perf top: Handle 'z' key for toggle zeroing samples in TUI

[linux-2.6/btrfs-unstable.git] / kernel / irq / chip.c

/*
 * linux/kernel/irq/chip.c
 *
 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
 *
 * This file contains the core interrupt handling code, for irq-chip
 * based architectures.
 *
 * Detailed information is available in Documentation/DocBook/genericirq
 */

#include <linux/irq.h>
#include <linux/msi.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>

#include <trace/events/irq.h>

#include "internals.h"

/**
 *      irq_set_chip - set the irq chip for an irq
 *      @irq:   irq number
 *      @chip:  pointer to irq chip description structure
 */
int irq_set_chip(unsigned int irq, struct irq_chip *chip)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);

        if (!desc)
                return -EINVAL;

        if (!chip)
                chip = &no_irq_chip;

        desc->irq_data.chip = chip;
        irq_put_desc_unlock(desc, flags);
        /*
         * For !CONFIG_SPARSE_IRQ make the irq show up in
         * allocated_irqs.
         */
        irq_mark_irq(irq);
        return 0;
}
EXPORT_SYMBOL(irq_set_chip);

/**
 *      irq_set_type - set the irq trigger type for an irq
 *      @irq:   irq number
 *      @type:  IRQ_TYPE_{LEVEL,EDGE}_* value - see include/linux/irq.h
 */
int irq_set_irq_type(unsigned int irq, unsigned int type)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
        int ret = 0;

        if (!desc)
                return -EINVAL;

        type &= IRQ_TYPE_SENSE_MASK;
        ret = __irq_set_trigger(desc, irq, type);
        irq_put_desc_busunlock(desc, flags);
        return ret;
}
EXPORT_SYMBOL(irq_set_irq_type);

/**
 *      irq_set_handler_data - set irq handler data for an irq
 *      @irq:   Interrupt number
 *      @data:  Pointer to interrupt specific data
 *
 *      Set the hardware irq controller data for an irq
 */
int irq_set_handler_data(unsigned int irq, void *data)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);

        if (!desc)
                return -EINVAL;
        desc->irq_data.handler_data = data;
        irq_put_desc_unlock(desc, flags);
        return 0;
}
EXPORT_SYMBOL(irq_set_handler_data);

/**
 *      irq_set_msi_desc_off - set MSI descriptor data for an irq at offset
 *      @irq_base:      Interrupt number base
 *      @irq_offset:    Interrupt number offset
 *      @entry:         Pointer to MSI descriptor data
 *
 *      Set the MSI descriptor entry for an irq at offset
 */
int irq_set_msi_desc_off(unsigned int irq_base, unsigned int irq_offset,
                         struct msi_desc *entry)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_lock(irq_base + irq_offset, &flags, IRQ_GET_DESC_CHECK_GLOBAL);

        if (!desc)
                return -EINVAL;
        desc->irq_data.msi_desc = entry;
        if (entry && !irq_offset)
                entry->irq = irq_base;
        irq_put_desc_unlock(desc, flags);
        return 0;
}

/**
 *      irq_set_msi_desc - set MSI descriptor data for an irq
 *      @irq:   Interrupt number
 *      @entry: Pointer to MSI descriptor data
 *
 *      Set the MSI descriptor entry for an irq
 */
int irq_set_msi_desc(unsigned int irq, struct msi_desc *entry)
{
        return irq_set_msi_desc_off(irq, 0, entry);
}

/**
 *      irq_set_chip_data - set irq chip data for an irq
 *      @irq:   Interrupt number
 *      @data:  Pointer to chip specific data
 *
 *      Set the hardware irq chip data for an irq
 */
int irq_set_chip_data(unsigned int irq, void *data)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);

        if (!desc)
                return -EINVAL;
        desc->irq_data.chip_data = data;
        irq_put_desc_unlock(desc, flags);
        return 0;
}
EXPORT_SYMBOL(irq_set_chip_data);

struct irq_data *irq_get_irq_data(unsigned int irq)
{
        struct irq_desc *desc = irq_to_desc(irq);

        return desc ? &desc->irq_data : NULL;
}
EXPORT_SYMBOL_GPL(irq_get_irq_data);

static void irq_state_clr_disabled(struct irq_desc *desc)
{
        irqd_clear(&desc->irq_data, IRQD_IRQ_DISABLED);
}

static void irq_state_set_disabled(struct irq_desc *desc)
{
        irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
}

static void irq_state_clr_masked(struct irq_desc *desc)
{
        irqd_clear(&desc->irq_data, IRQD_IRQ_MASKED);
}

static void irq_state_set_masked(struct irq_desc *desc)
{
        irqd_set(&desc->irq_data, IRQD_IRQ_MASKED);
}

int irq_startup(struct irq_desc *desc, bool resend)
{
        int ret = 0;

        irq_state_clr_disabled(desc);
        desc->depth = 0;

        if (desc->irq_data.chip->irq_startup) {
                ret = desc->irq_data.chip->irq_startup(&desc->irq_data);
                irq_state_clr_masked(desc);
        } else {
                irq_enable(desc);
        }
        if (resend)
                check_irq_resend(desc, desc->irq_data.irq);
        return ret;
}

void irq_shutdown(struct irq_desc *desc)
{
        irq_state_set_disabled(desc);
        desc->depth = 1;
        if (desc->irq_data.chip->irq_shutdown)
                desc->irq_data.chip->irq_shutdown(&desc->irq_data);
        else if (desc->irq_data.chip->irq_disable)
                desc->irq_data.chip->irq_disable(&desc->irq_data);
        else
                desc->irq_data.chip->irq_mask(&desc->irq_data);
        irq_state_set_masked(desc);
}

void irq_enable(struct irq_desc *desc)
{
        irq_state_clr_disabled(desc);
        if (desc->irq_data.chip->irq_enable)
                desc->irq_data.chip->irq_enable(&desc->irq_data);
        else
                desc->irq_data.chip->irq_unmask(&desc->irq_data);
        irq_state_clr_masked(desc);
}

/**
 * irq_disable - Mark interrupt disabled
 * @desc:       irq descriptor which should be disabled
 *
 * If the chip does not implement the irq_disable callback, we
 * use a lazy disable approach. That means we mark the interrupt
 * disabled, but leave the hardware unmasked. That's an
 * optimization because we avoid the hardware access for the
 * common case where no interrupt happens after we marked it
 * disabled. If an interrupt happens, then the interrupt flow
 * handler masks the line at the hardware level and marks it
 * pending.
 */
void irq_disable(struct irq_desc *desc)
{
        irq_state_set_disabled(desc);
        if (desc->irq_data.chip->irq_disable) {
                desc->irq_data.chip->irq_disable(&desc->irq_data);
                irq_state_set_masked(desc);
        }
}

void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu)
{
        if (desc->irq_data.chip->irq_enable)
                desc->irq_data.chip->irq_enable(&desc->irq_data);
        else
                desc->irq_data.chip->irq_unmask(&desc->irq_data);
        cpumask_set_cpu(cpu, desc->percpu_enabled);
}

void irq_percpu_disable(struct irq_desc *desc, unsigned int cpu)
{
        if (desc->irq_data.chip->irq_disable)
                desc->irq_data.chip->irq_disable(&desc->irq_data);
        else
                desc->irq_data.chip->irq_mask(&desc->irq_data);
        cpumask_clear_cpu(cpu, desc->percpu_enabled);
}

static inline void mask_ack_irq(struct irq_desc *desc)
{
        if (desc->irq_data.chip->irq_mask_ack)
                desc->irq_data.chip->irq_mask_ack(&desc->irq_data);
        else {
                desc->irq_data.chip->irq_mask(&desc->irq_data);
                if (desc->irq_data.chip->irq_ack)
                        desc->irq_data.chip->irq_ack(&desc->irq_data);
        }
        irq_state_set_masked(desc);
}

void mask_irq(struct irq_desc *desc)
{
        if (desc->irq_data.chip->irq_mask) {
                desc->irq_data.chip->irq_mask(&desc->irq_data);
                irq_state_set_masked(desc);
        }
}

void unmask_irq(struct irq_desc *desc)
{
        if (desc->irq_data.chip->irq_unmask) {
                desc->irq_data.chip->irq_unmask(&desc->irq_data);
                irq_state_clr_masked(desc);
        }
}

void unmask_threaded_irq(struct irq_desc *desc)
{
        struct irq_chip *chip = desc->irq_data.chip;

        if (chip->flags & IRQCHIP_EOI_THREADED)
                chip->irq_eoi(&desc->irq_data);

        if (chip->irq_unmask) {
                chip->irq_unmask(&desc->irq_data);
                irq_state_clr_masked(desc);
        }
}

/*
 *      handle_nested_irq - Handle a nested irq from a irq thread
 *      @irq:   the interrupt number
 *
 *      Handle interrupts which are nested into a threaded interrupt
 *      handler. The handler function is called inside the calling
 *      threads context.
 */
void handle_nested_irq(unsigned int irq)
{
        struct irq_desc *desc = irq_to_desc(irq);
        struct irqaction *action;
        irqreturn_t action_ret;

        might_sleep();

        raw_spin_lock_irq(&desc->lock);

        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
        kstat_incr_irqs_this_cpu(irq, desc);

        action = desc->action;
        if (unlikely(!action || irqd_irq_disabled(&desc->irq_data))) {
                desc->istate |= IRQS_PENDING;
                goto out_unlock;
        }

        irqd_set(&desc->irq_data, IRQD_IRQ_INPROGRESS);
        raw_spin_unlock_irq(&desc->lock);

        action_ret = action->thread_fn(action->irq, action->dev_id);
        if (!noirqdebug)
                note_interrupt(irq, desc, action_ret);

        raw_spin_lock_irq(&desc->lock);
        irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);

out_unlock:
        raw_spin_unlock_irq(&desc->lock);
}
EXPORT_SYMBOL_GPL(handle_nested_irq);

static bool irq_check_poll(struct irq_desc *desc)
{
        if (!(desc->istate & IRQS_POLL_INPROGRESS))
                return false;
        return irq_wait_for_poll(desc);
}

/**
 *      handle_simple_irq - Simple and software-decoded IRQs.
 *      @irq:   the interrupt number
 *      @desc:  the interrupt description structure for this irq
 *
 *      Simple interrupts are either sent from a demultiplexing interrupt
 *      handler or come from hardware, where no interrupt hardware control
 *      is necessary.
 *
 *      Note: The caller is expected to handle the ack, clear, mask and
 *      unmask issues if necessary.
 */
void
handle_simple_irq(unsigned int irq, struct irq_desc *desc)
{
        raw_spin_lock(&desc->lock);

        if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
                if (!irq_check_poll(desc))
                        goto out_unlock;

        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
        kstat_incr_irqs_this_cpu(irq, desc);

        if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
                desc->istate |= IRQS_PENDING;
                goto out_unlock;
        }

        handle_irq_event(desc);

out_unlock:
        raw_spin_unlock(&desc->lock);
}
EXPORT_SYMBOL_GPL(handle_simple_irq);

/*
 * Called unconditionally from handle_level_irq() and only for oneshot
 * interrupts from handle_fasteoi_irq()
 */
static void cond_unmask_irq(struct irq_desc *desc)
{
        /*
         * We need to unmask in the following cases:
         * - Standard level irq (IRQF_ONESHOT is not set)
         * - Oneshot irq which did not wake the thread (caused by a
         *   spurious interrupt or a primary handler handling it
         *   completely).
         */
        if (!irqd_irq_disabled(&desc->irq_data) &&
            irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot)
                unmask_irq(desc);
}

/**
 *      handle_level_irq - Level type irq handler
 *      @irq:   the interrupt number
 *      @desc:  the interrupt description structure for this irq
 *
 *      Level type interrupts are active as long as the hardware line has
 *      the active level. This may require to mask the interrupt and unmask
 *      it after the associated handler has acknowledged the device, so the
 *      interrupt line is back to inactive.
 */
void
handle_level_irq(unsigned int irq, struct irq_desc *desc)
{
        raw_spin_lock(&desc->lock);
        mask_ack_irq(desc);

        if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
                if (!irq_check_poll(desc))
                        goto out_unlock;

        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
        kstat_incr_irqs_this_cpu(irq, desc);

        /*
         * If its disabled or no action available
         * keep it masked and get out of here
         */
        if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
                desc->istate |= IRQS_PENDING;
                goto out_unlock;
        }

        handle_irq_event(desc);

        cond_unmask_irq(desc);

out_unlock:
        raw_spin_unlock(&desc->lock);
}
EXPORT_SYMBOL_GPL(handle_level_irq);

#ifdef CONFIG_IRQ_PREFLOW_FASTEOI
static inline void preflow_handler(struct irq_desc *desc)
{
        if (desc->preflow_handler)
                desc->preflow_handler(&desc->irq_data);
}
#else
static inline void preflow_handler(struct irq_desc *desc) { }
#endif

static void cond_unmask_eoi_irq(struct irq_desc *desc, struct irq_chip *chip)
{
        if (!(desc->istate & IRQS_ONESHOT)) {
                chip->irq_eoi(&desc->irq_data);
                return;
        }
        /*
         * We need to unmask in the following cases:
         * - Oneshot irq which did not wake the thread (caused by a
         *   spurious interrupt or a primary handler handling it
         *   completely).
         */
        if (!irqd_irq_disabled(&desc->irq_data) &&
            irqd_irq_masked(&desc->irq_data) && !desc->threads_oneshot) {
                chip->irq_eoi(&desc->irq_data);
                unmask_irq(desc);
        } else if (!(chip->flags & IRQCHIP_EOI_THREADED)) {
                chip->irq_eoi(&desc->irq_data);
        }
}

/**
 *      handle_fasteoi_irq - irq handler for transparent controllers
 *      @irq:   the interrupt number
 *      @desc:  the interrupt description structure for this irq
 *
 *      Only a single callback will be issued to the chip: an ->eoi()
 *      call when the interrupt has been serviced. This enables support
 *      for modern forms of interrupt handlers, which handle the flow
 *      details in hardware, transparently.
 */
void
handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
{
        struct irq_chip *chip = desc->irq_data.chip;

        raw_spin_lock(&desc->lock);

        if (unlikely(irqd_irq_inprogress(&desc->irq_data)))
                if (!irq_check_poll(desc))
                        goto out;

        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
        kstat_incr_irqs_this_cpu(irq, desc);

        /*
         * If its disabled or no action available
         * then mask it and get out of here:
         */
        if (unlikely(!desc->action || irqd_irq_disabled(&desc->irq_data))) {
                desc->istate |= IRQS_PENDING;
                mask_irq(desc);
                goto out;
        }

        if (desc->istate & IRQS_ONESHOT)
                mask_irq(desc);

        preflow_handler(desc);
        handle_irq_event(desc);

        cond_unmask_eoi_irq(desc, chip);

        raw_spin_unlock(&desc->lock);
        return;
out:
        if (!(chip->flags & IRQCHIP_EOI_IF_HANDLED))
                chip->irq_eoi(&desc->irq_data);
        raw_spin_unlock(&desc->lock);
}

/**
 *      handle_edge_irq - edge type IRQ handler
 *      @irq:   the interrupt number
 *      @desc:  the interrupt description structure for this irq
 *
 *      Interrupt occures on the falling and/or rising edge of a hardware
 *      signal. The occurrence is latched into the irq controller hardware
 *      and must be acked in order to be reenabled. After the ack another
 *      interrupt can happen on the same source even before the first one
 *      is handled by the associated event handler. If this happens it
 *      might be necessary to disable (mask) the interrupt depending on the
 *      controller hardware. This requires to reenable the interrupt inside
 *      of the loop which handles the interrupts which have arrived while
 *      the handler was running. If all pending interrupts are handled, the
 *      loop is left.
 */
void
handle_edge_irq(unsigned int irq, struct irq_desc *desc)
{
        raw_spin_lock(&desc->lock);

        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
        /*
         * If we're currently running this IRQ, or its disabled,
         * we shouldn't process the IRQ. Mark it pending, handle
         * the necessary masking and go out
         */
        if (unlikely(irqd_irq_disabled(&desc->irq_data) ||
                     irqd_irq_inprogress(&desc->irq_data) || !desc->action)) {
                if (!irq_check_poll(desc)) {
                        desc->istate |= IRQS_PENDING;
                        mask_ack_irq(desc);
                        goto out_unlock;
                }
        }
        kstat_incr_irqs_this_cpu(irq, desc);

        /* Start handling the irq */
        desc->irq_data.chip->irq_ack(&desc->irq_data);

        do {
                if (unlikely(!desc->action)) {
                        mask_irq(desc);
                        goto out_unlock;
                }

                /*
                 * When another irq arrived while we were handling
                 * one, we could have masked the irq.
                 * Renable it, if it was not disabled in meantime.
                 */
                if (unlikely(desc->istate & IRQS_PENDING)) {
                        if (!irqd_irq_disabled(&desc->irq_data) &&
                            irqd_irq_masked(&desc->irq_data))
                                unmask_irq(desc);
                }

                handle_irq_event(desc);

        } while ((desc->istate & IRQS_PENDING) &&
                 !irqd_irq_disabled(&desc->irq_data));

out_unlock:
        raw_spin_unlock(&desc->lock);
}
EXPORT_SYMBOL(handle_edge_irq);

#ifdef CONFIG_IRQ_EDGE_EOI_HANDLER
/**
 *      handle_edge_eoi_irq - edge eoi type IRQ handler
 *      @irq:   the interrupt number
 *      @desc:  the interrupt description structure for this irq
 *
 * Similar as the above handle_edge_irq, but using eoi and w/o the
 * mask/unmask logic.
 */
void handle_edge_eoi_irq(unsigned int irq, struct irq_desc *desc)
{
        struct irq_chip *chip = irq_desc_get_chip(desc);

        raw_spin_lock(&desc->lock);

        desc->istate &= ~(IRQS_REPLAY | IRQS_WAITING);
        /*
         * If we're currently running this IRQ, or its disabled,
         * we shouldn't process the IRQ. Mark it pending, handle
         * the necessary masking and go out
         */
        if (unlikely(irqd_irq_disabled(&desc->irq_data) ||
                     irqd_irq_inprogress(&desc->irq_data) || !desc->action)) {
                if (!irq_check_poll(desc)) {
                        desc->istate |= IRQS_PENDING;
                        goto out_eoi;
                }
        }
        kstat_incr_irqs_this_cpu(irq, desc);

        do {
                if (unlikely(!desc->action))
                        goto out_eoi;

                handle_irq_event(desc);

        } while ((desc->istate & IRQS_PENDING) &&
                 !irqd_irq_disabled(&desc->irq_data));

out_eoi:
        chip->irq_eoi(&desc->irq_data);
        raw_spin_unlock(&desc->lock);
}
#endif

/**
 *      handle_percpu_irq - Per CPU local irq handler
 *      @irq:   the interrupt number
 *      @desc:  the interrupt description structure for this irq
 *
 *      Per CPU interrupts on SMP machines without locking requirements
 */
void
handle_percpu_irq(unsigned int irq, struct irq_desc *desc)
{
        struct irq_chip *chip = irq_desc_get_chip(desc);

        kstat_incr_irqs_this_cpu(irq, desc);

        if (chip->irq_ack)
                chip->irq_ack(&desc->irq_data);

        handle_irq_event_percpu(desc, desc->action);

        if (chip->irq_eoi)
                chip->irq_eoi(&desc->irq_data);
}

/**
 * handle_percpu_devid_irq - Per CPU local irq handler with per cpu dev ids
 * @irq:        the interrupt number
 * @desc:       the interrupt description structure for this irq
 *
 * Per CPU interrupts on SMP machines without locking requirements. Same as
 * handle_percpu_irq() above but with the following extras:
 *
 * action->percpu_dev_id is a pointer to percpu variables which
 * contain the real device id for the cpu on which this handler is
 * called
 */
void handle_percpu_devid_irq(unsigned int irq, struct irq_desc *desc)
{
        struct irq_chip *chip = irq_desc_get_chip(desc);
        struct irqaction *action = desc->action;
        void *dev_id = __this_cpu_ptr(action->percpu_dev_id);
        irqreturn_t res;

        kstat_incr_irqs_this_cpu(irq, desc);

        if (chip->irq_ack)
                chip->irq_ack(&desc->irq_data);

        trace_irq_handler_entry(irq, action);
        res = action->handler(irq, dev_id);
        trace_irq_handler_exit(irq, action, res);

        if (chip->irq_eoi)
                chip->irq_eoi(&desc->irq_data);
}

void
__irq_set_handler(unsigned int irq, irq_flow_handler_t handle, int is_chained,
                  const char *name)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, 0);

        if (!desc)
                return;

        if (!handle) {
                handle = handle_bad_irq;
        } else {
                if (WARN_ON(desc->irq_data.chip == &no_irq_chip))
                        goto out;
        }

        /* Uninstall? */
        if (handle == handle_bad_irq) {
                if (desc->irq_data.chip != &no_irq_chip)
                        mask_ack_irq(desc);
                irq_state_set_disabled(desc);
                desc->depth = 1;
        }
        desc->handle_irq = handle;
        desc->name = name;

        if (handle != handle_bad_irq && is_chained) {
                irq_settings_set_noprobe(desc);
                irq_settings_set_norequest(desc);
                irq_settings_set_nothread(desc);
                irq_startup(desc, true);
        }
out:
        irq_put_desc_busunlock(desc, flags);
}
EXPORT_SYMBOL_GPL(__irq_set_handler);

void
irq_set_chip_and_handler_name(unsigned int irq, struct irq_chip *chip,
                              irq_flow_handler_t handle, const char *name)
{
        irq_set_chip(irq, chip);
        __irq_set_handler(irq, handle, 0, name);
}
EXPORT_SYMBOL_GPL(irq_set_chip_and_handler_name);

void irq_modify_status(unsigned int irq, unsigned long clr, unsigned long set)
{
        unsigned long flags;
        struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);

        if (!desc)
                return;
        irq_settings_clr_and_set(desc, clr, set);

        irqd_clear(&desc->irq_data, IRQD_NO_BALANCING | IRQD_PER_CPU |
                   IRQD_TRIGGER_MASK | IRQD_LEVEL | IRQD_MOVE_PCNTXT);
        if (irq_settings_has_no_balance_set(desc))
                irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
        if (irq_settings_is_per_cpu(desc))
                irqd_set(&desc->irq_data, IRQD_PER_CPU);
        if (irq_settings_can_move_pcntxt(desc))
                irqd_set(&desc->irq_data, IRQD_MOVE_PCNTXT);
        if (irq_settings_is_level(desc))
                irqd_set(&desc->irq_data, IRQD_LEVEL);

        irqd_set(&desc->irq_data, irq_settings_get_trigger_mask(desc));

        irq_put_desc_unlock(desc, flags);
}
EXPORT_SYMBOL_GPL(irq_modify_status);

/**
 *      irq_cpu_online - Invoke all irq_cpu_online functions.
 *
 *      Iterate through all irqs and invoke the chip.irq_cpu_online()
 *      for each.
 */
void irq_cpu_online(void)
{
        struct irq_desc *desc;
        struct irq_chip *chip;
        unsigned long flags;
        unsigned int irq;

        for_each_active_irq(irq) {
                desc = irq_to_desc(irq);
                if (!desc)
                        continue;

                raw_spin_lock_irqsave(&desc->lock, flags);

                chip = irq_data_get_irq_chip(&desc->irq_data);
                if (chip && chip->irq_cpu_online &&
                    (!(chip->flags & IRQCHIP_ONOFFLINE_ENABLED) ||
                     !irqd_irq_disabled(&desc->irq_data)))
                        chip->irq_cpu_online(&desc->irq_data);

                raw_spin_unlock_irqrestore(&desc->lock, flags);
        }
}

/**
 *      irq_cpu_offline - Invoke all irq_cpu_offline functions.
 *
 *      Iterate through all irqs and invoke the chip.irq_cpu_offline()
 *      for each.
 */
void irq_cpu_offline(void)
{
        struct irq_desc *desc;
        struct irq_chip *chip;
        unsigned long flags;
        unsigned int irq;

        for_each_active_irq(irq) {
                desc = irq_to_desc(irq);
                if (!desc)
                        continue;

                raw_spin_lock_irqsave(&desc->lock, flags);

                chip = irq_data_get_irq_chip(&desc->irq_data);
                if (chip && chip->irq_cpu_offline &&
                    (!(chip->flags & IRQCHIP_ONOFFLINE_ENABLED) ||
                     !irqd_irq_disabled(&desc->irq_data)))
                        chip->irq_cpu_offline(&desc->irq_data);

                raw_spin_unlock_irqrestore(&desc->lock, flags);
        }
}