InOsEmuPkg/MetronomeDxe/Metronome.c

   1 /*++ @file
   2   Emu Emulation Metronome Architectural Protocol Driver as defined in DXE CIS
   3
   4 Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   5 Portions copyright (c) 2010 - 2011, Apple Inc. All rights reserved.
   6 This program and the accompanying materials
   7 are licensed and made available under the terms and conditions of the BSD License
   8 which accompanies this distribution.  The full text of the license may be found at
   9 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 **/
  16
  17 #include "Metronome.h"
  18
  19
  20 //
  21 // Global Variables
  22 //
  23 EFI_METRONOME_ARCH_PROTOCOL mMetronome = {
  24   EmuMetronomeDriverWaitForTick,
  25   TICK_PERIOD
  26 };
  27
  28 //
  29 // Worker Functions
  30 //
  31
  32 EFI_STATUS
  33 EFIAPI
  34 EmuMetronomeDriverWaitForTick (
  35   IN EFI_METRONOME_ARCH_PROTOCOL  *This,
  36   IN UINT32                       TickNumber
  37   )
  38 /*++
  39
  40 Routine Description:
  41
  42   The WaitForTick() function waits for the number of ticks specified by
  43   TickNumber from a known time source in the platform.  If TickNumber of
  44   ticks are detected, then EFI_SUCCESS is returned.  The actual time passed
  45   between entry of this function and the first tick is between 0 and
  46   TickPeriod 100 nS units.  If you want to guarantee that at least TickPeriod
  47   time has elapsed, wait for two ticks.  This function waits for a hardware
  48   event to determine when a tick occurs.  It is possible for interrupt
  49   processing, or exception processing to interrupt the execution of the
  50   WaitForTick() function.  Depending on the hardware source for the ticks, it
  51   is possible for a tick to be missed.  This function cannot guarantee that
  52   ticks will not be missed.  If a timeout occurs waiting for the specified
  53   number of ticks, then EFI_TIMEOUT is returned.
  54
  55 Arguments:
  56
  57   This       - The EFI_METRONOME_ARCH_PROTOCOL instance.
  58   TickNumber - Number of ticks to wait.
  59
  60 Returns:
  61
  62   EFI_SUCCESS - The wait for the number of ticks specified by TickNumber
  63                 succeeded.
  64
  65 **/
  66 {
  67   UINT64  SleepTime;
  68
  69   //
  70   // Calculate the time to sleep.  Emu smallest unit to sleep is 1 millisec
  71   // Tick Period is in 100ns units, divide by 10000 to convert to ms
  72   //
  73   SleepTime = DivU64x32 (MultU64x32 ((UINT64) TickNumber, TICK_PERIOD) + 9999, 10000);
  74   gEmuThunk->Sleep (SleepTime);
  75
  76   return EFI_SUCCESS;
  77 }
  78
  79
  80 EFI_STATUS
  81 EFIAPI
  82 EmuMetronomeDriverInitialize (
  83   IN EFI_HANDLE        ImageHandle,
  84   IN EFI_SYSTEM_TABLE  *SystemTable
  85   )
  86 /*++
  87
  88 Routine Description:
  89
  90   Initialize the Metronome Architectural Protocol driver
  91
  92 Arguments:
  93
  94   ImageHandle - ImageHandle of the loaded driver
  95
  96
  97   SystemTable - Pointer to the System Table
  98
  99 Returns:
 100
 101   EFI_SUCCESS           - Metronome Architectural Protocol created
 102
 103   EFI_OUT_OF_RESOURCES  - Not enough resources available to initialize driver.
 104
 105   EFI_DEVICE_ERROR      - A device error occured attempting to initialize the driver.
 106
 107 **/
 108 {
 109   EFI_STATUS  Status;
 110   EFI_HANDLE  Handle;
 111
 112
 113   //
 114   // Install the Metronome Architectural Protocol onto a new handle
 115   //
 116   Handle = NULL;
 117   Status = gBS->InstallProtocolInterface (
 118                   &Handle,
 119                   &gEfiMetronomeArchProtocolGuid,
 120                   EFI_NATIVE_INTERFACE,
 121                   &mMetronome
 122                   );
 123
 124   return Status;
 125 }