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acpi_timer.c revision 1.19
      1  1.19    jruoho /* $NetBSD: acpi_timer.c,v 1.19 2011/01/02 05:48:55 jruoho Exp $ */
      2  1.16    jruoho 
      3  1.16    jruoho /*-
      4  1.16    jruoho  * Copyright (c) 2006 Matthias Drochner <drochner (at) NetBSD.org>
      5  1.16    jruoho  * All rights reserved.
      6  1.16    jruoho  *
      7  1.16    jruoho  * Redistribution and use in source and binary forms, with or without
      8  1.16    jruoho  * modification, are permitted provided that the following conditions
      9  1.16    jruoho  * are met:
     10  1.16    jruoho  * 1. Redistributions of source code must retain the above copyright
     11  1.16    jruoho  *    notice, this list of conditions and the following disclaimer.
     12  1.16    jruoho  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.16    jruoho  *    notice, this list of conditions and the following disclaimer in the
     14  1.16    jruoho  *    documentation and/or other materials provided with the distribution.
     15  1.16    jruoho  *
     16  1.16    jruoho  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  1.16    jruoho  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  1.16    jruoho  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  1.16    jruoho  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  1.16    jruoho  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  1.16    jruoho  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  1.16    jruoho  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  1.16    jruoho  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  1.16    jruoho  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  1.16    jruoho  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  1.16    jruoho  * POSSIBILITY OF SUCH DAMAGE.
     27  1.16    jruoho  */
     28   1.4   xtraeme 
     29   1.4   xtraeme #include <sys/cdefs.h>
     30  1.19    jruoho __KERNEL_RCSID(0, "$NetBSD: acpi_timer.c,v 1.19 2011/01/02 05:48:55 jruoho Exp $");
     31   1.1  drochner 
     32   1.1  drochner #include <sys/types.h>
     33   1.1  drochner #include <sys/systm.h>
     34   1.1  drochner #include <sys/time.h>
     35   1.1  drochner #include <sys/timetc.h>
     36  1.15    jruoho 
     37  1.15    jruoho #include <dev/acpi/acpivar.h>
     38  1.10     joerg #include <dev/acpi/acpi_timer.h>
     39  1.15    jruoho 
     40  1.12  jmcneill #include <machine/acpi_machdep.h>
     41   1.1  drochner 
     42  1.17    jruoho static int	acpitimer_test(void);
     43   1.1  drochner 
     44   1.1  drochner static struct timecounter acpi_timecounter = {
     45   1.2  drochner 	acpitimer_read_safe,
     46   1.1  drochner 	0,
     47   1.1  drochner 	0x00ffffff,
     48   1.1  drochner 	PM_TIMER_FREQUENCY,
     49   1.2  drochner 	"ACPI-Safe",
     50   1.6  christos 	900,
     51   1.6  christos 	NULL,
     52   1.6  christos 	NULL,
     53   1.1  drochner };
     54   1.1  drochner 
     55   1.1  drochner int
     56  1.17    jruoho acpitimer_init(struct acpi_softc *sc)
     57   1.1  drochner {
     58  1.19    jruoho 	const uint32_t flags = AcpiGbl_FADT.Flags;
     59  1.19    jruoho 	ACPI_STATUS rv;
     60   1.1  drochner 	uint32_t bits;
     61   1.2  drochner 	int i, j;
     62   1.1  drochner 
     63  1.19    jruoho 	rv = AcpiGetTimerResolution(&bits);
     64  1.17    jruoho 
     65  1.19    jruoho 	if (ACPI_FAILURE(rv))
     66  1.18    jruoho 		return -1;
     67   1.1  drochner 
     68   1.1  drochner 	if (bits == 32)
     69   1.1  drochner 		acpi_timecounter.tc_counter_mask = 0xffffffff;
     70   1.2  drochner 
     71  1.17    jruoho 	for (i = j = 0; i < 10; i++)
     72   1.2  drochner 		j += acpitimer_test();
     73   1.3   xtraeme 
     74   1.2  drochner 	if (j >= 10) {
     75   1.2  drochner 		acpi_timecounter.tc_name = "ACPI-Fast";
     76   1.2  drochner 		acpi_timecounter.tc_get_timecount = acpitimer_read_fast;
     77   1.2  drochner 		acpi_timecounter.tc_quality = 1000;
     78   1.2  drochner 	}
     79  1.17    jruoho 
     80   1.1  drochner 	tc_init(&acpi_timecounter);
     81   1.1  drochner 
     82  1.19    jruoho 	aprint_debug_dev(sc->sc_dev, "%s %d-bit timer\n",
     83  1.19    jruoho 	    acpi_timecounter.tc_name, bits);
     84  1.19    jruoho 
     85  1.19    jruoho 	if ((flags & ACPI_FADT_PLATFORM_CLOCK) != 0)
     86  1.19    jruoho 		aprint_debug_dev(sc->sc_dev,
     87  1.19    jruoho 		    "warning: timer may be unreliable\n");
     88  1.17    jruoho 
     89  1.17    jruoho 	return 0;
     90   1.2  drochner }
     91   1.1  drochner 
     92  1.14    dyoung int
     93  1.14    dyoung acpitimer_detach(void)
     94  1.14    dyoung {
     95  1.17    jruoho 
     96  1.14    dyoung 	return tc_detach(&acpi_timecounter);
     97  1.14    dyoung }
     98  1.14    dyoung 
     99  1.17    jruoho u_int
    100   1.8  christos acpitimer_read_fast(struct timecounter *tc)
    101   1.2  drochner {
    102   1.2  drochner 	uint32_t t;
    103   1.2  drochner 
    104  1.17    jruoho 	(void)AcpiGetTimer(&t);
    105  1.17    jruoho 
    106  1.17    jruoho 	return t;
    107   1.1  drochner }
    108   1.1  drochner 
    109   1.1  drochner /*
    110  1.18    jruoho  * Some chipsets (PIIX4 variants) do not latch correctly;
    111  1.18    jruoho  * there is a chance that a transition is hit.
    112   1.1  drochner  */
    113  1.17    jruoho u_int
    114   1.8  christos acpitimer_read_safe(struct timecounter *tc)
    115   1.1  drochner {
    116   1.1  drochner 	uint32_t t1, t2, t3;
    117   1.1  drochner 
    118  1.17    jruoho 	(void)AcpiGetTimer(&t2);
    119  1.17    jruoho 	(void)AcpiGetTimer(&t3);
    120  1.17    jruoho 
    121   1.1  drochner 	do {
    122   1.1  drochner 		t1 = t2;
    123   1.1  drochner 		t2 = t3;
    124  1.17    jruoho 
    125  1.17    jruoho 		(void)AcpiGetTimer(&t3);
    126  1.17    jruoho 
    127   1.1  drochner 	} while ((t1 > t2) || (t2 > t3));
    128  1.17    jruoho 
    129  1.17    jruoho 	return t2;
    130   1.1  drochner }
    131   1.1  drochner 
    132  1.18    jruoho uint32_t
    133   1.2  drochner acpitimer_delta(uint32_t end, uint32_t start)
    134   1.2  drochner {
    135  1.17    jruoho 	const u_int mask = acpi_timecounter.tc_counter_mask;
    136   1.2  drochner 	uint32_t delta;
    137   1.2  drochner 
    138   1.2  drochner 	if (end >= start)
    139   1.2  drochner 		delta = end - start;
    140   1.2  drochner 	else
    141   1.2  drochner 		delta = ((mask - start) + end + 1) & mask;
    142   1.2  drochner 
    143  1.17    jruoho 	return delta;
    144   1.2  drochner }
    145   1.2  drochner 
    146   1.2  drochner #define N 2000
    147  1.17    jruoho 
    148   1.2  drochner static int
    149  1.13    cegger acpitimer_test(void)
    150   1.2  drochner {
    151   1.2  drochner 	uint32_t last, this, delta;
    152   1.2  drochner 	int minl, maxl, n;
    153   1.2  drochner 
    154   1.2  drochner 	minl = 10000000;
    155   1.2  drochner 	maxl = 0;
    156   1.2  drochner 
    157  1.12  jmcneill 	acpi_md_OsDisableInterrupt();
    158  1.17    jruoho 
    159  1.17    jruoho 	(void)AcpiGetTimer(&last);
    160  1.17    jruoho 
    161   1.2  drochner 	for (n = 0; n < N; n++) {
    162  1.17    jruoho 
    163  1.17    jruoho 		(void)AcpiGetTimer(&this);
    164  1.17    jruoho 
    165   1.2  drochner 		delta = acpitimer_delta(this, last);
    166  1.17    jruoho 
    167   1.2  drochner 		if (delta > maxl)
    168   1.2  drochner 			maxl = delta;
    169   1.2  drochner 		else if (delta < minl)
    170   1.2  drochner 			minl = delta;
    171  1.17    jruoho 
    172   1.2  drochner 		last = this;
    173   1.2  drochner 	}
    174  1.17    jruoho 
    175  1.12  jmcneill 	acpi_md_OsEnableInterrupt();
    176   1.2  drochner 
    177   1.2  drochner 	if (maxl - minl > 2 )
    178   1.2  drochner 		n = 0;
    179   1.2  drochner 	else if (minl < 0 || maxl == 0)
    180   1.2  drochner 		n = 0;
    181   1.2  drochner 	else
    182   1.2  drochner 		n = 1;
    183   1.2  drochner 
    184  1.17    jruoho 	return n;
    185   1.2  drochner }
    186