hwtimer.c revision 231844 
1
2/******************************************************************************
3 *
4 * Name: hwtimer.c - ACPI Power Management Timer Interface
5 *
6 *****************************************************************************/
7
8/*
9 * Copyright (C) 2000 - 2012, Intel Corp.
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 *    notice, this list of conditions, and the following disclaimer,
17 *    without modification.
18 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
19 *    substantially similar to the "NO WARRANTY" disclaimer below
20 *    ("Disclaimer") and any redistribution must be conditioned upon
21 *    including a substantially similar Disclaimer requirement for further
22 *    binary redistribution.
23 * 3. Neither the names of the above-listed copyright holders nor the names
24 *    of any contributors may be used to endorse or promote products derived
25 *    from this software without specific prior written permission.
26 *
27 * Alternatively, this software may be distributed under the terms of the
28 * GNU General Public License ("GPL") version 2 as published by the Free
29 * Software Foundation.
30 *
31 * NO WARRANTY
32 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
33 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
34 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
35 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
36 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
41 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
42 * POSSIBILITY OF SUCH DAMAGES.
43 */
44
45#include <contrib/dev/acpica/include/acpi.h>
46#include <contrib/dev/acpica/include/accommon.h>
47
48#define _COMPONENT          ACPI_HARDWARE
49        ACPI_MODULE_NAME    ("hwtimer")
50
51
52#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
53/******************************************************************************
54 *
55 * FUNCTION:    AcpiGetTimerResolution
56 *
57 * PARAMETERS:  Resolution          - Where the resolution is returned
58 *
59 * RETURN:      Status and timer resolution
60 *
61 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
62 *
63 ******************************************************************************/
64
65ACPI_STATUS
66AcpiGetTimerResolution (
67    UINT32                  *Resolution)
68{
69    ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
70
71
72    if (!Resolution)
73    {
74        return_ACPI_STATUS (AE_BAD_PARAMETER);
75    }
76
77    if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
78    {
79        *Resolution = 24;
80    }
81    else
82    {
83        *Resolution = 32;
84    }
85
86    return_ACPI_STATUS (AE_OK);
87}
88
89ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
90
91
92/******************************************************************************
93 *
94 * FUNCTION:    AcpiGetTimer
95 *
96 * PARAMETERS:  Ticks               - Where the timer value is returned
97 *
98 * RETURN:      Status and current timer value (ticks)
99 *
100 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
101 *
102 ******************************************************************************/
103
104ACPI_STATUS
105AcpiGetTimer (
106    UINT32                  *Ticks)
107{
108    ACPI_STATUS             Status;
109
110
111    ACPI_FUNCTION_TRACE (AcpiGetTimer);
112
113
114    if (!Ticks)
115    {
116        return_ACPI_STATUS (AE_BAD_PARAMETER);
117    }
118
119    Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
120
121    return_ACPI_STATUS (Status);
122}
123
124ACPI_EXPORT_SYMBOL (AcpiGetTimer)
125
126
127/******************************************************************************
128 *
129 * FUNCTION:    AcpiGetTimerDuration
130 *
131 * PARAMETERS:  StartTicks          - Starting timestamp
132 *              EndTicks            - End timestamp
133 *              TimeElapsed         - Where the elapsed time is returned
134 *
135 * RETURN:      Status and TimeElapsed
136 *
137 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
138 *              PM Timer time stamps, taking into account the possibility of
139 *              rollovers, the timer resolution, and timer frequency.
140 *
141 *              The PM Timer's clock ticks at roughly 3.6 times per
142 *              _microsecond_, and its clock continues through Cx state
143 *              transitions (unlike many CPU timestamp counters) -- making it
144 *              a versatile and accurate timer.
145 *
146 *              Note that this function accommodates only a single timer
147 *              rollover.  Thus for 24-bit timers, this function should only
148 *              be used for calculating durations less than ~4.6 seconds
149 *              (~20 minutes for 32-bit timers) -- calculations below:
150 *
151 *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
152 *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
153 *
154 ******************************************************************************/
155
156ACPI_STATUS
157AcpiGetTimerDuration (
158    UINT32                  StartTicks,
159    UINT32                  EndTicks,
160    UINT32                  *TimeElapsed)
161{
162    ACPI_STATUS             Status;
163    UINT32                  DeltaTicks;
164    UINT64                  Quotient;
165
166
167    ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
168
169
170    if (!TimeElapsed)
171    {
172        return_ACPI_STATUS (AE_BAD_PARAMETER);
173    }
174
175    /*
176     * Compute Tick Delta:
177     * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
178     */
179    if (StartTicks < EndTicks)
180    {
181        DeltaTicks = EndTicks - StartTicks;
182    }
183    else if (StartTicks > EndTicks)
184    {
185        if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
186        {
187            /* 24-bit Timer */
188
189            DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
190        }
191        else
192        {
193            /* 32-bit Timer */
194
195            DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
196        }
197    }
198    else /* StartTicks == EndTicks */
199    {
200        *TimeElapsed = 0;
201        return_ACPI_STATUS (AE_OK);
202    }
203
204    /*
205     * Compute Duration (Requires a 64-bit multiply and divide):
206     *
207     * TimeElapsed = (DeltaTicks * 1000000) / PM_TIMER_FREQUENCY;
208     */
209    Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * 1000000,
210                PM_TIMER_FREQUENCY, &Quotient, NULL);
211
212    *TimeElapsed = (UINT32) Quotient;
213    return_ACPI_STATUS (Status);
214}
215
216ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
217
218#endif /* !ACPI_REDUCED_HARDWARE */
219