// SPDX-License-Identifier: GPL-2.0
/*
 *      linux/arch/alpha/kernel/irq.c
 *
 *      Copyright (C) 1995 Linus Torvalds
 *
 * This file contains the code used by various IRQ handling routines:
 * asking for different IRQ's should be done through these routines
 * instead of just grabbing them. Thus setups with different IRQ numbers
 * shouldn't result in any weird surprises, and installing new handlers
 * should be easier.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/interrupt.h>
#include <linux/random.h>
#include <linux/irq.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/profile.h>
#include <linux/bitops.h>

#include <asm/io.h>
#include <linux/uaccess.h>
#include "irq_impl.h"

volatile unsigned long irq_err_count;
DEFINE_PER_CPU(unsigned long, irq_pmi_count);

void ack_bad_irq(unsigned int irq)
{
        irq_err_count++;
        printk(KERN_CRIT "Unexpected IRQ trap at vector %u\n", irq);
}

#ifdef CONFIG_SMP 
static char irq_user_affinity[NR_IRQS];

int irq_select_affinity(unsigned int irq)
{
        struct irq_data *data = irq_get_irq_data(irq);
        struct irq_chip *chip;
        static int last_cpu;
        int cpu = last_cpu + 1;

        if (!data)
                return 1;
        chip = irq_data_get_irq_chip(data);

        if (!chip->irq_set_affinity || irq_user_affinity[irq])
                return 1;

        while (!cpu_possible(cpu) ||
               !cpumask_test_cpu(cpu, irq_default_affinity))
                cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
        last_cpu = cpu;

        irq_data_update_affinity(data, cpumask_of(cpu));
        chip->irq_set_affinity(data, cpumask_of(cpu), false);
        return 0;
}
#endif /* CONFIG_SMP */

int arch_show_interrupts(struct seq_file *p, int prec)
{
        int j;

#ifdef CONFIG_SMP
        seq_puts(p, "IPI: ");
        for_each_online_cpu(j)
                seq_printf(p, "%10lu ", cpu_data[j].ipi_count);
        seq_putc(p, '\n');
#endif
        seq_puts(p, "PMI: ");
        for_each_online_cpu(j)
                seq_printf(p, "%10lu ", per_cpu(irq_pmi_count, j));
        seq_puts(p, "          Performance Monitoring\n");
        seq_printf(p, "ERR: %10lu\n", irq_err_count);
        return 0;
}

/*
 * handle_irq handles all normal device IRQ's (the special
 * SMP cross-CPU interrupts have their own specific
 * handlers).
 */

#define MAX_ILLEGAL_IRQS 16

void
handle_irq(int irq)
{       
        /* 
         * We ack quickly, we don't want the irq controller
         * thinking we're snobs just because some other CPU has
         * disabled global interrupts (we have already done the
         * INT_ACK cycles, it's too late to try to pretend to the
         * controller that we aren't taking the interrupt).
         *
         * 0 return value means that this irq is already being
         * handled by some other CPU. (or is disabled)
         */
        static unsigned int illegal_count=0;
        struct irq_desc *desc = irq_to_desc(irq);
        
        if (!desc || ((unsigned) irq > ACTUAL_NR_IRQS &&
            illegal_count < MAX_ILLEGAL_IRQS)) {
                irq_err_count++;
                illegal_count++;
                printk(KERN_CRIT "device_interrupt: invalid interrupt %d\n",
                       irq);
                return;
        }

        irq_enter();
        generic_handle_irq_desc(desc);
        irq_exit();
}