2 ACPI Timer implements one instance of Timer Library.
4 Copyright (c) 2013 - 2018, Intel Corporation. All rights reserved.<BR>
5 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/PcdLib.h>
19 #include <Library/PciLib.h>
20 #include <Library/IoLib.h>
21 #include <Library/DebugLib.h>
22 #include <IndustryStandard/Acpi.h>
24 GUID mFrequencyHobGuid
= { 0x3fca54f6, 0xe1a2, 0x4b20, { 0xbe, 0x76, 0x92, 0x6b, 0x4b, 0x48, 0xbf, 0xaa }};
27 Internal function to retrieves the 64-bit frequency in Hz.
29 Internal function to retrieves the 64-bit frequency in Hz.
31 @return The frequency in Hz.
35 InternalGetPerformanceCounterFrequency (
40 The constructor function enables ACPI IO space.
42 If ACPI I/O space not enabled, this function will enable it.
43 It will always return RETURN_SUCCESS.
45 @retval EFI_SUCCESS The constructor always returns RETURN_SUCCESS.
50 AcpiTimerLibConstructor (
61 // ASSERT for the invalid PCD values. They must be configured to the real value.
63 ASSERT (PcdGet16 (PcdAcpiIoPciBarRegisterOffset
) != 0xFFFF);
64 ASSERT (PcdGet16 (PcdAcpiIoPortBaseAddress
) != 0xFFFF);
67 // If the register offset to the BAR for the ACPI I/O Port Base Address is 0x0000, then
68 // no PCI register programming is required to enable access to the the ACPI registers
69 // specified by PcdAcpiIoPortBaseAddress
71 if (PcdGet16 (PcdAcpiIoPciBarRegisterOffset
) == 0x0000) {
72 return RETURN_SUCCESS
;
76 // ASSERT for the invalid PCD values. They must be configured to the real value.
78 ASSERT (PcdGet8 (PcdAcpiIoPciDeviceNumber
) != 0xFF);
79 ASSERT (PcdGet8 (PcdAcpiIoPciFunctionNumber
) != 0xFF);
80 ASSERT (PcdGet16 (PcdAcpiIoPciEnableRegisterOffset
) != 0xFFFF);
83 // Retrieve the PCD values for the PCI configuration space required to program the ACPI I/O Port Base Address
85 Bus
= PcdGet8 (PcdAcpiIoPciBusNumber
);
86 Device
= PcdGet8 (PcdAcpiIoPciDeviceNumber
);
87 Function
= PcdGet8 (PcdAcpiIoPciFunctionNumber
);
88 EnableRegister
= PcdGet16 (PcdAcpiIoPciEnableRegisterOffset
);
89 EnableMask
= PcdGet8 (PcdAcpiIoBarEnableMask
);
92 // If ACPI I/O space is not enabled yet, program ACPI I/O base address and enable it.
94 if ((PciRead8 (PCI_LIB_ADDRESS (Bus
, Device
, Function
, EnableRegister
)) & EnableMask
) != EnableMask
) {
96 PCI_LIB_ADDRESS (Bus
, Device
, Function
, PcdGet16 (PcdAcpiIoPciBarRegisterOffset
)),
97 PcdGet16 (PcdAcpiIoPortBaseAddress
)
100 PCI_LIB_ADDRESS (Bus
, Device
, Function
, EnableRegister
),
105 return RETURN_SUCCESS
;
109 Internal function to retrieve the ACPI I/O Port Base Address.
111 Internal function to retrieve the ACPI I/O Port Base Address.
113 @return The 16-bit ACPI I/O Port Base Address.
117 InternalAcpiGetAcpiTimerIoPort (
123 Port
= PcdGet16 (PcdAcpiIoPortBaseAddress
);
126 // If the register offset to the BAR for the ACPI I/O Port Base Address is not 0x0000, then
127 // read the PCI register for the ACPI BAR value in case the BAR has been programmed to a
128 // value other than PcdAcpiIoPortBaseAddress
130 if (PcdGet16 (PcdAcpiIoPciBarRegisterOffset
) != 0x0000) {
131 Port
= PciRead16 (PCI_LIB_ADDRESS (
132 PcdGet8 (PcdAcpiIoPciBusNumber
),
133 PcdGet8 (PcdAcpiIoPciDeviceNumber
),
134 PcdGet8 (PcdAcpiIoPciFunctionNumber
),
135 PcdGet16 (PcdAcpiIoPciBarRegisterOffset
)
139 return (Port
& PcdGet16 (PcdAcpiIoPortBaseAddressMask
)) + PcdGet16 (PcdAcpiPm1TmrOffset
);
143 Stalls the CPU for at least the given number of ticks.
145 Stalls the CPU for at least the given number of ticks. It's invoked by
146 MicroSecondDelay() and NanoSecondDelay().
148 @param Delay A period of time to delay in ticks.
160 Port
= InternalAcpiGetAcpiTimerIoPort ();
165 // The target timer count is calculated here
167 Ticks
= IoBitFieldRead32 (Port
, 0, 23) + Delay
;
170 // Wait until time out
171 // Delay >= 2^23 could not be handled by this function
172 // Timer wrap-arounds are handled correctly by this function
174 while (((Ticks
- IoBitFieldRead32 (Port
, 0, 23)) & BIT23
) == 0) {
177 } while (Times
-- > 0);
181 Stalls the CPU for at least the given number of microseconds.
183 Stalls the CPU for the number of microseconds specified by MicroSeconds.
185 @param MicroSeconds The minimum number of microseconds to delay.
193 IN UINTN MicroSeconds
209 Stalls the CPU for at least the given number of nanoseconds.
211 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
213 @param NanoSeconds The minimum number of nanoseconds to delay.
237 Retrieves the current value of a 64-bit free running performance counter.
239 Retrieves the current value of a 64-bit free running performance counter. The
240 counter can either count up by 1 or count down by 1. If the physical
241 performance counter counts by a larger increment, then the counter values
242 must be translated. The properties of the counter can be retrieved from
243 GetPerformanceCounterProperties().
245 @return The current value of the free running performance counter.
250 GetPerformanceCounter (
254 return AsmReadTsc ();
258 Retrieves the 64-bit frequency in Hz and the range of performance counter
261 If StartValue is not NULL, then the value that the performance counter starts
262 with immediately after is it rolls over is returned in StartValue. If
263 EndValue is not NULL, then the value that the performance counter end with
264 immediately before it rolls over is returned in EndValue. The 64-bit
265 frequency of the performance counter in Hz is always returned. If StartValue
266 is less than EndValue, then the performance counter counts up. If StartValue
267 is greater than EndValue, then the performance counter counts down. For
268 example, a 64-bit free running counter that counts up would have a StartValue
269 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
270 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
272 @param StartValue The value the performance counter starts with when it
274 @param EndValue The value that the performance counter ends with before
277 @return The frequency in Hz.
282 GetPerformanceCounterProperties (
283 OUT UINT64
*StartValue
, OPTIONAL
284 OUT UINT64
*EndValue OPTIONAL
287 if (StartValue
!= NULL
) {
291 if (EndValue
!= NULL
) {
292 *EndValue
= 0xffffffffffffffffULL
;
294 return InternalGetPerformanceCounterFrequency ();
298 Converts elapsed ticks of performance counter to time in nanoseconds.
300 This function converts the elapsed ticks of running performance counter to
301 time value in unit of nanoseconds.
303 @param Ticks The number of elapsed ticks of running performance counter.
305 @return The elapsed time in nanoseconds.
310 GetTimeInNanoSecond (
319 Frequency
= GetPerformanceCounterProperties (NULL
, NULL
);
323 // Time = --------- x 1,000,000,000
326 NanoSeconds
= MultU64x32 (DivU64x64Remainder (Ticks
, Frequency
, &Remainder
), 1000000000u);
329 // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
330 // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
331 // i.e. highest bit set in Remainder should <= 33.
333 Shift
= MAX (0, HighBitSet64 (Remainder
) - 33);
334 Remainder
= RShiftU64 (Remainder
, (UINTN
) Shift
);
335 Frequency
= RShiftU64 (Frequency
, (UINTN
) Shift
);
336 NanoSeconds
+= DivU64x64Remainder (MultU64x32 (Remainder
, 1000000000u), Frequency
, NULL
);
342 Calculate TSC frequency.
344 The TSC counting frequency is determined by comparing how far it counts
345 during a 101.4 us period as determined by the ACPI timer.
346 The ACPI timer is used because it counts at a known frequency.
347 The TSC is sampled, followed by waiting 363 counts of the ACPI timer,
348 or 101.4 us. The TSC is then sampled again. The difference multiplied by
349 9861 is the TSC frequency. There will be a small error because of the
350 overhead of reading the ACPI timer. An attempt is made to determine and
351 compensate for this error.
353 @return The number of TSC counts per second.
357 InternalCalculateTscFrequency (
366 BOOLEAN InterruptState
;
368 InterruptState
= SaveAndDisableInterrupts ();
370 TimerAddr
= InternalAcpiGetAcpiTimerIoPort ();
372 // Compute the number of ticks to wait to measure TSC frequency.
373 // Use 363 * 9861 = 3579543 Hz which is within 2 Hz of ACPI_TIMER_FREQUENCY.
374 // 363 counts is a calibration time of 101.4 uS.
376 Ticks
= IoBitFieldRead32 (TimerAddr
, 0, 23) + 363;
378 StartTSC
= AsmReadTsc (); // Get base value for the TSC
380 // Wait until the ACPI timer has counted 101.4 us.
381 // Timer wrap-arounds are handled correctly by this function.
382 // When the current ACPI timer value is greater than 'Ticks',
383 // the while loop will exit.
385 while (((Ticks
- IoBitFieldRead32 (TimerAddr
, 0, 23)) & BIT23
) == 0) {
388 EndTSC
= AsmReadTsc (); // TSC value 101.4 us later
390 TscFrequency
= MultU64x32 (
391 (EndTSC
- StartTSC
), // Number of TSC counts in 101.4 us
392 9861 // Number of 101.4 us in a second
395 SetInterruptState (InterruptState
);