static void
AeHardwareInterfaces (
    void)
{
    ACPI_STATUS             Status;
    UINT32                  Value;


    Status = AcpiWriteBitRegister (ACPI_BITREG_WAKE_STATUS, 1);
    AE_CHECK_OK (AcpiWriteBitRegister, Status);

    Status = AcpiWriteBitRegister (ACPI_BITREG_GLOBAL_LOCK_ENABLE, 1);
    AE_CHECK_OK (AcpiWriteBitRegister, Status);

    Status = AcpiWriteBitRegister (ACPI_BITREG_SLEEP_ENABLE, 1);
    AE_CHECK_OK (AcpiWriteBitRegister, Status);

    Status = AcpiWriteBitRegister (ACPI_BITREG_ARB_DISABLE, 1);
    AE_CHECK_OK (AcpiWriteBitRegister, Status);


    Status = AcpiReadBitRegister (ACPI_BITREG_WAKE_STATUS, &Value);
    AE_CHECK_OK (AcpiReadBitRegister, Status);

    Status = AcpiReadBitRegister (ACPI_BITREG_GLOBAL_LOCK_ENABLE, &Value);
    AE_CHECK_OK (AcpiReadBitRegister, Status);

    Status = AcpiReadBitRegister (ACPI_BITREG_SLEEP_ENABLE, &Value);
    AE_CHECK_OK (AcpiReadBitRegister, Status);

    Status = AcpiReadBitRegister (ACPI_BITREG_ARB_DISABLE, &Value);
    AE_CHECK_OK (AcpiReadBitRegister, Status);
}

static ACPI_STATUS
AcpiEvFixedEventInitialize (
    void)
{
    UINT32                  i;
    ACPI_STATUS             Status;


    /*
     * Initialize the structure that keeps track of fixed event handlers and
     * enable the fixed events.
     */
    for (i = 0; i < ACPI_NUM_FIXED_EVENTS; i++)
    {
        AcpiGbl_FixedEventHandlers[i].Handler = NULL;
        AcpiGbl_FixedEventHandlers[i].Context = NULL;

        /* Disable the fixed event */

        if (AcpiGbl_FixedEventInfo[i].EnableRegisterId != 0xFF)
        {
            Status = AcpiWriteBitRegister (
                AcpiGbl_FixedEventInfo[i].EnableRegisterId,
                ACPI_DISABLE_EVENT);
            if (ACPI_FAILURE (Status))
            {
                return (Status);
            }
        }
    }

    return (AE_OK);
}

ACPI_STATUS
AcpiClearEvent (
    UINT32                  Event)
{
    ACPI_STATUS             Status = AE_OK;


    ACPI_FUNCTION_TRACE (AcpiClearEvent);


    /* Decode the Fixed Event */

    if (Event > ACPI_EVENT_MAX)
    {
        return_ACPI_STATUS (AE_BAD_PARAMETER);
    }

    /*
     * Clear the requested fixed event (By writing a one to the status
     * register bit)
     */
    Status = AcpiWriteBitRegister (
                AcpiGbl_FixedEventInfo[Event].StatusRegisterId,
                ACPI_CLEAR_STATUS);

    return_ACPI_STATUS (Status);
}

static void
acpi_cst_c3_bm_rld_handler(struct cpuhelper_msg *msg)
{

    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
    cpuhelper_replymsg(msg, 0);
}

ACPI_STATUS
AcpiEnterSleepStateS4bios (
    void)
{
    UINT32                  InValue;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE (AcpiEnterSleepStateS4bios);


    /* Clear the wake status bit (PM1) */

    Status = AcpiWriteBitRegister (ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    Status = AcpiHwClearAcpiStatus ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /*
     * 1) Disable/Clear all GPEs
     * 2) Enable all wakeup GPEs
     */
    Status = AcpiHwDisableAllGpes ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }
    AcpiGbl_SystemAwakeAndRunning = FALSE;

    Status = AcpiHwEnableAllWakeupGpes ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    ACPI_FLUSH_CPU_CACHE ();

    Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand,
        (UINT32) AcpiGbl_FADT.S4BiosRequest, 8);

    do {
        AcpiOsStall (ACPI_USEC_PER_MSEC);
        Status = AcpiReadBitRegister (ACPI_BITREG_WAKE_STATUS, &InValue);
        if (ACPI_FAILURE (Status))
        {
            return_ACPI_STATUS (Status);
        }

    } while (!InValue);

    return_ACPI_STATUS (AE_OK);
}

static void
acpi_cst_c3_bm_rld_handler(netmsg_t msg)
{
    struct netmsg_acpi_cst *rmsg = (struct netmsg_acpi_cst *)msg;

    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
    lwkt_replymsg(&rmsg->base.lmsg, 0);
}

static void
AeHardwareInterfaces (
    void)
{
#if (!ACPI_REDUCED_HARDWARE)

    ACPI_STATUS             Status;
    UINT32                  Value;


    /* If Hardware Reduced flag is set, we are all done */

    if (AcpiGbl_ReducedHardware)
    {
        return;
    }

    Status = AcpiWriteBitRegister (ACPI_BITREG_WAKE_STATUS, 1);
    ACPI_CHECK_OK (AcpiWriteBitRegister, Status);

    Status = AcpiWriteBitRegister (ACPI_BITREG_GLOBAL_LOCK_ENABLE, 1);
    ACPI_CHECK_OK (AcpiWriteBitRegister, Status);

    Status = AcpiWriteBitRegister (ACPI_BITREG_SLEEP_ENABLE, 1);
    ACPI_CHECK_OK (AcpiWriteBitRegister, Status);

    Status = AcpiWriteBitRegister (ACPI_BITREG_ARB_DISABLE, 1);
    ACPI_CHECK_OK (AcpiWriteBitRegister, Status);


    Status = AcpiReadBitRegister (ACPI_BITREG_WAKE_STATUS, &Value);
    ACPI_CHECK_OK (AcpiReadBitRegister, Status);

    Status = AcpiReadBitRegister (ACPI_BITREG_GLOBAL_LOCK_ENABLE, &Value);
    ACPI_CHECK_OK (AcpiReadBitRegister, Status);

    Status = AcpiReadBitRegister (ACPI_BITREG_SLEEP_ENABLE, &Value);
    ACPI_CHECK_OK (AcpiReadBitRegister, Status);

    Status = AcpiReadBitRegister (ACPI_BITREG_ARB_DISABLE, &Value);
    ACPI_CHECK_OK (AcpiReadBitRegister, Status);

#endif /* !ACPI_REDUCED_HARDWARE */
}

ACPI_STATUS
AcpiEnableEvent (
    UINT32                  Event,
    UINT32                  Flags)
{
    ACPI_STATUS             Status = AE_OK;
    UINT32                  Value;


    ACPI_FUNCTION_TRACE (AcpiEnableEvent);


    /* If Hardware Reduced flag is set, there are no fixed events */

    if (AcpiGbl_ReducedHardware)
    {
        return_ACPI_STATUS (AE_OK);
    }

    /* Decode the Fixed Event */

    if (Event > ACPI_EVENT_MAX)
    {
        return_ACPI_STATUS (AE_BAD_PARAMETER);
    }

    /*
     * Enable the requested fixed event (by writing a one to the enable
     * register bit)
     */
    Status = AcpiWriteBitRegister (
        AcpiGbl_FixedEventInfo[Event].EnableRegisterId,
        ACPI_ENABLE_EVENT);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /* Make sure that the hardware responded */

    Status = AcpiReadBitRegister (
        AcpiGbl_FixedEventInfo[Event].EnableRegisterId, &Value);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    if (Value != 1)
    {
        ACPI_ERROR ((AE_INFO,
            "Could not enable %s event", AcpiUtGetEventName (Event)));
        return_ACPI_STATUS (AE_NO_HARDWARE_RESPONSE);
    }

    return_ACPI_STATUS (Status);
}

static bool
acpicpu_cstate_bm_check(void)
{
	uint32_t val = 0;
	ACPI_STATUS rv;

	rv = AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, &val);

	if (ACPI_FAILURE(rv) || val == 0)
		return false;

	(void)AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);

	return true;
}

static UINT32
AcpiEvFixedEventDispatch (
    UINT32                  Event)
{

    ACPI_FUNCTION_ENTRY ();


    /* Clear the status bit */

    (void) AcpiWriteBitRegister (
        AcpiGbl_FixedEventInfo[Event].StatusRegisterId,
        ACPI_CLEAR_STATUS);

    /*
     * Make sure that a handler exists. If not, report an error
     * and disable the event to prevent further interrupts.
     */
    if (!AcpiGbl_FixedEventHandlers[Event].Handler)
    {
        (void) AcpiWriteBitRegister (
            AcpiGbl_FixedEventInfo[Event].EnableRegisterId,
            ACPI_DISABLE_EVENT);

        ACPI_ERROR ((AE_INFO,
            "No installed handler for fixed event - %s (%u), disabling",
            AcpiUtGetEventName (Event), Event));

        return (ACPI_INTERRUPT_NOT_HANDLED);
    }

    /* Invoke the Fixed Event handler */

    return ((AcpiGbl_FixedEventHandlers[Event].Handler)(
        AcpiGbl_FixedEventHandlers[Event].Context));
}

static UINT32
AcpiEvFixedEventDispatch (
    UINT32                  Event)
{

    ACPI_FUNCTION_ENTRY ();


    /* Clear the status bit */

    (void) AcpiWriteBitRegister (
            AcpiGbl_FixedEventInfo[Event].StatusRegisterId,
            ACPI_CLEAR_STATUS);

    /*
     * Make sure we've got a handler. If not, report an error. The event is
     * disabled to prevent further interrupts.
     */
    if (NULL == AcpiGbl_FixedEventHandlers[Event].Handler)
    {
        (void) AcpiWriteBitRegister (
                AcpiGbl_FixedEventInfo[Event].EnableRegisterId,
                ACPI_DISABLE_EVENT);

        ACPI_ERROR ((AE_INFO,
            "No installed handler for fixed event [0x%08X]",
            Event));

        return (ACPI_INTERRUPT_NOT_HANDLED);
    }

    /* Invoke the Fixed Event handler */

    return ((AcpiGbl_FixedEventHandlers[Event].Handler)(
                AcpiGbl_FixedEventHandlers[Event].Context));
}

ACPI_STATUS
AcpiDisableEvent (
    UINT32                  Event,
    UINT32                  Flags)
{
    ACPI_STATUS             Status = AE_OK;
    UINT32                  Value;


    ACPI_FUNCTION_TRACE (AcpiDisableEvent);


    /* Decode the Fixed Event */

    if (Event > ACPI_EVENT_MAX)
    {
        return_ACPI_STATUS (AE_BAD_PARAMETER);
    }

    /*
     * Disable the requested fixed event (by writing a zero to the enable
     * register bit)
     */
    Status = AcpiWriteBitRegister (
                AcpiGbl_FixedEventInfo[Event].EnableRegisterId,
                ACPI_DISABLE_EVENT);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    Status = AcpiReadBitRegister (
                AcpiGbl_FixedEventInfo[Event].EnableRegisterId, &Value);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    if (Value != 0)
    {
        ACPI_ERROR ((AE_INFO,
            "Could not disable %s events", AcpiUtGetEventName (Event)));
        return_ACPI_STATUS (AE_NO_HARDWARE_RESPONSE);
    }

    return_ACPI_STATUS (Status);
}

ACPI_STATUS
AcpiEvReleaseGlobalLock (
    void)
{
    BOOLEAN                 Pending = FALSE;
    ACPI_STATUS             Status = AE_OK;


    ACPI_FUNCTION_TRACE (EvReleaseGlobalLock);


    /* Lock must be already acquired */

    if (!AcpiGbl_GlobalLockAcquired)
    {
        ACPI_WARNING ((AE_INFO,
            "Cannot release the ACPI Global Lock, it has not been acquired"));
        return_ACPI_STATUS (AE_NOT_ACQUIRED);
    }

    if (AcpiGbl_GlobalLockPresent)
    {
        /* Allow any thread to release the lock */

        ACPI_RELEASE_GLOBAL_LOCK (AcpiGbl_FACS, Pending);

        /*
         * If the pending bit was set, we must write GBL_RLS to the control
         * register
         */
        if (Pending)
        {
            Status = AcpiWriteBitRegister (
                        ACPI_BITREG_GLOBAL_LOCK_RELEASE, ACPI_ENABLE_EVENT);
        }

        ACPI_DEBUG_PRINT ((ACPI_DB_EXEC, "Released hardware Global Lock\n"));
    }

    AcpiGbl_GlobalLockAcquired = FALSE;

    /* Release the local GL mutex */

    AcpiOsReleaseMutex (AcpiGbl_GlobalLockMutex->Mutex.OsMutex);
    return_ACPI_STATUS (Status);
}

//.........这里部分代码省略.........
	if (cx_ptr->gas.SpaceId != ACPI_ADR_SPACE_FIXED_HARDWARE)
	    sc->cst_flags &= ~ACPI_CST_FLAG_MATCH_HT;

	cx_ptr->rid = sc->cst_parent->cpu_next_rid;
	acpi_bus_alloc_gas(sc->cst_dev, &cx_ptr->res_type, &cx_ptr->rid,
	    &cx_ptr->gas, &cx_ptr->res, RF_SHAREABLE);
	if (cx_ptr->res != NULL) {
	    sc->cst_parent->cpu_next_rid++;
	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
			     "cpu_cst%d: Got C%d - %d latency\n",
			     device_get_unit(sc->cst_dev), cx_ptr->type,
			     cx_ptr->trans_lat));
	    cx_ptr->enter = acpi_cst_cx_io_enter;
	    cx_ptr->btag = rman_get_bustag(cx_ptr->res);
	    cx_ptr->bhand = rman_get_bushandle(cx_ptr->res);
	    error = acpi_cst_cx_setup(cx_ptr);
	    if (error)
		panic("C%d CST I/O setup failed: %d", cx_ptr->type, error);
	    cx_ptr++;
	    sc->cst_cx_count++;
	} else {
	    error = acpi_cst_cx_setup(cx_ptr);
	    if (!error) {
		KASSERT(cx_ptr->enter != NULL,
		    ("C%d enter is not set", cx_ptr->type));
		cx_ptr++;
		sc->cst_cx_count++;
	    }
	}
    }
    AcpiOsFree(buf.Pointer);

    if (sc->cst_flags & ACPI_CST_FLAG_MATCH_HT) {
	cpumask_t mask;

	mask = get_cpumask_from_level(sc->cst_cpuid, CORE_LEVEL);
	if (CPUMASK_TESTNZERO(mask)) {
	    int cpu;

	    for (cpu = 0; cpu < ncpus; ++cpu) {
		struct acpi_cst_softc *sc1 = acpi_cst_softc[cpu];

		if (sc1 == NULL || sc1 == sc ||
		    (sc1->cst_flags & ACPI_CST_FLAG_ATTACHED) == 0 ||
		    (sc1->cst_flags & ACPI_CST_FLAG_MATCH_HT) == 0)
		    continue;
		if (!CPUMASK_TESTBIT(mask, sc1->cst_cpuid))
		    continue;

		if (sc1->cst_cx_count != sc->cst_cx_count) {
		    struct acpi_cst_softc *src_sc, *dst_sc;

		    if (bootverbose) {
			device_printf(sc->cst_dev,
			    "inconstent C-state count: %d, %s has %d\n",
			    sc->cst_cx_count,
			    device_get_nameunit(sc1->cst_dev),
			    sc1->cst_cx_count);
		    }
		    if (sc1->cst_cx_count > sc->cst_cx_count) {
			src_sc = sc1;
			dst_sc = sc;
		    } else {
			src_sc = sc;
			dst_sc = sc1;
		    }
		    acpi_cst_copy(dst_sc, src_sc);
		}
	    }
	}
    }

    if (reprobe) {
	/* If there are C3(+) states, always enable bus master wakeup */
	if ((acpi_cst_quirks & ACPI_CST_QUIRK_NO_BM) == 0) {
	    for (i = 0; i < sc->cst_cx_count; ++i) {
		struct acpi_cst_cx *cx = &sc->cst_cx_states[i];

		if (cx->type >= ACPI_STATE_C3) {
		    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
		    break;
		}
	    }
	}

	/* Fix up the lowest Cx being used */
	acpi_cst_set_lowest_oncpu(sc, sc->cst_cx_lowest_req);
    }

    /*
     * Cache the lowest non-C3 state.
     * NOTE: must after cst_cx_lowest is set.
     */
    acpi_cst_non_c3(sc);

    cpu_sfence();
    sc->cst_flags &= ~ACPI_CST_FLAG_PROBING;

    return (0);
}

/*
 * Idle the CPU in the lowest state possible.  This function is called with
 * interrupts disabled.  Note that once it re-enables interrupts, a task
 * switch can occur so do not access shared data (i.e. the softc) after
 * interrupts are re-enabled.
 */
static void
acpi_cst_idle(void)
{
    struct	acpi_cst_softc *sc;
    struct	acpi_cst_cx *cx_next;
    union microtime_pcpu start, end;
    int		cx_next_idx, i, tdiff, bm_arb_disabled = 0;

    /* If disabled, return immediately. */
    if (acpi_cst_disable_idle) {
	ACPI_ENABLE_IRQS();
	return;
    }

    /*
     * Look up our CPU id to get our softc.  If it's NULL, we'll use C1
     * since there is no Cx state for this processor.
     */
    sc = acpi_cst_softc[mdcpu->mi.gd_cpuid];
    if (sc == NULL) {
	acpi_cst_c1_halt();
	return;
    }

    /* Still probing; use C1 */
    if (sc->cst_flags & ACPI_CST_FLAG_PROBING) {
	acpi_cst_c1_halt();
	return;
    }

    /* Find the lowest state that has small enough latency. */
    cx_next_idx = 0;
    for (i = sc->cst_cx_lowest; i >= 0; i--) {
	if (sc->cst_cx_states[i].trans_lat * 3 <= sc->cst_prev_sleep) {
	    cx_next_idx = i;
	    break;
	}
    }

    /*
     * Check for bus master activity if needed for the selected state.
     * If there was activity, clear the bit and use the lowest non-C3 state.
     */
    cx_next = &sc->cst_cx_states[cx_next_idx];
    if (cx_next->flags & ACPI_CST_CX_FLAG_BM_STS) {
	int bm_active;

	AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, &bm_active);
	if (bm_active != 0) {
	    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);
	    cx_next_idx = sc->cst_non_c3;
	}
    }

    /* Select the next state and update statistics. */
    cx_next = &sc->cst_cx_states[cx_next_idx];
    sc->cst_cx_stats[cx_next_idx]++;
    KASSERT(cx_next->type != ACPI_STATE_C0, ("C0 sleep"));

    /*
     * Execute HLT (or equivalent) and wait for an interrupt.  We can't
     * calculate the time spent in C1 since the place we wake up is an
     * ISR.  Assume we slept half of quantum and return.
     */
    if (cx_next->type == ACPI_STATE_C1) {
	sc->cst_prev_sleep = (sc->cst_prev_sleep * 3 + 500000 / hz) / 4;
	cx_next->enter(cx_next);
	return;
    }

    /* Execute the proper preamble before enter the selected state. */
    if (cx_next->preamble == ACPI_CST_CX_PREAMBLE_BM_ARB) {
	AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 1);
	bm_arb_disabled = 1;
    } else if (cx_next->preamble == ACPI_CST_CX_PREAMBLE_WBINVD) {
	ACPI_FLUSH_CPU_CACHE();
    }

    /*
     * Enter the selected state and check time spent asleep.
     */
    microtime_pcpu_get(&start);
    cpu_mfence();

    cx_next->enter(cx_next);

    cpu_mfence();
    microtime_pcpu_get(&end);

    /* Enable bus master arbitration, if it was disabled. */
    if (bm_arb_disabled)
	AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 0);

    ACPI_ENABLE_IRQS();
//.........这里部分代码省略.........

status_t
write_bit_register(uint32 regid, uint32 val)
{
    return AcpiWriteBitRegister(regid, val);
}

//.........这里部分代码省略.........
            /* Clear the SLP_EN and SLP_TYP fields */

            Pm1aControl &= ~(SleepTypeRegInfo->AccessBitMask |
                SleepEnableRegInfo->AccessBitMask);
            Pm1bControl = Pm1aControl;

            /* Insert the SLP_TYP bits */

            Pm1aControl |= (AcpiGbl_SleepTypeA <<
                SleepTypeRegInfo->BitPosition);
            Pm1bControl |= (AcpiGbl_SleepTypeB <<
                SleepTypeRegInfo->BitPosition);

            /* Write the control registers and ignore any errors */

            (void) AcpiHwWritePm1Control (Pm1aControl, Pm1bControl);
        }
    }

    /* Ensure EnterSleepStatePrep -> EnterSleepState ordering */

    AcpiGbl_SleepTypeA = ACPI_SLEEP_TYPE_INVALID;

    /* Setup parameter object */

    ArgList.Count = 1;
    ArgList.Pointer = &Arg;
    Arg.Type = ACPI_TYPE_INTEGER;

    /* Ignore any errors from these methods */

    Arg.Integer.Value = ACPI_SST_WAKING;
    Status = AcpiEvaluateObject (NULL, METHOD_NAME__SST, &ArgList, NULL);
    if (ACPI_FAILURE (Status) && Status != AE_NOT_FOUND)
    {
        ACPI_EXCEPTION ((AE_INFO, Status, "During Method _SST"));
    }

    Arg.Integer.Value = SleepState;
    Status = AcpiEvaluateObject (NULL, METHOD_NAME__BFS, &ArgList, NULL);
    if (ACPI_FAILURE (Status) && Status != AE_NOT_FOUND)
    {
        ACPI_EXCEPTION ((AE_INFO, Status, "During Method _BFS"));
    }

    Status = AcpiEvaluateObject (NULL, METHOD_NAME__WAK, &ArgList, NULL);
    if (ACPI_FAILURE (Status) && Status != AE_NOT_FOUND)
    {
        ACPI_EXCEPTION ((AE_INFO, Status, "During Method _WAK"));
    }
    /* TBD: _WAK "sometimes" returns stuff - do we want to look at it? */

    /*
     * Restore the GPEs:
     * 1) Disable/Clear all GPEs
     * 2) Enable all runtime GPEs
     */
    Status = AcpiHwDisableAllGpes ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }
    AcpiGbl_SystemAwakeAndRunning = TRUE;

    Status = AcpiHwEnableAllRuntimeGpes ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /* Enable power button */

    (void) AcpiWriteBitRegister(
            AcpiGbl_FixedEventInfo[ACPI_EVENT_POWER_BUTTON].EnableRegisterId,
            ACPI_ENABLE_EVENT);

    (void) AcpiWriteBitRegister(
            AcpiGbl_FixedEventInfo[ACPI_EVENT_POWER_BUTTON].StatusRegisterId,
            ACPI_CLEAR_STATUS);

    /*
     * Enable BM arbitration. This feature is contained within an
     * optional register (PM2 Control), so ignore a BAD_ADDRESS
     * exception.
     */
    Status = AcpiWriteBitRegister (ACPI_BITREG_ARB_DISABLE, 0);
    if (ACPI_FAILURE (Status) && (Status != AE_BAD_ADDRESS))
    {
        return_ACPI_STATUS (Status);
    }

    Arg.Integer.Value = ACPI_SST_WORKING;
    Status = AcpiEvaluateObject (NULL, METHOD_NAME__SST, &ArgList, NULL);
    if (ACPI_FAILURE (Status) && Status != AE_NOT_FOUND)
    {
        ACPI_EXCEPTION ((AE_INFO, Status, "During Method _SST"));
    }

    return_ACPI_STATUS (Status);
}

ACPI_STATUS
AcpiEnterSleepState (
    UINT8                   SleepState)
{
    UINT32                  Pm1aControl;
    UINT32                  Pm1bControl;
    ACPI_BIT_REGISTER_INFO  *SleepTypeRegInfo;
    ACPI_BIT_REGISTER_INFO  *SleepEnableRegInfo;
    UINT32                  InValue;
    ACPI_OBJECT_LIST        ArgList;
    ACPI_OBJECT             Arg;
    ACPI_STATUS             Status;


    ACPI_FUNCTION_TRACE (AcpiEnterSleepState);


    if ((AcpiGbl_SleepTypeA > ACPI_SLEEP_TYPE_MAX) ||
        (AcpiGbl_SleepTypeB > ACPI_SLEEP_TYPE_MAX))
    {
        ACPI_ERROR ((AE_INFO, "Sleep values out of range: A=%X B=%X",
            AcpiGbl_SleepTypeA, AcpiGbl_SleepTypeB));
        return_ACPI_STATUS (AE_AML_OPERAND_VALUE);
    }

    SleepTypeRegInfo   = AcpiHwGetBitRegisterInfo (ACPI_BITREG_SLEEP_TYPE);
    SleepEnableRegInfo = AcpiHwGetBitRegisterInfo (ACPI_BITREG_SLEEP_ENABLE);

    /* Clear wake status */

    Status = AcpiWriteBitRegister (ACPI_BITREG_WAKE_STATUS, ACPI_CLEAR_STATUS);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /* Clear all fixed and general purpose status bits */

    Status = AcpiHwClearAcpiStatus ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    if (SleepState != ACPI_STATE_S5)
    {
        /*
         * Disable BM arbitration. This feature is contained within an
         * optional register (PM2 Control), so ignore a BAD_ADDRESS
         * exception.
         */
        Status = AcpiWriteBitRegister (ACPI_BITREG_ARB_DISABLE, 1);
        if (ACPI_FAILURE (Status) && (Status != AE_BAD_ADDRESS))
        {
            return_ACPI_STATUS (Status);
        }
    }

    /*
     * 1) Disable/Clear all GPEs
     * 2) Enable all wakeup GPEs
     */
    Status = AcpiHwDisableAllGpes ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }
    AcpiGbl_SystemAwakeAndRunning = FALSE;

    Status = AcpiHwEnableAllWakeupGpes ();
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }

    /* Execute the _GTS method (Going To Sleep) */

    ArgList.Count = 1;
    ArgList.Pointer = &Arg;
    Arg.Type = ACPI_TYPE_INTEGER;
    Arg.Integer.Value = SleepState;

    Status = AcpiEvaluateObject (NULL, METHOD_NAME__GTS, &ArgList, NULL);
    if (ACPI_FAILURE (Status) && Status != AE_NOT_FOUND)
    {
        return_ACPI_STATUS (Status);
    }

    /* Get current value of PM1A control */

    Status = AcpiHwRegisterRead (ACPI_REGISTER_PM1_CONTROL,
                &Pm1aControl);
    if (ACPI_FAILURE (Status))
    {
        return_ACPI_STATUS (Status);
    }
    ACPI_DEBUG_PRINT ((ACPI_DB_INIT,
        "Entering sleep state [S%d]\n", SleepState));

    /* Clear the SLP_EN and SLP_TYP fields */
//.........这里部分代码省略.........

static int
acpi_cpu_quirks(void)
{
    device_t acpi_dev;
    uint32_t val;

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

    /*
     * Bus mastering arbitration control is needed to keep caches coherent
     * while sleeping in C3.  If it's not present but a working flush cache
     * instruction is present, flush the caches before entering C3 instead.
     * Otherwise, just disable C3 completely.
     */
    if (AcpiGbl_FADT.Pm2ControlBlock == 0 ||
	AcpiGbl_FADT.Pm2ControlLength == 0) {
	if ((AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD) &&
	    (AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD_FLUSH) == 0) {
	    cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		"acpi_cpu: no BM control, using flush cache method\n"));
	} else {
	    cpu_quirks |= CPU_QUIRK_NO_C3;
	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		"acpi_cpu: no BM control, C3 not available\n"));
	}
    }

    /*
     * If we are using generic Cx mode, C3 on multiple CPUs requires using
     * the expensive flush cache instruction.
     */
    if (cpu_cx_generic && mp_ncpus > 1) {
	cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
	    "acpi_cpu: SMP, using flush cache mode for C3\n"));
    }

    /* Look for various quirks of the PIIX4 part. */
    acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
    if (acpi_dev != NULL) {
	switch (pci_get_revid(acpi_dev)) {
	/*
	 * Disable C3 support for all PIIX4 chipsets.  Some of these parts
	 * do not report the BMIDE status to the BM status register and
	 * others have a livelock bug if Type-F DMA is enabled.  Linux
	 * works around the BMIDE bug by reading the BM status directly
	 * but we take the simpler approach of disabling C3 for these
	 * parts.
	 *
	 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
	 * Livelock") from the January 2002 PIIX4 specification update.
	 * Applies to all PIIX4 models.
	 *
	 * Also, make sure that all interrupts cause a "Stop Break"
	 * event to exit from C2 state.
	 * Also, BRLD_EN_BM (ACPI_BITREG_BUS_MASTER_RLD in ACPI-speak)
	 * should be set to zero, otherwise it causes C2 to short-sleep.
	 * PIIX4 doesn't properly support C3 and bus master activity
	 * need not break out of C2.
	 */
	case PCI_REVISION_A_STEP:
	case PCI_REVISION_B_STEP:
	case PCI_REVISION_4E:
	case PCI_REVISION_4M:
	    cpu_quirks |= CPU_QUIRK_NO_C3;
	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		"acpi_cpu: working around PIIX4 bug, disabling C3\n"));

	    val = pci_read_config(acpi_dev, PIIX4_DEVACTB_REG, 4);
	    if ((val & PIIX4_STOP_BREAK_MASK) != PIIX4_STOP_BREAK_MASK) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		    "acpi_cpu: PIIX4: enabling IRQs to generate Stop Break\n"));
	    	val |= PIIX4_STOP_BREAK_MASK;
		pci_write_config(acpi_dev, PIIX4_DEVACTB_REG, val, 4);
	    }
	    AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_RLD, &val);
	    if (val) {
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
		    "acpi_cpu: PIIX4: reset BRLD_EN_BM\n"));
		AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
	    }
	    break;
	default:
	    break;
	}
    }

    return (0);
}

/*
 * Idle the CPU in the lowest state possible.  This function is called with
 * interrupts disabled.  Note that once it re-enables interrupts, a task
 * switch can occur so do not access shared data (i.e. the softc) after
 * interrupts are re-enabled.
 */
static void
acpi_cpu_idle()
{
    struct	acpi_cpu_softc *sc;
    struct	acpi_cx *cx_next;
    uint32_t	start_time, end_time;
    int		bm_active, cx_next_idx, i;

    /* If disabled, return immediately. */
    if (cpu_disable_idle) {
	ACPI_ENABLE_IRQS();
	return;
    }

    /*
     * Look up our CPU id to get our softc.  If it's NULL, we'll use C1
     * since there is no ACPI processor object for this CPU.  This occurs
     * for logical CPUs in the HTT case.
     */
    sc = cpu_softc[PCPU_GET(cpuid)];
    if (sc == NULL) {
	acpi_cpu_c1();
	return;
    }

    /* Find the lowest state that has small enough latency. */
    cx_next_idx = 0;
    for (i = sc->cpu_cx_lowest; i >= 0; i--) {
	if (sc->cpu_cx_states[i].trans_lat * 3 <= sc->cpu_prev_sleep) {
	    cx_next_idx = i;
	    break;
	}
    }

    /*
     * Check for bus master activity.  If there was activity, clear
     * the bit and use the lowest non-C3 state.  Note that the USB
     * driver polling for new devices keeps this bit set all the
     * time if USB is loaded.
     */
    if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
	AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, &bm_active);
	if (bm_active != 0) {
	    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);
	    cx_next_idx = min(cx_next_idx, sc->cpu_non_c3);
	}
    }

    /* Select the next state and update statistics. */
    cx_next = &sc->cpu_cx_states[cx_next_idx];
    sc->cpu_cx_stats[cx_next_idx]++;
    KASSERT(cx_next->type != ACPI_STATE_C0, ("acpi_cpu_idle: C0 sleep"));

    /*
     * Execute HLT (or equivalent) and wait for an interrupt.  We can't
     * calculate the time spent in C1 since the place we wake up is an
     * ISR.  Assume we slept half of quantum and return.
     */
    if (cx_next->type == ACPI_STATE_C1) {
	sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + 500000 / hz) / 4;
	acpi_cpu_c1();
	return;
    }

    /*
     * For C3, disable bus master arbitration and enable bus master wake
     * if BM control is available, otherwise flush the CPU cache.
     */
    if (cx_next->type == ACPI_STATE_C3) {
	if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
	    AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 1);
	    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
	} else
	    ACPI_FLUSH_CPU_CACHE();
    }

    /*
     * Read from P_LVLx to enter C2(+), checking time spent asleep.
     * Use the ACPI timer for measuring sleep time.  Since we need to
     * get the time very close to the CPU start/stop clock logic, this
     * is the only reliable time source.
     */
    AcpiRead(&start_time, &AcpiGbl_FADT.XPmTimerBlock);
    CPU_GET_REG(cx_next->p_lvlx, 1);

    /*
     * Read the end time twice.  Since it may take an arbitrary time
     * to enter the idle state, the first read may be executed before
     * the processor has stopped.  Doing it again provides enough
     * margin that we are certain to have a correct value.
     */
    AcpiRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
    AcpiRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);

//.........这里部分代码省略.........