787fa5b805
This code is based on the mp_clock code by phk. It attempts to detect the PIIX4 (see comments for details) and use a workaround for its problems. This code is experimental, and could use some testing and review by a timekeeping enthusiast.
309 lines
8.7 KiB
C
309 lines
8.7 KiB
C
/*-
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* Copyright (c) 2000, 2001 Michael Smith
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* Copyright (c) 2000 BSDi
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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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*/
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#include "opt_acpi.h"
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#include <sys/param.h>
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#include <sys/bus.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/timetc.h>
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#include <machine/bus_pio.h>
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#include <machine/bus.h>
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#include <machine/resource.h>
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#include <sys/rman.h>
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#include "acpi.h"
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#include <acpica/acpivar.h>
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#include <pci/pcivar.h>
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/*
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* A timecounter based on the free-running ACPI timer.
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*
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* Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
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*/
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/*
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* Hooks for the ACPI CA debugging infrastructure
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*/
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#define _COMPONENT ACPI_SYSTEM
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MODULE_NAME("TIMER")
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static device_t acpi_timer_dev;
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struct resource *acpi_timer_reg;
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#define TIMER_READ bus_space_read_4(rman_get_bustag(acpi_timer_reg), \
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rman_get_bushandle(acpi_timer_reg), \
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0)
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static int acpi_timer_flags;
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/*
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* ] 20. ACPI Timer Errata
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* ]
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* ] Problem: The power management timer may return improper result when
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* ] read. Although the timer value settles properly after incrementing,
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* ] while incrementing there is a 3nS window every 69.8nS where the
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* ] timer value is indeterminate (a 4.2% chance that the data will be
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* ] incorrect when read). As a result, the ACPI free running count up
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* ] timer specification is violated due to erroneous reads. Implication:
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* ] System hangs due to the "inaccuracy" of the timer when used by
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* ] software for time critical events and delays.
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* ]
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* ] Workaround: Read the register twice and compare.
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* ] Status: This will not be fixed in the PIIX4 or PIIX4E.
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*
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* The counter is in other words not latched to the PCI bus clock when
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* read. Notice the workaround isn't: We need to read until we have
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* three monotonic samples and then use the middle one, otherwise we are
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* not protected against the fact that the bits can be wrong in two
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* directions. If we only cared about monosity two reads would be enough.
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*/
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#define TFLAG_NEED_PIIX_WAR (1 << 0)
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static u_int acpi_timer_frequency = 14318182/4;
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static void acpi_timer_identify(driver_t *driver, device_t parent);
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static int acpi_timer_probe(device_t dev);
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static int acpi_timer_attach(device_t dev);
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static int acpi_timer_pci_probe(device_t dev);
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static unsigned acpi_timer_get_timecount(struct timecounter *tc);
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static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
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static void acpi_timer_test(void);
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/*
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* Driver hung off ACPI.
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*/
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static device_method_t acpi_timer_methods[] = {
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DEVMETHOD(device_identify, acpi_timer_identify),
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DEVMETHOD(device_probe, acpi_timer_probe),
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DEVMETHOD(device_attach, acpi_timer_attach),
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{0, 0}
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};
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static driver_t acpi_timer_driver = {
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"acpi_timer",
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acpi_timer_methods,
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0,
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};
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devclass_t acpi_timer_devclass;
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DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
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/*
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* Chipset workaround driver hung off PCI.
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*/
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static device_method_t acpi_timer_pci_methods[] = {
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DEVMETHOD(device_probe, acpi_timer_pci_probe),
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{0, 0}
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};
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static driver_t acpi_timer_pci_driver = {
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"acpi_timer_pci",
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acpi_timer_pci_methods,
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0,
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};
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devclass_t acpi_timer_pci_devclass;
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DRIVER_MODULE(acpi_timer_pci, pci, acpi_timer_pci_driver, acpi_timer_pci_devclass, 0, 0);
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/*
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* Timecounter.
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*/
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static struct timecounter acpi_timer_timecounter = {
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acpi_timer_get_timecount,
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0,
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0xffffff,
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0,
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"ACPI"
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};
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SYSCTL_OPAQUE(_debug, OID_AUTO, acpi_timecounter, CTLFLAG_RD,
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&acpi_timer_timecounter, sizeof(acpi_timer_timecounter), "S,timecounter", "");
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/*
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* Locate the ACPI timer using the FADT, set up and allocate the I/O resources
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* we will be using.
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*/
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static void
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acpi_timer_identify(driver_t *driver, device_t parent)
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{
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device_t dev;
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char desc[40];
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int rid;
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FUNCTION_TRACE(__func__);
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if (acpi_disabled("timer"))
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return_VOID;
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if (AcpiGbl_FADT == NULL)
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return_VOID;
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if ((dev = BUS_ADD_CHILD(parent, 0, "acpi_timer", 0)) == NULL) {
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device_printf(parent, "could not add acpi_timer0\n");
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return_VOID;
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}
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acpi_timer_dev = dev;
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rid = 0;
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bus_set_resource(dev, SYS_RES_IOPORT, rid, AcpiGbl_FADT->V1_PmTmrBlk, sizeof(u_int32_t));
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if ((acpi_timer_reg = bus_alloc_resource(dev, SYS_RES_IOPORT, &rid, 0, ~0, 1, RF_ACTIVE)) == NULL) {
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device_printf(dev, "couldn't allocate I/O resource (port 0x%x)\n", AcpiGbl_FADT->V1_PmTmrBlk);
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return_VOID;
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}
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if (getenv("debug.acpi.timer_test") != NULL)
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acpi_timer_test();
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acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
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tc_init(&acpi_timer_timecounter);
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sprintf(desc, "%d-bit timer at 3.579545MHz", AcpiGbl_FADT->TmrValExt ? 32 : 24);
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device_set_desc_copy(dev, desc);
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return_VOID;
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}
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static int
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acpi_timer_probe(device_t dev)
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{
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if (dev == acpi_timer_dev)
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return(0);
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return(ENXIO);
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}
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static int
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acpi_timer_attach(device_t dev)
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{
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return(0);
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}
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/*
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* Look at PCI devices as they go past, and if we detect a PIIX4, set
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* the PIIX_WAR flag.
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*
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* XXX do we know that other timecounters work? Interesting question.
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*/
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static int
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acpi_timer_pci_probe(device_t dev)
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{
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if ((pci_get_vendor(dev) == 0x8086) &&
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(pci_get_device(dev) == 0x7113)) {
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acpi_timer_flags |= TFLAG_NEED_PIIX_WAR;
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device_printf(acpi_timer_dev, "enabling PIIX4 timer workaround\n");
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}
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return(ENXIO); /* we never match anything */
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}
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/*
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* Fetch current time value from hardware.
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*
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* XXX This is currently written to be "correct", not
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* "fast". Optimisation is strongly indicated.
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*/
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static unsigned
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acpi_timer_get_timecount(struct timecounter *tc)
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{
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unsigned u1, u2, u3;
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if (acpi_timer_flags & TFLAG_NEED_PIIX_WAR) {
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u2 = TIMER_READ;
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u3 = TIMER_READ;
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do {
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u1 = u2;
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u2 = u3;
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u3 = TIMER_READ;
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} while (u1 > u2 || u2 > u3);
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return (u2);
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} else {
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return(TIMER_READ);
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}
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}
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/*
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* Timecounter freqency adjustment interface.
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*/
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static int
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acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
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{
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int error;
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u_int freq;
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if (acpi_timer_timecounter.tc_frequency == 0)
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return (EOPNOTSUPP);
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freq = acpi_timer_frequency;
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error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
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if (error == 0 && req->newptr != NULL) {
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acpi_timer_frequency = freq;
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acpi_timer_timecounter.tc_frequency = acpi_timer_frequency;
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tc_update(&acpi_timer_timecounter);
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}
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return (error);
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}
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SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
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0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
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/*
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* Test harness for verifying ACPI timer behaviour.
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* Boot with debug.acpi.timer_test set to invoke this.
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*/
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static void
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acpi_timer_test(void)
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{
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u_int32_t u1, u2, u3;
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u1 = TIMER_READ;
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u2 = TIMER_READ;
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u3 = TIMER_READ;
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device_printf(acpi_timer_dev, "timer test in progress, reboot to quit.\n");
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for (;;) {
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/*
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* The failure case is where u3 > u1, but u2 does not fall between the two,
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* ie. it contains garbage.
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*/
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if (u3 > u1) {
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if ((u2 < u1) || (u2 > u3))
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device_printf(acpi_timer_dev, "timer is not monotonic: 0x%08x,0x%08x,0x%08x\n",
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u1, u2, u3);
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}
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u1 = u2;
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u2 = u3;
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u3 = TIMER_READ;
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}
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}
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