2 Timer Library functions built upon local APIC on IA32/x64.
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
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
45 InternalX86GetApicBase (
49 return (UINTN
)AsmMsrBitFieldRead64 (27, 12, 35) << 12;
53 Internal function to return the frequency of the local APIC timer.
55 Internal function to return the frequency of the local APIC timer.
57 @param ApicBase The base address of memory mapped registers of local APIC.
59 @return The frequency of the timer in Hz.
64 InternalX86GetTimerFrequency (
69 PcdGet32(PcdFSBClock
) /
70 mTimerLibLocalApicDivisor
[MmioBitFieldRead32 (ApicBase
+ 0x3e0, 0, 3)];
74 Internal function to read the current tick counter of local APIC.
76 Internal function to read the current tick counter of local APIC.
78 @param ApicBase The base address of memory mapped registers of local APIC.
80 @return The tick counter read.
85 InternalX86GetTimerTick (
89 return MmioRead32 (ApicBase
+ 0x390);
93 Stalls the CPU for at least the given number of ticks.
95 Stalls the CPU for at least the given number of ticks. It's invoked by
96 MicroSecondDelay() and NanoSecondDelay().
98 @param ApicBase The base address of memory mapped registers of local APIC.
99 @param Delay A period of time to delay in ticks.
112 // The target timer count is calculated here
114 Ticks
= InternalX86GetTimerTick (ApicBase
) - Delay
;
117 // Wait until time out
118 // Delay > 2^31 could not be handled by this function
119 // Timer wrap-arounds are handled correctly by this function
121 while (InternalX86GetTimerTick (ApicBase
) - Ticks
>= 0);
125 Stalls the CPU for at least the given number of microseconds.
127 Stalls the CPU for the number of microseconds specified by MicroSeconds.
129 @param MicroSeconds The minimum number of microseconds to delay.
137 IN UINTN MicroSeconds
142 ApicBase
= InternalX86GetApicBase ();
147 InternalX86GetTimerFrequency (ApicBase
),
157 Stalls the CPU for at least the given number of nanoseconds.
159 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
161 @param NanoSeconds The minimum number of nanoseconds to delay.
174 ApicBase
= InternalX86GetApicBase ();
179 InternalX86GetTimerFrequency (ApicBase
),
189 Retrieves the current value of a 64-bit free running performance counter.
191 Retrieves the current value of a 64-bit free running performance counter. The
192 counter can either count up by 1 or count down by 1. If the physical
193 performance counter counts by a larger increment, then the counter values
194 must be translated. The properties of the counter can be retrieved from
195 GetPerformanceCounterProperties().
197 @return The current value of the free running performance counter.
202 GetPerformanceCounter (
206 return (UINT64
)(UINT32
)InternalX86GetTimerTick (InternalX86GetApicBase ());
210 Retrieves the 64-bit frequency in Hz and the range of performance counter
213 If StartValue is not NULL, then the value that the performance counter starts
214 with immediately after is it rolls over is returned in StartValue. If
215 EndValue is not NULL, then the value that the performance counter end with
216 immediately before it rolls over is returned in EndValue. The 64-bit
217 frequency of the performance counter in Hz is always returned. If StartValue
218 is less than EndValue, then the performance counter counts up. If StartValue
219 is greater than EndValue, then the performance counter counts down. For
220 example, a 64-bit free running counter that counts up would have a StartValue
221 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
222 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
224 @param StartValue The value the performance counter starts with when it
226 @param EndValue The value that the performance counter ends with before
229 @return The frequency in Hz.
234 GetPerformanceCounterProperties (
235 OUT UINT64
*StartValue
, OPTIONAL
236 OUT UINT64
*EndValue OPTIONAL
241 ApicBase
= InternalX86GetApicBase ();
243 if (StartValue
!= NULL
) {
244 *StartValue
= MmioRead32 (ApicBase
+ 0x380);
247 if (EndValue
!= NULL
) {
251 return (UINT64
) InternalX86GetTimerFrequency (ApicBase
);;