/*-
 * Copyright (c) 2012 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.
 */

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

#include <machine/bus.h>
#include <machine/intr.h>
#include <machine/machdep.h>

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

#include <dev/clk/clk.h>

#if defined(__aarch64__) || defined(__riscv)
#include "opt_soc.h"
#else
#include <arm/allwinner/aw_machdep.h>
#endif

/**
 * Timer registers addr
 *
 */
#define TIMER_IRQ_EN_REG        0x00
#define  TIMER_IRQ_ENABLE(x)    (1 << x)

#define TIMER_IRQ_STA_REG       0x04
#define  TIMER_IRQ_PENDING(x)   (1 << x)

/*
 * On A10, A13, A20 and A31/A31s 6 timers are available
 */
#define TIMER_CTRL_REG(x)               (0x10 + 0x10 * x)
#define  TIMER_CTRL_START               (1 << 0)
#define  TIMER_CTRL_AUTORELOAD          (1 << 1)
#define  TIMER_CTRL_CLKSRC_MASK         (3 << 2)
#define  TIMER_CTRL_OSC24M              (1 << 2)
#define  TIMER_CTRL_PRESCALAR_MASK      (0x7 << 4)
#define  TIMER_CTRL_PRESCALAR(x)        ((x - 1) << 4)
#define  TIMER_CTRL_MODE_MASK           (1 << 7)
#define  TIMER_CTRL_MODE_SINGLE         (1 << 7)
#define  TIMER_CTRL_MODE_CONTINUOUS     (0 << 7)
#define TIMER_INTV_REG(x)               (0x14 + 0x10 * x)
#define TIMER_CURV_REG(x)               (0x18 + 0x10 * x)

/* 64 bit counter, available in A10 and A13 */
#define CNT64_CTRL_REG          0xa0
#define  CNT64_CTRL_RL_EN       0x02 /* read latch enable */
#define CNT64_LO_REG            0xa4
#define CNT64_HI_REG            0xa8

#define SYS_TIMER_CLKSRC        24000000 /* clock source */

enum aw_timer_type {
        A10_TIMER = 1,
        A23_TIMER,
        D1_TIMER,
};

struct aw_timer_softc {
        device_t        sc_dev;
        struct resource *res[2];
        void            *sc_ih;         /* interrupt handler */
        uint32_t        sc_period;
        uint64_t        timer0_freq;
        struct eventtimer       et;
        enum aw_timer_type      type;
};

#define timer_read_4(sc, reg)   \
        bus_read_4(sc->res[AW_TIMER_MEMRES], reg)
#define timer_write_4(sc, reg, val)     \
        bus_write_4(sc->res[AW_TIMER_MEMRES], reg, val)

#if defined(__arm__)
static u_int    a10_timer_get_timecount(struct timecounter *);
static uint64_t a10_timer_read_counter64(struct aw_timer_softc *sc);
static void     a10_timer_timecounter_setup(struct aw_timer_softc *sc);
#endif

#if defined(__arm__) || defined(__riscv)
#define USE_EVENTTIMER
static void     aw_timer_eventtimer_setup(struct aw_timer_softc *sc);
static int      aw_timer_eventtimer_start(struct eventtimer *, sbintime_t first,
                    sbintime_t period);
static int      aw_timer_eventtimer_stop(struct eventtimer *);
#endif

#if defined(__aarch64__)
static void a23_timer_timecounter_setup(struct aw_timer_softc *sc);
static u_int a23_timer_get_timecount(struct timecounter *tc);
#endif

static int aw_timer_irq(void *);
static int aw_timer_probe(device_t);
static int aw_timer_attach(device_t);

#if defined(__arm__)
#define AW_TIMER_QUALITY        1000

static delay_func a10_timer_delay;

static struct timecounter a10_timer_timecounter = {
        .tc_name           = "aw_timer timer0",
        .tc_get_timecount  = a10_timer_get_timecount,
        .tc_counter_mask   = ~0u,
        .tc_frequency      = 0,
        .tc_quality        = AW_TIMER_QUALITY,
};
#endif

#if defined(__aarch64__)
/* We want it to be selected over the arm generic timecounter */
#define AW_TIMER_QUALITY        2000

static struct timecounter a23_timer_timecounter = {
        .tc_name           = "aw_timer timer0",
        .tc_get_timecount  = a23_timer_get_timecount,
        .tc_counter_mask   = ~0u,
        .tc_frequency      = 0,
        .tc_quality        = AW_TIMER_QUALITY,
};
#endif

#if defined(__riscv)
/* We want it to be selected over the generic RISC-V eventtimer */
#define AW_TIMER_QUALITY        2000
#endif

#define AW_TIMER_MEMRES         0
#define AW_TIMER_IRQRES         1

static struct resource_spec aw_timer_spec[] = {
        { SYS_RES_MEMORY,       0,      RF_ACTIVE },
        { SYS_RES_IRQ,          0,      RF_ACTIVE },
        { -1, 0 }
};

static struct ofw_compat_data compat_data[] = {
        {"allwinner,sun4i-a10-timer", A10_TIMER},
#if defined(__aarch64__)
        {"allwinner,sun8i-a23-timer", A23_TIMER},
#elif defined(__riscv)
        {"allwinner,sun20i-d1-timer", D1_TIMER},
#endif
        {NULL, 0},
};

static int
aw_timer_probe(device_t dev)
{
        if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
                return (ENXIO);

#if defined(__arm__)
        /* For SoC >= A10 we have the ARM Timecounter/Eventtimer */
        u_int soc_family = allwinner_soc_family();
        if (soc_family != ALLWINNERSOC_SUN4I &&
            soc_family != ALLWINNERSOC_SUN5I)
                return (ENXIO);
#endif

        device_set_desc(dev, "Allwinner timer");
        return (BUS_PROBE_DEFAULT);
}

static int
aw_timer_attach(device_t dev)
{
        struct aw_timer_softc *sc;
        clk_t clk;
        int err;

        sc = device_get_softc(dev);
        sc->type = ofw_bus_search_compatible(dev, compat_data)->ocd_data;

        if (bus_alloc_resources(dev, aw_timer_spec, sc->res)) {
                device_printf(dev, "could not allocate resources\n");
                return (ENXIO);
        }

        sc->sc_dev = dev;

        /* Setup and enable the timer interrupt */
        err = bus_setup_intr(dev, sc->res[AW_TIMER_IRQRES], INTR_TYPE_CLK,
            aw_timer_irq, NULL, sc, &sc->sc_ih);
        if (err != 0) {
                bus_release_resources(dev, aw_timer_spec, sc->res);
                device_printf(dev, "Unable to setup the clock irq handler, "
                    "err = %d\n", err);
                return (ENXIO);
        }

        if (clk_get_by_ofw_index(dev, 0, 0, &clk) != 0) {
                sc->timer0_freq = SYS_TIMER_CLKSRC;
        } else {
                if (clk_get_freq(clk, &sc->timer0_freq) != 0) {
                        device_printf(dev, "Cannot get clock source frequency\n");
                        return (ENXIO);
                }
        }

        if (bootverbose) {
                device_printf(sc->sc_dev, "clock: hz=%d stathz = %d\n", hz,
                    stathz);
        }

        /* Set up eventtimer (if applicable) */
#if defined(USE_EVENTTIMER)
        aw_timer_eventtimer_setup(sc);
#endif

        /* Set up timercounter (if applicable) */
#if defined(__arm__)
        a10_timer_timecounter_setup(sc);
#elif defined(__aarch64__)
        a23_timer_timecounter_setup(sc);
#endif

        return (0);
}

static int
aw_timer_irq(void *arg)
{
        struct aw_timer_softc *sc;
        uint32_t val;

        sc = (struct aw_timer_softc *)arg;

        /* Clear interrupt pending bit. */
        timer_write_4(sc, TIMER_IRQ_STA_REG, TIMER_IRQ_PENDING(0));

        val = timer_read_4(sc, TIMER_CTRL_REG(0));

        /*
         * Disabled autoreload and sc_period > 0 means 
         * timer_start was called with non NULL first value.
         * Now we will set periodic timer with the given period 
         * value.
         */
        if ((val & (1<<1)) == 0 && sc->sc_period > 0) {
                /* Update timer */
                timer_write_4(sc, TIMER_CURV_REG(0), sc->sc_period);

                /* Make periodic and enable */
                val |= TIMER_CTRL_AUTORELOAD | TIMER_CTRL_START;
                timer_write_4(sc, TIMER_CTRL_REG(0), val);
        }

        if (sc->et.et_active)
                sc->et.et_event_cb(&sc->et, sc->et.et_arg);

        return (FILTER_HANDLED);
}

/*
 * Event timer function for A10, A13, and D1.
 */
#if defined(USE_EVENTTIMER)
static void
aw_timer_eventtimer_setup(struct aw_timer_softc *sc)
{
        uint32_t val;

        /* Set clock source to OSC24M, 1 pre-division, continuous mode */
        val = timer_read_4(sc, TIMER_CTRL_REG(0));
        val &= ~TIMER_CTRL_PRESCALAR_MASK | ~TIMER_CTRL_MODE_MASK | ~TIMER_CTRL_CLKSRC_MASK;
        val |= TIMER_CTRL_PRESCALAR(1) | TIMER_CTRL_OSC24M;
        timer_write_4(sc, TIMER_CTRL_REG(0), val);

        /* Enable timer0 */
        val = timer_read_4(sc, TIMER_IRQ_EN_REG);
        val |= TIMER_IRQ_ENABLE(0);
        timer_write_4(sc, TIMER_IRQ_EN_REG, val);

        /* Set desired frequency in event timer and timecounter */
        sc->et.et_frequency = sc->timer0_freq;
        sc->et.et_name = "aw_timer Eventtimer";
        sc->et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERIODIC;
        sc->et.et_quality = AW_TIMER_QUALITY;
        sc->et.et_min_period = (0x00000005LLU << 32) / sc->et.et_frequency;
        sc->et.et_max_period = (0xfffffffeLLU << 32) / sc->et.et_frequency;
        sc->et.et_start = aw_timer_eventtimer_start;
        sc->et.et_stop = aw_timer_eventtimer_stop;
        sc->et.et_priv = sc;
        et_register(&sc->et);

        if (bootverbose) {
                device_printf(sc->sc_dev, "event timer clock frequency %ju\n",
                    sc->timer0_freq);
        }
}

static int
aw_timer_eventtimer_start(struct eventtimer *et, sbintime_t first,
    sbintime_t period)
{
        struct aw_timer_softc *sc;
        uint32_t count;
        uint32_t val;

        sc = (struct aw_timer_softc *)et->et_priv;

        if (period != 0)
                sc->sc_period = ((uint32_t)et->et_frequency * period) >> 32;
        else
                sc->sc_period = 0;
        if (first != 0)
                count = ((uint32_t)et->et_frequency * first) >> 32;
        else
                count = sc->sc_period;

        /* Update timer values */
        timer_write_4(sc, TIMER_INTV_REG(0), sc->sc_period);
        timer_write_4(sc, TIMER_CURV_REG(0), count);

        val = timer_read_4(sc, TIMER_CTRL_REG(0));
        if (period != 0) {
                /* periodic */
                val |= TIMER_CTRL_AUTORELOAD;
        } else {
                /* oneshot */
                val &= ~TIMER_CTRL_AUTORELOAD;
        }
        /* Enable timer0 */
        val |= TIMER_IRQ_ENABLE(0);
        timer_write_4(sc, TIMER_CTRL_REG(0), val);

        return (0);
}

static int
aw_timer_eventtimer_stop(struct eventtimer *et)
{
        struct aw_timer_softc *sc;
        uint32_t val;

        sc = (struct aw_timer_softc *)et->et_priv;

        /* Disable timer0 */
        val = timer_read_4(sc, TIMER_CTRL_REG(0));
        val &= ~TIMER_CTRL_START;
        timer_write_4(sc, TIMER_CTRL_REG(0), val);

        sc->sc_period = 0;

        return (0);
}
#endif /* USE_EVENTTIMER */

/*
 * Timecounter functions for A23 and above
 */

#if defined(__aarch64__)
static void
a23_timer_timecounter_setup(struct aw_timer_softc *sc)
{
        uint32_t val;

        /* Set clock source to OSC24M, 1 pre-division, continuous mode */
        val = timer_read_4(sc, TIMER_CTRL_REG(0));
        val &= ~TIMER_CTRL_PRESCALAR_MASK | ~TIMER_CTRL_MODE_MASK | ~TIMER_CTRL_CLKSRC_MASK;
        val |= TIMER_CTRL_PRESCALAR(1) | TIMER_CTRL_OSC24M;
        timer_write_4(sc, TIMER_CTRL_REG(0), val);

        /* Set reload value */
        timer_write_4(sc, TIMER_INTV_REG(0), ~0);
        val = timer_read_4(sc, TIMER_INTV_REG(0));

        /* Enable timer0 */
        val = timer_read_4(sc, TIMER_CTRL_REG(0));
        val |= TIMER_CTRL_AUTORELOAD | TIMER_CTRL_START;
        timer_write_4(sc, TIMER_CTRL_REG(0), val);

        val = timer_read_4(sc, TIMER_CURV_REG(0));

        a23_timer_timecounter.tc_priv = sc;
        a23_timer_timecounter.tc_frequency = sc->timer0_freq;
        tc_init(&a23_timer_timecounter);

        if (bootverbose) {
                device_printf(sc->sc_dev, "timecounter clock frequency %jd\n",
                    a23_timer_timecounter.tc_frequency);
        }
}

static u_int
a23_timer_get_timecount(struct timecounter *tc)
{
        struct aw_timer_softc *sc;
        uint32_t val;

        sc = (struct aw_timer_softc *)tc->tc_priv;
        if (sc == NULL)
                return (0);

        val = timer_read_4(sc, TIMER_CURV_REG(0));
        /* Counter count backwards */
        return (~0u - val);
}
#endif /* __aarch64__ */

/*
 * Timecounter functions for A10 and A13, using the 64 bits counter
 */

#if defined(__arm__)
static uint64_t
a10_timer_read_counter64(struct aw_timer_softc *sc)
{
        uint32_t lo, hi;

        /* Latch counter, wait for it to be ready to read. */
        timer_write_4(sc, CNT64_CTRL_REG, CNT64_CTRL_RL_EN);
        while (timer_read_4(sc, CNT64_CTRL_REG) & CNT64_CTRL_RL_EN)
                continue;

        hi = timer_read_4(sc, CNT64_HI_REG);
        lo = timer_read_4(sc, CNT64_LO_REG);

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

static void
a10_timer_delay(int usec, void *arg)
{
        struct aw_timer_softc *sc = arg;
        uint64_t end, now;

        now = a10_timer_read_counter64(sc);
        end = now + (sc->timer0_freq / 1000000) * (usec + 1);

        while (now < end)
                now = a10_timer_read_counter64(sc);
}

static u_int
a10_timer_get_timecount(struct timecounter *tc)
{
        if (tc->tc_priv == NULL)
                return (0);

        return ((u_int)a10_timer_read_counter64(tc->tc_priv));
}

static void
a10_timer_timecounter_setup(struct aw_timer_softc *sc)
{
        arm_set_delay(a10_timer_delay, sc);
        a10_timer_timecounter.tc_priv = sc;
        a10_timer_timecounter.tc_frequency = sc->timer0_freq;
        tc_init(&a10_timer_timecounter);

        if (bootverbose) {
                device_printf(sc->sc_dev, "timecounter clock frequency %jd\n",
                    a10_timer_timecounter.tc_frequency);
        }
}
#endif /* __arm__ */

static device_method_t aw_timer_methods[] = {
        DEVMETHOD(device_probe,         aw_timer_probe),
        DEVMETHOD(device_attach,        aw_timer_attach),

        DEVMETHOD_END
};

static driver_t aw_timer_driver = {
        "aw_timer",
        aw_timer_methods,
        sizeof(struct aw_timer_softc),
};

EARLY_DRIVER_MODULE(aw_timer, simplebus, aw_timer_driver, 0, 0,
    BUS_PASS_TIMER + BUS_PASS_ORDER_MIDDLE);