hwtimer.c revision 281075 
1/******************************************************************************
2 *
3 * Name: hwtimer.c - ACPI Power Management Timer Interface
4 *
5 *****************************************************************************/
6
7/*
8 * Copyright (C) 2000 - 2015, 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 <contrib/dev/acpica/include/acpi.h>
47#include <contrib/dev/acpica/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
66ACPI_STATUS
67AcpiGetTimerResolution (
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
90ACPI_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
105ACPI_STATUS
106AcpiGetTimer (
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
131ACPI_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
163ACPI_STATUS
164AcpiGetTimerDuration (
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
231ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
232
233#endif /* !ACPI_REDUCED_HARDWARE */
234