/*
 * 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 <linux/irqdomain.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

void irq_lock_sparse(void)
{
        mutex_lock(&sparse_irq_lock);
}

void irq_unlock_sparse(void)
{
        mutex_unlock(&sparse_irq_lock);
}

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);

        /*
         * sparse_irq_lock protects also show_interrupts() and
         * kstat_irq_usr(). Once we deleted the descriptor from the
         * sparse tree we can free it. Access in proc will fail to
         * lookup the descriptor.
         */
        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;
}
EXPORT_SYMBOL(irq_to_desc);

static void free_desc(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);
}

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;
}

void irq_mark_irq(unsigned int irq)
{
        mutex_lock(&sparse_irq_lock);
        bitmap_set(allocated_irqs, irq, 1);
        mutex_unlock(&sparse_irq_lock);
}

#ifdef CONFIG_GENERIC_IRQ_LEGACY
void irq_init_desc(unsigned int irq)
{
        free_desc(irq);
}
#endif

#endif /* !CONFIG_SPARSE_IRQ */

/**
 * generic_handle_irq - Invoke the handler for a particular irq
 * @irq:        The irq number to handle
 *
 */
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);

#ifdef CONFIG_HANDLE_DOMAIN_IRQ
/**
 * __handle_domain_irq - Invoke the handler for a HW irq belonging to a domain
 * @domain:     The domain where to perform the lookup
 * @hwirq:      The HW irq number to convert to a logical one
 * @lookup:     Whether to perform the domain lookup or not
 * @regs:       Register file coming from the low-level handling code
 *
 * Returns:     0 on success, or -EINVAL if conversion has failed
 */
int __handle_domain_irq(struct irq_domain *domain, unsigned int hwirq,
                        bool lookup, struct pt_regs *regs)
{
        struct pt_regs *old_regs = set_irq_regs(regs);
        unsigned int irq = hwirq;
        int ret = 0;

        irq_enter();

#ifdef CONFIG_IRQ_DOMAIN
        if (lookup)
                irq = irq_find_mapping(domain, hwirq);
#endif

        /*
         * Some hardware gives randomly wrong interrupts.  Rather
         * than crashing, do something sensible.
         */
        if (unlikely(!irq || irq >= nr_irqs)) {
                ack_bad_irq(irq);
                ret = -EINVAL;
        } else {
                generic_handle_irq(irq);
        }

        irq_exit();
        set_irq_regs(old_regs);
        return ret;
}
#endif

/* Dynamic interrupt handling */

/**
 * irq_free_descs - free irq descriptors
 * @from:       Start of descriptor range
 * @cnt:        Number of consecutive irqs to free
 */
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);

/**
 * irq_alloc_descs - allocate and initialize a range of irq descriptors
 * @irq:        Allocate for specific irq number if irq >= 0
 * @from:       Start the search from this irq number
 * @cnt:        Number of consecutive irqs to allocate.
 * @node:       Preferred node on which the irq descriptor should be allocated
 * @owner:      Owning module (can be NULL)
 *
 * Returns the first irq number or error code
 */
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;
        } else {
                /*
                 * For interrupts which are freely allocated the
                 * architecture can force a lower bound to the @from
                 * argument. x86 uses this to exclude the GSI space.
                 */
                from = arch_dynirq_lower_bound(from);
        }

        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);

#ifdef CONFIG_GENERIC_IRQ_LEGACY_ALLOC_HWIRQ
/**
 * irq_alloc_hwirqs - Allocate an irq descriptor and initialize the hardware
 * @cnt:        number of interrupts to allocate
 * @node:       node on which to allocate
 *
 * Returns an interrupt number > 0 or 0, if the allocation fails.
 */
unsigned int irq_alloc_hwirqs(int cnt, int node)
{
        int i, irq = __irq_alloc_descs(-1, 0, cnt, node, NULL);

        if (irq < 0)
                return 0;

        for (i = irq; cnt > 0; i++, cnt--) {
                if (arch_setup_hwirq(i, node))
                        goto err;
                irq_clear_status_flags(i, _IRQ_NOREQUEST);
        }
        return irq;

err:
        for (i--; i >= irq; i--) {
                irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
                arch_teardown_hwirq(i);
        }
        irq_free_descs(irq, cnt);
        return 0;
}
EXPORT_SYMBOL_GPL(irq_alloc_hwirqs);

/**
 * irq_free_hwirqs - Free irq descriptor and cleanup the hardware
 * @from:       Free from irq number
 * @cnt:        number of interrupts to free
 *
 */
void irq_free_hwirqs(unsigned int from, int cnt)
{
        int i, j;

        for (i = from, j = cnt; j > 0; i++, j--) {
                irq_set_status_flags(i, _IRQ_NOREQUEST | _IRQ_NOPROBE);
                arch_teardown_hwirq(i);
        }
        irq_free_descs(from, cnt);
}
EXPORT_SYMBOL_GPL(irq_free_hwirqs);
#endif

/**
 * irq_get_next_irq - get next allocated irq number
 * @offset:     where to start the search
 *
 * Returns next irq number after offset or nr_irqs if none is found.
 */
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 kstat_incr_irq_this_cpu(unsigned int irq)
{
        kstat_incr_irqs_this_cpu(irq, irq_to_desc(irq));
}

/**
 * kstat_irqs_cpu - Get the statistics for an interrupt on a cpu
 * @irq:        The interrupt number
 * @cpu:        The cpu number
 *
 * Returns the sum of interrupt counts on @cpu since boot for
 * @irq. The caller must ensure that the interrupt is not removed
 * concurrently.
 */
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;
}

/**
 * kstat_irqs - Get the statistics for an interrupt
 * @irq:        The interrupt number
 *
 * Returns the sum of interrupt counts on all cpus since boot for
 * @irq. The caller must ensure that the interrupt is not removed
 * concurrently.
 */
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;
}

/**
 * kstat_irqs_usr - Get the statistics for an interrupt
 * @irq:        The interrupt number
 *
 * Returns the sum of interrupt counts on all cpus since boot for
 * @irq. Contrary to kstat_irqs() this can be called from any
 * preemptible context. It's protected against concurrent removal of
 * an interrupt descriptor when sparse irqs are enabled.
 */
unsigned int kstat_irqs_usr(unsigned int irq)
{
        int sum;

        irq_lock_sparse();
        sum = kstat_irqs(irq);
        irq_unlock_sparse();
        return sum;
}