blob: b7f522c8f023d48686d40d7267196d6d296b6e44 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001
2/******************************************************************************
3 *
4 * Name: hwtimer.c - ACPI Power Management Timer Interface
5 *
6 *****************************************************************************/
7
8/*
Len Brown75a44ce2008-04-23 23:00:13 -04009 * Copyright (C) 2000 - 2008, Intel Corp.
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#include <acpi/acpi.h>
Len Browne2f7a772009-01-09 00:30:03 -050046#include "accommon.h"
Linus Torvalds1da177e2005-04-16 15:20:36 -070047
48#define _COMPONENT ACPI_HARDWARE
Len Brown4be44fc2005-08-05 00:44:28 -040049ACPI_MODULE_NAME("hwtimer")
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
51/******************************************************************************
52 *
53 * FUNCTION: acpi_get_timer_resolution
54 *
55 * PARAMETERS: Resolution - Where the resolution is returned
56 *
57 * RETURN: Status and timer resolution
58 *
59 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
60 *
61 ******************************************************************************/
Len Brown4be44fc2005-08-05 00:44:28 -040062acpi_status acpi_get_timer_resolution(u32 * resolution)
Linus Torvalds1da177e2005-04-16 15:20:36 -070063{
Bob Mooreb229cf92006-04-21 17:15:00 -040064 ACPI_FUNCTION_TRACE(acpi_get_timer_resolution);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
66 if (!resolution) {
Len Brown4be44fc2005-08-05 00:44:28 -040067 return_ACPI_STATUS(AE_BAD_PARAMETER);
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 }
69
Bob Mooref3d2e782007-02-02 19:48:18 +030070 if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 *resolution = 24;
Len Brown4be44fc2005-08-05 00:44:28 -040072 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -070073 *resolution = 32;
74 }
75
Len Brown4be44fc2005-08-05 00:44:28 -040076 return_ACPI_STATUS(AE_OK);
Linus Torvalds1da177e2005-04-16 15:20:36 -070077}
78
Bob Moore83135242006-10-03 00:00:00 -040079ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution)
80
Linus Torvalds1da177e2005-04-16 15:20:36 -070081/******************************************************************************
82 *
83 * FUNCTION: acpi_get_timer
84 *
85 * PARAMETERS: Ticks - Where the timer value is returned
86 *
Robert Moore44f6c012005-04-18 22:49:35 -040087 * RETURN: Status and current timer value (ticks)
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 *
89 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
90 *
91 ******************************************************************************/
Len Brown4be44fc2005-08-05 00:44:28 -040092acpi_status acpi_get_timer(u32 * ticks)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
Len Brown4be44fc2005-08-05 00:44:28 -040094 acpi_status status;
Linus Torvalds1da177e2005-04-16 15:20:36 -070095
Bob Mooreb229cf92006-04-21 17:15:00 -040096 ACPI_FUNCTION_TRACE(acpi_get_timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -070097
98 if (!ticks) {
Len Brown4be44fc2005-08-05 00:44:28 -040099 return_ACPI_STATUS(AE_BAD_PARAMETER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100 }
101
Bob Mooref3d2e782007-02-02 19:48:18 +0300102 status =
103 acpi_hw_low_level_read(32, ticks, &acpi_gbl_FADT.xpm_timer_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104
Len Brown4be44fc2005-08-05 00:44:28 -0400105 return_ACPI_STATUS(status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107
Bob Moore83135242006-10-03 00:00:00 -0400108ACPI_EXPORT_SYMBOL(acpi_get_timer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109
110/******************************************************************************
111 *
112 * FUNCTION: acpi_get_timer_duration
113 *
114 * PARAMETERS: start_ticks - Starting timestamp
115 * end_ticks - End timestamp
116 * time_elapsed - Where the elapsed time is returned
117 *
118 * RETURN: Status and time_elapsed
119 *
120 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
121 * PM Timer time stamps, taking into account the possibility of
122 * rollovers, the timer resolution, and timer frequency.
123 *
124 * The PM Timer's clock ticks at roughly 3.6 times per
125 * _microsecond_, and its clock continues through Cx state
126 * transitions (unlike many CPU timestamp counters) -- making it
127 * a versatile and accurate timer.
128 *
129 * Note that this function accommodates only a single timer
130 * rollover. Thus for 24-bit timers, this function should only
131 * be used for calculating durations less than ~4.6 seconds
132 * (~20 minutes for 32-bit timers) -- calculations below:
133 *
134 * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
135 * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
136 *
137 ******************************************************************************/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138acpi_status
Len Brown4be44fc2005-08-05 00:44:28 -0400139acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140{
Len Brown4be44fc2005-08-05 00:44:28 -0400141 acpi_status status;
142 u32 delta_ticks;
143 acpi_integer quotient;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144
Bob Mooreb229cf92006-04-21 17:15:00 -0400145 ACPI_FUNCTION_TRACE(acpi_get_timer_duration);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146
147 if (!time_elapsed) {
Len Brown4be44fc2005-08-05 00:44:28 -0400148 return_ACPI_STATUS(AE_BAD_PARAMETER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 }
150
151 /*
152 * Compute Tick Delta:
153 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
154 */
155 if (start_ticks < end_ticks) {
156 delta_ticks = end_ticks - start_ticks;
Len Brown4be44fc2005-08-05 00:44:28 -0400157 } else if (start_ticks > end_ticks) {
Bob Mooref3d2e782007-02-02 19:48:18 +0300158 if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
Bob Moore52fc0b02006-10-02 00:00:00 -0400159
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 /* 24-bit Timer */
161
Len Brown4be44fc2005-08-05 00:44:28 -0400162 delta_ticks =
163 (((0x00FFFFFF - start_ticks) +
164 end_ticks) & 0x00FFFFFF);
165 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 /* 32-bit Timer */
167
168 delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
169 }
Len Brown4be44fc2005-08-05 00:44:28 -0400170 } else { /* start_ticks == end_ticks */
171
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 *time_elapsed = 0;
Len Brown4be44fc2005-08-05 00:44:28 -0400173 return_ACPI_STATUS(AE_OK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 }
175
176 /*
177 * Compute Duration (Requires a 64-bit multiply and divide):
178 *
179 * time_elapsed = (delta_ticks * 1000000) / PM_TIMER_FREQUENCY;
180 */
Len Brown4be44fc2005-08-05 00:44:28 -0400181 status = acpi_ut_short_divide(((u64) delta_ticks) * 1000000,
182 PM_TIMER_FREQUENCY, &quotient, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700183
184 *time_elapsed = (u32) quotient;
Len Brown4be44fc2005-08-05 00:44:28 -0400185 return_ACPI_STATUS(status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186}
Robert Moore44f6c012005-04-18 22:49:35 -0400187
Bob Moore83135242006-10-03 00:00:00 -0400188ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)