/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (C) 2002 Benno Rice <benno@FreeBSD.org>
 * All rights reserved.
 *
 * 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 Benno Rice ``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 TOOLS GMBH 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/param.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/kernel.h>
#include <sys/kthread.h>
#include <sys/linker.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/proc.h>

#include <geom/geom.h>

#include <dev/ofw/openfirm.h>

#define OFWD_BLOCKSIZE  512

struct ofwd_softc
{
        struct bio_queue_head ofwd_bio_queue;
        struct mtx      ofwd_queue_mtx;
        ihandle_t       ofwd_instance;
        off_t           ofwd_mediasize;
        unsigned        ofwd_sectorsize;
        unsigned        ofwd_fwheads;
        unsigned        ofwd_fwsectors;
        struct proc     *ofwd_procp;
        struct g_geom   *ofwd_gp;
        struct g_provider *ofwd_pp;
} ofwd_softc;

static g_init_t g_ofwd_init;
static g_start_t g_ofwd_start;
static g_access_t g_ofwd_access;

struct g_class g_ofwd_class = {
        .name = "OFWD",
        .version = G_VERSION,
        .init = g_ofwd_init,
        .start = g_ofwd_start,
        .access = g_ofwd_access,
};

DECLARE_GEOM_CLASS(g_ofwd_class, g_ofwd);

static int ofwd_enable = 0;
TUNABLE_INT("kern.ofw.disk", &ofwd_enable);

static int
ofwd_startio(struct ofwd_softc *sc, struct bio *bp)
{
        u_int r;

        r = OF_seek(sc->ofwd_instance, bp->bio_offset);

        switch (bp->bio_cmd) {
        case BIO_READ:
                r = OF_read(sc->ofwd_instance, (void *)bp->bio_data,
                   bp->bio_length);
                break;
        case BIO_WRITE:
                r = OF_write(sc->ofwd_instance, (void *)bp->bio_data,
                   bp->bio_length);
                break;
        }
        if (r != bp->bio_length)
                panic("ofwd: incorrect i/o count");

        bp->bio_resid = 0;
        return (0);
}

static void
ofwd_kthread(void *arg)
{
        struct ofwd_softc *sc;
        struct bio *bp;
        int error;

        sc = arg;
        curthread->td_base_pri = PRIBIO;

        for (;;) {
                mtx_lock(&sc->ofwd_queue_mtx);
                bp = bioq_takefirst(&sc->ofwd_bio_queue);
                if (!bp) {
                        msleep(sc, &sc->ofwd_queue_mtx, PRIBIO | PDROP,
                            "ofwdwait", 0);
                        continue;
                }
                mtx_unlock(&sc->ofwd_queue_mtx);
                if (bp->bio_cmd == BIO_GETATTR) {
                        error = EOPNOTSUPP;
                } else
                        error = ofwd_startio(sc, bp);

                if (error != -1) {
                        bp->bio_completed = bp->bio_length;
                        g_io_deliver(bp, error);
                }
        }
}

static void
g_ofwd_init(struct g_class *mp __unused)
{
        char path[128];
        char fname[32];
        phandle_t ofd;
        struct ofwd_softc *sc;
        struct g_geom *gp;
        struct g_provider *pp;
        ihandle_t ifd;
        int error;

        if (ofwd_enable == 0)
                return;

        ofd = OF_finddevice("ofwdisk");
        if (ofd == -1)
                return;

        bzero(path, 128);
        OF_package_to_path(ofd, path, 128);
        OF_getprop(ofd, "file", fname, sizeof(fname));
        printf("ofw_disk located at %s, file %s\n", path, fname);
        ifd = OF_open(path);
        if (ifd == -1) {
                printf("ofw_disk: could not create instance\n");
                return;
        }

        sc = (struct ofwd_softc *)malloc(sizeof *sc, M_DEVBUF,
            M_WAITOK | M_ZERO);
        bioq_init(&sc->ofwd_bio_queue);
        mtx_init(&sc->ofwd_queue_mtx, "ofwd bio queue", NULL, MTX_DEF);
        sc->ofwd_instance = ifd;
        sc->ofwd_mediasize = (off_t)2 * 33554432;
        sc->ofwd_sectorsize = OFWD_BLOCKSIZE;
        sc->ofwd_fwsectors = 0;
        sc->ofwd_fwheads = 0;
        error = kproc_create(ofwd_kthread, sc, &sc->ofwd_procp, 0, 0,
            "ofwd0");
        if (error != 0) {
                free(sc, M_DEVBUF);
                return;
        }

        gp = g_new_geomf(&g_ofwd_class, "ofwd0");
        gp->softc = sc;
        pp = g_new_providerf(gp, "ofwd0");
        pp->mediasize = sc->ofwd_mediasize;
        pp->sectorsize = sc->ofwd_sectorsize;
        sc->ofwd_gp = gp;
        sc->ofwd_pp = pp;
        g_error_provider(pp, 0);
}

static void
g_ofwd_start(struct bio *bp)
{
        struct ofwd_softc *sc;

        sc = bp->bio_to->geom->softc;
        mtx_lock(&sc->ofwd_queue_mtx);
        bioq_disksort(&sc->ofwd_bio_queue, bp);
        mtx_unlock(&sc->ofwd_queue_mtx);
        wakeup(sc);
}

static int
g_ofwd_access(struct g_provider *pp, int r, int w, int e)
{

        if (pp->geom->softc == NULL)
                return (ENXIO);
        return (0);
}