updated the comment according to latest version of MWG.
[mirror_edk2.git] / MdePkg / Library / SecPeiDxeTimerLibCpu / x86TimerLib.c
1 /** @file
2 Timer Library functions built upon local APIC on IA32/x64.
3
4 Copyright (c) 2006 - 2007, Intel Corporation<BR>
5 All rights reserved. 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 Module Name: x86TimerLib.c
14
15 **/
16
17 //
18 // The following array is used in calculating the frequency of local APIC
19 // timer. Refer to IA-32 developers' manual for more details.
20 //
21 GLOBAL_REMOVE_IF_UNREFERENCED
22 CONST UINT8 mTimerLibLocalApicDivisor[] = {
23 0x02, 0x04, 0x08, 0x10,
24 0x02, 0x04, 0x08, 0x10,
25 0x20, 0x40, 0x80, 0x01,
26 0x20, 0x40, 0x80, 0x01
27 };
28
29 /**
30 Internal function to retrieve the base address of local APIC.
31
32 Internal function to retrieve the base address of local APIC.
33
34 @return The base address of local APIC
35
36 **/
37 STATIC
38 UINTN
39 InternalX86GetApicBase (
40 VOID
41 )
42 {
43 return (UINTN)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
44 }
45
46 /**
47 Internal function to return the frequency of the local APIC timer.
48
49 Internal function to return the frequency of the local APIC timer.
50
51 @param ApicBase The base address of memory mapped registers of local APIC.
52
53 @return The frequency of the timer in Hz.
54
55 **/
56 STATIC
57 UINT32
58 InternalX86GetTimerFrequency (
59 IN UINTN ApicBase
60 )
61 {
62 return
63 PcdGet32(PcdFSBClock) /
64 mTimerLibLocalApicDivisor[MmioBitFieldRead32 (ApicBase + 0x3e0, 0, 3)];
65 }
66
67 /**
68 Internal function to read the current tick counter of local APIC.
69
70 Internal function to read the current tick counter of local APIC.
71
72 @param ApicBase The base address of memory mapped registers of local APIC.
73
74 @return The tick counter read.
75
76 **/
77 STATIC
78 INT32
79 InternalX86GetTimerTick (
80 IN UINTN ApicBase
81 )
82 {
83 return MmioRead32 (ApicBase + 0x390);
84 }
85
86 /**
87 Stalls the CPU for at least the given number of ticks.
88
89 Stalls the CPU for at least the given number of ticks. It's invoked by
90 MicroSecondDelay() and NanoSecondDelay().
91
92 @param ApicBase The base address of memory mapped registers of local APIC.
93 @param Delay A period of time to delay in ticks.
94
95 **/
96 STATIC
97 VOID
98 InternalX86Delay (
99 IN UINTN ApicBase,
100 IN UINT32 Delay
101 )
102 {
103 INT32 Ticks;
104
105 //
106 // The target timer count is calculated here
107 //
108 Ticks = InternalX86GetTimerTick (ApicBase) - Delay;
109
110 //
111 // Wait until time out
112 // Delay > 2^31 could not be handled by this function
113 // Timer wrap-arounds are handled correctly by this function
114 //
115 while (InternalX86GetTimerTick (ApicBase) - Ticks >= 0);
116 }
117
118 /**
119 Stalls the CPU for at least the given number of microseconds.
120
121 Stalls the CPU for the number of microseconds specified by MicroSeconds.
122
123 @param MicroSeconds The minimum number of microseconds to delay.
124
125 @return MicroSeconds
126
127 **/
128 UINTN
129 EFIAPI
130 MicroSecondDelay (
131 IN UINTN MicroSeconds
132 )
133 {
134 UINTN ApicBase;
135
136 ApicBase = InternalX86GetApicBase ();
137 InternalX86Delay (
138 ApicBase,
139 (UINT32)DivU64x32 (
140 MultU64x64 (
141 InternalX86GetTimerFrequency (ApicBase),
142 MicroSeconds
143 ),
144 1000000u
145 )
146 );
147 return MicroSeconds;
148 }
149
150 /**
151 Stalls the CPU for at least the given number of nanoseconds.
152
153 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
154
155 @param NanoSeconds The minimum number of nanoseconds to delay.
156
157 @return NanoSeconds
158
159 **/
160 UINTN
161 EFIAPI
162 NanoSecondDelay (
163 IN UINTN NanoSeconds
164 )
165 {
166 UINTN ApicBase;
167
168 ApicBase = InternalX86GetApicBase ();
169 InternalX86Delay (
170 ApicBase,
171 (UINT32)DivU64x32 (
172 MultU64x64 (
173 InternalX86GetTimerFrequency (ApicBase),
174 NanoSeconds
175 ),
176 1000000000u
177 )
178 );
179 return NanoSeconds;
180 }
181
182 /**
183 Retrieves the current value of a 64-bit free running performance counter.
184
185 Retrieves the current value of a 64-bit free running performance counter. The
186 counter can either count up by 1 or count down by 1. If the physical
187 performance counter counts by a larger increment, then the counter values
188 must be translated. The properties of the counter can be retrieved from
189 GetPerformanceCounterProperties().
190
191 @return The current value of the free running performance counter.
192
193 **/
194 UINT64
195 EFIAPI
196 GetPerformanceCounter (
197 VOID
198 )
199 {
200 return (UINT64)(UINT32)InternalX86GetTimerTick (InternalX86GetApicBase ());
201 }
202
203 /**
204 Retrieves the 64-bit frequency in Hz and the range of performance counter
205 values.
206
207 If StartValue is not NULL, then the value that the performance counter starts
208 with immediately after is it rolls over is returned in StartValue. If
209 EndValue is not NULL, then the value that the performance counter end with
210 immediately before it rolls over is returned in EndValue. The 64-bit
211 frequency of the performance counter in Hz is always returned. If StartValue
212 is less than EndValue, then the performance counter counts up. If StartValue
213 is greater than EndValue, then the performance counter counts down. For
214 example, a 64-bit free running counter that counts up would have a StartValue
215 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
216 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
217
218 @param StartValue The value the performance counter starts with when it
219 rolls over.
220 @param EndValue The value that the performance counter ends with before
221 it rolls over.
222
223 @return The frequency in Hz.
224
225 **/
226 UINT64
227 EFIAPI
228 GetPerformanceCounterProperties (
229 OUT UINT64 *StartValue, OPTIONAL
230 OUT UINT64 *EndValue OPTIONAL
231 )
232 {
233 UINTN ApicBase;
234
235 ApicBase = InternalX86GetApicBase ();
236
237 if (StartValue != NULL) {
238 *StartValue = MmioRead32 (ApicBase + 0x380);
239 }
240
241 if (EndValue != NULL) {
242 *EndValue = 0;
243 }
244
245 return (UINT64) InternalX86GetTimerFrequency (ApicBase);;
246 }