/* $NetBS$ */
/*      $OpenBSD: qcipcc.c,v 1.2 2023/05/19 20:54:55 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/acpi_intr.h>
#include <dev/acpi/qcomipcc.h>

#define IPCC_SEND_ID                    0x0c
#define IPCC_RECV_ID                    0x10
#define IPCC_RECV_SIGNAL_ENABLE         0x14
#define IPCC_RECV_SIGNAL_DISABLE        0x18
#define IPCC_RECV_SIGNAL_CLEAR          0x1c

#define IPCC_SIGNAL_ID_MASK             __BITS(15,0)
#define IPCC_CLIENT_ID_MASK             __BITS(31,16)

#define HREAD4(sc, reg)                                                 \
        bus_space_read_4((sc)->sc_iot, (sc)->sc_ioh, (reg))
#define HWRITE4(sc, reg, val)                                           \
        bus_space_write_4((sc)->sc_iot, (sc)->sc_ioh, (reg), (val))

struct qcipcc_intrhand {
        TAILQ_ENTRY(qcipcc_intrhand) ih_q;
        int (*ih_func)(void *);
        void *ih_arg;
        void *ih_sc;
        uint32_t ih_client_id;
        uint32_t ih_signal_id;
};

struct qcipcc_softc {
        device_t                sc_dev;
        bus_space_tag_t         sc_iot;
        bus_space_handle_t      sc_ioh;

        void                    *sc_ih;

        TAILQ_HEAD(,qcipcc_intrhand) sc_intrq;
};

static struct qcipcc_softc *qcipcc = NULL;

struct qcipcc_channel {
        struct qcipcc_softc     *ch_sc;
        uint32_t                ch_client_id;
        uint32_t                ch_signal_id;
};

#define QCIPCC_8380_BASE        0x00408000
#define QCIPCC_SIZE             0x1000

static const struct device_compatible_entry compat_data[] = {
        { .compat = "QCOM06C2",         .value = QCIPCC_8380_BASE },
        DEVICE_COMPAT_EOL
};

static int      qcipcc_match(device_t, cfdata_t, void *);
static void     qcipcc_attach(device_t, device_t, void *);
static int      qcipcc_intr(void *);

CFATTACH_DECL_NEW(qcomipcc, sizeof(struct qcipcc_softc),
    qcipcc_match, qcipcc_attach, NULL, NULL);

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

        return acpi_compatible_match(aa, compat_data);
}

static void
qcipcc_attach(device_t parent, device_t self, void *aux)
{
        struct qcipcc_softc *sc = device_private(self);
        struct acpi_attach_args *aa = aux;
        ACPI_HANDLE hdl;
        struct acpi_resources res;
        struct acpi_irq *irq;
        bus_addr_t base_addr;
        ACPI_STATUS rv;

        if (qcipcc != NULL) {
                aprint_error(": already attached!\n");
                return;
        }

        hdl = aa->aa_node->ad_handle;
        rv = acpi_resource_parse(self, hdl, "_CRS", &res,
            &acpi_resource_parse_ops_default);
        if (ACPI_FAILURE(rv)) {
                return;
        }

        irq = acpi_res_irq(&res, 0);
        if (irq == NULL) {
                aprint_error_dev(self, "couldn't find irq resource\n");
                goto done;
        }

        base_addr = acpi_compatible_lookup(aa, compat_data)->value;

        sc->sc_dev = self;
        sc->sc_iot = aa->aa_memt;
        if (bus_space_map(sc->sc_iot, base_addr, QCIPCC_SIZE,
            BUS_SPACE_MAP_NONPOSTED, &sc->sc_ioh) != 0) {
                aprint_error_dev(self, "couldn't map registers\n");
                goto done;
        }

        TAILQ_INIT(&sc->sc_intrq);

        sc->sc_ih = acpi_intr_establish(self,
            (uint64_t)(uintptr_t)hdl,
            IPL_VM, false, qcipcc_intr, sc, device_xname(self));
        if (sc->sc_ih == NULL) {
                aprint_error_dev(self,
                    "couldn't establish interrupt\n");
                goto done;
        }

        qcipcc = sc;

done:
        acpi_resource_cleanup(&res);
}

static int
qcipcc_intr(void *arg)
{
        struct qcipcc_softc *sc = arg;
        struct qcipcc_intrhand *ih;
        uint16_t client_id, signal_id;
        uint32_t reg;
        int handled = 0;

        while ((reg = HREAD4(sc, IPCC_RECV_ID)) != ~0) {
                HWRITE4(sc, IPCC_RECV_SIGNAL_CLEAR, reg);

                client_id = __SHIFTOUT(reg, IPCC_CLIENT_ID_MASK);
                signal_id = __SHIFTOUT(reg, IPCC_SIGNAL_ID_MASK);

                TAILQ_FOREACH(ih, &sc->sc_intrq, ih_q) {
                        if (ih->ih_client_id != client_id ||
                            ih->ih_signal_id != signal_id)
                                continue;
                        ih->ih_func(ih->ih_arg);
                        handled = 1;
                }
        }

        return handled;
}

void *
qcipcc_intr_establish(uint16_t client_id, uint16_t signal_id, int ipl,
    int (*func)(void *), void *arg)
{
        struct qcipcc_softc *sc = qcipcc;
        struct qcipcc_intrhand *ih;

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

        ih = kmem_zalloc(sizeof(*ih), KM_SLEEP);
        ih->ih_func = func;
        ih->ih_arg = arg;
        ih->ih_sc = sc;
        ih->ih_client_id = client_id;
        ih->ih_signal_id = signal_id;
        TAILQ_INSERT_TAIL(&sc->sc_intrq, ih, ih_q);

        qcipcc_intr_enable(ih);

        return ih;
}

void
qcipcc_intr_disestablish(void *cookie)
{
        struct qcipcc_intrhand *ih = cookie;
        struct qcipcc_softc *sc = ih->ih_sc;

        qcipcc_intr_disable(ih);

        TAILQ_REMOVE(&sc->sc_intrq, ih, ih_q);
        kmem_free(ih, sizeof(*ih));
}

void
qcipcc_intr_enable(void *cookie)
{
        struct qcipcc_intrhand *ih = cookie;
        struct qcipcc_softc *sc = ih->ih_sc;

        HWRITE4(sc, IPCC_RECV_SIGNAL_ENABLE,
            __SHIFTIN(ih->ih_client_id, IPCC_CLIENT_ID_MASK) |
            __SHIFTIN(ih->ih_signal_id, IPCC_SIGNAL_ID_MASK));
}

void
qcipcc_intr_disable(void *cookie)
{
        struct qcipcc_intrhand *ih = cookie;
        struct qcipcc_softc *sc = ih->ih_sc;

        HWRITE4(sc, IPCC_RECV_SIGNAL_DISABLE,
            __SHIFTIN(ih->ih_client_id, IPCC_CLIENT_ID_MASK) |
            __SHIFTIN(ih->ih_signal_id, IPCC_SIGNAL_ID_MASK));
}

void *
qcipcc_channel(uint16_t client_id, uint16_t signal_id)
{
        struct qcipcc_softc *sc = qcipcc;
        struct qcipcc_channel *ch;

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

        ch = kmem_zalloc(sizeof(*ch), KM_SLEEP);
        ch->ch_sc = sc;
        ch->ch_client_id = client_id;
        ch->ch_signal_id = signal_id;

        return ch;
}

int
qcipcc_send(void *cookie)
{
        struct qcipcc_channel *ch = cookie;
        struct qcipcc_softc *sc = ch->ch_sc;

        HWRITE4(sc, IPCC_SEND_ID,
            __SHIFTIN(ch->ch_client_id, IPCC_CLIENT_ID_MASK) |
            __SHIFTIN(ch->ch_signal_id, IPCC_SIGNAL_ID_MASK));

        return 0;
}