blob: c32eab696acd11f4fad79daab380c9d189faaf71 [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/*
Bob Moore6c9deb72007-02-02 19:48:24 +03009 * Copyright (C) 2000 - 2007, R. Byron Moore
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>
46
47#define _COMPONENT ACPI_HARDWARE
Len Brown4be44fc2005-08-05 00:44:28 -040048ACPI_MODULE_NAME("hwtimer")
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50/******************************************************************************
51 *
52 * FUNCTION: acpi_get_timer_resolution
53 *
54 * PARAMETERS: Resolution - Where the resolution is returned
55 *
56 * RETURN: Status and timer resolution
57 *
58 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
59 *
60 ******************************************************************************/
Len Brown4be44fc2005-08-05 00:44:28 -040061acpi_status acpi_get_timer_resolution(u32 * resolution)
Linus Torvalds1da177e2005-04-16 15:20:36 -070062{
Bob Mooreb229cf92006-04-21 17:15:00 -040063 ACPI_FUNCTION_TRACE(acpi_get_timer_resolution);
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
65 if (!resolution) {
Len Brown4be44fc2005-08-05 00:44:28 -040066 return_ACPI_STATUS(AE_BAD_PARAMETER);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 }
68
Bob Mooref3d2e782007-02-02 19:48:18 +030069 if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070070 *resolution = 24;
Len Brown4be44fc2005-08-05 00:44:28 -040071 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -070072 *resolution = 32;
73 }
74
Len Brown4be44fc2005-08-05 00:44:28 -040075 return_ACPI_STATUS(AE_OK);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076}
77
Bob Moore83135242006-10-03 00:00:00 -040078ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution)
79
Linus Torvalds1da177e2005-04-16 15:20:36 -070080/******************************************************************************
81 *
82 * FUNCTION: acpi_get_timer
83 *
84 * PARAMETERS: Ticks - Where the timer value is returned
85 *
Robert Moore44f6c012005-04-18 22:49:35 -040086 * RETURN: Status and current timer value (ticks)
Linus Torvalds1da177e2005-04-16 15:20:36 -070087 *
88 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
89 *
90 ******************************************************************************/
Len Brown4be44fc2005-08-05 00:44:28 -040091acpi_status acpi_get_timer(u32 * ticks)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
Len Brown4be44fc2005-08-05 00:44:28 -040093 acpi_status status;
Linus Torvalds1da177e2005-04-16 15:20:36 -070094
Bob Mooreb229cf92006-04-21 17:15:00 -040095 ACPI_FUNCTION_TRACE(acpi_get_timer);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 if (!ticks) {
Len Brown4be44fc2005-08-05 00:44:28 -040098 return_ACPI_STATUS(AE_BAD_PARAMETER);
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 }
100
Bob Mooref3d2e782007-02-02 19:48:18 +0300101 status =
102 acpi_hw_low_level_read(32, ticks, &acpi_gbl_FADT.xpm_timer_block);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103
Len Brown4be44fc2005-08-05 00:44:28 -0400104 return_ACPI_STATUS(status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
Bob Moore83135242006-10-03 00:00:00 -0400107ACPI_EXPORT_SYMBOL(acpi_get_timer)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109/******************************************************************************
110 *
111 * FUNCTION: acpi_get_timer_duration
112 *
113 * PARAMETERS: start_ticks - Starting timestamp
114 * end_ticks - End timestamp
115 * time_elapsed - Where the elapsed time is returned
116 *
117 * RETURN: Status and time_elapsed
118 *
119 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
120 * PM Timer time stamps, taking into account the possibility of
121 * rollovers, the timer resolution, and timer frequency.
122 *
123 * The PM Timer's clock ticks at roughly 3.6 times per
124 * _microsecond_, and its clock continues through Cx state
125 * transitions (unlike many CPU timestamp counters) -- making it
126 * a versatile and accurate timer.
127 *
128 * Note that this function accommodates only a single timer
129 * rollover. Thus for 24-bit timers, this function should only
130 * be used for calculating durations less than ~4.6 seconds
131 * (~20 minutes for 32-bit timers) -- calculations below:
132 *
133 * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
134 * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
135 *
136 ******************************************************************************/
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137acpi_status
Len Brown4be44fc2005-08-05 00:44:28 -0400138acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
Len Brown4be44fc2005-08-05 00:44:28 -0400140 acpi_status status;
141 u32 delta_ticks;
142 acpi_integer quotient;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Bob Mooreb229cf92006-04-21 17:15:00 -0400144 ACPI_FUNCTION_TRACE(acpi_get_timer_duration);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146 if (!time_elapsed) {
Len Brown4be44fc2005-08-05 00:44:28 -0400147 return_ACPI_STATUS(AE_BAD_PARAMETER);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 }
149
150 /*
151 * Compute Tick Delta:
152 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
153 */
154 if (start_ticks < end_ticks) {
155 delta_ticks = end_ticks - start_ticks;
Len Brown4be44fc2005-08-05 00:44:28 -0400156 } else if (start_ticks > end_ticks) {
Bob Mooref3d2e782007-02-02 19:48:18 +0300157 if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
Bob Moore52fc0b02006-10-02 00:00:00 -0400158
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159 /* 24-bit Timer */
160
Len Brown4be44fc2005-08-05 00:44:28 -0400161 delta_ticks =
162 (((0x00FFFFFF - start_ticks) +
163 end_ticks) & 0x00FFFFFF);
164 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 /* 32-bit Timer */
166
167 delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
168 }
Len Brown4be44fc2005-08-05 00:44:28 -0400169 } else { /* start_ticks == end_ticks */
170
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 *time_elapsed = 0;
Len Brown4be44fc2005-08-05 00:44:28 -0400172 return_ACPI_STATUS(AE_OK);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173 }
174
175 /*
176 * Compute Duration (Requires a 64-bit multiply and divide):
177 *
178 * time_elapsed = (delta_ticks * 1000000) / PM_TIMER_FREQUENCY;
179 */
Len Brown4be44fc2005-08-05 00:44:28 -0400180 status = acpi_ut_short_divide(((u64) delta_ticks) * 1000000,
181 PM_TIMER_FREQUENCY, &quotient, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182
183 *time_elapsed = (u32) quotient;
Len Brown4be44fc2005-08-05 00:44:28 -0400184 return_ACPI_STATUS(status);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185}
Robert Moore44f6c012005-04-18 22:49:35 -0400186
Bob Moore83135242006-10-03 00:00:00 -0400187ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)