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git.proxmox.com Git - mirror_edk2.git/blob - ArmPkg/Library/ArmArchTimerLib/ArmArchTimerLib.c
2 Generic ARM implementation of TimerLib.h
4 Copyright (c) 2011-2014, ARM Limited. All rights reserved.
6 This program and the accompanying materials
7 are licensed and made available under the terms and conditions of the BSD License
8 which accompanies this distribution. The full text of the license may be found at
9 http://opensource.org/licenses/bsd-license.php
11 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
12 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
18 #include <Library/ArmLib.h>
19 #include <Library/BaseLib.h>
20 #include <Library/TimerLib.h>
21 #include <Library/DebugLib.h>
22 #include <Library/PcdLib.h>
23 #include <Library/ArmGenericTimerCounterLib.h>
25 #define TICKS_PER_MICRO_SEC (PcdGet32 (PcdArmArchTimerFreqInHz)/1000000U)
34 // Check if the ARM Generic Timer Extension is implemented.
36 if (ArmIsArchTimerImplemented ()) {
40 // Check if Architectural Timer frequency is pre-determined by the platform
43 if (PcdGet32 (PcdArmArchTimerFreqInHz
) != 0) {
45 // Check if ticks/uS is not 0. The Architectural timer runs at constant
46 // frequency, irrespective of CPU frequency. According to General Timer
47 // Ref manual, lower bound of the frequency is in the range of 1-10MHz.
49 ASSERT (TICKS_PER_MICRO_SEC
);
53 // Only set the frequency for ARMv7. We expect the secure firmware to
54 // have already done it.
55 // If the security extension is not implemented, set Timer Frequency
58 if ((ArmReadIdPfr1 () & ARM_PFR1_SEC
) == 0x0) {
59 ArmGenericTimerSetTimerFreq (PcdGet32 (PcdArmArchTimerFreqInHz
));
65 // Architectural Timer Frequency must be set in the Secure privileged
66 // mode (if secure extension is supported).
67 // If the reset value (0) is returned, just ASSERT.
69 TimerFreq
= ArmGenericTimerGetTimerFreq ();
70 ASSERT (TimerFreq
!= 0);
72 DEBUG ((EFI_D_ERROR
, "ARM Architectural Timer is not available in the CPU, hence this library can not be used.\n"));
76 return RETURN_SUCCESS
;
81 Stalls the CPU for the number of microseconds specified by MicroSeconds.
83 @param MicroSeconds The minimum number of microseconds to delay.
85 @return The value of MicroSeconds inputted.
95 UINT64 SystemCounterVal
;
98 IN UINT64 Multiplicand
,
104 MultU64xN
= MultU64x32
;
106 MultU64xN
= MultU64x64
;
109 TimerFreq
= PcdGet32 (PcdArmArchTimerFreqInHz
);
110 if (TimerFreq
== 0) {
111 TimerFreq
= ArmGenericTimerGetTimerFreq ();
114 // Calculate counter ticks that can represent requested delay:
115 // = MicroSeconds x TICKS_PER_MICRO_SEC
116 // = MicroSeconds x Frequency.10^-6
117 TimerTicks64
= DivU64x32 (
125 // Read System Counter value
126 SystemCounterVal
= ArmGenericTimerGetSystemCount ();
128 TimerTicks64
+= SystemCounterVal
;
130 // Wait until delay count is expired.
131 while (SystemCounterVal
< TimerTicks64
) {
132 SystemCounterVal
= ArmGenericTimerGetSystemCount ();
140 Stalls the CPU for at least the given number of nanoseconds.
142 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
144 When the timer frequency is 1MHz, each tick corresponds to 1 microsecond.
145 Therefore, the nanosecond delay will be rounded up to the nearest 1 microsecond.
147 @param NanoSeconds The minimum number of nanoseconds to delay.
149 @return The value of NanoSeconds inputed.
160 // Round up to 1us Tick Number
161 MicroSeconds
= NanoSeconds
/ 1000;
162 MicroSeconds
+= ((NanoSeconds
% 1000) == 0) ? 0 : 1;
164 MicroSecondDelay (MicroSeconds
);
170 Retrieves the current value of a 64-bit free running performance counter.
172 The counter can either count up by 1 or count down by 1. If the physical
173 performance counter counts by a larger increment, then the counter values
174 must be translated. The properties of the counter can be retrieved from
175 GetPerformanceCounterProperties().
177 @return The current value of the free running performance counter.
182 GetPerformanceCounter (
186 // Just return the value of system count
187 return ArmGenericTimerGetSystemCount ();
191 Retrieves the 64-bit frequency in Hz and the range of performance counter
194 If StartValue is not NULL, then the value that the performance counter starts
195 with immediately after is it rolls over is returned in StartValue. If
196 EndValue is not NULL, then the value that the performance counter end with
197 immediately before it rolls over is returned in EndValue. The 64-bit
198 frequency of the performance counter in Hz is always returned. If StartValue
199 is less than EndValue, then the performance counter counts up. If StartValue
200 is greater than EndValue, then the performance counter counts down. For
201 example, a 64-bit free running counter that counts up would have a StartValue
202 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
203 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
205 @param StartValue The value the performance counter starts with when it
207 @param EndValue The value that the performance counter ends with before
210 @return The frequency in Hz.
215 GetPerformanceCounterProperties (
216 OUT UINT64
*StartValue
, OPTIONAL
217 OUT UINT64
*EndValue OPTIONAL
220 if (StartValue
!= NULL
) {
221 // Timer starts with the reload value
222 *StartValue
= (UINT64
)0ULL ;
225 if (EndValue
!= NULL
) {
226 // Timer counts down to 0x0
227 *EndValue
= 0xFFFFFFFFFFFFFFFFUL
;
230 return (UINT64
)ArmGenericTimerGetTimerFreq ();