/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 * Implementation of "scsi_vhci_f_tpgs_tape" T10 standard based failover_ops.
 *
 * NOTE: for sequential devices only.
 */

#include <sys/conf.h>
#include <sys/file.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>
#include <sys/scsi/scsi.h>
#include <sys/scsi/adapters/scsi_vhci.h>
#include <sys/scsi/adapters/scsi_vhci_tpgs.h>

/* Supported device table entries.  */
char *tpgs_tape_dev_table[] = { NULL };
static void tpgs_tape_init(void);
static int tpgs_tape_device_probe(struct scsi_device *sd,
    struct scsi_inquiry *inq, void **ctpriv);

/* Failover module plumbing. */
#ifdef  lint
#define scsi_vhci_failover_ops  scsi_vhci_failover_ops_f_tpgs_tape
#endif  /* lint */
struct scsi_failover_ops scsi_vhci_failover_ops = {
        SFO_REV,
        "f_tpgs_tape",
        tpgs_tape_dev_table,
        tpgs_tape_init,
        tpgs_tape_device_probe,
        /* The rest of the implementation comes from SFO_NAME_TPGS import  */
};

static struct modlmisc modlmisc = {
        &mod_miscops, "f_tpgs_tape"
};

static struct modlinkage modlinkage = {
        MODREV_1, (void *)&modlmisc, NULL
};



/*
 * External function definitions
 */
extern struct scsi_failover_ops *vhci_failover_ops_by_name(char *);

int
_init()
{
        return (mod_install(&modlinkage));
}

int
_fini()
{
        return (mod_remove(&modlinkage));
}

int
_info(struct modinfo *modinfop)
{
        return (mod_info(&modlinkage, modinfop));
}



/* ARGSUSED */
static int
tpgs_tape_device_probe(struct scsi_device *sd, struct scsi_inquiry *inq,
    void **ctpriv)
{
        int mode;
        int state;
        int xlf;
        int preferred = 0;
        int support;

        VHCI_DEBUG(6, (CE_NOTE, NULL, "tpgs_tape_device_probe: vidpid %s\n",
            inq->inq_vid));

        if (inq->inq_tpgs == TPGS_FAILOVER_NONE) {
                VHCI_DEBUG(4, (CE_WARN, NULL,
                    "!tpgs_tape_device_probe: not a standard tpgs device"));
                support = SFO_DEVICE_PROBE_PHCI;
        } else if (inq->inq_dtype != DTYPE_SEQUENTIAL) {
                VHCI_DEBUG(4, (CE_NOTE, NULL,
                    "!tpgs_tape_device_probe: Detected a "
                    "Standard Asymmetric device "
                    "not yet supported\n"));
                support = SFO_DEVICE_PROBE_PHCI;
        } else if (vhci_tpgs_get_target_fo_mode(sd, &mode, &state, &xlf,
            &preferred)) {
                VHCI_DEBUG(4, (CE_WARN, NULL, "!unable to fetch fo "
                    "mode: sd(%p)", (void *) sd));
                support = SFO_DEVICE_PROBE_PHCI;
        } else if (inq->inq_tpgs == TPGS_FAILOVER_IMPLICIT) {
                VHCI_DEBUG(1, (CE_NOTE, NULL,
                    "!tpgs_tape_device_probe: Detected a "
                    "Standard Asymmetric device "
                    "with implicit failover\n"));
                support = SFO_DEVICE_PROBE_VHCI;
        } else if (inq->inq_tpgs == TPGS_FAILOVER_EXPLICIT) {
                VHCI_DEBUG(1, (CE_NOTE, NULL,
                    "!tpgs_tape_device_probe: Detected a "
                    "Standard Asymmetric device "
                    "with explicit failover\n"));
                support = SFO_DEVICE_PROBE_VHCI;
        } else if (inq->inq_tpgs == TPGS_FAILOVER_BOTH) {
                VHCI_DEBUG(1, (CE_NOTE, NULL,
                    "!tpgs_tape_device_probe: Detected a "
                    "Standard Asymmetric device "
                    "which supports both implicit and explicit failover\n"));
                support = SFO_DEVICE_PROBE_VHCI;
        } else {
                VHCI_DEBUG(1, (CE_WARN, NULL,
                    "!tpgs_tape_device_probe: "
                    "Unknown tpgs_bits: %x", inq->inq_tpgs));
                support = SFO_DEVICE_PROBE_PHCI;
        }

        if (support == SFO_DEVICE_PROBE_VHCI) {
                /*
                 * Policy only applies to 'client' probe, not
                 * vhci_is_dev_supported() pHCI probe. Detect difference
                 * based on ctpriv.
                 */
                if (ctpriv &&
                    (mdi_set_lb_policy(sd->sd_dev, LOAD_BALANCE_NONE) !=
                    MDI_SUCCESS)) {
                        VHCI_DEBUG(6, (CE_NOTE, NULL, "!fail load balance none"
                            ": %s\n", inq->inq_vid));
                        support = SFO_DEVICE_PROBE_PHCI;
                }
        }
        return (support);
}

static void
tpgs_tape_init(void)
{
        struct scsi_failover_ops        *sfo, *ssfo, clone;

        /* clone SFO_NAME_SYM implementation for most things */
        ssfo = vhci_failover_ops_by_name(SFO_NAME_TPGS);
        if (ssfo == NULL) {
                VHCI_DEBUG(4, (CE_NOTE, NULL, "!tpgs_tape: "
                    "can't import " SFO_NAME_SYM "\n"));
                return;
        }
        sfo                     = &scsi_vhci_failover_ops;
        clone                   = *ssfo;
        clone.sfo_rev           = sfo->sfo_rev;
        clone.sfo_name          = sfo->sfo_name;
        clone.sfo_devices       = sfo->sfo_devices;
        clone.sfo_init          = sfo->sfo_init;
        clone.sfo_device_probe  = sfo->sfo_device_probe;
        *sfo                    = clone;
}