/*	$NetBSD: sio_pic.c,v 1.3 1995/12/24 02:29:49 mycroft Exp $	*/

/*
 * Copyright (c) 1995 Carnegie-Mellon University.
 * All rights reserved.
 *
 * Author: Chris G. Demetriou
 * 
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/malloc.h>
#include <sys/syslog.h>

#include <dev/isa/isareg.h>
#include <dev/isa/isavar.h>
#include <alpha/pci/siovar.h>

#ifndef EVCNT_COUNTERS
#include <machine/intrcnt.h>
#endif

#include "sio.h"

/*
 * To add to the long history of wonderful PROM console traits,
 * AlphaStation PROMs don't reset themselves completely on boot!
 * Therefore, if an interrupt was turned on when the kernel was
 * started, we're not going to EVER turn it off...  I don't know
 * what will happen if new interrupts (that the PROM console doesn't
 * want) are turned on.  I'll burn that bridge when I come to it.
 */
#define	BROKEN_PROM_CONSOLE

/*
 * Private functions and variables.
 */
static void	*sio_intr_establish __P((void *, isa_irq_t,
		    int, int, int (*)(void *), void *));
static void	sio_intr_disestablish __P((void *, void *));
static void	sio_strayintr __P((isa_irq_t));

static __const struct isa_pio_fns *sio_ipf;		/* XXX */
static void *sio_ipfa;					/* XXX */

void		sio_intr_setup __P((__const struct isa_pio_fns *, void *));
void		sio_iointr __P((void *framep, int vec));

struct	isa_intr_fns sio_isa_intr_fns = {
	sio_intr_establish,
	sio_intr_disestablish,
};

/*
 * Interrupt handler chains.  sio_intr_establish() inserts a handler into
 * the list.  The handler is called with its (single) argument.
 */
struct intrhand {
	int	(*ih_fun)();
	void	*ih_arg;
	u_long	ih_count;
	struct	intrhand *ih_next;
	int	ih_level;
	int	ih_irq;
};

#define	ICU_LEN		16		/* number of ISA IRQs */

static struct intrhand *sio_intrhand[ICU_LEN];
static int sio_intrsharetype[ICU_LEN];
static u_long sio_strayintrcnt[ICU_LEN];
#ifdef EVCNT_COUNTERS
struct evcnt sio_intr_evcnt;
#endif

#ifndef STRAY_MAX
#ifdef BROKEN_PROM_CONSOLE
/*
 * If prom console is broken, because initial interrupt settings
 * must be kept, there's no way to escape stray interrupts.
 */
#define	STRAY_MAX	0
#else
#define	STRAY_MAX	5
#endif
#endif

#ifdef BROKEN_PROM_CONSOLE
/*
 * If prom console is broken, must remember the initial interrupt
 * settings and enforce them.  WHEE!
 */
u_int8_t initial_ocw1[2];
u_int8_t initial_elcr[2];
#define	INITIALLY_ENABLED(irq) \
	    ((initial_ocw1[(irq) / 8] & (1 << ((irq) % 8))) == 0)
#define	INITIALLY_LEVEL_TRIGGERED(irq) \
	    ((initial_elcr[(irq) / 8] & (1 << ((irq) % 8))) != 0)
#else
#define	INITIALLY_ENABLED(irq)		((irq) == 2 ? 1 : 0)
#define	INITIALLY_LEVEL_TRIGGERED(irq)	0
#endif

void
sio_setirqstat(irq, enabled, type)
	int irq, enabled;
	int type;
{
	u_int8_t ocw1[2], elcr[2];
	int icu, bit;

#if 0
	printf("sio_setirqstat: irq %d, %s, %s\n", irq,
	    enabled ? "enabled" : "disabled", isa_intr_typename(type));
#endif

	sio_intrsharetype[irq] = type;

	icu = irq / 8;
	bit = irq % 8;

	ocw1[0] = INB(sio_ipf, sio_ipfa, IO_ICU1 + 1);
	ocw1[1] = INB(sio_ipf, sio_ipfa, IO_ICU2 + 1);
	elcr[0] = INB(sio_ipf, sio_ipfa, 0x4d0);		/* XXX */
	elcr[1] = INB(sio_ipf, sio_ipfa, 0x4d1);		/* XXX */

	/*
	 * interrupt enable: set bit to mask (disable) interrupt.
	 */
	if (enabled)
		ocw1[icu] &= ~(1 << bit);
	else
		ocw1[icu] |= 1 << bit;

	/*
	 * interrupt type select: set bit to get level-triggered.
	 */
	if (type == IST_LEVEL)
		elcr[icu] |= 1 << bit;
	else
		elcr[icu] &= ~(1 << bit);

#ifdef not_here
	/* see the init function... */
	ocw1[0] &= ~0x04;		/* always enable IRQ2 on first PIC */
	elcr[0] &= ~0x07;		/* IRQ[0-2] must be edge-triggered */
	elcr[1] &= ~0x21;		/* IRQ[13,8] must be edge-triggered */
#endif

#ifdef BROKEN_PROM_CONSOLE
	/*
	 * make sure that the initially clear bits (unmasked interrupts)
	 * are never set, and that the initially-level-triggered
	 * intrrupts always remain level-triggered, to keep the prom happy.
	 */
	if ((ocw1[0] & ~initial_ocw1[0]) != 0 ||
	    (ocw1[1] & ~initial_ocw1[1]) != 0 ||
	    (elcr[0] & initial_elcr[0]) != initial_elcr[0] ||
	    (elcr[1] & initial_elcr[1]) != initial_elcr[1]) {
		printf("sio_sis: initial: ocw = (%2x,%2x), elcr = (%2x,%2X)\n",
		    initial_ocw1[0], initial_ocw1[1],
		    initial_elcr[0], initial_elcr[1]);
		printf("         current: ocw = (%2x,%2x), elcr = (%2x,%2X)\n",
		    ocw1[0], ocw1[1], elcr[0], elcr[1]);
		panic("sio_setirqstat: hosed");
	}
#endif

	OUTB(sio_ipf, sio_ipfa, IO_ICU1 + 1, ocw1[0]);
	OUTB(sio_ipf, sio_ipfa, IO_ICU2 + 1, ocw1[1]);
	OUTB(sio_ipf, sio_ipfa, 0x4d0, elcr[0]);		/* XXX */
	OUTB(sio_ipf, sio_ipfa, 0x4d1, elcr[1]);		/* XXX */
}

void
sio_intr_setup(ipf, ipfa)
	__const struct isa_pio_fns *ipf;
	void *ipfa;
{
	int i;

	sio_ipf = ipf;
	sio_ipfa = ipfa;

#ifdef BROKEN_PROM_CONSOLE
	/*
	 * Remember the initial values, because the prom is stupid.
	 */
	initial_ocw1[0] = INB(sio_ipf, sio_ipfa, IO_ICU1 + 1);
	initial_ocw1[1] = INB(sio_ipf, sio_ipfa, IO_ICU2 + 1);
	initial_elcr[0] = INB(sio_ipf, sio_ipfa, 0x4d0);	/* XXX */
	initial_elcr[1] = INB(sio_ipf, sio_ipfa, 0x4d1);	/* XXX */
#if 0
	printf("initial_ocw1[0] = 0x%x\n", initial_ocw1[0]);
	printf("initial_ocw1[1] = 0x%x\n", initial_ocw1[1]);
	printf("initial_elcr[0] = 0x%x\n", initial_elcr[0]);
	printf("initial_elcr[1] = 0x%x\n", initial_elcr[1]);
#endif
#endif

	/*
	 * set up initial values for interrupt enables.
	 */
	for (i = 0; i < ICU_LEN; i++) {
		switch (i) {
		case 0:
		case 1:
		case 8:
		case 13:
			/*
			 * IRQs 0, 1, 8, and 13 must always be
			 * edge-triggered.
			 */
			if (INITIALLY_LEVEL_TRIGGERED(i))
				printf("sio_intr_setup: %d LT!\n", i);
			sio_setirqstat(i, INITIALLY_ENABLED(i), IST_EDGE);
			break;

		case 2:
			/*
			 * IRQ 2 must be edge-triggered, and should be
			 * enabled (otherwise IRQs 8-15 are ignored).
			 */
			if (INITIALLY_LEVEL_TRIGGERED(i))
				printf("sio_intr_setup: %d LT!\n", i);
			if (!INITIALLY_ENABLED(i))
				printf("sio_intr_setup: %d not enabled!\n", i);
			sio_setirqstat(i, 1, IST_EDGE);
			break;

		default:
			/*
			 * Otherwise, disable the IRQ and set its
			 * type to (effectively) "unknown."
			 */
			sio_setirqstat(i, INITIALLY_ENABLED(i),
			    INITIALLY_LEVEL_TRIGGERED(i) ? IST_LEVEL :
				IST_NONE);
			break;
		}
	}
}

void *
sio_intr_establish(siifa, irq, type, level, ih_fun, ih_arg)
	void *siifa;
        isa_irq_t irq;
        int type;
        int level;
        int (*ih_fun)(void *);
        void *ih_arg;
{
	struct intrhand **p, *c, *ih;
	extern int cold;

	/* no point in sleeping unless someone can free memory. */
	ih = malloc(sizeof *ih, M_DEVBUF, cold ? M_NOWAIT : M_WAITOK);
	if (ih == NULL)
		panic("sio_intr_establish: can't malloc handler info");

	if (irq > ICU_LEN || type == IST_NONE)
		panic("sio_intr_establish: bogus irq or type");

	switch (sio_intrsharetype[irq]) {
	case IST_EDGE:
	case IST_LEVEL:
		if (type == sio_intrsharetype[irq])
			break;
	case IST_PULSE:
		if (type != IST_NONE)
			panic("intr_establish: can't share %s with %s",
			    isa_intrsharetype_name(sio_intrsharetype[irq]),
			    isa_intrsharetype_name(type));
		break;
        }

	/*
	 * Figure out where to put the handler.
	 * This is O(N^2), but we want to preserve the order, and N is
	 * generally small.
	 */
	for (p = &sio_intrhand[irq]; (c = *p) != NULL; p = &c->ih_next)
		;

	/*
	 * Poke the real handler in now.
	 */
	ih->ih_fun = ih_fun;
	ih->ih_arg = ih_arg;
	ih->ih_count = 0;
	ih->ih_next = NULL;
	ih->ih_level = 0;			/* XXX meaningless on alpha */
	ih->ih_irq = irq;
	*p = ih;

	sio_setirqstat(irq, 1, type);

	return ih;
}

void
sio_intr_disestablish(siifa, handler)
	void *siifa;
	void *handler;
{

	printf("sio_intr_disestablish(%lx)\n", handler);
	/* XXX */

	/* XXX NEVER ALLOW AN INITIALLY-ENABLED INTERRUPT TO BE DISABLED */
	/* XXX NEVER ALLOW AN INITIALLY-LT INTERRUPT TO BECOME UNTYPED */
}

/*
 * caught a stray interrupt; notify if not too many seen already.
 */
void
sio_strayintr(irq)
	isa_irq_t irq;
{

	if (++sio_strayintrcnt[irq] <= STRAY_MAX)
		log(LOG_ERR, "stray interrupt %d%s\n", irq,
		    sio_strayintrcnt[irq] >= STRAY_MAX ?
			"; stopped logging" : "");
}

void
sio_iointr(framep, vec)
	void *framep;
	int vec;
{
	int irq, handled;
	struct intrhand *ih;

	irq = (vec - 0x800) >> 4;
#ifdef DIAGNOSTIC
	if (irq > ICU_LEN || irq < 0)
		panic("sio_iointr: irq out of range (%d)", irq);
#endif

#ifdef EVCNT_COUNTERS
	sio_intr_evcnt.ev_count++;
#else
	if (ICU_LEN != INTRCNT_ISA_IRQ_LEN)
		panic("sio interrupt counter sizes inconsistent");
	intrcnt[INTRCNT_ISA_IRQ + irq]++;
#endif

	/*
	 * We cdr down the intrhand chain, calling each handler with
	 * its appropriate argument;
	 *
	 * The handler returns one of three values:
	 *   0 - This interrupt wasn't for me.
	 *   1 - This interrupt was for me.
	 *  -1 - This interrupt might have been for me, but I don't know.
	 * If there are no handlers, or they all return 0, we flags it as a
	 * `stray' interrupt.  On a system with level-triggered interrupts,
	 * we could terminate immediately when one of them returns 1; but
	 * this is PC-ish!
	 */
	for (ih = sio_intrhand[irq], handled = 0; ih != NULL;
	    ih = ih->ih_next) {
		int rv;

		rv = (*ih->ih_fun)(ih->ih_arg);

		ih->ih_count++;
		handled = handled || (rv != 0);
	}

	if (!handled)
		sio_strayintr(irq);

	/*
	 * Some versions of the machines which use the SIO
	 * (or is it some PALcode revisions on those machines?)
	 * require the non-specific EOI to be fed to the PIC(s)
	 * by the interrupt handler.
	 */
	if (irq > 7)
		OUTB(sio_ipf, sio_ipfa,
		    IO_ICU2 + 0, 0x20 | (irq & 0x07));		/* XXX */
	OUTB(sio_ipf, sio_ipfa,
	    IO_ICU1 + 0, 0x20 | (irq > 7 ? 2 : irq));		/* XXX */
}