/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2013 Ganbold Tsagaankhuu <ganbold@freebsd.org>
 * All rights reserved.
 *
 * 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.
 */

/* CPU configuration module for Allwinner A20 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/rman.h>
#include <sys/timeet.h>
#include <sys/timetc.h>
#include <sys/watchdog.h>
#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/intr.h>

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

#include <machine/bus.h>

#include "a20_cpu_cfg.h"

struct a20_cpu_cfg_softc {
        struct resource         *res;
        bus_space_tag_t         bst;
        bus_space_handle_t      bsh;
};

static struct a20_cpu_cfg_softc *a20_cpu_cfg_sc = NULL;

#define cpu_cfg_read_4(sc, reg)         \
        bus_space_read_4((sc)->bst, (sc)->bsh, (reg))
#define cpu_cfg_write_4(sc, reg, val)   \
        bus_space_write_4((sc)->bst, (sc)->bsh, (reg), (val))

static int
a20_cpu_cfg_probe(device_t dev)
{

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

        if (ofw_bus_is_compatible(dev, "allwinner,sun7i-cpu-cfg")) {
                device_set_desc(dev, "A20 CPU Configuration Module");
                return(BUS_PROBE_DEFAULT);
        }

        return (ENXIO);
}

static int
a20_cpu_cfg_attach(device_t dev)
{
        struct a20_cpu_cfg_softc *sc = device_get_softc(dev);
        int rid = 0;

        if (a20_cpu_cfg_sc)
                return (ENXIO);

        sc->res = bus_alloc_resource_any(dev, SYS_RES_MEMORY, &rid, RF_ACTIVE);
        if (!sc->res) {
                device_printf(dev, "could not allocate resource\n");
                return (ENXIO);
        }

        sc->bst = rman_get_bustag(sc->res);
        sc->bsh = rman_get_bushandle(sc->res);

        a20_cpu_cfg_sc = sc;

        return (0);
}

static device_method_t a20_cpu_cfg_methods[] = {
        DEVMETHOD(device_probe,         a20_cpu_cfg_probe),
        DEVMETHOD(device_attach,        a20_cpu_cfg_attach),
        { 0, 0 }
};

static driver_t a20_cpu_cfg_driver = {
        "a20_cpu_cfg",
        a20_cpu_cfg_methods,
        sizeof(struct a20_cpu_cfg_softc),
};

EARLY_DRIVER_MODULE(a20_cpu_cfg, simplebus, a20_cpu_cfg_driver, 0, 0,
    BUS_PASS_CPU + BUS_PASS_ORDER_FIRST);

uint64_t
a20_read_counter64(void)
{
        uint32_t lo, hi;

        /* Latch counter, wait for it to be ready to read. */
        cpu_cfg_write_4(a20_cpu_cfg_sc, OSC24M_CNT64_CTRL_REG, CNT64_RL_EN);
        while (cpu_cfg_read_4(a20_cpu_cfg_sc, OSC24M_CNT64_CTRL_REG) & CNT64_RL_EN)
                continue;

        hi = cpu_cfg_read_4(a20_cpu_cfg_sc, OSC24M_CNT64_HIGH_REG);
        lo = cpu_cfg_read_4(a20_cpu_cfg_sc, OSC24M_CNT64_LOW_REG);

        return (((uint64_t)hi << 32) | lo);
}