ataints.c

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 * Returns:	Nothing
 *
 * This function should be called during kernel startup to initialize
 * the atari IRQ handling routines.
 */

void __init atari_init_IRQ(void)
{
	int i;

	/* initialize the vector table */
	for (i = 0; i < NUM_INT_SOURCES; ++i) {
		vectors[IRQ_SOURCE_TO_VECTOR(i)] = bad_interrupt;
	}

	/* Initialize the MFP(s) */

#ifdef ATARI_USE_SOFTWARE_EOI
	mfp.vec_adr  = 0x48;	/* Software EOI-Mode */
#else
	mfp.vec_adr  = 0x40;	/* Automatic EOI-Mode */
#endif
	mfp.int_en_a = 0x00;	/* turn off MFP-Ints */
	mfp.int_en_b = 0x00;
	mfp.int_mk_a = 0xff;	/* no Masking */
	mfp.int_mk_b = 0xff;

	if (ATARIHW_PRESENT(TT_MFP)) {
#ifdef ATARI_USE_SOFTWARE_EOI
		tt_mfp.vec_adr  = 0x58;		/* Software EOI-Mode */
#else
		tt_mfp.vec_adr  = 0x50;		/* Automatic EOI-Mode */
#endif
		tt_mfp.int_en_a = 0x00;		/* turn off MFP-Ints */
		tt_mfp.int_en_b = 0x00;
		tt_mfp.int_mk_a = 0xff;		/* no Masking */
		tt_mfp.int_mk_b = 0xff;
	}

	if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
		scc.cha_a_ctrl = 9;
		MFPDELAY();
		scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
	}

	if (ATARIHW_PRESENT(SCU)) {
		/* init the SCU if present */
		tt_scu.sys_mask = 0x10;		/* enable VBL (for the cursor) and
									 * disable HSYNC interrupts (who
									 * needs them?)  MFP and SCC are
									 * enabled in VME mask
									 */
		tt_scu.vme_mask = 0x60;		/* enable MFP and SCC ints */
	}
	else {
		/* If no SCU and no Hades, the HSYNC interrupt needs to be
		 * disabled this way. (Else _inthandler in kernel/sys_call.S
		 * gets overruns)
		 */

		if (!MACH_IS_HADES)
			vectors[VEC_INT2] = falcon_hblhandler;
	}

	if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
		/* Initialize the LM1992 Sound Controller to enable
		   the PSG sound.  This is misplaced here, it should
		   be in an atasound_init(), that doesn't exist yet. */
		atari_microwire_cmd(MW_LM1992_PSG_HIGH);
	}
	
	stdma_init();

	/* Initialize the PSG: all sounds off, both ports output */
	sound_ym.rd_data_reg_sel = 7;
	sound_ym.wd_data = 0xff;
}


static void atari_call_irq_list( int irq, void *dev_id, struct pt_regs *fp )
{
	irq_node_t *node;

	for (node = (irq_node_t *)dev_id; node; node = node->next)
		node->handler(irq, node->dev_id, fp);
}


/*
 * atari_request_irq : add an interrupt service routine for a particular
 *                     machine specific interrupt source.
 *                     If the addition was successful, it returns 0.
 */

int atari_request_irq(unsigned int irq, void (*handler)(int, void *, struct pt_regs *),
                      unsigned long flags, const char *devname, void *dev_id)
{
	int vector;
	unsigned long oflags = flags;

	/*
	 * The following is a hack to make some PCI card drivers work,
	 * which set the SA_SHIRQ flag.
	 */

	flags &= ~SA_SHIRQ;

	if (flags == SA_INTERRUPT) {
		printk ("%s: SA_INTERRUPT changed to IRQ_TYPE_SLOW for %s\n",
			__FUNCTION__, devname);
		flags = IRQ_TYPE_SLOW;
	}
	if (flags < IRQ_TYPE_SLOW || flags > IRQ_TYPE_PRIO) {
		printk ("%s: Bad irq type 0x%lx <0x%lx> requested from %s\n",
		        __FUNCTION__, flags, oflags, devname);
		return -EINVAL;
	}
	if (!IS_VALID_INTNO(irq)) {
		printk ("%s: Unknown irq %d requested from %s\n",
		        __FUNCTION__, irq, devname);
		return -ENXIO;
	}
	vector = IRQ_SOURCE_TO_VECTOR(irq);

	/*
	 * Check type/source combination: slow ints are (currently)
	 * only possible for MFP-interrupts.
	 */
	if (flags == IRQ_TYPE_SLOW &&
		(irq < STMFP_SOURCE_BASE || irq >= SCC_SOURCE_BASE)) {
		printk ("%s: Slow irq requested for non-MFP source %d from %s\n",
		        __FUNCTION__, irq, devname);
		return -EINVAL;
	}
		
	if (vectors[vector] == bad_interrupt) {
		/* int has no handler yet */
		irq_handler[irq].handler = handler;
		irq_handler[irq].dev_id  = dev_id;
		irq_param[irq].flags   = flags;
		irq_param[irq].devname = devname;
		vectors[vector] =
			(flags == IRQ_TYPE_SLOW) ? slow_handlers[irq-STMFP_SOURCE_BASE] :
			(flags == IRQ_TYPE_FAST) ? atari_fast_irq_handler :
			                          atari_prio_irq_handler;
		/* If MFP int, also enable and umask it */
		atari_turnon_irq(irq);
		atari_enable_irq(irq);

		return 0;
	}
	else if (irq_param[irq].flags == flags) {
		/* old handler is of same type -> handlers can be chained */
		irq_node_t *node;
		unsigned long flags;

		save_flags(flags);
		cli();

		if (irq_handler[irq].handler != atari_call_irq_list) {
			/* Only one handler yet, make a node for this first one */
			if (!(node = new_irq_node()))
				return -ENOMEM;
			node->handler = irq_handler[irq].handler;
			node->dev_id  = irq_handler[irq].dev_id;
			node->devname = irq_param[irq].devname;
			node->next = NULL;

			irq_handler[irq].handler = atari_call_irq_list;
			irq_handler[irq].dev_id  = node;
			irq_param[irq].devname   = "chained";
		}

		if (!(node = new_irq_node()))
			return -ENOMEM;
		node->handler = handler;
		node->dev_id  = dev_id;
		node->devname = devname;
		/* new handlers are put in front of the queue */
		node->next = irq_handler[irq].dev_id;
		irq_handler[irq].dev_id = node;

		restore_flags(flags);
		return 0;
	} else {
		printk ("%s: Irq %d allocated by other type int (call from %s)\n",
		        __FUNCTION__, irq, devname);
		return -EBUSY;
	}
}

void atari_free_irq(unsigned int irq, void *dev_id)
{
	unsigned long flags;
	int vector;
	irq_node_t **list, *node;

	if (!IS_VALID_INTNO(irq)) {
		printk("%s: Unknown irq %d\n", __FUNCTION__, irq);
		return;
	}

	vector = IRQ_SOURCE_TO_VECTOR(irq);
	if (vectors[vector] == bad_interrupt)
		goto not_found;

	save_flags(flags);
	cli();

	if (irq_handler[irq].handler != atari_call_irq_list) {
		/* It's the only handler for the interrupt */
		if (irq_handler[irq].dev_id != dev_id) {
			restore_flags(flags);
			goto not_found;
		}
		irq_handler[irq].handler = NULL;
		irq_handler[irq].dev_id  = NULL;
		irq_param[irq].devname   = NULL;
		vectors[vector] = bad_interrupt;
		/* If MFP int, also disable it */
		atari_disable_irq(irq);
		atari_turnoff_irq(irq);

		restore_flags(flags);
		return;
	}

	/* The interrupt is chained, find the irq on the list */
	for(list = (irq_node_t **)&irq_handler[irq].dev_id; *list; list = &(*list)->next) {
		if ((*list)->dev_id == dev_id) break;
	}
	if (!*list) {
		restore_flags(flags);
		goto not_found;
	}

	(*list)->handler = NULL; /* Mark it as free for reallocation */
	*list = (*list)->next;

	/* If there's now only one handler, unchain the interrupt, i.e. plug in
	 * the handler directly again and omit atari_call_irq_list */
	node = (irq_node_t *)irq_handler[irq].dev_id;
	if (node && !node->next) {
		irq_handler[irq].handler = node->handler;
		irq_handler[irq].dev_id  = node->dev_id;
		irq_param[irq].devname   = node->devname;
		node->handler = NULL; /* Mark it as free for reallocation */
	}

	restore_flags(flags);
	return;

not_found:
	printk("%s: tried to remove invalid irq\n", __FUNCTION__);
	return;
}


/*
 * atari_register_vme_int() returns the number of a free interrupt vector for
 * hardware with a programmable int vector (probably a VME board).
 */

unsigned long atari_register_vme_int(void)
{
	int i;

	for(i = 0; i < 32; i++)
		if((free_vme_vec_bitmap & (1 << i)) == 0)
			break;
	
	if(i == 16)
		return 0;

	free_vme_vec_bitmap |= 1 << i;
	return (VME_SOURCE_BASE + i);
}


void atari_unregister_vme_int(unsigned long irq)
{
	if(irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
		irq -= VME_SOURCE_BASE;
		free_vme_vec_bitmap &= ~(1 << irq);
	}
}


int atari_get_irq_list(char *buf)
{
	int i, len = 0;

	for (i = 0; i < NUM_INT_SOURCES; ++i) {
		if (vectors[IRQ_SOURCE_TO_VECTOR(i)] == bad_interrupt)
			continue;
		if (i < STMFP_SOURCE_BASE)
			len += sprintf(buf+len, "auto %2d: %10u ",
				       i, kstat.irqs[0][i]);
		else
			len += sprintf(buf+len, "vec $%02x: %10u ",
				       IRQ_SOURCE_TO_VECTOR(i),
				       kstat.irqs[0][i]);

		if (irq_handler[i].handler != atari_call_irq_list) {
			len += sprintf(buf+len, "%s\n", irq_param[i].devname);
		}
		else {
			irq_node_t *p;
			for( p = (irq_node_t *)irq_handler[i].dev_id; p; p = p->next ) {
				len += sprintf(buf+len, "%s\n", p->devname);
				if (p->next)
					len += sprintf( buf+len, "                    " );
			}
		}
	}
	if (num_spurious)
		len += sprintf(buf+len, "spurio.: %10u\n", num_spurious);
	
	return len;
}