// SPDX-License-Identifier: GPL-2.0
/*
 * arch/sh/kernel/cpu/irq/imask.c
 *
 * Copyright (C) 1999, 2000  Niibe Yutaka
 *
 * Simple interrupt handling using IMASK of SR register.
 *
 */
/* NOTE: Will not work on level 15 */
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/bitops.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/irq.h>
#include <linux/bitmap.h>
#include <asm/irq.h>

/* Bitmap of IRQ masked */
#define IMASK_PRIORITY  15

static DECLARE_BITMAP(imask_mask, IMASK_PRIORITY);
static int interrupt_priority;

static inline void set_interrupt_registers(int ip)
{
        unsigned long __dummy;

        asm volatile(
#ifdef CONFIG_CPU_HAS_SR_RB
                     "ldc       %2, r6_bank\n\t"
#endif
                     "stc       sr, %0\n\t"
                     "and       #0xf0, %0\n\t"
                     "shlr2     %0\n\t"
                     "cmp/eq    #0x3c, %0\n\t"
                     "bt/s      1f      ! CLI-ed\n\t"
                     " stc      sr, %0\n\t"
                     "and       %1, %0\n\t"
                     "or        %2, %0\n\t"
                     "ldc       %0, sr\n"
                     "1:"
                     : "=&z" (__dummy)
                     : "r" (~0xf0), "r" (ip << 4)
                     : "t");
}

static void mask_imask_irq(struct irq_data *data)
{
        unsigned int irq = data->irq;

        clear_bit(irq, imask_mask);
        if (interrupt_priority < IMASK_PRIORITY - irq)
                interrupt_priority = IMASK_PRIORITY - irq;
        set_interrupt_registers(interrupt_priority);
}

static void unmask_imask_irq(struct irq_data *data)
{
        unsigned int irq = data->irq;

        set_bit(irq, imask_mask);
        interrupt_priority = IMASK_PRIORITY -
                find_first_zero_bit(imask_mask, IMASK_PRIORITY);
        set_interrupt_registers(interrupt_priority);
}

static struct irq_chip imask_irq_chip = {
        .name           = "SR.IMASK",
        .irq_mask       = mask_imask_irq,
        .irq_unmask     = unmask_imask_irq,
        .irq_mask_ack   = mask_imask_irq,
};

void make_imask_irq(unsigned int irq)
{
        irq_set_chip_and_handler_name(irq, &imask_irq_chip, handle_level_irq,
                                      "level");
}