/*-
 * Copyright (c) 2015 The FreeBSD Foundation
 *
 * This software was developed by Semihalf under
 * the sponsorship of the FreeBSD Foundation.
 *
 * 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 AUTHOR 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 AUTHOR 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.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/resource.h>
#include <sys/rman.h>
#include <sys/socket.h>
#include <sys/queue.h>

#include <machine/bus.h>
#include <machine/resource.h>

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

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

#include "thunder_mdio_var.h"

#include "lmac_if.h"
#include "miibus_if.h"

#define REG_BASE_RID    0

#define SMI_CMD                         0x00
#define  SMI_CMD_PHY_REG_ADR_SHIFT      (0)
#define  SMI_CMD_PHY_REG_ADR_MASK       (0x1FUL << SMI_CMD_PHY_REG_ADR_SHIFT)
#define  SMI_CMD_PHY_ADR_SHIFT          (8)
#define  SMI_CMD_PHY_ADR_MASK           (0x1FUL << SMI_CMD_PHY_ADR_SHIFT)
#define  SMI_CMD_PHY_OP_MASK            (0x3UL << 16)
#define  SMI_CMD_PHY_OP_C22_READ        (0x1UL << 16)
#define  SMI_CMD_PHY_OP_C22_WRITE       (0x0UL << 16)
#define  SMI_CMD_PHY_OP_C45_READ        (0x3UL << 16)
#define  SMI_CMD_PHY_OP_C45_WRITE       (0x1UL << 16)
#define  SMI_CMD_PHY_OP_C45_ADDR        (0x0UL << 16)

#define SMI_WR_DAT                      0x08
#define  SMI_WR_DAT_PENDING             (1UL << 17)
#define  SMI_WR_DAT_VAL                 (1UL << 16)
#define  SMI_WR_DAT_DAT_MASK            (0xFFFFUL << 0)

#define SMI_RD_DAT                      0x10
#define  SMI_RD_DAT_PENDING             (1UL << 17)
#define  SMI_RD_DAT_VAL                 (1UL << 16)
#define  SMI_RD_DAT_DAT_MASK            (0xFFFFUL << 0)

#define SMI_CLK                         0x18
#define  SMI_CLK_PREAMBLE               (1UL << 12)
#define  SMI_CLK_MODE                   (1UL << 24)

#define SMI_EN                          0x20
#define  SMI_EN_EN                      (1UL << 0)      /* Enable interface */

#define SMI_DRV_CTL                     0x28

static int thunder_mdio_detach(device_t);

static int thunder_mdio_read(device_t, int, int);
static int thunder_mdio_write(device_t, int, int, int);

static int thunder_ifmedia_change_stub(if_t);
static void thunder_ifmedia_status_stub(if_t, struct ifmediareq *);

static int thunder_mdio_media_status(device_t, int, int *, int *, int *);
static int thunder_mdio_media_change(device_t, int, int, int, int);
static int thunder_mdio_phy_connect(device_t, int, int);
static int thunder_mdio_phy_disconnect(device_t, int, int);

static device_method_t thunder_mdio_methods[] = {
        /* Device interface */
        DEVMETHOD(device_detach,        thunder_mdio_detach),
        /* LMAC interface */
        DEVMETHOD(lmac_media_status,    thunder_mdio_media_status),
        DEVMETHOD(lmac_media_change,    thunder_mdio_media_change),
        DEVMETHOD(lmac_phy_connect,     thunder_mdio_phy_connect),
        DEVMETHOD(lmac_phy_disconnect,  thunder_mdio_phy_disconnect),
        /* MII interface */
        DEVMETHOD(miibus_readreg,       thunder_mdio_read),
        DEVMETHOD(miibus_writereg,      thunder_mdio_write),

        /* End */
        DEVMETHOD_END
};

DEFINE_CLASS_0(thunder_mdio, thunder_mdio_driver, thunder_mdio_methods,
    sizeof(struct thunder_mdio_softc));

DRIVER_MODULE(miibus, thunder_mdio, miibus_driver, 0, 0);
MODULE_VERSION(thunder_mdio, 1);
MODULE_DEPEND(thunder_mdio, ether, 1, 1, 1);
MODULE_DEPEND(thunder_mdio, miibus, 1, 1, 1);
MODULE_DEPEND(thunder_mdio, mrmlbus, 1, 1, 1);

MALLOC_DEFINE(M_THUNDER_MDIO, "ThunderX MDIO",
    "Cavium ThunderX MDIO dynamic memory");

#define MDIO_LOCK_INIT(sc, name)                        \
    mtx_init(&(sc)->mtx, name, NULL, MTX_DEF)

#define MDIO_LOCK_DESTROY(sc)                           \
    mtx_destroy(&(sc)->mtx)

#define MDIO_LOCK(sc)   mtx_lock(&(sc)->mtx)
#define MDIO_UNLOCK(sc) mtx_unlock(&(sc)->mtx)

#define MDIO_LOCK_ASSERT(sc)                            \
    mtx_assert(&(sc)->mtx, MA_OWNED)

#define mdio_reg_read(sc, reg)                          \
    bus_read_8((sc)->reg_base, (reg))

#define mdio_reg_write(sc, reg, val)                    \
    bus_write_8((sc)->reg_base, (reg), (val))

int
thunder_mdio_attach(device_t dev)
{
        struct thunder_mdio_softc *sc;
        int rid;

        sc = device_get_softc(dev);
        sc->dev = dev;

        /* Allocate memory resources */
        rid = REG_BASE_RID;
        sc->reg_base = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid,
            RF_ACTIVE);
        if (sc->reg_base == NULL) {
                device_printf(dev, "Could not allocate memory\n");
                return (ENXIO);
        }

        TAILQ_INIT(&sc->phy_desc_head);
        MDIO_LOCK_INIT(sc, "ThunderX MDIO lock");

        /* Enable SMI/MDIO interface */
        mdio_reg_write(sc, SMI_EN, SMI_EN_EN);

        return (0);
}

static int
thunder_mdio_detach(device_t dev)
{
        struct thunder_mdio_softc *sc;

        sc = device_get_softc(dev);

        if (sc->reg_base != NULL) {
                bus_release_resource(dev, SYS_RES_MEMORY, REG_BASE_RID,
                    sc->reg_base);
        }

        return (0);
}

static __inline void
thunder_mdio_set_mode(struct thunder_mdio_softc *sc,
    enum thunder_mdio_mode mode)
{
        uint64_t smi_clk;

        if (sc->mode == mode)
                return;

        /* Set mode, IEEE CLAUSE 22 or IEEE CAUSE 45 */
        smi_clk = mdio_reg_read(sc, SMI_CLK);
        if (mode == MODE_IEEE_C22)
                smi_clk &= ~SMI_CLK_MODE;
        else
                smi_clk |= SMI_CLK_MODE;
        /* Enable sending 32 bit preable on SMI transactions */
        smi_clk |= SMI_CLK_PREAMBLE;
        /* Saved settings */
        mdio_reg_write(sc, SMI_CLK, smi_clk);
        sc->mode = mode;
}

static int
thunder_mdio_c45_addr(struct thunder_mdio_softc *sc, int phy, int reg)
{
        uint64_t smi_cmd, smi_wr_dat;
        ssize_t timeout;

        thunder_mdio_set_mode(sc, MODE_IEEE_C45);

        /* Prepare data for transmission */
        mdio_reg_write(sc, SMI_WR_DAT, reg & SMI_WR_DAT_DAT_MASK);
        /*
         * Assemble command
         */
        smi_cmd = 0;
        /* Set opcode */
        smi_cmd |= SMI_CMD_PHY_OP_C45_WRITE;

        /* Set PHY address */
        smi_cmd |= ((phy << SMI_CMD_PHY_ADR_SHIFT) & SMI_CMD_PHY_ADR_MASK);
        /* Set PHY register offset */
        smi_cmd |= ((reg << SMI_CMD_PHY_REG_ADR_SHIFT) &
            SMI_CMD_PHY_REG_ADR_MASK);

        mdio_reg_write(sc, SMI_CMD, smi_cmd);
        for (timeout = 1000; timeout > 0; timeout--) {
                smi_wr_dat = mdio_reg_read(sc, SMI_WR_DAT);
                if (smi_wr_dat & SMI_WR_DAT_PENDING)
                        DELAY(1000);
                else
                        break;
        }

        if (timeout <= 0)
                return (EIO);
        else {
                /* Return 0 on success */
                return (0);
        }
}

static int
thunder_mdio_read(device_t dev, int phy, int reg)
{
        struct thunder_mdio_softc *sc;
        uint64_t smi_cmd, smi_rd_dat;
        ssize_t timeout;
        int err;

        sc = device_get_softc(dev);

        /* XXX Always C22 - for <= 1Gbps only */
        thunder_mdio_set_mode(sc, MODE_IEEE_C22);

        /*
         * Assemble command
         */
        smi_cmd = 0;
        /* Set opcode */
        if (sc->mode == MODE_IEEE_C22)
                smi_cmd |= SMI_CMD_PHY_OP_C22_READ;
        else {
                smi_cmd |= SMI_CMD_PHY_OP_C45_READ;
                err = thunder_mdio_c45_addr(sc, phy, reg);
                if (err != 0)
                        return (err);

                reg = (reg >> 16) & 0x1F;
        }

        /* Set PHY address */
        smi_cmd |= ((phy << SMI_CMD_PHY_ADR_SHIFT) & SMI_CMD_PHY_ADR_MASK);
        /* Set PHY register offset */
        smi_cmd |= ((reg << SMI_CMD_PHY_REG_ADR_SHIFT) &
            SMI_CMD_PHY_REG_ADR_MASK);

        mdio_reg_write(sc, SMI_CMD, smi_cmd);
        for (timeout = 1000; timeout > 0; timeout--) {
                smi_rd_dat = mdio_reg_read(sc, SMI_RD_DAT);
                if (smi_rd_dat & SMI_RD_DAT_PENDING)
                        DELAY(1000);
                else
                        break;
        }

        if (smi_rd_dat & SMI_RD_DAT_VAL)
                return (smi_rd_dat & SMI_RD_DAT_DAT_MASK);
        else {
                /* Return 0 on error */
                return (0);
        }
}

static int
thunder_mdio_write(device_t dev, int phy, int reg, int data)
{
        struct thunder_mdio_softc *sc;
        uint64_t smi_cmd, smi_wr_dat;
        ssize_t timeout;

        sc = device_get_softc(dev);

        /* XXX Always C22 - for <= 1Gbps only */
        thunder_mdio_set_mode(sc, MODE_IEEE_C22);

        /* Prepare data for transmission */
        mdio_reg_write(sc, SMI_WR_DAT, data & SMI_WR_DAT_DAT_MASK);
        /*
         * Assemble command
         */
        smi_cmd = 0;
        /* Set opcode */
        if (sc->mode == MODE_IEEE_C22)
                smi_cmd |= SMI_CMD_PHY_OP_C22_WRITE;
        else
                smi_cmd |= SMI_CMD_PHY_OP_C45_WRITE;

        /* Set PHY address */
        smi_cmd |= ((phy << SMI_CMD_PHY_ADR_SHIFT) & SMI_CMD_PHY_ADR_MASK);
        /* Set PHY register offset */
        smi_cmd |= ((reg << SMI_CMD_PHY_REG_ADR_SHIFT) &
            SMI_CMD_PHY_REG_ADR_MASK);

        mdio_reg_write(sc, SMI_CMD, smi_cmd);
        for (timeout = 1000; timeout > 0; timeout--) {
                smi_wr_dat = mdio_reg_read(sc, SMI_WR_DAT);
                if (smi_wr_dat & SMI_WR_DAT_PENDING)
                        DELAY(1000);
                else
                        break;
        }

        if (timeout <= 0)
                return (EIO);
        else {
                /* Return 0 on success */
                return (0);
        }
}

static int
thunder_ifmedia_change_stub(if_t ifp __unused)
{
        /* Will never be called by if_media */
        return (0);
}

static void
thunder_ifmedia_status_stub(if_t ifp __unused, struct ifmediareq
    *ifmr __unused)
{
        /* Will never be called by if_media */
}

static __inline struct phy_desc *
get_phy_desc(struct thunder_mdio_softc *sc, int lmacid)
{
        struct phy_desc *pd = NULL;

        MDIO_LOCK_ASSERT(sc);
        TAILQ_FOREACH(pd, &sc->phy_desc_head, phy_desc_list) {
                if (pd->lmacid == lmacid)
                        break;
        }

        return (pd);
}
static int
thunder_mdio_media_status(device_t dev, int lmacid, int *link, int *duplex,
    int *speed)
{
        struct thunder_mdio_softc *sc;
        struct mii_data *mii_sc;
        struct phy_desc *pd;

        sc = device_get_softc(dev);

        MDIO_LOCK(sc);
        pd = get_phy_desc(sc, lmacid);
        if (pd == NULL) {
                /* Panic when invariants are enabled, fail otherwise. */
                KASSERT(0, ("%s: no PHY descriptor for LMAC%d",
                    __func__, lmacid));
                MDIO_UNLOCK(sc);
                return (ENXIO);
        }
        mii_sc = device_get_softc(pd->miibus);

        mii_tick(mii_sc);
        if ((mii_sc->mii_media_status & (IFM_ACTIVE | IFM_AVALID)) ==
            (IFM_ACTIVE | IFM_AVALID)) {
                /* Link is up */
                *link = 1;
        } else
                *link = 0;

        switch (IFM_SUBTYPE(mii_sc->mii_media_active)) {
        case IFM_10_T:
                *speed = 10;
                break;
        case IFM_100_TX:
                *speed = 100;
                break;
        case IFM_1000_T:
                *speed = 1000;
                break;
        default:
                /* IFM_NONE */
                *speed = 0;
        }

        if ((IFM_OPTIONS(mii_sc->mii_media_active) & IFM_FDX) != 0)
                *duplex = 1;
        else
                *duplex = 0;

        MDIO_UNLOCK(sc);

        return (0);
}

static int
thunder_mdio_media_change(device_t dev, int lmacid, int link, int duplex,
    int speed)
{

        return (EIO);
}

static int
thunder_mdio_phy_connect(device_t dev, int lmacid, int phy)
{
        struct thunder_mdio_softc *sc;
        struct phy_desc *pd;
        int err;

        sc = device_get_softc(dev);

        MDIO_LOCK(sc);
        pd = get_phy_desc(sc, lmacid);
        MDIO_UNLOCK(sc);
        if (pd == NULL) {
                pd = malloc(sizeof(*pd), M_THUNDER_MDIO, (M_NOWAIT | M_ZERO));
                if (pd == NULL)
                        return (ENOMEM);
                pd->ifp = if_alloc(IFT_ETHER);
                pd->lmacid = lmacid;
        }

        err = mii_attach(dev, &pd->miibus, pd->ifp,
            thunder_ifmedia_change_stub, thunder_ifmedia_status_stub,
            BMSR_DEFCAPMASK, phy, MII_OFFSET_ANY, 0);

        if (err != 0) {
                device_printf(dev, "Could not attach PHY%d\n", phy);
                if_free(pd->ifp);
                free(pd, M_THUNDER_MDIO);
                return (ENXIO);
        }

        MDIO_LOCK(sc);
        TAILQ_INSERT_TAIL(&sc->phy_desc_head, pd, phy_desc_list);
        MDIO_UNLOCK(sc);

        return (0);
}

static int
thunder_mdio_phy_disconnect(device_t dev, int lmacid, int phy)
{
        struct thunder_mdio_softc *sc;
        struct phy_desc *pd;

        sc = device_get_softc(dev);
        MDIO_LOCK(sc);

        pd = get_phy_desc(sc, lmacid);
        if (pd == NULL) {
                MDIO_UNLOCK(sc);
                return (EINVAL);
        }

        /* Remove this PHY descriptor from the list */
        TAILQ_REMOVE(&sc->phy_desc_head, pd, phy_desc_list);

        /* Detach miibus */
        bus_generic_detach(dev);
        /* Free fake ifnet */
        if_free(pd->ifp);
        /* Free memory under phy descriptor */
        free(pd, M_THUNDER_MDIO);
        MDIO_UNLOCK(sc);

        return (0);
}