2 Timer Library functions built upon local APIC on IA32/x64.
4 Copyright (c) 2006 - 2008, 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
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.
16 #include <Library/TimerLib.h>
17 #include <Library/BaseLib.h>
18 #include <Library/IoLib.h>
19 #include <Library/DebugLib.h>
20 #include <Library/PcdLib.h>
24 // The following array is used in calculating the frequency of local APIC
25 // timer. Refer to IA-32 developers' manual for more details.
27 GLOBAL_REMOVE_IF_UNREFERENCED
28 CONST UINT8 mTimerLibLocalApicDivisor
[] = {
29 0x02, 0x04, 0x08, 0x10,
30 0x02, 0x04, 0x08, 0x10,
31 0x20, 0x40, 0x80, 0x01,
32 0x20, 0x40, 0x80, 0x01
36 Internal function to retrieve the base address of local APIC.
38 Internal function to retrieve the base address of local APIC.
40 @return The base address of local APIC
44 InternalX86GetApicBase (
48 return (UINTN
)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
52 Internal function to return the frequency of the local APIC timer.
54 Internal function to return the frequency of the local APIC timer.
56 @param ApicBase The base address of memory mapped registers of local APIC.
58 @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.
82 InternalX86GetTimerTick (
86 return MmioRead32 (ApicBase
+ 0x390);
90 Stalls the CPU for at least the given number of ticks.
92 Stalls the CPU for at least the given number of ticks. It's invoked by
93 MicroSecondDelay() and NanoSecondDelay().
95 @param ApicBase The base address of memory mapped registers of local APIC.
96 @param Delay A period of time to delay in ticks.
108 // The target timer count is calculated here
110 Ticks
= InternalX86GetTimerTick (ApicBase
) - Delay
;
113 // Wait until time out
114 // Delay > 2^31 could not be handled by this function
115 // Timer wrap-arounds are handled correctly by this function
117 while (InternalX86GetTimerTick (ApicBase
) - Ticks
>= 0);
121 Stalls the CPU for at least the given number of microseconds.
123 Stalls the CPU for the number of microseconds specified by MicroSeconds.
125 @param MicroSeconds The minimum number of microseconds to delay.
133 IN UINTN MicroSeconds
138 ApicBase
= InternalX86GetApicBase ();
143 InternalX86GetTimerFrequency (ApicBase
),
153 Stalls the CPU for at least the given number of nanoseconds.
155 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
157 @param NanoSeconds The minimum number of nanoseconds to delay.
170 ApicBase
= InternalX86GetApicBase ();
175 InternalX86GetTimerFrequency (ApicBase
),
185 Retrieves the current value of a 64-bit free running performance counter.
187 Retrieves the current value of a 64-bit free running performance counter. The
188 counter can either count up by 1 or count down by 1. If the physical
189 performance counter counts by a larger increment, then the counter values
190 must be translated. The properties of the counter can be retrieved from
191 GetPerformanceCounterProperties().
193 @return The current value of the free running performance counter.
198 GetPerformanceCounter (
202 return (UINT64
)(UINT32
)InternalX86GetTimerTick (InternalX86GetApicBase ());
206 Retrieves the 64-bit frequency in Hz and the range of performance counter
209 If StartValue is not NULL, then the value that the performance counter starts
210 with immediately after is it rolls over is returned in StartValue. If
211 EndValue is not NULL, then the value that the performance counter end with
212 immediately before it rolls over is returned in EndValue. The 64-bit
213 frequency of the performance counter in Hz is always returned. If StartValue
214 is less than EndValue, then the performance counter counts up. If StartValue
215 is greater than EndValue, then the performance counter counts down. For
216 example, a 64-bit free running counter that counts up would have a StartValue
217 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
218 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
220 @param StartValue The value the performance counter starts with when it
222 @param EndValue The value that the performance counter ends with before
225 @return The frequency in Hz.
230 GetPerformanceCounterProperties (
231 OUT UINT64
*StartValue
, OPTIONAL
232 OUT UINT64
*EndValue OPTIONAL
237 ApicBase
= InternalX86GetApicBase ();
239 if (StartValue
!= NULL
) {
240 *StartValue
= MmioRead32 (ApicBase
+ 0x380);
243 if (EndValue
!= NULL
) {
247 return (UINT64
) InternalX86GetTimerFrequency (ApicBase
);;