/* $NetBSD: qcomsmptp.c,v 1.1 2024/12/30 12:31:10 jmcneill Exp $ */
/*      $OpenBSD: qcsmptp.c,v 1.2 2023/07/04 14:32:21 patrick 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/kmem.h>

#include <dev/acpi/acpivar.h>
#include <dev/acpi/qcomipcc.h>
#include <dev/acpi/qcomsmem.h>
#include <dev/acpi/qcomsmptp.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 qcsmptp_entry {
        TAILQ_ENTRY(qcsmptp_entry) e_q;
        const char *e_name;
        uint32_t *e_value;
        uint32_t e_last_value;
        struct qcsmptp_interrupt_controller *e_ic;
};

struct qcsmptp_softc {
        device_t                sc_dev;
        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;

        void                    *sc_ipcc;
};

static struct qcsmptp_interrupt_controller *qcsmptp_ic = NULL;

static int      qcsmptp_match(device_t, cfdata_t, void *);
static void     qcsmptp_attach(device_t, device_t, void *);

static int      qcsmptp_intr(void *);

CFATTACH_DECL_NEW(qcomsmptp, sizeof(struct qcsmptp_softc),
    qcsmptp_match, qcsmptp_attach, NULL, NULL);

#define IPCC_CLIENT_LPASS       3
#define IPCC_MPROC_SIGNAL_SMP2P 2

#define QCSMPTP_X1E_LOCAL_PID   0
#define QCSMPTP_X1E_REMOTE_PID  2
#define QCSMPTP_X1E_SMEM_ID0    443
#define QCSMPTP_X1E_SMEM_ID1    429

static const struct device_compatible_entry compat_data[] = {
        { .compat = "QCOM0C5C" },
        DEVICE_COMPAT_EOL
};

static int
qcsmptp_match(device_t parent, cfdata_t match, void *aux)
{
        struct acpi_attach_args *aa = aux;

        return acpi_compatible_match(aa, compat_data);
}

static void
qcsmptp_attach(device_t parent, device_t self, void *aux)
{
        struct qcsmptp_softc *sc = device_private(self);
        struct qcsmptp_interrupt_controller *ic;
        struct qcsmptp_entry *e;

        sc->sc_dev = self;

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

        sc->sc_ih = qcipcc_intr_establish(IPCC_CLIENT_LPASS,
            IPCC_MPROC_SIGNAL_SMP2P, IPL_VM, qcsmptp_intr, sc);
        if (sc->sc_ih == NULL) {
                aprint_error(": can't establish interrupt\n");
                return;
        }

        sc->sc_local_pid = QCSMPTP_X1E_LOCAL_PID;
        sc->sc_remote_pid = QCSMPTP_X1E_REMOTE_PID;
        sc->sc_smem_id[0] = QCSMPTP_X1E_SMEM_ID0;
        sc->sc_smem_id[1] = QCSMPTP_X1E_SMEM_ID1;

        aprint_naive("\n");
        aprint_normal("\n");

        sc->sc_ipcc = qcipcc_channel(IPCC_CLIENT_LPASS,
            IPCC_MPROC_SIGNAL_SMP2P);
        if (sc->sc_ipcc == NULL) {
                aprint_error_dev(self, "can't get mailbox\n");
                return;
        }

        if (qcsmem_alloc(sc->sc_remote_pid, sc->sc_smem_id[0],
            sizeof(*sc->sc_in)) != 0) {
                aprint_error_dev(self, "can't alloc smp2p item\n");
                return;
        }

        sc->sc_in = qcsmem_get(sc->sc_remote_pid, sc->sc_smem_id[0], NULL);
        if (sc->sc_in == NULL) {
                aprint_error_dev(self, "can't get smp2p item\n");
                return;
        }

        if (qcsmem_alloc(sc->sc_remote_pid, sc->sc_smem_id[1],
            sizeof(*sc->sc_out)) != 0) {
                aprint_error_dev(self, "can't alloc smp2p item\n");
                return;
        }

        sc->sc_out = qcsmem_get(sc->sc_remote_pid, sc->sc_smem_id[1], NULL);
        if (sc->sc_out == NULL) {
                aprint_error_dev(self, "can't get smp2p item\n");
                return;
        }

        qcsmem_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;
        qcipcc_send(sc->sc_ipcc);

        e = kmem_zalloc(sizeof(*e), KM_SLEEP);
        e->e_name = "master-kernel";
        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 */

        e = kmem_zalloc(sizeof(*e), KM_SLEEP);
        e->e_name = "slave-kernel";
        ic = kmem_zalloc(sizeof(*ic), KM_SLEEP);
        TAILQ_INIT(&ic->ic_intrq);
        ic->ic_sc = sc;
        e->e_ic = ic;
        TAILQ_INSERT_TAIL(&sc->sc_inboundq, e, e_q);

        qcsmptp_ic = ic;
}

static 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();
                qcipcc_send(sc->sc_ipcc);
        }

        return 1;
}

void *
qcsmptp_intr_establish(u_int pin, int (*func)(void *), void *arg)
{
        struct qcsmptp_interrupt_controller *ic = qcsmptp_ic;
        struct qcsmptp_intrhand *ih;

        if (ic == NULL) {
                return NULL;
        }

        ih = kmem_zalloc(sizeof(*ih), KM_SLEEP);
        ih->ih_func = func;
        ih->ih_arg = arg;
        ih->ih_ic = ic;
        ih->ih_pin = pin;
        TAILQ_INSERT_TAIL(&ic->ic_intrq, ih, ih_q);

        qcsmptp_intr_enable(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);
        kmem_free(ih, 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;
}