/*
 * 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.
 */

/*
 * Copyright 2023 Oxide Computer Company
 */

#include <sys/systm.h>
#include <sys/pathname.h>
#include <sys/modctl.h>
#include <sys/sunndi.h>
#include <sys/sunmdi.h>
#include <sys/mdi_impldefs.h>
#include <sys/promif.h>

struct parinfo {
        dev_info_t *dip;
        dev_info_t *pdip;
};

/*
 * internal functions
 */
static int resolve_devfs_name(char *, char *);
static dev_info_t *find_alternate_node(dev_info_t *, major_t);
static dev_info_t *get_parent(dev_info_t *, struct parinfo *);
static int i_devi_to_promname(dev_info_t *, char *, dev_info_t **alt_dipp);

/* internal global data */
static struct modlmisc modlmisc = {
        &mod_miscops, "bootdev misc module 1.22"
};

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

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

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

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

/*
 * convert a prom device path to an equivalent path in /devices
 * Does not deal with aliases.  Does deal with pathnames which
 * are not fully qualified.  This routine is generalized
 * to work across several flavors of OBP
 */
int
i_promname_to_devname(char *prom_name, char *ret_buf)
{
        if (prom_name == NULL || ret_buf == NULL ||
            (strlen(prom_name) >= MAXPATHLEN)) {
                return (EINVAL);
        }
        if (i_ddi_prompath_to_devfspath(prom_name, ret_buf) != DDI_SUCCESS)
                return (EINVAL);

        return (0);
}

/*
 * The function is to get prom name according non-client dip node.
 * And the function will set the alternate node of dip to alt_dip
 * if it is exist which must be PROM node.
 */
static int
i_devi_to_promname(dev_info_t *dip, char *prom_path, dev_info_t **alt_dipp)
{
        dev_info_t *pdip, *cdip, *idip;
        char *unit_address, *nodename;
        major_t major;
        int depth, old_depth = 0;
        struct parinfo *parinfo = NULL;
        struct parinfo *info;
        int ret = 0;

        if (MDI_CLIENT(dip))
                return (EINVAL);

        if (ddi_pathname_obp(dip, prom_path) != NULL) {
                return (0);
        }
        /*
         * ddi_pathname_obp return NULL, but the obp path still could
         * be different with the devfs path name, so need use a parents
         * stack to compose the path name string layer by layer.
         */

        /* find the closest ancestor which is a prom node */
        pdip = dip;
        parinfo = kmem_alloc(OBP_STACKDEPTH * sizeof (*parinfo),
            KM_SLEEP);
        for (depth = 0; ndi_dev_is_prom_node(pdip) == 0; depth++) {
                if (depth == OBP_STACKDEPTH) {
                        ret = EINVAL;
                        /* must not have been an obp node */
                        goto out;
                }
                pdip = get_parent(pdip, &parinfo[depth]);
        }
        old_depth = depth;
        ASSERT(pdip);   /* at least root is prom node */
        if (pdip)
                (void) ddi_pathname(pdip, prom_path);

        ndi_hold_devi(pdip);

        for (depth = old_depth; depth > 0; depth--) {
                info = &parinfo[depth - 1];
                idip = info->dip;
                nodename = ddi_node_name(idip);
                unit_address = ddi_get_name_addr(idip);

                if (pdip) {
                        major = ddi_driver_major(idip);
                        cdip = find_alternate_node(pdip, major);
                        ndi_rele_devi(pdip);
                        if (cdip) {
                                nodename = ddi_node_name(cdip);
                        }
                }

                /*
                 * node name + unitaddr to the prom_path
                 */
                (void) strcat(prom_path, "/");
                (void) strcat(prom_path, nodename);
                if (unit_address && (*unit_address)) {
                        (void) strcat(prom_path, "@");
                        (void) strcat(prom_path, unit_address);
                }
                pdip = cdip;
        }

        if (pdip) {
                ndi_rele_devi(pdip); /* hold from find_alternate_node */
        }
        /*
         * Now pdip is the alternate node which is same hierarchy as dip
         * if it exists.
         */
        *alt_dipp = pdip;
out:
        if (parinfo) {
                /* release holds from get_parent() */
                for (depth = old_depth; depth > 0; depth--) {
                        info = &parinfo[depth - 1];
                        if (info && info->pdip)
                                ndi_rele_devi(info->pdip);
                }
                kmem_free(parinfo, OBP_STACKDEPTH * sizeof (*parinfo));
        }
        return (ret);
}

/*
 * translate a devfs pathname to one that will be acceptable
 * by the prom.  In most cases, there is no translation needed.
 * For systems supporting generically named devices, the prom
 * may support nodes such as 'disk' that do not have any unit
 * address information (i.e. target,lun info).  If this is the
 * case, the ddi framework will reject the node as invalid and
 * populate the devinfo tree with nodes froms the .conf file
 * (e.g. sd).  In this case, the names that show up in /devices
 * are sd - since the prom only knows about 'disk' nodes, this
 * routine detects this situation and does the conversion
 * There are also cases such as pluto where the disk node in the
 * prom is named "SUNW,ssd" but in /devices the name is "ssd".
 *
 * If MPxIO is enabled, the translation involves following
 * pathinfo nodes to the "best" parent.
 *
 * return a 0 on success with the new device string in ret_buf.
 * Otherwise return the appropriate error code as we may be called
 * from the openprom driver.
 */
int
i_devname_to_promname(char *dev_name, char *ret_buf, size_t len)
{
        dev_info_t *dip, *pdip, *cdip, *alt_dip = NULL;
        mdi_pathinfo_t *pip = NULL;
        char *dev_path, *prom_path;
        char *unit_address, *minorname, *nodename;
        major_t major;
        char *rptr, *optr, *offline;
        size_t olen, rlen;
        int ret = 0;

        /* do some sanity checks */
        if ((dev_name == NULL) || (ret_buf == NULL) ||
            (strlen(dev_name) > MAXPATHLEN)) {
                return (EINVAL);
        }

        /*
         * Convert to a /devices name. Fail the translation if
         * the name doesn't exist.
         */
        dev_path = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
        if (resolve_devfs_name(dev_name, dev_path) != 0 ||
            strncmp(dev_path, "/devices/", 9) != 0) {
                kmem_free(dev_path, MAXPATHLEN);
                return (EINVAL);
        }
        dev_name = dev_path + sizeof ("/devices") - 1;

        bzero(ret_buf, len);

        if (prom_finddevice(dev_name) != OBP_BADNODE) {
                /* we are done */
                (void) snprintf(ret_buf, len, "%s", dev_name);
                kmem_free(dev_path, MAXPATHLEN);
                return (0);
        }

        /*
         * if we get here, then some portion of the device path is
         * not understood by the prom.  We need to look for alternate
         * names (e.g. replace ssd by disk) and mpxio enabled devices.
         */
        dip = e_ddi_hold_devi_by_path(dev_name, 0);
        if (dip == NULL) {
                cmn_err(CE_NOTE, "cannot find dip for %s", dev_name);
                kmem_free(dev_path, MAXPATHLEN);
                return (EINVAL);
        }

        prom_path = kmem_zalloc(MAXPATHLEN, KM_SLEEP);
        rlen = len;
        rptr = ret_buf;

        if (!MDI_CLIENT(dip)) {
                ret = i_devi_to_promname(dip, prom_path, &alt_dip);
                if (ret == 0) {
                        minorname = strrchr(dev_name, ':');
                        if (minorname && (minorname[1] != '\0')) {
                                (void) strcat(prom_path, minorname);
                        }
                        (void) snprintf(rptr, rlen, "%s", prom_path);
                }
        } else {
                /*
                 * if get to here, means dip is a vhci client
                 */
                offline = kmem_zalloc(len, KM_SLEEP); /* offline paths */
                olen = len;
                optr = offline;
                /*
                 * The following code assumes that the phci client is at leaf
                 * level.
                 */
                ndi_devi_enter(dip);
                while ((pip = mdi_get_next_phci_path(dip, pip)) != NULL) {
                        /*
                         * walk all paths associated to the client node
                         */
                        bzero(prom_path, MAXPATHLEN);

                        /*
                         * replace with mdi_hold_path() when mpxio goes into
                         * genunix
                         */
                        MDI_PI_LOCK(pip);
                        MDI_PI_HOLD(pip);
                        MDI_PI_UNLOCK(pip);

                        if (mdi_pi_pathname_obp(pip, prom_path) != NULL) {
                                /*
                                 * The path has different obp path
                                 */
                                goto minor_pathinfo;
                        }

                        pdip = mdi_pi_get_phci(pip);
                        ndi_hold_devi(pdip);

                        /*
                         * Get obp path name of the phci node firstly.
                         * NOTE: if the alternate node of pdip exists,
                         * the third argument of the i_devi_to_promname()
                         * would be set to the alternate node.
                         */
                        (void) i_devi_to_promname(pdip, prom_path, &alt_dip);
                        if (alt_dip != NULL) {
                                ndi_rele_devi(pdip);
                                pdip = alt_dip;
                                ndi_hold_devi(pdip);
                        }

                        nodename = ddi_node_name(dip);
                        unit_address = MDI_PI(pip)->pi_addr;

                        major = ddi_driver_major(dip);
                        cdip = find_alternate_node(pdip, major);

                        if (cdip) {
                                nodename = ddi_node_name(cdip);
                        }
                        /*
                         * node name + unitaddr to the prom_path
                         */
                        (void) strcat(prom_path, "/");
                        (void) strcat(prom_path, nodename);
                        if (unit_address && (*unit_address)) {
                                (void) strcat(prom_path, "@");
                                (void) strcat(prom_path, unit_address);
                        }
                        if (cdip) {
                                /* hold from find_alternate_node */
                                ndi_rele_devi(cdip);
                        }
                        ndi_rele_devi(pdip);
minor_pathinfo:
                        minorname = strrchr(dev_name, ':');
                        if (minorname && (minorname[1] != '\0')) {
                                (void) strcat(prom_path, minorname);
                        }

                        if (MDI_PI_IS_ONLINE(pip)) {
                                (void) snprintf(rptr, rlen, "%s", prom_path);
                                rlen -= strlen(rptr) + 1;
                                rptr += strlen(rptr) + 1;
                                if (rlen <= 0) /* drop paths we can't store */
                                        break;
                        } else {        /* path is offline */
                                (void) snprintf(optr, olen, "%s", prom_path);
                                olen -= strlen(optr) + 1;
                                if (olen > 0) /* drop paths we can't store */
                                        optr += strlen(optr) + 1;
                        }
                        MDI_PI_LOCK(pip);
                        MDI_PI_RELE(pip);
                        if (MDI_PI(pip)->pi_ref_cnt == 0)
                                cv_broadcast(&MDI_PI(pip)->pi_ref_cv);
                        MDI_PI_UNLOCK(pip);
                }
                ndi_devi_exit(dip);
                ret = 0;
                if (rlen > 0) {
                        /* now add as much of offline to ret_buf as possible */
                        bcopy(offline, rptr, rlen);
                }
                kmem_free(offline, len);
        }
        /* release hold from e_ddi_hold_devi_by_path() */
        ndi_rele_devi(dip);
        ret_buf[len - 1] = '\0';
        ret_buf[len - 2] = '\0';
        kmem_free(dev_path, MAXPATHLEN);
        kmem_free(prom_path, MAXPATHLEN);

        return (ret);
}

/*
 * check for a possible substitute node.  This routine searches the
 * children of parent_dip, looking for a node that:
 *      1. is a prom node
 *      2. binds to the same major number
 *      3. there is no need to verify that the unit-address information
 *              match since it is likely that the substitute node
 *              will have none (e.g. disk) - this would be the reason the
 *              framework rejected it in the first place.
 *
 * assumes parent_dip is held
 */
static dev_info_t *
find_alternate_node(dev_info_t *parent_dip, major_t major)
{
        dev_info_t *child_dip;

        /* lock down parent to keep children from being removed */
        ndi_devi_enter(parent_dip);
        for (child_dip = ddi_get_child(parent_dip); child_dip != NULL;
            child_dip = ddi_get_next_sibling(child_dip)) {

                /* look for obp node with matching major */
                if ((ndi_dev_is_prom_node(child_dip) != 0) &&
                    (ddi_driver_major(child_dip) == major)) {
                        ndi_hold_devi(child_dip);
                        break;
                }
        }
        ndi_devi_exit(parent_dip);
        return (child_dip);
}

/*
 * given an absolute pathname, convert it, if possible, to a devfs
 * name.  Examples:
 * /dev/rsd3a to /pci@1f,4000/glm@3/sd@0,0:a
 * /dev/dsk/c0t0d0s0 to /pci@1f,4000/glm@3/sd@0,0:a
 * /devices/pci@1f,4000/glm@3/sd@0,0:a to /pci@1f,4000/glm@3/sd@0,0:a
 * /pci@1f,4000/glm@3/sd@0,0:a unchanged
 *
 * This routine deals with symbolic links, physical pathname with and
 * without /devices stripped. Returns 0 on success or -1 on failure.
 */
static int
resolve_devfs_name(char *name, char *buffer)
{
        int error;
        char *fullname = NULL;
        struct pathname pn, rpn;

        /* if not a /dev or /device name, prepend /devices */
        if (strncmp(name, "/dev/", 5) != 0 &&
            strncmp(name, "/devices/", 9) != 0) {
                fullname = kmem_alloc(MAXPATHLEN, KM_SLEEP);
                (void) snprintf(fullname, MAXPATHLEN, "/devices%s", name);
                name = fullname;
        }

        if (pn_get(name, UIO_SYSSPACE, &pn) != 0) {
                if (fullname)
                        kmem_free(fullname, MAXPATHLEN);
                return (-1);
        }

        pn_alloc(&rpn);
        error = lookuppn(&pn, &rpn, FOLLOW, NULL, NULL);
        if (error == 0)
                bcopy(rpn.pn_path, buffer, rpn.pn_pathlen);

        pn_free(&pn);
        pn_free(&rpn);
        if (fullname)
                kmem_free(fullname, MAXPATHLEN);

        return (error);
}

/*
 * If bootstring contains a device path, we need to convert to a format
 * the prom will understand.  To do so, we convert the existing path to
 * a prom-compatible path and return the value of new_path.  If the
 * caller specifies new_path as NULL, we allocate an appropriately
 * sized new_path on behalf of the caller.  If the caller invokes this
 * function with new_path = NULL, they must do so from a context in
 * which it is safe to perform a sleeping memory allocation.
 */
char *
i_convert_boot_device_name(char *cur_path, char *new_path, size_t *len)
{
        char *ptr;
        int rval;

        ASSERT(cur_path != NULL && len != NULL);
        ASSERT(new_path == NULL || *len >= MAXPATHLEN);

        if (new_path == NULL) {
                *len = MAXPATHLEN + MAXNAMELEN;
                new_path = kmem_alloc(*len, KM_SLEEP);
        }

        if ((ptr = strchr(cur_path, ' ')) != NULL)
                *ptr = '\0';

        rval = i_devname_to_promname(cur_path, new_path, *len);

        if (ptr != NULL)
                *ptr = ' ';

        if (rval == 0) {
                if (ptr != NULL) {
                        (void) snprintf(new_path + strlen(new_path),
                            *len - strlen(new_path), "%s", ptr);
                }
        } else {                /* the conversion failed */
                (void) snprintf(new_path, *len, "%s", cur_path);
        }

        return (new_path);
}

/*
 * Get the parent dip.
 */
static dev_info_t *
get_parent(dev_info_t *dip, struct parinfo *info)
{
        dev_info_t *pdip;

        pdip = ddi_get_parent(dip);
        ndi_hold_devi(pdip);
        info->dip = dip;
        info->pdip = pdip;
        return (pdip);
}