/*      $NetBSD: mii.c,v 1.59 2024/02/08 20:11:55 andvar Exp $  */

/*-
 * Copyright (c) 1998, 2000, 2020 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * 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.
 */

/*
 * MII bus layer, glues MII-capable network interface drivers to shareable
 * PHY drivers.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: mii.c,v 1.59 2024/02/08 20:11:55 andvar Exp $");

#define __IFMEDIA_PRIVATE

#include <sys/param.h>
#include <sys/device.h>
#include <sys/systm.h>
#include <sys/socket.h>

#include <net/if.h>
#include <net/if_media.h>

#include <dev/mii/mii.h>
#include <dev/mii/miivar.h>

#include "locators.h"

static int      mii_print(void *, const char *);

/*
 * Helper function used by network interface drivers, attaches PHYs
 * to the network interface driver parent.
 */
void
mii_attach(device_t parent, struct mii_data *mii, int capmask,
    int phyloc, int offloc, int flags)
{
        struct mii_attach_args ma;
        struct mii_softc *child;
        int offset = 0;
        uint16_t bmsr;
        int phymin, phymax;
        int locs[MIICF_NLOCS];
        int rv;

        KASSERT(mii->mii_media.ifm_lock != NULL);

        if (phyloc != MII_PHY_ANY && offloc != MII_OFFSET_ANY)
                panic("mii_attach: phyloc and offloc specified");

        if (phyloc == MII_PHY_ANY) {
                phymin = 0;
                phymax = MII_NPHY - 1;
        } else
                phymin = phymax = phyloc;

        mii_lock(mii);

        if ((mii->mii_flags & MIIF_INITDONE) == 0) {
                LIST_INIT(&mii->mii_phys);
                cv_init(&mii->mii_probe_cv, "mii_attach");
                mii->mii_flags |= MIIF_INITDONE;
        }

        /*
         * Probing temporarily unlocks the MII; wait until anyone
         * else who might be doing this to finish.
         */
        mii->mii_probe_waiters++;
        for (;;) {
                if (mii->mii_flags & MIIF_EXITING) {
                        mii->mii_probe_waiters--;
                        cv_signal(&mii->mii_probe_cv);
                        mii_unlock(mii);
                        return;
                }
                if ((mii->mii_flags & MIIF_PROBING) == 0)
                        break;
                cv_wait(&mii->mii_probe_cv, mii->mii_media.ifm_lock);
        }
        mii->mii_probe_waiters--;

        /* ...and old others off. */
        mii->mii_flags |= MIIF_PROBING;

        for (ma.mii_phyno = phymin; ma.mii_phyno <= phymax; ma.mii_phyno++) {
                /*
                 * Make sure we haven't already configured a PHY at this
                 * address.  This allows mii_attach() to be called
                 * multiple times.
                 */
                LIST_FOREACH(child, &mii->mii_phys, mii_list) {
                        if (child->mii_phy == ma.mii_phyno) {
                                /*
                                 * Yes, there is already something
                                 * configured at this address.
                                 */
                                offset++;
                                continue;
                        }
                }

                /*
                 * Check to see if there is a PHY at this address.  Note,
                 * many braindead PHYs report 0/0 in their ID registers,
                 * so we test for media in the BMSR.
                 */
                bmsr = 0;
                rv = (*mii->mii_readreg)(parent, ma.mii_phyno, MII_BMSR,
                    &bmsr);
                if ((rv != 0) || bmsr == 0 || bmsr == 0xffff ||
                    (bmsr & (BMSR_EXTSTAT | BMSR_MEDIAMASK)) == 0) {
                        /* Assume no PHY at this address. */
                        continue;
                }

                /*
                 * There is a PHY at this address.  If we were given an
                 * `offset' locator, skip this PHY if it doesn't match.
                 */
                if (offloc != MII_OFFSET_ANY && offloc != offset) {
                        offset++;
                        continue;
                }

                /*
                 * Extract the IDs.  Braindead PHYs will be handled by
                 * the `ukphy' driver, as we have no ID information to
                 * match on.
                 */
                ma.mii_id1 = ma.mii_id2 = 0;
                rv = (*mii->mii_readreg)(parent, ma.mii_phyno,
                    MII_PHYIDR1, &ma.mii_id1);
                rv |= (*mii->mii_readreg)(parent, ma.mii_phyno,
                    MII_PHYIDR2, &ma.mii_id2);
                if (rv != 0)
                        continue;

                ma.mii_data = mii;
                ma.mii_capmask = capmask;
                ma.mii_flags = flags | (mii->mii_flags & MIIF_INHERIT_MASK);

                locs[MIICF_PHY] = ma.mii_phyno;

                mii_unlock(mii);

                child = device_private(
                    config_found(parent, &ma, mii_print,
                                 CFARGS(.submatch = config_stdsubmatch,
                                        .iattr = "mii",
                                        .locators = locs)));
                if (child) {
                        /* Link it up in the parent's MII data. */
                        if (child->mii_flags & MIIF_AUTOTSLEEP)
                                cv_init(&child->mii_nway_cv, "miiauto");
                        else
                                callout_init(&child->mii_nway_ch, 0);
                        mii_lock(mii);
                        LIST_INSERT_HEAD(&mii->mii_phys, child, mii_list);
                        child->mii_offset = offset;
                        mii->mii_instance++;
                } else {
                        mii_lock(mii);
                }
                offset++;
        }

        /* All done! */
        mii->mii_flags &= ~MIIF_PROBING;
        cv_signal(&mii->mii_probe_cv);
        mii_unlock(mii);
}

void
mii_detach(struct mii_data *mii, int phyloc, int offloc)
{
        struct mii_softc *child, *nchild;
        bool exiting = false;

        if (phyloc != MII_PHY_ANY && offloc != MII_PHY_ANY)
                panic("mii_detach: phyloc and offloc specified");

        mii_lock(mii);

        if ((mii->mii_flags & MIIF_INITDONE) == 0 ||
            (mii->mii_flags & MIIF_EXITING) != 0) {
                mii_unlock(mii);
                return;
        }

        /*
         * XXX This is probably not the best hueristic.  Consider
         * XXX adding an argument to mii_detach().
         */
        if (phyloc == MII_PHY_ANY && MII_PHY_ANY == MII_OFFSET_ANY)
                exiting = true;

        if (exiting) {
                mii->mii_flags |= MIIF_EXITING;
                cv_broadcast(&mii->mii_probe_cv);
        }

        /* Wait for everyone else to get out. */
        mii->mii_probe_waiters++;
        for (;;) {
                /*
                 * If we've been waiting to do a less-than-exit, and
                 * *someone else* initiated an exit, then get out.
                 */
                if (!exiting && (mii->mii_flags & MIIF_EXITING) != 0) {
                        mii->mii_probe_waiters--;
                        cv_signal(&mii->mii_probe_cv);
                        mii_unlock(mii);
                        return;
                }
                if ((mii->mii_flags & MIIF_PROBING) == 0 &&
                    (!exiting || (exiting && mii->mii_probe_waiters == 1)))
                        break;
                cv_wait(&mii->mii_probe_cv, mii->mii_media.ifm_lock);
        }
        mii->mii_probe_waiters--;

        if (!exiting)
                mii->mii_flags |= MIIF_PROBING;

        LIST_FOREACH_SAFE(child, &mii->mii_phys, mii_list, nchild) {
                if (phyloc != MII_PHY_ANY || offloc != MII_OFFSET_ANY) {
                        if (phyloc != MII_PHY_ANY &&
                            phyloc != child->mii_phy)
                                continue;
                        if (offloc != MII_OFFSET_ANY &&
                            offloc != child->mii_offset)
                                continue;
                }
                LIST_REMOVE(child, mii_list);
                mii_unlock(mii);
                (void)config_detach(child->mii_dev, DETACH_FORCE);
                mii_lock(mii);
        }

        if (exiting) {
                cv_destroy(&mii->mii_probe_cv);
        } else {
                mii->mii_flags &= ~MIIF_PROBING;
                cv_signal(&mii->mii_probe_cv);
        }

        mii_unlock(mii);
}

static int
mii_print(void *aux, const char *pnp)
{
        struct mii_attach_args *ma = aux;

        if (pnp != NULL)
                aprint_normal("OUI 0x%06x model 0x%04x rev %d at %s",
                    MII_OUI(ma->mii_id1, ma->mii_id2), MII_MODEL(ma->mii_id2),
                    MII_REV(ma->mii_id2), pnp);

        aprint_normal(" phy %d", ma->mii_phyno);
        return UNCONF;
}

static inline int
phy_service(struct mii_softc *sc, struct mii_data *mii, int cmd)
{

        if (!device_is_active(sc->mii_dev))
                return ENXIO;
        return PHY_SERVICE(sc, mii, cmd);
}

int
mii_ifmedia_change(struct mii_data *mii)
{

        KASSERT(mii_locked(mii) ||
                ifmedia_islegacy(&mii->mii_media));
        return ifmedia_change(&mii->mii_media, mii->mii_ifp);
}

/*
 * Media changed; notify all PHYs.
 */
int
mii_mediachg(struct mii_data *mii)
{
        struct mii_softc *child;
        int rv = 0;

        IFMEDIA_LOCK_FOR_LEGACY(&mii->mii_media);
        KASSERT(mii_locked(mii));

        mii->mii_media_status = 0;
        mii->mii_media_active = IFM_NONE;

        LIST_FOREACH(child, &mii->mii_phys, mii_list) {
                rv = phy_service(child, mii, MII_MEDIACHG);
                if (rv)
                        break;
        }
        IFMEDIA_UNLOCK_FOR_LEGACY(&mii->mii_media);
        return rv;
}

/*
 * Call the PHY tick routines, used during autonegotiation.
 */
void
mii_tick(struct mii_data *mii)
{
        struct mii_softc *child;

        IFMEDIA_LOCK_FOR_LEGACY(&mii->mii_media);
        KASSERT(mii_locked(mii));

        LIST_FOREACH(child, &mii->mii_phys, mii_list)
                (void)phy_service(child, mii, MII_TICK);

        IFMEDIA_UNLOCK_FOR_LEGACY(&mii->mii_media);
}

/*
 * Get media status from PHYs.
 */
void
mii_pollstat(struct mii_data *mii)
{
        struct mii_softc *child;

        IFMEDIA_LOCK_FOR_LEGACY(&mii->mii_media);
        KASSERT(mii_locked(mii));

        mii->mii_media_status = 0;
        mii->mii_media_active = IFM_NONE;

        LIST_FOREACH(child, &mii->mii_phys, mii_list)
                (void)phy_service(child, mii, MII_POLLSTAT);

        IFMEDIA_UNLOCK_FOR_LEGACY(&mii->mii_media);
}

/*
 * Inform the PHYs that the interface is down.
 */
void
mii_down(struct mii_data *mii)
{
        struct mii_softc *child;

        IFMEDIA_LOCK_FOR_LEGACY(&mii->mii_media);
        KASSERT(mii_locked(mii));

        LIST_FOREACH(child, &mii->mii_phys, mii_list)
                (void)phy_service(child, mii, MII_DOWN);

        IFMEDIA_UNLOCK_FOR_LEGACY(&mii->mii_media);
}

static unsigned char
bitreverse(unsigned char x)
{
        static const unsigned char nibbletab[16] = {
                0, 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7, 15
        };

        return ((nibbletab[x & 15] << 4) | nibbletab[x >> 4]);
}

u_int
mii_oui(uint16_t id1, uint16_t id2)
{
        u_int h;

        h = (id1 << 6) | (id2 >> 10);

        return ((bitreverse(h >> 16) << 16) |
                (bitreverse((h >> 8) & 255) << 8) |
                bitreverse(h & 255));
}