/*
 * Copyright (c) 2026 Justin Hibbits
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

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

#include <machine/bus.h>

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

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

#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>

#include "fman.h"
#include "miibus_if.h"
#include "mdio_if.h"

#define MDIO_LOCK()     mtx_lock(&sc->sc_lock)
#define MDIO_UNLOCK()   mtx_unlock(&sc->sc_lock)
#define MDIO_WRITE4(sc, r, v) \
        bus_write_4(sc->sc_res, r, v)
#define MDIO_READ4(sc, r) \
        bus_read_4(sc->sc_res, r)

#define MDIO_CFG                0x30
#define   CFG_ENC45               0x00000040
#define MDIO_STAT               0x30
#define   STAT_BUSY               0x80000000
#define   STAT_MDIO_RD_ER         0x00000002
#define MDIO_CTL                0x34
#define   CTL_READ                0x00008000
#define MDIO_DATA               0x38
#define MDIO_ADDR               0x3c

static int xmdio_fdt_probe(device_t dev);
static int xmdio_fdt_attach(device_t dev);
static int xmdio_detach(device_t dev);
static int xmdio_miibus_readreg(device_t dev, int phy, int reg);
static int xmdio_miibus_writereg(device_t dev, int phy, int reg, int value);
static int xmdio_mdio_readextreg(device_t dev, int phy, int devad, int reg);
static int xmdio_mdio_writeextreg(device_t dev, int phy, int devad, int reg,
    int val);

struct xmdio_softc {
        struct mtx sc_lock;
        struct resource *sc_res;
};

static struct ofw_compat_data mdio_compat_data[] = {
        {"fsl,fman-memac-mdio", 0},
        {"fsl,fman-xmdio", 0},
        {NULL, 0}
};

static device_method_t xmdio_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         xmdio_fdt_probe),
        DEVMETHOD(device_attach,        xmdio_fdt_attach),
        DEVMETHOD(device_detach,        xmdio_detach),
        DEVMETHOD(bus_add_child,        bus_generic_add_child),

        /* MII interface */
        DEVMETHOD(miibus_readreg,       xmdio_miibus_readreg),
        DEVMETHOD(miibus_writereg,      xmdio_miibus_writereg),

        /* MDIO interface */
        DEVMETHOD(mdio_readreg,         xmdio_miibus_readreg),
        DEVMETHOD(mdio_writereg,        xmdio_miibus_writereg),
        DEVMETHOD(mdio_readextreg,      xmdio_mdio_readextreg),
        DEVMETHOD(mdio_writeextreg,     xmdio_mdio_writeextreg),

        DEVMETHOD_END
};

static driver_t xmdio_driver = {
        "xmdio",
        xmdio_methods,
        sizeof(struct xmdio_softc),
};

EARLY_DRIVER_MODULE(xmdio, fman, xmdio_driver, 0, 0,
    BUS_PASS_SUPPORTDEV);
DRIVER_MODULE(miibus, xmdio, miibus_driver, 0, 0);
DRIVER_MODULE(mdio, xmdio, mdio_driver, 0, 0);
MODULE_DEPEND(xmdio, miibus, 1, 1, 1);

static int
xmdio_fdt_probe(device_t dev)
{

        if (!ofw_bus_status_okay(dev))
                return (ENXIO);

        if (!ofw_bus_search_compatible(dev, mdio_compat_data)->ocd_str)
                return (ENXIO);

        device_set_desc(dev, "Freescale XGMAC MDIO");

        return (BUS_PROBE_DEFAULT);
}

static int
xmdio_fdt_attach(device_t dev)
{
        struct xmdio_softc *sc;

        sc = device_get_softc(dev);

        sc->sc_res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, 0, RF_ACTIVE);

        OF_device_register_xref(OF_xref_from_node(ofw_bus_get_node(dev)), dev);

        mtx_init(&sc->sc_lock, device_get_nameunit(dev), "XMDIO lock",
            MTX_DEF);

        return (0);
}

static int
xmdio_detach(device_t dev)
{
        struct xmdio_softc *sc;

        sc = device_get_softc(dev);

        mtx_destroy(&sc->sc_lock);

        return (0);
}

static void
set_clause45(struct xmdio_softc *sc)
{
        uint32_t reg;

        reg = MDIO_READ4(sc, MDIO_CFG);
        MDIO_WRITE4(sc, MDIO_CFG, reg | CFG_ENC45);
}

static void
set_clause22(struct xmdio_softc *sc)
{
        uint32_t reg;

        reg = MDIO_READ4(sc, MDIO_CFG);
        MDIO_WRITE4(sc, MDIO_CFG, reg & ~CFG_ENC45);
}

static int
xmdio_wait_no_busy(struct xmdio_softc *sc)
{
        uint32_t count, val;

        for (count = 1000; count > 0; count--) {
                val = MDIO_READ4(sc, MDIO_CFG);
                if ((val & STAT_BUSY) == 0)
                        break;
                DELAY(1);
        }

        if (count == 0)
                return (0xffff);

        return (0);
}

int
xmdio_miibus_readreg(device_t dev, int phy, int reg)
{
        struct xmdio_softc *sc;
        int                  rv;
        uint32_t ctl;

        sc = device_get_softc(dev);

        MDIO_LOCK();

        set_clause22(sc);
        ctl = (phy << 5) | reg;
        MDIO_WRITE4(sc, MDIO_CTL, ctl | CTL_READ);

        MDIO_READ4(sc, MDIO_CTL);

        if (xmdio_wait_no_busy(sc))
                rv = 0xffff;
        else
                rv = MDIO_READ4(sc, MDIO_DATA);

        MDIO_WRITE4(sc, MDIO_CTL, 0);
        MDIO_UNLOCK();

        return (rv);
}

int
xmdio_miibus_writereg(device_t dev, int phy, int reg, int value)
{
        struct xmdio_softc *sc;

        sc = device_get_softc(dev);

        MDIO_LOCK();
        set_clause22(sc);
        /* Stop the MII management read cycle */
        MDIO_WRITE4(sc, MDIO_CTL, (phy << 5) | reg);

        MDIO_WRITE4(sc, MDIO_DATA, value);

        /* Wait till MII management write is complete */
        xmdio_wait_no_busy(sc);
        MDIO_UNLOCK();

        return (0);
}

static int
xmdio_mdio_readextreg(device_t dev, int phy, int devad, int reg)
{
        struct xmdio_softc *sc;
        int                  rv;
        uint32_t ctl;

        sc = device_get_softc(dev);

        MDIO_LOCK();

        set_clause45(sc);
        ctl = (phy << 5) | devad;
        MDIO_WRITE4(sc, MDIO_CTL, ctl);
        MDIO_WRITE4(sc, MDIO_ADDR, reg);
        xmdio_wait_no_busy(sc);
        MDIO_WRITE4(sc, MDIO_CTL, ctl | CTL_READ);
        MDIO_READ4(sc, MDIO_CTL);

        xmdio_wait_no_busy(sc);

        if (MDIO_READ4(sc, MDIO_STAT) & STAT_MDIO_RD_ER)
                rv = 0xffff;
        else
                rv = MDIO_READ4(sc, MDIO_DATA);

        MDIO_WRITE4(sc, MDIO_CTL, 0);
        MDIO_UNLOCK();

        return (rv);
}

static int
xmdio_mdio_writeextreg(device_t dev, int phy, int devad, int reg, int val)
{
        struct xmdio_softc *sc;

        sc = device_get_softc(dev);

        MDIO_LOCK();
        set_clause45(sc);
        /* Stop the MII management read cycle */
        MDIO_WRITE4(sc, MDIO_CTL, (phy << 5) | devad);

        MDIO_WRITE4(sc, MDIO_DATA, val);

        /* Wait till MII management write is complete */
        xmdio_wait_no_busy(sc);
        MDIO_UNLOCK();

        return (0);
}