diff options
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 00000000000..b7f522c8f02 --- /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 "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) | ||
