Nt32Pkg/MonotonicCounterRuntimeDxe/Metronome.c

   1 /*++
   2
   3 Copyright (c) 2006, Intel Corporation
   4 All rights reserved. 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 //
  23 // Include common header file for this module.
  24 //
  25 #include "CommonHeader.h"
  26
  27 #include "Metronome.h"
  28
  29 //
  30 // Global Variables
  31 //
  32 EFI_METRONOME_ARCH_PROTOCOL mMetronome = {
  33   WinNtMetronomeDriverWaitForTick,
  34   TICK_PERIOD
  35 };
  36
  37 //
  38 // Worker Functions
  39 //
  40
  41 EFI_STATUS
  42 EFIAPI
  43 WinNtMetronomeDriverWaitForTick (
  44   IN EFI_METRONOME_ARCH_PROTOCOL  *This,
  45   IN UINT32                       TickNumber
  46   )
  47 /*++
  48
  49 Routine Description:
  50
  51   The WaitForTick() function waits for the number of ticks specified by
  52   TickNumber from a known time source in the platform.  If TickNumber of
  53   ticks are detected, then EFI_SUCCESS is returned.  The actual time passed
  54   between entry of this function and the first tick is between 0 and
  55   TickPeriod 100 nS units.  If you want to guarantee that at least TickPeriod
  56   time has elapsed, wait for two ticks.  This function waits for a hardware
  57   event to determine when a tick occurs.  It is possible for interrupt
  58   processing, or exception processing to interrupt the execution of the
  59   WaitForTick() function.  Depending on the hardware source for the ticks, it
  60   is possible for a tick to be missed.  This function cannot guarantee that
  61   ticks will not be missed.  If a timeout occurs waiting for the specified
  62   number of ticks, then EFI_TIMEOUT is returned.
  63
  64 Arguments:
  65
  66   This       - The EFI_METRONOME_ARCH_PROTOCOL instance.
  67   TickNumber - Number of ticks to wait.
  68
  69 Returns:
  70
  71   EFI_SUCCESS - The wait for the number of ticks specified by TickNumber
  72                 succeeded.
  73
  74 --*/
  75 {
  76   UINT64  SleepTime;
  77
  78   //
  79   // Calculate the time to sleep.  Win API smallest unit to sleep is 1 millisec
  80   // Tick Period is in 100ns units, divide by 10000 to convert to ms
  81   //
  82   SleepTime = DivU64x32 (MultU64x32 ((UINT64) TickNumber, TICK_PERIOD) + 9999, 10000);
  83   gWinNt->Sleep ((UINT32) SleepTime);
  84
  85   return EFI_SUCCESS;
  86 }
  87
  88
  89 EFI_STATUS
  90 EFIAPI
  91 WinNtMetronomeDriverInitialize (
  92   IN EFI_HANDLE        ImageHandle,
  93   IN EFI_SYSTEM_TABLE  *SystemTable
  94   )
  95 /*++
  96
  97 Routine Description:
  98
  99   Initialize the Metronome Architectural Protocol driver
 100
 101 Arguments:
 102
 103   ImageHandle - ImageHandle of the loaded driver
 104
 105
 106   SystemTable - Pointer to the System Table
 107
 108 Returns:
 109
 110   EFI_SUCCESS           - Metronome Architectural Protocol created
 111
 112   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 113
 114   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
 115
 116 --*/
 117 {
 118   EFI_STATUS  Status;
 119   EFI_HANDLE  Handle;
 120
 121
 122   //
 123   // Install the Metronome Architectural Protocol onto a new handle
 124   //
 125   Handle = NULL;
 126   Status = gBS->InstallProtocolInterface (
 127                   &Handle,
 128                   &gEfiMetronomeArchProtocolGuid,
 129                   EFI_NATIVE_INTERFACE,
 130                   &mMetronome
 131                   );
 132
 133   return Status;
 134 }