EdkUnixPkg/Dxe/UnixThunk/Chipset/Metronome/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 #include "Metronome.h"
  23
  24 //
  25 // Global Variables
  26 //
  27 EFI_METRONOME_ARCH_PROTOCOL mMetronome = {
  28   UnixMetronomeDriverWaitForTick,
  29   TICK_PERIOD
  30 };
  31
  32 //
  33 // Worker Functions
  34 //
  35
  36 EFI_STATUS
  37 EFIAPI
  38 UnixMetronomeDriverWaitForTick (
  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   gUnix->Sleep ((UINT32) SleepTime);
  79
  80   return EFI_SUCCESS;
  81 }
  82
  83
  84 EFI_STATUS
  85 EFIAPI
  86 UnixMetronomeDriverInitialize (
  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 }