181 lines
3.7 KiB
C
181 lines
3.7 KiB
C
/* $NetBSD: acpi_timer.c,v 1.22 2013/12/27 18:51:44 christos Exp $ */
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/*-
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* Copyright (c) 2006 Matthias Drochner <drochner@NetBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: acpi_timer.c,v 1.22 2013/12/27 18:51:44 christos Exp $");
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#include <sys/types.h>
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#include <sys/systm.h>
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#include <sys/time.h>
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#include <sys/timetc.h>
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#include <dev/acpi/acpivar.h>
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#include <dev/acpi/acpi_timer.h>
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#include <machine/acpi_machdep.h>
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static int acpitimer_test(void);
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static struct timecounter acpi_timecounter = {
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acpitimer_read_safe,
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0,
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0x00ffffff,
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ACPI_PM_TIMER_FREQUENCY,
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"ACPI-Safe",
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900,
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NULL,
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NULL,
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};
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int
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acpitimer_init(struct acpi_softc *sc)
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{
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ACPI_STATUS rv;
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uint32_t bits;
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int i, j;
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rv = AcpiGetTimerResolution(&bits);
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if (ACPI_FAILURE(rv))
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return -1;
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if (bits == 32)
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acpi_timecounter.tc_counter_mask = 0xffffffff;
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for (i = j = 0; i < 10; i++)
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j += acpitimer_test();
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if (j >= 10) {
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acpi_timecounter.tc_name = "ACPI-Fast";
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acpi_timecounter.tc_get_timecount = acpitimer_read_fast;
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acpi_timecounter.tc_quality = 1000;
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}
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tc_init(&acpi_timecounter);
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aprint_debug_dev(sc->sc_dev, "%s %d-bit timer\n",
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acpi_timecounter.tc_name, bits);
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return 0;
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}
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int
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acpitimer_detach(void)
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{
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return tc_detach(&acpi_timecounter);
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}
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u_int
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acpitimer_read_fast(struct timecounter *tc)
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{
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uint32_t t;
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(void)AcpiGetTimer(&t);
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return t;
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}
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/*
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* Some chipsets (PIIX4 variants) do not latch correctly;
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* there is a chance that a transition is hit.
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*/
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u_int
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acpitimer_read_safe(struct timecounter *tc)
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{
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uint32_t t1, t2, t3;
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(void)AcpiGetTimer(&t2);
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(void)AcpiGetTimer(&t3);
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do {
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t1 = t2;
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t2 = t3;
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(void)AcpiGetTimer(&t3);
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} while ((t1 > t2) || (t2 > t3));
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return t2;
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}
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uint32_t
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acpitimer_delta(uint32_t end, uint32_t start)
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{
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const u_int mask = acpi_timecounter.tc_counter_mask;
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uint32_t delta;
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if (end >= start)
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delta = end - start;
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else
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delta = ((mask - start) + end + 1) & mask;
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return delta;
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}
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#define N 2000
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static int
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acpitimer_test(void)
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{
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uint32_t last, this, delta;
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int minl, maxl, n;
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minl = 10000000;
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maxl = 0;
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acpi_md_OsDisableInterrupt();
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(void)AcpiGetTimer(&last);
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for (n = 0; n < N; n++) {
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(void)AcpiGetTimer(&this);
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delta = acpitimer_delta(this, last);
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if (delta > maxl)
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maxl = delta;
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else if (delta < minl)
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minl = delta;
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last = this;
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}
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acpi_md_OsEnableInterrupt();
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if (maxl - minl > 2 )
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n = 0;
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else if (minl < 0 || maxl == 0)
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n = 0;
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else
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n = 1;
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return n;
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}
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