1 /******************************************************************************
2 *
3 * Name: hwtimer.c - ACPI Power Management Timer Interface
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2013, Intel Corp.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions, and the following disclaimer,
16 * without modification.
17 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
18 * substantially similar to the "NO WARRANTY" disclaimer below
19 * ("Disclaimer") and any redistribution must be conditioned upon
20 * including a substantially similar Disclaimer requirement for further
21 * binary redistribution.
22 * 3. Neither the names of the above-listed copyright holders nor the names
23 * of any contributors may be used to endorse or promote products derived
24 * from this software without specific prior written permission.
25 *
26 * Alternatively, this software may be distributed under the terms of the
27 * GNU General Public License ("GPL") version 2 as published by the Free
28 * Software Foundation.
29 *
30 * NO WARRANTY
31 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
32 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
33 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
34 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
35 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
36 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
37 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
38 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
40 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
41 * POSSIBILITY OF SUCH DAMAGES.
42 */
43
44 #define EXPORT_ACPI_INTERFACES
45
46 #include "acpi.h"
47 #include "accommon.h"
48
49 #define _COMPONENT ACPI_HARDWARE
50 ACPI_MODULE_NAME ("hwtimer")
51
52
53 #if (!ACPI_REDUCED_HARDWARE) /* Entire module */
54 /******************************************************************************
55 *
56 * FUNCTION: AcpiGetTimerResolution
57 *
58 * PARAMETERS: Resolution - Where the resolution is returned
59 *
60 * RETURN: Status and timer resolution
61 *
62 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
63 *
64 ******************************************************************************/
65
66 ACPI_STATUS
67 AcpiGetTimerResolution (
68 UINT32 *Resolution)
69 {
70 ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
71
72
73 if (!Resolution)
74 {
75 return_ACPI_STATUS (AE_BAD_PARAMETER);
76 }
77
78 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
79 {
80 *Resolution = 24;
81 }
82 else
83 {
84 *Resolution = 32;
85 }
86
87 return_ACPI_STATUS (AE_OK);
88 }
89
90 ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
91
92
93 /******************************************************************************
94 *
95 * FUNCTION: AcpiGetTimer
96 *
97 * PARAMETERS: Ticks - Where the timer value is returned
98 *
99 * RETURN: Status and current timer value (ticks)
100 *
101 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
102 *
103 ******************************************************************************/
104
105 ACPI_STATUS
106 AcpiGetTimer (
107 UINT32 *Ticks)
108 {
109 ACPI_STATUS Status;
110
111
112 ACPI_FUNCTION_TRACE (AcpiGetTimer);
113
114
115 if (!Ticks)
116 {
117 return_ACPI_STATUS (AE_BAD_PARAMETER);
118 }
119
120 /* ACPI 5.0A: PM Timer is optional */
121
122 if (!AcpiGbl_FADT.XPmTimerBlock.Address)
123 {
124 return_ACPI_STATUS (AE_SUPPORT);
125 }
126
127 Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
128 return_ACPI_STATUS (Status);
129 }
130
131 ACPI_EXPORT_SYMBOL (AcpiGetTimer)
132
133
134 /******************************************************************************
135 *
136 * FUNCTION: AcpiGetTimerDuration
137 *
138 * PARAMETERS: StartTicks - Starting timestamp
139 * EndTicks - End timestamp
140 * TimeElapsed - Where the elapsed time is returned
141 *
142 * RETURN: Status and TimeElapsed
143 *
144 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
145 * PM Timer time stamps, taking into account the possibility of
146 * rollovers, the timer resolution, and timer frequency.
147 *
148 * The PM Timer's clock ticks at roughly 3.6 times per
149 * _microsecond_, and its clock continues through Cx state
150 * transitions (unlike many CPU timestamp counters) -- making it
151 * a versatile and accurate timer.
152 *
153 * Note that this function accommodates only a single timer
154 * rollover. Thus for 24-bit timers, this function should only
155 * be used for calculating durations less than ~4.6 seconds
156 * (~20 minutes for 32-bit timers) -- calculations below:
157 *
158 * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
159 * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
160 *
161 ******************************************************************************/
162
163 ACPI_STATUS
164 AcpiGetTimerDuration (
165 UINT32 StartTicks,
166 UINT32 EndTicks,
167 UINT32 *TimeElapsed)
168 {
169 ACPI_STATUS Status;
170 UINT32 DeltaTicks;
171 UINT64 Quotient;
172
173
174 ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
175
176
177 if (!TimeElapsed)
178 {
179 return_ACPI_STATUS (AE_BAD_PARAMETER);
180 }
181
182 /* ACPI 5.0A: PM Timer is optional */
183
184 if (!AcpiGbl_FADT.XPmTimerBlock.Address)
185 {
186 return_ACPI_STATUS (AE_SUPPORT);
187 }
188
189 /*
190 * Compute Tick Delta:
191 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
192 */
193 if (StartTicks < EndTicks)
194 {
195 DeltaTicks = EndTicks - StartTicks;
196 }
197 else if (StartTicks > EndTicks)
198 {
199 if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
200 {
201 /* 24-bit Timer */
202
203 DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
204 }
205 else
206 {
207 /* 32-bit Timer */
208
209 DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
210 }
211 }
212 else /* StartTicks == EndTicks */
213 {
214 *TimeElapsed = 0;
215 return_ACPI_STATUS (AE_OK);
216 }
217
218 /*
219 * Compute Duration (Requires a 64-bit multiply and divide):
220 *
221 * TimeElapsed (microseconds) =
222 * (DeltaTicks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
223 */
224 Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * ACPI_USEC_PER_SEC,
225 ACPI_PM_TIMER_FREQUENCY, &Quotient, NULL);
226
227 *TimeElapsed = (UINT32) Quotient;
228 return_ACPI_STATUS (Status);
229 }
230
231 ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
232
233 #endif /* !ACPI_REDUCED_HARDWARE */