/*      $NetBSD: i80321_timer.c,v 1.22 2018/07/12 10:46:42 maxv Exp $ */

/*
 * Copyright (c) 2001, 2002 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.
 */

/*
 * Timer/clock support for the Intel i80321 I/O processor.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: i80321_timer.c,v 1.22 2018/07/12 10:46:42 maxv Exp $");

#include "opt_i80321.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/time.h>
#include <sys/timetc.h>

#include <dev/clock_subr.h>

#include <sys/bus.h>
#include <arm/cpufunc.h>

#include <arm/xscale/i80321reg.h>
#include <arm/xscale/i80321var.h>

void    (*i80321_hardclock_hook)(void);

#ifndef COUNTS_PER_SEC
#define COUNTS_PER_SEC          200000000       /* 200MHz */
#endif
#define COUNTS_PER_USEC         (COUNTS_PER_SEC / 1000000)

static void tmr1_tc_init(void);

static void *clock_ih;

static uint32_t counts_per_hz;

int     clockhandler(void *);

__unused static inline uint32_t
tmr0_read(void)
{
        uint32_t rv;

        __asm volatile("mrc p6, 0, %0, c0, c1, 0"
                : "=r" (rv));
        return (rv);
}

static inline void
tmr0_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c0, c1, 0"
                :
                : "r" (val));
}

static inline uint32_t
tcr0_read(void)
{
        uint32_t rv;

        __asm volatile("mrc p6, 0, %0, c2, c1, 0"
                : "=r" (rv));
        return (rv);
}

static inline void
tcr0_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c2, c1, 0"
                :
                : "r" (val));
}

static inline void
trr0_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c4, c1, 0"
                :
                : "r" (val));
}

__unused static inline uint32_t
tmr1_read(void)
{
        uint32_t rv;

        __asm volatile("mrc p6, 0, %0, c1, c1, 0"
                : "=r" (rv));
        return (rv);
}

static inline void
tmr1_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c1, c1, 0"
                :
                : "r" (val));
}

static inline uint32_t
tcr1_read(void)
{
        uint32_t rv;

        __asm volatile("mrc p6, 0, %0, c3, c1, 0"
                : "=r" (rv));
        return (rv);
}

static inline void
tcr1_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c3, c1, 0"
                :
                : "r" (val));
}

static inline void
trr1_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c5, c1, 0"
                :
                : "r" (val));
}

static inline void
tisr_write(uint32_t val)
{

        __asm volatile("mcr p6, 0, %0, c6, c1, 0"
                :
                : "r" (val));
}

/*
 * i80321_calibrate_delay:
 *
 *      Calibrate the delay loop.
 */
void
i80321_calibrate_delay(void)
{

        /*
         * Just use hz=100 for now -- we'll adjust it, if necessary,
         * in cpu_initclocks().
         */
        counts_per_hz = COUNTS_PER_SEC / 100;

        tmr0_write(0);                  /* stop timer */
        tisr_write(TISR_TMR0);          /* clear interrupt */
        trr0_write(counts_per_hz);      /* reload value */
        tcr0_write(counts_per_hz);      /* current value */

        tmr0_write(TMRx_ENABLE|TMRx_RELOAD|TMRx_CSEL_CORE);
}

/*
 * cpu_initclocks:
 *
 *      Initialize the clock and get them going.
 */
void
cpu_initclocks(void)
{
        u_int oldirqstate;

        if (hz < 50 || COUNTS_PER_SEC % hz) {
                aprint_error("Cannot get %d Hz clock; using 100 Hz\n", hz);
                hz = 100;
        }

        /*
         * We only have one timer available; stathz and profhz are
         * always left as 0 (the upper-layer clock code deals with
         * this situation).
         */
        if (stathz != 0)
                aprint_error("Cannot get %d Hz statclock\n", stathz);
        stathz = 0;

        if (profhz != 0)
                aprint_error("Cannot get %d Hz profclock\n", profhz);
        profhz = 0;

        /* Report the clock frequency. */
        aprint_normal("clock: hz=%d stathz=%d profhz=%d\n", hz, stathz, profhz);

        oldirqstate = disable_interrupts(I32_bit);

        /* Hook up the clock interrupt handler. */
        clock_ih = i80321_intr_establish(ICU_INT_TMR0, IPL_CLOCK,
            clockhandler, NULL);
        if (clock_ih == NULL)
                panic("cpu_initclocks: unable to register timer interrupt");

        /* Set up the new clock parameters. */

        tmr0_write(0);                  /* stop timer */
        tisr_write(TISR_TMR0);          /* clear interrupt */

        counts_per_hz = COUNTS_PER_SEC / hz;

        trr0_write(counts_per_hz);      /* reload value */
        tcr0_write(counts_per_hz);      /* current value */

        tmr0_write(TMRx_ENABLE|TMRx_RELOAD|TMRx_CSEL_CORE);

        restore_interrupts(oldirqstate);

        tmr1_tc_init();
}

/*
 * setstatclockrate:
 *
 *      Set the rate of the statistics clock.
 *
 *      We assume that hz is either stathz or profhz, and that neither
 *      will change after being set by cpu_initclocks().  We could
 *      recalculate the intervals here, but that would be a pain.
 */
void
setstatclockrate(int newhz)
{

        /*
         * XXX Use TMR1?
         */
}

static inline uint32_t
tmr1_tc_get(struct timecounter *tch)
{
        return (~tcr1_read());
}

void
tmr1_tc_init(void)
{
        static struct timecounter tmr1_tc = {
                .tc_get_timecount = tmr1_tc_get,
                .tc_frequency = COUNTS_PER_SEC,
                .tc_counter_mask = ~0,
                .tc_name = "tmr1_count",
                .tc_quality = 100,
        };

        /* program the tc */
        trr1_write(~0); /* reload value */
        tcr1_write(~0); /* current value */

        tmr1_write(TMRx_ENABLE|TMRx_RELOAD|TMRx_CSEL_CORE);


        trr1_write(~0);
        tc_init(&tmr1_tc);
}

/*
 * delay:
 *
 *      Delay for at least N microseconds.
 */
void
delay(u_int n)
{
        uint32_t cur, last, delta, usecs;

        /*
         * This works by polling the timer and counting the
         * number of microseconds that go by.
         */
        last = tcr0_read();
        delta = usecs = 0;

        while (n > usecs) {
                cur = tcr0_read();

                /* Check to see if the timer has wrapped around. */
                if (last < cur)
                        delta += (last + (counts_per_hz - cur));
                else
                        delta += (last - cur);

                last = cur;

                if (delta >= COUNTS_PER_USEC) {
                        usecs += delta / COUNTS_PER_USEC;
                        delta %= COUNTS_PER_USEC;
                }
        }
}

/*
 * clockhandler:
 *
 *      Handle the hardclock interrupt.
 */
int
clockhandler(void *arg)
{
        struct clockframe *frame = arg;

        tisr_write(TISR_TMR0);

        hardclock(frame);

        if (i80321_hardclock_hook != NULL)
                (*i80321_hardclock_hook)();

        return (1);
}