/*      $NetBSD: virtctrl.c,v 1.2 2024/01/06 21:49:59 thorpej Exp $     */

/*-
 * Copyright (c) 2024 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: virtctrl.c,v 1.2 2024/01/06 21:49:59 thorpej Exp $");

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

#include <machine/cpu.h>

#include <virt68k/dev/mainbusvar.h>

struct virtctrl_softc {
        device_t                sc_dev;
        bus_space_tag_t         sc_bst;
        bus_space_handle_t      sc_bsh;
};

static const struct device_compatible_entry compat_data[] = {
        { .compat = "netbsd,qemu-virt-ctrl" },
        DEVICE_COMPAT_EOL
};

#define VIRTCTRL_REG_FEATURES   0x00
#define VIRTCTRL_REG_CMD        0x04

#define CMD_NOP                 0
#define CMD_RESET               1
#define CMD_HALT                2
#define CMD_PANIC               3

#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))

static void
virtctrl_reset_handler(void *v, int howto)
{
        struct virtctrl_softc * const sc = v;

        if (panicstr != NULL) {
                /*
                 * XXX N.B. This forces a shutdown, rather than
                 * XXX a reboot.
                 */
                REG_WRITE(sc, VIRTCTRL_REG_CMD, CMD_PANIC);
        } else if (howto & RB_HALT) {
                REG_WRITE(sc, VIRTCTRL_REG_CMD, CMD_HALT);
        } else {
                REG_WRITE(sc, VIRTCTRL_REG_CMD, CMD_RESET);
        }
}

static int
virtctrl_match(device_t parent, cfdata_t cf, void *aux)
{
        struct mainbus_attach_args * const ma = aux;

        return mainbus_compatible_match(ma, compat_data);
}

static void
virtctrl_attach(device_t parent, device_t self, void *aux)
{
        struct virtctrl_softc * const sc = device_private(self);
        struct mainbus_attach_args * const ma = aux;
        uint32_t feat;

        sc->sc_dev = self;
        sc->sc_bst = ma->ma_st;
        if (bus_space_map(sc->sc_bst, ma->ma_addr, ma->ma_size, 0,
                          &sc->sc_bsh) != 0) {
                aprint_error(": couldn't map registers\n");
                return;
        }

        aprint_naive("\n");
        aprint_normal(": Qemu Virtual System Controller\n");

        feat = REG_READ(sc, VIRTCTRL_REG_FEATURES);
        aprint_normal_dev(self, "features=0x%08x\n", feat);

        cpu_set_reset_func(virtctrl_reset_handler, sc);
}

CFATTACH_DECL_NEW(virtctrl, sizeof(struct virtctrl_softc),
        virtctrl_match, virtctrl_attach, NULL, NULL);