/*      $OpenBSD: qcsmptp.c,v 1.3 2026/02/06 21:32:42 kettenis Exp $    */
/*
 * Copyright (c) 2023 Patrick Wildt <patrick@blueri.se>
 *
 * 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 <sys/malloc.h>
#include <sys/atomic.h>

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

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

#define SMP2P_MAX_ENTRY         16
#define SMP2P_MAX_ENTRY_NAME    16

struct qcsmptp_smem_item {
        uint32_t magic;
#define SMP2P_MAGIC                     0x504d5324
        uint8_t version;
#define SMP2P_VERSION                   1
        unsigned features:24;
#define SMP2P_FEATURE_SSR_ACK           (1 << 0)
        uint16_t local_pid;
        uint16_t remote_pid;
        uint16_t total_entries;
        uint16_t valid_entries;
        uint32_t flags;
#define SMP2P_FLAGS_RESTART_DONE        (1 << 0)
#define SMP2P_FLAGS_RESTART_ACK         (1 << 1)

        struct {
                uint8_t name[SMP2P_MAX_ENTRY_NAME];
                uint32_t value;
        } entries[SMP2P_MAX_ENTRY];
} __packed;

struct qcsmptp_intrhand {
        TAILQ_ENTRY(qcsmptp_intrhand) ih_q;
        int (*ih_func)(void *);
        void *ih_arg;
        void *ih_ic;
        int ih_pin;
        int ih_enabled;
};

struct qcsmptp_interrupt_controller {
        TAILQ_HEAD(,qcsmptp_intrhand) ic_intrq;
        struct qcsmptp_softc *ic_sc;
        struct interrupt_controller ic_ic;
};

struct qcsmptp_entry {
        TAILQ_ENTRY(qcsmptp_entry) e_q;
        char *e_name;
        int e_namelen;
        uint32_t *e_value;
        uint32_t e_last_value;
        struct qcsmptp_interrupt_controller *e_ic;
};

struct qcsmptp_softc {
        struct device           sc_dev;
        int                     sc_node;
        void                    *sc_ih;

        uint16_t                sc_local_pid;
        uint16_t                sc_remote_pid;
        uint32_t                sc_smem_id[2];

        struct qcsmptp_smem_item *sc_in;
        struct qcsmptp_smem_item *sc_out;

        TAILQ_HEAD(,qcsmptp_entry) sc_inboundq;
        TAILQ_HEAD(,qcsmptp_entry) sc_outboundq;

        int                     sc_negotiated;
        int                     sc_ssr_ack_enabled;
        int                     sc_ssr_ack;

        uint16_t                sc_valid_entries;

        struct mbox_channel     *sc_mc;
};

int     qcsmptp_match(struct device *, void *, void *);
void    qcsmptp_attach(struct device *, struct device *, void *);
void    qcsmptp_deferred(struct device *);

const struct cfattach qcsmptp_ca = {
        sizeof (struct qcsmptp_softc), qcsmptp_match, qcsmptp_attach
};

struct cfdriver qcsmptp_cd = {
        NULL, "qcsmptp", DV_DULL
};

int     qcsmptp_intr(void *);
void    *qcsmptp_intr_establish(void *, int *, int, struct cpu_info *,
            int (*)(void *), void *, char *);
void    qcsmptp_intr_disestablish(void *);
void    qcsmptp_intr_enable(void *);
void    qcsmptp_intr_disable(void *);
void    qcsmptp_intr_barrier(void *);

extern int qcsmem_alloc(int, int, int);
extern void *qcsmem_get(int, int, int *);

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

        return OF_is_compatible(faa->fa_node, "qcom,smp2p");
}

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

        sc->sc_node = faa->fa_node;

        TAILQ_INIT(&sc->sc_inboundq);
        TAILQ_INIT(&sc->sc_outboundq);

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

        sc->sc_local_pid = OF_getpropint(faa->fa_node,
            "qcom,local-pid", 0xffff);
        sc->sc_remote_pid = OF_getpropint(faa->fa_node,
            "qcom,remote-pid", 0xffff);
        if (sc->sc_local_pid == 0xffff || sc->sc_remote_pid == 0xffff) {
                printf(": can't get pids\n");
                return;
        }

        if (OF_getpropintarray(faa->fa_node, "qcom,smem", sc->sc_smem_id,
            sizeof(sc->sc_smem_id)) != sizeof(sc->sc_smem_id)) {
                printf(": can't get smem property \n");
                return;
        }

        printf("\n");

        config_defer(self, qcsmptp_deferred);
}

void
qcsmptp_deferred(struct device *self)
{
        struct qcsmptp_softc *sc = (struct qcsmptp_softc *)self;
        struct qcsmptp_entry *e;
        int node, size;

        sc->sc_mc = mbox_channel_idx(sc->sc_node, 0, NULL);
        if (sc->sc_mc == NULL) {
                printf("%s: can't get mailbox\n", sc->sc_dev.dv_xname);
                return;
        }

        if (qcsmem_alloc(sc->sc_remote_pid, sc->sc_smem_id[0],
            sizeof(*sc->sc_in)) != 0) {
                printf("%s: can't alloc smp2p item\n", sc->sc_dev.dv_xname);
                return;
        }

        sc->sc_in = qcsmem_get(sc->sc_remote_pid, sc->sc_smem_id[0], NULL);
        if (sc->sc_in == NULL) {
                printf("%s: can't get smp2p item\n", sc->sc_dev.dv_xname);
                return;
        }

        if (qcsmem_alloc(sc->sc_remote_pid, sc->sc_smem_id[1],
            sizeof(*sc->sc_out)) != 0) {
                printf("%s: can't alloc smp2p item\n", sc->sc_dev.dv_xname);
                return;
        }

        sc->sc_out = qcsmem_get(sc->sc_remote_pid, sc->sc_smem_id[1], NULL);
        if (sc->sc_out == NULL) {
                printf("%s: can't get smp2p item\n", sc->sc_dev.dv_xname);
                return;
        }

        memset(sc->sc_out, 0, sizeof(*sc->sc_out));
        sc->sc_out->magic = SMP2P_MAGIC;
        sc->sc_out->local_pid = sc->sc_local_pid;
        sc->sc_out->remote_pid = sc->sc_remote_pid;
        sc->sc_out->total_entries = SMP2P_MAX_ENTRY;
        sc->sc_out->features = SMP2P_FEATURE_SSR_ACK;
        membar_sync();
        sc->sc_out->version = SMP2P_VERSION;
        mbox_send(sc->sc_mc, NULL, 0);

        for (node = OF_child(sc->sc_node); node; node = OF_peer(node)) {
                size = OF_getproplen(node, "qcom,entry-name");
                if (size <= 0)
                        continue;
                e = malloc(sizeof(*e), M_DEVBUF, M_WAITOK | M_ZERO);
                e->e_namelen = size;
                e->e_name = malloc(e->e_namelen, M_DEVBUF, M_WAITOK);
                OF_getprop(node, "qcom,entry-name", e->e_name,
                    e->e_namelen);
                e->e_name[e->e_namelen - 1] = '\0';

                if (OF_getproplen(node, "interrupt-controller") == 0) {
                        struct qcsmptp_interrupt_controller *ic;
                        ic = malloc(sizeof(*ic), M_DEVBUF, M_WAITOK | M_ZERO);
                        TAILQ_INIT(&ic->ic_intrq);
                        ic->ic_sc = sc;
                        ic->ic_ic.ic_node = node;
                        ic->ic_ic.ic_cookie = ic;
                        ic->ic_ic.ic_establish = qcsmptp_intr_establish;
                        ic->ic_ic.ic_disestablish = qcsmptp_intr_disestablish;
                        ic->ic_ic.ic_enable = qcsmptp_intr_enable;
                        ic->ic_ic.ic_disable = qcsmptp_intr_disable;
                        ic->ic_ic.ic_barrier = qcsmptp_intr_barrier;
                        fdt_intr_register(&ic->ic_ic);
                        e->e_ic = ic;
                        TAILQ_INSERT_TAIL(&sc->sc_inboundq, e, e_q);
                } else {
                        if (sc->sc_out->valid_entries >= SMP2P_MAX_ENTRY)
                                continue;

                        strlcpy(sc->sc_out->entries[sc->sc_out->valid_entries].name,
                            e->e_name, SMP2P_MAX_ENTRY_NAME);
                        e->e_value = &sc->sc_out->entries[sc->sc_out->valid_entries].value;
                        sc->sc_out->valid_entries++;
                        TAILQ_INSERT_TAIL(&sc->sc_outboundq, e, e_q);

                        /* TODO: provide as smem state */
                }
        }
}

int
qcsmptp_intr(void *arg)
{
        struct qcsmptp_softc *sc = arg;
        struct qcsmptp_entry *e;
        struct qcsmptp_intrhand *ih;
        uint32_t changed, val;
        int do_ack = 0, i;

        /* Do initial feature negotiation if inbound is new. */
        if (!sc->sc_negotiated) {
                if (sc->sc_in->version != sc->sc_out->version)
                        return 1;
                sc->sc_out->features &= sc->sc_in->features;
                if (sc->sc_out->features & SMP2P_FEATURE_SSR_ACK)
                        sc->sc_ssr_ack_enabled = 1;
                sc->sc_negotiated = 1;
        }
        if (!sc->sc_negotiated)
                return 1;

        /* Use ACK mechanism if negotiated. */
        if (sc->sc_ssr_ack_enabled &&
            !!(sc->sc_in->flags & SMP2P_FLAGS_RESTART_DONE) != sc->sc_ssr_ack)
                do_ack = 1;

        /* Catch up on new inbound entries that got added in the meantime. */
        for (i = sc->sc_valid_entries; i < sc->sc_in->valid_entries; i++) {
                TAILQ_FOREACH(e, &sc->sc_inboundq, e_q) {
                        if (strncmp(sc->sc_in->entries[i].name, e->e_name,
                            SMP2P_MAX_ENTRY_NAME) != 0)
                                continue;
                        e->e_value = &sc->sc_in->entries[i].value;
                }
        }
        sc->sc_valid_entries = i;

        /* For each inbound "interrupt controller". */
        TAILQ_FOREACH(e, &sc->sc_inboundq, e_q) {
                if (e->e_value == NULL)
                        continue;
                val = *e->e_value;
                if (val == e->e_last_value)
                        continue;
                changed = val ^ e->e_last_value;
                e->e_last_value = val;
                TAILQ_FOREACH(ih, &e->e_ic->ic_intrq, ih_q) {
                        if (!ih->ih_enabled)
                                continue;
                        if ((changed & (1 << ih->ih_pin)) == 0)
                                continue;
                        ih->ih_func(ih->ih_arg);
                }
        }

        if (do_ack) {
                sc->sc_ssr_ack = !sc->sc_ssr_ack;
                if (sc->sc_ssr_ack)
                        sc->sc_out->flags |= SMP2P_FLAGS_RESTART_ACK;
                else
                        sc->sc_out->flags &= ~SMP2P_FLAGS_RESTART_ACK;
                membar_sync();
                mbox_send(sc->sc_mc, NULL, 0);
        }

        return 1;
}

void *
qcsmptp_intr_establish(void *cookie, int *cells, int ipl,
    struct cpu_info *ci, int (*func)(void *), void *arg, char *name)
{
        struct qcsmptp_interrupt_controller *ic = cookie;
        struct qcsmptp_softc *sc = ic->ic_sc;
        struct qcsmptp_intrhand *ih;

        ih = malloc(sizeof(*ih), M_DEVBUF, M_WAITOK | M_ZERO);
        ih->ih_func = func;
        ih->ih_arg = arg;
        ih->ih_ic = ic;
        ih->ih_pin = cells[0];
        TAILQ_INSERT_TAIL(&ic->ic_intrq, ih, ih_q);

        qcsmptp_intr_enable(ih);

        if (ipl & IPL_WAKEUP)
                intr_set_wakeup(sc->sc_ih);

        return ih;
}

void
qcsmptp_intr_disestablish(void *cookie)
{
        struct qcsmptp_intrhand *ih = cookie;
        struct qcsmptp_interrupt_controller *ic = ih->ih_ic;

        qcsmptp_intr_disable(ih);

        TAILQ_REMOVE(&ic->ic_intrq, ih, ih_q);
        free(ih, M_DEVBUF, sizeof(*ih));
}

void
qcsmptp_intr_enable(void *cookie)
{
        struct qcsmptp_intrhand *ih = cookie;

        ih->ih_enabled = 1;
}

void
qcsmptp_intr_disable(void *cookie)
{
        struct qcsmptp_intrhand *ih = cookie;

        ih->ih_enabled = 0;
}

void
qcsmptp_intr_barrier(void *cookie)
{
        struct qcsmptp_intrhand *ih = cookie;
        struct qcsmptp_interrupt_controller *ic = ih->ih_ic;
        struct qcsmptp_softc *sc = ic->ic_sc;

        intr_barrier(sc->sc_ih);
}