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 array is used in calculating the frequency of local APIC
23 // timer. Refer to IA-32 developers' manual for more details.
25 GLOBAL_REMOVE_IF_UNREFERENCED
26 CONST UINT8 mTimerLibLocalApicDivisor
[] = {
27 0x02, 0x04, 0x08, 0x10,
28 0x02, 0x04, 0x08, 0x10,
29 0x20, 0x40, 0x80, 0x01,
30 0x20, 0x40, 0x80, 0x01
34 Internal function to retrieve the base address of local APIC.
36 Internal function to retrieve the base address of local APIC.
38 @return The base address of local APIC
43 InternalX86GetApicBase (
47 return (UINTN
)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
51 Internal function to return the frequency of the local APIC timer.
53 Internal function to return the frequency of the local APIC timer.
55 @param ApicBase The base address of memory mapped registers of local APIC.
57 @return The frequency of the timer in Hz.
62 InternalX86GetTimerFrequency (
67 PcdGet32(PcdFSBClock
) /
68 mTimerLibLocalApicDivisor
[MmioBitFieldRead32 (ApicBase
+ 0x3e0, 0, 3)];
72 Internal function to read the current tick counter of local APIC.
74 Internal function to read the current tick counter of local APIC.
76 @param ApicBase The base address of memory mapped registers of local APIC.
78 @return The tick counter read.
83 InternalX86GetTimerTick (
87 return MmioRead32 (ApicBase
+ 0x390);
91 Stalls the CPU for at least the given number of ticks.
93 Stalls the CPU for at least the given number of ticks. It's invoked by
94 MicroSecondDelay() and NanoSecondDelay().
96 @param ApicBase The base address of memory mapped registers of local APIC.
97 @param Delay A period of time to delay in ticks.
110 // The target timer count is calculated here
112 Ticks
= InternalX86GetTimerTick (ApicBase
) - Delay
;
115 // Wait until time out
116 // Delay > 2^31 could not be handled by this function
117 // Timer wrap-arounds are handled correctly by this function
119 while (InternalX86GetTimerTick (ApicBase
) - Ticks
>= 0);
123 Stalls the CPU for at least the given number of microseconds.
125 Stalls the CPU for the number of microseconds specified by MicroSeconds.
127 @param MicroSeconds The minimum number of microseconds to delay.
135 IN UINTN MicroSeconds
140 ApicBase
= InternalX86GetApicBase ();
145 InternalX86GetTimerFrequency (ApicBase
),
155 Stalls the CPU for at least the given number of nanoseconds.
157 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
159 @param NanoSeconds The minimum number of nanoseconds to delay.
172 ApicBase
= InternalX86GetApicBase ();
177 InternalX86GetTimerFrequency (ApicBase
),
187 Retrieves the current value of a 64-bit free running performance counter.
189 Retrieves the current value of a 64-bit free running performance counter. The
190 counter can either count up by 1 or count down by 1. If the physical
191 performance counter counts by a larger increment, then the counter values
192 must be translated. The properties of the counter can be retrieved from
193 GetPerformanceCounterProperties().
195 @return The current value of the free running performance counter.
200 GetPerformanceCounter (
204 return (UINT64
)(UINT32
)InternalX86GetTimerTick (InternalX86GetApicBase ());
208 Retrieves the 64-bit frequency in Hz and the range of performance counter
211 If StartValue is not NULL, then the value that the performance counter starts
212 with immediately after is it rolls over is returned in StartValue. If
213 EndValue is not NULL, then the value that the performance counter end with
214 immediately before it rolls over is returned in EndValue. The 64-bit
215 frequency of the performance counter in Hz is always returned. If StartValue
216 is less than EndValue, then the performance counter counts up. If StartValue
217 is greater than EndValue, then the performance counter counts down. For
218 example, a 64-bit free running counter that counts up would have a StartValue
219 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
220 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
222 @param StartValue The value the performance counter starts with when it
224 @param EndValue The value that the performance counter ends with before
227 @return The frequency in Hz.
232 GetPerformanceCounterProperties (
233 OUT UINT64
*StartValue
, OPTIONAL
234 OUT UINT64
*EndValue OPTIONAL
239 ApicBase
= InternalX86GetApicBase ();
241 if (StartValue
!= NULL
) {
242 *StartValue
= MmioRead32 (ApicBase
+ 0x380);
245 if (EndValue
!= NULL
) {
249 return (UINT64
) InternalX86GetTimerFrequency (ApicBase
);;