2 Timer Library functions built upon local APIC on IA32/x64.
4 @bug Should use PCD to retrieve all the constants including index of
5 the IA32_APIC_BASE MSR, the offsets of InitialCount, CorrentCount
6 and DivideConfiguration.
8 Copyright (c) 2006, Intel Corporation<BR>
9 All rights reserved. This program and the accompanying materials
10 are licensed and made available under the terms and conditions of the BSD License
11 which accompanies this distribution. The full text of the license may be found at
12 http://opensource.org/licenses/bsd-license.php
14 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
15 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
17 Module Name: x86TimerLib.c
22 // The following 2 arrays are used in calculating the frequency of local APIC
23 // timer. Refer to IA-32 developers' manual for more details.
26 GLOBAL_REMOVE_IF_UNREFERENCED
27 CONST UINT32 mTimerLibLocalApicFrequencies
[] = {
34 GLOBAL_REMOVE_IF_UNREFERENCED
35 CONST UINT8 mTimerLibLocalApicDivisor
[] = {
36 0x02, 0x04, 0x08, 0x10,
37 0x02, 0x04, 0x08, 0x10,
38 0x20, 0x40, 0x80, 0x01,
39 0x20, 0x40, 0x80, 0x01
43 Internal function to retrieve the base address of local APIC.
45 Internal function to retrieve the base address of local APIC.
47 @return The base address of local APIC
52 InternalX86GetApicBase (
56 return (UINTN
)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
60 Internal function to return the frequency of the local APIC timer.
62 Internal function to return the frequency of the local APIC timer.
64 @param ApicBase The base address of memory mapped registers of local APIC.
66 @return The frequency of the timer in Hz.
71 InternalX86GetTimerFrequency (
76 mTimerLibLocalApicFrequencies
[AsmMsrBitFieldRead32 (44, 16, 18)] /
77 mTimerLibLocalApicDivisor
[MmioBitFieldRead32 (ApicBase
+ 0x3e0, 0, 3)];
81 Internal function to read the current tick counter of local APIC.
83 Internal function to read the current tick counter of local APIC.
85 @param ApicBase The base address of memory mapped registers of local APIC.
87 @return The tick counter read.
92 InternalX86GetTimerTick (
96 return MmioRead32 (ApicBase
+ 0x390);
100 Stalls the CPU for at least the given number of ticks.
102 Stalls the CPU for at least the given number of ticks. It's invoked by
103 MicroSecondDelay() and NanoSecondDelay().
105 @param ApicBase The base address of memory mapped registers of local APIC.
106 @param Delay A period of time to delay in ticks.
119 // The target timer count is calculated here
121 Ticks
= InternalX86GetTimerTick (ApicBase
) - Delay
;
124 // Wait until time out
125 // Delay > 2^31 could not be handled by this function
126 // Timer wrap-arounds are handled correctly by this function
128 while (InternalX86GetTimerTick (ApicBase
) - Ticks
>= 0);
132 Stalls the CPU for at least the given number of microseconds.
134 Stalls the CPU for the number of microseconds specified by MicroSeconds.
136 @param MicroSeconds The minimum number of microseconds to delay.
144 IN UINTN MicroSeconds
149 ApicBase
= InternalX86GetApicBase ();
154 InternalX86GetTimerFrequency (ApicBase
),
164 Stalls the CPU for at least the given number of nanoseconds.
166 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
168 @param NanoSeconds The minimum number of nanoseconds to delay.
181 ApicBase
= InternalX86GetApicBase ();
186 InternalX86GetTimerFrequency (ApicBase
),
196 Retrieves the current value of a 64-bit free running performance counter.
198 Retrieves the current value of a 64-bit free running performance counter. The
199 counter can either count up by 1 or count down by 1. If the physical
200 performance counter counts by a larger increment, then the counter values
201 must be translated. The properties of the counter can be retrieved from
202 GetPerformanceCounterProperties().
204 @return The current value of the free running performance counter.
209 GetPerformanceCounter (
213 return (UINT64
)(UINT32
)InternalX86GetTimerTick (InternalX86GetApicBase ());
217 Retrieves the 64-bit frequency in Hz and the range of performance counter
220 If StartValue is not NULL, then the value that the performance counter starts
221 with immediately after is it rolls over is returned in StartValue. If
222 EndValue is not NULL, then the value that the performance counter end with
223 immediately before it rolls over is returned in EndValue. The 64-bit
224 frequency of the performance counter in Hz is always returned. If StartValue
225 is less than EndValue, then the performance counter counts up. If StartValue
226 is greater than EndValue, then the performance counter counts down. For
227 example, a 64-bit free running counter that counts up would have a StartValue
228 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
229 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
231 @param StartValue The value the performance counter starts with when it
233 @param EndValue The value that the performance counter ends with before
236 @return The frequency in Hz.
241 GetPerformanceCounterProperties (
242 OUT UINT64
*StartValue
, OPTIONAL
243 OUT UINT64
*EndValue OPTIONAL
248 ApicBase
= InternalX86GetApicBase ();
250 if (StartValue
!= NULL
) {
251 *StartValue
= MmioRead32 (ApicBase
+ 0x380);
254 if (EndValue
!= NULL
) {
258 return (UINT64
)InternalX86GetTimerFrequency (ApicBase
);