/*-
 * Copyright (C) 2011,2015 by Nathan Whitehorn. 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 ``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 TOOLS GMBH 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/cdefs.h>
#include <sys/endian.h>
#include <sys/param.h>
#include <sys/conf.h>
#include <sys/cons.h>
#include <sys/kdb.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <sys/tty.h>

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

#include <machine/bus.h>

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

#include "opal.h"
#include "uart_if.h"

struct uart_opal_softc {
        device_t dev;
        phandle_t node;
        int vtermid;

        struct tty *tp;
        struct resource *irqres;
        int irqrid;
        struct callout callout;
        void *sc_icookie;
        int polltime;

        struct mtx sc_mtx;
        int protocol;

        char opal_inbuf[16];
        uint64_t inbuflen;
        uint8_t outseqno;
#if defined(KDB)
        int alt_break_state;
#endif
};

static struct uart_opal_softc   *console_sc = NULL;
static struct consdev *stdout_cp;

enum {
        OPAL_RAW, OPAL_HVSI
};

#define VS_DATA_PACKET_HEADER           0xff
#define VS_CONTROL_PACKET_HEADER        0xfe
#define  VSV_SET_MODEM_CTL              0x01
#define  VSV_MODEM_CTL_UPDATE           0x02
#define  VSV_RENEGOTIATE_CONNECTION     0x03
#define VS_QUERY_PACKET_HEADER          0xfd
#define  VSV_SEND_VERSION_NUMBER        0x01
#define  VSV_SEND_MODEM_CTL_STATUS      0x02
#define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc

static int uart_opal_probe(device_t dev);
static int uart_opal_attach(device_t dev);
static void uart_opal_intr(void *v);

static device_method_t uart_opal_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         uart_opal_probe),
        DEVMETHOD(device_attach,        uart_opal_attach),

        DEVMETHOD_END
};

static driver_t uart_opal_driver = {
        "uart",
        uart_opal_methods,
        sizeof(struct uart_opal_softc),
};

DRIVER_MODULE(uart_opal, opalcons, uart_opal_driver, 0, 0);

static int uart_opal_getc(struct uart_opal_softc *sc);
static cn_probe_t uart_opal_cnprobe;
static cn_init_t uart_opal_cninit;
static cn_term_t uart_opal_cnterm;
static cn_getc_t uart_opal_cngetc;
static cn_putc_t uart_opal_cnputc;
static cn_grab_t uart_opal_cngrab;
static cn_ungrab_t uart_opal_cnungrab;

CONSOLE_DRIVER(uart_opal);

static void uart_opal_ttyoutwakeup(struct tty *tp);

static struct ttydevsw uart_opal_tty_class = {
        .tsw_flags      = TF_INITLOCK|TF_CALLOUT,
        .tsw_outwakeup  = uart_opal_ttyoutwakeup,
};

static struct {
        char tmpbuf[16];
        uint64_t size;
        struct mtx mtx;
} opalcons_buffer;

static void
uart_opal_real_map_outbuffer(uint64_t *bufferp, uint64_t *lenp)
{

        if (!mtx_initialized(&opalcons_buffer.mtx))
                mtx_init(&opalcons_buffer.mtx, "uart_opal", NULL,
                    MTX_SPIN | MTX_QUIET | MTX_NOWITNESS);

        if (!pmap_bootstrapped)
                return;

        mtx_lock_spin(&opalcons_buffer.mtx);

        opalcons_buffer.size = *(uint64_t *)(*lenp) =
            min(sizeof(opalcons_buffer.tmpbuf), *(uint64_t *)(*lenp));
        memcpy(opalcons_buffer.tmpbuf, (void *)(*bufferp),
            *(uint64_t *)(*lenp));
        *bufferp = (uint64_t)opalcons_buffer.tmpbuf;
        *lenp = (uint64_t)&opalcons_buffer.size;
}

static void
uart_opal_real_unmap_outbuffer(uint64_t *len)
{

        if (!pmap_bootstrapped)
                return;

        mtx_assert(&opalcons_buffer.mtx, MA_OWNED);
        *len = opalcons_buffer.size;
        mtx_unlock_spin(&opalcons_buffer.mtx);
}

static int64_t
uart_opal_console_write_buffer_space(int vtermid)
{
        int64_t buffer_space_val = 0;
        vm_paddr_t buffer_space_ptr;

        if (pmap_bootstrapped)
                buffer_space_ptr = vtophys(&buffer_space_val);
        else
                buffer_space_ptr = (vm_paddr_t)&buffer_space_val;

        if (opal_call(OPAL_CONSOLE_WRITE_BUFFER_SPACE, vtermid,
            buffer_space_ptr) != OPAL_SUCCESS)
                return (-1);

        return (be64toh(buffer_space_val));
}

static int
uart_opal_probe_node(struct uart_opal_softc *sc)
{
        phandle_t node = sc->node;
        uint32_t reg;
        char buf[64];

        sc->inbuflen = 0;
        sc->outseqno = 0;

        if (OF_getprop(node, "device_type", buf, sizeof(buf)) <= 0)
                return (ENXIO);
        if (strcmp(buf, "serial") != 0)
                return (ENXIO);

        reg = -1;
        OF_getencprop(node, "reg", &reg, sizeof(reg));
        if (reg == -1)
                return (ENXIO);
        sc->vtermid = reg;
        sc->node = node;

        if (OF_getprop(node, "compatible", buf, sizeof(buf)) <= 0)
                return (ENXIO);
        if (strcmp(buf, "ibm,opal-console-raw") == 0) {
                sc->protocol = OPAL_RAW;
                return (0);
        } else if (strcmp(buf, "ibm,opal-console-hvsi") == 0) {
                sc->protocol = OPAL_HVSI;
                return (0);
        }

        return (ENXIO);
}

static int
uart_opal_probe(device_t dev)
{
        struct uart_opal_softc sc;
        int err;

        sc.node = ofw_bus_get_node(dev);
        err = uart_opal_probe_node(&sc);
        if (err != 0)
                return (err);

        device_set_desc(dev, "OPAL Serial Port");

        return (err);
}

static void
uart_opal_cnprobe(struct consdev *cp)
{
        char buf[64];
        phandle_t input, chosen;
        static struct uart_opal_softc sc;

        if (opal_check() != 0)
                goto fail;

        if ((chosen = OF_finddevice("/chosen")) == -1)
                goto fail;

        /* Check if OF has an active stdin/stdout */
        if (OF_getprop(chosen, "linux,stdout-path", buf, sizeof(buf)) <= 0)
                goto fail;

        input = OF_finddevice(buf);
        if (input == -1)
                goto fail;

        sc.node = input;
        if (uart_opal_probe_node(&sc) != 0)
                goto fail;
        mtx_init(&sc.sc_mtx, "uart_opal", NULL, MTX_SPIN | MTX_QUIET |
            MTX_NOWITNESS);

        cp->cn_pri = CN_NORMAL;
        console_sc = &sc;
        cp->cn_arg = console_sc;
        stdout_cp = cp;
        return;

fail:
        cp->cn_pri = CN_DEAD;
        return;
}

static int
uart_opal_attach(device_t dev)
{
        struct uart_opal_softc *sc;
        int unit;

        sc = device_get_softc(dev);
        sc->node = ofw_bus_get_node(dev);
        uart_opal_probe_node(sc);

        unit = device_get_unit(dev);
        mtx_init(&sc->sc_mtx, device_get_nameunit(dev), NULL,
            MTX_SPIN | MTX_QUIET | MTX_NOWITNESS);

        if (console_sc != NULL && console_sc->vtermid == sc->vtermid) {
                device_printf(dev, "console\n");
                device_set_softc(dev, console_sc);
                sc = console_sc;
                sprintf(uart_opal_consdev.cn_name, "ttyu%r", unit);
        }
        sc->tp = tty_alloc(&uart_opal_tty_class, sc);

        if (console_sc == sc)
                tty_init_console(sc->tp, 0);

        sc->dev = dev;
        sc->irqrid = 0;
        sc->irqres = bus_alloc_resource_any(dev, SYS_RES_IRQ, &sc->irqrid,
            RF_ACTIVE | RF_SHAREABLE);
        if (sc->irqres != NULL) {
                bus_setup_intr(dev, sc->irqres, INTR_TYPE_TTY | INTR_MPSAFE,
                    NULL, uart_opal_intr, sc, &sc->sc_icookie);
        } else {
                callout_init(&sc->callout, CALLOUT_MPSAFE);
                sc->polltime = hz / 20;
                if (sc->polltime < 1)
                        sc->polltime = 1;
                callout_reset(&sc->callout, sc->polltime, uart_opal_intr, sc);
        }

        tty_makedev(sc->tp, NULL, "u%r", unit);

        return (0);
}

static void
uart_opal_cninit(struct consdev *cp)
{

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

static void
uart_opal_cnterm(struct consdev *cp)
{
}

static int
uart_opal_get(struct uart_opal_softc *sc, void *buffer, size_t bufsize)
{
        int err;
        int hdr = 0;

        if (sc->protocol == OPAL_RAW) {
                uint64_t len = htobe64(bufsize);
                uint64_t olen = (uint64_t)&len;
                uint64_t obuf = (uint64_t)buffer;

                if (pmap_bootstrapped) {
                        olen = vtophys(&len);
                        obuf = vtophys(buffer);
                }

                err = opal_call(OPAL_CONSOLE_READ, sc->vtermid, olen, obuf);
                if (err != OPAL_SUCCESS)
                        return (-1);

                bufsize = be64toh(len);
        } else {
                uart_lock(&sc->sc_mtx);
                if (sc->inbuflen == 0) {
                        err = opal_call(OPAL_CONSOLE_READ, sc->vtermid,
                            &sc->inbuflen, sc->opal_inbuf);
                        if (err != OPAL_SUCCESS) {
                                uart_unlock(&sc->sc_mtx);
                                return (-1);
                        }
                        hdr = 1; 
                        sc->inbuflen = be64toh(sc->inbuflen);
                }

                if (sc->inbuflen == 0) {
                        uart_unlock(&sc->sc_mtx);
                        return (0);
                }

                if (bufsize > sc->inbuflen)
                        bufsize = sc->inbuflen;

                if (hdr == 1) {
                        sc->inbuflen = sc->inbuflen - 4;
                        /* The HVSI protocol has a 4 byte header, skip it */
                        memmove(&sc->opal_inbuf[0], &sc->opal_inbuf[4],
                            sc->inbuflen);
                }

                memcpy(buffer, sc->opal_inbuf, bufsize);
                sc->inbuflen -= bufsize;
                if (sc->inbuflen > 0)
                        memmove(&sc->opal_inbuf[0], &sc->opal_inbuf[bufsize],
                            sc->inbuflen);

                uart_unlock(&sc->sc_mtx);
        }

        return (bufsize);
}

static int
uart_opal_put(struct uart_opal_softc *sc, void *buffer, size_t bufsize)
{
        uint16_t seqno;
        uint64_t len;
        char    cbuf[16];
        int     err;
        uint64_t olen = (uint64_t)&len;
        uint64_t obuf = (uint64_t)cbuf;

        if (sc->protocol == OPAL_RAW) {
                obuf = (uint64_t)buffer;
                len = bufsize;

                uart_opal_real_map_outbuffer(&obuf, &olen);
                *(uint64_t*)olen = htobe64(*(uint64_t*)olen);
                err = opal_call(OPAL_CONSOLE_WRITE, sc->vtermid, olen, obuf);
                *(uint64_t*)olen = be64toh(*(uint64_t*)olen);
                uart_opal_real_unmap_outbuffer(&len);
        } else {
                uart_lock(&sc->sc_mtx);
                if (bufsize > 12)
                        bufsize = 12;
                seqno = sc->outseqno++;
                cbuf[0] = VS_DATA_PACKET_HEADER;
                cbuf[1] = 4 + bufsize; /* total length */
                cbuf[2] = (seqno >> 8) & 0xff;
                cbuf[3] = seqno & 0xff;
                memcpy(&cbuf[4], buffer, bufsize);
                len = 4 + bufsize;

                uart_opal_real_map_outbuffer(&obuf, &olen);
                *(uint64_t*)olen = htobe64(*(uint64_t*)olen);
                err = opal_call(OPAL_CONSOLE_WRITE, sc->vtermid, olen, obuf);
                *(uint64_t*)olen = be64toh(*(uint64_t*)olen);
                uart_opal_real_unmap_outbuffer(&len);

                uart_unlock(&sc->sc_mtx);

                len -= 4;
        }

        if (err == OPAL_SUCCESS)
                return (len);
        else if (err == OPAL_BUSY_EVENT)
                return(0);

        return (-1);
}

static int
uart_opal_cngetc(struct consdev *cp)
{
        return (uart_opal_getc(cp->cn_arg));
}

static int
uart_opal_getc(struct uart_opal_softc *sc)
{
        unsigned char c;
        int retval;

        retval = uart_opal_get(sc, &c, 1);
        if (retval != 1)
                return (-1);
#if defined(KDB)
        kdb_alt_break(c, &sc->alt_break_state);
#endif

        return (c);
}

static void
uart_opal_cnputc(struct consdev *cp, int c)
{
        unsigned char ch = c;
        int a;

        if (1) {
                /* Clear FIFO if needed. Must be repeated few times. */
                for (a = 0; a < 20; a++) {
                        opal_call(OPAL_POLL_EVENTS, NULL);
                }
        }
        uart_opal_put(cp->cn_arg, &ch, 1);
}

static void
uart_opal_cngrab(struct consdev *cp)
{
}

static void
uart_opal_cnungrab(struct consdev *cp)
{
}

static void
uart_opal_ttyoutwakeup(struct tty *tp)
{
        struct uart_opal_softc *sc;
        char buffer[8];
        int len;
        int64_t buffer_space;

        sc = tty_softc(tp);

        while ((len = ttydisc_getc(tp, buffer, sizeof(buffer))) != 0) {
                int bytes_written = 0;
                while (bytes_written == 0) {
                        buffer_space = uart_opal_console_write_buffer_space(sc->vtermid);
                        if (buffer_space == -1)
                                /* OPAL failure or invalid terminal */
                                break;
                        else if (buffer_space >= len)
                                bytes_written = uart_opal_put(sc, buffer, len);

                        if (bytes_written == 0)
                                /* OPAL must be busy, poll and retry */
                                opal_call(OPAL_POLL_EVENTS, NULL);
                        else if (bytes_written == -1)
                                /* OPAL failure or invalid terminal */
                                break;
                }
        }
}

static void
uart_opal_intr(void *v)
{
        struct uart_opal_softc *sc = v;
        struct tty *tp = sc->tp;
        int c;

        tty_lock(tp);
        while ((c = uart_opal_getc(sc)) > 0)
                ttydisc_rint(tp, c, 0);
        ttydisc_rint_done(tp);
        tty_unlock(tp);

        opal_call(OPAL_POLL_EVENTS, NULL);

        if (sc->irqres == NULL)
                callout_reset(&sc->callout, sc->polltime, uart_opal_intr, sc);
}

static int
opalcons_probe(device_t dev)
{
        const char *name;

        name = ofw_bus_get_name(dev);
        if (name == NULL || strcmp(name, "consoles") != 0)
                return (ENXIO);

        device_set_desc(dev, "OPAL Consoles");
        return (BUS_PROBE_SPECIFIC);
}

static int 
opalcons_attach(device_t dev)
{
        phandle_t child;
        device_t cdev;
        struct ofw_bus_devinfo *dinfo;

        for (child = OF_child(ofw_bus_get_node(dev)); child != 0;
            child = OF_peer(child)) {
                dinfo = malloc(sizeof(*dinfo), M_DEVBUF, M_WAITOK | M_ZERO);
                if (ofw_bus_gen_setup_devinfo(dinfo, child) != 0) {
                        free(dinfo, M_DEVBUF);
                        continue;
                }
                cdev = device_add_child(dev, NULL, DEVICE_UNIT_ANY);
                if (cdev == NULL) {
                        device_printf(dev, "<%s>: device_add_child failed\n",
                            dinfo->obd_name);
                        ofw_bus_gen_destroy_devinfo(dinfo);
                        free(dinfo, M_DEVBUF);
                        continue;
                }
                device_set_ivars(cdev, dinfo);
        }

        bus_attach_children(dev);
        return (0);
}

static const struct ofw_bus_devinfo *
opalcons_get_devinfo(device_t dev, device_t child)
{
        return (device_get_ivars(child));
}

static device_method_t opalcons_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         opalcons_probe),
        DEVMETHOD(device_attach,        opalcons_attach),

        /* ofw_bus interface */
        DEVMETHOD(ofw_bus_get_devinfo,  opalcons_get_devinfo),
        DEVMETHOD(ofw_bus_get_compat,   ofw_bus_gen_get_compat),
        DEVMETHOD(ofw_bus_get_model,    ofw_bus_gen_get_model),
        DEVMETHOD(ofw_bus_get_name,     ofw_bus_gen_get_name),
        DEVMETHOD(ofw_bus_get_node,     ofw_bus_gen_get_node),
        DEVMETHOD(ofw_bus_get_type,     ofw_bus_gen_get_type),

        DEVMETHOD_END
};

static driver_t opalcons_driver = {
        "opalcons",
        opalcons_methods,
        0
};

DRIVER_MODULE(opalcons, opal, opalcons_driver, 0, 0);