text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * 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
   */
  
  #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 <linux/syscore_ops.h>
  #include <asm/io.h>
  #include <trace/events/power.h>
  
  #include "internal.h"
  #include "sleep.h"
  
  /*
   * Some HW-full platforms do not have _S5, so they may need
   * to leverage efi power off for a shutdown.
   */
  bool acpi_no_s5;
  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_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;
  }
  
  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 bool sleep_no_lps0 __read_mostly;
  module_param(sleep_no_lps0, bool, 0644);
  MODULE_PARM_DESC(sleep_no_lps0, "Do not use the special LPS0 device interface");
  
  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;
  }
  
  static int __init init_nvs_save_s3(const struct dmi_system_id *d)
  {
  	nvs_nosave_s3 = false;
  	return 0;
  }
  
  /*
   * 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 bool acpi_sleep_default_s3;
  
  static int __init init_default_s3(const struct dmi_system_id *d)
  {
  	acpi_sleep_default_s3 = true;
  	return 0;
  }
  
  static const struct dmi_system_id acpisleep_dmi_table[] __initconst = {
  	{
  	.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"),
  		},
  	},
  	{
  	.callback = init_nvs_save_s3,
  	.ident = "Asus 1025C",
  	.matches = {
  		DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK COMPUTER INC."),
  		DMI_MATCH(DMI_PRODUCT_NAME, "1025C"),
  		},
  	},
  	/*
  	 * https://bugzilla.kernel.org/show_bug.cgi?id=189431
  	 * Lenovo G50-45 is a platform later than 2012, but needs nvs memory
  	 * saving during S3.
  	 */
  	{
  	.callback = init_nvs_save_s3,
  	.ident = "Lenovo G50-45",
  	.matches = {
  		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
  		DMI_MATCH(DMI_PRODUCT_NAME, "80E3"),
  		},
  	},
  	/*
  	 * ThinkPad X1 Tablet(2016) cannot do suspend-to-idle using
  	 * the Low Power S0 Idle firmware interface (see
  	 * https://bugzilla.kernel.org/show_bug.cgi?id=199057).
  	 */
  	{
  	.callback = init_default_s3,
  	.ident = "ThinkPad X1 Tablet(2016)",
  	.matches = {
  		DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
  		DMI_MATCH(DMI_PRODUCT_NAME, "20GGA00L00"),
  		},
  	},
  	{},
  };
  
  static bool ignore_blacklist;
  
  void __init acpi_sleep_no_blacklist(void)
  {
  	ignore_blacklist = true;
  }
  
  static void __init acpi_sleep_dmi_check(void)
  {
  	if (ignore_blacklist)
  		return;
  
  	if (dmi_get_bios_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;
  }
  
  /**
   *	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 acpi_device *pwr_btn_adev;
  	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_waking_vector(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_adev = acpi_dev_get_first_match_dev(ACPI_BUTTON_HID_POWERF,
  						    NULL, -1);
  	if (pwr_btn_adev) {
  		pm_wakeup_event(&pwr_btn_adev->dev, 0);
  		acpi_dev_put(pwr_btn_adev);
  	}
  }
  
  /**
   * 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_turn_off_unused_power_resources();
  	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 sleep_no_lps0	(1)
  #define acpi_target_sleep_state	ACPI_STATE_S0
  #define acpi_sleep_default_s3	(1)
  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;
  	}
  	if (acpi_state > ACPI_STATE_S1)
  		pm_set_suspend_via_firmware();
  
  	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");
  		pm_set_resume_via_firmware();
  		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_STATUS_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();
  
  	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 bool s2idle_wakeup;
  
  /*
   * On platforms supporting the Low Power S0 Idle interface there is an ACPI
   * device object with the PNP0D80 compatible device ID (System Power Management
   * Controller) and a specific _DSM method under it.  That method, if present,
   * can be used to indicate to the platform that the OS is transitioning into a
   * low-power state in which certain types of activity are not desirable or that
   * it is leaving such a state, which allows the platform to adjust its operation
   * mode accordingly.
   */
  static const struct acpi_device_id lps0_device_ids[] = {
  	{"PNP0D80", },
  	{"", },
  };
  
  #define ACPI_LPS0_DSM_UUID	"c4eb40a0-6cd2-11e2-bcfd-0800200c9a66"
  
  #define ACPI_LPS0_GET_DEVICE_CONSTRAINTS	1
  #define ACPI_LPS0_SCREEN_OFF	3
  #define ACPI_LPS0_SCREEN_ON	4
  #define ACPI_LPS0_ENTRY		5
  #define ACPI_LPS0_EXIT		6
  
  static acpi_handle lps0_device_handle;
  static guid_t lps0_dsm_guid;
  static char lps0_dsm_func_mask;
  
  /* Device constraint entry structure */
  struct lpi_device_info {
  	char *name;
  	int enabled;
  	union acpi_object *package;
  };
  
  /* Constraint package structure */
  struct lpi_device_constraint {
  	int uid;
  	int min_dstate;
  	int function_states;
  };
  
  struct lpi_constraints {
  	acpi_handle handle;
  	int min_dstate;
  };
  
  static struct lpi_constraints *lpi_constraints_table;
  static int lpi_constraints_table_size;
  
  static void lpi_device_get_constraints(void)
  {
  	union acpi_object *out_obj;
  	int i;
  
  	out_obj = acpi_evaluate_dsm_typed(lps0_device_handle, &lps0_dsm_guid,
  					  1, ACPI_LPS0_GET_DEVICE_CONSTRAINTS,
  					  NULL, ACPI_TYPE_PACKAGE);
  
  	acpi_handle_debug(lps0_device_handle, "_DSM function 1 eval %s\n",
  			  out_obj ? "successful" : "failed");
  
  	if (!out_obj)
  		return;
  
  	lpi_constraints_table = kcalloc(out_obj->package.count,
  					sizeof(*lpi_constraints_table),
  					GFP_KERNEL);
  	if (!lpi_constraints_table)
  		goto free_acpi_buffer;
  
  	acpi_handle_debug(lps0_device_handle, "LPI: constraints list begin:\n");
  
  	for (i = 0; i < out_obj->package.count; i++) {
  		struct lpi_constraints *constraint;
  		acpi_status status;
  		union acpi_object *package = &out_obj->package.elements[i];
  		struct lpi_device_info info = { };
  		int package_count = 0, j;
  
  		if (!package)
  			continue;
  
  		for (j = 0; j < package->package.count; ++j) {
  			union acpi_object *element =
  					&(package->package.elements[j]);
  
  			switch (element->type) {
  			case ACPI_TYPE_INTEGER:
  				info.enabled = element->integer.value;
  				break;
  			case ACPI_TYPE_STRING:
  				info.name = element->string.pointer;
  				break;
  			case ACPI_TYPE_PACKAGE:
  				package_count = element->package.count;
  				info.package = element->package.elements;
  				break;
  			}
  		}
  
  		if (!info.enabled || !info.package || !info.name)
  			continue;
  
  		constraint = &lpi_constraints_table[lpi_constraints_table_size];
  
  		status = acpi_get_handle(NULL, info.name, &constraint->handle);
  		if (ACPI_FAILURE(status))
  			continue;
  
  		acpi_handle_debug(lps0_device_handle,
  				  "index:%d Name:%s\n", i, info.name);
  
  		constraint->min_dstate = -1;
  
  		for (j = 0; j < package_count; ++j) {
  			union acpi_object *info_obj = &info.package[j];
  			union acpi_object *cnstr_pkg;
  			union acpi_object *obj;
  			struct lpi_device_constraint dev_info;
  
  			switch (info_obj->type) {
  			case ACPI_TYPE_INTEGER:
  				/* version */
  				break;
  			case ACPI_TYPE_PACKAGE:
  				if (info_obj->package.count < 2)
  					break;
  
  				cnstr_pkg = info_obj->package.elements;
  				obj = &cnstr_pkg[0];
  				dev_info.uid = obj->integer.value;
  				obj = &cnstr_pkg[1];
  				dev_info.min_dstate = obj->integer.value;
  
  				acpi_handle_debug(lps0_device_handle,
  					"uid:%d min_dstate:%s\n",
  					dev_info.uid,
  					acpi_power_state_string(dev_info.min_dstate));
  
  				constraint->min_dstate = dev_info.min_dstate;
  				break;
  			}
  		}
  
  		if (constraint->min_dstate < 0) {
  			acpi_handle_debug(lps0_device_handle,
  					  "Incomplete constraint defined\n");
  			continue;
  		}
  
  		lpi_constraints_table_size++;
  	}
  
  	acpi_handle_debug(lps0_device_handle, "LPI: constraints list end\n");
  
  free_acpi_buffer:
  	ACPI_FREE(out_obj);
  }
  
  static void lpi_check_constraints(void)
  {
  	int i;
  
  	for (i = 0; i < lpi_constraints_table_size; ++i) {
  		acpi_handle handle = lpi_constraints_table[i].handle;
  		struct acpi_device *adev;
  
  		if (!handle || acpi_bus_get_device(handle, &adev))
  			continue;
  
  		acpi_handle_debug(handle,
  			"LPI: required min power state:%s current power state:%s\n",
  			acpi_power_state_string(lpi_constraints_table[i].min_dstate),
  			acpi_power_state_string(adev->power.state));
  
  		if (!adev->flags.power_manageable) {
  			acpi_handle_info(handle, "LPI: Device not power manageable\n");
  			lpi_constraints_table[i].handle = NULL;
  			continue;
  		}
  
  		if (adev->power.state < lpi_constraints_table[i].min_dstate)
  			acpi_handle_info(handle,
  				"LPI: Constraint not met; min power state:%s current power state:%s\n",
  				acpi_power_state_string(lpi_constraints_table[i].min_dstate),
  				acpi_power_state_string(adev->power.state));
  	}
  }
  
  static void acpi_sleep_run_lps0_dsm(unsigned int func)
  {
  	union acpi_object *out_obj;
  
  	if (!(lps0_dsm_func_mask & (1 << func)))
  		return;
  
  	out_obj = acpi_evaluate_dsm(lps0_device_handle, &lps0_dsm_guid, 1, func, NULL);
  	ACPI_FREE(out_obj);
  
  	acpi_handle_debug(lps0_device_handle, "_DSM function %u evaluation %s\n",
  			  func, out_obj ? "successful" : "failed");
  }
  
  static int lps0_device_attach(struct acpi_device *adev,
  			      const struct acpi_device_id *not_used)
  {
  	union acpi_object *out_obj;
  
  	if (lps0_device_handle)
  		return 0;
  
  	if (!(acpi_gbl_FADT.flags & ACPI_FADT_LOW_POWER_S0))
  		return 0;
  
  	guid_parse(ACPI_LPS0_DSM_UUID, &lps0_dsm_guid);
  	/* Check if the _DSM is present and as expected. */
  	out_obj = acpi_evaluate_dsm(adev->handle, &lps0_dsm_guid, 1, 0, NULL);
  	if (!out_obj || out_obj->type != ACPI_TYPE_BUFFER) {
  		acpi_handle_debug(adev->handle,
  				  "_DSM function 0 evaluation failed\n");
  		return 0;
  	}
  
  	lps0_dsm_func_mask = *(char *)out_obj->buffer.pointer;
  
  	ACPI_FREE(out_obj);
  
  	acpi_handle_debug(adev->handle, "_DSM function mask: 0x%x\n",
  			  lps0_dsm_func_mask);
  
  	lps0_device_handle = adev->handle;
  
  	lpi_device_get_constraints();
  
  	/*
  	 * Use suspend-to-idle by default if the default suspend mode was not
  	 * set from the command line.
  	 */
  	if (mem_sleep_default > PM_SUSPEND_MEM && !acpi_sleep_default_s3)
  		mem_sleep_current = PM_SUSPEND_TO_IDLE;
  
  	/*
  	 * Some LPS0 systems, like ASUS Zenbook UX430UNR/i7-8550U, require the
  	 * EC GPE to be enabled while suspended for certain wakeup devices to
  	 * work, so mark it as wakeup-capable.
  	 */
  	acpi_ec_mark_gpe_for_wake();
  
  	return 0;
  }
  
  static struct acpi_scan_handler lps0_handler = {
  	.ids = lps0_device_ids,
  	.attach = lps0_device_attach,
  };
  
  static int acpi_s2idle_begin(void)
  {
  	acpi_scan_lock_acquire();
  	return 0;
  }
  
  static int acpi_s2idle_prepare(void)
  {
  	if (acpi_sci_irq_valid()) {
  		enable_irq_wake(acpi_sci_irq);
  		acpi_ec_set_gpe_wake_mask(ACPI_GPE_ENABLE);
  	}
  
  	acpi_enable_wakeup_devices(ACPI_STATE_S0);
  
  	/* Change the configuration of GPEs to avoid spurious wakeup. */
  	acpi_enable_all_wakeup_gpes();
  	acpi_os_wait_events_complete();
  
  	s2idle_wakeup = true;
  	return 0;
  }
  
  static int acpi_s2idle_prepare_late(void)
  {
  	if (!lps0_device_handle || sleep_no_lps0)
  		return 0;
  
  	if (pm_debug_messages_on)
  		lpi_check_constraints();
  
  	acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_OFF);
  	acpi_sleep_run_lps0_dsm(ACPI_LPS0_ENTRY);
  
  	return 0;
  }
  
  static bool acpi_s2idle_wake(void)
  {
  	if (!acpi_sci_irq_valid())
  		return pm_wakeup_pending();
  
  	while (pm_wakeup_pending()) {
  		/*
  		 * If IRQD_WAKEUP_ARMED is set for the SCI at this point, the
  		 * SCI has not triggered while suspended, so bail out (the
  		 * wakeup is pending anyway and the SCI is not the source of
  		 * it).
  		 */
  		if (irqd_is_wakeup_armed(irq_get_irq_data(acpi_sci_irq)))
  			return true;
  
  		/*
  		 * If the status bit of any enabled fixed event is set, the
  		 * wakeup is regarded as valid.
  		 */
  		if (acpi_any_fixed_event_status_set())
  			return true;
  
  		/* Check wakeups from drivers sharing the SCI. */
  		if (acpi_check_wakeup_handlers())
  			return true;
  
  		/* Check non-EC GPE wakeups and dispatch the EC GPE. */
  		if (acpi_ec_dispatch_gpe())
  			return true;
  
  		/*
  		 * Cancel the SCI wakeup and process all pending events in case
  		 * there are any wakeup ones in there.
  		 *
  		 * Note that if any non-EC GPEs are active at this point, the
  		 * SCI will retrigger after the rearming below, so no events
  		 * should be missed by canceling the wakeup here.
  		 */
  		pm_system_cancel_wakeup();
  		acpi_os_wait_events_complete();
  
  		/*
  		 * The SCI is in the "suspended" state now and it cannot produce
  		 * new wakeup events till the rearming below, so if any of them
  		 * are pending here, they must be resulting from the processing
  		 * of EC events above or coming from somewhere else.
  		 */
  		if (pm_wakeup_pending())
  			return true;
  
  		rearm_wake_irq(acpi_sci_irq);
  	}
  
  	return false;
  }
  
  static void acpi_s2idle_restore_early(void)
  {
  	if (!lps0_device_handle || sleep_no_lps0)
  		return;
  
  	acpi_sleep_run_lps0_dsm(ACPI_LPS0_EXIT);
  	acpi_sleep_run_lps0_dsm(ACPI_LPS0_SCREEN_ON);
  }
  
  static void acpi_s2idle_restore(void)
  {
  	/*
  	 * Drain pending events before restoring the working-state configuration
  	 * of GPEs.
  	 */
  	acpi_os_wait_events_complete(); /* synchronize GPE processing */
  	acpi_ec_flush_work(); /* flush the EC driver's workqueues */
  	acpi_os_wait_events_complete(); /* synchronize Notify handling */
  
  	s2idle_wakeup = false;
  
  	acpi_enable_all_runtime_gpes();
  
  	acpi_disable_wakeup_devices(ACPI_STATE_S0);
  
  	if (acpi_sci_irq_valid()) {
  		acpi_ec_set_gpe_wake_mask(ACPI_GPE_DISABLE);
  		disable_irq_wake(acpi_sci_irq);
  	}
  }
  
  static void acpi_s2idle_end(void)
  {
  	acpi_scan_lock_release();
  }
  
  static const struct platform_s2idle_ops acpi_s2idle_ops = {
  	.begin = acpi_s2idle_begin,
  	.prepare = acpi_s2idle_prepare,
  	.prepare_late = acpi_s2idle_prepare_late,
  	.wake = acpi_s2idle_wake,
  	.restore_early = acpi_s2idle_restore_early,
  	.restore = acpi_s2idle_restore,
  	.end = acpi_s2idle_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);
  
  	acpi_scan_add_handler(&lps0_handler);
  	s2idle_set_ops(&acpi_s2idle_ops);
  }
  
  #else /* !CONFIG_SUSPEND */
  #define s2idle_wakeup		(false)
  #define lps0_device_handle	(NULL)
  static inline void acpi_sleep_suspend_setup(void) {}
  #endif /* !CONFIG_SUSPEND */
  
  bool acpi_s2idle_wakeup(void)
  {
  	return s2idle_wakeup;
  }
  
  #ifdef CONFIG_PM_SLEEP
  static u32 saved_bm_rld;
  
  static int  acpi_save_bm_rld(void)
  {
  	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &saved_bm_rld);
  	return 0;
  }
  
  static void  acpi_restore_bm_rld(void)
  {
  	u32 resumed_bm_rld = 0;
  
  	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_RLD, &resumed_bm_rld);
  	if (resumed_bm_rld == saved_bm_rld)
  		return;
  
  	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, saved_bm_rld);
  }
  
  static struct syscore_ops acpi_sleep_syscore_ops = {
  	.suspend = acpi_save_bm_rld,
  	.resume = acpi_restore_bm_rld,
  };
  
  static void acpi_sleep_syscore_init(void)
  {
  	register_syscore_ops(&acpi_sleep_syscore_ops);
  }
  #else
  static inline void acpi_sleep_syscore_init(void) {}
  #endif /* CONFIG_PM_SLEEP */
  
  #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(pm_message_t stage)
  {
  	if (!nvs_nosave) {
  		int error = suspend_nvs_alloc();
  		if (error)
  			return error;
  	}
  
  	if (stage.event == PM_EVENT_HIBERNATE)
  		pm_set_suspend_via_firmware();
  
  	acpi_pm_start(ACPI_STATE_S4);
  	return 0;
  }
  
  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)
  {
  	pm_set_resume_via_firmware();
  	/*
  	 * 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();
  }
  
  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(pm_message_t stage)
  {
  	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)
  		return error;
  
  	if (!nvs_nosave) {
  		error = suspend_nvs_alloc();
  		if (error)
  			return error;
  	}
  
  	if (stage.event == PM_EVENT_HIBERNATE)
  		pm_set_suspend_via_firmware();
  
  	acpi_target_sleep_state = ACPI_STATE_S4;
  	acpi_scan_lock_acquire();
  	return 0;
  }
  
  /*
   * 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_syscore_init();
  	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;
  	} else {
  		acpi_no_s5 = true;
  	}
  
  	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;
  }
  