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1da177e4 LT |
1 | |
2 | /****************************************************************************** | |
3 | * | |
4 | * Name: hwtimer.c - ACPI Power Management Timer Interface | |
5 | * | |
6 | *****************************************************************************/ | |
7 | ||
8 | /* | |
9 | * Copyright (C) 2000 - 2005, R. Byron Moore | |
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 <linux/module.h> | |
1da177e4 LT |
46 | #include <acpi/acpi.h> |
47 | ||
48 | #define _COMPONENT ACPI_HARDWARE | |
4be44fcd | 49 | ACPI_MODULE_NAME("hwtimer") |
1da177e4 LT |
50 | |
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 | ******************************************************************************/ | |
4be44fcd | 62 | acpi_status acpi_get_timer_resolution(u32 * resolution) |
1da177e4 | 63 | { |
4be44fcd | 64 | ACPI_FUNCTION_TRACE("acpi_get_timer_resolution"); |
1da177e4 LT |
65 | |
66 | if (!resolution) { | |
4be44fcd | 67 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
1da177e4 LT |
68 | } |
69 | ||
70 | if (0 == acpi_gbl_FADT->tmr_val_ext) { | |
71 | *resolution = 24; | |
4be44fcd | 72 | } else { |
1da177e4 LT |
73 | *resolution = 32; |
74 | } | |
75 | ||
4be44fcd | 76 | return_ACPI_STATUS(AE_OK); |
1da177e4 LT |
77 | } |
78 | ||
1da177e4 LT |
79 | /****************************************************************************** |
80 | * | |
81 | * FUNCTION: acpi_get_timer | |
82 | * | |
83 | * PARAMETERS: Ticks - Where the timer value is returned | |
84 | * | |
44f6c012 | 85 | * RETURN: Status and current timer value (ticks) |
1da177e4 LT |
86 | * |
87 | * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). | |
88 | * | |
89 | ******************************************************************************/ | |
90 | ||
4be44fcd | 91 | acpi_status acpi_get_timer(u32 * ticks) |
1da177e4 | 92 | { |
4be44fcd | 93 | acpi_status status; |
1da177e4 | 94 | |
4be44fcd | 95 | ACPI_FUNCTION_TRACE("acpi_get_timer"); |
1da177e4 LT |
96 | |
97 | if (!ticks) { | |
4be44fcd | 98 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
1da177e4 LT |
99 | } |
100 | ||
4be44fcd | 101 | status = acpi_hw_low_level_read(32, ticks, &acpi_gbl_FADT->xpm_tmr_blk); |
1da177e4 | 102 | |
4be44fcd | 103 | return_ACPI_STATUS(status); |
1da177e4 | 104 | } |
1da177e4 | 105 | |
4be44fcd | 106 | EXPORT_SYMBOL(acpi_get_timer); |
1da177e4 LT |
107 | |
108 | /****************************************************************************** | |
109 | * | |
110 | * FUNCTION: acpi_get_timer_duration | |
111 | * | |
112 | * PARAMETERS: start_ticks - Starting timestamp | |
113 | * end_ticks - End timestamp | |
114 | * time_elapsed - Where the elapsed time is returned | |
115 | * | |
116 | * RETURN: Status and time_elapsed | |
117 | * | |
118 | * DESCRIPTION: Computes the time elapsed (in microseconds) between two | |
119 | * PM Timer time stamps, taking into account the possibility of | |
120 | * rollovers, the timer resolution, and timer frequency. | |
121 | * | |
122 | * The PM Timer's clock ticks at roughly 3.6 times per | |
123 | * _microsecond_, and its clock continues through Cx state | |
124 | * transitions (unlike many CPU timestamp counters) -- making it | |
125 | * a versatile and accurate timer. | |
126 | * | |
127 | * Note that this function accommodates only a single timer | |
128 | * rollover. Thus for 24-bit timers, this function should only | |
129 | * be used for calculating durations less than ~4.6 seconds | |
130 | * (~20 minutes for 32-bit timers) -- calculations below: | |
131 | * | |
132 | * 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec | |
133 | * 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes | |
134 | * | |
135 | ******************************************************************************/ | |
136 | ||
137 | acpi_status | |
4be44fcd | 138 | acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed) |
1da177e4 | 139 | { |
4be44fcd LB |
140 | acpi_status status; |
141 | u32 delta_ticks; | |
142 | acpi_integer quotient; | |
1da177e4 | 143 | |
4be44fcd | 144 | ACPI_FUNCTION_TRACE("acpi_get_timer_duration"); |
1da177e4 LT |
145 | |
146 | if (!time_elapsed) { | |
4be44fcd | 147 | return_ACPI_STATUS(AE_BAD_PARAMETER); |
1da177e4 LT |
148 | } |
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; | |
4be44fcd | 156 | } else if (start_ticks > end_ticks) { |
1da177e4 LT |
157 | if (0 == acpi_gbl_FADT->tmr_val_ext) { |
158 | /* 24-bit Timer */ | |
159 | ||
4be44fcd LB |
160 | delta_ticks = |
161 | (((0x00FFFFFF - start_ticks) + | |
162 | end_ticks) & 0x00FFFFFF); | |
163 | } else { | |
1da177e4 LT |
164 | /* 32-bit Timer */ |
165 | ||
166 | delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks; | |
167 | } | |
4be44fcd LB |
168 | } else { /* start_ticks == end_ticks */ |
169 | ||
1da177e4 | 170 | *time_elapsed = 0; |
4be44fcd | 171 | return_ACPI_STATUS(AE_OK); |
1da177e4 LT |
172 | } |
173 | ||
174 | /* | |
175 | * Compute Duration (Requires a 64-bit multiply and divide): | |
176 | * | |
177 | * time_elapsed = (delta_ticks * 1000000) / PM_TIMER_FREQUENCY; | |
178 | */ | |
4be44fcd LB |
179 | status = acpi_ut_short_divide(((u64) delta_ticks) * 1000000, |
180 | PM_TIMER_FREQUENCY, "ient, NULL); | |
1da177e4 LT |
181 | |
182 | *time_elapsed = (u32) quotient; | |
4be44fcd | 183 | return_ACPI_STATUS(status); |
1da177e4 | 184 | } |
44f6c012 | 185 | |
1da177e4 | 186 | EXPORT_SYMBOL(acpi_get_timer_duration); |