// SPDX-License-Identifier: GPL-2.0-or-later

  /*
   * processor_idle - idle state submodule to the ACPI processor driver
   *
   *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>

   *  Copyright (C) 2004, 2005 Dominik Brodowski <linux@brodo.de>

   *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
   *  			- Added processor hotplug support

   *  Copyright (C) 2005  Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
   *  			- Added support for C3 on SMP

   */

  #define pr_fmt(fmt) "ACPI: " fmt

  #include <linux/module.h>

  #include <linux/acpi.h>
  #include <linux/dmi.h>

  #include <linux/sched.h>       /* need_resched() */

  #include <linux/tick.h>

  #include <linux/cpuidle.h>

  #include <linux/cpu.h>

  #include <acpi/processor.h>

  /*
   * Include the apic definitions for x86 to have the APIC timer related defines
   * available also for UP (on SMP it gets magically included via linux/smp.h).
   * asm/acpi.h is not an option, as it would require more include magic. Also
   * creating an empty asm-ia64/apic.h would just trade pest vs. cholera.
   */
  #ifdef CONFIG_X86
  #include <asm/apic.h>
  #endif

  #define ACPI_PROCESSOR_CLASS            "processor"

  #define _COMPONENT              ACPI_PROCESSOR_COMPONENT

  ACPI_MODULE_NAME("processor_idle");

  #define ACPI_IDLE_STATE_START	(IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX) ? 1 : 0)

  static unsigned int max_cstate __read_mostly = ACPI_PROCESSOR_MAX_POWER;
  module_param(max_cstate, uint, 0000);

  static unsigned int nocst __read_mostly;

  module_param(nocst, uint, 0000);

  static int bm_check_disable __read_mostly;
  module_param(bm_check_disable, uint, 0000);

  static unsigned int latency_factor __read_mostly = 2;

  module_param(latency_factor, uint, 0644);

  static DEFINE_PER_CPU(struct cpuidle_device *, acpi_cpuidle_device);

  struct cpuidle_driver acpi_idle_driver = {
  	.name =		"acpi_idle",
  	.owner =	THIS_MODULE,
  };
  
  #ifdef CONFIG_ACPI_PROCESSOR_CSTATE

  static
  DEFINE_PER_CPU(struct acpi_processor_cx * [CPUIDLE_STATE_MAX], acpi_cstate);

  static int disabled_by_idle_boot_param(void)
  {
  	return boot_option_idle_override == IDLE_POLL ||

  		boot_option_idle_override == IDLE_HALT;
  }

  /*
   * IBM ThinkPad R40e crashes mysteriously when going into C2 or C3.
   * For now disable this. Probably a bug somewhere else.
   *
   * To skip this limit, boot/load with a large max_cstate limit.
   */

  static int set_max_cstate(const struct dmi_system_id *id)

  {
  	if (max_cstate > ACPI_PROCESSOR_MAX_POWER)
  		return 0;

  	pr_notice("%s detected - limiting to C%ld max_cstate."
  		  " Override with \"processor.max_cstate=%d\"
  ", id->ident,
  		  (long)id->driver_data, ACPI_PROCESSOR_MAX_POWER + 1);

  	max_cstate = (long)id->driver_data;

  
  	return 0;
  }

  static const struct dmi_system_id processor_power_dmi_table[] = {

  	{ set_max_cstate, "Clevo 5600D", {
  	  DMI_MATCH(DMI_BIOS_VENDOR,"Phoenix Technologies LTD"),
  	  DMI_MATCH(DMI_BIOS_VERSION,"SHE845M0.86C.0013.D.0302131307")},

  	 (void *)2},

  	{ set_max_cstate, "Pavilion zv5000", {
  	  DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
  	  DMI_MATCH(DMI_PRODUCT_NAME,"Pavilion zv5000 (DS502A#ABA)")},
  	 (void *)1},
  	{ set_max_cstate, "Asus L8400B", {
  	  DMI_MATCH(DMI_SYS_VENDOR, "ASUSTeK Computer Inc."),
  	  DMI_MATCH(DMI_PRODUCT_NAME,"L8400B series Notebook PC")},
  	 (void *)1},

  	{},
  };

  /*
   * Callers should disable interrupts before the call and enable
   * interrupts after return.
   */

  static void __cpuidle acpi_safe_halt(void)

  {

  	if (!tif_need_resched()) {

  		safe_halt();

  		local_irq_disable();
  	}

  }

  #ifdef ARCH_APICTIMER_STOPS_ON_C3
  
  /*
   * Some BIOS implementations switch to C3 in the published C2 state.

   * This seems to be a common problem on AMD boxen, but other vendors
   * are affected too. We pick the most conservative approach: we assume
   * that the local APIC stops in both C2 and C3.

   */

  static void lapic_timer_check_state(int state, struct acpi_processor *pr,

  				   struct acpi_processor_cx *cx)
  {
  	struct acpi_processor_power *pwr = &pr->power;

  	u8 type = local_apic_timer_c2_ok ? ACPI_STATE_C3 : ACPI_STATE_C2;

  	if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
  		return;

  	if (boot_cpu_has_bug(X86_BUG_AMD_APIC_C1E))

  		type = ACPI_STATE_C1;

  	/*
  	 * Check, if one of the previous states already marked the lapic
  	 * unstable
  	 */
  	if (pwr->timer_broadcast_on_state < state)
  		return;

  	if (cx->type >= type)

  		pr->power.timer_broadcast_on_state = state;

  }

  static void __lapic_timer_propagate_broadcast(void *arg)

  {

  	struct acpi_processor *pr = (struct acpi_processor *) arg;

  	if (pr->power.timer_broadcast_on_state < INT_MAX)
  		tick_broadcast_enable();
  	else
  		tick_broadcast_disable();

  }

  static void lapic_timer_propagate_broadcast(struct acpi_processor *pr)
  {
  	smp_call_function_single(pr->id, __lapic_timer_propagate_broadcast,
  				 (void *)pr, 1);
  }

  /* Power(C) State timer broadcast control */

  static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
  					struct acpi_processor_cx *cx)

  {

  	return cx - pr->power.states >= pr->power.timer_broadcast_on_state;

  }
  
  #else

  static void lapic_timer_check_state(int state, struct acpi_processor *pr,

  				   struct acpi_processor_cx *cstate) { }

  static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { }

  
  static bool lapic_timer_needs_broadcast(struct acpi_processor *pr,
  					struct acpi_processor_cx *cx)

  {

  	return false;

  }

  
  #endif

  #if defined(CONFIG_X86)

  static void tsc_check_state(int state)

  {
  	switch (boot_cpu_data.x86_vendor) {

  	case X86_VENDOR_HYGON:

  	case X86_VENDOR_AMD:

  	case X86_VENDOR_INTEL:

  	case X86_VENDOR_CENTAUR:

  	case X86_VENDOR_ZHAOXIN:

  		/*
  		 * AMD Fam10h TSC will tick in all
  		 * C/P/S0/S1 states when this bit is set.
  		 */

  		if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))

  			return;

  		fallthrough;

  	default:

  		/* TSC could halt in idle, so notify users */
  		if (state > ACPI_STATE_C1)
  			mark_tsc_unstable("TSC halts in idle");

  	}
  }

  #else
  static void tsc_check_state(int state) { return; }

  #endif

  static int acpi_processor_get_power_info_fadt(struct acpi_processor *pr)

  {

  	if (!pr->pblk)

  		return -ENODEV;

  	/* if info is obtained from pblk/fadt, type equals state */

  	pr->power.states[ACPI_STATE_C2].type = ACPI_STATE_C2;
  	pr->power.states[ACPI_STATE_C3].type = ACPI_STATE_C3;

  #ifndef CONFIG_HOTPLUG_CPU
  	/*
  	 * Check for P_LVL2_UP flag before entering C2 and above on

  	 * an SMP system.

  	 */

  	if ((num_online_cpus() > 1) &&

  	    !(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED))

  		return -ENODEV;

  #endif

  	/* determine C2 and C3 address from pblk */
  	pr->power.states[ACPI_STATE_C2].address = pr->pblk + 4;
  	pr->power.states[ACPI_STATE_C3].address = pr->pblk + 5;
  
  	/* determine latencies from FADT */

  	pr->power.states[ACPI_STATE_C2].latency = acpi_gbl_FADT.c2_latency;
  	pr->power.states[ACPI_STATE_C3].latency = acpi_gbl_FADT.c3_latency;

  	/*
  	 * FADT specified C2 latency must be less than or equal to
  	 * 100 microseconds.
  	 */

  	if (acpi_gbl_FADT.c2_latency > ACPI_PROCESSOR_MAX_C2_LATENCY) {

  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  			"C2 latency too large [%d]
  ", acpi_gbl_FADT.c2_latency));

  		/* invalidate C2 */
  		pr->power.states[ACPI_STATE_C2].address = 0;
  	}

  	/*
  	 * FADT supplied C3 latency must be less than or equal to
  	 * 1000 microseconds.
  	 */

  	if (acpi_gbl_FADT.c3_latency > ACPI_PROCESSOR_MAX_C3_LATENCY) {

  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  			"C3 latency too large [%d]
  ", acpi_gbl_FADT.c3_latency));

  		/* invalidate C3 */
  		pr->power.states[ACPI_STATE_C3].address = 0;
  	}

  	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  			  "lvl2[0x%08x] lvl3[0x%08x]
  ",
  			  pr->power.states[ACPI_STATE_C2].address,
  			  pr->power.states[ACPI_STATE_C3].address));

  	snprintf(pr->power.states[ACPI_STATE_C2].desc,
  			 ACPI_CX_DESC_LEN, "ACPI P_LVL2 IOPORT 0x%x",
  			 pr->power.states[ACPI_STATE_C2].address);
  	snprintf(pr->power.states[ACPI_STATE_C3].desc,
  			 ACPI_CX_DESC_LEN, "ACPI P_LVL3 IOPORT 0x%x",
  			 pr->power.states[ACPI_STATE_C3].address);

  	return 0;

  }

  static int acpi_processor_get_power_info_default(struct acpi_processor *pr)

  {

  	if (!pr->power.states[ACPI_STATE_C1].valid) {
  		/* set the first C-State to C1 */
  		/* all processors need to support C1 */
  		pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1;
  		pr->power.states[ACPI_STATE_C1].valid = 1;

  		pr->power.states[ACPI_STATE_C1].entry_method = ACPI_CSTATE_HALT;

  
  		snprintf(pr->power.states[ACPI_STATE_C1].desc,
  			 ACPI_CX_DESC_LEN, "ACPI HLT");

  	}
  	/* the C0 state only exists as a filler in our array */

  	pr->power.states[ACPI_STATE_C0].valid = 1;

  	return 0;

  }

  static int acpi_processor_get_power_info_cst(struct acpi_processor *pr)
  {
  	int ret;
  
  	if (nocst)
  		return -ENODEV;
  
  	ret = acpi_processor_evaluate_cst(pr->handle, pr->id, &pr->power);
  	if (ret)
  		return ret;

  	if (!pr->power.count)

  		return -EFAULT;
  
  	pr->flags.has_cst = 1;
  	return 0;
  }

  static void acpi_processor_power_verify_c3(struct acpi_processor *pr,
  					   struct acpi_processor_cx *cx)

  {

  	static int bm_check_flag = -1;
  	static int bm_control_flag = -1;

  
  	if (!cx->address)

  		return;

  
  	/*

  	 * PIIX4 Erratum #18: We don't support C3 when Type-F (fast)
  	 * DMA transfers are used by any ISA device to avoid livelock.
  	 * Note that we could disable Type-F DMA (as recommended by
  	 * the erratum), but this is known to disrupt certain ISA
  	 * devices thus we take the conservative approach.
  	 */
  	else if (errata.piix4.fdma) {
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  				  "C3 not supported on PIIX4 with Type-F DMA
  "));

  		return;

  	}

  	/* All the logic here assumes flags.bm_check is same across all CPUs */

  	if (bm_check_flag == -1) {

  		/* Determine whether bm_check is needed based on CPU  */
  		acpi_processor_power_init_bm_check(&(pr->flags), pr->id);
  		bm_check_flag = pr->flags.bm_check;

  		bm_control_flag = pr->flags.bm_control;

  	} else {
  		pr->flags.bm_check = bm_check_flag;

  		pr->flags.bm_control = bm_control_flag;

  	}
  
  	if (pr->flags.bm_check) {

  		if (!pr->flags.bm_control) {

  			if (pr->flags.has_cst != 1) {
  				/* bus mastering control is necessary */
  				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  					"C3 support requires BM control
  "));
  				return;
  			} else {
  				/* Here we enter C3 without bus mastering */
  				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  					"C3 support without BM control
  "));
  			}

  		}
  	} else {

  		/*
  		 * WBINVD should be set in fadt, for C3 state to be
  		 * supported on when bm_check is not required.
  		 */

  		if (!(acpi_gbl_FADT.flags & ACPI_FADT_WBINVD)) {

  			ACPI_DEBUG_PRINT((ACPI_DB_INFO,

  					  "Cache invalidation should work properly"
  					  " for C3 to be enabled on SMP systems
  "));

  			return;

  		}

  	}

  	/*
  	 * Otherwise we've met all of our C3 requirements.
  	 * Normalize the C3 latency to expidite policy.  Enable
  	 * checking of bus mastering status (bm_check) so we can
  	 * use this in our C3 policy
  	 */
  	cx->valid = 1;

  	/*
  	 * On older chipsets, BM_RLD needs to be set
  	 * in order for Bus Master activity to wake the
  	 * system from C3.  Newer chipsets handle DMA
  	 * during C3 automatically and BM_RLD is a NOP.
  	 * In either case, the proper way to
  	 * handle BM_RLD is to set it and leave it set.
  	 */

  	acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_RLD, 1);

  	return;

  }

  static int acpi_processor_power_verify(struct acpi_processor *pr)
  {
  	unsigned int i;
  	unsigned int working = 0;

  	pr->power.timer_broadcast_on_state = INT_MAX;

  	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {

  		struct acpi_processor_cx *cx = &pr->power.states[i];
  
  		switch (cx->type) {
  		case ACPI_STATE_C1:
  			cx->valid = 1;
  			break;
  
  		case ACPI_STATE_C2:

  			if (!cx->address)
  				break;

  			cx->valid = 1;

  			break;
  
  		case ACPI_STATE_C3:
  			acpi_processor_power_verify_c3(pr, cx);
  			break;
  		}

  		if (!cx->valid)
  			continue;

  		lapic_timer_check_state(i, pr, cx);
  		tsc_check_state(cx->type);
  		working++;

  	}

  	lapic_timer_propagate_broadcast(pr);

  
  	return (working);
  }

  static int acpi_processor_get_cstate_info(struct acpi_processor *pr)

  {
  	unsigned int i;
  	int result;

  
  	/* NOTE: the idle thread may not be running while calling
  	 * this function */

  	/* Zero initialize all the C-states info. */
  	memset(pr->power.states, 0, sizeof(pr->power.states));

  	result = acpi_processor_get_power_info_cst(pr);

  	if (result == -ENODEV)

  		result = acpi_processor_get_power_info_fadt(pr);

  	if (result)
  		return result;
  
  	acpi_processor_get_power_info_default(pr);

  	pr->power.count = acpi_processor_power_verify(pr);

  	/*
  	 * if one state of type C2 or C3 is available, mark this
  	 * CPU as being "idle manageable"
  	 */
  	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER; i++) {

  		if (pr->power.states[i].valid) {

  			pr->power.count = i;

  			pr->flags.power = 1;

  		}

  	}

  	return 0;

  }

  /**
   * acpi_idle_bm_check - checks if bus master activity was detected
   */
  static int acpi_idle_bm_check(void)
  {
  	u32 bm_status = 0;

  	if (bm_check_disable)
  		return 0;

  	acpi_read_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);

  	if (bm_status)

  		acpi_write_bit_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);

  	/*
  	 * PIIX4 Erratum #18: Note that BM_STS doesn't always reflect
  	 * the true state of bus mastering activity; forcing us to
  	 * manually check the BMIDEA bit of each IDE channel.
  	 */
  	else if (errata.piix4.bmisx) {
  		if ((inb_p(errata.piix4.bmisx + 0x02) & 0x01)
  		    || (inb_p(errata.piix4.bmisx + 0x0A) & 0x01))
  			bm_status = 1;
  	}
  	return bm_status;
  }

  static void wait_for_freeze(void)
  {
  #ifdef	CONFIG_X86
  	/* No delay is needed if we are in guest */
  	if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
  		return;
  #endif
  	/* Dummy wait op - must do something useless after P_LVL2 read
  	   because chipsets cannot guarantee that STPCLK# signal
  	   gets asserted in time to freeze execution properly. */
  	inl(acpi_gbl_FADT.xpm_timer_block.address);
  }

  /**

   * acpi_idle_do_entry - enter idle state using the appropriate method

   * @cx: cstate data

   *
   * Caller disables interrupt before call and enables interrupt after return.

   */

  static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)

  {

  	if (cx->entry_method == ACPI_CSTATE_FFH) {

  		/* Call into architectural FFH based C-state */
  		acpi_processor_ffh_cstate_enter(cx);

  	} else if (cx->entry_method == ACPI_CSTATE_HALT) {
  		acpi_safe_halt();

  	} else {

  		/* IO port based C-state */
  		inb(cx->address);

  		wait_for_freeze();

  	}
  }
  
  /**

   * acpi_idle_play_dead - enters an ACPI state for long-term idle (i.e. off-lining)
   * @dev: the target CPU
   * @index: the index of suggested state
   */
  static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
  {

  	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);

  
  	ACPI_FLUSH_CPU_CACHE();
  
  	while (1) {
  
  		if (cx->entry_method == ACPI_CSTATE_HALT)

  			safe_halt();

  		else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
  			inb(cx->address);

  			wait_for_freeze();

  		} else
  			return -ENODEV;
  	}
  
  	/* Never reached */
  	return 0;
  }

  static bool acpi_idle_fallback_to_c1(struct acpi_processor *pr)
  {

  	return IS_ENABLED(CONFIG_HOTPLUG_CPU) && !pr->flags.has_cst &&
  		!(acpi_gbl_FADT.flags & ACPI_FADT_C2_MP_SUPPORTED);

  }

  static int c3_cpu_count;

  static DEFINE_RAW_SPINLOCK(c3_lock);

  
  /**
   * acpi_idle_enter_bm - enters C3 with proper BM handling

   * @drv: cpuidle driver

   * @pr: Target processor
   * @cx: Target state context

   * @index: index of target state

   */

  static int acpi_idle_enter_bm(struct cpuidle_driver *drv,
  			       struct acpi_processor *pr,
  			       struct acpi_processor_cx *cx,
  			       int index)

  {

  	static struct acpi_processor_cx safe_cx = {
  		.entry_method = ACPI_CSTATE_HALT,
  	};

  	/*

  	 * disable bus master
  	 * bm_check implies we need ARB_DIS

  	 * bm_control implies whether we can do ARB_DIS
  	 *

  	 * That leaves a case where bm_check is set and bm_control is not set.
  	 * In that case we cannot do much, we enter C3 without doing anything.

  	 */

  	bool dis_bm = pr->flags.bm_control;
  
  	/* If we can skip BM, demote to a safe state. */
  	if (!cx->bm_sts_skip && acpi_idle_bm_check()) {
  		dis_bm = false;
  		index = drv->safe_state_index;
  		if (index >= 0) {
  			cx = this_cpu_read(acpi_cstate[index]);
  		} else {
  			cx = &safe_cx;
  			index = -EBUSY;
  		}
  	}
  
  	if (dis_bm) {

  		raw_spin_lock(&c3_lock);

  		c3_cpu_count++;
  		/* Disable bus master arbitration when all CPUs are in C3 */
  		if (c3_cpu_count == num_online_cpus())

  			acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);

  		raw_spin_unlock(&c3_lock);

  	}

  	rcu_idle_enter();

  	acpi_idle_do_entry(cx);

  	rcu_idle_exit();

  	/* Re-enable bus master arbitration */

  	if (dis_bm) {

  		raw_spin_lock(&c3_lock);

  		acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);

  		c3_cpu_count--;

  		raw_spin_unlock(&c3_lock);

  	}

  
  	return index;

  }
  
  static int acpi_idle_enter(struct cpuidle_device *dev,
  			   struct cpuidle_driver *drv, int index)
  {
  	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
  	struct acpi_processor *pr;
  
  	pr = __this_cpu_read(processors);
  	if (unlikely(!pr))
  		return -EINVAL;
  
  	if (cx->type != ACPI_STATE_C1) {

  		if (cx->type == ACPI_STATE_C3 && pr->flags.bm_check)
  			return acpi_idle_enter_bm(drv, pr, cx, index);
  
  		/* C2 to C1 demotion. */

  		if (acpi_idle_fallback_to_c1(pr) && num_online_cpus() > 1) {

  			index = ACPI_IDLE_STATE_START;

  			cx = per_cpu(acpi_cstate[index], dev->cpu);

  		}
  	}

  	if (cx->type == ACPI_STATE_C3)
  		ACPI_FLUSH_CPU_CACHE();
  
  	acpi_idle_do_entry(cx);

  	return index;

  }

  static int acpi_idle_enter_s2idle(struct cpuidle_device *dev,
  				  struct cpuidle_driver *drv, int index)

  {
  	struct acpi_processor_cx *cx = per_cpu(acpi_cstate[index], dev->cpu);
  
  	if (cx->type == ACPI_STATE_C3) {
  		struct acpi_processor *pr = __this_cpu_read(processors);
  
  		if (unlikely(!pr))

  			return 0;

  
  		if (pr->flags.bm_check) {

  			u8 bm_sts_skip = cx->bm_sts_skip;
  
  			/* Don't check BM_STS, do an unconditional ARB_DIS for S2IDLE */
  			cx->bm_sts_skip = 1;
  			acpi_idle_enter_bm(drv, pr, cx, index);
  			cx->bm_sts_skip = bm_sts_skip;

  			return 0;

  		} else {
  			ACPI_FLUSH_CPU_CACHE();
  		}
  	}
  	acpi_idle_do_entry(cx);

  
  	return 0;

  }

  static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
  					   struct cpuidle_device *dev)

  {

  	int i, count = ACPI_IDLE_STATE_START;

  	struct acpi_processor_cx *cx;

  	struct cpuidle_state *state;

  	if (max_cstate == 0)
  		max_cstate = 1;

  	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {

  		state = &acpi_idle_driver.states[count];

  		cx = &pr->power.states[i];

  
  		if (!cx->valid)
  			continue;

  		per_cpu(acpi_cstate[count], dev->cpu) = cx;

  		if (lapic_timer_needs_broadcast(pr, cx))

  			state->flags |= CPUIDLE_FLAG_TIMER_STOP;

  		if (cx->type == ACPI_STATE_C3) {

  			state->flags |= CPUIDLE_FLAG_TLB_FLUSHED;

  			if (pr->flags.bm_check)
  				state->flags |= CPUIDLE_FLAG_RCU_IDLE;
  		}

  		count++;
  		if (count == CPUIDLE_STATE_MAX)
  			break;
  	}

  	if (!count)
  		return -EINVAL;
  
  	return 0;
  }

  static int acpi_processor_setup_cstates(struct acpi_processor *pr)

  {

  	int i, count;

  	struct acpi_processor_cx *cx;
  	struct cpuidle_state *state;
  	struct cpuidle_driver *drv = &acpi_idle_driver;

  	if (max_cstate == 0)
  		max_cstate = 1;

  	if (IS_ENABLED(CONFIG_ARCH_HAS_CPU_RELAX)) {
  		cpuidle_poll_state_init(drv);
  		count = 1;
  	} else {
  		count = 0;
  	}

  	for (i = 1; i < ACPI_PROCESSOR_MAX_POWER && i <= max_cstate; i++) {
  		cx = &pr->power.states[i];

  
  		if (!cx->valid)
  			continue;

  		state = &drv->states[count];

  		snprintf(state->name, CPUIDLE_NAME_LEN, "C%d", i);

  		strlcpy(state->desc, cx->desc, CPUIDLE_DESC_LEN);

  		state->exit_latency = cx->latency;

  		state->target_residency = cx->latency * latency_factor;

  		state->enter = acpi_idle_enter;

  
  		state->flags = 0;

  		if (cx->type == ACPI_STATE_C1 || cx->type == ACPI_STATE_C2) {

  			state->enter_dead = acpi_idle_play_dead;

  			drv->safe_state_index = count;

  		}

  		/*

  		 * Halt-induced C1 is not good for ->enter_s2idle, because it

  		 * re-enables interrupts on exit.  Moreover, C1 is generally not
  		 * particularly interesting from the suspend-to-idle angle, so
  		 * avoid C1 and the situations in which we may need to fall back
  		 * to it altogether.
  		 */
  		if (cx->type != ACPI_STATE_C1 && !acpi_idle_fallback_to_c1(pr))

  			state->enter_s2idle = acpi_idle_enter_s2idle;

  
  		count++;

  		if (count == CPUIDLE_STATE_MAX)
  			break;

  	}

  	drv->state_count = count;

  
  	if (!count)
  		return -EINVAL;

  	return 0;
  }

  static inline void acpi_processor_cstate_first_run_checks(void)
  {

  	static int first_run;
  
  	if (first_run)
  		return;
  	dmi_check_system(processor_power_dmi_table);
  	max_cstate = acpi_processor_cstate_check(max_cstate);
  	if (max_cstate < ACPI_C_STATES_MAX)
  		pr_notice("ACPI: processor limited to max C-state %d
  ",
  			  max_cstate);
  	first_run++;

  	if (nocst)
  		return;
  
  	acpi_processor_claim_cst_control();

  }
  #else
  
  static inline int disabled_by_idle_boot_param(void) { return 0; }
  static inline void acpi_processor_cstate_first_run_checks(void) { }

  static int acpi_processor_get_cstate_info(struct acpi_processor *pr)

  {
  	return -ENODEV;
  }
  
  static int acpi_processor_setup_cpuidle_cx(struct acpi_processor *pr,
  					   struct cpuidle_device *dev)
  {
  	return -EINVAL;
  }

  static int acpi_processor_setup_cstates(struct acpi_processor *pr)

  {
  	return -EINVAL;
  }
  
  #endif /* CONFIG_ACPI_PROCESSOR_CSTATE */

  struct acpi_lpi_states_array {
  	unsigned int size;
  	unsigned int composite_states_size;
  	struct acpi_lpi_state *entries;
  	struct acpi_lpi_state *composite_states[ACPI_PROCESSOR_MAX_POWER];
  };
  
  static int obj_get_integer(union acpi_object *obj, u32 *value)
  {
  	if (obj->type != ACPI_TYPE_INTEGER)
  		return -EINVAL;
  
  	*value = obj->integer.value;
  	return 0;
  }
  
  static int acpi_processor_evaluate_lpi(acpi_handle handle,
  				       struct acpi_lpi_states_array *info)
  {
  	acpi_status status;
  	int ret = 0;
  	int pkg_count, state_idx = 1, loop;
  	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  	union acpi_object *lpi_data;
  	struct acpi_lpi_state *lpi_state;
  
  	status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer);
  	if (ACPI_FAILURE(status)) {
  		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No _LPI, giving up
  "));
  		return -ENODEV;
  	}
  
  	lpi_data = buffer.pointer;
  
  	/* There must be at least 4 elements = 3 elements + 1 package */
  	if (!lpi_data || lpi_data->type != ACPI_TYPE_PACKAGE ||
  	    lpi_data->package.count < 4) {
  		pr_debug("not enough elements in _LPI
  ");
  		ret = -ENODATA;
  		goto end;
  	}
  
  	pkg_count = lpi_data->package.elements[2].integer.value;
  
  	/* Validate number of power states. */
  	if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) {
  		pr_debug("count given by _LPI is not valid
  ");
  		ret = -ENODATA;
  		goto end;
  	}
  
  	lpi_state = kcalloc(pkg_count, sizeof(*lpi_state), GFP_KERNEL);
  	if (!lpi_state) {
  		ret = -ENOMEM;
  		goto end;
  	}
  
  	info->size = pkg_count;
  	info->entries = lpi_state;
  
  	/* LPI States start at index 3 */
  	for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) {
  		union acpi_object *element, *pkg_elem, *obj;
  
  		element = &lpi_data->package.elements[loop];
  		if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7)
  			continue;
  
  		pkg_elem = element->package.elements;
  
  		obj = pkg_elem + 6;
  		if (obj->type == ACPI_TYPE_BUFFER) {
  			struct acpi_power_register *reg;
  
  			reg = (struct acpi_power_register *)obj->buffer.pointer;
  			if (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO &&
  			    reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)
  				continue;
  
  			lpi_state->address = reg->address;
  			lpi_state->entry_method =
  				reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE ?
  				ACPI_CSTATE_FFH : ACPI_CSTATE_SYSTEMIO;
  		} else if (obj->type == ACPI_TYPE_INTEGER) {
  			lpi_state->entry_method = ACPI_CSTATE_INTEGER;
  			lpi_state->address = obj->integer.value;
  		} else {
  			continue;
  		}
  
  		/* elements[7,8] skipped for now i.e. Residency/Usage counter*/
  
  		obj = pkg_elem + 9;
  		if (obj->type == ACPI_TYPE_STRING)
  			strlcpy(lpi_state->desc, obj->string.pointer,
  				ACPI_CX_DESC_LEN);
  
  		lpi_state->index = state_idx;
  		if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) {
  			pr_debug("No min. residency found, assuming 10 us
  ");
  			lpi_state->min_residency = 10;
  		}
  
  		if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) {
  			pr_debug("No wakeup residency found, assuming 10 us
  ");
  			lpi_state->wake_latency = 10;
  		}
  
  		if (obj_get_integer(pkg_elem + 2, &lpi_state->flags))
  			lpi_state->flags = 0;
  
  		if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags))
  			lpi_state->arch_flags = 0;
  
  		if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq))
  			lpi_state->res_cnt_freq = 1;
  
  		if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state))
  			lpi_state->enable_parent_state = 0;
  	}
  
  	acpi_handle_debug(handle, "Found %d power states
  ", state_idx);
  end:
  	kfree(buffer.pointer);
  	return ret;
  }
  
  /*
   * flat_state_cnt - the number of composite LPI states after the process of flattening
   */
  static int flat_state_cnt;
  
  /**
   * combine_lpi_states - combine local and parent LPI states to form a composite LPI state
   *
   * @local: local LPI state
   * @parent: parent LPI state
   * @result: composite LPI state
   */
  static bool combine_lpi_states(struct acpi_lpi_state *local,
  			       struct acpi_lpi_state *parent,
  			       struct acpi_lpi_state *result)
  {
  	if (parent->entry_method == ACPI_CSTATE_INTEGER) {
  		if (!parent->address) /* 0 means autopromotable */
  			return false;
  		result->address = local->address + parent->address;
  	} else {
  		result->address = parent->address;
  	}
  
  	result->min_residency = max(local->min_residency, parent->min_residency);
  	result->wake_latency = local->wake_latency + parent->wake_latency;
  	result->enable_parent_state = parent->enable_parent_state;
  	result->entry_method = local->entry_method;
  
  	result->flags = parent->flags;
  	result->arch_flags = parent->arch_flags;
  	result->index = parent->index;
  
  	strlcpy(result->desc, local->desc, ACPI_CX_DESC_LEN);
  	strlcat(result->desc, "+", ACPI_CX_DESC_LEN);
  	strlcat(result->desc, parent->desc, ACPI_CX_DESC_LEN);
  	return true;
  }
  
  #define ACPI_LPI_STATE_FLAGS_ENABLED			BIT(0)
  
  static void stash_composite_state(struct acpi_lpi_states_array *curr_level,
  				  struct acpi_lpi_state *t)
  {
  	curr_level->composite_states[curr_level->composite_states_size++] = t;
  }
  
  static int flatten_lpi_states(struct acpi_processor *pr,
  			      struct acpi_lpi_states_array *curr_level,
  			      struct acpi_lpi_states_array *prev_level)
  {
  	int i, j, state_count = curr_level->size;
  	struct acpi_lpi_state *p, *t = curr_level->entries;
  
  	curr_level->composite_states_size = 0;
  	for (j = 0; j < state_count; j++, t++) {
  		struct acpi_lpi_state *flpi;
  
  		if (!(t->flags & ACPI_LPI_STATE_FLAGS_ENABLED))
  			continue;
  
  		if (flat_state_cnt >= ACPI_PROCESSOR_MAX_POWER) {
  			pr_warn("Limiting number of LPI states to max (%d)
  ",
  				ACPI_PROCESSOR_MAX_POWER);
  			pr_warn("Please increase ACPI_PROCESSOR_MAX_POWER if needed.
  ");
  			break;
  		}
  
  		flpi = &pr->power.lpi_states[flat_state_cnt];
  
  		if (!prev_level) { /* leaf/processor node */
  			memcpy(flpi, t, sizeof(*t));
  			stash_composite_state(curr_level, flpi);
  			flat_state_cnt++;
  			continue;
  		}
  
  		for (i = 0; i < prev_level->composite_states_size; i++) {
  			p = prev_level->composite_states[i];
  			if (t->index <= p->enable_parent_state &&
  			    combine_lpi_states(p, t, flpi)) {
  				stash_composite_state(curr_level, flpi);
  				flat_state_cnt++;
  				flpi++;
  			}
  		}
  	}
  
  	kfree(curr_level->entries);
  	return 0;
  }
  
  static int acpi_processor_get_lpi_info(struct acpi_processor *pr)
  {
  	int ret, i;
  	acpi_status status;
  	acpi_handle handle = pr->handle, pr_ahandle;
  	struct acpi_device *d = NULL;
  	struct acpi_lpi_states_array info[2], *tmp, *prev, *curr;
  
  	if (!osc_pc_lpi_support_confirmed)
  		return -EOPNOTSUPP;
  
  	if (!acpi_has_method(handle, "_LPI"))
  		return -EINVAL;
  
  	flat_state_cnt = 0;
  	prev = &info[0];
  	curr = &info[1];
  	handle = pr->handle;
  	ret = acpi_processor_evaluate_lpi(handle, prev);
  	if (ret)
  		return ret;
  	flatten_lpi_states(pr, prev, NULL);
  
  	status = acpi_get_parent(handle, &pr_ahandle);
  	while (ACPI_SUCCESS(status)) {
  		acpi_bus_get_device(pr_ahandle, &d);
  		handle = pr_ahandle;
  
  		if (strcmp(acpi_device_hid(d), ACPI_PROCESSOR_CONTAINER_HID))
  			break;
  
  		/* can be optional ? */
  		if (!acpi_has_method(handle, "_LPI"))
  			break;
  
  		ret = acpi_processor_evaluate_lpi(handle, curr);
  		if (ret)
  			break;
  
  		/* flatten all the LPI states in this level of hierarchy */
  		flatten_lpi_states(pr, curr, prev);
  
  		tmp = prev, prev = curr, curr = tmp;
  
  		status = acpi_get_parent(handle, &pr_ahandle);
  	}
  
  	pr->power.count = flat_state_cnt;
  	/* reset the index after flattening */
  	for (i = 0; i < pr->power.count; i++)
  		pr->power.lpi_states[i].index = i;
  
  	/* Tell driver that _LPI is supported. */
  	pr->flags.has_lpi = 1;
  	pr->flags.power = 1;
  
  	return 0;
  }
  
  int __weak acpi_processor_ffh_lpi_probe(unsigned int cpu)
  {
  	return -ENODEV;
  }
  
  int __weak acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
  {
  	return -ENODEV;
  }
  
  /**
   * acpi_idle_lpi_enter - enters an ACPI any LPI state
   * @dev: the target CPU
   * @drv: cpuidle driver containing cpuidle state info
   * @index: index of target state
   *
   * Return: 0 for success or negative value for error
   */
  static int acpi_idle_lpi_enter(struct cpuidle_device *dev,
  			       struct cpuidle_driver *drv, int index)
  {
  	struct acpi_processor *pr;
  	struct acpi_lpi_state *lpi;
  
  	pr = __this_cpu_read(processors);
  
  	if (unlikely(!pr))
  		return -EINVAL;
  
  	lpi = &pr->power.lpi_states[index];
  	if (lpi->entry_method == ACPI_CSTATE_FFH)
  		return acpi_processor_ffh_lpi_enter(lpi);
  
  	return -EINVAL;
  }
  
  static int acpi_processor_setup_lpi_states(struct acpi_processor *pr)
  {
  	int i;
  	struct acpi_lpi_state *lpi;
  	struct cpuidle_state *state;
  	struct cpuidle_driver *drv = &acpi_idle_driver;
  
  	if (!pr->flags.has_lpi)
  		return -EOPNOTSUPP;
  
  	for (i = 0; i < pr->power.count && i < CPUIDLE_STATE_MAX; i++) {
  		lpi = &pr->power.lpi_states[i];
  
  		state = &drv->states[i];
  		snprintf(state->name, CPUIDLE_NAME_LEN, "LPI-%d", i);
  		strlcpy(state->desc, lpi->desc, CPUIDLE_DESC_LEN);
  		state->exit_latency = lpi->wake_latency;
  		state->target_residency = lpi->min_residency;
  		if (lpi->arch_flags)
  			state->flags |= CPUIDLE_FLAG_TIMER_STOP;
  		state->enter = acpi_idle_lpi_enter;
  		drv->safe_state_index = i;
  	}
  
  	drv->state_count = i;
  
  	return 0;
  }
  
  /**
   * acpi_processor_setup_cpuidle_states- prepares and configures cpuidle
   * global state data i.e. idle routines
   *
   * @pr: the ACPI processor
   */
  static int acpi_processor_setup_cpuidle_states(struct acpi_processor *pr)
  {
  	int i;
  	struct cpuidle_driver *drv = &acpi_idle_driver;
  
  	if (!pr->flags.power_setup_done || !pr->flags.power)
  		return -EINVAL;
  
  	drv->safe_state_index = -1;

  	for (i = ACPI_IDLE_STATE_START; i < CPUIDLE_STATE_MAX; i++) {

  		drv->states[i].name[0] = '\0';
  		drv->states[i].desc[0] = '\0';
  	}
  
  	if (pr->flags.has_lpi)
  		return acpi_processor_setup_lpi_states(pr);
  
  	return acpi_processor_setup_cstates(pr);
  }
  
  /**
   * acpi_processor_setup_cpuidle_dev - prepares and configures CPUIDLE
   * device i.e. per-cpu data
   *
   * @pr: the ACPI processor
   * @dev : the cpuidle device
   */
  static int acpi_processor_setup_cpuidle_dev(struct acpi_processor *pr,
  					    struct cpuidle_device *dev)
  {
  	if (!pr->flags.power_setup_done || !pr->flags.power || !dev)
  		return -EINVAL;
  
  	dev->cpu = pr->id;
  	if (pr->flags.has_lpi)
  		return acpi_processor_ffh_lpi_probe(pr->id);
  
  	return acpi_processor_setup_cpuidle_cx(pr, dev);
  }
  
  static int acpi_processor_get_power_info(struct acpi_processor *pr)
  {
  	int ret;
  
  	ret = acpi_processor_get_lpi_info(pr);
  	if (ret)
  		ret = acpi_processor_get_cstate_info(pr);
  
  	return ret;
  }

  int acpi_processor_hotplug(struct acpi_processor *pr)

  {

  	int ret = 0;

  	struct cpuidle_device *dev;

  	if (disabled_by_idle_boot_param())

  		return 0;

  	if (!pr->flags.power_setup_done)
  		return -ENODEV;

  	dev = per_cpu(acpi_cpuidle_device, pr->id);

  	cpuidle_pause_and_lock();

  	cpuidle_disable_device(dev);

  	ret = acpi_processor_get_power_info(pr);
  	if (!ret && pr->flags.power) {
  		acpi_processor_setup_cpuidle_dev(pr, dev);

  		ret = cpuidle_enable_device(dev);

  	}

  	cpuidle_resume_and_unlock();
  
  	return ret;
  }

  int acpi_processor_power_state_has_changed(struct acpi_processor *pr)

  {
  	int cpu;
  	struct acpi_processor *_pr;

  	struct cpuidle_device *dev;

  
  	if (disabled_by_idle_boot_param())
  		return 0;

  	if (!pr->flags.power_setup_done)
  		return -ENODEV;
  
  	/*
  	 * FIXME:  Design the ACPI notification to make it once per
  	 * system instead of once per-cpu.  This condition is a hack
  	 * to make the code that updates C-States be called once.
  	 */

  	if (pr->id == 0 && cpuidle_get_driver() == &acpi_idle_driver) {

  		/* Protect against cpu-hotplug */
  		get_online_cpus();

  		cpuidle_pause_and_lock();

  
  		/* Disable all cpuidle devices */
  		for_each_online_cpu(cpu) {
  			_pr = per_cpu(processors, cpu);
  			if (!_pr || !_pr->flags.power_setup_done)
  				continue;

  			dev = per_cpu(acpi_cpuidle_device, cpu);
  			cpuidle_disable_device(dev);

  		}
  
  		/* Populate Updated C-state information */

  		acpi_processor_get_power_info(pr);

  		acpi_processor_setup_cpuidle_states(pr);
  
  		/* Enable all cpuidle devices */
  		for_each_online_cpu(cpu) {
  			_pr = per_cpu(processors, cpu);
  			if (!_pr || !_pr->flags.power_setup_done)
  				continue;
  			acpi_processor_get_power_info(_pr);
  			if (_pr->flags.power) {

  				dev = per_cpu(acpi_cpuidle_device, cpu);

  				acpi_processor_setup_cpuidle_dev(_pr, dev);

  				cpuidle_enable_device(dev);

  			}
  		}

  		cpuidle_resume_and_unlock();

  		put_online_cpus();

  	}
  
  	return 0;
  }
  
  static int acpi_processor_registered;

  int acpi_processor_power_init(struct acpi_processor *pr)

  {

  	int retval;

  	struct cpuidle_device *dev;

  	if (disabled_by_idle_boot_param())

  		return 0;

  	acpi_processor_cstate_first_run_checks();

  	if (!acpi_processor_get_power_info(pr))
  		pr->flags.power_setup_done = 1;

  
  	/*
  	 * Install the idle handler if processor power management is supported.
  	 * Note that we use previously set idle handler will be used on
  	 * platforms that only support C1.
  	 */

  	if (pr->flags.power) {

  		/* Register acpi_idle_driver if not already registered */
  		if (!acpi_processor_registered) {
  			acpi_processor_setup_cpuidle_states(pr);
  			retval = cpuidle_register_driver(&acpi_idle_driver);
  			if (retval)
  				return retval;

  			pr_debug("%s registered with cpuidle
  ",
  				 acpi_idle_driver.name);

  		}

  
  		dev = kzalloc(sizeof(*dev), GFP_KERNEL);
  		if (!dev)
  			return -ENOMEM;
  		per_cpu(acpi_cpuidle_device, pr->id) = dev;

  		acpi_processor_setup_cpuidle_dev(pr, dev);

  		/* Register per-cpu cpuidle_device. Cpuidle driver
  		 * must already be registered before registering device
  		 */

  		retval = cpuidle_register_device(dev);

  		if (retval) {
  			if (acpi_processor_registered == 0)
  				cpuidle_unregister_driver(&acpi_idle_driver);
  			return retval;
  		}
  		acpi_processor_registered++;

  	}

  	return 0;

  }

  int acpi_processor_power_exit(struct acpi_processor *pr)

  {

  	struct cpuidle_device *dev = per_cpu(acpi_cpuidle_device, pr->id);

  	if (disabled_by_idle_boot_param())

  		return 0;

  	if (pr->flags.power) {

  		cpuidle_unregister_device(dev);

  		acpi_processor_registered--;
  		if (acpi_processor_registered == 0)
  			cpuidle_unregister_driver(&acpi_idle_driver);
  	}

  	pr->flags.power_setup_done = 0;

  	return 0;

  }