/*      $OpenBSD: qcdrm.c,v 1.1 2025/07/17 15:52:10 kettenis Exp $      */
/*
 * Copyright (c) 2025 Mark Kettenis <kettenis@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/device.h>

#include <machine/bus.h>
#include <machine/fdt.h>
#include <machine/simplebusvar.h>

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

#define MDSS_HW_INTR_STATUS     0x10

struct qcdrm_intrhand {
        int (*ih_func)(void *);
        void *ih_arg;
        int ih_ipl;
        void *ih_sc;
};

struct qcdrm_softc {
        struct simplebus_softc  sc_sbus;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;
        void                    *sc_ih;

        struct qcdrm_intrhand   sc_handlers[32];
        struct interrupt_controller sc_ic;
};

int     qcdrm_match(struct device *, void *, void *);
void    qcdrm_attach(struct device *, struct device *, void *);

const struct cfattach qcdrm_ca = {
        sizeof(struct qcdrm_softc), qcdrm_match, qcdrm_attach
};

struct cfdriver qcdrm_cd = {
        NULL, "qcdrm", DV_DULL
};

void    *qcdrm_intr_establish(void *, int *, int, struct cpu_info *,
            int (*)(void *), void *, char *);
void    qcdrm_intr_disestablish(void *);
void    qcdrm_intr_barrier(void *);
int     qcdrm_intr(void *);

int
qcdrm_match(struct device *parent, void *match, void *aux)
{
        struct fdt_attach_args *faa = aux;

        return (OF_is_compatible(faa->fa_node, "qcom,sc8280xp-mdss") ||
            OF_is_compatible(faa->fa_node, "qcom,x1e80100-mdss"));
}

void
qcdrm_attach(struct device *parent, struct device *self, void *aux)
{
        struct qcdrm_softc *sc = (struct qcdrm_softc *)self;
        struct fdt_attach_args *faa = aux;

        if (faa->fa_nreg < 1) {
                printf(": no registers\n");
                return;
        }

        sc->sc_iot = faa->fa_iot;

        if (bus_space_map(sc->sc_iot, faa->fa_reg[0].addr,
            faa->fa_reg[0].size, 0, &sc->sc_ioh)) {
                printf(": can't map registers\n");
                return;
        }

        sc->sc_ih = fdt_intr_establish(faa->fa_node, IPL_BIO, qcdrm_intr,
            sc, sc->sc_sbus.sc_dev.dv_xname);
        if (sc->sc_ih == NULL) {
                printf(": can't establish interrupt\n");
                return;
        }

        sc->sc_ic.ic_node = faa->fa_node;
        sc->sc_ic.ic_cookie = sc;
        sc->sc_ic.ic_establish = qcdrm_intr_establish;
        sc->sc_ic.ic_disestablish = qcdrm_intr_disestablish;
        sc->sc_ic.ic_barrier = qcdrm_intr_barrier;
        fdt_intr_register(&sc->sc_ic);

        simplebus_attach(parent, &sc->sc_sbus.sc_dev, faa);
}

void *
qcdrm_intr_establish(void *cookie, int *cells, int ipl,
    struct cpu_info *ci, int (*func)(void *), void *arg, char *name)
{
        struct qcdrm_softc *sc = cookie;
        int bit = cells[0];

        if (bit < 0 || bit >= 32)
                return NULL;

        sc->sc_handlers[bit].ih_func = func;
        sc->sc_handlers[bit].ih_arg = arg;
        sc->sc_handlers[bit].ih_ipl = ipl & IPL_IRQMASK;
        sc->sc_handlers[bit].ih_sc = sc;

        return &sc->sc_handlers[bit];
}

void
qcdrm_intr_disestablish(void *cookie)
{
        struct qcdrm_intrhand *ih = cookie;

        ih->ih_func = NULL;
}

void
qcdrm_intr_barrier(void *cookie)
{
        struct qcdrm_intrhand *ih = cookie;
        struct qcdrm_softc *sc = ih->ih_sc;

        intr_barrier(sc->sc_ih);
}

int
qcdrm_intr(void *arg)
{
        struct qcdrm_softc *sc = arg;
        int bit, handled = 0;
        uint32_t stat;
        int s;

        stat = bus_space_read_4(sc->sc_iot, sc->sc_ioh, MDSS_HW_INTR_STATUS);

        for (bit = 0; bit < 32; bit++) {
                if ((stat & (1U << bit)) == 0)
                        continue;

                if (sc->sc_handlers[bit].ih_func == NULL)
                        continue;

                s = splraise(sc->sc_handlers[bit].ih_ipl);
                sc->sc_handlers[bit].ih_func(sc->sc_handlers[bit].ih_arg);
                splx(s);

                handled = 1;
        }

        return handled;
}