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cia.c

/*
 *  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)
                  m68k_handle_int(mach_irq);
      }
      return IRQ_HANDLED;
}

static void cia_enable_irq(unsigned int 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_disable_irq(unsigned int 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_controller cia_irq_controller = {
      .name       = "cia",
      .lock       = __SPIN_LOCK_UNLOCKED(cia_irq_controller.lock),
      .enable           = cia_enable_irq,
      .disable    = cia_disable_irq,
};

/*
 * 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_enable_irq(unsigned int irq)
{
      switch (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_disable_irq(unsigned int irq)
{
      switch (irq) {
      case IRQ_AUTO_2:
            amiga_custom.intena = IF_PORTS;
            break;
      case IRQ_AUTO_6:
            amiga_custom.intena = IF_EXTER;
            break;
      }
}

static struct irq_controller auto_irq_controller = {
      .name       = "auto",
      .lock       = __SPIN_LOCK_UNLOCKED(auto_irq_controller.lock),
      .enable           = auto_enable_irq,
      .disable    = auto_disable_irq,
};

void __init cia_init_IRQ(struct ciabase *base)
{
      m68k_setup_irq_controller(&cia_irq_controller, 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_controller, base->handler_irq, 1);
      m68k_irq_startup(base->handler_irq);
      request_irq(base->handler_irq, cia_handler, IRQF_SHARED, base->name, base);
}

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