/*
   * arch/m68k/q40/q40ints.c
   *
   * Copyright (C) 1999,2001 Richard Zidlicky
   *
   * 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.
   *
   * .. used to be loosely based on bvme6000ints.c
   *
   */
  
  #include <linux/types.h>
  #include <linux/kernel.h>
  #include <linux/errno.h>

  #include <linux/interrupt.h>

  #include <linux/irq.h>

  #include <asm/ptrace.h>
  #include <asm/system.h>

  #include <asm/traps.h>
  
  #include <asm/q40_master.h>
  #include <asm/q40ints.h>
  
  /*
   * Q40 IRQs are defined as follows:
   *            3,4,5,6,7,10,11,14,15 : ISA dev IRQs
   *            16-31: reserved
   *            32   : keyboard int
   *            33   : frame int (50/200 Hz periodic timer)
   *            34   : sample int (10/20 KHz periodic timer)
   *
  */

  static void q40_irq_handler(unsigned int, struct pt_regs *fp);

  static void q40_irq_enable(struct irq_data *data);
  static void q40_irq_disable(struct irq_data *data);

  unsigned short q40_ablecount[35];
  unsigned short q40_state[35];

  static unsigned int q40_irq_startup(struct irq_data *data)

  {

  	unsigned int irq = data->irq;

  	/* test for ISA ints not implemented by HW */
  	switch (irq) {
  	case 1: case 2: case 8: case 9:
  	case 11: case 12: case 13:

  		printk("%s: ISA IRQ %d not implemented by HW
  ", __func__, irq);

  		/* FIXME return -ENXIO; */

  	}
  	return 0;
  }

  static void q40_irq_shutdown(struct irq_data *data)

  {
  }

  static struct irq_chip q40_irq_chip = {

  	.name		= "q40",

  	.irq_startup	= q40_irq_startup,
  	.irq_shutdown	= q40_irq_shutdown,

  	.irq_enable	= q40_irq_enable,
  	.irq_disable	= q40_irq_disable,

  };

  
  /*
   * void q40_init_IRQ (void)
   *
   * Parameters:	None
   *
   * Returns:	Nothing
   *
   * This function is called during kernel startup to initialize
   * the q40 IRQ handling routines.
   */

  static int disabled;

  void __init q40_init_IRQ(void)

  {

  	m68k_setup_irq_controller(&q40_irq_chip, handle_simple_irq, 1,
  				  Q40_IRQ_MAX);

  
  	/* setup handler for ISA ints */

  	m68k_setup_auto_interrupt(q40_irq_handler);

  	m68k_irq_startup_irq(IRQ_AUTO_2);
  	m68k_irq_startup_irq(IRQ_AUTO_4);

  
  	/* now enable some ints.. */

  	master_outb(1, EXT_ENABLE_REG);  /* ISA IRQ 5-15 */

  
  	/* make sure keyboard IRQ is disabled */

  	master_outb(0, KEY_IRQ_ENABLE_REG);

  }

  
  /*
   * this stuff doesn't really belong here..

   */

  
  int ql_ticks;              /* 200Hz ticks since last jiffie */
  static int sound_ticks;
  
  #define SVOL 45
  
  void q40_mksound(unsigned int hz, unsigned int ticks)
  {

  	/* for now ignore hz, except that hz==0 switches off sound */
  	/* simply alternate the ampl (128-SVOL)-(128+SVOL)-..-.. at 200Hz */
  	if (hz == 0) {
  		if (sound_ticks)
  			sound_ticks = 1;
  
  		*DAC_LEFT = 128;
  		*DAC_RIGHT = 128;
  
  		return;
  	}
  	/* sound itself is done in q40_timer_int */
  	if (sound_ticks == 0)
  		sound_ticks = 1000; /* pretty long beep */
  	sound_ticks = ticks << 1;

  }

  static irq_handler_t q40_timer_routine;

  static irqreturn_t q40_timer_int (int irq, void * dev)

  {

  	ql_ticks = ql_ticks ? 0 : 1;
  	if (sound_ticks) {
  		unsigned char sval=(sound_ticks & 1) ? 128-SVOL : 128+SVOL;
  		sound_ticks--;
  		*DAC_LEFT=sval;
  		*DAC_RIGHT=sval;
  	}
  
  	if (!ql_ticks)

  		q40_timer_routine(irq, dev);

  	return IRQ_HANDLED;

  }

  void q40_sched_init (irq_handler_t timer_routine)

  {

  	int timer_irq;

  	q40_timer_routine = timer_routine;
  	timer_irq = Q40_IRQ_FRAME;

  	if (request_irq(timer_irq, q40_timer_int, 0,

  				"timer", q40_timer_int))

  		panic("Couldn't register timer int");

  	master_outb(-1, FRAME_CLEAR_REG);
  	master_outb( 1, FRAME_RATE_REG);

  }
  
  
  /*
   * tables to translate bits into IRQ numbers
   * it is a good idea to order the entries by priority
   *
  */
  
  struct IRQ_TABLE{ unsigned mask; int irq ;};
  #if 0
  static struct IRQ_TABLE iirqs[]={
    {Q40_IRQ_FRAME_MASK,Q40_IRQ_FRAME},
    {Q40_IRQ_KEYB_MASK,Q40_IRQ_KEYBOARD},
    {0,0}};
  #endif
  static struct IRQ_TABLE eirqs[] = {
    { .mask = Q40_IRQ3_MASK,	.irq = 3 },	/* ser 1 */
    { .mask = Q40_IRQ4_MASK,	.irq = 4 },	/* ser 2 */
    { .mask = Q40_IRQ14_MASK,	.irq = 14 },	/* IDE 1 */
    { .mask = Q40_IRQ15_MASK,	.irq = 15 },	/* IDE 2 */
    { .mask = Q40_IRQ6_MASK,	.irq = 6 },	/* floppy, handled elsewhere */
    { .mask = Q40_IRQ7_MASK,	.irq = 7 },	/* par */
    { .mask = Q40_IRQ5_MASK,	.irq = 5 },
    { .mask = Q40_IRQ10_MASK,	.irq = 10 },
    {0,0}
  };
  
  /* complain only this many times about spurious ints : */

  static int ccleirq=60;    /* ISA dev IRQs*/

  /*static int cclirq=60;*/     /* internal */
  
  /* FIXME: add shared ints,mask,unmask,probing.... */
  
  #define IRQ_INPROGRESS 1
  /*static unsigned short saved_mask;*/
  //static int do_tint=0;
  
  #define DEBUG_Q40INT
  /*#define IP_USE_DISABLE *//* would be nice, but crashes ???? */
  
  static int mext_disabled=0;  /* ext irq disabled by master chip? */
  static int aliased_irq=0;  /* how many times inside handler ?*/

  /* got interrupt, dispatch to ISA or keyboard/timer IRQs */
  static void q40_irq_handler(unsigned int irq, struct pt_regs *fp)

  {

  	unsigned mir, mer;
  	int i;

  
  //repeat:

  	mir = master_inb(IIRQ_REG);
  #ifdef CONFIG_BLK_DEV_FD
  	if ((mir & Q40_IRQ_EXT_MASK) &&
  	    (master_inb(EIRQ_REG) & Q40_IRQ6_MASK)) {
  		floppy_hardint();
  		return;
  	}
  #endif
  	switch (irq) {
  	case 4:
  	case 6:

  		do_IRQ(Q40_IRQ_SAMPLE, fp);

  		return;
  	}
  	if (mir & Q40_IRQ_FRAME_MASK) {

  		do_IRQ(Q40_IRQ_FRAME, fp);

  		master_outb(-1, FRAME_CLEAR_REG);
  	}
  	if ((mir & Q40_IRQ_SER_MASK) || (mir & Q40_IRQ_EXT_MASK)) {
  		mer = master_inb(EIRQ_REG);
  		for (i = 0; eirqs[i].mask; i++) {
  			if (mer & eirqs[i].mask) {
  				irq = eirqs[i].irq;

  /*
   * There is a little mess wrt which IRQ really caused this irq request. The
   * main problem is that IIRQ_REG and EIRQ_REG reflect the state when they
   * are read - which is long after the request came in. In theory IRQs should

   * not just go away but they occasionally do

   */

  				if (irq > 4 && irq <= 15 && mext_disabled) {
  					/*aliased_irq++;*/
  					goto iirq;
  				}
  				if (q40_state[irq] & IRQ_INPROGRESS) {
  					/* some handlers do local_irq_enable() for irq latency reasons, */
  					/* however reentering an active irq handler is not permitted */

  #ifdef IP_USE_DISABLE

  					/* in theory this is the better way to do it because it still */
  					/* lets through eg the serial irqs, unfortunately it crashes */
  					disable_irq(irq);
  					disabled = 1;

  #else

  					/*printk("IRQ_INPROGRESS detected for irq %d, disabling - %s disabled
  ",
  						irq, disabled ? "already" : "not yet"); */
  					fp->sr = (((fp->sr) & (~0x700))+0x200);
  					disabled = 1;

  #endif

  					goto iirq;
  				}
  				q40_state[irq] |= IRQ_INPROGRESS;

  				do_IRQ(irq, fp);

  				q40_state[irq] &= ~IRQ_INPROGRESS;
  
  				/* naively enable everything, if that fails than    */
  				/* this function will be reentered immediately thus */
  				/* getting another chance to disable the IRQ        */
  
  				if (disabled) {

  #ifdef IP_USE_DISABLE

  					if (irq > 4) {
  						disabled = 0;
  						enable_irq(irq);
  					}

  #else

  					disabled = 0;
  					/*printk("reenabling irq %d
  ", irq); */

  #endif

  				}

  // used to do 'goto repeat;' here, this delayed bh processing too long

  				return;
  			}
  		}
  		if (mer && ccleirq > 0 && !aliased_irq) {
  			printk("ISA interrupt from unknown source? EIRQ_REG = %x
  ",mer);
  			ccleirq--;
  		}

  	}

   iirq:
  	mir = master_inb(IIRQ_REG);
  	/* should test whether keyboard irq is really enabled, doing it in defhand */
  	if (mir & Q40_IRQ_KEYB_MASK)

  		do_IRQ(Q40_IRQ_KEYBOARD, fp);

  	return;

  }

  void q40_irq_enable(struct irq_data *data)

  {

  	unsigned int irq = data->irq;

  	if (irq >= 5 && irq <= 15) {
  		mext_disabled--;
  		if (mext_disabled > 0)

  			printk("q40_irq_enable : nested disable/enable
  ");

  		if (mext_disabled == 0)
  			master_outb(1, EXT_ENABLE_REG);
  	}

  }

  void q40_irq_disable(struct irq_data *data)

  {

  	unsigned int irq = data->irq;

  	/* disable ISA iqs : only do something if the driver has been
  	 * verified to be Q40 "compatible" - right now IDE, NE2K
  	 * Any driver should not attempt to sleep across disable_irq !!
  	 */
  
  	if (irq >= 5 && irq <= 15) {
  		master_outb(0, EXT_ENABLE_REG);
  		mext_disabled++;
  		if (mext_disabled > 1)
  			printk("disable_irq nesting count %d
  ",mext_disabled);
  	}

  }