irqdesc.c

Go to the documentation of this file.

/*
 * Copyright (C) 1992, 1998-2006 Linus Torvalds, Ingo Molnar
 * Copyright (C) 2005-2006, Thomas Gleixner, Russell King
 *
 * This file contains the interrupt descriptor management code
 *
 * Detailed information is available in Documentation/DocBook/genericirq
 *
 */
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/radix-tree.h>
#include <linux/bitmap.h>

#include "internals.h"

/*
 * lockdep: we want to handle all irq_desc locks as a single lock-class:
 */
static struct lock_class_key irq_desc_lock_class;

#if defined(CONFIG_SMP)
static void __init init_irq_default_affinity(void)
{
    alloc_cpumask_var(&irq_default_affinity, GFP_NOWAIT);
    cpumask_setall(irq_default_affinity);
}
#else
static void __init init_irq_default_affinity(void)
{
}
#endif

#ifdef CONFIG_SMP
static int alloc_masks(struct irq_desc *desc, gfp_t gfp, int node)
{
    if (!zalloc_cpumask_var_node(&desc->irq_data.affinity, gfp, node))
        return -ENOMEM;

#ifdef CONFIG_GENERIC_PENDING_IRQ
    if (!zalloc_cpumask_var_node(&desc->pending_mask, gfp, node)) {
        free_cpumask_var(desc->irq_data.affinity);
        return -ENOMEM;
    }
#endif
    return 0;
}

static void desc_smp_init(struct irq_desc *desc, int node)
{
    desc->irq_data.node = node;
    cpumask_copy(desc->irq_data.affinity, irq_default_affinity);
#ifdef CONFIG_GENERIC_PENDING_IRQ
    cpumask_clear(desc->pending_mask);
#endif
}

static inline int desc_node(struct irq_desc *desc)
{
    return desc->irq_data.node;
}

#else
static inline int
alloc_masks(struct irq_desc *desc, gfp_t gfp, int node) { return 0; }
static inline void desc_smp_init(struct irq_desc *desc, int node) { }
static inline int desc_node(struct irq_desc *desc) { return 0; }
#endif

static void desc_set_defaults(unsigned int irq, struct irq_desc *desc, int node,
        struct module *owner)
{
    int cpu;

    desc->irq_data.irq = irq;
    desc->irq_data.chip = &no_irq_chip;
    desc->irq_data.chip_data = NULL;
    desc->irq_data.handler_data = NULL;
    desc->irq_data.msi_desc = NULL;
    irq_settings_clr_and_set(desc, ~0, _IRQ_DEFAULT_INIT_FLAGS);
    irqd_set(&desc->irq_data, IRQD_IRQ_DISABLED);
    desc->handle_irq = handle_bad_irq;
    desc->depth = 1;
    desc->irq_count = 0;
    desc->irqs_unhandled = 0;
    desc->name = NULL;
    desc->owner = owner;
    for_each_possible_cpu(cpu)
        *per_cpu_ptr(desc->kstat_irqs, cpu) = 0;
    desc_smp_init(desc, node);
}

int nr_irqs = NR_IRQS;
EXPORT_SYMBOL_GPL(nr_irqs);

static DEFINE_MUTEX(sparse_irq_lock);
static DECLARE_BITMAP(allocated_irqs, IRQ_BITMAP_BITS);

#ifdef CONFIG_SPARSE_IRQ

static RADIX_TREE(irq_desc_tree, GFP_KERNEL);

static void irq_insert_desc(unsigned int irq, struct irq_desc *desc)
{
    radix_tree_insert(&irq_desc_tree, irq, desc);
}

struct irq_desc *irq_to_desc(unsigned int irq)
{
    return radix_tree_lookup(&irq_desc_tree, irq);
}
EXPORT_SYMBOL(irq_to_desc);

static void delete_irq_desc(unsigned int irq)
{
    radix_tree_delete(&irq_desc_tree, irq);
}

#ifdef CONFIG_SMP
static void free_masks(struct irq_desc *desc)
{
#ifdef CONFIG_GENERIC_PENDING_IRQ
    free_cpumask_var(desc->pending_mask);
#endif
    free_cpumask_var(desc->irq_data.affinity);
}
#else
static inline void free_masks(struct irq_desc *desc) { }
#endif

static struct irq_desc *alloc_desc(int irq, int node, struct module *owner)
{
    struct irq_desc *desc;
    gfp_t gfp = GFP_KERNEL;

    desc = kzalloc_node(sizeof(*desc), gfp, node);
    if (!desc)
        return NULL;
    /* allocate based on nr_cpu_ids */
    desc->kstat_irqs = alloc_percpu(unsigned int);
    if (!desc->kstat_irqs)
        goto err_desc;

    if (alloc_masks(desc, gfp, node))
        goto err_kstat;

    raw_spin_lock_init(&desc->lock);
    lockdep_set_class(&desc->lock, &irq_desc_lock_class);

    desc_set_defaults(irq, desc, node, owner);

    return desc;

err_kstat:
    free_percpu(desc->kstat_irqs);
err_desc:
    kfree(desc);
    return NULL;
}

static void free_desc(unsigned int irq)
{
    struct irq_desc *desc = irq_to_desc(irq);

    unregister_irq_proc(irq, desc);

    mutex_lock(&sparse_irq_lock);
    delete_irq_desc(irq);
    mutex_unlock(&sparse_irq_lock);

    free_masks(desc);
    free_percpu(desc->kstat_irqs);
    kfree(desc);
}

static int alloc_descs(unsigned int start, unsigned int cnt, int node,
               struct module *owner)
{
    struct irq_desc *desc;
    int i;

    for (i = 0; i < cnt; i++) {
        desc = alloc_desc(start + i, node, owner);
        if (!desc)
            goto err;
        mutex_lock(&sparse_irq_lock);
        irq_insert_desc(start + i, desc);
        mutex_unlock(&sparse_irq_lock);
    }
    return start;

err:
    for (i--; i >= 0; i--)
        free_desc(start + i);

    mutex_lock(&sparse_irq_lock);
    bitmap_clear(allocated_irqs, start, cnt);
    mutex_unlock(&sparse_irq_lock);
    return -ENOMEM;
}

static int irq_expand_nr_irqs(unsigned int nr)
{
    if (nr > IRQ_BITMAP_BITS)
        return -ENOMEM;
    nr_irqs = nr;
    return 0;
}

int __init early_irq_init(void)
{
    int i, initcnt, node = first_online_node;
    struct irq_desc *desc;

    init_irq_default_affinity();

    /* Let arch update nr_irqs and return the nr of preallocated irqs */
    initcnt = arch_probe_nr_irqs();
    printk(KERN_INFO "NR_IRQS:%d nr_irqs:%d %d\n", NR_IRQS, nr_irqs, initcnt);

    if (WARN_ON(nr_irqs > IRQ_BITMAP_BITS))
        nr_irqs = IRQ_BITMAP_BITS;

    if (WARN_ON(initcnt > IRQ_BITMAP_BITS))
        initcnt = IRQ_BITMAP_BITS;

    if (initcnt > nr_irqs)
        nr_irqs = initcnt;

    for (i = 0; i < initcnt; i++) {
        desc = alloc_desc(i, node, NULL);
        set_bit(i, allocated_irqs);
        irq_insert_desc(i, desc);
    }
    return arch_early_irq_init();
}

#else /* !CONFIG_SPARSE_IRQ */

struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
    [0 ... NR_IRQS-1] = {
        .handle_irq = handle_bad_irq,
        .depth      = 1,
        .lock       = __RAW_SPIN_LOCK_UNLOCKED(irq_desc->lock),
    }
};

int __init early_irq_init(void)
{
    int count, i, node = first_online_node;
    struct irq_desc *desc;

    init_irq_default_affinity();

    printk(KERN_INFO "NR_IRQS:%d\n", NR_IRQS);

    desc = irq_desc;
    count = ARRAY_SIZE(irq_desc);

    for (i = 0; i < count; i++) {
        desc[i].kstat_irqs = alloc_percpu(unsigned int);
        alloc_masks(&desc[i], GFP_KERNEL, node);
        raw_spin_lock_init(&desc[i].lock);
        lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
        desc_set_defaults(i, &desc[i], node, NULL);
    }
    return arch_early_irq_init();
}

struct irq_desc *irq_to_desc(unsigned int irq)
{
    return (irq < NR_IRQS) ? irq_desc + irq : NULL;
}

static void free_desc(unsigned int irq)
{
    dynamic_irq_cleanup(irq);
}

static inline int alloc_descs(unsigned int start, unsigned int cnt, int node,
                  struct module *owner)
{
    u32 i;

    for (i = 0; i < cnt; i++) {
        struct irq_desc *desc = irq_to_desc(start + i);

        desc->owner = owner;
    }
    return start;
}

static int irq_expand_nr_irqs(unsigned int nr)
{
    return -ENOMEM;
}

#endif /* !CONFIG_SPARSE_IRQ */

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

    if (!desc)
        return -EINVAL;
    generic_handle_irq_desc(irq, desc);
    return 0;
}
EXPORT_SYMBOL_GPL(generic_handle_irq);

/* Dynamic interrupt handling */

void irq_free_descs(unsigned int from, unsigned int cnt)
{
    int i;

    if (from >= nr_irqs || (from + cnt) > nr_irqs)
        return;

    for (i = 0; i < cnt; i++)
        free_desc(from + i);

    mutex_lock(&sparse_irq_lock);
    bitmap_clear(allocated_irqs, from, cnt);
    mutex_unlock(&sparse_irq_lock);
}
EXPORT_SYMBOL_GPL(irq_free_descs);

int __ref
__irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
          struct module *owner)
{
    int start, ret;

    if (!cnt)
        return -EINVAL;

    if (irq >= 0) {
        if (from > irq)
            return -EINVAL;
        from = irq;
    }

    mutex_lock(&sparse_irq_lock);

    start = bitmap_find_next_zero_area(allocated_irqs, IRQ_BITMAP_BITS,
                       from, cnt, 0);
    ret = -EEXIST;
    if (irq >=0 && start != irq)
        goto err;

    if (start + cnt > nr_irqs) {
        ret = irq_expand_nr_irqs(start + cnt);
        if (ret)
            goto err;
    }

    bitmap_set(allocated_irqs, start, cnt);
    mutex_unlock(&sparse_irq_lock);
    return alloc_descs(start, cnt, node, owner);

err:
    mutex_unlock(&sparse_irq_lock);
    return ret;
}
EXPORT_SYMBOL_GPL(__irq_alloc_descs);

int irq_reserve_irqs(unsigned int from, unsigned int cnt)
{
    unsigned int start;
    int ret = 0;

    if (!cnt || (from + cnt) > nr_irqs)
        return -EINVAL;

    mutex_lock(&sparse_irq_lock);
    start = bitmap_find_next_zero_area(allocated_irqs, nr_irqs, from, cnt, 0);
    if (start == from)
        bitmap_set(allocated_irqs, start, cnt);
    else
        ret = -EEXIST;
    mutex_unlock(&sparse_irq_lock);
    return ret;
}

unsigned int irq_get_next_irq(unsigned int offset)
{
    return find_next_bit(allocated_irqs, nr_irqs, offset);
}

struct irq_desc *
__irq_get_desc_lock(unsigned int irq, unsigned long *flags, bool bus,
            unsigned int check)
{
    struct irq_desc *desc = irq_to_desc(irq);

    if (desc) {
        if (check & _IRQ_DESC_CHECK) {
            if ((check & _IRQ_DESC_PERCPU) &&
                !irq_settings_is_per_cpu_devid(desc))
                return NULL;

            if (!(check & _IRQ_DESC_PERCPU) &&
                irq_settings_is_per_cpu_devid(desc))
                return NULL;
        }

        if (bus)
            chip_bus_lock(desc);
        raw_spin_lock_irqsave(&desc->lock, *flags);
    }
    return desc;
}

void __irq_put_desc_unlock(struct irq_desc *desc, unsigned long flags, bool bus)
{
    raw_spin_unlock_irqrestore(&desc->lock, flags);
    if (bus)
        chip_bus_sync_unlock(desc);
}

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

    if (!desc)
        return -EINVAL;

    if (desc->percpu_enabled)
        return -EINVAL;

    desc->percpu_enabled = kzalloc(sizeof(*desc->percpu_enabled), GFP_KERNEL);

    if (!desc->percpu_enabled)
        return -ENOMEM;

    irq_set_percpu_devid_flags(irq);
    return 0;
}

void dynamic_irq_cleanup(unsigned int irq)
{
    struct irq_desc *desc = irq_to_desc(irq);
    unsigned long flags;

    raw_spin_lock_irqsave(&desc->lock, flags);
    desc_set_defaults(irq, desc, desc_node(desc), NULL);
    raw_spin_unlock_irqrestore(&desc->lock, flags);
}

unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
{
    struct irq_desc *desc = irq_to_desc(irq);

    return desc && desc->kstat_irqs ?
            *per_cpu_ptr(desc->kstat_irqs, cpu) : 0;
}

unsigned int kstat_irqs(unsigned int irq)
{
    struct irq_desc *desc = irq_to_desc(irq);
    int cpu;
    int sum = 0;

    if (!desc || !desc->kstat_irqs)
        return 0;
    for_each_possible_cpu(cpu)
        sum += *per_cpu_ptr(desc->kstat_irqs, cpu);
    return sum;
}