sun4v/io/mdesc.c

/*
 * 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 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


/*
 * sun4v machine description driver
 */

#include <sys/types.h>
#include <sys/file.h>
#include <sys/errno.h>
#include <sys/open.h>
#include <sys/cred.h>
#include <sys/uio.h>
#include <sys/stat.h>
#include <sys/ksynch.h>
#include <sys/modctl.h>
#include <sys/conf.h>
#include <sys/devops.h>
#include <sys/debug.h>
#include <sys/cmn_err.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>

#include <sys/mdesc.h>
#include <sys/mach_descrip.h>

#define MDESC_NAME  "mdesc"

/*
 * Operational state flags
 */

#define MDESC_GOT_HANDLE    0x10        /* Got mdesc handle */
#define MDESC_BUSY      0x20        /* Device is busy */

static void     *mdesc_state_head;
static vmem_t       *mdesc_minor;
static uint16_t     mdesc_max_opens = 256;
static uint16_t     mdesc_opens = 0;
static int      mdesc_attached = 0;
static dev_info_t   *mdesc_devi;
static kmutex_t     mdesc_lock;

struct mdesc_state {
    int     instance;
    dev_t       dev;
    kmutex_t    lock;
    kcondvar_t  cv;
    size_t      mdesc_len;
    md_t        *mdesc;
    int     flags;
};

typedef struct mdesc_state mdesc_state_t;

static int mdesc_getinfo(dev_info_t *, ddi_info_cmd_t, void *, void **);
static int mdesc_attach(dev_info_t *, ddi_attach_cmd_t);
static int mdesc_detach(dev_info_t *, ddi_detach_cmd_t);
static int mdesc_open(dev_t *, int, int, cred_t *);
static int mdesc_close(dev_t, int, int, cred_t *);
static int mdesc_read(dev_t, struct uio *, cred_t *);
static int mdesc_write(dev_t, struct uio *, cred_t *);
static int mdesc_rw(dev_t, struct uio *, enum uio_rw);
static int mdesc_ioctl(dev_t, int, intptr_t, int, cred_t *, int *);

static struct cb_ops mdesc_cb_ops = {
    mdesc_open,     /* cb_open */
    mdesc_close,        /* cb_close */
    nodev,          /* cb_strategy */
    nodev,          /* cb_print */
    nodev,          /* cb_dump */
    mdesc_read,     /* cb_read */
    nodev,          /* cb_write */
    mdesc_ioctl,        /* cb_ioctl */
    nodev,          /* cb_devmap */
    nodev,          /* cb_mmap */
    nodev,          /* cb_segmap */
    nochpoll,       /* cb_chpoll */
    ddi_prop_op,        /* cb_prop_op */
    (struct streamtab *)NULL, /* cb_str */
    D_MP | D_64BIT,     /* cb_flag */
    CB_REV,         /* cb_rev */
    nodev,          /* cb_aread */
    nodev           /* cb_awrite */
};

static struct dev_ops mdesc_dev_ops = {
    DEVO_REV,       /* devo_rev */
    0,          /* devo_refcnt */
    mdesc_getinfo,      /* devo_getinfo */
    nulldev,        /* devo_identify */
    nulldev,        /* devo_probe */
    mdesc_attach,       /* devo_attach */
    mdesc_detach,       /* devo_detach */
    nodev,          /* devo_reset */
    &mdesc_cb_ops,      /* devo_cb_ops */
    (struct bus_ops *)NULL, /* devo_bus_ops */
    nulldev,        /* devo_power */
    ddi_quiesce_not_needed,     /* quiesce */
};

static struct modldrv modldrv = {
    &mod_driverops,
    "Machine Description Driver",
    &mdesc_dev_ops};

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


int
_init(void)
{
    int retval;

    if ((retval = ddi_soft_state_init(&mdesc_state_head,
        sizeof (struct mdesc_state), mdesc_max_opens)) != 0)
        return (retval);
    if ((retval = mod_install(&modlinkage)) != 0) {
        ddi_soft_state_fini(&mdesc_state_head);
        return (retval);
    }

    return (retval);
}


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


int
_fini(void)
{
    int retval;

    if ((retval = mod_remove(&modlinkage)) != 0)
        return (retval);
    ddi_soft_state_fini(&mdesc_state_head);

    return (retval);
}


/*ARGSUSED*/
static int
mdesc_getinfo(dev_info_t *dip, ddi_info_cmd_t cmd, void *arg, void **resultp)
{
    struct mdesc_state *mdsp;
    int retval = DDI_FAILURE;

    ASSERT(resultp != NULL);

    switch (cmd) {
    case DDI_INFO_DEVT2DEVINFO:
        mdsp = ddi_get_soft_state(mdesc_state_head,
            getminor((dev_t)arg));
        if (mdsp != NULL) {
            *resultp = mdesc_devi;
            retval = DDI_SUCCESS;
        } else
            *resultp = NULL;
        break;
    case DDI_INFO_DEVT2INSTANCE:
        *resultp = (void *)(uintptr_t)getminor((dev_t)arg);
        retval = DDI_SUCCESS;
        break;
    }

    return (retval);
}


static int
mdesc_attach(dev_info_t *dip, ddi_attach_cmd_t cmd)
{
    int instance = ddi_get_instance(dip);

    switch (cmd) {
    case DDI_ATTACH:

        if (ddi_create_minor_node(dip, MDESC_NAME, S_IFCHR, instance,
            DDI_PSEUDO, 0) != DDI_SUCCESS) {
            cmn_err(CE_WARN, "%s@%d: Unable to create minor node",
                MDESC_NAME, instance);
            return (DDI_FAILURE);
        }
        ddi_report_dev(dip);
        mdesc_devi = dip;
        mdesc_minor = vmem_create("mdesc_minor", (void *) 1,
            mdesc_max_opens, 1, NULL, NULL, NULL, 0,
            VM_SLEEP | VMC_IDENTIFIER);
        mutex_init(&mdesc_lock, NULL, MUTEX_DRIVER, NULL);
        mdesc_attached = 1;
        return (DDI_SUCCESS);
    case DDI_RESUME:
        return (DDI_SUCCESS);
    default:
        return (DDI_FAILURE);
    }
}

/*ARGSUSED*/
static int
mdesc_detach(dev_info_t *dip, ddi_detach_cmd_t cmd)
{
    switch (cmd) {
    case DDI_DETACH:
        mutex_destroy(&mdesc_lock);
        vmem_destroy(mdesc_minor);
        ddi_remove_minor_node(mdesc_devi, NULL);
        mdesc_attached = 0;
        return (DDI_SUCCESS);

    case DDI_SUSPEND:
        return (DDI_SUCCESS);

    default:
        return (DDI_FAILURE);
    }
}

static void
mdesc_destroy_state(mdesc_state_t *mdsp)
{
    minor_t minor = getminor(mdsp->dev);

    if (mdsp->flags & MDESC_GOT_HANDLE)
        (void) md_fini_handle(mdsp->mdesc);

    cv_destroy(&mdsp->cv);
    mutex_destroy(&mdsp->lock);
    ddi_soft_state_free(mdesc_state_head, minor);
    vmem_free(mdesc_minor, (void *)(uintptr_t)minor, 1);
}

static mdesc_state_t *
mdesc_create_state(dev_t *devp)
{
    major_t major;
    minor_t minor;
    mdesc_state_t *mdsp;

    minor = (minor_t)(uintptr_t)vmem_alloc(mdesc_minor, 1,
        VM_BESTFIT | VM_SLEEP);

    if (ddi_soft_state_zalloc(mdesc_state_head, minor) !=
        DDI_SUCCESS) {
        cmn_err(CE_WARN, "%s@%d: Unable to allocate state",
            MDESC_NAME, minor);
        vmem_free(mdesc_minor, (void *)(uintptr_t)minor, 1);
        return (NULL);
    }

    mdsp = ddi_get_soft_state(mdesc_state_head, minor);

    if (devp != NULL) {
        major = getemajor(*devp);
    } else {
        major = ddi_driver_major(mdesc_devi);
    }

    mdsp->dev = makedevice(major, minor);

    if (devp != NULL)
        *devp = mdsp->dev;

    mdsp->instance = minor;

    mutex_init(&mdsp->lock, NULL, MUTEX_DRIVER, NULL);

    cv_init(&mdsp->cv, NULL, CV_DRIVER, NULL);

    mdsp->mdesc = md_get_handle();

    if (mdsp->mdesc == NULL) {
        mdesc_destroy_state(mdsp);
        return (NULL);
    }
    mdsp->flags |= MDESC_GOT_HANDLE;

    mdsp->mdesc_len = md_get_bin_size(mdsp->mdesc);

    if (mdsp->mdesc_len == 0) {
        mdesc_destroy_state(mdsp);
        mdsp = NULL;
    }

    return (mdsp);
}


/*ARGSUSED*/
static int
mdesc_open(dev_t *devp, int flag, int otyp, cred_t *credp)
{
    struct mdesc_state *mdsp;

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

    mutex_enter(&mdesc_lock);

    if (mdesc_opens >= mdesc_max_opens) {
        mutex_exit(&mdesc_lock);
        return (ENXIO);
    }

    mdsp = mdesc_create_state(devp);

    if (mdsp == NULL) {
        mutex_exit(&mdesc_lock);
        return (ENXIO);
    }

    mdesc_opens++;

    mutex_exit(&mdesc_lock);

    return (0);
}

/*ARGSUSED*/
static int
mdesc_close(dev_t dev, int flag, int otyp, cred_t *credp)
{
    struct mdesc_state *mdsp;
    int instance = getminor(dev);

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

    mutex_enter(&mdesc_lock);
    if (mdesc_opens == 0) {
        mutex_exit(&mdesc_lock);
        return (0);
    }
    mutex_exit(&mdesc_lock);

    if ((mdsp = ddi_get_soft_state(mdesc_state_head, instance)) == NULL)
        return (ENXIO);

    ASSERT(mdsp->instance == instance);

    mdesc_destroy_state(mdsp);
    mutex_enter(&mdesc_lock);
    mdesc_opens--;
    mutex_exit(&mdesc_lock);

    return (0);
}


/*ARGSUSED*/
static int
mdesc_read(dev_t dev, struct uio *uiop, cred_t *credp)
{
    return (mdesc_rw(dev, uiop, UIO_READ));
}


/*ARGSUSED*/
static int
mdesc_write(dev_t dev, struct uio *uiop, cred_t *credp)
{
    return (ENXIO); /* This driver version does not allow updates */
}


static int
mdesc_rw(dev_t dev, struct uio *uiop, enum uio_rw rw)
{
    struct mdesc_state *mdsp;
    int instance = getminor(dev);
    size_t len;
    int retval;
    caddr_t buf;

    len = uiop->uio_resid;

    if ((mdsp = ddi_get_soft_state(mdesc_state_head, instance)) == NULL)
        return (ENXIO);

    ASSERT(mdsp->instance == instance);

    if (len == 0)
        return (0);

    mutex_enter(&mdsp->lock);

    while (mdsp->flags & MDESC_BUSY) {
        if (cv_wait_sig(&mdsp->cv, &mdsp->lock) == 0) {
            mutex_exit(&mdsp->lock);
            return (EINTR);
        }
    }

    if (uiop->uio_offset < 0 || uiop->uio_offset > mdsp->mdesc_len) {
        mutex_exit(&mdsp->lock);
        return (EINVAL);
    }

    if (len > (mdsp->mdesc_len - uiop->uio_offset))
        len = mdsp->mdesc_len - uiop->uio_offset;

        /* already checked that offset<mdesc_len above */
    if (len == 0) {
        mutex_exit(&mdsp->lock);
        return (rw == UIO_WRITE ? ENOSPC : 0);
    }

    mdsp->flags |= MDESC_BUSY;
    mutex_exit(&mdsp->lock);

    buf = md_get_md_raw(mdsp->mdesc);
    if (buf == NULL)
        return (ENXIO);

    retval = uiomove((void *)(buf + uiop->uio_offset),
        len, rw, uiop);

    mutex_enter(&mdsp->lock);
    mdsp->flags &= ~MDESC_BUSY;
    cv_broadcast(&mdsp->cv);
    mutex_exit(&mdsp->lock);

    return (retval);
}


/*ARGSUSED*/
static int
mdesc_ioctl(dev_t dev, int cmd, intptr_t arg, int mode, cred_t *credp,
    int *rvalp)
{
    struct mdesc_state *mdsp;
    int instance = getminor(dev);

    if ((mdsp = ddi_get_soft_state(mdesc_state_head, instance)) == NULL)
        return (ENXIO);

    ASSERT(mdsp->instance == instance);

    switch (cmd) {
    case MDESCIOCGSZ: {
        /*
         * We are not guaranteed that ddi_copyout(9F) will read
         * atomically anything larger than a byte.  Therefore we
         * must duplicate the size before copying it out to the user.
         */
        size_t sz = mdsp->mdesc_len;

        if (!(mode & FREAD))
            return (EACCES);

#ifdef _MULTI_DATAMODEL
        switch (ddi_model_convert_from(mode & FMODELS)) {
        case DDI_MODEL_ILP32: {
            size32_t sz32 = (size32_t)sz;
            if (ddi_copyout(&sz32, (void *)arg, sizeof (size32_t),
                mode) != 0)
                return (EFAULT);
            return (0);
        }
        case DDI_MODEL_NONE:
            if (ddi_copyout(&sz, (void *)arg, sizeof (size_t),
                mode) != 0)
                return (EFAULT);
            return (0);
        default:
            cmn_err(CE_WARN,
                "mdesc: Invalid data model %d in ioctl\n",
                ddi_model_convert_from(mode & FMODELS));
            return (ENOTSUP);
        }
#else /* ! _MULTI_DATAMODEL */
        if (ddi_copyout(&sz, (void *)arg, sizeof (size_t), mode) != 0)
            return (EFAULT);
        return (0);
#endif /* _MULTI_DATAMODEL */
    }

    default:
        return (ENOTTY);
    }
}