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Diffstat (limited to 'drivers/acpi/acpica/hwtimer.c')
-rw-r--r-- | drivers/acpi/acpica/hwtimer.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/hwtimer.c b/drivers/acpi/acpica/hwtimer.c new file mode 100644 index 000000000000..d1eac2aad728 --- /dev/null +++ b/drivers/acpi/acpica/hwtimer.c | |||
@@ -0,0 +1,188 @@ | |||
1 | |||
2 | /****************************************************************************** | ||
3 | * | ||
4 | * Name: hwtimer.c - ACPI Power Management Timer Interface | ||
5 | * | ||
6 | *****************************************************************************/ | ||
7 | |||
8 | /* | ||
9 | * Copyright (C) 2000 - 2008, 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 <acpi/acpi.h> | ||
46 | #include <acpi/accommon.h> | ||
47 | |||
48 | #define _COMPONENT ACPI_HARDWARE | ||
49 | ACPI_MODULE_NAME("hwtimer") | ||
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 | ******************************************************************************/ | ||
62 | acpi_status acpi_get_timer_resolution(u32 * resolution) | ||
63 | { | ||
64 | ACPI_FUNCTION_TRACE(acpi_get_timer_resolution); | ||
65 | |||
66 | if (!resolution) { | ||
67 | return_ACPI_STATUS(AE_BAD_PARAMETER); | ||
68 | } | ||
69 | |||
70 | if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { | ||
71 | *resolution = 24; | ||
72 | } else { | ||
73 | *resolution = 32; | ||
74 | } | ||
75 | |||
76 | return_ACPI_STATUS(AE_OK); | ||
77 | } | ||
78 | |||
79 | ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution) | ||
80 | |||
81 | /****************************************************************************** | ||
82 | * | ||
83 | * FUNCTION: acpi_get_timer | ||
84 | * | ||
85 | * PARAMETERS: Ticks - Where the timer value is returned | ||
86 | * | ||
87 | * RETURN: Status and current timer value (ticks) | ||
88 | * | ||
89 | * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks). | ||
90 | * | ||
91 | ******************************************************************************/ | ||
92 | acpi_status acpi_get_timer(u32 * ticks) | ||
93 | { | ||
94 | acpi_status status; | ||
95 | |||
96 | ACPI_FUNCTION_TRACE(acpi_get_timer); | ||
97 | |||
98 | if (!ticks) { | ||
99 | return_ACPI_STATUS(AE_BAD_PARAMETER); | ||
100 | } | ||
101 | |||
102 | status = | ||
103 | acpi_hw_low_level_read(32, ticks, &acpi_gbl_FADT.xpm_timer_block); | ||
104 | |||
105 | return_ACPI_STATUS(status); | ||
106 | } | ||
107 | |||
108 | ACPI_EXPORT_SYMBOL(acpi_get_timer) | ||
109 | |||
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 | ******************************************************************************/ | ||
138 | acpi_status | ||
139 | acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed) | ||
140 | { | ||
141 | acpi_status status; | ||
142 | u32 delta_ticks; | ||
143 | acpi_integer quotient; | ||
144 | |||
145 | ACPI_FUNCTION_TRACE(acpi_get_timer_duration); | ||
146 | |||
147 | if (!time_elapsed) { | ||
148 | return_ACPI_STATUS(AE_BAD_PARAMETER); | ||
149 | } | ||
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; | ||
157 | } else if (start_ticks > end_ticks) { | ||
158 | if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) { | ||
159 | |||
160 | /* 24-bit Timer */ | ||
161 | |||
162 | delta_ticks = | ||
163 | (((0x00FFFFFF - start_ticks) + | ||
164 | end_ticks) & 0x00FFFFFF); | ||
165 | } else { | ||
166 | /* 32-bit Timer */ | ||
167 | |||
168 | delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks; | ||
169 | } | ||
170 | } else { /* start_ticks == end_ticks */ | ||
171 | |||
172 | *time_elapsed = 0; | ||
173 | return_ACPI_STATUS(AE_OK); | ||
174 | } | ||
175 | |||
176 | /* | ||
177 | * Compute Duration (Requires a 64-bit multiply and divide): | ||
178 | * | ||
179 | * time_elapsed = (delta_ticks * 1000000) / PM_TIMER_FREQUENCY; | ||
180 | */ | ||
181 | status = acpi_ut_short_divide(((u64) delta_ticks) * 1000000, | ||
182 | PM_TIMER_FREQUENCY, "ient, NULL); | ||
183 | |||
184 | *time_elapsed = (u32) quotient; | ||
185 | return_ACPI_STATUS(status); | ||
186 | } | ||
187 | |||
188 | ACPI_EXPORT_SYMBOL(acpi_get_timer_duration) | ||