ERROR, "%a: Unknown Host Bridge Device ID: 0x%04x\n",
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| 71 | __FUNCTION__, HostBridgeDevId));
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| 72 | ASSERT (FALSE);
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| 73 | return RETURN_UNSUPPORTED;
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| 74 | }
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| 75 |
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| 76 | mAcpiTimerIoAddr = (PciRead32 (Pmba) & ~PMBA_RTE) + ACPI_TIMER_OFFSET;
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| 77 |
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| 78 | return RETURN_SUCCESS;
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| 79 | }
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| 80 |
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| 81 | /**
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| 82 | Internal function to read the current tick counter of ACPI.
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| 83 |
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| 84 | Read the current ACPI tick counter using the counter address cached
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| 85 | by this instance's constructor.
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| 86 |
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| 87 | @return The tick counter read.
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| 88 |
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| 89 | **/
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| 90 | UINT32
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| 91 | InternalAcpiGetTimerTick (
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| 92 | VOID
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| 93 | )
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| 94 | {
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| 95 | //
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| 96 | // Return the current ACPI timer value.
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| 97 | //
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| 98 | return IoRead32 (mAcpiTimerIoAddr);
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| 99 | }
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