/*      $NetBSD: amhphy.c,v 1.27 2024/02/08 19:44:08 andvar Exp $       */

/*
 * Copyright 2001 Wasabi Systems, Inc.
 * All rights reserved.
 *
 * Written by Jason R. Thorpe for Wasabi Systems, Inc.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed for the NetBSD Project by
 *      Wasabi Systems, Inc.
 * 4. The name of Wasabi Systems, Inc. may not be used to endorse
 *    or promote products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
 * 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.
 */

/*
 * Driver for the 10BASE-T portion of the AMD Am79c901 PHY.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: amhphy.c,v 1.27 2024/02/08 19:44:08 andvar Exp $");

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

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

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

#include <dev/mii/amhphyreg.h>

static int      amhphymatch(device_t, cfdata_t, void *);
static void     amhphyattach(device_t, device_t, void *);

CFATTACH_DECL_NEW(amhphy, sizeof(struct mii_softc),
    amhphymatch, amhphyattach, mii_phy_detach, mii_phy_activate);

static int      amhphy_service(struct mii_softc *, struct mii_data *, int);
static void     amhphy_status(struct mii_softc *);

static const struct mii_phy_funcs amhphy_funcs = {
        amhphy_service, amhphy_status, mii_phy_reset,
};

static const struct mii_phydesc amhphys[] = {
        MII_PHY_DESC(yyAMD, 79c901),
        MII_PHY_END,
};

static int
amhphymatch(device_t parent, cfdata_t match, void *aux)
{
        struct mii_attach_args *ma = aux;

        if (mii_phy_match(ma, amhphys) != NULL)
                return 10;

        return 0;
}

static void
amhphyattach(device_t parent, device_t self, void *aux)
{
        struct mii_softc *sc = device_private(self);
        struct mii_attach_args *ma = aux;
        struct mii_data *mii = ma->mii_data;
        const struct mii_phydesc *mpd;

        mpd = mii_phy_match(ma, amhphys);
        aprint_naive(": Media interface\n");
        aprint_normal(": %s, rev. %d\n", mpd->mpd_name, MII_REV(ma->mii_id2));

        sc->mii_dev = self;
        sc->mii_inst = mii->mii_instance;
        sc->mii_phy = ma->mii_phyno;
        sc->mii_funcs = &amhphy_funcs;
        sc->mii_pdata = mii;
        sc->mii_flags = ma->mii_flags;

        mii_lock(mii);

        PHY_RESET(sc);

        PHY_READ(sc, MII_BMSR, &sc->mii_capabilities);
        sc->mii_capabilities &= ma->mii_capmask;

        mii_unlock(mii);

        mii_phy_add_media(sc);
}

static int
amhphy_service(struct mii_softc *sc, struct mii_data *mii, int cmd)
{
        struct ifmedia_entry *ife = mii->mii_media.ifm_cur;
        uint16_t reg;

        KASSERT(mii_locked(mii));

        switch (cmd) {
        case MII_POLLSTAT:
                /* If we're not polling our PHY instance, just return. */
                if (IFM_INST(ife->ifm_media) != sc->mii_inst)
                        return 0;
                break;

        case MII_MEDIACHG:
                /*
                 * If the media indicates a different PHY instance,
                 * isolate ourselves.
                 */
                if (IFM_INST(ife->ifm_media) != sc->mii_inst) {
                        PHY_READ(sc, MII_BMCR, &reg);
                        PHY_WRITE(sc, MII_BMCR, reg | BMCR_ISO);
                        return 0;
                }

                /* If the interface is not up, don't do anything. */
                if ((mii->mii_ifp->if_flags & IFF_UP) == 0)
                        break;

                mii_phy_setmedia(sc);
                break;

        case MII_TICK:
                /* If we're not currently selected, just return. */
                if (IFM_INST(ife->ifm_media) != sc->mii_inst)
                        return 0;

                if (mii_phy_tick(sc) == EJUSTRETURN)
                        return 0;
                break;

        case MII_DOWN:
                mii_phy_down(sc);
                return 0;
        }

        /* Update the media status. */
        mii_phy_status(sc);

        /* Callback if something changed. */
        mii_phy_update(sc, cmd);
        return 0;
}

static void
amhphy_status(struct mii_softc *sc)
{
        struct mii_data *mii = sc->mii_pdata;
        struct ifmedia_entry *ife = mii->mii_media.ifm_cur;
        uint16_t bmsr, bmcr, ssr;

        KASSERT(mii_locked(mii));

        mii->mii_media_status = IFM_AVALID;
        mii->mii_media_active = IFM_ETHER;

        PHY_READ(sc, MII_BMSR, &bmsr);
        PHY_READ(sc, MII_AMHPHY_SSR, &ssr);

        if (ssr & SSR_LS)
                mii->mii_media_status |= IFM_ACTIVE;

        PHY_READ(sc, MII_BMCR, &bmcr);
        if (bmcr & BMCR_ISO) {
                mii->mii_media_active |= IFM_NONE;
                mii->mii_media_status = 0;
                return;
        }

        if (bmcr & BMCR_LOOP)
                mii->mii_media_active |= IFM_LOOP;

        if (bmcr & BMCR_AUTOEN) {
                /*
                 * The media status bits are only valid if autonegotiation
                 * has completed (or it's disabled).
                 */
                if ((bmsr & BMSR_ACOMP) == 0) {
                        /* Erg, still trying, I guess... */
                        mii->mii_media_active |= IFM_NONE;
                        return;
                }

                if (ssr & SSR_S) {
                        /*
                         * This shouldn't really ever happen, since it's
                         * a 10BASE-T only PHY. But the bit exists, according
                         * to the documentation, so we pay attention to it.
                         */
                        mii->mii_media_active |= IFM_100_TX;
                } else
                        mii->mii_media_active |= IFM_10_T;
                if (ssr & SSR_FD)
                        mii->mii_media_active |= IFM_FDX;
                else
                        mii->mii_media_active |= IFM_HDX;
        } else
                mii->mii_media_active = ife->ifm_media;
}