--- /dev/null
+/*
+ * linux/kernel/irq/manage.c
+ *
+ * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
+ * Copyright (C) 2005-2006 Thomas Gleixner
+ *
+ * This file contains driver APIs to the irq subsystem.
+ */
+
+#define pr_fmt(fmt) "genirq: " fmt
+
+#include <linux/irq.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/sched/rt.h>
+#include <linux/task_work.h>
+
+#include "internals.h"
+
+#ifdef CONFIG_IRQ_FORCED_THREADING
+# ifndef CONFIG_PREEMPT_RT_BASE
+__read_mostly bool force_irqthreads;
+
+static int __init setup_forced_irqthreads(char *arg)
+{
+ force_irqthreads = true;
+ return 0;
+}
+early_param("threadirqs", setup_forced_irqthreads);
+# endif
+#endif
+
+static void __synchronize_hardirq(struct irq_desc *desc)
+{
+ bool inprogress;
+
+ do {
+ unsigned long flags;
+
+ /*
+ * Wait until we're out of the critical section. This might
+ * give the wrong answer due to the lack of memory barriers.
+ */
+ while (irqd_irq_inprogress(&desc->irq_data))
+ cpu_relax();
+
+ /* Ok, that indicated we're done: double-check carefully. */
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ inprogress = irqd_irq_inprogress(&desc->irq_data);
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ /* Oops, that failed? */
+ } while (inprogress);
+}
+
+/**
+ * synchronize_hardirq - wait for pending hard IRQ handlers (on other CPUs)
+ * @irq: interrupt number to wait for
+ *
+ * This function waits for any pending hard IRQ handlers for this
+ * interrupt to complete before returning. If you use this
+ * function while holding a resource the IRQ handler may need you
+ * will deadlock. It does not take associated threaded handlers
+ * into account.
+ *
+ * Do not use this for shutdown scenarios where you must be sure
+ * that all parts (hardirq and threaded handler) have completed.
+ *
+ * Returns: false if a threaded handler is active.
+ *
+ * This function may be called - with care - from IRQ context.
+ */
+bool synchronize_hardirq(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (desc) {
+ __synchronize_hardirq(desc);
+ return !atomic_read(&desc->threads_active);
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(synchronize_hardirq);
+
+/**
+ * synchronize_irq - wait for pending IRQ handlers (on other CPUs)
+ * @irq: interrupt number to wait for
+ *
+ * This function waits for any pending IRQ handlers for this interrupt
+ * to complete before returning. If you use this function while
+ * holding a resource the IRQ handler may need you will deadlock.
+ *
+ * This function may be called - with care - from IRQ context.
+ */
+void synchronize_irq(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (desc) {
+ __synchronize_hardirq(desc);
+ /*
+ * We made sure that no hardirq handler is
+ * running. Now verify that no threaded handlers are
+ * active.
+ */
+ wait_event(desc->wait_for_threads,
+ !atomic_read(&desc->threads_active));
+ }
+}
+EXPORT_SYMBOL(synchronize_irq);
+
+#ifdef CONFIG_SMP
+cpumask_var_t irq_default_affinity;
+
+/**
+ * irq_can_set_affinity - Check if the affinity of a given irq can be set
+ * @irq: Interrupt to check
+ *
+ */
+int irq_can_set_affinity(unsigned int irq)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (!desc || !irqd_can_balance(&desc->irq_data) ||
+ !desc->irq_data.chip || !desc->irq_data.chip->irq_set_affinity)
+ return 0;
+
+ return 1;
+}
+
+/**
+ * irq_set_thread_affinity - Notify irq threads to adjust affinity
+ * @desc: irq descriptor which has affitnity changed
+ *
+ * We just set IRQTF_AFFINITY and delegate the affinity setting
+ * to the interrupt thread itself. We can not call
+ * set_cpus_allowed_ptr() here as we hold desc->lock and this
+ * code can be called from hard interrupt context.
+ */
+void irq_set_thread_affinity(struct irq_desc *desc)
+{
+ struct irqaction *action = desc->action;
+
+ while (action) {
+ if (action->thread)
+ set_bit(IRQTF_AFFINITY, &action->thread_flags);
+ action = action->next;
+ }
+}
+
+#ifdef CONFIG_GENERIC_PENDING_IRQ
+static inline bool irq_can_move_pcntxt(struct irq_data *data)
+{
+ return irqd_can_move_in_process_context(data);
+}
+static inline bool irq_move_pending(struct irq_data *data)
+{
+ return irqd_is_setaffinity_pending(data);
+}
+static inline void
+irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask)
+{
+ cpumask_copy(desc->pending_mask, mask);
+}
+static inline void
+irq_get_pending(struct cpumask *mask, struct irq_desc *desc)
+{
+ cpumask_copy(mask, desc->pending_mask);
+}
+#else
+static inline bool irq_can_move_pcntxt(struct irq_data *data) { return true; }
+static inline bool irq_move_pending(struct irq_data *data) { return false; }
+static inline void
+irq_copy_pending(struct irq_desc *desc, const struct cpumask *mask) { }
+static inline void
+irq_get_pending(struct cpumask *mask, struct irq_desc *desc) { }
+#endif
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+static void _irq_affinity_notify(struct irq_affinity_notify *notify);
+static struct task_struct *set_affinity_helper;
+static LIST_HEAD(affinity_list);
+static DEFINE_RAW_SPINLOCK(affinity_list_lock);
+
+static int set_affinity_thread(void *unused)
+{
+ while (1) {
+ struct irq_affinity_notify *notify;
+ int empty;
+
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ raw_spin_lock_irq(&affinity_list_lock);
+ empty = list_empty(&affinity_list);
+ raw_spin_unlock_irq(&affinity_list_lock);
+
+ if (empty)
+ schedule();
+ if (kthread_should_stop())
+ break;
+ set_current_state(TASK_RUNNING);
+try_next:
+ notify = NULL;
+
+ raw_spin_lock_irq(&affinity_list_lock);
+ if (!list_empty(&affinity_list)) {
+ notify = list_first_entry(&affinity_list,
+ struct irq_affinity_notify, list);
+ list_del_init(¬ify->list);
+ }
+ raw_spin_unlock_irq(&affinity_list_lock);
+
+ if (!notify)
+ continue;
+ _irq_affinity_notify(notify);
+ goto try_next;
+ }
+ return 0;
+}
+
+static void init_helper_thread(void)
+{
+ if (set_affinity_helper)
+ return;
+ set_affinity_helper = kthread_run(set_affinity_thread, NULL,
+ "affinity-cb");
+ WARN_ON(IS_ERR(set_affinity_helper));
+}
+#else
+
+static inline void init_helper_thread(void) { }
+
+#endif
+
+int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
+ bool force)
+{
+ struct irq_desc *desc = irq_data_to_desc(data);
+ struct irq_chip *chip = irq_data_get_irq_chip(data);
+ int ret;
+
+ ret = chip->irq_set_affinity(data, mask, force);
+ switch (ret) {
+ case IRQ_SET_MASK_OK:
+ case IRQ_SET_MASK_OK_DONE:
+ cpumask_copy(data->affinity, mask);
+ case IRQ_SET_MASK_OK_NOCOPY:
+ irq_set_thread_affinity(desc);
+ ret = 0;
+ }
+
+ return ret;
+}
+
+int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
+ bool force)
+{
+ struct irq_chip *chip = irq_data_get_irq_chip(data);
+ struct irq_desc *desc = irq_data_to_desc(data);
+ int ret = 0;
+
+ if (!chip || !chip->irq_set_affinity)
+ return -EINVAL;
+
+ if (irq_can_move_pcntxt(data)) {
+ ret = irq_do_set_affinity(data, mask, force);
+ } else {
+ irqd_set_move_pending(data);
+ irq_copy_pending(desc, mask);
+ }
+
+ if (desc->affinity_notify) {
+ kref_get(&desc->affinity_notify->kref);
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+ raw_spin_lock(&affinity_list_lock);
+ if (list_empty(&desc->affinity_notify->list))
+ list_add_tail(&affinity_list,
+ &desc->affinity_notify->list);
+ raw_spin_unlock(&affinity_list_lock);
+ wake_up_process(set_affinity_helper);
+#else
+ schedule_work(&desc->affinity_notify->work);
+#endif
+ }
+ irqd_set(data, IRQD_AFFINITY_SET);
+
+ return ret;
+}
+
+int __irq_set_affinity(unsigned int irq, const struct cpumask *mask, bool force)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ unsigned long flags;
+ int ret;
+
+ if (!desc)
+ return -EINVAL;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ ret = irq_set_affinity_locked(irq_desc_get_irq_data(desc), mask, force);
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+ return ret;
+}
+
+int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+ if (!desc)
+ return -EINVAL;
+ desc->affinity_hint = m;
+ irq_put_desc_unlock(desc, flags);
+ /* set the initial affinity to prevent every interrupt being on CPU0 */
+ if (m)
+ __irq_set_affinity(irq, m, false);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(irq_set_affinity_hint);
+
+static void _irq_affinity_notify(struct irq_affinity_notify *notify)
+{
+ struct irq_desc *desc = irq_to_desc(notify->irq);
+ cpumask_var_t cpumask;
+ unsigned long flags;
+
+ if (!desc || !alloc_cpumask_var(&cpumask, GFP_KERNEL))
+ goto out;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ if (irq_move_pending(&desc->irq_data))
+ irq_get_pending(cpumask, desc);
+ else
+ cpumask_copy(cpumask, desc->irq_data.affinity);
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ notify->notify(notify, cpumask);
+
+ free_cpumask_var(cpumask);
+out:
+ kref_put(¬ify->kref, notify->release);
+}
+
+static void irq_affinity_notify(struct work_struct *work)
+{
+ struct irq_affinity_notify *notify =
+ container_of(work, struct irq_affinity_notify, work);
+ _irq_affinity_notify(notify);
+}
+
+/**
+ * irq_set_affinity_notifier - control notification of IRQ affinity changes
+ * @irq: Interrupt for which to enable/disable notification
+ * @notify: Context for notification, or %NULL to disable
+ * notification. Function pointers must be initialised;
+ * the other fields will be initialised by this function.
+ *
+ * Must be called in process context. Notification may only be enabled
+ * after the IRQ is allocated and must be disabled before the IRQ is
+ * freed using free_irq().
+ */
+int
+irq_set_affinity_notifier(unsigned int irq, struct irq_affinity_notify *notify)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct irq_affinity_notify *old_notify;
+ unsigned long flags;
+
+ /* The release function is promised process context */
+ might_sleep();
+
+ if (!desc)
+ return -EINVAL;
+
+ /* Complete initialisation of *notify */
+ if (notify) {
+ notify->irq = irq;
+ kref_init(¬ify->kref);
+ INIT_WORK(¬ify->work, irq_affinity_notify);
+ INIT_LIST_HEAD(¬ify->list);
+ init_helper_thread();
+ }
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ old_notify = desc->affinity_notify;
+ desc->affinity_notify = notify;
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ if (old_notify)
+ kref_put(&old_notify->kref, old_notify->release);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(irq_set_affinity_notifier);
+
+#ifndef CONFIG_AUTO_IRQ_AFFINITY
+/*
+ * Generic version of the affinity autoselector.
+ */
+static int
+setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
+{
+ struct cpumask *set = irq_default_affinity;
+ int node = desc->irq_data.node;
+
+ /* Excludes PER_CPU and NO_BALANCE interrupts */
+ if (!irq_can_set_affinity(irq))
+ return 0;
+
+ /*
+ * Preserve an userspace affinity setup, but make sure that
+ * one of the targets is online.
+ */
+ if (irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
+ if (cpumask_intersects(desc->irq_data.affinity,
+ cpu_online_mask))
+ set = desc->irq_data.affinity;
+ else
+ irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
+ }
+
+ cpumask_and(mask, cpu_online_mask, set);
+ if (node != NUMA_NO_NODE) {
+ const struct cpumask *nodemask = cpumask_of_node(node);
+
+ /* make sure at least one of the cpus in nodemask is online */
+ if (cpumask_intersects(mask, nodemask))
+ cpumask_and(mask, mask, nodemask);
+ }
+ irq_do_set_affinity(&desc->irq_data, mask, false);
+ return 0;
+}
+#else
+static inline int
+setup_affinity(unsigned int irq, struct irq_desc *d, struct cpumask *mask)
+{
+ return irq_select_affinity(irq);
+}
+#endif
+
+/*
+ * Called when affinity is set via /proc/irq
+ */
+int irq_select_affinity_usr(unsigned int irq, struct cpumask *mask)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ unsigned long flags;
+ int ret;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ ret = setup_affinity(irq, desc, mask);
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+ return ret;
+}
+
+#else
+static inline int
+setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask)
+{
+ return 0;
+}
+#endif
+
+void __disable_irq(struct irq_desc *desc, unsigned int irq)
+{
+ if (!desc->depth++)
+ irq_disable(desc);
+}
+
+static int __disable_irq_nosync(unsigned int irq)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+ if (!desc)
+ return -EINVAL;
+ __disable_irq(desc, irq);
+ irq_put_desc_busunlock(desc, flags);
+ return 0;
+}
+
+/**
+ * disable_irq_nosync - disable an irq without waiting
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Disables and Enables are
+ * nested.
+ * Unlike disable_irq(), this function does not ensure existing
+ * instances of the IRQ handler have completed before returning.
+ *
+ * This function may be called from IRQ context.
+ */
+void disable_irq_nosync(unsigned int irq)
+{
+ __disable_irq_nosync(irq);
+}
+EXPORT_SYMBOL(disable_irq_nosync);
+
+/**
+ * disable_irq - disable an irq and wait for completion
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Enables and Disables are
+ * nested.
+ * This function waits for any pending IRQ handlers for this interrupt
+ * to complete before returning. If you use this function while
+ * holding a resource the IRQ handler may need you will deadlock.
+ *
+ * This function may be called - with care - from IRQ context.
+ */
+void disable_irq(unsigned int irq)
+{
+ if (!__disable_irq_nosync(irq))
+ synchronize_irq(irq);
+}
+EXPORT_SYMBOL(disable_irq);
+
+/**
+ * disable_hardirq - disables an irq and waits for hardirq completion
+ * @irq: Interrupt to disable
+ *
+ * Disable the selected interrupt line. Enables and Disables are
+ * nested.
+ * This function waits for any pending hard IRQ handlers for this
+ * interrupt to complete before returning. If you use this function while
+ * holding a resource the hard IRQ handler may need you will deadlock.
+ *
+ * When used to optimistically disable an interrupt from atomic context
+ * the return value must be checked.
+ *
+ * Returns: false if a threaded handler is active.
+ *
+ * This function may be called - with care - from IRQ context.
+ */
+bool disable_hardirq(unsigned int irq)
+{
+ if (!__disable_irq_nosync(irq))
+ return synchronize_hardirq(irq);
+
+ return false;
+}
+EXPORT_SYMBOL_GPL(disable_hardirq);
+
+void __enable_irq(struct irq_desc *desc, unsigned int irq)
+{
+ switch (desc->depth) {
+ case 0:
+ err_out:
+ WARN(1, KERN_WARNING "Unbalanced enable for IRQ %d\n", irq);
+ break;
+ case 1: {
+ if (desc->istate & IRQS_SUSPENDED)
+ goto err_out;
+ /* Prevent probing on this irq: */
+ irq_settings_set_noprobe(desc);
+ irq_enable(desc);
+ check_irq_resend(desc, irq);
+ /* fall-through */
+ }
+ default:
+ desc->depth--;
+ }
+}
+
+/**
+ * enable_irq - enable handling of an irq
+ * @irq: Interrupt to enable
+ *
+ * Undoes the effect of one call to disable_irq(). If this
+ * matches the last disable, processing of interrupts on this
+ * IRQ line is re-enabled.
+ *
+ * This function may be called from IRQ context only when
+ * desc->irq_data.chip->bus_lock and desc->chip->bus_sync_unlock are NULL !
+ */
+void enable_irq(unsigned int irq)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_buslock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL);
+
+ if (!desc)
+ return;
+ if (WARN(!desc->irq_data.chip,
+ KERN_ERR "enable_irq before setup/request_irq: irq %u\n", irq))
+ goto out;
+
+ __enable_irq(desc, irq);
+out:
+ irq_put_desc_busunlock(desc, flags);
+}
+EXPORT_SYMBOL(enable_irq);
+
+static int set_irq_wake_real(unsigned int irq, unsigned int on)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ int ret = -ENXIO;
+
+ if (irq_desc_get_chip(desc)->flags & IRQCHIP_SKIP_SET_WAKE)
+ return 0;
+
+ if (desc->irq_data.chip->irq_set_wake)
+ ret = desc->irq_data.chip->irq_set_wake(&desc->irq_data, on);
+
+ return ret;
+}
+
+/**
+ * irq_set_irq_wake - control irq power management wakeup
+ * @irq: interrupt to control
+ * @on: enable/disable power management wakeup
+ *
+ * Enable/disable power management wakeup mode, which is
+ * disabled by default. Enables and disables must match,
+ * just as they match for non-wakeup mode support.
+ *
+ * Wakeup mode lets this IRQ wake the system from sleep
+ * states like "suspend to RAM".
+ */
+int irq_set_irq_wake(unsigned int irq, unsigned int on)
+{
+ 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;
+
+ /* wakeup-capable irqs can be shared between drivers that
+ * don't need to have the same sleep mode behaviors.
+ */
+ if (on) {
+ if (desc->wake_depth++ == 0) {
+ ret = set_irq_wake_real(irq, on);
+ if (ret)
+ desc->wake_depth = 0;
+ else
+ irqd_set(&desc->irq_data, IRQD_WAKEUP_STATE);
+ }
+ } else {
+ if (desc->wake_depth == 0) {
+ WARN(1, "Unbalanced IRQ %d wake disable\n", irq);
+ } else if (--desc->wake_depth == 0) {
+ ret = set_irq_wake_real(irq, on);
+ if (ret)
+ desc->wake_depth = 1;
+ else
+ irqd_clear(&desc->irq_data, IRQD_WAKEUP_STATE);
+ }
+ }
+ irq_put_desc_busunlock(desc, flags);
+ return ret;
+}
+EXPORT_SYMBOL(irq_set_irq_wake);
+
+/*
+ * Internal function that tells the architecture code whether a
+ * particular irq has been exclusively allocated or is available
+ * for driver use.
+ */
+int can_request_irq(unsigned int irq, unsigned long irqflags)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+ int canrequest = 0;
+
+ if (!desc)
+ return 0;
+
+ if (irq_settings_can_request(desc)) {
+ if (!desc->action ||
+ irqflags & desc->action->flags & IRQF_SHARED)
+ canrequest = 1;
+ }
+ irq_put_desc_unlock(desc, flags);
+ return canrequest;
+}
+
+int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
+ unsigned long flags)
+{
+ struct irq_chip *chip = desc->irq_data.chip;
+ int ret, unmask = 0;
+
+ if (!chip || !chip->irq_set_type) {
+ /*
+ * IRQF_TRIGGER_* but the PIC does not support multiple
+ * flow-types?
+ */
+ pr_debug("No set_type function for IRQ %d (%s)\n", irq,
+ chip ? (chip->name ? : "unknown") : "unknown");
+ return 0;
+ }
+
+ flags &= IRQ_TYPE_SENSE_MASK;
+
+ if (chip->flags & IRQCHIP_SET_TYPE_MASKED) {
+ if (!irqd_irq_masked(&desc->irq_data))
+ mask_irq(desc);
+ if (!irqd_irq_disabled(&desc->irq_data))
+ unmask = 1;
+ }
+
+ /* caller masked out all except trigger mode flags */
+ ret = chip->irq_set_type(&desc->irq_data, flags);
+
+ switch (ret) {
+ case IRQ_SET_MASK_OK:
+ case IRQ_SET_MASK_OK_DONE:
+ irqd_clear(&desc->irq_data, IRQD_TRIGGER_MASK);
+ irqd_set(&desc->irq_data, flags);
+
+ case IRQ_SET_MASK_OK_NOCOPY:
+ flags = irqd_get_trigger_type(&desc->irq_data);
+ irq_settings_set_trigger_mask(desc, flags);
+ irqd_clear(&desc->irq_data, IRQD_LEVEL);
+ irq_settings_clr_level(desc);
+ if (flags & IRQ_TYPE_LEVEL_MASK) {
+ irq_settings_set_level(desc);
+ irqd_set(&desc->irq_data, IRQD_LEVEL);
+ }
+
+ ret = 0;
+ break;
+ default:
+ pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
+ flags, irq, chip->irq_set_type);
+ }
+ if (unmask)
+ unmask_irq(desc);
+ return ret;
+}
+
+#ifdef CONFIG_HARDIRQS_SW_RESEND
+int irq_set_parent(int irq, int parent_irq)
+{
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, 0);
+
+ if (!desc)
+ return -EINVAL;
+
+ desc->parent_irq = parent_irq;
+
+ irq_put_desc_unlock(desc, flags);
+ return 0;
+}
+#endif
+
+/*
+ * Default primary interrupt handler for threaded interrupts. Is
+ * assigned as primary handler when request_threaded_irq is called
+ * with handler == NULL. Useful for oneshot interrupts.
+ */
+static irqreturn_t irq_default_primary_handler(int irq, void *dev_id)
+{
+ return IRQ_WAKE_THREAD;
+}
+
+/*
+ * Primary handler for nested threaded interrupts. Should never be
+ * called.
+ */
+static irqreturn_t irq_nested_primary_handler(int irq, void *dev_id)
+{
+ WARN(1, "Primary handler called for nested irq %d\n", irq);
+ return IRQ_NONE;
+}
+
+static int irq_wait_for_interrupt(struct irqaction *action)
+{
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ while (!kthread_should_stop()) {
+
+ if (test_and_clear_bit(IRQTF_RUNTHREAD,
+ &action->thread_flags)) {
+ __set_current_state(TASK_RUNNING);
+ return 0;
+ }
+ schedule();
+ set_current_state(TASK_INTERRUPTIBLE);
+ }
+ __set_current_state(TASK_RUNNING);
+ return -1;
+}
+
+/*
+ * Oneshot interrupts keep the irq line masked until the threaded
+ * handler finished. unmask if the interrupt has not been disabled and
+ * is marked MASKED.
+ */
+static void irq_finalize_oneshot(struct irq_desc *desc,
+ struct irqaction *action)
+{
+ if (!(desc->istate & IRQS_ONESHOT))
+ return;
+again:
+ chip_bus_lock(desc);
+ raw_spin_lock_irq(&desc->lock);
+
+ /*
+ * Implausible though it may be we need to protect us against
+ * the following scenario:
+ *
+ * The thread is faster done than the hard interrupt handler
+ * on the other CPU. If we unmask the irq line then the
+ * interrupt can come in again and masks the line, leaves due
+ * to IRQS_INPROGRESS and the irq line is masked forever.
+ *
+ * This also serializes the state of shared oneshot handlers
+ * versus "desc->threads_onehsot |= action->thread_mask;" in
+ * irq_wake_thread(). See the comment there which explains the
+ * serialization.
+ */
+ if (unlikely(irqd_irq_inprogress(&desc->irq_data))) {
+ raw_spin_unlock_irq(&desc->lock);
+ chip_bus_sync_unlock(desc);
+ cpu_relax();
+ goto again;
+ }
+
+ /*
+ * Now check again, whether the thread should run. Otherwise
+ * we would clear the threads_oneshot bit of this thread which
+ * was just set.
+ */
+ if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+ goto out_unlock;
+
+ desc->threads_oneshot &= ~action->thread_mask;
+
+ if (!desc->threads_oneshot && !irqd_irq_disabled(&desc->irq_data) &&
+ irqd_irq_masked(&desc->irq_data))
+ unmask_threaded_irq(desc);
+
+out_unlock:
+ raw_spin_unlock_irq(&desc->lock);
+ chip_bus_sync_unlock(desc);
+}
+
+#ifdef CONFIG_SMP
+/*
+ * Check whether we need to change the affinity of the interrupt thread.
+ */
+static void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action)
+{
+ cpumask_var_t mask;
+ bool valid = true;
+
+ if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags))
+ return;
+
+ /*
+ * In case we are out of memory we set IRQTF_AFFINITY again and
+ * try again next time
+ */
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+ set_bit(IRQTF_AFFINITY, &action->thread_flags);
+ return;
+ }
+
+ raw_spin_lock_irq(&desc->lock);
+ /*
+ * This code is triggered unconditionally. Check the affinity
+ * mask pointer. For CPU_MASK_OFFSTACK=n this is optimized out.
+ */
+ if (desc->irq_data.affinity)
+ cpumask_copy(mask, desc->irq_data.affinity);
+ else
+ valid = false;
+ raw_spin_unlock_irq(&desc->lock);
+
+ if (valid)
+ set_cpus_allowed_ptr(current, mask);
+ free_cpumask_var(mask);
+}
+#else
+static inline void
+irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) { }
+#endif
+
+/*
+ * Interrupts which are not explicitely requested as threaded
+ * interrupts rely on the implicit bh/preempt disable of the hard irq
+ * context. So we need to disable bh here to avoid deadlocks and other
+ * side effects.
+ */
+static irqreturn_t
+irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action)
+{
+ irqreturn_t ret;
+
+ local_bh_disable();
+ ret = action->thread_fn(action->irq, action->dev_id);
+ irq_finalize_oneshot(desc, action);
+ /*
+ * Interrupts which have real time requirements can be set up
+ * to avoid softirq processing in the thread handler. This is
+ * safe as these interrupts do not raise soft interrupts.
+ */
+ if (irq_settings_no_softirq_call(desc))
+ _local_bh_enable();
+ else
+ local_bh_enable();
+ return ret;
+}
+
+/*
+ * Interrupts explicitly requested as threaded interrupts want to be
+ * preemtible - many of them need to sleep and wait for slow busses to
+ * complete.
+ */
+static irqreturn_t irq_thread_fn(struct irq_desc *desc,
+ struct irqaction *action)
+{
+ irqreturn_t ret;
+
+ ret = action->thread_fn(action->irq, action->dev_id);
+ irq_finalize_oneshot(desc, action);
+ return ret;
+}
+
+static void wake_threads_waitq(struct irq_desc *desc)
+{
+ if (atomic_dec_and_test(&desc->threads_active))
+ wake_up(&desc->wait_for_threads);
+}
+
+static void irq_thread_dtor(struct callback_head *unused)
+{
+ struct task_struct *tsk = current;
+ struct irq_desc *desc;
+ struct irqaction *action;
+
+ if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
+ return;
+
+ action = kthread_data(tsk);
+
+ pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+ tsk->comm, tsk->pid, action->irq);
+
+
+ desc = irq_to_desc(action->irq);
+ /*
+ * If IRQTF_RUNTHREAD is set, we need to decrement
+ * desc->threads_active and wake possible waiters.
+ */
+ if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+ wake_threads_waitq(desc);
+
+ /* Prevent a stale desc->threads_oneshot */
+ irq_finalize_oneshot(desc, action);
+}
+
+/*
+ * Interrupt handler thread
+ */
+static int irq_thread(void *data)
+{
+ struct callback_head on_exit_work;
+ struct irqaction *action = data;
+ struct irq_desc *desc = irq_to_desc(action->irq);
+ irqreturn_t (*handler_fn)(struct irq_desc *desc,
+ struct irqaction *action);
+
+ if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
+ &action->thread_flags))
+ handler_fn = irq_forced_thread_fn;
+ else
+ handler_fn = irq_thread_fn;
+
+ init_task_work(&on_exit_work, irq_thread_dtor);
+ task_work_add(current, &on_exit_work, false);
+
+ irq_thread_check_affinity(desc, action);
+
+ while (!irq_wait_for_interrupt(action)) {
+ irqreturn_t action_ret;
+
+ irq_thread_check_affinity(desc, action);
+
+ action_ret = handler_fn(desc, action);
+ if (action_ret == IRQ_HANDLED)
+ atomic_inc(&desc->threads_handled);
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+ migrate_disable();
+ add_interrupt_randomness(action->irq, 0,
+ desc->random_ip ^ (unsigned long) action);
+ migrate_enable();
+#endif
+ wake_threads_waitq(desc);
+ }
+
+ /*
+ * This is the regular exit path. __free_irq() is stopping the
+ * thread via kthread_stop() after calling
+ * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
+ * oneshot mask bit can be set. We cannot verify that as we
+ * cannot touch the oneshot mask at this point anymore as
+ * __setup_irq() might have given out currents thread_mask
+ * again.
+ */
+ task_work_cancel(current, irq_thread_dtor);
+ return 0;
+}
+
+/**
+ * irq_wake_thread - wake the irq thread for the action identified by dev_id
+ * @irq: Interrupt line
+ * @dev_id: Device identity for which the thread should be woken
+ *
+ */
+void irq_wake_thread(unsigned int irq, void *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct irqaction *action;
+ unsigned long flags;
+
+ if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+ return;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ for (action = desc->action; action; action = action->next) {
+ if (action->dev_id == dev_id) {
+ if (action->thread)
+ __irq_wake_thread(desc, action);
+ break;
+ }
+ }
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+}
+EXPORT_SYMBOL_GPL(irq_wake_thread);
+
+static void irq_setup_forced_threading(struct irqaction *new)
+{
+ if (!force_irqthreads)
+ return;
+ if (new->flags & (IRQF_NO_THREAD | IRQF_PERCPU | IRQF_ONESHOT))
+ return;
+
+ new->flags |= IRQF_ONESHOT;
+
+ if (!new->thread_fn) {
+ set_bit(IRQTF_FORCED_THREAD, &new->thread_flags);
+ new->thread_fn = new->handler;
+ new->handler = irq_default_primary_handler;
+ }
+}
+
+static int irq_request_resources(struct irq_desc *desc)
+{
+ struct irq_data *d = &desc->irq_data;
+ struct irq_chip *c = d->chip;
+
+ return c->irq_request_resources ? c->irq_request_resources(d) : 0;
+}
+
+static void irq_release_resources(struct irq_desc *desc)
+{
+ struct irq_data *d = &desc->irq_data;
+ struct irq_chip *c = d->chip;
+
+ if (c->irq_release_resources)
+ c->irq_release_resources(d);
+}
+
+/*
+ * Internal function to register an irqaction - typically used to
+ * allocate special interrupts that are part of the architecture.
+ */
+static int
+__setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
+{
+ struct irqaction *old, **old_ptr;
+ unsigned long flags, thread_mask = 0;
+ int ret, nested, shared = 0;
+ cpumask_var_t mask;
+
+ if (!desc)
+ return -EINVAL;
+
+ if (desc->irq_data.chip == &no_irq_chip)
+ return -ENOSYS;
+ if (!try_module_get(desc->owner))
+ return -ENODEV;
+
+ /*
+ * Check whether the interrupt nests into another interrupt
+ * thread.
+ */
+ nested = irq_settings_is_nested_thread(desc);
+ if (nested) {
+ if (!new->thread_fn) {
+ ret = -EINVAL;
+ goto out_mput;
+ }
+ /*
+ * Replace the primary handler which was provided from
+ * the driver for non nested interrupt handling by the
+ * dummy function which warns when called.
+ */
+ new->handler = irq_nested_primary_handler;
+ } else {
+ if (irq_settings_can_thread(desc))
+ irq_setup_forced_threading(new);
+ }
+
+ /*
+ * Create a handler thread when a thread function is supplied
+ * and the interrupt does not nest into another interrupt
+ * thread.
+ */
+ if (new->thread_fn && !nested) {
+ struct task_struct *t;
+ static const struct sched_param param = {
+ .sched_priority = MAX_USER_RT_PRIO/2,
+ };
+
+ t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
+ new->name);
+ if (IS_ERR(t)) {
+ ret = PTR_ERR(t);
+ goto out_mput;
+ }
+
+ sched_setscheduler_nocheck(t, SCHED_FIFO, ¶m);
+
+ /*
+ * We keep the reference to the task struct even if
+ * the thread dies to avoid that the interrupt code
+ * references an already freed task_struct.
+ */
+ get_task_struct(t);
+ new->thread = t;
+ /*
+ * Tell the thread to set its affinity. This is
+ * important for shared interrupt handlers as we do
+ * not invoke setup_affinity() for the secondary
+ * handlers as everything is already set up. Even for
+ * interrupts marked with IRQF_NO_BALANCE this is
+ * correct as we want the thread to move to the cpu(s)
+ * on which the requesting code placed the interrupt.
+ */
+ set_bit(IRQTF_AFFINITY, &new->thread_flags);
+ }
+
+ if (!alloc_cpumask_var(&mask, GFP_KERNEL)) {
+ ret = -ENOMEM;
+ goto out_thread;
+ }
+
+ /*
+ * Drivers are often written to work w/o knowledge about the
+ * underlying irq chip implementation, so a request for a
+ * threaded irq without a primary hard irq context handler
+ * requires the ONESHOT flag to be set. Some irq chips like
+ * MSI based interrupts are per se one shot safe. Check the
+ * chip flags, so we can avoid the unmask dance at the end of
+ * the threaded handler for those.
+ */
+ if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
+ new->flags &= ~IRQF_ONESHOT;
+
+ /*
+ * The following block of code has to be executed atomically
+ */
+ raw_spin_lock_irqsave(&desc->lock, flags);
+ old_ptr = &desc->action;
+ old = *old_ptr;
+ if (old) {
+ /*
+ * Can't share interrupts unless both agree to and are
+ * the same type (level, edge, polarity). So both flag
+ * fields must have IRQF_SHARED set and the bits which
+ * set the trigger type must match. Also all must
+ * agree on ONESHOT.
+ */
+ if (!((old->flags & new->flags) & IRQF_SHARED) ||
+ ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
+ ((old->flags ^ new->flags) & IRQF_ONESHOT))
+ goto mismatch;
+
+ /* All handlers must agree on per-cpuness */
+ if ((old->flags & IRQF_PERCPU) !=
+ (new->flags & IRQF_PERCPU))
+ goto mismatch;
+
+ /* add new interrupt at end of irq queue */
+ do {
+ /*
+ * Or all existing action->thread_mask bits,
+ * so we can find the next zero bit for this
+ * new action.
+ */
+ thread_mask |= old->thread_mask;
+ old_ptr = &old->next;
+ old = *old_ptr;
+ } while (old);
+ shared = 1;
+ }
+
+ /*
+ * Setup the thread mask for this irqaction for ONESHOT. For
+ * !ONESHOT irqs the thread mask is 0 so we can avoid a
+ * conditional in irq_wake_thread().
+ */
+ if (new->flags & IRQF_ONESHOT) {
+ /*
+ * Unlikely to have 32 resp 64 irqs sharing one line,
+ * but who knows.
+ */
+ if (thread_mask == ~0UL) {
+ ret = -EBUSY;
+ goto out_mask;
+ }
+ /*
+ * The thread_mask for the action is or'ed to
+ * desc->thread_active to indicate that the
+ * IRQF_ONESHOT thread handler has been woken, but not
+ * yet finished. The bit is cleared when a thread
+ * completes. When all threads of a shared interrupt
+ * line have completed desc->threads_active becomes
+ * zero and the interrupt line is unmasked. See
+ * handle.c:irq_wake_thread() for further information.
+ *
+ * If no thread is woken by primary (hard irq context)
+ * interrupt handlers, then desc->threads_active is
+ * also checked for zero to unmask the irq line in the
+ * affected hard irq flow handlers
+ * (handle_[fasteoi|level]_irq).
+ *
+ * The new action gets the first zero bit of
+ * thread_mask assigned. See the loop above which or's
+ * all existing action->thread_mask bits.
+ */
+ new->thread_mask = 1 << ffz(thread_mask);
+
+ } else if (new->handler == irq_default_primary_handler &&
+ !(desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)) {
+ /*
+ * The interrupt was requested with handler = NULL, so
+ * we use the default primary handler for it. But it
+ * does not have the oneshot flag set. In combination
+ * with level interrupts this is deadly, because the
+ * default primary handler just wakes the thread, then
+ * the irq lines is reenabled, but the device still
+ * has the level irq asserted. Rinse and repeat....
+ *
+ * While this works for edge type interrupts, we play
+ * it safe and reject unconditionally because we can't
+ * say for sure which type this interrupt really
+ * has. The type flags are unreliable as the
+ * underlying chip implementation can override them.
+ */
+ pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
+ irq);
+ ret = -EINVAL;
+ goto out_mask;
+ }
+
+ if (!shared) {
+ ret = irq_request_resources(desc);
+ if (ret) {
+ pr_err("Failed to request resources for %s (irq %d) on irqchip %s\n",
+ new->name, irq, desc->irq_data.chip->name);
+ goto out_mask;
+ }
+
+ init_waitqueue_head(&desc->wait_for_threads);
+
+ /* Setup the type (level, edge polarity) if configured: */
+ if (new->flags & IRQF_TRIGGER_MASK) {
+ ret = __irq_set_trigger(desc, irq,
+ new->flags & IRQF_TRIGGER_MASK);
+
+ if (ret)
+ goto out_mask;
+ }
+
+ desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
+ IRQS_ONESHOT | IRQS_WAITING);
+ irqd_clear(&desc->irq_data, IRQD_IRQ_INPROGRESS);
+
+ if (new->flags & IRQF_PERCPU) {
+ irqd_set(&desc->irq_data, IRQD_PER_CPU);
+ irq_settings_set_per_cpu(desc);
+ }
+
+ if (new->flags & IRQF_ONESHOT)
+ desc->istate |= IRQS_ONESHOT;
+
+ if (irq_settings_can_autoenable(desc))
+ irq_startup(desc, true);
+ else
+ /* Undo nested disables: */
+ desc->depth = 1;
+
+ /* Exclude IRQ from balancing if requested */
+ if (new->flags & IRQF_NOBALANCING) {
+ irq_settings_set_no_balancing(desc);
+ irqd_set(&desc->irq_data, IRQD_NO_BALANCING);
+ }
+
+ if (new->flags & IRQF_NO_SOFTIRQ_CALL)
+ irq_settings_set_no_softirq_call(desc);
+
+ /* Set default affinity mask once everything is setup */
+ setup_affinity(irq, desc, mask);
+
+ } else if (new->flags & IRQF_TRIGGER_MASK) {
+ unsigned int nmsk = new->flags & IRQF_TRIGGER_MASK;
+ unsigned int omsk = irq_settings_get_trigger_mask(desc);
+
+ if (nmsk != omsk)
+ /* hope the handler works with current trigger mode */
+ pr_warning("irq %d uses trigger mode %u; requested %u\n",
+ irq, nmsk, omsk);
+ }
+
+ new->irq = irq;
+ *old_ptr = new;
+
+ irq_pm_install_action(desc, new);
+
+ /* Reset broken irq detection when installing new handler */
+ desc->irq_count = 0;
+ desc->irqs_unhandled = 0;
+
+ /*
+ * Check whether we disabled the irq via the spurious handler
+ * before. Reenable it and give it another chance.
+ */
+ if (shared && (desc->istate & IRQS_SPURIOUS_DISABLED)) {
+ desc->istate &= ~IRQS_SPURIOUS_DISABLED;
+ __enable_irq(desc, irq);
+ }
+
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ /*
+ * Strictly no need to wake it up, but hung_task complains
+ * when no hard interrupt wakes the thread up.
+ */
+ if (new->thread)
+ wake_up_process(new->thread);
+
+ register_irq_proc(irq, desc);
+ new->dir = NULL;
+ register_handler_proc(irq, new);
+ free_cpumask_var(mask);
+
+ return 0;
+
+mismatch:
+ if (!(new->flags & IRQF_PROBE_SHARED)) {
+ pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
+ irq, new->flags, new->name, old->flags, old->name);
+#ifdef CONFIG_DEBUG_SHIRQ
+ dump_stack();
+#endif
+ }
+ ret = -EBUSY;
+
+out_mask:
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+ free_cpumask_var(mask);
+
+out_thread:
+ if (new->thread) {
+ struct task_struct *t = new->thread;
+
+ new->thread = NULL;
+ kthread_stop(t);
+ put_task_struct(t);
+ }
+out_mput:
+ module_put(desc->owner);
+ return ret;
+}
+
+/**
+ * setup_irq - setup an interrupt
+ * @irq: Interrupt line to setup
+ * @act: irqaction for the interrupt
+ *
+ * Used to statically setup interrupts in the early boot process.
+ */
+int setup_irq(unsigned int irq, struct irqaction *act)
+{
+ int retval;
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+ return -EINVAL;
+ chip_bus_lock(desc);
+ retval = __setup_irq(irq, desc, act);
+ chip_bus_sync_unlock(desc);
+
+ return retval;
+}
+EXPORT_SYMBOL_GPL(setup_irq);
+
+/*
+ * Internal function to unregister an irqaction - used to free
+ * regular and special interrupts that are part of the architecture.
+ */
+static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct irqaction *action, **action_ptr;
+ unsigned long flags;
+
+ WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
+
+ if (!desc)
+ return NULL;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+
+ /*
+ * There can be multiple actions per IRQ descriptor, find the right
+ * one based on the dev_id:
+ */
+ action_ptr = &desc->action;
+ for (;;) {
+ action = *action_ptr;
+
+ if (!action) {
+ WARN(1, "Trying to free already-free IRQ %d\n", irq);
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ return NULL;
+ }
+
+ if (action->dev_id == dev_id)
+ break;
+ action_ptr = &action->next;
+ }
+
+ /* Found it - now remove it from the list of entries: */
+ *action_ptr = action->next;
+
+ irq_pm_remove_action(desc, action);
+
+ /* If this was the last handler, shut down the IRQ line: */
+ if (!desc->action) {
+ irq_shutdown(desc);
+ irq_release_resources(desc);
+ }
+
+#ifdef CONFIG_SMP
+ /* make sure affinity_hint is cleaned up */
+ if (WARN_ON_ONCE(desc->affinity_hint))
+ desc->affinity_hint = NULL;
+#endif
+
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ unregister_handler_proc(irq, action);
+
+ /* Make sure it's not being used on another CPU: */
+ synchronize_irq(irq);
+
+#ifdef CONFIG_DEBUG_SHIRQ
+ /*
+ * It's a shared IRQ -- the driver ought to be prepared for an IRQ
+ * event to happen even now it's being freed, so let's make sure that
+ * is so by doing an extra call to the handler ....
+ *
+ * ( We do this after actually deregistering it, to make sure that a
+ * 'real' IRQ doesn't run in * parallel with our fake. )
+ */
+ if (action->flags & IRQF_SHARED) {
+ local_irq_save(flags);
+ action->handler(irq, dev_id);
+ local_irq_restore(flags);
+ }
+#endif
+
+ if (action->thread) {
+ kthread_stop(action->thread);
+ put_task_struct(action->thread);
+ }
+
+ module_put(desc->owner);
+ return action;
+}
+
+/**
+ * remove_irq - free an interrupt
+ * @irq: Interrupt line to free
+ * @act: irqaction for the interrupt
+ *
+ * Used to remove interrupts statically setup by the early boot process.
+ */
+void remove_irq(unsigned int irq, struct irqaction *act)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (desc && !WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+ __free_irq(irq, act->dev_id);
+}
+EXPORT_SYMBOL_GPL(remove_irq);
+
+/**
+ * free_irq - free an interrupt allocated with request_irq
+ * @irq: Interrupt line to free
+ * @dev_id: Device identity to free
+ *
+ * Remove an interrupt handler. The handler is removed and if the
+ * interrupt line is no longer in use by any driver it is disabled.
+ * On a shared IRQ the caller must ensure the interrupt is disabled
+ * on the card it drives before calling this function. The function
+ * does not return until any executing interrupts for this IRQ
+ * have completed.
+ *
+ * This function must not be called from interrupt context.
+ */
+void free_irq(unsigned int irq, void *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (!desc || WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+ return;
+
+#ifdef CONFIG_SMP
+ if (WARN_ON(desc->affinity_notify))
+ desc->affinity_notify = NULL;
+#endif
+
+ chip_bus_lock(desc);
+ kfree(__free_irq(irq, dev_id));
+ chip_bus_sync_unlock(desc);
+}
+EXPORT_SYMBOL(free_irq);
+
+/**
+ * request_threaded_irq - allocate an interrupt line
+ * @irq: Interrupt line to allocate
+ * @handler: Function to be called when the IRQ occurs.
+ * Primary handler for threaded interrupts
+ * If NULL and thread_fn != NULL the default
+ * primary handler is installed
+ * @thread_fn: Function called from the irq handler thread
+ * If NULL, no irq thread is created
+ * @irqflags: Interrupt type flags
+ * @devname: An ascii name for the claiming device
+ * @dev_id: A cookie passed back to the handler function
+ *
+ * This call allocates interrupt resources and enables the
+ * interrupt line and IRQ handling. From the point this
+ * call is made your handler function may be invoked. Since
+ * your handler function must clear any interrupt the board
+ * raises, you must take care both to initialise your hardware
+ * and to set up the interrupt handler in the right order.
+ *
+ * If you want to set up a threaded irq handler for your device
+ * then you need to supply @handler and @thread_fn. @handler is
+ * still called in hard interrupt context and has to check
+ * whether the interrupt originates from the device. If yes it
+ * needs to disable the interrupt on the device and return
+ * IRQ_WAKE_THREAD which will wake up the handler thread and run
+ * @thread_fn. This split handler design is necessary to support
+ * shared interrupts.
+ *
+ * Dev_id must be globally unique. Normally the address of the
+ * device data structure is used as the cookie. Since the handler
+ * receives this value it makes sense to use it.
+ *
+ * If your interrupt is shared you must pass a non NULL dev_id
+ * as this is required when freeing the interrupt.
+ *
+ * Flags:
+ *
+ * IRQF_SHARED Interrupt is shared
+ * IRQF_TRIGGER_* Specify active edge(s) or level
+ *
+ */
+int request_threaded_irq(unsigned int irq, irq_handler_t handler,
+ irq_handler_t thread_fn, unsigned long irqflags,
+ const char *devname, void *dev_id)
+{
+ struct irqaction *action;
+ struct irq_desc *desc;
+ int retval;
+
+ /*
+ * Sanity-check: shared interrupts must pass in a real dev-ID,
+ * otherwise we'll have trouble later trying to figure out
+ * which interrupt is which (messes up the interrupt freeing
+ * logic etc).
+ *
+ * Also IRQF_COND_SUSPEND only makes sense for shared interrupts and
+ * it cannot be set along with IRQF_NO_SUSPEND.
+ */
+ if (((irqflags & IRQF_SHARED) && !dev_id) ||
+ (!(irqflags & IRQF_SHARED) && (irqflags & IRQF_COND_SUSPEND)) ||
+ ((irqflags & IRQF_NO_SUSPEND) && (irqflags & IRQF_COND_SUSPEND)))
+ return -EINVAL;
+
+ desc = irq_to_desc(irq);
+ if (!desc)
+ return -EINVAL;
+
+ if (!irq_settings_can_request(desc) ||
+ WARN_ON(irq_settings_is_per_cpu_devid(desc)))
+ return -EINVAL;
+
+ if (!handler) {
+ if (!thread_fn)
+ return -EINVAL;
+ handler = irq_default_primary_handler;
+ }
+
+ action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+ if (!action)
+ return -ENOMEM;
+
+ action->handler = handler;
+ action->thread_fn = thread_fn;
+ action->flags = irqflags;
+ action->name = devname;
+ action->dev_id = dev_id;
+
+ chip_bus_lock(desc);
+ retval = __setup_irq(irq, desc, action);
+ chip_bus_sync_unlock(desc);
+
+ if (retval)
+ kfree(action);
+
+#ifdef CONFIG_DEBUG_SHIRQ_FIXME
+ if (!retval && (irqflags & IRQF_SHARED)) {
+ /*
+ * It's a shared IRQ -- the driver ought to be prepared for it
+ * to happen immediately, so let's make sure....
+ * We disable the irq to make sure that a 'real' IRQ doesn't
+ * run in parallel with our fake.
+ */
+ unsigned long flags;
+
+ disable_irq(irq);
+ local_irq_save(flags);
+
+ handler(irq, dev_id);
+
+ local_irq_restore(flags);
+ enable_irq(irq);
+ }
+#endif
+ return retval;
+}
+EXPORT_SYMBOL(request_threaded_irq);
+
+/**
+ * request_any_context_irq - allocate an interrupt line
+ * @irq: Interrupt line to allocate
+ * @handler: Function to be called when the IRQ occurs.
+ * Threaded handler for threaded interrupts.
+ * @flags: Interrupt type flags
+ * @name: An ascii name for the claiming device
+ * @dev_id: A cookie passed back to the handler function
+ *
+ * This call allocates interrupt resources and enables the
+ * interrupt line and IRQ handling. It selects either a
+ * hardirq or threaded handling method depending on the
+ * context.
+ *
+ * On failure, it returns a negative value. On success,
+ * it returns either IRQC_IS_HARDIRQ or IRQC_IS_NESTED.
+ */
+int request_any_context_irq(unsigned int irq, irq_handler_t handler,
+ unsigned long flags, const char *name, void *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ int ret;
+
+ if (!desc)
+ return -EINVAL;
+
+ if (irq_settings_is_nested_thread(desc)) {
+ ret = request_threaded_irq(irq, NULL, handler,
+ flags, name, dev_id);
+ return !ret ? IRQC_IS_NESTED : ret;
+ }
+
+ ret = request_irq(irq, handler, flags, name, dev_id);
+ return !ret ? IRQC_IS_HARDIRQ : ret;
+}
+EXPORT_SYMBOL_GPL(request_any_context_irq);
+
+void enable_percpu_irq(unsigned int irq, unsigned int type)
+{
+ unsigned int cpu = smp_processor_id();
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
+
+ if (!desc)
+ return;
+
+ type &= IRQ_TYPE_SENSE_MASK;
+ if (type != IRQ_TYPE_NONE) {
+ int ret;
+
+ ret = __irq_set_trigger(desc, irq, type);
+
+ if (ret) {
+ WARN(1, "failed to set type for IRQ%d\n", irq);
+ goto out;
+ }
+ }
+
+ irq_percpu_enable(desc, cpu);
+out:
+ irq_put_desc_unlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(enable_percpu_irq);
+
+void disable_percpu_irq(unsigned int irq)
+{
+ unsigned int cpu = smp_processor_id();
+ unsigned long flags;
+ struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_PERCPU);
+
+ if (!desc)
+ return;
+
+ irq_percpu_disable(desc, cpu);
+ irq_put_desc_unlock(desc, flags);
+}
+EXPORT_SYMBOL_GPL(disable_percpu_irq);
+
+/*
+ * Internal function to unregister a percpu irqaction.
+ */
+static struct irqaction *__free_percpu_irq(unsigned int irq, void __percpu *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ struct irqaction *action;
+ unsigned long flags;
+
+ WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);
+
+ if (!desc)
+ return NULL;
+
+ raw_spin_lock_irqsave(&desc->lock, flags);
+
+ action = desc->action;
+ if (!action || action->percpu_dev_id != dev_id) {
+ WARN(1, "Trying to free already-free IRQ %d\n", irq);
+ goto bad;
+ }
+
+ if (!cpumask_empty(desc->percpu_enabled)) {
+ WARN(1, "percpu IRQ %d still enabled on CPU%d!\n",
+ irq, cpumask_first(desc->percpu_enabled));
+ goto bad;
+ }
+
+ /* Found it - now remove it from the list of entries: */
+ desc->action = NULL;
+
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+
+ unregister_handler_proc(irq, action);
+
+ module_put(desc->owner);
+ return action;
+
+bad:
+ raw_spin_unlock_irqrestore(&desc->lock, flags);
+ return NULL;
+}
+
+/**
+ * remove_percpu_irq - free a per-cpu interrupt
+ * @irq: Interrupt line to free
+ * @act: irqaction for the interrupt
+ *
+ * Used to remove interrupts statically setup by the early boot process.
+ */
+void remove_percpu_irq(unsigned int irq, struct irqaction *act)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (desc && irq_settings_is_per_cpu_devid(desc))
+ __free_percpu_irq(irq, act->percpu_dev_id);
+}
+
+/**
+ * free_percpu_irq - free an interrupt allocated with request_percpu_irq
+ * @irq: Interrupt line to free
+ * @dev_id: Device identity to free
+ *
+ * Remove a percpu interrupt handler. The handler is removed, but
+ * the interrupt line is not disabled. This must be done on each
+ * CPU before calling this function. The function does not return
+ * until any executing interrupts for this IRQ have completed.
+ *
+ * This function must not be called from interrupt context.
+ */
+void free_percpu_irq(unsigned int irq, void __percpu *dev_id)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+
+ if (!desc || !irq_settings_is_per_cpu_devid(desc))
+ return;
+
+ chip_bus_lock(desc);
+ kfree(__free_percpu_irq(irq, dev_id));
+ chip_bus_sync_unlock(desc);
+}
+
+/**
+ * setup_percpu_irq - setup a per-cpu interrupt
+ * @irq: Interrupt line to setup
+ * @act: irqaction for the interrupt
+ *
+ * Used to statically setup per-cpu interrupts in the early boot process.
+ */
+int setup_percpu_irq(unsigned int irq, struct irqaction *act)
+{
+ struct irq_desc *desc = irq_to_desc(irq);
+ int retval;
+
+ if (!desc || !irq_settings_is_per_cpu_devid(desc))
+ return -EINVAL;
+ chip_bus_lock(desc);
+ retval = __setup_irq(irq, desc, act);
+ chip_bus_sync_unlock(desc);
+
+ return retval;
+}
+
+/**
+ * request_percpu_irq - allocate a percpu interrupt line
+ * @irq: Interrupt line to allocate
+ * @handler: Function to be called when the IRQ occurs.
+ * @devname: An ascii name for the claiming device
+ * @dev_id: A percpu cookie passed back to the handler function
+ *
+ * This call allocates interrupt resources, but doesn't
+ * automatically enable the interrupt. It has to be done on each
+ * CPU using enable_percpu_irq().
+ *
+ * Dev_id must be globally unique. It is a per-cpu variable, and
+ * the handler gets called with the interrupted CPU's instance of
+ * that variable.
+ */
+int request_percpu_irq(unsigned int irq, irq_handler_t handler,
+ const char *devname, void __percpu *dev_id)
+{
+ struct irqaction *action;
+ struct irq_desc *desc;
+ int retval;
+
+ if (!dev_id)
+ return -EINVAL;
+
+ desc = irq_to_desc(irq);
+ if (!desc || !irq_settings_can_request(desc) ||
+ !irq_settings_is_per_cpu_devid(desc))
+ return -EINVAL;
+
+ action = kzalloc(sizeof(struct irqaction), GFP_KERNEL);
+ if (!action)
+ return -ENOMEM;
+
+ action->handler = handler;
+ action->flags = IRQF_PERCPU | IRQF_NO_SUSPEND;
+ action->name = devname;
+ action->percpu_dev_id = dev_id;
+
+ chip_bus_lock(desc);
+ retval = __setup_irq(irq, desc, action);
+ chip_bus_sync_unlock(desc);
+
+ if (retval)
+ kfree(action);
+
+ return retval;
+}
+
+/**
+ * irq_get_irqchip_state - returns the irqchip state of a interrupt.
+ * @irq: Interrupt line that is forwarded to a VM
+ * @which: One of IRQCHIP_STATE_* the caller wants to know about
+ * @state: a pointer to a boolean where the state is to be storeed
+ *
+ * This call snapshots the internal irqchip state of an
+ * interrupt, returning into @state the bit corresponding to
+ * stage @which
+ *
+ * This function should be called with preemption disabled if the
+ * interrupt controller has per-cpu registers.
+ */
+int irq_get_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+ bool *state)
+{
+ struct irq_desc *desc;
+ struct irq_data *data;
+ struct irq_chip *chip;
+ unsigned long flags;
+ int err = -EINVAL;
+
+ desc = irq_get_desc_buslock(irq, &flags, 0);
+ if (!desc)
+ return err;
+
+ data = irq_desc_get_irq_data(desc);
+
+ do {
+ chip = irq_data_get_irq_chip(data);
+ if (chip->irq_get_irqchip_state)
+ break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+ data = data->parent_data;
+#else
+ data = NULL;
+#endif
+ } while (data);
+
+ if (data)
+ err = chip->irq_get_irqchip_state(data, which, state);
+
+ irq_put_desc_busunlock(desc, flags);
+ return err;
+}
+
+/**
+ * irq_set_irqchip_state - set the state of a forwarded interrupt.
+ * @irq: Interrupt line that is forwarded to a VM
+ * @which: State to be restored (one of IRQCHIP_STATE_*)
+ * @val: Value corresponding to @which
+ *
+ * This call sets the internal irqchip state of an interrupt,
+ * depending on the value of @which.
+ *
+ * This function should be called with preemption disabled if the
+ * interrupt controller has per-cpu registers.
+ */
+int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
+ bool val)
+{
+ struct irq_desc *desc;
+ struct irq_data *data;
+ struct irq_chip *chip;
+ unsigned long flags;
+ int err = -EINVAL;
+
+ desc = irq_get_desc_buslock(irq, &flags, 0);
+ if (!desc)
+ return err;
+
+ data = irq_desc_get_irq_data(desc);
+
+ do {
+ chip = irq_data_get_irq_chip(data);
+ if (chip->irq_set_irqchip_state)
+ break;
+#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
+ data = data->parent_data;
+#else
+ data = NULL;
+#endif
+ } while (data);
+
+ if (data)
+ err = chip->irq_set_irqchip_state(data, which, val);
+
+ irq_put_desc_busunlock(desc, flags);
+ return err;
+}
Code Review / kvmfornfv.git / blobdiff