/* $NetBSD: ld_thunkbus.c,v 1.34 2025/04/13 02:34:02 rin Exp $ */

/*-
 * Copyright (c) 2011 Jared D. McNeill <jmcneill@invisible.ca>
 * 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 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: ld_thunkbus.c,v 1.34 2025/04/13 02:34:02 rin Exp $");

#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/device.h>
#include <sys/buf.h>
#include <sys/bufq.h>
#include <sys/disk.h>
#include <sys/kmem.h>

#include <dev/ldvar.h>

#include <machine/mainbus.h>
#include <machine/thunk.h>
#include <machine/intr.h>

static int      ld_thunkbus_match(device_t, cfdata_t, void *);
static void     ld_thunkbus_attach(device_t, device_t, void *);

static int      ld_thunkbus_ldstart(struct ld_softc *, struct buf *);
static int      ld_thunkbus_lddump(struct ld_softc *, void *, daddr_t, int);
static int      ld_thunkbus_ioctl(struct ld_softc *, u_long, void *, int32_t, bool);

//#define LD_USE_AIO

#ifdef LD_USE_AIO
static int      ld_aio_sig(void *);
#endif
static void     ld_thunkbus_complete(void *arg);

struct ld_thunkbus_softc;

struct ld_thunkbus_transfer {
        struct ld_thunkbus_softc *tt_sc;
        struct aiocb    tt_aio;
        struct buf      *tt_bp;
};

struct ld_thunkbus_softc {
        struct ld_softc sc_ld;

        int             sc_fd;
        void            *sc_ih;
        void            *sc_aio_ih;

        struct ld_thunkbus_transfer sc_tt;
        bool            busy;
};

CFATTACH_DECL_NEW(ld_thunkbus, sizeof(struct ld_thunkbus_softc),
    ld_thunkbus_match, ld_thunkbus_attach, NULL, NULL);

static int
ld_thunkbus_match(device_t parent, cfdata_t match, void *opaque)
{
        struct thunkbus_attach_args *taa = opaque;

        if (taa->taa_type != THUNKBUS_TYPE_DISKIMAGE)
                return 0;

        return 1;
}

static void
ld_thunkbus_attach(device_t parent, device_t self, void *opaque)
{
        struct ld_thunkbus_softc *sc = device_private(self);
        struct ld_softc *ld = &sc->sc_ld;
        struct thunkbus_attach_args *taa = opaque;
        const char *path = taa->u.diskimage.path;
        ssize_t blksize;
        off_t size;

        ld->sc_dv = self;

        sc->sc_fd = thunk_open(path, O_RDWR, 0);
        if (sc->sc_fd == -1) {
                aprint_error(": couldn't open %s: %d\n", path, thunk_geterrno());
                return;
        }
        if (thunk_fstat_getsize(sc->sc_fd, &size, &blksize) == -1) {
                aprint_error(": couldn't stat %s: %d\n", path, thunk_geterrno());
                return;
        }

        aprint_naive("\n");
        aprint_normal(": %s (%lld)\n", path, (long long)size);

        ld->sc_flags = LDF_ENABLED;
        ld->sc_maxxfer = MAXPHYS;
        ld->sc_secsize = 512;
        ld->sc_secperunit = size / ld->sc_secsize;
        ld->sc_maxqueuecnt = 1;
        ld->sc_start = ld_thunkbus_ldstart;
        ld->sc_dump = ld_thunkbus_lddump;
        ld->sc_ioctl = ld_thunkbus_ioctl;

        sc->sc_ih = softint_establish(SOFTINT_BIO,
            ld_thunkbus_complete, ld);

#ifdef LD_USE_AIO
        sc->sc_aio_ih = sigio_intr_establish(ld_aio_sig, sc);
        if (sc->sc_aio_ih == NULL)
                panic("couldn't establish aio sig interrupt");
#endif

        sc->busy = false;

        ldattach(ld, BUFQ_DISK_DEFAULT_STRAT);
}

#ifdef LD_USE_AIO
static int
ld_aio_sig(void *arg)
{
        struct ld_softc *ld = arg;
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;

        softint_schedule(sc->sc_ih);

        return 0;
}

static int
ld_thunkbus_ldstart(struct ld_softc *ld, struct buf *bp)
{
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;
        struct ld_thunkbus_transfer *tt = &sc->sc_tt;
        off_t offset = bp->b_rawblkno * ld->sc_secsize;
        off_t disksize = ld->sc_secsize * ld->sc_secperunit;
        int error;

        tt->tt_sc = sc;
        tt->tt_bp = bp;

        memset(&tt->tt_aio, 0, sizeof(tt->tt_aio));
        tt->tt_aio.aio_fildes = sc->sc_fd;
        tt->tt_aio.aio_buf = bp->b_data;
        tt->tt_aio.aio_nbytes = bp->b_bcount;
        tt->tt_aio.aio_offset = offset;

        tt->tt_aio.aio_sigevent.sigev_notify = SIGEV_SIGNAL;
        tt->tt_aio.aio_sigevent.sigev_signo = SIGIO;
        tt->tt_aio.aio_sigevent.sigev_value.sival_ptr = tt;
#if 0
        device_printf(sc->sc_ld.sc_dv, "%s addr %p, off=%lld, count=%lld\n",
            (bp->b_flags & B_READ) ? "rd" : "wr",
            bp->b_data,
            (long long)bp->b_rawblkno,
            (long long)bp->b_bcount);
#endif
        if (sc->busy)
                panic("%s: reentry", __func__);

        if ((offset < 0) || (offset + bp->b_bcount > disksize)) {
                error = EIO;
                bp->b_error = error;
                bp->b_resid = bp->b_bcount;
        } else {
                sc->busy = true;
                if (bp->b_flags & B_READ)
                        error = thunk_aio_read(&tt->tt_aio);
                else
                        error = thunk_aio_write(&tt->tt_aio);
        }
        return error;
}

static void
ld_thunkbus_complete(void *arg)
{
        struct ld_softc *ld = arg;
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;
        struct ld_thunkbus_transfer *tt = &sc->sc_tt;
        struct buf *bp = tt->tt_bp;
        int error;

        /*
         * check if our aio has finished, we could be called for whatever
         * reason, for whatever SIGIO since signals can be missed.
         */
        if (!sc->busy)
                return;

        /* check if it was OUR sigio */
        error = thunk_aio_error(&tt->tt_aio);
        if (error == EINPROGRESS)
                return;

        /* use the result */
        if ((error == 0) &&
            thunk_aio_return(&tt->tt_aio) != -1) {
                bp->b_resid = 0;
        } else {
                bp->b_error = error;
                bp->b_resid = bp->b_bcount;
        }

        thunk_printf_debug("\tfin\n");
        if (bp->b_error)
                thunk_printf_debug("error!\n");

        sc->busy = false;
        lddone(&sc->sc_ld, bp);
}


#else /* LD_USE_AIO */


static int
ld_thunkbus_ldstart(struct ld_softc *ld, struct buf *bp)
{
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;
        struct ld_thunkbus_transfer *tt = &sc->sc_tt;

        tt->tt_sc = sc;
        tt->tt_bp = bp;

        /* let the softint do the work */
        sc->busy = true;
        softint_schedule(sc->sc_ih);

        return 0;
}

static void
ld_thunkbus_complete(void *arg)
{
        struct ld_softc *ld = arg;
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;
        struct ld_thunkbus_transfer *tt = &sc->sc_tt;
        struct buf *bp = tt->tt_bp;
        off_t offset = (off_t) bp->b_rawblkno * ld->sc_secsize;
        int64_t ret;

        if (!sc->busy)
                panic("%s: but not busy?\n", __func__);

        //printf("%s: %s %u @ %lld -> %p (flags 0x%08x)\n", __func__, 
        //    bp->b_flags & B_READ ? "read" : "write",
        //    (unsigned int)bp->b_bcount, (long long)offset, bp->b_data, bp->b_flags);

        /* this is silly, but better make sure */
        thunk_assert_presence((vaddr_t) bp->b_data, (size_t) bp->b_bcount);

        /* read/write the request */
        if (bp->b_flags & B_READ) {
                ret = thunk_pread(sc->sc_fd, bp->b_data, bp->b_bcount, offset);
        } else {
                ret = thunk_pwrite(sc->sc_fd, bp->b_data, bp->b_bcount, offset);
        }

        //if (ret == -1)
        //      printf("%s: errno = %d\n", __func__, thunk_geterrno());

        /* setup return params */
        if ((ret >= 0) && (ret == bp->b_bcount)) {
                bp->b_resid = 0;
        } else {
                // printf("ret = %d, errno %d?\n",(int) ret, thunk_geterrno());
                bp->b_error = thunk_geterrno();
                bp->b_resid = bp->b_bcount;
        }
        thunk_printf_debug("\tfin\n");
        if (bp->b_error)
                thunk_printf_debug("error!\n");

        sc->busy = false;
        lddone(&sc->sc_ld, bp);
}

#endif /* LD_USE_AIO */


static int
ld_thunkbus_lddump(struct ld_softc *ld, void *data, daddr_t blkno, int blkcnt)
{
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;
        ssize_t len;

        len = thunk_pwrite(sc->sc_fd, data, blkcnt, blkno * ld->sc_secsize);
        if (len == -1)
                return thunk_geterrno();
        else if (len != blkcnt) {
                device_printf(ld->sc_dv, "%s failed (short xfer)\n", __func__);
                return EIO;
        }

        return 0;
}


static int
ld_thunkbus_ioctl(struct ld_softc *ld, u_long cmd, void *addr, int32_t flag,
    bool poll)
{
        struct ld_thunkbus_softc *sc = (struct ld_thunkbus_softc *)ld;

        switch (cmd) {
        case DIOCCACHESYNC:
                if (thunk_fsync(sc->sc_fd) == -1)
                        return thunk_geterrno();
                return 0;
        default:
                return EPASSTHROUGH;
        }
}