WebSVN – Kolibri OS – Blame – /drivers/acpi/acpica/hwtimer.c

Rev	Author	Line No.	Line
6595	serge	1	/******************************************************************************
		2	*
		3	* Name: hwtimer.c - ACPI Power Management Timer Interface
		4	*
		5	*****************************************************************************/
		6
		7	/*
		8	* Copyright (C) 2000 - 2015, Intel Corp.
		9	* All rights reserved.
		10	*
		11	* Redistribution and use in source and binary forms, with or without
		12	* modification, are permitted provided that the following conditions
		13	* are met:
		14	* 1. Redistributions of source code must retain the above copyright
		15	* notice, this list of conditions, and the following disclaimer,
		16	* without modification.
		17	* 2. Redistributions in binary form must reproduce at minimum a disclaimer
		18	* substantially similar to the "NO WARRANTY" disclaimer below
		19	* ("Disclaimer") and any redistribution must be conditioned upon
		20	* including a substantially similar Disclaimer requirement for further
		21	* binary redistribution.
		22	* 3. Neither the names of the above-listed copyright holders nor the names
		23	* of any contributors may be used to endorse or promote products derived
		24	* from this software without specific prior written permission.
		25	*
		26	* Alternatively, this software may be distributed under the terms of the
		27	* GNU General Public License ("GPL") version 2 as published by the Free
		28	* Software Foundation.
		29	*
		30	* NO WARRANTY
		31	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
		32	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
		33	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
		34	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
		35	* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
		36	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
		37	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
		38	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
		39	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
		40	* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
		41	* POSSIBILITY OF SUCH DAMAGES.
		42	*/
		43
		44	#define EXPORT_ACPI_INTERFACES
		45
		46	#include
		47	#include "accommon.h"
		48
		49	#define _COMPONENT ACPI_HARDWARE
		50	ACPI_MODULE_NAME("hwtimer")
		51
		52	#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
		53	/******************************************************************************
		54	*
		55	* FUNCTION: acpi_get_timer_resolution
		56	*
		57	* PARAMETERS: resolution - Where the resolution is returned
		58	*
		59	* RETURN: Status and timer resolution
		60	*
		61	* DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
		62	*
		63	******************************************************************************/
		64	acpi_status acpi_get_timer_resolution(u32 * resolution)
		65	{
		66	ACPI_FUNCTION_TRACE(acpi_get_timer_resolution);
		67
		68	if (!resolution) {
		69	return_ACPI_STATUS(AE_BAD_PARAMETER);
		70	}
		71
		72	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
		73	*resolution = 24;
		74	} else {
		75	*resolution = 32;
		76	}
		77
		78	return_ACPI_STATUS(AE_OK);
		79	}
		80
		81	ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution)
		82
		83	/******************************************************************************
		84	*
		85	* FUNCTION: acpi_get_timer
		86	*
		87	* PARAMETERS: ticks - Where the timer value is returned
		88	*
		89	* RETURN: Status and current timer value (ticks)
		90	*
		91	* DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
		92	*
		93	******************************************************************************/
		94	acpi_status acpi_get_timer(u32 * ticks)
		95	{
		96	acpi_status status;
		97
		98	ACPI_FUNCTION_TRACE(acpi_get_timer);
		99
		100	if (!ticks) {
		101	return_ACPI_STATUS(AE_BAD_PARAMETER);
		102	}
		103
		104	/* ACPI 5.0A: PM Timer is optional */
		105
		106	if (!acpi_gbl_FADT.xpm_timer_block.address) {
		107	return_ACPI_STATUS(AE_SUPPORT);
		108	}
		109
		110	status = acpi_hw_read(ticks, &acpi_gbl_FADT.xpm_timer_block);
		111	return_ACPI_STATUS(status);
		112	}
		113
		114	ACPI_EXPORT_SYMBOL(acpi_get_timer)
		115
		116	/******************************************************************************
		117	*
		118	* FUNCTION: acpi_get_timer_duration
		119	*
		120	* PARAMETERS: start_ticks - Starting timestamp
		121	* end_ticks - End timestamp
		122	* time_elapsed - Where the elapsed time is returned
		123	*
		124	* RETURN: Status and time_elapsed
		125	*
		126	* DESCRIPTION: Computes the time elapsed (in microseconds) between two
		127	* PM Timer time stamps, taking into account the possibility of
		128	* rollovers, the timer resolution, and timer frequency.
		129	*
		130	* The PM Timer's clock ticks at roughly 3.6 times per
		131	* _microsecond_, and its clock continues through Cx state
		132	* transitions (unlike many CPU timestamp counters) -- making it
		133	* a versatile and accurate timer.
		134	*
		135	* Note that this function accommodates only a single timer
		136	* rollover. Thus for 24-bit timers, this function should only
		137	* be used for calculating durations less than ~4.6 seconds
		138	* (~20 minutes for 32-bit timers) -- calculations below:
		139	*
		140	* 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
		141	* 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
		142	*
		143	******************************************************************************/
		144	acpi_status
		145	acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
		146	{
		147	acpi_status status;
		148	u32 delta_ticks;
		149	u64 quotient;
		150
		151	ACPI_FUNCTION_TRACE(acpi_get_timer_duration);
		152
		153	if (!time_elapsed) {
		154	return_ACPI_STATUS(AE_BAD_PARAMETER);
		155	}
		156
		157	/* ACPI 5.0A: PM Timer is optional */
		158
		159	if (!acpi_gbl_FADT.xpm_timer_block.address) {
		160	return_ACPI_STATUS(AE_SUPPORT);
		161	}
		162
		163	/*
		164	* Compute Tick Delta:
		165	* Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
		166	*/
		167	if (start_ticks < end_ticks) {
		168	delta_ticks = end_ticks - start_ticks;
		169	} else if (start_ticks > end_ticks) {
		170	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
		171
		172	/* 24-bit Timer */
		173
		174	delta_ticks =
		175	(((0x00FFFFFF - start_ticks) +
		176	end_ticks) & 0x00FFFFFF);
		177	} else {
		178	/* 32-bit Timer */
		179
		180	delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
		181	}
		182	} else { /* start_ticks == end_ticks */
		183
		184	*time_elapsed = 0;
		185	return_ACPI_STATUS(AE_OK);
		186	}
		187
		188	/*
		189	* Compute Duration (Requires a 64-bit multiply and divide):
		190	*
		191	* time_elapsed (microseconds) =
		192	* (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
		193	*/
		194	status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC,
		195	ACPI_PM_TIMER_FREQUENCY, "ient, NULL);
		196
		197	*time_elapsed = (u32) quotient;
		198	return_ACPI_STATUS(status);
		199	}
		200
		201	ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)
		202	#endif /* !ACPI_REDUCED_HARDWARE */

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(root)/drivers/acpi/acpica/hwtimer.c – Rev 6595