/*
 *  linux/arch/m68k/amiga/cia.c - CIA support
 *
 *  Copyright (C) 1996 Roman Zippel
 *
 *  The concept of some functions bases on the original Amiga OS function
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/kernel_stat.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/irq.h>

#include <asm/irq.h>
#include <asm/amigahw.h>
#include <asm/amigaints.h>

struct ciabase {
        volatile struct CIA *cia;
        unsigned char icr_mask, icr_data;
        unsigned short int_mask;
        int handler_irq, cia_irq, server_irq;
        char *name;
} ciaa_base = {
        .cia            = &ciaa,
        .int_mask       = IF_PORTS,
        .handler_irq    = IRQ_AMIGA_PORTS,
        .cia_irq        = IRQ_AMIGA_CIAA,
        .name           = "CIAA"
}, ciab_base = {
        .cia            = &ciab,
        .int_mask       = IF_EXTER,
        .handler_irq    = IRQ_AMIGA_EXTER,
        .cia_irq        = IRQ_AMIGA_CIAB,
        .name           = "CIAB"
};

/*
 *  Cause or clear CIA interrupts, return old interrupt status.
 */

unsigned char cia_set_irq(struct ciabase *base, unsigned char mask)
{
        unsigned char old;

        old = (base->icr_data |= base->cia->icr);
        if (mask & CIA_ICR_SETCLR)
                base->icr_data |= mask;
        else
                base->icr_data &= ~mask;
        if (base->icr_data & base->icr_mask)
                amiga_custom.intreq = IF_SETCLR | base->int_mask;
        return old & base->icr_mask;
}

/*
 *  Enable or disable CIA interrupts, return old interrupt mask,
 */

unsigned char cia_able_irq(struct ciabase *base, unsigned char mask)
{
        unsigned char old;

        old = base->icr_mask;
        base->icr_data |= base->cia->icr;
        base->cia->icr = mask;
        if (mask & CIA_ICR_SETCLR)
                base->icr_mask |= mask;
        else
                base->icr_mask &= ~mask;
        base->icr_mask &= CIA_ICR_ALL;
        if (base->icr_data & base->icr_mask)
                amiga_custom.intreq = IF_SETCLR | base->int_mask;
        return old;
}

static irqreturn_t cia_handler(int irq, void *dev_id)
{
        struct ciabase *base = dev_id;
        int mach_irq;
        unsigned char ints;
        unsigned long flags;

        /* Interrupts get disabled while the timer irq flag is cleared and
         * the timer interrupt serviced.
         */
        mach_irq = base->cia_irq;
        local_irq_save(flags);
        ints = cia_set_irq(base, CIA_ICR_ALL);
        amiga_custom.intreq = base->int_mask;
        if (ints & 1)
                generic_handle_irq(mach_irq);
        local_irq_restore(flags);
        mach_irq++, ints >>= 1;
        for (; ints; mach_irq++, ints >>= 1) {
                if (ints & 1)
                        generic_handle_irq(mach_irq);
        }
        return IRQ_HANDLED;
}

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

        if (irq >= IRQ_AMIGA_CIAB) {
                mask = 1 << (irq - IRQ_AMIGA_CIAB);
                cia_set_irq(&ciab_base, mask);
                cia_able_irq(&ciab_base, CIA_ICR_SETCLR | mask);
        } else {
                mask = 1 << (irq - IRQ_AMIGA_CIAA);
                cia_set_irq(&ciaa_base, mask);
                cia_able_irq(&ciaa_base, CIA_ICR_SETCLR | mask);
        }
}

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

        if (irq >= IRQ_AMIGA_CIAB)
                cia_able_irq(&ciab_base, 1 << (irq - IRQ_AMIGA_CIAB));
        else
                cia_able_irq(&ciaa_base, 1 << (irq - IRQ_AMIGA_CIAA));
}

static struct irq_chip cia_irq_chip = {
        .name           = "cia",
        .irq_enable     = cia_irq_enable,
        .irq_disable    = cia_irq_disable,
};

/*
 * Override auto irq 2 & 6 and use them as general chain
 * for external interrupts, we link the CIA interrupt sources
 * into this chain.
 */

static void auto_irq_enable(struct irq_data *data)
{
        switch (data->irq) {
        case IRQ_AUTO_2:
                amiga_custom.intena = IF_SETCLR | IF_PORTS;
                break;
        case IRQ_AUTO_6:
                amiga_custom.intena = IF_SETCLR | IF_EXTER;
                break;
        }
}

static void auto_irq_disable(struct irq_data *data)
{
        switch (data->irq) {
        case IRQ_AUTO_2:
                amiga_custom.intena = IF_PORTS;
                break;
        case IRQ_AUTO_6:
                amiga_custom.intena = IF_EXTER;
                break;
        }
}

static struct irq_chip auto_irq_chip = {
        .name           = "auto",
        .irq_enable     = auto_irq_enable,
        .irq_disable    = auto_irq_disable,
};

void __init cia_init_IRQ(struct ciabase *base)
{
        m68k_setup_irq_controller(&cia_irq_chip, handle_simple_irq,
                                  base->cia_irq, CIA_IRQS);

        /* clear any pending interrupt and turn off all interrupts */
        cia_set_irq(base, CIA_ICR_ALL);
        cia_able_irq(base, CIA_ICR_ALL);

        /* override auto int and install CIA handler */
        m68k_setup_irq_controller(&auto_irq_chip, handle_simple_irq,
                                  base->handler_irq, 1);
        m68k_irq_startup_irq(base->handler_irq);
        if (request_irq(base->handler_irq, cia_handler, IRQF_SHARED,
                        base->name, base))
                pr_err("Couldn't register %s interrupt\n", base->name);
}