cia.c

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/*
 *  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 <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;

    mach_irq = base->cia_irq;
    ints = cia_set_irq(base, CIA_ICR_ALL);
    amiga_custom.intreq = base->int_mask;
    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);
}