[deliverable/linux.git] / drivers / acpi / acpica / hwtimer.c

/******************************************************************************
 *
 * Name: hwtimer.c - ACPI Power Management Timer Interface
 *
 *****************************************************************************/

/*
 * Copyright (C) 2000 - 2013, Intel Corp.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 */

#include <linux/export.h>
#include <acpi/acpi.h>
#include "accommon.h"

#define _COMPONENT          ACPI_HARDWARE
ACPI_MODULE_NAME("hwtimer")

#if (!ACPI_REDUCED_HARDWARE)	/* Entire module */
/******************************************************************************
 *
 * FUNCTION:    acpi_get_timer_resolution
 *
 * PARAMETERS:  resolution          - Where the resolution is returned
 *
 * RETURN:      Status and timer resolution
 *
 * DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
 *
 ******************************************************************************/
acpi_status acpi_get_timer_resolution(u32 * resolution)
{
	ACPI_FUNCTION_TRACE(acpi_get_timer_resolution);

	if (!resolution) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
		*resolution = 24;
	} else {
		*resolution = 32;
	}

	return_ACPI_STATUS(AE_OK);
}

ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution)

/******************************************************************************
 *
 * FUNCTION:    acpi_get_timer
 *
 * PARAMETERS:  ticks               - Where the timer value is returned
 *
 * RETURN:      Status and current timer value (ticks)
 *
 * DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
 *
 ******************************************************************************/
acpi_status acpi_get_timer(u32 * ticks)
{
	acpi_status status;

	ACPI_FUNCTION_TRACE(acpi_get_timer);

	if (!ticks) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	/* ACPI 5.0A: PM Timer is optional */

	if (!acpi_gbl_FADT.xpm_timer_block.address) {
		return_ACPI_STATUS(AE_SUPPORT);
	}

	status = acpi_hw_read(ticks, &acpi_gbl_FADT.xpm_timer_block);
	return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_get_timer)

/******************************************************************************
 *
 * FUNCTION:    acpi_get_timer_duration
 *
 * PARAMETERS:  start_ticks         - Starting timestamp
 *              end_ticks           - End timestamp
 *              time_elapsed        - Where the elapsed time is returned
 *
 * RETURN:      Status and time_elapsed
 *
 * DESCRIPTION: Computes the time elapsed (in microseconds) between two
 *              PM Timer time stamps, taking into account the possibility of
 *              rollovers, the timer resolution, and timer frequency.
 *
 *              The PM Timer's clock ticks at roughly 3.6 times per
 *              _microsecond_, and its clock continues through Cx state
 *              transitions (unlike many CPU timestamp counters) -- making it
 *              a versatile and accurate timer.
 *
 *              Note that this function accommodates only a single timer
 *              rollover. Thus for 24-bit timers, this function should only
 *              be used for calculating durations less than ~4.6 seconds
 *              (~20 minutes for 32-bit timers) -- calculations below:
 *
 *              2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
 *              2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
 *
 ******************************************************************************/
acpi_status
acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
{
	acpi_status status;
	u32 delta_ticks;
	u64 quotient;

	ACPI_FUNCTION_TRACE(acpi_get_timer_duration);

	if (!time_elapsed) {
		return_ACPI_STATUS(AE_BAD_PARAMETER);
	}

	/* ACPI 5.0A: PM Timer is optional */

	if (!acpi_gbl_FADT.xpm_timer_block.address) {
		return_ACPI_STATUS(AE_SUPPORT);
	}

	/*
	 * Compute Tick Delta:
	 * Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
	 */
	if (start_ticks < end_ticks) {
		delta_ticks = end_ticks - start_ticks;
	} else if (start_ticks > end_ticks) {
		if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {

			/* 24-bit Timer */

			delta_ticks =
			    (((0x00FFFFFF - start_ticks) +
			      end_ticks) & 0x00FFFFFF);
		} else {
			/* 32-bit Timer */

			delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
		}
	} else {		/* start_ticks == end_ticks */

		*time_elapsed = 0;
		return_ACPI_STATUS(AE_OK);
	}

	/*
	 * Compute Duration (Requires a 64-bit multiply and divide):
	 *
	 * time_elapsed (microseconds) =
	 *  (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
	 */
	status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC,
				      ACPI_PM_TIMER_FREQUENCY, &quotient, NULL);

	*time_elapsed = (u32) quotient;
	return_ACPI_STATUS(status);
}

ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)
#endif				/* !ACPI_REDUCED_HARDWARE */
Commit	Line	Data
1da177e4 LT	1	/******************************************************************************
	2	*
	3	* Name: hwtimer.c - ACPI Power Management Timer Interface
	4	*
	5	*****************************************************************************/
	6
	7	/*
25f044e6	8	* Copyright (C) 2000 - 2013, Intel Corp.
1da177e4 LT	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
214f2c90	44	#include <linux/export.h>
1da177e4	45	#include <acpi/acpi.h>
e2f7a777	46	#include "accommon.h"
1da177e4 LT	47
1da177e4 LT	48	#define _COMPONENT ACPI_HARDWARE
4be44fcd	49	ACPI_MODULE_NAME("hwtimer")
1da177e4	50
33620c54	51	#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
1da177e4 LT	52	/******************************************************************************
	53	*
	54	* FUNCTION: acpi_get_timer_resolution
	55	*
ba494bee	56	* PARAMETERS: resolution - Where the resolution is returned
1da177e4 LT	57	*
	58	* RETURN: Status and timer resolution
	59	*
	60	* DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
	61	*
	62	******************************************************************************/
4be44fcd	63	acpi_status acpi_get_timer_resolution(u32 * resolution)
1da177e4	64	{
b229cf92	65	ACPI_FUNCTION_TRACE(acpi_get_timer_resolution);
1da177e4 LT	66
1da177e4 LT	67	if (!resolution) {
4be44fcd	68	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	69	}
1da177e4 LT	70
f3d2e786	71	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
1da177e4	72	*resolution = 24;
4be44fcd	73	} else {
1da177e4 LT	74	*resolution = 32;
	75	}
	76
4be44fcd	77	return_ACPI_STATUS(AE_OK);
1da177e4 LT	78	}
1da177e4 LT	79
8313524a BM	80	ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution)
8313524a BM	81
1da177e4 LT	82	/******************************************************************************
	83	*
	84	* FUNCTION: acpi_get_timer
	85	*
ba494bee	86	* PARAMETERS: ticks - Where the timer value is returned
1da177e4	87	*
44f6c012	88	* RETURN: Status and current timer value (ticks)
1da177e4 LT	89	*
	90	* DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
	91	*
	92	******************************************************************************/
4be44fcd	93	acpi_status acpi_get_timer(u32 * ticks)
1da177e4	94	{
4be44fcd	95	acpi_status status;
1da177e4	96
b229cf92	97	ACPI_FUNCTION_TRACE(acpi_get_timer);
1da177e4 LT	98
1da177e4 LT	99	if (!ticks) {
4be44fcd	100	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	101	}
1da177e4 LT	102
1d82980c BM	103	/* ACPI 5.0A: PM Timer is optional */
	104
	105	if (!acpi_gbl_FADT.xpm_timer_block.address) {
	106	return_ACPI_STATUS(AE_SUPPORT);
	107	}
1da177e4	108
1d82980c	109	status = acpi_hw_read(ticks, &acpi_gbl_FADT.xpm_timer_block);
4be44fcd	110	return_ACPI_STATUS(status);
1da177e4	111	}
1da177e4	112
8313524a	113	ACPI_EXPORT_SYMBOL(acpi_get_timer)
1da177e4 LT	114
	115	/******************************************************************************
	116	*
	117	* FUNCTION: acpi_get_timer_duration
	118	*
	119	* PARAMETERS: start_ticks - Starting timestamp
	120	* end_ticks - End timestamp
	121	* time_elapsed - Where the elapsed time is returned
	122	*
	123	* RETURN: Status and time_elapsed
	124	*
	125	* DESCRIPTION: Computes the time elapsed (in microseconds) between two
	126	* PM Timer time stamps, taking into account the possibility of
	127	* rollovers, the timer resolution, and timer frequency.
	128	*
	129	* The PM Timer's clock ticks at roughly 3.6 times per
	130	* _microsecond_, and its clock continues through Cx state
	131	* transitions (unlike many CPU timestamp counters) -- making it
	132	* a versatile and accurate timer.
	133	*
	134	* Note that this function accommodates only a single timer
73a3090a	135	* rollover. Thus for 24-bit timers, this function should only
1da177e4 LT	136	* be used for calculating durations less than ~4.6 seconds
	137	* (~20 minutes for 32-bit timers) -- calculations below:
	138	*
	139	* 2**24 Ticks / 3,600,000 Ticks/Sec = 4.66 sec
	140	* 2**32 Ticks / 3,600,000 Ticks/Sec = 1193 sec or 19.88 minutes
	141	*
	142	******************************************************************************/
1da177e4	143	acpi_status
4be44fcd	144	acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
1da177e4	145	{
4be44fcd LB	146	acpi_status status;
4be44fcd LB	147	u32 delta_ticks;
5df7e6cb	148	u64 quotient;
1da177e4	149
b229cf92	150	ACPI_FUNCTION_TRACE(acpi_get_timer_duration);
1da177e4 LT	151
1da177e4 LT	152	if (!time_elapsed) {
4be44fcd	153	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	154	}
1da177e4 LT	155
1d82980c BM	156	/* ACPI 5.0A: PM Timer is optional */
	157
	158	if (!acpi_gbl_FADT.xpm_timer_block.address) {
	159	return_ACPI_STATUS(AE_SUPPORT);
	160	}
	161
1da177e4 LT	162	/*
	163	* Compute Tick Delta:
	164	* Handle (max one) timer rollovers on 24-bit versus 32-bit timers.
	165	*/
	166	if (start_ticks < end_ticks) {
	167	delta_ticks = end_ticks - start_ticks;
4be44fcd	168	} else if (start_ticks > end_ticks) {
f3d2e786	169	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
52fc0b02	170
1da177e4 LT	171	/* 24-bit Timer */
1da177e4 LT	172
4be44fcd LB	173	delta_ticks =
	174	(((0x00FFFFFF - start_ticks) +
	175	end_ticks) & 0x00FFFFFF);
	176	} else {
1da177e4 LT	177	/* 32-bit Timer */
	178
	179	delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
	180	}
4be44fcd LB	181	} else { /* start_ticks == end_ticks */
4be44fcd LB	182
1da177e4	183	*time_elapsed = 0;
4be44fcd	184	return_ACPI_STATUS(AE_OK);
1da177e4 LT	185	}
	186
	187	/*
	188	* Compute Duration (Requires a 64-bit multiply and divide):
	189	*
c41679a4 BM	190	* time_elapsed (microseconds) =
c41679a4 BM	191	* (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
1da177e4	192	*/
c41679a4 BM	193	status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC,
c41679a4 BM	194	ACPI_PM_TIMER_FREQUENCY, &quotient, NULL);
1da177e4 LT	195
1da177e4 LT	196	*time_elapsed = (u32) quotient;
4be44fcd	197	return_ACPI_STATUS(status);
1da177e4	198	}
44f6c012	199
8313524a	200	ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)
33620c54	201	#endif /* !ACPI_REDUCED_HARDWARE */