[mirror_ubuntu-artful-kernel.git] / drivers / acpi / acpica / hwtimer.c

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

/*
 * Copyright (C) 2000 - 2017, 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.
 */

#define EXPORT_ACPI_INTERFACES

#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	/*
7735ca0e	8	* Copyright (C) 2000 - 2017, 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
839e928f LZ	44	#define EXPORT_ACPI_INTERFACES
839e928f LZ	45
1da177e4	46	#include <acpi/acpi.h>
e2f7a777	47	#include "accommon.h"
1da177e4 LT	48
1da177e4 LT	49	#define _COMPONENT ACPI_HARDWARE
4be44fcd	50	ACPI_MODULE_NAME("hwtimer")
1da177e4	51
33620c54	52	#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
1da177e4 LT	53	/******************************************************************************
	54	*
	55	* FUNCTION: acpi_get_timer_resolution
	56	*
ba494bee	57	* PARAMETERS: resolution - Where the resolution is returned
1da177e4 LT	58	*
	59	* RETURN: Status and timer resolution
	60	*
	61	* DESCRIPTION: Obtains resolution of the ACPI PM Timer (24 or 32 bits).
	62	*
	63	******************************************************************************/
4be44fcd	64	acpi_status acpi_get_timer_resolution(u32 * resolution)
1da177e4	65	{
b229cf92	66	ACPI_FUNCTION_TRACE(acpi_get_timer_resolution);
1da177e4 LT	67
1da177e4 LT	68	if (!resolution) {
4be44fcd	69	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	70	}
1da177e4 LT	71
f3d2e786	72	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
1da177e4	73	*resolution = 24;
4be44fcd	74	} else {
1da177e4 LT	75	*resolution = 32;
	76	}
	77
4be44fcd	78	return_ACPI_STATUS(AE_OK);
1da177e4 LT	79	}
1da177e4 LT	80
8313524a BM	81	ACPI_EXPORT_SYMBOL(acpi_get_timer_resolution)
8313524a BM	82
1da177e4 LT	83	/******************************************************************************
	84	*
	85	* FUNCTION: acpi_get_timer
	86	*
ba494bee	87	* PARAMETERS: ticks - Where the timer value is returned
1da177e4	88	*
44f6c012	89	* RETURN: Status and current timer value (ticks)
1da177e4 LT	90	*
	91	* DESCRIPTION: Obtains current value of ACPI PM Timer (in ticks).
	92	*
	93	******************************************************************************/
4be44fcd	94	acpi_status acpi_get_timer(u32 * ticks)
1da177e4	95	{
4be44fcd	96	acpi_status status;
1da177e4	97
b229cf92	98	ACPI_FUNCTION_TRACE(acpi_get_timer);
1da177e4 LT	99
1da177e4 LT	100	if (!ticks) {
4be44fcd	101	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	102	}
1da177e4 LT	103
1d82980c BM	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	}
1da177e4	109
1d82980c	110	status = acpi_hw_read(ticks, &acpi_gbl_FADT.xpm_timer_block);
4be44fcd	111	return_ACPI_STATUS(status);
1da177e4	112	}
1da177e4	113
8313524a	114	ACPI_EXPORT_SYMBOL(acpi_get_timer)
1da177e4 LT	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
73a3090a	136	* rollover. Thus for 24-bit timers, this function should only
1da177e4 LT	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	******************************************************************************/
1da177e4	144	acpi_status
4be44fcd	145	acpi_get_timer_duration(u32 start_ticks, u32 end_ticks, u32 * time_elapsed)
1da177e4	146	{
4be44fcd LB	147	acpi_status status;
4be44fcd LB	148	u32 delta_ticks;
5df7e6cb	149	u64 quotient;
1da177e4	150
b229cf92	151	ACPI_FUNCTION_TRACE(acpi_get_timer_duration);
1da177e4 LT	152
1da177e4 LT	153	if (!time_elapsed) {
4be44fcd	154	return_ACPI_STATUS(AE_BAD_PARAMETER);
1da177e4 LT	155	}
1da177e4 LT	156
1d82980c BM	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
1da177e4 LT	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;
4be44fcd	169	} else if (start_ticks > end_ticks) {
f3d2e786	170	if ((acpi_gbl_FADT.flags & ACPI_FADT_32BIT_TIMER) == 0) {
52fc0b02	171
1da177e4 LT	172	/* 24-bit Timer */
1da177e4 LT	173
4be44fcd LB	174	delta_ticks =
	175	(((0x00FFFFFF - start_ticks) +
	176	end_ticks) & 0x00FFFFFF);
	177	} else {
1da177e4 LT	178	/* 32-bit Timer */
	179
	180	delta_ticks = (0xFFFFFFFF - start_ticks) + end_ticks;
	181	}
4be44fcd LB	182	} else { /* start_ticks == end_ticks */
4be44fcd LB	183
1da177e4	184	*time_elapsed = 0;
4be44fcd	185	return_ACPI_STATUS(AE_OK);
1da177e4 LT	186	}
	187
	188	/*
	189	* Compute Duration (Requires a 64-bit multiply and divide):
	190	*
c41679a4 BM	191	* time_elapsed (microseconds) =
c41679a4 BM	192	* (delta_ticks * ACPI_USEC_PER_SEC) / ACPI_PM_TIMER_FREQUENCY;
1da177e4	193	*/
c41679a4 BM	194	status = acpi_ut_short_divide(((u64)delta_ticks) * ACPI_USEC_PER_SEC,
c41679a4 BM	195	ACPI_PM_TIMER_FREQUENCY, &quotient, NULL);
1da177e4 LT	196
1da177e4 LT	197	*time_elapsed = (u32) quotient;
4be44fcd	198	return_ACPI_STATUS(status);
1da177e4	199	}
44f6c012	200
8313524a	201	ACPI_EXPORT_SYMBOL(acpi_get_timer_duration)
33620c54	202	#endif /* !ACPI_REDUCED_HARDWARE */