DxeTimerLib.c revision bb89ec1a7ec2f8d35033df9e47b3604925da3bd3 
1/** @file
2  A non-functional instance of the Timer Library.
3
4  Copyright (c) 2007 - 2010, Intel Corporation. All rights reserved.<BR>
5  This program and the accompanying materials
6  are licensed and made available under the terms and conditions of the BSD License
7  which accompanies this distribution.  The full text of the license may be found at
8  http://opensource.org/licenses/bsd-license.php.
9
10  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13**/
14
15#include <PiPei.h>
16#include <Library/BaseLib.h>
17#include <Library/TimerLib.h>
18#include <Library/DebugLib.h>
19#include <Library/EmuThunkLib.h>
20#include <Library/UefiBootServicesTableLib.h>
21#include <Library/UefiLib.h>
22
23#include <Protocol/Timer.h>
24
25
26STATIC UINT64                  gTimerPeriod = 0;
27STATIC EFI_TIMER_ARCH_PROTOCOL *gTimerAp = NULL;
28STATIC EFI_EVENT               gTimerEvent = NULL;
29STATIC VOID                    *gRegistration = NULL;
30
31VOID
32EFIAPI
33RegisterTimerArchProtocol (
34  IN EFI_EVENT     Event,
35  IN VOID          *Context
36  )
37{
38  EFI_STATUS  Status;
39
40  Status = gBS->LocateProtocol (&gEfiTimerArchProtocolGuid, NULL, (VOID **)&gTimerAp);
41  if (!EFI_ERROR (Status)) {
42    Status = gTimerAp->GetTimerPeriod (gTimerAp, &gTimerPeriod);
43    ASSERT_EFI_ERROR (Status);
44
45    // Convert to Nanoseconds.
46    gTimerPeriod = MultU64x32 (gTimerPeriod, 100);
47
48    if (gTimerEvent == NULL) {
49      Status = gBS->CreateEvent (EVT_TIMER, 0, NULL, NULL, (VOID **)&gTimerEvent);
50      ASSERT_EFI_ERROR (Status);
51    }
52  }
53}
54
55
56
57/**
58  Stalls the CPU for at least the given number of microseconds.
59
60  Stalls the CPU for the number of microseconds specified by MicroSeconds.
61
62  @param  MicroSeconds  The minimum number of microseconds to delay.
63
64  @return The value of MicroSeconds inputted.
65
66**/
67UINTN
68EFIAPI
69MicroSecondDelay (
70  IN      UINTN                     MicroSeconds
71  )
72{
73  return NanoSecondDelay (MicroSeconds * 1000);
74}
75
76
77/**
78  Stalls the CPU for at least the given number of nanoseconds.
79
80  Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
81
82  @param  NanoSeconds The minimum number of nanoseconds to delay.
83
84  @return The value of NanoSeconds inputted.
85
86**/
87UINTN
88EFIAPI
89NanoSecondDelay (
90  IN      UINTN                     NanoSeconds
91  )
92{
93  EFI_STATUS  Status;
94  UINT64      HundredNanoseconds;
95  UINTN       Index;
96
97  if ((gTimerPeriod != 0) &&
98      ((UINT64)NanoSeconds > gTimerPeriod) &&
99      (EfiGetCurrentTpl () == TPL_APPLICATION)) {
100    //
101    // This stall is long, so use gBS->WaitForEvent () to yield CPU to DXE Core
102    //
103
104    HundredNanoseconds = DivU64x32 (NanoSeconds, 100);
105    Status = gBS->SetTimer (gTimerEvent, TimerRelative, HundredNanoseconds);
106    ASSERT_EFI_ERROR (Status);
107
108    Status = gBS->WaitForEvent (sizeof (gTimerEvent)/sizeof (EFI_EVENT), &gTimerEvent, &Index);
109    ASSERT_EFI_ERROR (Status);
110
111  } else {
112    gEmuThunk->Sleep (NanoSeconds);
113  }
114  return NanoSeconds;
115}
116
117
118/**
119  Retrieves the current value of a 64-bit free running performance counter.
120
121  The counter can either count up by 1 or count down by 1. If the physical
122  performance counter counts by a larger increment, then the counter values
123  must be translated. The properties of the counter can be retrieved from
124  GetPerformanceCounterProperties().
125
126  @return The current value of the free running performance counter.
127
128**/
129UINT64
130EFIAPI
131GetPerformanceCounter (
132  VOID
133  )
134{
135  return gEmuThunk->QueryPerformanceCounter ();
136}
137
138/**
139  Retrieves the 64-bit frequency in Hz and the range of performance counter
140  values.
141
142  If StartValue is not NULL, then the value that the performance counter starts
143  with immediately after is it rolls over is returned in StartValue. If
144  EndValue is not NULL, then the value that the performance counter end with
145  immediately before it rolls over is returned in EndValue. The 64-bit
146  frequency of the performance counter in Hz is always returned. If StartValue
147  is less than EndValue, then the performance counter counts up. If StartValue
148  is greater than EndValue, then the performance counter counts down. For
149  example, a 64-bit free running counter that counts up would have a StartValue
150  of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
151  that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
152
153  @param  StartValue  The value the performance counter starts with when it
154                      rolls over.
155  @param  EndValue    The value that the performance counter ends with before
156                      it rolls over.
157
158  @return The frequency in Hz.
159
160**/
161UINT64
162EFIAPI
163GetPerformanceCounterProperties (
164  OUT      UINT64                    *StartValue,  OPTIONAL
165  OUT      UINT64                    *EndValue     OPTIONAL
166  )
167{
168
169  if (StartValue != NULL) {
170    *StartValue = 0ULL;
171  }
172  if (EndValue != NULL) {
173    *EndValue = (UINT64)-1LL;
174  }
175
176  return gEmuThunk->QueryPerformanceFrequency ();
177}
178
179
180/**
181  Register for the Timer AP protocol.
182
183  @param  ImageHandle   The firmware allocated handle for the EFI image.
184  @param  SystemTable   A pointer to the EFI System Table.
185
186  @retval EFI_SUCCESS   The constructor always returns EFI_SUCCESS.
187
188**/
189EFI_STATUS
190EFIAPI
191DxeTimerLibConstructor (
192  IN EFI_HANDLE        ImageHandle,
193  IN EFI_SYSTEM_TABLE  *SystemTable
194  )
195{
196  EfiCreateProtocolNotifyEvent (
197    &gEfiTimerArchProtocolGuid,
198    TPL_CALLBACK,
199    RegisterTimerArchProtocol,
200    NULL,
201    &gRegistration
202    );
203
204  return EFI_SUCCESS;
205}
206
207