common/io/pseudonex.c

	pseudonex.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2005 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

/*
 * Pseudo devices are devices implemented entirely in software; pseudonex
 * (pseudo) is the traditional nexus for pseudodevices.  Instances are
 * typically specified via driver.conf files; e.g. a leaf device which
 * should be attached below pseudonex will have an entry like:
 *
 *  name="foo" parent="/pseudo" instance=0;
 *
 * pseudonex also supports the devctl (see <sys/devctl.h>) interface via
 * its :devctl minor node.  This allows priveleged userland applications to
 * online/offline children of pseudo as needed.
 *
 * In general, we discourage widespread use of this tactic, as it may lead to a
 * proliferation of nodes in /pseudo.  It is preferred that implementors update
 * pseudo.conf, adding another 'pseudo' nexus child of /pseudo, and then use
 * that for their collection of device nodes.  To do so, add a driver alias
 * for the name of the nexus child and a line in pseudo.conf such as:
 *
 *  name="foo" parent="/pseudo" instance=<n> valid-children="bar","baz";
 *
 * Setting 'valid-children' is important because we have an annoying problem;
 * we need to prevent pseudo devices with 'parent="pseudo"' set from binding
 * to our new pseudonex child node.  A better way might be to teach the
 * spec-node code to understand that parent="pseudo" really means
 * parent="/pseudo".
 *
 * At some point in the future, it would be desirable to extend the instance
 * database to include nexus children of pseudo.  Then we could use devctl
 * or devfs to online nexus children of pseudo, auto-selecting an instance #,
 * and the instance number selected would be preserved across reboot in
 * path_to_inst.
 */

#include <sys/types.h>
#include <sys/cmn_err.h>
#include <sys/conf.h>
#include <sys/ddi.h>
#include <sys/ddi_impldefs.h>
#include <sys/devops.h>
#include <sys/instance.h>
#include <sys/modctl.h>
#include <sys/open.h>
#include <sys/stat.h>
#include <sys/sunddi.h>
#include <sys/sunndi.h>
#include <sys/systm.h>
#include <sys/mkdev.h>

/*
 * Config information
 */
static int pseudonex_intr_op(dev_info_t *dip, dev_info_t *rdip,
        ddi_intr_op_t op, ddi_intr_handle_impl_t *hdlp, void *result);

static int pseudonex_attach(dev_info_t *, ddi_attach_cmd_t);
static int pseudonex_detach(dev_info_t *, ddi_detach_cmd_t);
static int pseudonex_open(dev_t *, int, int, cred_t *);
static int pseudonex_close(dev_t, int, int, cred_t *);
static int pseudonex_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);
static int pseudonex_ctl(dev_info_t *, dev_info_t *, ddi_ctl_enum_t, void *,
    void *);

static void *pseudonex_state;

typedef struct pseudonex_state {
    dev_info_t *pnx_devi;
} pseudonex_state_t;

static struct bus_ops pseudonex_bus_ops = {
    BUSO_REV,
    nullbusmap,     /* bus_map */
    NULL,           /* bus_get_intrspec */
    NULL,           /* bus_add_intrspec */
    NULL,           /* bus_remove_intrspec */
    i_ddi_map_fault,    /* bus_map_fault */
    ddi_no_dma_map,     /* bus_dma_map */
    ddi_no_dma_allochdl,    /* bus_dma_allochdl */
    NULL,           /* bus_dma_freehdl */
    NULL,           /* bus_dma_bindhdl */
    NULL,           /* bus_dma_unbindhdl */
    NULL,           /* bus_dma_flush */
    NULL,           /* bus_dma_win */
    NULL,           /* bus_dma_ctl */
    pseudonex_ctl,      /* bus_ctl */
    ddi_bus_prop_op,    /* bus_prop_op */
    0,          /* bus_get_eventcookie */
    0,          /* bus_add_eventcall */
    0,          /* bus_remove_eventcall */
    0,          /* bus_post_event */
    NULL,           /* bus_intr_ctl */
    NULL,           /* bus_config */
    NULL,           /* bus_unconfig */
    NULL,           /* bus_fm_init */
    NULL,           /* bus_fm_fini */
    NULL,           /* bus_fm_access_enter */
    NULL,           /* bus_fm_access_exit */
    NULL,           /* bus_power */
    pseudonex_intr_op   /* bus_intr_op */
};

static struct cb_ops pseudonex_cb_ops = {
    pseudonex_open,         /* open */
    pseudonex_close,        /* close */
    nodev,              /* strategy */
    nodev,              /* print */
    nodev,              /* dump */
    nodev,              /* read */
    nodev,              /* write */
    pseudonex_ioctl,        /* ioctl */
    nodev,              /* devmap */
    nodev,              /* mmap */
    nodev,              /* segmap */
    nochpoll,           /* poll */
    ddi_prop_op,            /* cb_prop_op */
    0,              /* streamtab  */
    D_MP | D_NEW | D_HOTPLUG    /* Driver compatibility flag */
};

static struct dev_ops pseudo_ops = {
    DEVO_REV,       /* devo_rev, */
    0,          /* refcnt  */
    ddi_getinfo_1to1,   /* info */
    nulldev,        /* identify */
    nulldev,        /* probe */
    pseudonex_attach,   /* attach */
    pseudonex_detach,   /* detach */
    nodev,          /* reset */
    &pseudonex_cb_ops,  /* driver operations */
    &pseudonex_bus_ops, /* bus operations */
    nulldev         /* power */
};

/*
 * Module linkage information for the kernel.
 */
static struct modldrv modldrv = {
    &mod_driverops,
    "nexus driver for 'pseudo' %I%",
    &pseudo_ops,
};

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

int
_init(void)
{
    int err;

    if ((err = ddi_soft_state_init(&pseudonex_state,
        sizeof (pseudonex_state_t), 0)) != 0) {
        return (err);
    }
    if ((err = mod_install(&modlinkage)) != 0) {
        ddi_soft_state_fini(&pseudonex_state);
        return (err);
    }
    return (0);
}

int
_fini(void)
{
    int err;

    if ((err = mod_remove(&modlinkage)) != 0)
        return (err);
    ddi_soft_state_fini(&pseudonex_state);
    return (0);
}

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

/*ARGSUSED*/
static int
pseudonex_attach(dev_info_t *devi, ddi_attach_cmd_t cmd)
{
    int instance;
    pseudonex_state_t *pnx_state;

    switch (cmd) {
    case DDI_ATTACH:
        break;
    case DDI_RESUME:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }

    /*
     * Save the devi for this instance in the soft_state data.
     */
    instance = ddi_get_instance(devi);
    if (ddi_soft_state_zalloc(pseudonex_state, instance) != DDI_SUCCESS)
        return (DDI_FAILURE);
    pnx_state = ddi_get_soft_state(pseudonex_state, instance);
    pnx_state->pnx_devi = devi;

    if (ddi_create_minor_node(devi, "devctl", S_IFCHR, instance,
        DDI_NT_NEXUS, 0) != DDI_SUCCESS) {
        ddi_remove_minor_node(devi, NULL);
        ddi_soft_state_free(pseudonex_state, instance);
        return (DDI_FAILURE);
    }
    ddi_report_dev(devi);
    return (DDI_SUCCESS);
}

/*ARGSUSED*/
static int
pseudonex_detach(dev_info_t *devi, ddi_detach_cmd_t cmd)
{
    int instance = ddi_get_instance(devi);

    if (cmd == DDI_SUSPEND)
        return (DDI_SUCCESS);

    ddi_remove_minor_node(devi, NULL);
    ddi_soft_state_free(pseudonex_state, instance);
    return (DDI_SUCCESS);
}

/*ARGSUSED*/
static int
pseudonex_open(dev_t *devp, int flags, int otyp, cred_t *credp)
{
    int instance;

    if (otyp != OTYP_CHR)
        return (EINVAL);

    instance = getminor(*devp);
    if (ddi_get_soft_state(pseudonex_state, instance) == NULL)
        return (ENXIO);

    return (0);
}

/*ARGSUSED*/
static int
pseudonex_close(dev_t dev, int flags, int otyp, cred_t *credp)
{
    int instance;

    if (otyp != OTYP_CHR)
        return (EINVAL);

    instance = getminor(dev);
    if (ddi_get_soft_state(pseudonex_state, instance) == NULL)
        return (ENXIO);

    return (0);
}

/*ARGSUSED*/
static int
pseudonex_ioctl(dev_t dev,
    int cmd, intptr_t arg, int mode, cred_t *cred_p, int *rval_p)
{
    int instance;
    pseudonex_state_t *pnx_state;

    instance = getminor(dev);
    if ((pnx_state = ddi_get_soft_state(pseudonex_state, instance)) == NULL)
        return (ENXIO);
    ASSERT(pnx_state->pnx_devi);
    return (ndi_devctl_ioctl(pnx_state->pnx_devi, cmd, arg, mode, 0));
}

/*
 * pseudonex_intr_op: pseudonex convert an interrupt number to an
 *          interrupt. NO OP for pseudo drivers.
 */
/*ARGSUSED*/
static int
pseudonex_intr_op(dev_info_t *dip, dev_info_t *rdip, ddi_intr_op_t op,
    ddi_intr_handle_impl_t *hdlp, void *result)
{
    return (DDI_FAILURE);
}

static int
pseudonex_check_assignment(dev_info_t *child, int test_inst)
{
    dev_info_t  *tdip;
    kmutex_t    *dmp;
    const char  *childname = ddi_driver_name(child);
    major_t     childmaj = ddi_name_to_major((char *)childname);

    dmp = &devnamesp[childmaj].dn_lock;
    LOCK_DEV_OPS(dmp);
    for (tdip = devnamesp[childmaj].dn_head;
        tdip != NULL; tdip = ddi_get_next(tdip)) {
        /* is this the current node? */
        if (tdip == child)
            continue;
        /* is this a duplicate instance? */
        if (test_inst == ddi_get_instance(tdip)) {
            UNLOCK_DEV_OPS(dmp);
            return (DDI_FAILURE);
        }
    }
    UNLOCK_DEV_OPS(dmp);
    return (DDI_SUCCESS);
}

/*
 * This is a nasty, slow hack.  But we're stuck with it until we do some
 * major surgery on the instance assignment subsystem, to allow pseudonode
 * instance assignment to be tracked there.
 *
 * To auto-assign an instance number, we exhaustively search the instance
 * list for each possible instance number until we find one which is unused.
 */
static int
pseudonex_auto_assign(dev_info_t *child)
{
    dev_info_t  *tdip;
    kmutex_t    *dmp;
    const char  *childname = ddi_driver_name(child);
    major_t     childmaj = ddi_name_to_major((char *)childname);
    int inst = 0;

    dmp = &devnamesp[childmaj].dn_lock;
    LOCK_DEV_OPS(dmp);
    for (inst = 0; inst <= MAXMIN32; inst++) {
        for (tdip = devnamesp[childmaj].dn_head; tdip != NULL;
            tdip = ddi_get_next(tdip)) {
            /* is this the current node? */
            if (tdip == child)
                continue;
            if (inst == ddi_get_instance(tdip)) {
                break;
            }
        }
        if (tdip == NULL) {
            UNLOCK_DEV_OPS(dmp);
            return (inst);
        }
    }
    UNLOCK_DEV_OPS(dmp);
    return (-1);
}

static int
pseudonex_ctl(dev_info_t *dip, dev_info_t *rdip, ddi_ctl_enum_t ctlop,
    void *arg, void *result)
{
    switch (ctlop) {
    case DDI_CTLOPS_REPORTDEV:
        if (rdip == NULL)
            return (DDI_FAILURE);
        cmn_err(CE_CONT, "?pseudo-device: %s%d\n",
            ddi_driver_name(rdip), ddi_get_instance(rdip));
        return (DDI_SUCCESS);

    case DDI_CTLOPS_INITCHILD:
    {
        char name[12];  /* enough for a decimal integer */
        int instance = -1;
        dev_info_t *child = (dev_info_t *)arg;
        const char *childname = ddi_driver_name(child);
        char **childlist;
        uint_t nelems;
        int auto_assign = 0;

        /*
         * If this pseudonex node has a valid-children property,
         * then that acts as an access control list for children
         * allowed to attach beneath this node.  Honor it.
         */
        if (ddi_prop_lookup_string_array(DDI_DEV_T_ANY, dip,
            DDI_PROP_DONTPASS, "valid-children", &childlist,
            &nelems) == DDI_PROP_SUCCESS) {
            int i, ok = 0;
            for (i = 0; i < nelems; i++) {
                if (strcmp(childlist[i], childname) == 0) {
                    ok = 1;
                    break;
                }
            }
            ddi_prop_free(childlist);
            if (!ok)
                return (DDI_FAILURE);
        }

        /*
         * Look up the "instance" property. If it does not exist,
         * check to see if the "auto-assign-instance" property is set.
         * If not, default to using instance 0; while not ideal, this
         * is a legacy behavior we must continue to support.
         */
        instance = ddi_prop_get_int(DDI_DEV_T_ANY, child,
            DDI_PROP_DONTPASS, "instance", -1);
        auto_assign = ddi_prop_exists(DDI_DEV_T_ANY, child,
            DDI_PROP_DONTPASS, "auto-assign-instance");
        NDI_CONFIG_DEBUG((CE_NOTE,
            "pseudonex: DDI_CTLOPS_INITCHILD(instance=%d, "
            "auto-assign=%d)", instance, auto_assign));

        if (instance != -1 && auto_assign != 0) {
            NDI_CONFIG_DEBUG((CE_NOTE, "both instance and "
                "auto-assign-instance properties specified. "
                "Node rejected."));
            return (DDI_FAILURE);
        }

        if (instance == -1 && auto_assign == 0) {
            /* default to instance 0 if not specified */
            NDI_CONFIG_DEBUG((CE_NOTE, "defaulting to 0"));
            instance = 0;
        }

        /*
         * If an instance has been specified, determine if this
         * instance is already in use; if we need to pick an instance,
         * we do it here.
         */
        if (auto_assign) {
            if ((instance = pseudonex_auto_assign(child)) == -1) {
                NDI_CONFIG_DEBUG((CE_NOTE, "failed to "
                    "auto-select instance for %s", childname));
                return (DDI_FAILURE);
            }
            NDI_CONFIG_DEBUG((CE_NOTE,
                "auto-selected instance for %s: %d",
                childname, instance));
        } else {
            if (pseudonex_check_assignment(child, instance) ==
                DDI_FAILURE) {
                NDI_CONFIG_DEBUG((CE_WARN,
                    "Duplicate instance %d of node \"%s\" "
                    "ignored.", instance, childname));
                return (DDI_FAILURE);
            }
            NDI_CONFIG_DEBUG((CE_NOTE,
                "using fixed-assignment instance for %s: %d",
                childname, instance));
        }

        /*
         * Attach the instance number to the node. This allows
         * us to have multiple instances of the same pseudo
         * device, they will be named 'device@instance'. If this
         * breaks programs, we may need to special-case instance 0
         * into 'device'. Ick. devlinks appears to handle the
         * new names ok, so if only names in /dev are used
         * this may not be necessary.
         */
        (void) snprintf(name, sizeof (name), "%d", instance);
        DEVI(child)->devi_instance = instance;
        ddi_set_name_addr(child, name);
        return (DDI_SUCCESS);
    }

    case DDI_CTLOPS_UNINITCHILD:
    {
        dev_info_t *child = (dev_info_t *)arg;

        NDI_CONFIG_DEBUG((CE_NOTE,
            "DDI_CTLOPS_UNINITCHILD(%s, instance=%d)",
            ddi_driver_name(child), DEVI(child)->devi_instance));

        ddi_set_name_addr(child, NULL);

        return (DDI_SUCCESS);
    }

    case DDI_CTLOPS_DMAPMAPC:
    case DDI_CTLOPS_REPORTINT:
    case DDI_CTLOPS_REGSIZE:
    case DDI_CTLOPS_NREGS:
    case DDI_CTLOPS_NINTRS:
    case DDI_CTLOPS_SIDDEV:
    case DDI_CTLOPS_SLAVEONLY:
    case DDI_CTLOPS_AFFINITY:
    case DDI_CTLOPS_INTR_HILEVEL:
    case DDI_CTLOPS_XLATE_INTRS:
    case DDI_CTLOPS_POKE:
    case DDI_CTLOPS_PEEK:
        /*
         * These ops correspond to functions that "shouldn't" be called
         * by a pseudo driver.  So we whine when we're called.
         */
        cmn_err(CE_CONT, "%s%d: invalid op (%d) from %s%d\n",
            ddi_driver_name(dip), ddi_get_instance(dip), ctlop,
            ddi_driver_name(rdip), ddi_get_instance(rdip));
        return (DDI_FAILURE);

    case DDI_CTLOPS_ATTACH:
    case DDI_CTLOPS_BTOP:
    case DDI_CTLOPS_BTOPR:
    case DDI_CTLOPS_DETACH:
    case DDI_CTLOPS_DVMAPAGESIZE:
    case DDI_CTLOPS_IOMIN:
    case DDI_CTLOPS_POWER:
    case DDI_CTLOPS_PTOB:
    default:
        /*
         * The ops that we pass up (default).  We pass up memory
         * allocation oriented ops that we receive - these may be
         * associated with pseudo HBA drivers below us with target
         * drivers below them that use ddi memory allocation
         * interfaces like scsi_alloc_consistent_buf.
         */
        return (ddi_ctlops(dip, rdip, ctlop, arg, result));
    }
}