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#include <contrib/dev/acpica/include/acpi.h>
45#include <contrib/dev/acpica/include/accommon.h>
46
47#define _COMPONENT          ACPI_HARDWARE
48        ACPI_MODULE_NAME    ("hwtimer")
49
50
51#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
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    /* ACPI 5.0A: PM Timer is optional */
119
120    if (!AcpiGbl_FADT.XPmTimerBlock.Address)
121    {
122        return_ACPI_STATUS (AE_SUPPORT);
123    }
124
125    Status = AcpiHwRead (Ticks, &AcpiGbl_FADT.XPmTimerBlock);
126    return_ACPI_STATUS (Status);
127}
128
129ACPI_EXPORT_SYMBOL (AcpiGetTimer)
130
131
132/******************************************************************************
133 *
134 * FUNCTION:    AcpiGetTimerDuration
135 *
136 * PARAMETERS:  StartTicks          - Starting timestamp
137 *              EndTicks            - End timestamp
138 *              TimeElapsed         - Where the elapsed time is returned
139 *
140 * RETURN:      Status and TimeElapsed
141 *
142 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
143 *              PM Timer time stamps, taking into account the possibility of
144 *              rollovers, the timer resolution, and timer frequency.
145 *
146 *              The PM Timer's clock ticks at roughly 3.6 times per
147 *              _microsecond_, and its clock continues through Cx state
148 *              transitions (unlike many CPU timestamp counters) -- making it
149 *              a versatile and accurate timer.
150 *
151 *              Note that this function accommodates only a single timer
152 *              rollover. Thus for 24-bit timers, this function should only
153 *              be used for calculating durations less than ~4.6 seconds
154 *              (~20 minutes for 32-bit timers) -- calculations below:
155 *
156 *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
157 *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
158 *
159 ******************************************************************************/
160
161ACPI_STATUS
162AcpiGetTimerDuration (
163    UINT32                  StartTicks,
164    UINT32                  EndTicks,
165    UINT32                  *TimeElapsed)
166{
167    ACPI_STATUS             Status;
168    UINT32                  DeltaTicks;
169    UINT64                  Quotient;
170
171
172    ACPI_FUNCTION_TRACE (AcpiGetTimerDuration);
173
174
175    if (!TimeElapsed)
176    {
177        return_ACPI_STATUS (AE_BAD_PARAMETER);
178    }
179
180    /* ACPI 5.0A: PM Timer is optional */
181
182    if (!AcpiGbl_FADT.XPmTimerBlock.Address)
183    {
184        return_ACPI_STATUS (AE_SUPPORT);
185    }
186
187    /*
188     * Compute Tick Delta:
189     * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
190     */
191    if (StartTicks < EndTicks)
192    {
193        DeltaTicks = EndTicks - StartTicks;
194    }
195    else if (StartTicks > EndTicks)
196    {
197        if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) == 0)
198        {
199            /* 24-bit Timer */
200
201            DeltaTicks = (((0x00FFFFFF - StartTicks) + EndTicks) & 0x00FFFFFF);
202        }
203        else
204        {
205            /* 32-bit Timer */
206
207            DeltaTicks = (0xFFFFFFFF - StartTicks) + EndTicks;
208        }
209    }
210    else /* StartTicks == EndTicks */
211    {
212        *TimeElapsed = 0;
213        return_ACPI_STATUS (AE_OK);
214    }
215
216    /*
217     * Compute Duration (Requires a 64-bit multiply and divide):
218     *
219     * TimeElapsed (microseconds) =
220     *  (DeltaTicks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
221     */
222    Status = AcpiUtShortDivide (((UINT64) DeltaTicks) * ACPI_USEC_PER_SEC,
223                ACPI_PM_TIMER_FREQUENCY, &Quotient, NULL);
224
225    *TimeElapsed = (UINT32) Quotient;
226    return_ACPI_STATUS (Status);
227}
228
229ACPI_EXPORT_SYMBOL (AcpiGetTimerDuration)
230
231#endif /* !ACPI_REDUCED_HARDWARE */
232