Linux 4.1.16

[linux/fpc-iii.git] / drivers / acpi / sleep.c

/*
 * sleep.c - ACPI sleep support.
 *
 * Copyright (c) 2005 Alexey Starikovskiy <alexey.y.starikovskiy@intel.com>
 * Copyright (c) 2004 David Shaohua Li <shaohua.li@intel.com>
 * Copyright (c) 2000-2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 *
 * This file is released under the GPLv2.
 *
 */

#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/dmi.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/suspend.h>
#include <linux/reboot.h>
#include <linux/acpi.h>
#include <linux/module.h>
#include <asm/io.h>
#include <trace/events/power.h>

#include "internal.h"
#include "sleep.h"

static u8 sleep_states[ACPI_S_STATE_COUNT];

static void acpi_sleep_tts_switch(u32 acpi_state)
{
        acpi_status status;

        status = acpi_execute_simple_method(NULL, "\\_TTS", acpi_state);
        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
                /*
                 * OS can't evaluate the _TTS object correctly. Some warning
                 * message will be printed. But it won't break anything.
                 */
                printk(KERN_NOTICE "Failure in evaluating _TTS object\n");
        }
}

static int tts_notify_reboot(struct notifier_block *this,
                        unsigned long code, void *x)
{
        acpi_sleep_tts_switch(ACPI_STATE_S5);
        return NOTIFY_DONE;
}

static struct notifier_block tts_notifier = {
        .notifier_call  = tts_notify_reboot,
        .next           = NULL,
        .priority       = 0,
};

static int acpi_sleep_prepare(u32 acpi_state)
{
#ifdef CONFIG_ACPI_SLEEP
        /* do we have a wakeup address for S2 and S3? */
        if (acpi_state == ACPI_STATE_S3) {
                if (!acpi_wakeup_address)
                        return -EFAULT;
                acpi_set_firmware_waking_vector(acpi_wakeup_address);

        }
        ACPI_FLUSH_CPU_CACHE();
#endif
        printk(KERN_INFO PREFIX "Preparing to enter system sleep state S%d\n",
                acpi_state);
        acpi_enable_wakeup_devices(acpi_state);
        acpi_enter_sleep_state_prep(acpi_state);
        return 0;
}

static bool acpi_sleep_state_supported(u8 sleep_state)
{
        acpi_status status;
        u8 type_a, type_b;

        status = acpi_get_sleep_type_data(sleep_state, &type_a, &type_b);
        return ACPI_SUCCESS(status) && (!acpi_gbl_reduced_hardware
                || (acpi_gbl_FADT.sleep_control.address
                        && acpi_gbl_FADT.sleep_status.address));
}

#ifdef CONFIG_ACPI_SLEEP
static u32 acpi_target_sleep_state = ACPI_STATE_S0;

u32 acpi_target_system_state(void)
{
        return acpi_target_sleep_state;
}
EXPORT_SYMBOL_GPL(acpi_target_system_state);

static bool pwr_btn_event_pending;

/*
 * The ACPI specification wants us to save NVS memory regions during hibernation
 * and to restore them during the subsequent resume.  Windows does that also for
 * suspend to RAM.  However, it is known that this mechanism does not work on
 * all machines, so we allow the user to disable it with the help of the
 * 'acpi_sleep=nonvs' kernel command line option.
 */
static bool nvs_nosave;

void __init acpi_nvs_nosave(void)
{
        nvs_nosave = true;
}

/*
 * The ACPI specification wants us to save NVS memory regions during hibernation
 * but says nothing about saving NVS during S3.  Not all versions of Windows
 * save NVS on S3 suspend either, and it is clear that not all systems need
 * NVS to be saved at S3 time.  To improve suspend/resume time, allow the
 * user to disable saving NVS on S3 if their system does not require it, but
 * continue to save/restore NVS for S4 as specified.
 */
static bool nvs_nosave_s3;

void __init acpi_nvs_nosave_s3(void)
{
        nvs_nosave_s3 = true;
}

/*
 * ACPI 1.0 wants us to execute _PTS before suspending devices, so we allow the
 * user to request that behavior by using the 'acpi_old_suspend_ordering'
 * kernel command line option that causes the following variable to be set.
 */
static bool old_suspend_ordering;

void __init acpi_old_suspend_ordering(void)
{
        old_suspend_ordering = true;
}

static int __init init_old_suspend_ordering(const struct dmi_system_id *d)
{
        acpi_old_suspend_ordering();
        return 0;
}

static int __init init_nvs_nosave(const struct dmi_system_id *d)
{
        acpi_nvs_nosave();
        return 0;
}

static struct dmi_system_id acpisleep_dmi_table[] __initdata = {
        {
        .callback = init_old_suspend_ordering,
        .ident = "Abit KN9 (nForce4 variant)",
        .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "http://www.abit.com.tw/"),
                DMI_MATCH(DMI_BOARD_NAME, "KN9 Series(NF-CK804)"),
                },
        },
        {
        .callback = init_old_suspend_ordering,
        .ident = "HP xw4600 Workstation",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
                DMI_MATCH(DMI_PRODUCT_NAME, "HP xw4600 Workstation"),
                },
        },
        {
        .callback = init_old_suspend_ordering,
        .ident = "Asus Pundit P1-AH2 (M2N8L motherboard)",
        .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTek Computer INC."),
                DMI_MATCH(DMI_BOARD_NAME, "M2N8L"),
                },
        },
        {
        .callback = init_old_suspend_ordering,
        .ident = "Panasonic CF51-2L",
        .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR,
                                "Matsushita Electric Industrial Co.,Ltd."),
                DMI_MATCH(DMI_BOARD_NAME, "CF51-2L"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-FW41E_H",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW41E_H"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-FW21E",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21E"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-FW21M",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW21M"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VPCEB17FX",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB17FX"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-SR11M",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR11M"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Everex StepNote Series",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Everex Systems, Inc."),
                DMI_MATCH(DMI_PRODUCT_NAME, "Everex StepNote Series"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VPCEB1Z1E",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1Z1E"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-NW130D",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-NW130D"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VPCCW29FX",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VPCCW29FX"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Averatec AV1020-ED2",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "AVERATEC"),
                DMI_MATCH(DMI_PRODUCT_NAME, "1000 Series"),
                },
        },
        {
        .callback = init_old_suspend_ordering,
        .ident = "Asus A8N-SLI DELUXE",
        .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI DELUXE"),
                },
        },
        {
        .callback = init_old_suspend_ordering,
        .ident = "Asus A8N-SLI Premium",
        .matches = {
                DMI_MATCH(DMI_BOARD_VENDOR, "ASUSTeK Computer INC."),
                DMI_MATCH(DMI_BOARD_NAME, "A8N-SLI Premium"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-SR26GN_P",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-SR26GN_P"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VPCEB1S1E",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VPCEB1S1E"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Sony Vaio VGN-FW520F",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "Sony Corporation"),
                DMI_MATCH(DMI_PRODUCT_NAME, "VGN-FW520F"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Asus K54C",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
                DMI_MATCH(DMI_PRODUCT_NAME, "K54C"),
                },
        },
        {
        .callback = init_nvs_nosave,
        .ident = "Asus K54HR",
        .matches = {
                DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
                DMI_MATCH(DMI_PRODUCT_NAME, "K54HR"),
                },
        },
        {},
};

static void __init acpi_sleep_dmi_check(void)
{
        int year;

        if (dmi_get_date(DMI_BIOS_DATE, &year, NULL, NULL) && year >= 2012)
                acpi_nvs_nosave_s3();

        dmi_check_system(acpisleep_dmi_table);
}

/**
 * acpi_pm_freeze - Disable the GPEs and suspend EC transactions.
 */
static int acpi_pm_freeze(void)
{
        acpi_disable_all_gpes();
        acpi_os_wait_events_complete();
        acpi_ec_block_transactions();
        return 0;
}

/**
 * acpi_pre_suspend - Enable wakeup devices, "freeze" EC and save NVS.
 */
static int acpi_pm_pre_suspend(void)
{
        acpi_pm_freeze();
        return suspend_nvs_save();
}

/**
 *      __acpi_pm_prepare - Prepare the platform to enter the target state.
 *
 *      If necessary, set the firmware waking vector and do arch-specific
 *      nastiness to get the wakeup code to the waking vector.
 */
static int __acpi_pm_prepare(void)
{
        int error = acpi_sleep_prepare(acpi_target_sleep_state);
        if (error)
                acpi_target_sleep_state = ACPI_STATE_S0;

        return error;
}

/**
 *      acpi_pm_prepare - Prepare the platform to enter the target sleep
 *              state and disable the GPEs.
 */
static int acpi_pm_prepare(void)
{
        int error = __acpi_pm_prepare();
        if (!error)
                error = acpi_pm_pre_suspend();

        return error;
}

static int find_powerf_dev(struct device *dev, void *data)
{
        struct acpi_device *device = to_acpi_device(dev);
        const char *hid = acpi_device_hid(device);

        return !strcmp(hid, ACPI_BUTTON_HID_POWERF);
}

/**
 *      acpi_pm_finish - Instruct the platform to leave a sleep state.
 *
 *      This is called after we wake back up (or if entering the sleep state
 *      failed).
 */
static void acpi_pm_finish(void)
{
        struct device *pwr_btn_dev;
        u32 acpi_state = acpi_target_sleep_state;

        acpi_ec_unblock_transactions();
        suspend_nvs_free();

        if (acpi_state == ACPI_STATE_S0)
                return;

        printk(KERN_INFO PREFIX "Waking up from system sleep state S%d\n",
                acpi_state);
        acpi_disable_wakeup_devices(acpi_state);
        acpi_leave_sleep_state(acpi_state);

        /* reset firmware waking vector */
        acpi_set_firmware_waking_vector((acpi_physical_address) 0);

        acpi_target_sleep_state = ACPI_STATE_S0;

        acpi_resume_power_resources();

        /* If we were woken with the fixed power button, provide a small
         * hint to userspace in the form of a wakeup event on the fixed power
         * button device (if it can be found).
         *
         * We delay the event generation til now, as the PM layer requires
         * timekeeping to be running before we generate events. */
        if (!pwr_btn_event_pending)
                return;

        pwr_btn_event_pending = false;
        pwr_btn_dev = bus_find_device(&acpi_bus_type, NULL, NULL,
                                      find_powerf_dev);
        if (pwr_btn_dev) {
                pm_wakeup_event(pwr_btn_dev, 0);
                put_device(pwr_btn_dev);
        }
}

/**
 * acpi_pm_start - Start system PM transition.
 */
static void acpi_pm_start(u32 acpi_state)
{
        acpi_target_sleep_state = acpi_state;
        acpi_sleep_tts_switch(acpi_target_sleep_state);
        acpi_scan_lock_acquire();
}

/**
 * acpi_pm_end - Finish up system PM transition.
 */
static void acpi_pm_end(void)
{
        acpi_scan_lock_release();
        /*
         * This is necessary in case acpi_pm_finish() is not called during a
         * failing transition to a sleep state.
         */
        acpi_target_sleep_state = ACPI_STATE_S0;
        acpi_sleep_tts_switch(acpi_target_sleep_state);
}
#else /* !CONFIG_ACPI_SLEEP */
#define acpi_target_sleep_state ACPI_STATE_S0
static inline void acpi_sleep_dmi_check(void) {}
#endif /* CONFIG_ACPI_SLEEP */

#ifdef CONFIG_SUSPEND
static u32 acpi_suspend_states[] = {
        [PM_SUSPEND_ON] = ACPI_STATE_S0,
        [PM_SUSPEND_STANDBY] = ACPI_STATE_S1,
        [PM_SUSPEND_MEM] = ACPI_STATE_S3,
        [PM_SUSPEND_MAX] = ACPI_STATE_S5
};

/**
 *      acpi_suspend_begin - Set the target system sleep state to the state
 *              associated with given @pm_state, if supported.
 */
static int acpi_suspend_begin(suspend_state_t pm_state)
{
        u32 acpi_state = acpi_suspend_states[pm_state];
        int error;

        error = (nvs_nosave || nvs_nosave_s3) ? 0 : suspend_nvs_alloc();
        if (error)
                return error;

        if (!sleep_states[acpi_state]) {
                pr_err("ACPI does not support sleep state S%u\n", acpi_state);
                return -ENOSYS;
        }

        acpi_pm_start(acpi_state);
        return 0;
}

/**
 *      acpi_suspend_enter - Actually enter a sleep state.
 *      @pm_state: ignored
 *
 *      Flush caches and go to sleep. For STR we have to call arch-specific
 *      assembly, which in turn call acpi_enter_sleep_state().
 *      It's unfortunate, but it works. Please fix if you're feeling frisky.
 */
static int acpi_suspend_enter(suspend_state_t pm_state)
{
        acpi_status status = AE_OK;
        u32 acpi_state = acpi_target_sleep_state;
        int error;

        ACPI_FLUSH_CPU_CACHE();

        trace_suspend_resume(TPS("acpi_suspend"), acpi_state, true);
        switch (acpi_state) {
        case ACPI_STATE_S1:
                barrier();
                status = acpi_enter_sleep_state(acpi_state);
                break;

        case ACPI_STATE_S3:
                if (!acpi_suspend_lowlevel)
                        return -ENOSYS;
                error = acpi_suspend_lowlevel();
                if (error)
                        return error;
                pr_info(PREFIX "Low-level resume complete\n");
                break;
        }
        trace_suspend_resume(TPS("acpi_suspend"), acpi_state, false);

        /* This violates the spec but is required for bug compatibility. */
        acpi_write_bit_register(ACPI_BITREG_SCI_ENABLE, 1);

        /* Reprogram control registers */
        acpi_leave_sleep_state_prep(acpi_state);

        /* ACPI 3.0 specs (P62) says that it's the responsibility
         * of the OSPM to clear the status bit [ implying that the
         * POWER_BUTTON event should not reach userspace ]
         *
         * However, we do generate a small hint for userspace in the form of
         * a wakeup event. We flag this condition for now and generate the
         * event later, as we're currently too early in resume to be able to
         * generate wakeup events.
         */
        if (ACPI_SUCCESS(status) && (acpi_state == ACPI_STATE_S3)) {
                acpi_event_status pwr_btn_status = ACPI_EVENT_FLAG_DISABLED;

                acpi_get_event_status(ACPI_EVENT_POWER_BUTTON, &pwr_btn_status);

                if (pwr_btn_status & ACPI_EVENT_FLAG_SET) {
                        acpi_clear_event(ACPI_EVENT_POWER_BUTTON);
                        /* Flag for later */
                        pwr_btn_event_pending = true;
                }
        }

        /*
         * Disable and clear GPE status before interrupt is enabled. Some GPEs
         * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
         * acpi_leave_sleep_state will reenable specific GPEs later
         */
        acpi_disable_all_gpes();
        /* Allow EC transactions to happen. */
        acpi_ec_unblock_transactions_early();

        suspend_nvs_restore();

        return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}

static int acpi_suspend_state_valid(suspend_state_t pm_state)
{
        u32 acpi_state;

        switch (pm_state) {
        case PM_SUSPEND_ON:
        case PM_SUSPEND_STANDBY:
        case PM_SUSPEND_MEM:
                acpi_state = acpi_suspend_states[pm_state];

                return sleep_states[acpi_state];
        default:
                return 0;
        }
}

static const struct platform_suspend_ops acpi_suspend_ops = {
        .valid = acpi_suspend_state_valid,
        .begin = acpi_suspend_begin,
        .prepare_late = acpi_pm_prepare,
        .enter = acpi_suspend_enter,
        .wake = acpi_pm_finish,
        .end = acpi_pm_end,
};

/**
 *      acpi_suspend_begin_old - Set the target system sleep state to the
 *              state associated with given @pm_state, if supported, and
 *              execute the _PTS control method.  This function is used if the
 *              pre-ACPI 2.0 suspend ordering has been requested.
 */
static int acpi_suspend_begin_old(suspend_state_t pm_state)
{
        int error = acpi_suspend_begin(pm_state);
        if (!error)
                error = __acpi_pm_prepare();

        return error;
}

/*
 * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
 * been requested.
 */
static const struct platform_suspend_ops acpi_suspend_ops_old = {
        .valid = acpi_suspend_state_valid,
        .begin = acpi_suspend_begin_old,
        .prepare_late = acpi_pm_pre_suspend,
        .enter = acpi_suspend_enter,
        .wake = acpi_pm_finish,
        .end = acpi_pm_end,
        .recover = acpi_pm_finish,
};

static int acpi_freeze_begin(void)
{
        acpi_scan_lock_acquire();
        return 0;
}

static int acpi_freeze_prepare(void)
{
        acpi_enable_wakeup_devices(ACPI_STATE_S0);
        acpi_enable_all_wakeup_gpes();
        acpi_os_wait_events_complete();
        enable_irq_wake(acpi_gbl_FADT.sci_interrupt);
        return 0;
}

static void acpi_freeze_restore(void)
{
        acpi_disable_wakeup_devices(ACPI_STATE_S0);
        disable_irq_wake(acpi_gbl_FADT.sci_interrupt);
        acpi_enable_all_runtime_gpes();
}

static void acpi_freeze_end(void)
{
        acpi_scan_lock_release();
}

static const struct platform_freeze_ops acpi_freeze_ops = {
        .begin = acpi_freeze_begin,
        .prepare = acpi_freeze_prepare,
        .restore = acpi_freeze_restore,
        .end = acpi_freeze_end,
};

static void acpi_sleep_suspend_setup(void)
{
        int i;

        for (i = ACPI_STATE_S1; i < ACPI_STATE_S4; i++)
                if (acpi_sleep_state_supported(i))
                        sleep_states[i] = 1;

        suspend_set_ops(old_suspend_ordering ?
                &acpi_suspend_ops_old : &acpi_suspend_ops);
        freeze_set_ops(&acpi_freeze_ops);
}

#else /* !CONFIG_SUSPEND */
static inline void acpi_sleep_suspend_setup(void) {}
#endif /* !CONFIG_SUSPEND */

#ifdef CONFIG_HIBERNATION
static unsigned long s4_hardware_signature;
static struct acpi_table_facs *facs;
static bool nosigcheck;

void __init acpi_no_s4_hw_signature(void)
{
        nosigcheck = true;
}

static int acpi_hibernation_begin(void)
{
        int error;

        error = nvs_nosave ? 0 : suspend_nvs_alloc();
        if (!error)
                acpi_pm_start(ACPI_STATE_S4);

        return error;
}

static int acpi_hibernation_enter(void)
{
        acpi_status status = AE_OK;

        ACPI_FLUSH_CPU_CACHE();

        /* This shouldn't return.  If it returns, we have a problem */
        status = acpi_enter_sleep_state(ACPI_STATE_S4);
        /* Reprogram control registers */
        acpi_leave_sleep_state_prep(ACPI_STATE_S4);

        return ACPI_SUCCESS(status) ? 0 : -EFAULT;
}

static void acpi_hibernation_leave(void)
{
        /*
         * If ACPI is not enabled by the BIOS and the boot kernel, we need to
         * enable it here.
         */
        acpi_enable();
        /* Reprogram control registers */
        acpi_leave_sleep_state_prep(ACPI_STATE_S4);
        /* Check the hardware signature */
        if (facs && s4_hardware_signature != facs->hardware_signature)
                pr_crit("ACPI: Hardware changed while hibernated, success doubtful!\n");
        /* Restore the NVS memory area */
        suspend_nvs_restore();
        /* Allow EC transactions to happen. */
        acpi_ec_unblock_transactions_early();
}

static void acpi_pm_thaw(void)
{
        acpi_ec_unblock_transactions();
        acpi_enable_all_runtime_gpes();
}

static const struct platform_hibernation_ops acpi_hibernation_ops = {
        .begin = acpi_hibernation_begin,
        .end = acpi_pm_end,
        .pre_snapshot = acpi_pm_prepare,
        .finish = acpi_pm_finish,
        .prepare = acpi_pm_prepare,
        .enter = acpi_hibernation_enter,
        .leave = acpi_hibernation_leave,
        .pre_restore = acpi_pm_freeze,
        .restore_cleanup = acpi_pm_thaw,
};

/**
 *      acpi_hibernation_begin_old - Set the target system sleep state to
 *              ACPI_STATE_S4 and execute the _PTS control method.  This
 *              function is used if the pre-ACPI 2.0 suspend ordering has been
 *              requested.
 */
static int acpi_hibernation_begin_old(void)
{
        int error;
        /*
         * The _TTS object should always be evaluated before the _PTS object.
         * When the old_suspended_ordering is true, the _PTS object is
         * evaluated in the acpi_sleep_prepare.
         */
        acpi_sleep_tts_switch(ACPI_STATE_S4);

        error = acpi_sleep_prepare(ACPI_STATE_S4);

        if (!error) {
                if (!nvs_nosave)
                        error = suspend_nvs_alloc();
                if (!error) {
                        acpi_target_sleep_state = ACPI_STATE_S4;
                        acpi_scan_lock_acquire();
                }
        }
        return error;
}

/*
 * The following callbacks are used if the pre-ACPI 2.0 suspend ordering has
 * been requested.
 */
static const struct platform_hibernation_ops acpi_hibernation_ops_old = {
        .begin = acpi_hibernation_begin_old,
        .end = acpi_pm_end,
        .pre_snapshot = acpi_pm_pre_suspend,
        .prepare = acpi_pm_freeze,
        .finish = acpi_pm_finish,
        .enter = acpi_hibernation_enter,
        .leave = acpi_hibernation_leave,
        .pre_restore = acpi_pm_freeze,
        .restore_cleanup = acpi_pm_thaw,
        .recover = acpi_pm_finish,
};

static void acpi_sleep_hibernate_setup(void)
{
        if (!acpi_sleep_state_supported(ACPI_STATE_S4))
                return;

        hibernation_set_ops(old_suspend_ordering ?
                        &acpi_hibernation_ops_old : &acpi_hibernation_ops);
        sleep_states[ACPI_STATE_S4] = 1;
        if (nosigcheck)
                return;

        acpi_get_table(ACPI_SIG_FACS, 1, (struct acpi_table_header **)&facs);
        if (facs)
                s4_hardware_signature = facs->hardware_signature;
}
#else /* !CONFIG_HIBERNATION */
static inline void acpi_sleep_hibernate_setup(void) {}
#endif /* !CONFIG_HIBERNATION */

static void acpi_power_off_prepare(void)
{
        /* Prepare to power off the system */
        acpi_sleep_prepare(ACPI_STATE_S5);
        acpi_disable_all_gpes();
        acpi_os_wait_events_complete();
}

static void acpi_power_off(void)
{
        /* acpi_sleep_prepare(ACPI_STATE_S5) should have already been called */
        printk(KERN_DEBUG "%s called\n", __func__);
        local_irq_disable();
        acpi_enter_sleep_state(ACPI_STATE_S5);
}

int __init acpi_sleep_init(void)
{
        char supported[ACPI_S_STATE_COUNT * 3 + 1];
        char *pos = supported;
        int i;

        acpi_sleep_dmi_check();

        sleep_states[ACPI_STATE_S0] = 1;

        acpi_sleep_suspend_setup();
        acpi_sleep_hibernate_setup();

        if (acpi_sleep_state_supported(ACPI_STATE_S5)) {
                sleep_states[ACPI_STATE_S5] = 1;
                pm_power_off_prepare = acpi_power_off_prepare;
                pm_power_off = acpi_power_off;
        }

        supported[0] = 0;
        for (i = 0; i < ACPI_S_STATE_COUNT; i++) {
                if (sleep_states[i])
                        pos += sprintf(pos, " S%d", i);
        }
        pr_info(PREFIX "(supports%s)\n", supported);

        /*
         * Register the tts_notifier to reboot notifier list so that the _TTS
         * object can also be evaluated when the system enters S5.
         */
        register_reboot_notifier(&tts_notifier);
        return 0;
}