/*
 * linux/kernel/irq/proc.c
 *
 * Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
 *
 * This file contains the /proc/irq/ handling code.
 */

#include <linux/irq.h>
#include <linux/gfp.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/mutex.h>

#include "internals.h"

/*
 * Access rules:
 *
 * procfs protects read/write of /proc/irq/N/ files against a
 * concurrent free of the interrupt descriptor. remove_proc_entry()
 * immediately prevents new read/writes to happen and waits for
 * already running read/write functions to complete.
 *
 * We remove the proc entries first and then delete the interrupt
 * descriptor from the radix tree and free it. So it is guaranteed
 * that irq_to_desc(N) is valid as long as the read/writes are
 * permitted by procfs.
 *
 * The read from /proc/interrupts is a different problem because there
 * is no protection. So the lookup and the access to irqdesc
 * information must be protected by sparse_irq_lock.
 */
static struct proc_dir_entry *root_irq_dir;

#ifdef CONFIG_SMP

static int show_irq_affinity(int type, struct seq_file *m, void *v)
{
        struct irq_desc *desc = irq_to_desc((long)m->private);
        const struct cpumask *mask = desc->irq_common_data.affinity;

#ifdef CONFIG_GENERIC_PENDING_IRQ
        if (irqd_is_setaffinity_pending(&desc->irq_data))
                mask = desc->pending_mask;
#endif
        if (type)
                seq_printf(m, "%*pbl\n", cpumask_pr_args(mask));
        else
                seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
        return 0;
}

static int irq_affinity_hint_proc_show(struct seq_file *m, void *v)
{
        struct irq_desc *desc = irq_to_desc((long)m->private);
        unsigned long flags;
        cpumask_var_t mask;

        if (!zalloc_cpumask_var(&mask, GFP_KERNEL))
                return -ENOMEM;

        raw_spin_lock_irqsave(&desc->lock, flags);
        if (desc->affinity_hint)
                cpumask_copy(mask, desc->affinity_hint);
        raw_spin_unlock_irqrestore(&desc->lock, flags);

        seq_printf(m, "%*pb\n", cpumask_pr_args(mask));
        free_cpumask_var(mask);

        return 0;
}

#ifndef is_affinity_mask_valid
#define is_affinity_mask_valid(val) 1
#endif

int no_irq_affinity;
static int irq_affinity_proc_show(struct seq_file *m, void *v)
{
        return show_irq_affinity(0, m, v);
}

static int irq_affinity_list_proc_show(struct seq_file *m, void *v)
{
        return show_irq_affinity(1, m, v);
}


static ssize_t write_irq_affinity(int type, struct file *file,
                const char __user *buffer, size_t count, loff_t *pos)
{
        unsigned int irq = (int)(long)PDE_DATA(file_inode(file));
        cpumask_var_t new_value;
        int err;

        if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
                return -EIO;

        if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
                return -ENOMEM;

        if (type)
                err = cpumask_parselist_user(buffer, count, new_value);
        else
                err = cpumask_parse_user(buffer, count, new_value);
        if (err)
                goto free_cpumask;

        if (!is_affinity_mask_valid(new_value)) {
                err = -EINVAL;
                goto free_cpumask;
        }

        /*
         * Do not allow disabling IRQs completely - it's a too easy
         * way to make the system unusable accidentally :-) At least
         * one online CPU still has to be targeted.
         */
        if (!cpumask_intersects(new_value, cpu_online_mask)) {
                /* Special case for empty set - allow the architecture
                   code to set default SMP affinity. */
                err = irq_select_affinity_usr(irq, new_value) ? -EINVAL : count;
        } else {
                irq_set_affinity(irq, new_value);
                err = count;
        }

free_cpumask:
        free_cpumask_var(new_value);
        return err;
}

static ssize_t irq_affinity_proc_write(struct file *file,
                const char __user *buffer, size_t count, loff_t *pos)
{
        return write_irq_affinity(0, file, buffer, count, pos);
}

static ssize_t irq_affinity_list_proc_write(struct file *file,
                const char __user *buffer, size_t count, loff_t *pos)
{
        return write_irq_affinity(1, file, buffer, count, pos);
}

static int irq_affinity_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, irq_affinity_proc_show, PDE_DATA(inode));
}

static int irq_affinity_list_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, irq_affinity_list_proc_show, PDE_DATA(inode));
}

static int irq_affinity_hint_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, irq_affinity_hint_proc_show, PDE_DATA(inode));
}

static const struct file_operations irq_affinity_proc_fops = {
        .open           = irq_affinity_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
        .write          = irq_affinity_proc_write,
};

static const struct file_operations irq_affinity_hint_proc_fops = {
        .open           = irq_affinity_hint_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const struct file_operations irq_affinity_list_proc_fops = {
        .open           = irq_affinity_list_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
        .write          = irq_affinity_list_proc_write,
};

static int default_affinity_show(struct seq_file *m, void *v)
{
        seq_printf(m, "%*pb\n", cpumask_pr_args(irq_default_affinity));
        return 0;
}

static ssize_t default_affinity_write(struct file *file,
                const char __user *buffer, size_t count, loff_t *ppos)
{
        cpumask_var_t new_value;
        int err;

        if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
                return -ENOMEM;

        err = cpumask_parse_user(buffer, count, new_value);
        if (err)
                goto out;

        if (!is_affinity_mask_valid(new_value)) {
                err = -EINVAL;
                goto out;
        }

        /*
         * Do not allow disabling IRQs completely - it's a too easy
         * way to make the system unusable accidentally :-) At least
         * one online CPU still has to be targeted.
         */
        if (!cpumask_intersects(new_value, cpu_online_mask)) {
                err = -EINVAL;
                goto out;
        }

        cpumask_copy(irq_default_affinity, new_value);
        err = count;

out:
        free_cpumask_var(new_value);
        return err;
}

static int default_affinity_open(struct inode *inode, struct file *file)
{
        return single_open(file, default_affinity_show, PDE_DATA(inode));
}

static const struct file_operations default_affinity_proc_fops = {
        .open           = default_affinity_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
        .write          = default_affinity_write,
};

static int irq_node_proc_show(struct seq_file *m, void *v)
{
        struct irq_desc *desc = irq_to_desc((long) m->private);

        seq_printf(m, "%d\n", irq_desc_get_node(desc));
        return 0;
}

static int irq_node_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, irq_node_proc_show, PDE_DATA(inode));
}

static const struct file_operations irq_node_proc_fops = {
        .open           = irq_node_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};
#endif

static int irq_spurious_proc_show(struct seq_file *m, void *v)
{
        struct irq_desc *desc = irq_to_desc((long) m->private);

        seq_printf(m, "count %u\n" "unhandled %u\n" "last_unhandled %u ms\n",
                   desc->irq_count, desc->irqs_unhandled,
                   jiffies_to_msecs(desc->last_unhandled));
        return 0;
}

static int irq_spurious_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, irq_spurious_proc_show, PDE_DATA(inode));
}

static const struct file_operations irq_spurious_proc_fops = {
        .open           = irq_spurious_proc_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

#define MAX_NAMELEN 128

static int name_unique(unsigned int irq, struct irqaction *new_action)
{
        struct irq_desc *desc = irq_to_desc(irq);
        struct irqaction *action;
        unsigned long flags;
        int ret = 1;

        raw_spin_lock_irqsave(&desc->lock, flags);
        for_each_action_of_desc(desc, action) {
                if ((action != new_action) && action->name &&
                                !strcmp(new_action->name, action->name)) {
                        ret = 0;
                        break;
                }
        }
        raw_spin_unlock_irqrestore(&desc->lock, flags);
        return ret;
}

void register_handler_proc(unsigned int irq, struct irqaction *action)
{
        char name [MAX_NAMELEN];
        struct irq_desc *desc = irq_to_desc(irq);

        if (!desc->dir || action->dir || !action->name ||
                                        !name_unique(irq, action))
                return;

        snprintf(name, MAX_NAMELEN, "%s", action->name);

        /* create /proc/irq/1234/handler/ */
        action->dir = proc_mkdir(name, desc->dir);
}

#undef MAX_NAMELEN

#define MAX_NAMELEN 10

void register_irq_proc(unsigned int irq, struct irq_desc *desc)
{
        static DEFINE_MUTEX(register_lock);
        char name [MAX_NAMELEN];

        if (!root_irq_dir || (desc->irq_data.chip == &no_irq_chip))
                return;

        /*
         * irq directories are registered only when a handler is
         * added, not when the descriptor is created, so multiple
         * tasks might try to register at the same time.
         */
        mutex_lock(&register_lock);

        if (desc->dir)
                goto out_unlock;

        sprintf(name, "%d", irq);

        /* create /proc/irq/1234 */
        desc->dir = proc_mkdir(name, root_irq_dir);
        if (!desc->dir)
                goto out_unlock;

#ifdef CONFIG_SMP
        /* create /proc/irq/<irq>/smp_affinity */
        proc_create_data("smp_affinity", 0644, desc->dir,
                         &irq_affinity_proc_fops, (void *)(long)irq);

        /* create /proc/irq/<irq>/affinity_hint */
        proc_create_data("affinity_hint", 0444, desc->dir,
                         &irq_affinity_hint_proc_fops, (void *)(long)irq);

        /* create /proc/irq/<irq>/smp_affinity_list */
        proc_create_data("smp_affinity_list", 0644, desc->dir,
                         &irq_affinity_list_proc_fops, (void *)(long)irq);

        proc_create_data("node", 0444, desc->dir,
                         &irq_node_proc_fops, (void *)(long)irq);
#endif

        proc_create_data("spurious", 0444, desc->dir,
                         &irq_spurious_proc_fops, (void *)(long)irq);

out_unlock:
        mutex_unlock(&register_lock);
}

void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
{
        char name [MAX_NAMELEN];

        if (!root_irq_dir || !desc->dir)
                return;
#ifdef CONFIG_SMP
        remove_proc_entry("smp_affinity", desc->dir);
        remove_proc_entry("affinity_hint", desc->dir);
        remove_proc_entry("smp_affinity_list", desc->dir);
        remove_proc_entry("node", desc->dir);
#endif
        remove_proc_entry("spurious", desc->dir);

        sprintf(name, "%u", irq);
        remove_proc_entry(name, root_irq_dir);
}

#undef MAX_NAMELEN

void unregister_handler_proc(unsigned int irq, struct irqaction *action)
{
        proc_remove(action->dir);
}

static void register_default_affinity_proc(void)
{
#ifdef CONFIG_SMP
        proc_create("irq/default_smp_affinity", 0644, NULL,
                    &default_affinity_proc_fops);
#endif
}

void init_irq_proc(void)
{
        unsigned int irq;
        struct irq_desc *desc;

        /* create /proc/irq */
        root_irq_dir = proc_mkdir("irq", NULL);
        if (!root_irq_dir)
                return;

        register_default_affinity_proc();

        /*
         * Create entries for all existing IRQs.
         */
        for_each_irq_desc(irq, desc)
                register_irq_proc(irq, desc);
}

#ifdef CONFIG_GENERIC_IRQ_SHOW

int __weak arch_show_interrupts(struct seq_file *p, int prec)
{
        return 0;
}

#ifndef ACTUAL_NR_IRQS
# define ACTUAL_NR_IRQS nr_irqs
#endif

int show_interrupts(struct seq_file *p, void *v)
{
        static int prec;

        unsigned long flags, any_count = 0;
        int i = *(loff_t *) v, j;
        struct irqaction *action;
        struct irq_desc *desc;

        if (i > ACTUAL_NR_IRQS)
                return 0;

        if (i == ACTUAL_NR_IRQS)
                return arch_show_interrupts(p, prec);

        /* print header and calculate the width of the first column */
        if (i == 0) {
                for (prec = 3, j = 1000; prec < 10 && j <= nr_irqs; ++prec)
                        j *= 10;

                seq_printf(p, "%*s", prec + 8, "");
                for_each_online_cpu(j)
                        seq_printf(p, "CPU%-8d", j);
                seq_putc(p, '\n');
        }

        irq_lock_sparse();
        desc = irq_to_desc(i);
        if (!desc)
                goto outsparse;

        raw_spin_lock_irqsave(&desc->lock, flags);
        for_each_online_cpu(j)
                any_count |= kstat_irqs_cpu(i, j);
        action = desc->action;
        if ((!action || irq_desc_is_chained(desc)) && !any_count)
                goto out;

        seq_printf(p, "%*d: ", prec, i);
        for_each_online_cpu(j)
                seq_printf(p, "%10u ", kstat_irqs_cpu(i, j));

        if (desc->irq_data.chip) {
                if (desc->irq_data.chip->irq_print_chip)
                        desc->irq_data.chip->irq_print_chip(&desc->irq_data, p);
                else if (desc->irq_data.chip->name)
                        seq_printf(p, " %8s", desc->irq_data.chip->name);
                else
                        seq_printf(p, " %8s", "-");
        } else {
                seq_printf(p, " %8s", "None");
        }
        if (desc->irq_data.domain)
                seq_printf(p, " %*d", prec, (int) desc->irq_data.hwirq);
#ifdef CONFIG_GENERIC_IRQ_SHOW_LEVEL
        seq_printf(p, " %-8s", irqd_is_level_type(&desc->irq_data) ? "Level" : "Edge");
#endif
        if (desc->name)
                seq_printf(p, "-%-8s", desc->name);

        if (action) {
                seq_printf(p, "  %s", action->name);
                while ((action = action->next) != NULL)
                        seq_printf(p, ", %s", action->name);
        }

        seq_putc(p, '\n');
out:
        raw_spin_unlock_irqrestore(&desc->lock, flags);
outsparse:
        irq_unlock_sparse();
        return 0;
}
#endif