1 /** @file
2 CPUID Leaf 0x15 for Core Crystal Clock frequency instance of Timer Library.
3
4 Copyright (c) 2019 Intel Corporation. All rights reserved.<BR>
5 SPDX-License-Identifier: BSD-2-Clause-Patent
6
7 **/
8
9 #include <Base.h>
10 #include <Library/TimerLib.h>
11 #include <Library/BaseLib.h>
12 #include <Library/PcdLib.h>
13 #include <Library/DebugLib.h>
14 #include <Register/Cpuid.h>
15
16 GUID mCpuCrystalFrequencyHobGuid = { 0xe1ec5ad0, 0x8569, 0x46bd, { 0x8d, 0xcd, 0x3b, 0x9f, 0x6f, 0x45, 0x82, 0x7a } };
17
18 /**
19 Internal function to retrieves the 64-bit frequency in Hz.
20
21 Internal function to retrieves the 64-bit frequency in Hz.
22
23 @return The frequency in Hz.
24
25 **/
26 UINT64
27 InternalGetPerformanceCounterFrequency (
28 VOID
29 );
30
31 /**
32 CPUID Leaf 0x15 for Core Crystal Clock Frequency.
33
34 The TSC counting frequency is determined by using CPUID leaf 0x15. Frequency in MHz = Core XTAL frequency * EBX/EAX.
35 In newer flavors of the CPU, core xtal frequency is returned in ECX or 0 if not supported.
36 @return The number of TSC counts per second.
37
38 **/
39 UINT64
CpuidCoreClockCalculateTscFrequency(VOID)40 CpuidCoreClockCalculateTscFrequency (
41 VOID
42 )
43 {
44 UINT64 TscFrequency;
45 UINT64 CoreXtalFrequency;
46 UINT32 RegEax;
47 UINT32 RegEbx;
48 UINT32 RegEcx;
49
50 //
51 // Use CPUID leaf 0x15 Time Stamp Counter and Nominal Core Crystal Clock Information
52 // EBX returns 0 if not supported. ECX, if non zero, provides Core Xtal Frequency in hertz.
53 // TSC frequency = (ECX, Core Xtal Frequency) * EBX/EAX.
54 //
55 AsmCpuid (CPUID_TIME_STAMP_COUNTER, &RegEax, &RegEbx, &RegEcx, NULL);
56
57 //
58 // If EAX or EBX returns 0, the XTAL ratio is not enumerated.
59 //
60 if (RegEax == 0 || RegEbx ==0 ) {
61 ASSERT (RegEax != 0);
62 ASSERT (RegEbx != 0);
63 return 0;
64 }
65 //
66 // If ECX returns 0, the XTAL frequency is not enumerated.
67 // And PcdCpuCoreCrystalClockFrequency defined should base on processor series.
68 //
69 if (RegEcx == 0) {
70 CoreXtalFrequency = PcdGet64 (PcdCpuCoreCrystalClockFrequency);
71 } else {
72 CoreXtalFrequency = (UINT64) RegEcx;
73 }
74
75 //
76 // Calculate TSC frequency = (ECX, Core Xtal Frequency) * EBX/EAX
77 //
78 TscFrequency = DivU64x32 (MultU64x32 (CoreXtalFrequency, RegEbx) + (UINT64)(RegEax >> 1), RegEax);
79
80 return TscFrequency;
81 }
82
83 /**
84 Stalls the CPU for at least the given number of ticks.
85
86 Stalls the CPU for at least the given number of ticks. It's invoked by
87 MicroSecondDelay() and NanoSecondDelay().
88
89 @param Delay A period of time to delay in ticks.
90
91 **/
92 VOID
InternalCpuDelay(IN UINT64 Delay)93 InternalCpuDelay (
94 IN UINT64 Delay
95 )
96 {
97 UINT64 Ticks;
98
99 //
100 // The target timer count is calculated here
101 //
102 Ticks = AsmReadTsc() + Delay;
103
104 //
105 // Wait until time out
106 // Timer wrap-arounds are NOT handled correctly by this function.
107 // Thus, this function must be called within 10 years of reset since
108 // Intel guarantees a minimum of 10 years before the TSC wraps.
109 //
110 while (AsmReadTsc() <= Ticks) {
111 CpuPause();
112 }
113 }
114
115 /**
116 Stalls the CPU for at least the given number of microseconds.
117
118 Stalls the CPU for the number of microseconds specified by MicroSeconds.
119
120 @param[in] MicroSeconds The minimum number of microseconds to delay.
121
122 @return MicroSeconds
123
124 **/
125 UINTN
126 EFIAPI
MicroSecondDelay(IN UINTN MicroSeconds)127 MicroSecondDelay (
128 IN UINTN MicroSeconds
129 )
130 {
131
132 InternalCpuDelay (
133 DivU64x32 (
134 MultU64x64 (
135 MicroSeconds,
136 InternalGetPerformanceCounterFrequency ()
137 ),
138 1000000u
139 )
140 );
141
142 return MicroSeconds;
143 }
144
145 /**
146 Stalls the CPU for at least the given number of nanoseconds.
147
148 Stalls the CPU for the number of nanoseconds specified by NanoSeconds.
149
150 @param NanoSeconds The minimum number of nanoseconds to delay.
151
152 @return NanoSeconds
153
154 **/
155 UINTN
156 EFIAPI
NanoSecondDelay(IN UINTN NanoSeconds)157 NanoSecondDelay (
158 IN UINTN NanoSeconds
159 )
160 {
161
162 InternalCpuDelay (
163 DivU64x32 (
164 MultU64x64 (
165 NanoSeconds,
166 InternalGetPerformanceCounterFrequency ()
167 ),
168 1000000000u
169 )
170 );
171
172 return NanoSeconds;
173 }
174
175 /**
176 Retrieves the current value of a 64-bit free running performance counter.
177
178 Retrieves the current value of a 64-bit free running performance counter. The
179 counter can either count up by 1 or count down by 1. If the physical
180 performance counter counts by a larger increment, then the counter values
181 must be translated. The properties of the counter can be retrieved from
182 GetPerformanceCounterProperties().
183
184 @return The current value of the free running performance counter.
185
186 **/
187 UINT64
188 EFIAPI
GetPerformanceCounter(VOID)189 GetPerformanceCounter (
190 VOID
191 )
192 {
193 return AsmReadTsc ();
194 }
195
196 /**
197 Retrieves the 64-bit frequency in Hz and the range of performance counter
198 values.
199
200 If StartValue is not NULL, then the value that the performance counter starts
201 with immediately after is it rolls over is returned in StartValue. If
202 EndValue is not NULL, then the value that the performance counter end with
203 immediately before it rolls over is returned in EndValue. The 64-bit
204 frequency of the performance counter in Hz is always returned. If StartValue
205 is less than EndValue, then the performance counter counts up. If StartValue
206 is greater than EndValue, then the performance counter counts down. For
207 example, a 64-bit free running counter that counts up would have a StartValue
208 of 0 and an EndValue of 0xFFFFFFFFFFFFFFFF. A 24-bit free running counter
209 that counts down would have a StartValue of 0xFFFFFF and an EndValue of 0.
210
211 @param StartValue The value the performance counter starts with when it
212 rolls over.
213 @param EndValue The value that the performance counter ends with before
214 it rolls over.
215
216 @return The frequency in Hz.
217
218 **/
219 UINT64
220 EFIAPI
GetPerformanceCounterProperties(OUT UINT64 * StartValue,OPTIONAL OUT UINT64 * EndValue OPTIONAL)221 GetPerformanceCounterProperties (
222 OUT UINT64 *StartValue, OPTIONAL
223 OUT UINT64 *EndValue OPTIONAL
224 )
225 {
226 if (StartValue != NULL) {
227 *StartValue = 0;
228 }
229
230 if (EndValue != NULL) {
231 *EndValue = 0xffffffffffffffffULL;
232 }
233 return InternalGetPerformanceCounterFrequency ();
234 }
235
236 /**
237 Converts elapsed ticks of performance counter to time in nanoseconds.
238
239 This function converts the elapsed ticks of running performance counter to
240 time value in unit of nanoseconds.
241
242 @param Ticks The number of elapsed ticks of running performance counter.
243
244 @return The elapsed time in nanoseconds.
245
246 **/
247 UINT64
248 EFIAPI
GetTimeInNanoSecond(IN UINT64 Ticks)249 GetTimeInNanoSecond (
250 IN UINT64 Ticks
251 )
252 {
253 UINT64 Frequency;
254 UINT64 NanoSeconds;
255 UINT64 Remainder;
256 INTN Shift;
257
258 Frequency = GetPerformanceCounterProperties (NULL, NULL);
259
260 //
261 // Ticks
262 // Time = --------- x 1,000,000,000
263 // Frequency
264 //
265 NanoSeconds = MultU64x32 (DivU64x64Remainder (Ticks, Frequency, &Remainder), 1000000000u);
266
267 //
268 // Ensure (Remainder * 1,000,000,000) will not overflow 64-bit.
269 // Since 2^29 < 1,000,000,000 = 0x3B9ACA00 < 2^30, Remainder should < 2^(64-30) = 2^34,
270 // i.e. highest bit set in Remainder should <= 33.
271 //
272 Shift = MAX (0, HighBitSet64 (Remainder) - 33);
273 Remainder = RShiftU64 (Remainder, (UINTN) Shift);
274 Frequency = RShiftU64 (Frequency, (UINTN) Shift);
275 NanoSeconds += DivU64x64Remainder (MultU64x32 (Remainder, 1000000000u), Frequency, NULL);
276
277 return NanoSeconds;
278 }
279
280