/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2004-2006 Marcel Moolenaar
 * 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 THE AUTHOR 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/conf.h>
#include <sys/lock.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mutex.h>
#include <sys/queue.h>
#include <sys/serial.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <sys/rman.h>

#include <dev/scc/scc_bfe.h>
#include <dev/scc/scc_bus.h>

#include "scc_if.h"

const char scc_driver_name[] = "scc";

static MALLOC_DEFINE(M_SCC, "SCC", "SCC driver");

static int
scc_bfe_intr(void *arg)
{
        struct scc_softc *sc = arg;
        struct scc_chan *ch;
        struct scc_class *cl;
        struct scc_mode *m;
        int c, i, ipend, isrc;

        cl = sc->sc_class;
        while (!sc->sc_leaving && (ipend = SCC_IPEND(sc)) != 0) {
                i = 0, isrc = SER_INT_OVERRUN;
                while (ipend) {
                        while (i < SCC_ISRCCNT && !(ipend & isrc))
                                i++, isrc <<= 1;
                        KASSERT(i < SCC_ISRCCNT, ("%s", __func__));
                        ipend &= ~isrc;
                        for (c = 0; c < cl->cl_channels; c++) {
                                ch = &sc->sc_chan[c];
                                if (!(ch->ch_ipend & isrc))
                                        continue;
                                m = &ch->ch_mode[0];
                                if (m->ih_src[i] == NULL)
                                        continue;
                                if ((*m->ih_src[i])(m->ih_arg))
                                        ch->ch_ipend &= ~isrc;
                        }
                }
                for (c = 0; c < cl->cl_channels; c++) {
                        ch = &sc->sc_chan[c];
                        if (!ch->ch_ipend)
                                continue;
                        m = &ch->ch_mode[0];
                        if (m->ih != NULL)
                                (*m->ih)(m->ih_arg);
                        else
                                SCC_ICLEAR(sc, ch);
                }
                return (FILTER_HANDLED);
        }
        return (FILTER_STRAY);
}

int
scc_bfe_attach(device_t dev, u_int ipc)
{
        struct resource_list_entry *rle;
        struct scc_chan *ch;
        struct scc_class *cl;
        struct scc_mode *m;
        struct scc_softc *sc, *sc0;
        const char *sep;
        bus_space_handle_t bh;
        rman_res_t base, size, start, sz;
        int c, error, mode, sysdev;

        /*
         * The sc_class field defines the type of SCC we're going to work
         * with and thus the size of the softc. Replace the generic softc
         * with one that matches the SCC now that we're certain we handle
         * the device.
         */
        sc0 = device_get_softc(dev);
        cl = sc0->sc_class;
        if (cl->size > sizeof(*sc)) {
                sc = malloc(cl->size, M_SCC, M_WAITOK|M_ZERO);
                bcopy(sc0, sc, sizeof(*sc));
                device_set_softc(dev, sc);
        } else
                sc = sc0;

        size = abs(cl->cl_range) << sc->sc_bas.regshft;

        mtx_init(&sc->sc_hwmtx, "scc_hwmtx", NULL, MTX_SPIN);

        /*
         * Re-allocate. We expect that the softc contains the information
         * collected by scc_bfe_probe() intact.
         */
        sc->sc_rres = bus_alloc_resource_anywhere(dev, sc->sc_rtype,
            &sc->sc_rrid, cl->cl_channels * size, RF_ACTIVE);
        if (sc->sc_rres == NULL)
                return (ENXIO);
        sc->sc_bas.bsh = rman_get_bushandle(sc->sc_rres);
        sc->sc_bas.bst = rman_get_bustag(sc->sc_rres);

        /*
         * Allocate interrupt resources. There may be a different interrupt
         * per channel. We allocate them all...
         */
        sc->sc_chan = malloc(sizeof(struct scc_chan) * cl->cl_channels,
            M_SCC, M_WAITOK | M_ZERO);
        for (c = 0; c < cl->cl_channels; c++) {
                ch = &sc->sc_chan[c];
                /*
                 * XXX temporary hack. If we have more than 1 interrupt
                 * per channel, allocate the first for the channel. At
                 * this time only the macio bus front-end has more than
                 * 1 interrupt per channel and we don't use the 2nd and
                 * 3rd, because we don't support DMA yet.
                 */
                ch->ch_irid = c * ipc;
                ch->ch_ires = bus_alloc_resource_any(dev, SYS_RES_IRQ,
                    &ch->ch_irid, RF_ACTIVE | RF_SHAREABLE);
                if (ipc == 0)
                        break;
        }

        /*
         * Create the control structures for our children. Probe devices
         * and query them to see if we can reset the hardware.
         */
        sysdev = 0;
        base = rman_get_start(sc->sc_rres);
        sz = (size != 0) ? size : rman_get_size(sc->sc_rres);
        start = base + ((cl->cl_range < 0) ? size * (cl->cl_channels - 1) : 0);
        for (c = 0; c < cl->cl_channels; c++) {
                ch = &sc->sc_chan[c];
                resource_list_init(&ch->ch_rlist);
                ch->ch_nr = c + 1;

                if (!SCC_ENABLED(sc, ch))
                        goto next;

                ch->ch_enabled = 1;
                resource_list_add(&ch->ch_rlist, sc->sc_rtype, 0, start,
                    start + sz - 1, sz);
                rle = resource_list_find(&ch->ch_rlist, sc->sc_rtype, 0);
                rle->res = &ch->ch_rres;
                bus_space_subregion(rman_get_bustag(sc->sc_rres),
                    rman_get_bushandle(sc->sc_rres), start - base, sz, &bh);
                rman_set_bushandle(rle->res, bh);
                rman_set_bustag(rle->res, rman_get_bustag(sc->sc_rres));

                resource_list_add(&ch->ch_rlist, SYS_RES_IRQ, 0, c, c, 1);
                rle = resource_list_find(&ch->ch_rlist, SYS_RES_IRQ, 0);
                rle->res = (ch->ch_ires != NULL) ? ch->ch_ires :
                            sc->sc_chan[0].ch_ires;

                for (mode = 0; mode < SCC_NMODES; mode++) {
                        m = &ch->ch_mode[mode];
                        m->m_chan = ch;
                        m->m_mode = 1U << mode;
                        if ((cl->cl_modes & m->m_mode) == 0 || ch->ch_sysdev)
                                continue;
                        m->m_dev = device_add_child(dev, NULL, DEVICE_UNIT_ANY);
                        device_set_ivars(m->m_dev, (void *)m);
                        error = device_probe_child(dev, m->m_dev);
                        if (!error) {
                                m->m_probed = 1;
                                m->m_sysdev = SERDEV_SYSDEV(m->m_dev) ? 1 : 0;
                                ch->ch_sysdev |= m->m_sysdev;
                        }
                }

         next:
                start += (cl->cl_range < 0) ? -size : size;
                sysdev |= ch->ch_sysdev;
        }

        /*
         * Have the hardware driver initialize the hardware. Tell it
         * whether or not a hardware reset should be performed.
         */
        if (bootverbose) {
                device_printf(dev, "%sresetting hardware\n",
                    (sysdev) ? "not " : "");
        }
        error = SCC_ATTACH(sc, !sysdev);
        if (error)
                goto fail;

        /*
         * Setup our interrupt handler. Make it FAST under the assumption
         * that our children's are fast as well. We make it MPSAFE as soon
         * as a child sets up a MPSAFE interrupt handler.
         * Of course, if we can't setup a fast handler, we make it MPSAFE
         * right away.
         */
        for (c = 0; c < cl->cl_channels; c++) {
                ch = &sc->sc_chan[c];
                if (ch->ch_ires == NULL)
                        continue;
                error = bus_setup_intr(dev, ch->ch_ires,
                    INTR_TYPE_TTY, scc_bfe_intr, NULL, sc,
                    &ch->ch_icookie);
                if (error) {
                        error = bus_setup_intr(dev, ch->ch_ires,
                            INTR_TYPE_TTY | INTR_MPSAFE, NULL,
                            (driver_intr_t *)scc_bfe_intr, sc, &ch->ch_icookie);
                } else
                        sc->sc_fastintr = 1;

                if (error) {
                        device_printf(dev, "could not activate interrupt\n");
                        bus_release_resource(dev, SYS_RES_IRQ, ch->ch_irid,
                            ch->ch_ires);
                        ch->ch_ires = NULL;
                }
        }
        sc->sc_polled = 1;
        for (c = 0; c < cl->cl_channels; c++) {
                if (sc->sc_chan[0].ch_ires != NULL)
                        sc->sc_polled = 0;
        }

        /*
         * Attach all child devices that were probed successfully.
         */
        for (c = 0; c < cl->cl_channels; c++) {
                ch = &sc->sc_chan[c];
                for (mode = 0; mode < SCC_NMODES; mode++) {
                        m = &ch->ch_mode[mode];
                        if (!m->m_probed)
                                continue;
                        error = device_attach(m->m_dev);
                        if (error)
                                continue;
                        m->m_attached = 1;
                }
        }

        if (bootverbose && (sc->sc_fastintr || sc->sc_polled)) {
                sep = "";
                device_print_prettyname(dev);
                if (sc->sc_fastintr) {
                        printf("%sfast interrupt", sep);
                        sep = ", ";
                }
                if (sc->sc_polled) {
                        printf("%spolled mode", sep);
                        sep = ", ";
                }
                printf("\n");
        }

        return (0);

 fail:
        for (c = 0; c < cl->cl_channels; c++) {
                ch = &sc->sc_chan[c];
                if (ch->ch_ires == NULL)
                        continue;
                bus_release_resource(dev, SYS_RES_IRQ, ch->ch_irid,
                    ch->ch_ires);
        }
        bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);
        return (error);
}

int
scc_bfe_detach(device_t dev)
{
        struct scc_chan *ch;
        struct scc_class *cl;
        struct scc_mode *m;
        struct scc_softc *sc;
        int chan, error, mode;

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

        /* Detach our children. */
        error = 0;
        for (chan = 0; chan < cl->cl_channels; chan++) {
                ch = &sc->sc_chan[chan];
                for (mode = 0; mode < SCC_NMODES; mode++) {
                        m = &ch->ch_mode[mode];
                        if (!m->m_attached)
                                continue;
                        if (device_detach(m->m_dev) != 0)
                                error = ENXIO;
                        else
                                m->m_attached = 0;
                }
        }

        if (error)
                return (error);

        for (chan = 0; chan < cl->cl_channels; chan++) {
                ch = &sc->sc_chan[chan];
                if (ch->ch_ires == NULL)
                        continue;
                bus_teardown_intr(dev, ch->ch_ires, ch->ch_icookie);
                bus_release_resource(dev, SYS_RES_IRQ, ch->ch_irid,
                    ch->ch_ires);
        }
        bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);

        free(sc->sc_chan, M_SCC);

        mtx_destroy(&sc->sc_hwmtx);
        return (0);
}

int
scc_bfe_probe(device_t dev, u_int regshft, u_int rclk, u_int rid)
{
        struct scc_softc *sc;
        struct scc_class *cl;
        u_long size, sz;
        int error;

        /*
         * Initialize the instance. Note that the instance (=softc) does
         * not necessarily match the hardware specific softc. We can't do
         * anything about it now, because we may not attach to the device.
         * Hardware drivers cannot use any of the class specific fields
         * while probing.
         */
        sc = device_get_softc(dev);
        cl = sc->sc_class;
        kobj_init((kobj_t)sc, (kobj_class_t)cl);
        sc->sc_dev = dev;
        if (device_get_desc(dev) == NULL)
                device_set_desc(dev, cl->name);

        size = abs(cl->cl_range) << regshft;

        /*
         * Allocate the register resource. We assume that all SCCs have a
         * single register window in either I/O port space or memory mapped
         * I/O space. Any SCC that needs multiple windows will consequently
         * not be supported by this driver as-is.
         */
        sc->sc_rrid = rid;
        sc->sc_rtype = SYS_RES_MEMORY;
        sc->sc_rres = bus_alloc_resource_anywhere(dev, sc->sc_rtype,
            &sc->sc_rrid, cl->cl_channels * size, RF_ACTIVE);
        if (sc->sc_rres == NULL) {
                sc->sc_rrid = rid;
                sc->sc_rtype = SYS_RES_IOPORT;
                sc->sc_rres = bus_alloc_resource_anywhere(dev, sc->sc_rtype,
                    &sc->sc_rrid, cl->cl_channels * size, RF_ACTIVE);
                if (sc->sc_rres == NULL)
                        return (ENXIO);
        }

        /*
         * Fill in the bus access structure and call the hardware specific
         * probe method.
         */
        sz = (size != 0) ? size : rman_get_size(sc->sc_rres);
        sc->sc_bas.bsh = rman_get_bushandle(sc->sc_rres);
        sc->sc_bas.bst = rman_get_bustag(sc->sc_rres);
        sc->sc_bas.range = sz;
        sc->sc_bas.rclk = rclk;
        sc->sc_bas.regshft = regshft;

        error = SCC_PROBE(sc);
        bus_release_resource(dev, sc->sc_rtype, sc->sc_rrid, sc->sc_rres);
        return ((error == 0) ? BUS_PROBE_DEFAULT : error);
}

struct resource *
scc_bus_alloc_resource(device_t dev, device_t child, int type, int rid __unused,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
        struct resource_list_entry *rle;
        struct scc_chan *ch;
        struct scc_mode *m;

        if (device_get_parent(child) != dev)
                return (NULL);

        /* We only support default allocations. */
        if (!RMAN_IS_DEFAULT_RANGE(start, end))
                return (NULL);

        m = device_get_ivars(child);
        ch = m->m_chan;
        rle = resource_list_find(&ch->ch_rlist, type, 0);
        if (rle == NULL)
                return (NULL);
        return (rle->res);
}

int
scc_bus_get_resource(device_t dev, device_t child, int type, int rid,
    rman_res_t *startp, rman_res_t *countp)
{
        struct resource_list_entry *rle;
        struct scc_chan *ch;
        struct scc_mode *m;

        if (device_get_parent(child) != dev)
                return (EINVAL);

        m = device_get_ivars(child);
        ch = m->m_chan;
        rle = resource_list_find(&ch->ch_rlist, type, rid);
        if (rle == NULL)
                return (EINVAL);

        if (startp != NULL)
                *startp = rle->start;
        if (countp != NULL)
                *countp = rle->count;
        return (0);
}

int
scc_bus_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
{
        struct scc_chan *ch;
        struct scc_class *cl;
        struct scc_mode *m;
        struct scc_softc *sc;

        if (device_get_parent(child) != dev)
                return (EINVAL);

        sc = device_get_softc(dev);
        cl = sc->sc_class;
        m = device_get_ivars(child);
        ch = m->m_chan;

        switch (index) {
        case SCC_IVAR_CHANNEL:
                *result = ch->ch_nr;
                break;
        case SCC_IVAR_CLASS:
                *result = cl->cl_class;
                break;
        case SCC_IVAR_CLOCK:
                *result = sc->sc_bas.rclk;
                break;
        case SCC_IVAR_MODE:
                *result = m->m_mode;
                break;
        case SCC_IVAR_REGSHFT:
                *result = sc->sc_bas.regshft;
                break;
        case SCC_IVAR_HWMTX:
                *result = (uintptr_t)&sc->sc_hwmtx;
                break;
        default:
                return (EINVAL);
        }
        return (0);
}

int
scc_bus_release_resource(device_t dev, device_t child, struct resource *res)
{
        struct resource_list_entry *rle;
        struct scc_chan *ch;
        struct scc_mode *m;

        if (device_get_parent(child) != dev)
                return (EINVAL);

        m = device_get_ivars(child);
        ch = m->m_chan;
        rle = resource_list_find(&ch->ch_rlist, rman_get_type(res),
            rman_get_rid(res));
        return ((rle == NULL) ? EINVAL : 0);
}

int
scc_bus_setup_intr(device_t dev, device_t child, struct resource *r, int flags,
    driver_filter_t *filt, void (*ihand)(void *), void *arg, void **cookiep)
{
        struct scc_chan *ch;
        struct scc_mode *m;
        struct scc_softc *sc;
        int c, i, isrc;

        if (device_get_parent(child) != dev)
                return (EINVAL);

        /* Interrupt handlers must be FAST or MPSAFE. */
        if (filt == NULL && !(flags & INTR_MPSAFE))
                return (EINVAL);

        sc = device_get_softc(dev);
        if (sc->sc_polled)
                return (ENXIO);

        if (sc->sc_fastintr && filt == NULL) {
                sc->sc_fastintr = 0;
                for (c = 0; c < sc->sc_class->cl_channels; c++) {
                        ch = &sc->sc_chan[c];
                        if (ch->ch_ires == NULL)
                                continue;
                        bus_teardown_intr(dev, ch->ch_ires, ch->ch_icookie);
                        bus_setup_intr(dev, ch->ch_ires,
                            INTR_TYPE_TTY | INTR_MPSAFE, NULL,
                            (driver_intr_t *)scc_bfe_intr, sc, &ch->ch_icookie);
                }
        }

        m = device_get_ivars(child);
        m->m_hasintr = 1;
        m->m_fastintr = (filt != NULL) ? 1 : 0;
        m->ih = (filt != NULL) ? filt : (driver_filter_t *)ihand;
        m->ih_arg = arg;

        i = 0, isrc = SER_INT_OVERRUN;
        while (i < SCC_ISRCCNT) {
                m->ih_src[i] = SERDEV_IHAND(child, isrc);
                if (m->ih_src[i] != NULL)
                        m->ih = NULL;
                i++, isrc <<= 1;
        }
        return (0);
}

int
scc_bus_teardown_intr(device_t dev, device_t child, struct resource *r,
    void *cookie)
{
        struct scc_mode *m;
        int i;

        if (device_get_parent(child) != dev)
                return (EINVAL);

        m = device_get_ivars(child);
        if (!m->m_hasintr)
                return (EINVAL);

        m->m_hasintr = 0;
        m->m_fastintr = 0;
        m->ih = NULL;
        m->ih_arg = NULL;
        for (i = 0; i < SCC_ISRCCNT; i++)
                m->ih_src[i] = NULL;
        return (0);
}