/*      $NetBSD: ld.c,v 1.118 2025/10/04 09:38:06 skrll Exp $   */

/*-
 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Andrew Doran and Charles M. Hannum.
 *
 * 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.
 */

/*
 * Disk driver for use by RAID controllers.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ld.c,v 1.118 2025/10/04 09:38:06 skrll Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/queue.h>
#include <sys/proc.h>
#include <sys/buf.h>
#include <sys/bufq.h>
#include <sys/endian.h>
#include <sys/disklabel.h>
#include <sys/disk.h>
#include <sys/dkio.h>
#include <sys/stat.h>
#include <sys/conf.h>
#include <sys/fcntl.h>
#include <sys/vnode.h>
#include <sys/syslog.h>
#include <sys/mutex.h>
#include <sys/module.h>
#include <sys/reboot.h>

#include <dev/ldvar.h>

#include "ioconf.h"

static void     ldminphys(struct buf *bp);
static bool     ld_suspend(device_t, const pmf_qual_t *);
static bool     ld_resume(device_t, const pmf_qual_t *);
static bool     ld_shutdown(device_t, int);
static int      ld_diskstart(device_t, struct buf *bp);
static void     ld_iosize(device_t, int *);
static int      ld_dumpblocks(device_t, void *, daddr_t, int);
static void     ld_fake_geometry(struct ld_softc *);
static void     ld_set_geometry(struct ld_softc *);
static void     ld_config_interrupts (device_t);
static int      ld_lastclose(device_t);
static int      ld_discard(device_t, off_t, off_t);
static int      ld_flush(device_t, bool);

static dev_type_open(ldopen);
static dev_type_close(ldclose);
static dev_type_read(ldread);
static dev_type_write(ldwrite);
static dev_type_ioctl(ldioctl);
static dev_type_strategy(ldstrategy);
static dev_type_dump(lddump);
static dev_type_size(ldsize);
static dev_type_discard(lddiscard);

const struct bdevsw ld_bdevsw = {
        .d_open = ldopen,
        .d_close = ldclose,
        .d_strategy = ldstrategy,
        .d_ioctl = ldioctl,
        .d_dump = lddump,
        .d_psize = ldsize,
        .d_discard = lddiscard,
        .d_flag = D_DISK | D_MPSAFE
};

const struct cdevsw ld_cdevsw = {
        .d_open = ldopen,
        .d_close = ldclose,
        .d_read = ldread,
        .d_write = ldwrite,
        .d_ioctl = ldioctl,
        .d_stop = nostop,
        .d_tty = notty,
        .d_poll = nopoll,
        .d_mmap = nommap,
        .d_kqfilter = nokqfilter,
        .d_discard = lddiscard,
        .d_flag = D_DISK | D_MPSAFE
};

static const struct     dkdriver lddkdriver = {
        .d_open = ldopen,
        .d_close = ldclose,
        .d_strategy = ldstrategy,
        .d_iosize = ld_iosize,
        .d_minphys  = ldminphys,
        .d_diskstart = ld_diskstart,
        .d_dumpblocks = ld_dumpblocks,
        .d_lastclose = ld_lastclose,
        .d_discard = ld_discard
};

void
ldattach(struct ld_softc *sc, const char *default_strategy)
{
        device_t self = sc->sc_dv;
        struct dk_softc *dksc = &sc->sc_dksc;

        mutex_init(&sc->sc_mutex, MUTEX_DEFAULT, IPL_VM);
        cv_init(&sc->sc_drain, "lddrain");

        if ((sc->sc_flags & LDF_ENABLED) == 0) {
                return;
        }

        /* don't attach a disk that we cannot handle */
        if (sc->sc_secsize < DEV_BSIZE) {
                sc->sc_flags &= ~LDF_ENABLED;
                return;
        }

        /* Initialise dk and disk structure. */
        dk_init(dksc, self, DKTYPE_LD);
        disk_init(&dksc->sc_dkdev, dksc->sc_xname, &lddkdriver);

        if (sc->sc_maxxfer > MAXPHYS)
                sc->sc_maxxfer = MAXPHYS;

        /* Build synthetic geometry if necessary. */
        if (sc->sc_nheads == 0 || sc->sc_nsectors == 0 ||
            sc->sc_ncylinders == 0)
            ld_fake_geometry(sc);

        sc->sc_disksize512 = sc->sc_secperunit * sc->sc_secsize / DEV_BSIZE;

        if (sc->sc_flags & LDF_NO_RND)
                dksc->sc_flags |= DKF_NO_RND;

        /* Attach dk and disk subsystems */
        dk_attach(dksc);
        disk_attach(&dksc->sc_dkdev);
        ld_set_geometry(sc);

        bufq_alloc(&dksc->sc_bufq, default_strategy, BUFQ_SORT_RAWBLOCK);

        /* Register with PMF */
        if (!pmf_device_register1(dksc->sc_dev, ld_suspend, ld_resume,
                ld_shutdown))
                aprint_error_dev(dksc->sc_dev,
                    "couldn't establish power handler\n");

        /* Discover wedges on this disk. */
        config_interrupts(sc->sc_dv, ld_config_interrupts);
}

int
ldadjqparam(struct ld_softc *sc, int xmax)
{

        mutex_enter(&sc->sc_mutex);
        sc->sc_maxqueuecnt = xmax;
        mutex_exit(&sc->sc_mutex);

        return (0);
}

int
ldbegindetach(struct ld_softc *sc, int flags)
{
        struct dk_softc *dksc = &sc->sc_dksc;
        int error;

        /* If we never attached properly, no problem with detaching.  */
        if ((sc->sc_flags & LDF_ENABLED) == 0)
                return 0;

        /*
         * If the disk is still open, back out before we commit to
         * detaching.
         */
        error = disk_begindetach(&dksc->sc_dkdev, ld_lastclose, dksc->sc_dev,
            flags);
        if (error)
                return error;

        /* We are now committed to detaching.  Prevent new xfers.  */
        ldadjqparam(sc, 0);

        return 0;
}

void
ldenddetach(struct ld_softc *sc)
{
        struct dk_softc *dksc = &sc->sc_dksc;
        int bmaj, cmaj, i, mn;

        if ((sc->sc_flags & LDF_ENABLED) == 0)
                return;

        /* Wait for commands queued with the hardware to complete. */
        mutex_enter(&sc->sc_mutex);
        while (sc->sc_queuecnt > 0) {
                if (cv_timedwait(&sc->sc_drain, &sc->sc_mutex, 30 * hz)) {
                        /*
                         * XXX This seems like a recipe for crashing on
                         * use after free...
                         */
                        printf("%s: not drained\n", dksc->sc_xname);
                        break;
                }
        }
        mutex_exit(&sc->sc_mutex);

        /* Kill off any queued buffers. */
        dk_drain(dksc);
        bufq_free(dksc->sc_bufq);

        /* Locate the major numbers. */
        bmaj = bdevsw_lookup_major(&ld_bdevsw);
        cmaj = cdevsw_lookup_major(&ld_cdevsw);

        /* Nuke the vnodes for any open instances. */
        for (i = 0; i < MAXPARTITIONS; i++) {
                mn = DISKMINOR(device_unit(dksc->sc_dev), i);
                vdevgone(bmaj, mn, mn, VBLK);
                vdevgone(cmaj, mn, mn, VCHR);
        }

        /* Delete all of our wedges. */
        dkwedge_delall(&dksc->sc_dkdev);

        /* Detach from the disk list. */
        disk_detach(&dksc->sc_dkdev);
        disk_destroy(&dksc->sc_dkdev);

        dk_detach(dksc);

        /* Deregister with PMF */
        pmf_device_deregister(dksc->sc_dev);

        /*
         * XXX We can't really flush the cache here, because the
         * XXX device may already be non-existent from the controller's
         * XXX perspective.
         */
#if 0
        ld_flush(dksc->sc_dev, false);
#endif
        cv_destroy(&sc->sc_drain);
        mutex_destroy(&sc->sc_mutex);
}

/* ARGSUSED */
static bool
ld_suspend(device_t dev, const pmf_qual_t *qual)
{
        struct ld_softc *sc = device_private(dev);
        int queuecnt;
        bool ok = false;

        /* Block new requests and wait for outstanding requests to drain.  */
        mutex_enter(&sc->sc_mutex);
        KASSERT((sc->sc_flags & LDF_SUSPEND) == 0);
        sc->sc_flags |= LDF_SUSPEND;
        while ((queuecnt = sc->sc_queuecnt) > 0) {
                if (cv_timedwait(&sc->sc_drain, &sc->sc_mutex, 30 * hz))
                        break;
        }
        mutex_exit(&sc->sc_mutex);

        /* Block suspend if we couldn't drain everything in 30sec.  */
        if (queuecnt > 0) {
                device_printf(dev, "timeout draining buffers\n");
                goto out;
        }

        /* Flush cache before we lose power.  If we can't, block suspend.  */
        if (ld_flush(dev, /*poll*/false) != 0) {
                device_printf(dev, "failed to flush cache\n");
                goto out;
        }

        /* Success!  */
        ok = true;

out:    if (!ok)
                (void)ld_resume(dev, qual);
        return ok;
}

static bool
ld_resume(device_t dev, const pmf_qual_t *qual)
{
        struct ld_softc *sc = device_private(dev);

        /* Allow new requests to come in.  */
        mutex_enter(&sc->sc_mutex);
        KASSERT(sc->sc_flags & LDF_SUSPEND);
        sc->sc_flags &= ~LDF_SUSPEND;
        mutex_exit(&sc->sc_mutex);

        /* Restart any pending queued requests.  */
        dk_start(&sc->sc_dksc, NULL);

        return true;
}

/* ARGSUSED */
static bool
ld_shutdown(device_t dev, int flags)
{
        if ((flags & RB_NOSYNC) == 0 && ld_flush(dev, true) != 0)
                return false;

        return true;
}

/* ARGSUSED */
static int
ldopen(dev_t dev, int flags, int fmt, struct lwp *l)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit;

        unit = DISKUNIT(dev);
        if ((sc = device_lookup_private(&ld_cd, unit)) == NULL)
                return (ENXIO);

        if ((sc->sc_flags & LDF_ENABLED) == 0)
                return (ENODEV);

        dksc = &sc->sc_dksc;

        return dk_open(dksc, dev, flags, fmt, l);
}

static int
ld_lastclose(device_t self)
{
        ld_flush(self, false);

        return 0;
}

/* ARGSUSED */
static int
ldclose(dev_t dev, int flags, int fmt, struct lwp *l)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit;

        unit = DISKUNIT(dev);
        sc = device_lookup_private(&ld_cd, unit);
        dksc = &sc->sc_dksc;

        return dk_close(dksc, dev, flags, fmt, l);
}

/* ARGSUSED */
static int
ldread(dev_t dev, struct uio *uio, int ioflag)
{

        return (physio(ldstrategy, NULL, dev, B_READ, ldminphys, uio));
}

/* ARGSUSED */
static int
ldwrite(dev_t dev, struct uio *uio, int ioflag)
{

        return (physio(ldstrategy, NULL, dev, B_WRITE, ldminphys, uio));
}

/* ARGSUSED */
static int
ldioctl(dev_t dev, u_long cmd, void *addr, int32_t flag, struct lwp *l)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit, error;

        unit = DISKUNIT(dev);
        sc = device_lookup_private(&ld_cd, unit);
        dksc = &sc->sc_dksc;

        error = 0;

        /*
         * Some common checks so that individual attachments wouldn't need
         * to duplicate them.
         */
        switch (cmd) {
        case DIOCCACHESYNC:
                /*
                 * XXX Do we really need to care about having a writable
                 * file descriptor here?
                 */
                if ((flag & FWRITE) == 0)
                        error = EBADF;
                else
                        error = 0;
                break;
        }

        if (error != 0)
                return (error);

        if (sc->sc_ioctl) {
                if ((sc->sc_flags & LDF_MPSAFE) == 0)
                        KERNEL_LOCK(1, curlwp);
                error = (*sc->sc_ioctl)(sc, cmd, addr, flag, 0);
                if ((sc->sc_flags & LDF_MPSAFE) == 0)
                        KERNEL_UNLOCK_ONE(curlwp);
                if (error != EPASSTHROUGH)
                        return (error);
        }

        /* something not handled by the attachment */
        return dk_ioctl(dksc, dev, cmd, addr, flag, l);
}

/*
 * Flush the device's cache.
 */
static int
ld_flush(device_t self, bool poll)
{
        int error = 0;
        struct ld_softc *sc = device_private(self);

        if (sc->sc_ioctl) {
                if ((sc->sc_flags & LDF_MPSAFE) == 0)
                        KERNEL_LOCK(1, curlwp);
                error = (*sc->sc_ioctl)(sc, DIOCCACHESYNC, NULL, 0, poll);
                if ((sc->sc_flags & LDF_MPSAFE) == 0)
                        KERNEL_UNLOCK_ONE(curlwp);
                if (error != 0)
                        device_printf(self, "unable to flush cache\n");
        }

        return error;
}

static void
ldstrategy(struct buf *bp)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit;

        unit = DISKUNIT(bp->b_dev);
        sc = device_lookup_private(&ld_cd, unit);
        dksc = &sc->sc_dksc;

        dk_strategy(dksc, bp);
}

static int
ld_diskstart(device_t dev, struct buf *bp)
{
        struct ld_softc *sc = device_private(dev);
        int error;

        if (sc->sc_queuecnt >= sc->sc_maxqueuecnt ||
            sc->sc_flags & LDF_SUSPEND) {
                if (sc->sc_flags & LDF_SUSPEND)
                        aprint_debug_dev(dev, "i/o blocked while suspended\n");
                return EAGAIN;
        }

        if ((sc->sc_flags & LDF_MPSAFE) == 0)
                KERNEL_LOCK(1, curlwp);

        mutex_enter(&sc->sc_mutex);

        if (sc->sc_queuecnt >= sc->sc_maxqueuecnt ||
            sc->sc_flags & LDF_SUSPEND) {
                if (sc->sc_flags & LDF_SUSPEND)
                        aprint_debug_dev(dev, "i/o blocked while suspended\n");
                error = EAGAIN;
        } else {
                error = (*sc->sc_start)(sc, bp);
                if (error == 0)
                        sc->sc_queuecnt++;
        }

        mutex_exit(&sc->sc_mutex);

        if ((sc->sc_flags & LDF_MPSAFE) == 0)
                KERNEL_UNLOCK_ONE(curlwp);

        return error;
}

void
lddone(struct ld_softc *sc, struct buf *bp)
{
        struct dk_softc *dksc = &sc->sc_dksc;

        dk_done(dksc, bp);

        mutex_enter(&sc->sc_mutex);
        if (--sc->sc_queuecnt <= sc->sc_maxqueuecnt) {
                cv_broadcast(&sc->sc_drain);
                mutex_exit(&sc->sc_mutex);
                dk_start(dksc, NULL);
        } else
                mutex_exit(&sc->sc_mutex);
}

static int
ldsize(dev_t dev)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit;

        unit = DISKUNIT(dev);
        if ((sc = device_lookup_private(&ld_cd, unit)) == NULL)
                return (-1);
        dksc = &sc->sc_dksc;

        if ((sc->sc_flags & LDF_ENABLED) == 0)
                return (-1);

        return dk_size(dksc, dev);
}

/*
 * Take a dump.
 */
static int
lddump(dev_t dev, daddr_t blkno, void *va, size_t size)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit;

        unit = DISKUNIT(dev);
        if ((sc = device_lookup_private(&ld_cd, unit)) == NULL)
                return (ENXIO);
        dksc = &sc->sc_dksc;

        if ((sc->sc_flags & LDF_ENABLED) == 0)
                return (ENODEV);

        return dk_dump(dksc, dev, blkno, va, size, 0);
}

static int
ld_dumpblocks(device_t dev, void *va, daddr_t blkno, int nblk)
{
        struct ld_softc *sc = device_private(dev);

        if (sc->sc_dump == NULL)
                return (ENODEV);

        /*
         * Minimum consistency check; sc_dump() should check
         * device-dependent constraints if necessary.
         */
        if (blkno < 0)
                return (EIO);

        return (*sc->sc_dump)(sc, va, blkno, nblk);
}

/*
 * Adjust the size of a transfer.
 */
static void
ldminphys(struct buf *bp)
{
        int unit;
        struct ld_softc *sc;

        unit = DISKUNIT(bp->b_dev);
        sc = device_lookup_private(&ld_cd, unit);

        ld_iosize(sc->sc_dv, &bp->b_bcount);
        minphys(bp);
}

static void
ld_iosize(device_t d, int *countp)
{
        struct ld_softc *sc = device_private(d);

        if (*countp > sc->sc_maxxfer)
                *countp = sc->sc_maxxfer;
}

static void
ld_fake_geometry(struct ld_softc *sc)
{
        uint64_t ncyl;

        if (sc->sc_secperunit <= 528 * 2048)            /* 528MB */
                sc->sc_nheads = 16;
        else if (sc->sc_secperunit <= 1024 * 2048)      /* 1GB */
                sc->sc_nheads = 32;
        else if (sc->sc_secperunit <= 21504 * 2048)     /* 21GB */
                sc->sc_nheads = 64;
        else if (sc->sc_secperunit <= 43008 * 2048)     /* 42GB */
                sc->sc_nheads = 128;
        else
                sc->sc_nheads = 255;

        sc->sc_nsectors = 63;
        sc->sc_ncylinders = INT_MAX;
        ncyl = sc->sc_secperunit /
            (sc->sc_nheads * sc->sc_nsectors);
        if (ncyl < INT_MAX)
                sc->sc_ncylinders = (int)ncyl;
}

static void
ld_set_geometry(struct ld_softc *sc)
{
        struct dk_softc *dksc = &sc->sc_dksc;
        struct disk_geom *dg = &dksc->sc_dkdev.dk_geom;
        char tbuf[9];

        format_bytes(tbuf, sizeof(tbuf), sc->sc_secperunit *
            sc->sc_secsize);
        aprint_normal_dev(dksc->sc_dev, "%s, %d cyl, %d head, %d sec, "
            "%d bytes/sect x %"PRIu64" sectors",
            tbuf, sc->sc_ncylinders, sc->sc_nheads,
            sc->sc_nsectors, sc->sc_secsize, sc->sc_secperunit);
        if (sc->sc_physsecsize != 0 && sc->sc_physsecsize != sc->sc_secsize) {
                aprint_normal(" (%d bytes/physsect", sc->sc_physsecsize);
                if (sc->sc_alignedsec != 0)
                        aprint_normal("; first aligned sector %u",
                            sc->sc_alignedsec);
                aprint_normal(")");
        }
        aprint_normal("\n");

        memset(dg, 0, sizeof(*dg));
        dg->dg_secperunit = sc->sc_secperunit;
        dg->dg_secsize = sc->sc_secsize;
        dg->dg_nsectors = sc->sc_nsectors;
        dg->dg_ntracks = sc->sc_nheads;
        dg->dg_ncylinders = sc->sc_ncylinders;
        dg->dg_physsecsize = sc->sc_physsecsize;
        dg->dg_alignedsec = sc->sc_alignedsec;

        disk_set_info(dksc->sc_dev, &dksc->sc_dkdev, sc->sc_typename);
}

static void
ld_config_interrupts(device_t d)
{
        struct ld_softc *sc = device_private(d);
        struct dk_softc *dksc = &sc->sc_dksc;

        dkwedge_discover(&dksc->sc_dkdev);
}

static int
ld_discard(device_t dev, off_t pos, off_t len)
{
        struct ld_softc *sc = device_private(dev);
        struct buf dbuf, *bp = &dbuf;
        int error = 0;

        KASSERT(len <= INT_MAX);

        if (sc->sc_discard == NULL)
                return (ENODEV);

        if ((sc->sc_flags & LDF_MPSAFE) == 0)
                KERNEL_LOCK(1, curlwp);

        buf_init(bp);
        bp->b_vp = NULL;
        bp->b_data = NULL;
        bp->b_bufsize = 0;
        bp->b_rawblkno = pos / sc->sc_secsize;
        bp->b_bcount = len;
        bp->b_flags = B_WRITE;
        bp->b_cflags = BC_BUSY;

        error = (*sc->sc_discard)(sc, bp);
        if (error == 0)
                error = biowait(bp);

        buf_destroy(bp);

        if ((sc->sc_flags & LDF_MPSAFE) == 0)
                KERNEL_UNLOCK_ONE(curlwp);

        return error;
}

void
lddiscardend(struct ld_softc *sc, struct buf *bp)
{

        if (bp->b_error)
                bp->b_resid = bp->b_bcount;
        biodone(bp);
}

static int
lddiscard(dev_t dev, off_t pos, off_t len)
{
        struct ld_softc *sc;
        struct dk_softc *dksc;
        int unit;

        unit = DISKUNIT(dev);
        sc = device_lookup_private(&ld_cd, unit);
        dksc = &sc->sc_dksc;

        return dk_discard(dksc, dev, pos, len);
}

MODULE(MODULE_CLASS_DRIVER, ld, "dk_subr");

#ifdef _MODULE
CFDRIVER_DECL(ld, DV_DISK, NULL);
#endif

static int
ld_modcmd(modcmd_t cmd, void *opaque)
{
#ifdef _MODULE
        devmajor_t bmajor, cmajor;
#endif
        int error = 0;

#ifdef _MODULE
        switch (cmd) {
        case MODULE_CMD_INIT:
                bmajor = cmajor = -1;
                error = devsw_attach(ld_cd.cd_name, &ld_bdevsw, &bmajor,
                    &ld_cdevsw, &cmajor);
                if (error)
                        break;
                error = config_cfdriver_attach(&ld_cd);
                break;
        case MODULE_CMD_FINI:
                error = config_cfdriver_detach(&ld_cd);
                if (error)
                        break;
                devsw_detach(&ld_bdevsw, &ld_cdevsw);
                break;
        default:
                error = ENOTTY;
                break;
        }
#endif

        return error;
}