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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) 2011-2016, 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)
27 // Select appropriate multiply function for platform architecture.
29 #define MultU64xN MultU64x32
31 #define MultU64xN MultU64x64
42 // Check if the ARM Generic Timer Extension is implemented.
44 if (ArmIsArchTimerImplemented ()) {
47 // Check if Architectural Timer frequency is pre-determined by the platform
50 if (PcdGet32 (PcdArmArchTimerFreqInHz
) != 0) {
52 // Check if ticks/uS is not 0. The Architectural timer runs at constant
53 // frequency, irrespective of CPU frequency. According to Generic Timer
54 // Ref manual, lower bound of the frequency is in the range of 1-10MHz.
56 ASSERT (TICKS_PER_MICRO_SEC
);
60 // Only set the frequency for ARMv7. We expect the secure firmware to
61 // have already done it.
62 // If the security extension is not implemented, set Timer Frequency
65 if ((ArmReadIdPfr1 () & ARM_PFR1_SEC
) == 0x0) {
66 ArmGenericTimerSetTimerFreq (PcdGet32 (PcdArmArchTimerFreqInHz
));
72 // Architectural Timer Frequency must be set in Secure privileged
73 // mode (if secure extension is supported).
74 // If the reset value (0) is returned, just ASSERT.
76 ASSERT (ArmGenericTimerGetTimerFreq () != 0);
79 DEBUG ((EFI_D_ERROR
, "ARM Architectural Timer is not available in the CPU, hence this library cannot be used.\n"));
83 return RETURN_SUCCESS
;
87 A local utility function that returns the PCD value, if specified.
88 Otherwise it defaults to ArmGenericTimerGetTimerFreq.
90 @return The timer frequency.
96 GetPlatformTimerFreq (
101 TimerFreq
= PcdGet32 (PcdArmArchTimerFreqInHz
);
102 if (TimerFreq
== 0) {
103 TimerFreq
= ArmGenericTimerGetTimerFreq ();
110 Stalls the CPU for the number of microseconds specified by MicroSeconds.
112 @param MicroSeconds The minimum number of microseconds to delay.
114 @return The value of MicroSeconds input.
120 IN UINTN MicroSeconds
124 UINT64 SystemCounterVal
;
126 // Calculate counter ticks that represent requested delay:
127 // = MicroSeconds x TICKS_PER_MICRO_SEC
128 // = MicroSeconds x Frequency.10^-6
129 TimerTicks64
= DivU64x32 (
132 GetPlatformTimerFreq ()
137 // Read System Counter value
138 SystemCounterVal
= ArmGenericTimerGetSystemCount ();
140 TimerTicks64
+= SystemCounterVal
;
142 // Wait until delay count expires.
143 while (SystemCounterVal
< TimerTicks64
) {
144 SystemCounterVal
= ArmGenericTimerGetSystemCount ();
152 Stalls the CPU for at least the given number of nanoseconds.
154 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
156 When the timer frequency is 1MHz, each tick corresponds to 1 microsecond.
157 Therefore, the nanosecond delay will be rounded up to the nearest 1 microsecond.
159 @param NanoSeconds The minimum number of nanoseconds to delay.
161 @return The value of NanoSeconds inputed.
172 // Round up to 1us Tick Number
173 MicroSeconds
= NanoSeconds
/ 1000;
174 MicroSeconds
+= ((NanoSeconds
% 1000) == 0) ? 0 : 1;
176 MicroSecondDelay (MicroSeconds
);
182 Retrieves the current value of a 64-bit free running performance counter.
184 The counter can either count up by 1 or count down by 1. If the physical
185 performance counter counts by a larger increment, then the counter values
186 must be translated. The properties of the counter can be retrieved from
187 GetPerformanceCounterProperties().
189 @return The current value of the free running performance counter.
194 GetPerformanceCounter (
198 // Just return the value of system count
199 return ArmGenericTimerGetSystemCount ();
203 Retrieves the 64-bit frequency in Hz and the range of performance counter
206 If StartValue is not NULL, then the value that the performance counter starts
207 with immediately after is it rolls over is returned in StartValue. If
208 EndValue is not NULL, then the value that the performance counter end with
209 immediately before it rolls over is returned in EndValue. The 64-bit
210 frequency of the performance counter in Hz is always returned. If StartValue
211 is less than EndValue, then the performance counter counts up. If StartValue
212 is greater than EndValue, then the performance counter counts down. For
213 example, a 64-bit free running counter that counts up would have a StartValue
214 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
215 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
217 @param StartValue The value the performance counter starts with when it
219 @param EndValue The value that the performance counter ends with before
222 @return The frequency in Hz.
227 GetPerformanceCounterProperties (
228 OUT UINT64
*StartValue
, OPTIONAL
229 OUT UINT64
*EndValue OPTIONAL
232 if (StartValue
!= NULL
) {
234 *StartValue
= (UINT64
)0ULL ;
237 if (EndValue
!= NULL
) {
239 *EndValue
= 0xFFFFFFFFFFFFFFFFUL
;
242 return (UINT64
)ArmGenericTimerGetTimerFreq ();
246 Converts elapsed ticks of performance counter to time in nanoseconds.
248 This function converts the elapsed ticks of running performance counter to
249 time value in unit of nanoseconds.
251 @param Ticks The number of elapsed ticks of running performance counter.
253 @return The elapsed time in nanoseconds.
258 GetTimeInNanoSecond (
266 TimerFreq
= GetPlatformTimerFreq ();
269 // Time = --------- x 1,000,000,000
272 NanoSeconds
= MultU64xN (
281 // Frequency < 0x100000000, so Remainder < 0x100000000, then (Remainder * 1,000,000,000)
282 // will not overflow 64-bit.
284 NanoSeconds
+= DivU64x32 (