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.
118 ApicBase
= InternalX86GetApicBase ();
121 // The target timer count is calculated here
123 Ticks
= InternalX86GetTimerTick (ApicBase
) - Delay
;
126 // Wait until time out
127 // Delay > 2^31 could not be handled by this function
128 // Timer wrap-arounds are handled correctly by this function
130 while (InternalX86GetTimerTick (ApicBase
) - Ticks
>= 0);
134 Stalls the CPU for at least the given number of microseconds.
136 Stalls the CPU for the number of microseconds specified by MicroSeconds.
138 @param MicroSeconds The minimum number of microseconds to delay.
146 IN UINTN MicroSeconds
151 ApicBase
= InternalX86GetApicBase ();
156 InternalX86GetTimerFrequency (ApicBase
),
166 Stalls the CPU for at least the given number of nanoseconds.
168 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
170 @param NanoSeconds The minimum number of nanoseconds to delay.
183 ApicBase
= InternalX86GetApicBase ();
188 InternalX86GetTimerFrequency (ApicBase
),
198 Retrieves the current value of a 64-bit free running performance counter.
200 Retrieves the current value of a 64-bit free running performance counter. The
201 counter can either count up by 1 or count down by 1. If the physical
202 performance counter counts by a larger increment, then the counter values
203 must be translated. The properties of the counter can be retrieved from
204 GetPerformanceCounterProperties().
206 @return The current value of the free running performance counter.
211 GetPerformanceCounter (
215 return InternalX86GetTimerTick (InternalX86GetApicBase ());
219 Retrieves the 64-bit frequency in Hz and the range of performance counter
222 If StartValue is not NULL, then the value that the performance counter starts
223 with immediately after is it rolls over is returned in StartValue. If
224 EndValue is not NULL, then the value that the performance counter end with
225 immediately before it rolls over is returned in EndValue. The 64-bit
226 frequency of the performance counter in Hz is always returned. If StartValue
227 is less than EndValue, then the performance counter counts up. If StartValue
228 is greater than EndValue, then the performance counter counts down. For
229 example, a 64-bit free running counter that counts up would have a StartValue
230 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
231 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
233 @param StartValue The value the performance counter starts with when it
235 @param EndValue The value that the performance counter ends with before
238 @return The frequency in Hz.
243 GetPerformanceCounterProperties (
244 IN UINT64
*StartValue
,
250 ApicBase
= InternalX86GetApicBase ();
252 if (StartValue
!= NULL
) {
253 *StartValue
= MmioRead32 (ApicBase
+ 0x380);
256 if (EndValue
!= NULL
) {
260 return InternalX86GetTimerFrequency (ApicBase
);