/*-
 * Copyright (c) 2015-2017 Ruslan Bukin <br@bsdpad.com>
 * All rights reserved.
 *
 * Portions of this software were developed by SRI International and the
 * University of Cambridge Computer Laboratory under DARPA/AFRL contract
 * FA8750-10-C-0237 ("CTSRD"), as part of the DARPA CRASH research programme.
 *
 * Portions of this software were developed by the University of Cambridge
 * Computer Laboratory as part of the CTSRD Project, with support from the
 * UK Higher Education Innovation Fund (HEIF).
 *
 * 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/kdb.h>
#include <sys/kernel.h>
#include <sys/priv.h>
#include <sys/systm.h>
#include <sys/types.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/consio.h>
#include <sys/tty.h>
#include <sys/bus.h>
#include <sys/module.h>
#include <sys/rman.h>

#include <dev/ofw/openfirm.h>
#include <ddb/ddb.h>

#include <vm/vm.h>
#include <vm/pmap.h>

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

#include <machine/bus.h>
#include <machine/cpu.h>
#include <machine/intr.h>
#include <machine/asm.h>
#include <machine/trap.h>
#include <machine/vmparam.h>
#include <machine/sbi.h>

/* bus softc */
struct rcons_softc {
        struct resource         *res[1];
        void                    *ihl[1];
        device_t                dev;
};

/* CN Console interface */

static tsw_outwakeup_t riscvtty_outwakeup;

static struct ttydevsw riscv_ttydevsw = {
        .tsw_flags      = TF_NOPREFIX,
        .tsw_outwakeup  = riscvtty_outwakeup,
};

static int                      polltime;
static struct callout           riscv_callout;
static struct tty               *tp = NULL;

#if defined(KDB)
static int                      alt_break_state;
#endif

static void     riscv_timeout(void *);

static cn_probe_t       riscv_cnprobe;
static cn_init_t        riscv_cninit;
static cn_term_t        riscv_cnterm;
static cn_getc_t        riscv_cngetc;
static cn_putc_t        riscv_cnputc;
static cn_grab_t        riscv_cngrab;
static cn_ungrab_t      riscv_cnungrab;

CONSOLE_DRIVER(riscv);

#define MAX_BURST_LEN           1

static void
riscv_putc(int c)
{

        sbi_console_putchar(c);
}

#if CHECK_EARLY_PRINTF(sbi)
early_putc_t *early_putc = riscv_putc;
#endif

static void
cn_drvinit(void *unused)
{

        if (riscv_consdev.cn_pri != CN_DEAD &&
            riscv_consdev.cn_name[0] != '\0') {
                tp = tty_alloc(&riscv_ttydevsw, NULL);
                tty_init_console(tp, 0);
                tty_makedev(tp, NULL, "%s", "rcons");

                polltime = 1;

                callout_init(&riscv_callout, 1);
                callout_reset(&riscv_callout, polltime, riscv_timeout, NULL);
        }
}

SYSINIT(cndev, SI_SUB_CONFIGURE, SI_ORDER_MIDDLE, cn_drvinit, NULL);

static void
riscvtty_outwakeup(struct tty *tp)
{
        u_char buf[MAX_BURST_LEN];
        int len;
        int i;

        for (;;) {
                len = ttydisc_getc(tp, buf, sizeof(buf));
                if (len == 0)
                        break;

                KASSERT(len == 1, ("tty error"));

                for (i = 0; i < len; i++)
                        riscv_putc(buf[i]);
        }
}

static void
riscv_timeout(void *v)
{
        int c;

        tty_lock(tp);
        while ((c = riscv_cngetc(NULL)) != -1)
                ttydisc_rint(tp, c, 0);
        ttydisc_rint_done(tp);
        tty_unlock(tp);

        callout_reset(&riscv_callout, polltime, riscv_timeout, NULL);
}

static void
riscv_cnprobe(struct consdev *cp)
{

        cp->cn_pri = CN_NORMAL;
}

static void
riscv_cninit(struct consdev *cp)
{

        strcpy(cp->cn_name, "rcons");
}

static void
riscv_cnterm(struct consdev *cp)
{

}

static void
riscv_cngrab(struct consdev *cp)
{

}

static void
riscv_cnungrab(struct consdev *cp)
{

}

static int
riscv_cngetc(struct consdev *cp)
{
        int ch;

        ch = sbi_console_getchar();
        if (ch > 0 && ch < 0xff) {
#if defined(KDB)
                kdb_alt_break(ch, &alt_break_state);
#endif
                return (ch);
        }

        return (-1);
}

static void
riscv_cnputc(struct consdev *cp, int c)
{

        riscv_putc(c);
}

/* Bus interface */

static int
rcons_probe(device_t dev)
{

        device_set_desc(dev, "RISC-V console");

        return (BUS_PROBE_DEFAULT);
}

static int
rcons_attach(device_t dev)
{
        struct rcons_softc *sc;

        if (device_get_unit(dev) != 0)
                return (ENXIO);

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

        bus_attach_children(sc->dev);

        return (0);
}

static device_method_t rcons_methods[] = {
        DEVMETHOD(device_probe,         rcons_probe),
        DEVMETHOD(device_attach,        rcons_attach),

        DEVMETHOD_END
};

static driver_t rcons_driver = {
        "rcons",
        rcons_methods,
        sizeof(struct rcons_softc)
};

DRIVER_MODULE(rcons, nexus, rcons_driver, 0, 0);