Nt32Pkg/MetronomeDxe/Metronome.c

   1 /**@file
   2
   3 Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
   4 SPDX-License-Identifier: BSD-2-Clause-Patent
   5
   6 Module Name:
   7
   8   Metronome.c
   9
  10 Abstract:
  11
  12   NT Emulation Metronome Architectural Protocol Driver as defined in DXE CIS
  13
  14 **/
  15
  16 #include "Metronome.h"
  17
  18 //
  19 // Global Variables
  20 //
  21 EFI_METRONOME_ARCH_PROTOCOL mMetronome = {
  22   WinNtMetronomeDriverWaitForTick,
  23   TICK_PERIOD
  24 };
  25
  26 //
  27 // Worker Functions
  28 //
  29
  30 EFI_STATUS
  31 EFIAPI
  32 WinNtMetronomeDriverWaitForTick (
  33   IN EFI_METRONOME_ARCH_PROTOCOL  *This,
  34   IN UINT32                       TickNumber
  35   )
  36 /*++
  37
  38 Routine Description:
  39
  40   The WaitForTick() function waits for the number of ticks specified by
  41   TickNumber from a known time source in the platform.  If TickNumber of
  42   ticks are detected, then EFI_SUCCESS is returned.  The actual time passed
  43   between entry of this function and the first tick is between 0 and
  44   TickPeriod 100 nS units.  If you want to guarantee that at least TickPeriod
  45   time has elapsed, wait for two ticks.  This function waits for a hardware
  46   event to determine when a tick occurs.  It is possible for interrupt
  47   processing, or exception processing to interrupt the execution of the
  48   WaitForTick() function.  Depending on the hardware source for the ticks, it
  49   is possible for a tick to be missed.  This function cannot guarantee that
  50   ticks will not be missed.  If a timeout occurs waiting for the specified
  51   number of ticks, then EFI_TIMEOUT is returned.
  52
  53 Arguments:
  54
  55   This       - The EFI_METRONOME_ARCH_PROTOCOL instance.
  56   TickNumber - Number of ticks to wait.
  57
  58 Returns:
  59
  60   EFI_SUCCESS - The wait for the number of ticks specified by TickNumber
  61                 succeeded.
  62
  63 --*/
  64 {
  65   UINT64  SleepTime;
  66
  67   //
  68   // Calculate the time to sleep.  Win API smallest unit to sleep is 1 millisec
  69   // Tick Period is in 100ns units, divide by 10000 to convert to ms
  70   //
  71   SleepTime = DivU64x32 (MultU64x32 ((UINT64) TickNumber, TICK_PERIOD) + 9999, 10000);
  72   gWinNt->Sleep ((UINT32) SleepTime);
  73
  74   return EFI_SUCCESS;
  75 }
  76
  77
  78 EFI_STATUS
  79 EFIAPI
  80 WinNtMetronomeDriverInitialize (
  81   IN EFI_HANDLE        ImageHandle,
  82   IN EFI_SYSTEM_TABLE  *SystemTable
  83   )
  84 /*++
  85
  86 Routine Description:
  87
  88   Initialize the Metronome Architectural Protocol driver
  89
  90 Arguments:
  91
  92   ImageHandle - ImageHandle of the loaded driver
  93
  94
  95   SystemTable - Pointer to the System Table
  96
  97 Returns:
  98
  99   EFI_SUCCESS           - Metronome Architectural Protocol created
 100
 101   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 102
 103   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
 104
 105 --*/
 106 {
 107   EFI_STATUS  Status;
 108   EFI_HANDLE  Handle;
 109
 110
 111   //
 112   // Install the Metronome Architectural Protocol onto a new handle
 113   //
 114   Handle = NULL;
 115   Status = gBS->InstallProtocolInterface (
 116                   &Handle,
 117                   &gEfiMetronomeArchProtocolGuid,
 118                   EFI_NATIVE_INTERFACE,
 119                   &mMetronome
 120                   );
 121
 122   return Status;
 123 }