/*      $NetBSD: gfpic.c,v 1.2 2024/04/24 14:41:13 thorpej Exp $        */

/*-
* Copyright (c) 2023 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

/*
* Support for the Goldfish virtual Programmable Interrupt Controller.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: gfpic.c,v 1.2 2024/04/24 14:41:13 thorpej Exp $");

#include <sys/types.h>
#include <sys/systm.h>
#include <sys/bus.h>

#include <dev/goldfish/gfpicvar.h>

/*
* Goldfish PIC registers.
*/
#define GFPIC_STATUS            (0 << 2) /* pending interrupt count */
#define GFPIC_PENDING           (1 << 2) /* pending interrupt bitmask */
#define GFPIC_DISABLE_ALL       (2 << 2) /* disables / clears all interrupts */
#define GFPIC_DISABLE           (3 << 2) /* disable IRQs (bitmask) */
#define GFPIC_ENABLE            (4 << 2) /* enable IRQs (bitmask) */

#define REG_READ(sc, r)         \
       bus_space_read_4((sc)->sc_bst, (sc)->sc_bsh, (r))
#define REG_WRITE(sc, r, v)     \
       bus_space_write_4((sc)->sc_bst, (sc)->sc_bsh, (r), (v))

/*
* gfpic_attach --
*      Attach a Goldfish virtual PIC.
*/
void
gfpic_attach(struct gfpic_softc *sc)
{
       aprint_naive("\n");
       aprint_normal(": Google Goldfish PIC\n");

       REG_WRITE(sc, GFPIC_DISABLE_ALL, 0);
}

/*
* gfpic_enable --
*      Enable the specified IRQ on a Goldfish virtual PIC.
*/
void
gfpic_enable(struct gfpic_softc *sc, int pirq)
{
       KASSERT(pirq >= 0);
       KASSERT(pirq <= 31);

       REG_WRITE(sc, GFPIC_ENABLE, (1U << pirq));
}

/*
* gfpic_disable --
*      Disable the specified IRQ on a Goldfish virtual PIC.
*/
void
gfpic_disable(struct gfpic_softc *sc, int pirq)
{
       KASSERT(pirq >= 0);
       KASSERT(pirq <= 31);

       REG_WRITE(sc, GFPIC_DISABLE, (1U << pirq));
}

/*
* gfpic_pending --
*      Return the next pending IRQ on a Goldfish virtual PIC,
*      or -1 if there are none.
*/
int
gfpic_pending(struct gfpic_softc *sc)
{
       return ffs(REG_READ(sc, GFPIC_PENDING)) - 1;
}