1 /**@file 2 3 Copyright (c) 2006, Intel Corporation. All rights reserved.<BR> 4 This program and the accompanying materials 5 are licensed and made available under the terms and conditions of the BSD License 6 which accompanies this distribution. The full text of the license may be found at 7 http://opensource.org/licenses/bsd-license.php 8 9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 12 Module Name: 13 14 Metronome.c 15 16 Abstract: 17 18 NT Emulation Metronome Architectural Protocol Driver as defined in DXE CIS 19 20 **/ 21 22 #include "Metronome.h" 23 24 // 25 // Global Variables 26 // 27 EFI_METRONOME_ARCH_PROTOCOL mMetronome = { 28 WinNtMetronomeDriverWaitForTick, 29 TICK_PERIOD 30 }; 31 32 // 33 // Worker Functions 34 // 35 36 EFI_STATUS 37 EFIAPI 38 WinNtMetronomeDriverWaitForTick ( 39 IN EFI_METRONOME_ARCH_PROTOCOL *This, 40 IN UINT32 TickNumber 41 ) 42 /*++ 43 44 Routine Description: 45 46 The WaitForTick() function waits for the number of ticks specified by 47 TickNumber from a known time source in the platform. If TickNumber of 48 ticks are detected, then EFI_SUCCESS is returned. The actual time passed 49 between entry of this function and the first tick is between 0 and 50 TickPeriod 100 nS units. If you want to guarantee that at least TickPeriod 51 time has elapsed, wait for two ticks. This function waits for a hardware 52 event to determine when a tick occurs. It is possible for interrupt 53 processing, or exception processing to interrupt the execution of the 54 WaitForTick() function. Depending on the hardware source for the ticks, it 55 is possible for a tick to be missed. This function cannot guarantee that 56 ticks will not be missed. If a timeout occurs waiting for the specified 57 number of ticks, then EFI_TIMEOUT is returned. 58 59 Arguments: 60 61 This - The EFI_METRONOME_ARCH_PROTOCOL instance. 62 TickNumber - Number of ticks to wait. 63 64 Returns: 65 66 EFI_SUCCESS - The wait for the number of ticks specified by TickNumber 67 succeeded. 68 69 --*/ 70 { 71 UINT64 SleepTime; 72 73 // 74 // Calculate the time to sleep. Win API smallest unit to sleep is 1 millisec 75 // Tick Period is in 100ns units, divide by 10000 to convert to ms 76 // 77 SleepTime = DivU64x32 (MultU64x32 ((UINT64) TickNumber, TICK_PERIOD) + 9999, 10000); 78 gWinNt->Sleep ((UINT32) SleepTime); 79 80 return EFI_SUCCESS; 81 } 82 83 84 EFI_STATUS 85 EFIAPI 86 WinNtMetronomeDriverInitialize ( 87 IN EFI_HANDLE ImageHandle, 88 IN EFI_SYSTEM_TABLE *SystemTable 89 ) 90 /*++ 91 92 Routine Description: 93 94 Initialize the Metronome Architectural Protocol driver 95 96 Arguments: 97 98 ImageHandle - ImageHandle of the loaded driver 99 100 101 SystemTable - Pointer to the System Table 102 103 Returns: 104 105 EFI_SUCCESS - Metronome Architectural Protocol created 106 107 EFI_OUT_OF_RESOURCES - Not enough resources available to initialize driver. 108 109 EFI_DEVICE_ERROR - A device error occured attempting to initialize the driver. 110 111 --*/ 112 { 113 EFI_STATUS Status; 114 EFI_HANDLE Handle; 115 116 117 // 118 // Install the Metronome Architectural Protocol onto a new handle 119 // 120 Handle = NULL; 121 Status = gBS->InstallProtocolInterface ( 122 &Handle, 123 &gEfiMetronomeArchProtocolGuid, 124 EFI_NATIVE_INTERFACE, 125 &mMetronome 126 ); 127 128 return Status; 129 } 130
