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/*

 * linux/arch/sh/kernel/irq_maskreg.c

 *

 * Copyright (C) 2001 A&D Co., Ltd. <http://www.aandd.co.jp>

 *

 * This file may be copied or modified under the terms of the GNU

 * General Public License.  See linux/COPYING for more information.

 *

 * Interrupt handling for Simple external interrupt mask register

 *

 * This is for the machine which have single 16 bit register

 * for masking external IRQ individually.

 * Each bit of the register is for masking each interrupt.

 */

#include <linux/config.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/irq.h>

#include <asm/system.h>

#include <asm/io.h>

#include <asm/machvec.h>

/* address of external interrupt mask register

 * address must be set prior to use these (maybe in init_XXX_irq())

 * XXX : is it better to use .config than specifying it in code? */

unsigned short *irq_mask_register = 0;

/* forward declaration */

static unsigned int startup_maskreg_irq(unsigned int irq);

static void shutdown_maskreg_irq(unsigned int irq);

static void enable_maskreg_irq(unsigned int irq);

static void disable_maskreg_irq(unsigned int irq);

static void mask_and_ack_maskreg(unsigned int);

static void end_maskreg_irq(unsigned int irq);

/* hw_interrupt_type */

static struct hw_interrupt_type maskreg_irq_type = {

        " Mask Register",

        startup_maskreg_irq,

        shutdown_maskreg_irq,

        enable_maskreg_irq,

        disable_maskreg_irq,

        mask_and_ack_maskreg,

        end_maskreg_irq

};

/* actual implementatin */

static unsigned int startup_maskreg_irq(unsigned int irq)

{

        enable_maskreg_irq(irq);

        return 0; /* never anything pending */

}

static void shutdown_maskreg_irq(unsigned int irq)

{

        disable_maskreg_irq(irq);

}

static void disable_maskreg_irq(unsigned int irq)

{

        if (irq_mask_register) {

                unsigned long flags;

                unsigned short val, mask = 0x01 << irq;

                /* Set "irq"th bit */

                save_and_cli(flags);

                val = ctrl_inw((unsigned long)irq_mask_register);

                val |= mask;

                ctrl_outw(val, (unsigned long)irq_mask_register);

                restore_flags(flags);

        }

}

static void enable_maskreg_irq(unsigned int irq)

{

        if (irq_mask_register) {

                unsigned long flags;

                unsigned short val, mask = ~(0x01 << irq);

                /* Clear "irq"th bit */

                save_and_cli(flags);

                val = ctrl_inw((unsigned long)irq_mask_register);

                val &= mask;

                ctrl_outw(val, (unsigned long)irq_mask_register);

                restore_flags(flags);

        }

}

static void mask_and_ack_maskreg(unsigned int irq)

{

        disable_maskreg_irq(irq);

}

static void end_maskreg_irq(unsigned int irq)

{

        if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))

                enable_maskreg_irq(irq);

}

void make_maskreg_irq(unsigned int irq)

{

        disable_irq_nosync(irq);

        irq_desc[irq].handler = &maskreg_irq_type;

        disable_maskreg_irq(irq);

}