1
2/******************************************************************************
3 *
4 * Name: hwtimer.c - ACPI Power Management Timer Interface
5 *
6 *****************************************************************************/
7
8/*
9 * Copyright (C) 2000 - 2011, 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/******************************************************************************
53 *
54 * FUNCTION:    AcpiGetTimerResolution
55 *
56 * PARAMETERS:  Resolution          - Where the resolution is returned
57 *
58 * RETURN:      Status and timer resolution
59 *
60 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
61 *
62 ******************************************************************************/
63
64ACPI_STATUS
65AcpiGetTimerResolution (
66    UINT32                  *Resolution)
67{
68    ACPI_FUNCTION_TRACE (AcpiGetTimerResolution);
69
70
71    if (!Resolution)
72    {
73        return_ACPI_STATUS (AE_BAD_PARAMETER);
74    }
75
76    if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
77    {
78        *Resolution = 24;
79    }
80    else
81    {
82        *Resolution = 32;
83    }
84
85    return_ACPI_STATUS (AE_OK);
86}
87
88ACPI_EXPORT_SYMBOL (AcpiGetTimerResolution)
89
90
91/******************************************************************************
92 *
93 * FUNCTION:    AcpiGetTimer
94 *
95 * PARAMETERS:  Ticks               - Where the timer value is returned
96 *
97 * RETURN:      Status and current timer value (ticks)
98 *
99 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
100 *
101 ******************************************************************************/
102
103ACPI_STATUS
104AcpiGetTimer (
105    UINT32                  *Ticks)
106{
107    ACPI_STATUS             Status;
108
109
110    ACPI_FUNCTION_TRACE (AcpiGetTimer);
111
112
113    if (!Ticks)
114    {
115        return_ACPI_STATUS (AE_BAD_PARAMETER);
116    }
117
118    Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
119
120    return_ACPI_STATUS (Status);
121}
122
123ACPI_EXPORT_SYMBOL (AcpiGetTimer)
124
125
126/******************************************************************************
127 *
128 * FUNCTION:    AcpiGetTimerDuration
129 *
130 * PARAMETERS:  StartTicks          - Starting timestamp
131 *              EndTicks            - End timestamp
132 *              TimeElapsed         - Where the elapsed time is returned
133 *
134 * RETURN:      Status and TimeElapsed
135 *
136 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
137 *              PM Timer time stamps, taking into account the possibility of
138 *              rollovers, the timer resolution, and timer frequency.
139 *
140 *              The PM Timer's clock ticks at roughly 3.6 times per
141 *              _microsecond_, and its clock continues through Cx state
142 *              transitions (unlike many CPU timestamp counters) -- making it
143 *              a versatile and accurate timer.
144 *
145 *              Note that this function accommodates only a single timer
146 *              rollover.  Thus for 24-bit timers, this function should only
147 *              be used for calculating durations less than ~4.6 seconds
148 *              (~20 minutes for 32-bit timers) -- calculations below:
149 *
150 *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
151 *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
152 *
153 ******************************************************************************/
154
155ACPI_STATUS
156AcpiGetTimerDuration (
157    UINT32                  StartTicks,
158    UINT32                  EndTicks,
159    UINT32                  *TimeElapsed)
160{
161    ACPI_STATUS             Status;
162    UINT32                  DeltaTicks;
163    UINT64                  Quotient;
164
165
166    ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
167
168
169    if (!TimeElapsed)
170    {
171        return_ACPI_STATUS (AE_BAD_PARAMETER);
172    }
173
174    /*
175     * Compute Tick Delta:
176     * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
177     */
178    if (StartTicks < EndTicks)
179    {
180        DeltaTicks = EndTicks - StartTicks;
181    }
182    else if (StartTicks > EndTicks)
183    {
184        if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
185        {
186            /* 24-bit Timer */
187
188            DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
189        }
190        else
191        {
192            /* 32-bit Timer */
193
194            DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
195        }
196    }
197    else /* StartTicks == EndTicks */
198    {
199        *TimeElapsed = 0;
200        return_ACPI_STATUS (AE_OK);
201    }
202
203    /*
204     * Compute Duration (Requires a 64-bit multiply and divide):
205     *
206     * TimeElapsed = (DeltaTicks * 1000000) / PM_TIMER_FREQUENCY;
207     */
208    Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * 1000000,
209                PM_TIMER_FREQUENCY, &Quotient, NULL);
210
211    *TimeElapsed = (UINT32) Quotient;
212    return_ACPI_STATUS (Status);
213}
214
215ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
216
217