[dragonfly.git] / sys / dev / acpica5 / acpi_timer.c

/*-
 * Copyright (c) 2000, 2001 Michael Smith
 * Copyright (c) 2000 BSDi
 * 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.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, 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 DAMAGE.
 *
 * $FreeBSD: src/sys/dev/acpica/acpi_timer.c,v 1.35 2004/07/22 05:42:14 njl Exp $
 * $DragonFly: src/sys/dev/acpica5/acpi_timer.c,v 1.13 2007/10/09 09:46:56 y0netan1 Exp $
 */
#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/sysctl.h>
#include <sys/systimer.h>
#include <sys/rman.h>

#include <machine/lock.h>
#include <bus/pci/pcivar.h>

#include "acpi.h"
#include "accommon.h"
#include "acpivar.h"

/*
 * A timecounter based on the free-running ACPI timer.
 *
 * Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
 */

/* Hooks for the ACPI CA debugging infrastructure */
#define _COMPONENT	ACPI_TIMER
ACPI_MODULE_NAME("TIMER")

static device_t			acpi_timer_dev;
static struct resource		*acpi_timer_reg;
static bus_space_handle_t	acpi_timer_bsh;
static bus_space_tag_t		acpi_timer_bst;
static sysclock_t		acpi_counter_mask;
static sysclock_t		acpi_last_counter;

#define ACPI_TIMER_FREQ		(14318182 / 4)

static sysclock_t acpi_timer_get_timecount(void);
static sysclock_t acpi_timer_get_timecount24(void);
static sysclock_t acpi_timer_get_timecount_safe(void);
static void acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock);

static struct cputimer acpi_cputimer = {
	SLIST_ENTRY_INITIALIZER,
	"ACPI",
	CPUTIMER_PRI_ACPI,
	CPUTIMER_ACPI,
	acpi_timer_get_timecount_safe,
	cputimer_default_fromhz,
	cputimer_default_fromus,
	acpi_timer_construct,
	cputimer_default_destruct,
	ACPI_TIMER_FREQ,
	0, 0, 0
};

static int	acpi_timer_identify(driver_t *driver, device_t parent);
static int	acpi_timer_probe(device_t dev);
static int	acpi_timer_attach(device_t dev);
static int	acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);

static u_int	acpi_timer_read(void);
static int	acpi_timer_test(void);

static device_method_t acpi_timer_methods[] = {
    DEVMETHOD(device_identify,	acpi_timer_identify),
    DEVMETHOD(device_probe,	acpi_timer_probe),
    DEVMETHOD(device_attach,	acpi_timer_attach),

    {0, 0}
};

static driver_t acpi_timer_driver = {
    "acpi_timer",
    acpi_timer_methods,
    0,
};

static devclass_t acpi_timer_devclass;
DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);

static u_int
acpi_timer_read(void)
{
    return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
}

/*
 * Locate the ACPI timer using the FADT, set up and allocate the I/O resources
 * we will be using.
 */
static int
acpi_timer_identify(driver_t *driver, device_t parent)
{
    device_t dev;
    u_long rlen, rstart;
    int rid, rtype;

    /*
     * Just try once, do nothing if the 'acpi' bus is rescanned.
     */
    if (device_get_state(parent) == DS_ATTACHED)
	return (0);

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    if (acpi_disabled("timer") || acpi_timer_dev)
	return (ENXIO);

    if ((dev = BUS_ADD_CHILD(parent, parent, 0, "acpi_timer", 0)) == NULL) {
	device_printf(parent, "could not add acpi_timer0\n");
	return (ENXIO);
    }
    acpi_timer_dev = dev;

    rid = 0;
    rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
	SYS_RES_IOPORT : SYS_RES_MEMORY;
    rlen = AcpiGbl_FADT.PmTimerLength;
    rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
    if (bus_set_resource(dev, rtype, rid, rstart, rlen)) {
	device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
	    (rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
	return (ENXIO);
    }
    return (0);
}

static int
acpi_timer_probe(device_t dev)
{
    char desc[40];
    int i, j, rid, rtype;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    if (dev != acpi_timer_dev)
	return (ENXIO);

    rid = 0;
    rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
	SYS_RES_IOPORT : SYS_RES_MEMORY;
    acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
    if (acpi_timer_reg == NULL) {
	device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
	    (rtype == SYS_RES_IOPORT) ? "port" : "mem",
	    (u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
	return (ENXIO);
    }
    acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
    acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
    if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0)
	acpi_counter_mask = 0xffffffff;
    else
	acpi_counter_mask = 0x00ffffff;

    /*
     * If all tests of the counter succeed, use the ACPI-fast method.  If
     * at least one failed, default to using the safe routine, which reads
     * the timer multiple times to get a consistent value before returning.
     */
    j = 0;
    for (i = 0; i < 10; i++)
	j += acpi_timer_test();
    if (j == 10) {
	if (acpi_counter_mask == 0xffffffff) {
	    acpi_cputimer.name = "ACPI-fast";
	    acpi_cputimer.count = acpi_timer_get_timecount;
	} else {
	    acpi_cputimer.name = "ACPI-fast24";
	    acpi_cputimer.count = acpi_timer_get_timecount24;
	}
    } else {
	if (acpi_counter_mask == 0xffffffff)
		acpi_cputimer.name = "ACPI-safe";
	else
		acpi_cputimer.name = "ACPI-safe24";
	acpi_cputimer.count = acpi_timer_get_timecount_safe;
    }

    ksprintf(desc, "%d-bit timer at 3.579545MHz",
	    (AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24);
    device_set_desc_copy(dev, desc);

    cputimer_register(&acpi_cputimer);
    cputimer_select(&acpi_cputimer, 0);
    /* Release the resource, we'll allocate it again during attach. */
    bus_release_resource(dev, rtype, rid, acpi_timer_reg);
    return (0);
}

static int
acpi_timer_attach(device_t dev)
{
    int rid, rtype;

    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);

    rid = 0;
    rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
	SYS_RES_IOPORT : SYS_RES_MEMORY;
    acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
    if (acpi_timer_reg == NULL)
	return (ENXIO);
    acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
    acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
    return (0);
}

/*
 * Construct the timer.  Adjust the base so the system clock does not
 * jump weirdly.
 */
static void
acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock)
{
    timer->base = 0;
    timer->base = oldclock - acpi_timer_get_timecount_safe();
}

/*
 * Fetch current time value from reliable hardware.
 *
 * The cputimer interface requires a 32 bit return value.  If the ACPI timer
 * is only 24 bits then we have to keep track of the upper 8 bits on our
 * own.
 *
 * XXX we could probably get away with using a per-cpu field for this and
 * just use interrupt disablement instead of clock_lock.
 */
static sysclock_t
acpi_timer_get_timecount24(void)
{
    sysclock_t counter;

    clock_lock();
    counter = acpi_timer_read();
    if (counter < acpi_last_counter)
	acpi_cputimer.base += 0x01000000;
    acpi_last_counter = counter;
    counter += acpi_cputimer.base;
    clock_unlock();
    return (counter);
}

static sysclock_t
acpi_timer_get_timecount(void)
{
    return (acpi_timer_read() + acpi_cputimer.base);
}

/*
 * Fetch current time value from hardware that may not correctly
 * latch the counter.  We need to read until we have three monotonic
 * samples and then use the middle one, otherwise we are not protected
 * against the fact that the bits can be wrong in two directions.  If
 * we only cared about monosity, two reads would be enough.
 */
static sysclock_t
acpi_timer_get_timecount_safe(void)
{
    u_int u1, u2, u3;

    if (acpi_counter_mask != 0xffffffff)
	clock_lock();

    u2 = acpi_timer_read();
    u3 = acpi_timer_read();
    do {
	u1 = u2;
	u2 = u3;
	u3 = acpi_timer_read();
    } while (u1 > u2 || u2 > u3);

    if (acpi_counter_mask != 0xffffffff) {
	if (u2 < acpi_last_counter)
	    acpi_cputimer.base += 0x01000000;
	acpi_last_counter = u2;
	clock_unlock();
    }
    return (u2 + acpi_cputimer.base);
}

/*
 * Timecounter freqency adjustment interface.
 */ 
static int
acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
{
    int error;
    u_int freq;
 
    if (acpi_cputimer.freq == 0)
	return (EOPNOTSUPP);
    freq = acpi_cputimer.freq;
    error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
    if (error == 0 && req->newptr != NULL)
	cputimer_set_frequency(&acpi_cputimer, freq);

    return (error);
}
 
SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT | CTLFLAG_RW,
	    0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");

/*
 * Some ACPI timers are known or believed to suffer from implementation
 * problems which can lead to erroneous values being read.  This function
 * tests for consistent results from the timer and returns 1 if it believes
 * the timer is consistent, otherwise it returns 0.
 *
 * It appears the cause is that the counter is not latched to the PCI bus
 * clock when read:
 *
 * ] 20. ACPI Timer Errata
 * ]
 * ]   Problem: The power management timer may return improper result when
 * ]   read. Although the timer value settles properly after incrementing,
 * ]   while incrementing there is a 3nS window every 69.8nS where the
 * ]   timer value is indeterminate (a 4.2% chance that the data will be
 * ]   incorrect when read). As a result, the ACPI free running count up
 * ]   timer specification is violated due to erroneous reads.  Implication:
 * ]   System hangs due to the "inaccuracy" of the timer when used by
 * ]   software for time critical events and delays.
 * ]
 * ] Workaround: Read the register twice and compare.
 * ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
 * ] in the PIIX4M.
 */

static int
acpi_timer_test(void)
{
    uint32_t	last, this;
    int		min, max, n, delta;
    register_t	s;

    min = 10000000;
    max = 0;

    /* Test the timer with interrupts disabled to get accurate results. */
#if defined(__i386__)
    s = read_eflags();
#elif defined(__x86_64__)
    s = read_rflags();
#else
#error "no read_eflags"
#endif
    cpu_disable_intr();
    last = acpi_timer_read();
    for (n = 0; n < 2000; n++) {
	this = acpi_timer_read();
	delta = acpi_TimerDelta(this, last);
	if (delta > max)
	    max = delta;
	else if (delta < min)
	    min = delta;
	last = this;
    }
#if defined(__i386__)
    write_eflags(s);
#elif defined(__x86_64__)
    write_rflags(s);
#else
#error "no read_eflags"
#endif

    if (max - min > 2)
	n = 0;
    else if (min < 0 || max == 0)
	n = 0;
    else
	n = 1;
    if (bootverbose) {
	kprintf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
		n ? "GOOD" : "BAD ",
		min, max, max - min);
    }

    return (n);
}
Commit	Line	Data
5ed44076 MD	1	/*-
	2	* Copyright (c) 2000, 2001 Michael Smith
	3	* Copyright (c) 2000 BSDi
	4	* All rights reserved.
	5	*
	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions and the following disclaimer.
	11	* 2. Redistributions in binary form must reproduce the above copyright
	12	* notice, this list of conditions and the following disclaimer in the
	13	* documentation and/or other materials provided with the distribution.
	14	*
	15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
	16	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	17	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	18	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
	19	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	20	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	21	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	22	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	23	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	24	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	25	* SUCH DAMAGE.
	26	*
3e5760cd YT	27	* $FreeBSD: src/sys/dev/acpica/acpi_timer.c,v 1.35 2004/07/22 05:42:14 njl Exp $
3e5760cd YT	28	* $DragonFly: src/sys/dev/acpica5/acpi_timer.c,v 1.13 2007/10/09 09:46:56 y0netan1 Exp $
5ed44076 MD	29	*/
	30	#include "opt_acpi.h"
	31	#include <sys/param.h>
	32	#include <sys/bus.h>
	33	#include <sys/kernel.h>
49e48b8a	34	#include <sys/module.h>
5ed44076	35	#include <sys/sysctl.h>
7817ea35	36	#include <sys/systimer.h>
1f7ab7c9	37	#include <sys/rman.h>
5ed44076	38
7817ea35	39	#include <machine/lock.h>
5ed44076 MD	40	#include <bus/pci/pcivar.h>
	41
	42	#include "acpi.h"
da42c799	43	#include "accommon.h"
5ed44076 MD	44	#include "acpivar.h"
5ed44076 MD	45
5ed44076 MD	46	/*
	47	* A timecounter based on the free-running ACPI timer.
	48	*
	49	* Based on the i386-only mp_clock.c by <phk@FreeBSD.ORG>.
	50	*/
	51
	52	/* Hooks for the ACPI CA debugging infrastructure */
f9d8cd12	53	#define _COMPONENT ACPI_TIMER
5ed44076 MD	54	ACPI_MODULE_NAME("TIMER")
5ed44076 MD	55
f9d8cd12 MD	56	static device_t acpi_timer_dev;
	57	static struct resource *acpi_timer_reg;
	58	static bus_space_handle_t acpi_timer_bsh;
	59	static bus_space_tag_t acpi_timer_bst;
7817ea35 MD	60	static sysclock_t acpi_counter_mask;
	61	static sysclock_t acpi_last_counter;
	62
	63	#define ACPI_TIMER_FREQ (14318182 / 4)
	64
	65	static sysclock_t acpi_timer_get_timecount(void);
	66	static sysclock_t acpi_timer_get_timecount24(void);
	67	static sysclock_t acpi_timer_get_timecount_safe(void);
	68	static void acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock);
	69
	70	static struct cputimer acpi_cputimer = {
d8fdd978	71	SLIST_ENTRY_INITIALIZER,
7817ea35 MD	72	"ACPI",
	73	CPUTIMER_PRI_ACPI,
	74	CPUTIMER_ACPI,
	75	acpi_timer_get_timecount_safe,
	76	cputimer_default_fromhz,
	77	cputimer_default_fromus,
	78	acpi_timer_construct,
	79	cputimer_default_destruct,
	80	ACPI_TIMER_FREQ,
	81	0, 0, 0
	82	};
5ed44076	83
39b5d600	84	static int acpi_timer_identify(driver_t *driver, device_t parent);
5ed44076 MD	85	static int acpi_timer_probe(device_t dev);
5ed44076 MD	86	static int acpi_timer_attach(device_t dev);
5ed44076	87	static int acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS);
5ed44076	88
f9d8cd12 MD	89	static u_int acpi_timer_read(void);
f9d8cd12 MD	90	static int acpi_timer_test(void);
5ed44076 MD	91
	92	static device_method_t acpi_timer_methods[] = {
	93	DEVMETHOD(device_identify, acpi_timer_identify),
	94	DEVMETHOD(device_probe, acpi_timer_probe),
	95	DEVMETHOD(device_attach, acpi_timer_attach),
	96
	97	{0, 0}
	98	};
	99
	100	static driver_t acpi_timer_driver = {
	101	"acpi_timer",
	102	acpi_timer_methods,
	103	0,
	104	};
	105
	106	static devclass_t acpi_timer_devclass;
	107	DRIVER_MODULE(acpi_timer, acpi, acpi_timer_driver, acpi_timer_devclass, 0, 0);
f9d8cd12	108	MODULE_DEPEND(acpi_timer, acpi, 1, 1, 1);
5ed44076	109
f9d8cd12	110	static u_int
c436375a	111	acpi_timer_read(void)
5ed44076	112	{
f9d8cd12	113	return (bus_space_read_4(acpi_timer_bst, acpi_timer_bsh, 0));
5ed44076 MD	114	}
5ed44076 MD	115
5ed44076 MD	116	/*
	117	* Locate the ACPI timer using the FADT, set up and allocate the I/O resources
	118	* we will be using.
	119	*/
39b5d600	120	static int
5ed44076 MD	121	acpi_timer_identify(driver_t *driver, device_t parent)
5ed44076 MD	122	{
3e5760cd YT	123	device_t dev;
	124	u_long rlen, rstart;
	125	int rid, rtype;
5ed44076	126
39b5d600 MD	127	/*
	128	* Just try once, do nothing if the 'acpi' bus is rescanned.
	129	*/
	130	if (device_get_state(parent) == DS_ATTACHED)
	131	return (0);
	132
5ed44076 MD	133	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
5ed44076 MD	134
3e5760cd	135	if (acpi_disabled("timer") \|\| acpi_timer_dev)
39b5d600	136	return (ENXIO);
f9d8cd12	137
2581072f	138	if ((dev = BUS_ADD_CHILD(parent, parent, 0, "acpi_timer", 0)) == NULL) {
5ed44076	139	device_printf(parent, "could not add acpi_timer0\n");
39b5d600	140	return (ENXIO);
5ed44076 MD	141	}
	142	acpi_timer_dev = dev;
	143
	144	rid = 0;
3e5760cd YT	145	rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
3e5760cd YT	146	SYS_RES_IOPORT : SYS_RES_MEMORY;
e1eeedd0	147	rlen = AcpiGbl_FADT.PmTimerLength;
e1eeedd0	148	rstart = AcpiGbl_FADT.XPmTimerBlock.Address;
3e5760cd YT	149	if (bus_set_resource(dev, rtype, rid, rstart, rlen)) {
	150	device_printf(dev, "couldn't set resource (%s 0x%lx+0x%lx)\n",
	151	(rtype == SYS_RES_IOPORT) ? "port" : "mem", rstart, rlen);
	152	return (ENXIO);
	153	}
	154	return (0);
	155	}
	156
	157	static int
	158	acpi_timer_probe(device_t dev)
	159	{
	160	char desc[40];
	161	int i, j, rid, rtype;
	162
	163	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
	164
	165	if (dev != acpi_timer_dev)
	166	return (ENXIO);
	167
	168	rid = 0;
	169	rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
	170	SYS_RES_IOPORT : SYS_RES_MEMORY;
f9d8cd12	171	acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
5ed44076	172	if (acpi_timer_reg == NULL) {
3e5760cd YT	173	device_printf(dev, "couldn't allocate resource (%s 0x%lx)\n",
	174	(rtype == SYS_RES_IOPORT) ? "port" : "mem",
	175	(u_long)AcpiGbl_FADT.XPmTimerBlock.Address);
39b5d600	176	return (ENXIO);
5ed44076	177	}
f9d8cd12 MD	178	acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
f9d8cd12 MD	179	acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
e1eeedd0	180	if ((AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) != 0)
7817ea35	181	acpi_counter_mask = 0xffffffff;
f9d8cd12	182	else
7817ea35	183	acpi_counter_mask = 0x00ffffff;
5ed44076	184
f9d8cd12 MD	185	/*
	186	* If all tests of the counter succeed, use the ACPI-fast method. If
	187	* at least one failed, default to using the safe routine, which reads
	188	* the timer multiple times to get a consistent value before returning.
	189	*/
5ed44076	190	j = 0;
f9d8cd12 MD	191	for (i = 0; i < 10; i++)
f9d8cd12 MD	192	j += acpi_timer_test();
5ed44076	193	if (j == 10) {
7817ea35 MD	194	if (acpi_counter_mask == 0xffffffff) {
	195	acpi_cputimer.name = "ACPI-fast";
	196	acpi_cputimer.count = acpi_timer_get_timecount;
	197	} else {
	198	acpi_cputimer.name = "ACPI-fast24";
	199	acpi_cputimer.count = acpi_timer_get_timecount24;
	200	}
5ed44076	201	} else {
50e6791e SZ	202	if (acpi_counter_mask == 0xffffffff)
	203	acpi_cputimer.name = "ACPI-safe";
	204	else
	205	acpi_cputimer.name = "ACPI-safe24";
7817ea35	206	acpi_cputimer.count = acpi_timer_get_timecount_safe;
5ed44076	207	}
5ed44076	208
f8c7a42d	209	ksprintf(desc, "%d-bit timer at 3.579545MHz",
e1eeedd0	210	(AcpiGbl_FADT.Flags & ACPI_FADT_32BIT_TIMER) ? 32 : 24);
5ed44076 MD	211	device_set_desc_copy(dev, desc);
5ed44076 MD	212
7817ea35 MD	213	cputimer_register(&acpi_cputimer);
7817ea35 MD	214	cputimer_select(&acpi_cputimer, 0);
3e5760cd YT	215	/* Release the resource, we'll allocate it again during attach. */
3e5760cd YT	216	bus_release_resource(dev, rtype, rid, acpi_timer_reg);
39b5d600	217	return (0);
5ed44076 MD	218	}
	219
	220	static int
3e5760cd	221	acpi_timer_attach(device_t dev)
5ed44076	222	{
3e5760cd	223	int rid, rtype;
5ed44076	224
3e5760cd	225	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
5ed44076	226
3e5760cd YT	227	rid = 0;
	228	rtype = AcpiGbl_FADT.XPmTimerBlock.SpaceId ?
	229	SYS_RES_IOPORT : SYS_RES_MEMORY;
	230	acpi_timer_reg = bus_alloc_resource_any(dev, rtype, &rid, RF_ACTIVE);
	231	if (acpi_timer_reg == NULL)
	232	return (ENXIO);
	233	acpi_timer_bsh = rman_get_bushandle(acpi_timer_reg);
	234	acpi_timer_bst = rman_get_bustag(acpi_timer_reg);
5ed44076 MD	235	return (0);
	236	}
	237
	238	/*
7817ea35 MD	239	* Construct the timer. Adjust the base so the system clock does not
	240	* jump weirdly.
	241	*/
	242	static void
	243	acpi_timer_construct(struct cputimer *timer, sysclock_t oldclock)
	244	{
	245	timer->base = 0;
	246	timer->base = oldclock - acpi_timer_get_timecount_safe();
	247	}
	248
	249	/*
5ed44076	250	* Fetch current time value from reliable hardware.
7817ea35 MD	251	*
	252	* The cputimer interface requires a 32 bit return value. If the ACPI timer
	253	* is only 24 bits then we have to keep track of the upper 8 bits on our
	254	* own.
	255	*
	256	* XXX we could probably get away with using a per-cpu field for this and
	257	* just use interrupt disablement instead of clock_lock.
5ed44076	258	*/
7817ea35 MD	259	static sysclock_t
7817ea35 MD	260	acpi_timer_get_timecount24(void)
5ed44076	261	{
7817ea35 MD	262	sysclock_t counter;
	263
	264	clock_lock();
	265	counter = acpi_timer_read();
	266	if (counter < acpi_last_counter)
	267	acpi_cputimer.base += 0x01000000;
	268	acpi_last_counter = counter;
	269	counter += acpi_cputimer.base;
	270	clock_unlock();
	271	return (counter);
	272	}
	273
	274	static sysclock_t
	275	acpi_timer_get_timecount(void)
	276	{
	277	return (acpi_timer_read() + acpi_cputimer.base);
5ed44076 MD	278	}
	279
	280	/*
	281	* Fetch current time value from hardware that may not correctly
f9d8cd12 MD	282	* latch the counter. We need to read until we have three monotonic
	283	* samples and then use the middle one, otherwise we are not protected
	284	* against the fact that the bits can be wrong in two directions. If
	285	* we only cared about monosity, two reads would be enough.
5ed44076	286	*/
7817ea35 MD	287	static sysclock_t
7817ea35 MD	288	acpi_timer_get_timecount_safe(void)
5ed44076	289	{
f9d8cd12	290	u_int u1, u2, u3;
5ed44076	291
7817ea35 MD	292	if (acpi_counter_mask != 0xffffffff)
	293	clock_lock();
	294
f9d8cd12 MD	295	u2 = acpi_timer_read();
f9d8cd12 MD	296	u3 = acpi_timer_read();
5ed44076 MD	297	do {
	298	u1 = u2;
	299	u2 = u3;
f9d8cd12 MD	300	u3 = acpi_timer_read();
f9d8cd12 MD	301	} while (u1 > u2 \|\| u2 > u3);
5ed44076	302
7817ea35 MD	303	if (acpi_counter_mask != 0xffffffff) {
	304	if (u2 < acpi_last_counter)
	305	acpi_cputimer.base += 0x01000000;
	306	acpi_last_counter = u2;
	307	clock_unlock();
	308	}
	309	return (u2 + acpi_cputimer.base);
5ed44076 MD	310	}
	311
	312	/*
	313	* Timecounter freqency adjustment interface.
	314	*/
	315	static int
	316	acpi_timer_sysctl_freq(SYSCTL_HANDLER_ARGS)
	317	{
	318	int error;
	319	u_int freq;
	320
7817ea35	321	if (acpi_cputimer.freq == 0)
5ed44076	322	return (EOPNOTSUPP);
7817ea35	323	freq = acpi_cputimer.freq;
5ed44076	324	error = sysctl_handle_int(oidp, &freq, sizeof(freq), req);
7817ea35 MD	325	if (error == 0 && req->newptr != NULL)
7817ea35 MD	326	cputimer_set_frequency(&acpi_cputimer, freq);
5ed44076 MD	327
	328	return (error);
	329	}
	330
	331	SYSCTL_PROC(_machdep, OID_AUTO, acpi_timer_freq, CTLTYPE_INT \| CTLFLAG_RW,
	332	0, sizeof(u_int), acpi_timer_sysctl_freq, "I", "");
	333
	334	/*
5ed44076	335	* Some ACPI timers are known or believed to suffer from implementation
f9d8cd12 MD	336	* problems which can lead to erroneous values being read. This function
	337	* tests for consistent results from the timer and returns 1 if it believes
	338	* the timer is consistent, otherwise it returns 0.
5ed44076	339	*
f9d8cd12 MD	340	* It appears the cause is that the counter is not latched to the PCI bus
f9d8cd12 MD	341	* clock when read:
5ed44076 MD	342	*
	343	* ] 20. ACPI Timer Errata
	344	* ]
	345	* ] Problem: The power management timer may return improper result when
	346	* ] read. Although the timer value settles properly after incrementing,
	347	* ] while incrementing there is a 3nS window every 69.8nS where the
	348	* ] timer value is indeterminate (a 4.2% chance that the data will be
	349	* ] incorrect when read). As a result, the ACPI free running count up
	350	* ] timer specification is violated due to erroneous reads. Implication:
	351	* ] System hangs due to the "inaccuracy" of the timer when used by
	352	* ] software for time critical events and delays.
	353	* ]
	354	* ] Workaround: Read the register twice and compare.
	355	* ] Status: This will not be fixed in the PIIX4 or PIIX4E, it is fixed
	356	* ] in the PIIX4M.
5ed44076	357	*/
7817ea35	358
f9d8cd12	359	static int
c436375a	360	acpi_timer_test(void)
f9d8cd12 MD	361	{
	362	uint32_t last, this;
	363	int min, max, n, delta;
	364	register_t s;
5ed44076	365
f9d8cd12 MD	366	min = 10000000;
f9d8cd12 MD	367	max = 0;
5ed44076	368
f9d8cd12	369	/* Test the timer with interrupts disabled to get accurate results. */
e774ca6d	370	#if defined(__i386__)
7817ea35	371	s = read_eflags();
c1543a89	372	#elif defined(__x86_64__)
e774ca6d MD	373	s = read_rflags();
	374	#else
	375	#error "no read_eflags"
	376	#endif
7817ea35	377	cpu_disable_intr();
f9d8cd12	378	last = acpi_timer_read();
7817ea35	379	for (n = 0; n < 2000; n++) {
f9d8cd12 MD	380	this = acpi_timer_read();
	381	delta = acpi_TimerDelta(this, last);
	382	if (delta > max)
	383	max = delta;
	384	else if (delta < min)
	385	min = delta;
	386	last = this;
	387	}
e774ca6d	388	#if defined(__i386__)
7817ea35	389	write_eflags(s);
c1543a89	390	#elif defined(__x86_64__)
e774ca6d MD	391	write_rflags(s);
	392	#else
	393	#error "no read_eflags"
	394	#endif
5ed44076	395
f9d8cd12 MD	396	if (max - min > 2)
	397	n = 0;
	398	else if (min < 0 \|\| max == 0)
	399	n = 0;
	400	else
	401	n = 1;
	402	if (bootverbose) {
e3869ec7	403	kprintf("ACPI timer looks %s min = %d, max = %d, width = %d\n",
f9d8cd12 MD	404	n ? "GOOD" : "BAD ",
	405	min, max, max - min);
	406	}
5ed44076	407
f9d8cd12 MD	408	return (n);
f9d8cd12 MD	409	}
5ed44076	410