/*      $NetBSD: exynos_combiner.c,v 1.14 2021/03/14 08:16:57 skrll Exp $ */

/*-
* Copyright (c) 2015 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Marty Fouts
*
* 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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``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 FOUNDATION OR CONTRIBUTORS
* 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 "opt_exynos.h"
#include "opt_arm_debug.h"
#include "opt_multiprocessor.h"
#include "gpio.h"

#include <sys/cdefs.h>
__KERNEL_RCSID(1, "$NetBSD: exynos_combiner.c,v 1.14 2021/03/14 08:16:57 skrll Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/device.h>
#include <sys/intr.h>
#include <sys/systm.h>
#include <sys/kmem.h>

#include <arm/cortex/gic_intr.h>

#include <arm/samsung/exynos_reg.h>
#include <arm/samsung/exynos_intr.h>

#include <dev/fdt/fdtvar.h>

#define COMBINER_GROUP_BASE(group)      (((group) / 4) * 0x10)
#define COMBINER_GROUP_MASK(group)      (0xff << (((group) % 4) * 8))

#define COMBINER_IESR_REG(group)        (COMBINER_GROUP_BASE(group) + 0x00)
#define COMBINER_IECR_REG(group)        (COMBINER_GROUP_BASE(group) + 0x04)
#define COMBINER_ISTR_REG(group)        (COMBINER_GROUP_BASE(group) + 0x08)
#define COMBINER_IMSR_REG(group)        (COMBINER_GROUP_BASE(group) + 0x0c)

struct exynos_combiner_softc;

struct exynos_combiner_irq_entry {
        int                             irq_no;
        int (*irq_handler)(void *);
        void *                          irq_arg;
        struct exynos_combiner_irq_entry *irq_next;
        bool                            irq_mpsafe;
};

struct exynos_combiner_irq_group {
        int irq_group_no;
        struct exynos_combiner_softc    *irq_sc;
        struct exynos_combiner_irq_entry *irq_entries;
        struct exynos_combiner_irq_group *irq_group_next;
        void *irq_ih;
        int irq_ipl;
};

struct exynos_combiner_softc {
        device_t                sc_dev;
        bus_space_tag_t         sc_bst;
        bus_space_handle_t      sc_bsh;
        int                     sc_phandle;
        struct exynos_combiner_irq_group *irq_groups;
};

static int exynos_combiner_match(device_t, cfdata_t, void *);
static void exynos_combiner_attach(device_t, device_t, void *);

static void *   exynos_combiner_establish(device_t, u_int *, int, int,
                    int (*)(void *), void *, const char *);
static void     exynos_combiner_disestablish(device_t, void *);
static bool     exynos_combiner_intrstr(device_t, u_int  *, char *,
                                        size_t);

struct fdtbus_interrupt_controller_func exynos_combiner_funcs = {
        .establish = exynos_combiner_establish,
        .disestablish = exynos_combiner_disestablish,
        .intrstr = exynos_combiner_intrstr
};

CFATTACH_DECL_NEW(exynos_intr, sizeof(struct exynos_combiner_softc),
        exynos_combiner_match, exynos_combiner_attach, NULL, NULL);

static const struct device_compatible_entry compat_data[] = {
        { .compat = "samsung,exynos4210-combiner" },
        DEVICE_COMPAT_EOL
};

static int
exynos_combiner_match(device_t parent, cfdata_t cf, void *aux)
{
        struct fdt_attach_args * const faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
exynos_combiner_attach(device_t parent, device_t self, void *aux)
{
        struct exynos_combiner_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        bus_addr_t addr;
        bus_size_t size;
        int error;

        if (fdtbus_get_reg(faa->faa_phandle, 0, &addr, &size) != 0) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        sc->sc_dev = self;
        sc->sc_phandle = faa->faa_phandle;
        sc->sc_bst = faa->faa_bst;

        error = bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh);
        if (error) {
                aprint_error(": couldn't map %#" PRIxBUSADDR ": %d",
                             addr, error);
                return;
        }

        error = fdtbus_register_interrupt_controller(self, faa->faa_phandle,
            &exynos_combiner_funcs);
        if (error) {
                aprint_error(": couldn't register with fdtbus: %d\n", error);
                return;
        }

        aprint_naive("\n");
        aprint_normal(" @ 0x%08x: interrupt combiner\n", (uint)addr);

}

static struct exynos_combiner_irq_group *
exynos_combiner_new_group(struct exynos_combiner_softc *sc, int group_no)
{
        struct exynos_combiner_irq_group *n = kmem_zalloc(sizeof(*n),
                                                          KM_SLEEP);
        n->irq_group_no = group_no;
        n->irq_group_next = sc->irq_groups;
        n->irq_sc = sc;
        sc->irq_groups = n;
        return n;
}

static struct exynos_combiner_irq_group *
exynos_combiner_get_group(struct exynos_combiner_softc *sc, int group_no)
{
        for (struct exynos_combiner_irq_group *g = sc->irq_groups;
             g; g = g->irq_group_next) {
                if (g->irq_group_no == group_no)
                        return g;
        }
        return NULL;
}

static struct exynos_combiner_irq_entry *
exynos_combiner_new_irq(struct exynos_combiner_irq_group *group,
                        int irq, bool mpsafe, int (*func)(void *), void *arg)
{
        struct exynos_combiner_irq_entry * n = kmem_zalloc(sizeof(*n),
                                                           KM_SLEEP);
        n->irq_no = irq;
        n->irq_handler = func;
        n->irq_next = group->irq_entries;
        n->irq_arg = arg;
        n->irq_mpsafe = mpsafe;
        group->irq_entries = n;
        return n;
}

static struct exynos_combiner_irq_entry *
exynos_combiner_get_irq(struct exynos_combiner_irq_group *g, int irq)
{
        for (struct exynos_combiner_irq_entry *p = g->irq_entries; p;
             p = p->irq_next) {
                if (p->irq_no == irq)
                        return p;
        }
        return NULL;
}

static int
exynos_combiner_irq(void *cookie)
{
        struct exynos_combiner_irq_group *groupp = cookie;
        struct exynos_combiner_softc *sc = groupp->irq_sc;
        int rv = 0;

        const int group_no = groupp->irq_group_no;

        const uint32_t istr =
            bus_space_read_4(sc->sc_bst, sc->sc_bsh, COMBINER_ISTR_REG(group_no));
        const uint32_t istatus = __SHIFTOUT(istr, COMBINER_GROUP_MASK(group_no));

        for (int irq = 0; irq < 8; irq++) {
                if (istatus & __BIT(irq)) {
                        struct exynos_combiner_irq_entry *e =
                                exynos_combiner_get_irq(groupp, irq);
                        if (e) {
                                if (!e->irq_mpsafe)
                                        KERNEL_LOCK(1, curlwp);
                                rv += e->irq_handler(e->irq_arg);
                                if (!e->irq_mpsafe)
                                        KERNEL_UNLOCK_ONE(curlwp);
                        } else
                                printf("%s: Unexpected irq (%d) on group %d\n", __func__,
                                       irq, group_no);
                }
        }

        return !!rv;
}

static void *
exynos_combiner_establish(device_t dev, u_int *specifier,
                          int ipl, int flags,
                          int (*func)(void *), void *arg, const char *xname)
{
        struct exynos_combiner_softc * const sc = device_private(dev);
        struct exynos_combiner_irq_group *groupp;
        struct exynos_combiner_irq_entry *entryp;
        const bool mpsafe = (flags & FDT_INTR_MPSAFE) != 0;
        uint32_t iesr;

        const u_int group = be32toh(specifier[0]);
        const u_int intr = be32toh(specifier[1]);

        groupp = exynos_combiner_get_group(sc, group);
        if (!groupp) {
                groupp = exynos_combiner_new_group(sc, group);
                if (arg == NULL) {
                        groupp->irq_ih = fdtbus_intr_establish_xname(
                            sc->sc_phandle, group, ipl /* XXX */, flags, func, NULL,
                            device_xname(dev));
                } else {
                        groupp->irq_ih = fdtbus_intr_establish_xname(
                            sc->sc_phandle,  group, ipl /* XXX */, FDT_INTR_MPSAFE,
                            exynos_combiner_irq, groupp, device_xname(dev));
                }
                KASSERT(groupp->irq_ih != NULL);
                groupp->irq_ipl = ipl;
        } else if (groupp->irq_ipl != ipl) {
                aprint_error_dev(dev,
                    "interrupt combiner cannot share interrupts with different ipl\n");
                return NULL;
        }

        if (exynos_combiner_get_irq(groupp, intr) != NULL)
                return NULL;

        entryp = exynos_combiner_new_irq(groupp, intr, mpsafe, func, arg);

        iesr = bus_space_read_4(sc->sc_bst, sc->sc_bsh, COMBINER_IESR_REG(group));
        iesr |= __SHIFTIN((1 << intr), COMBINER_GROUP_MASK(group));
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, COMBINER_IESR_REG(group), iesr);

        return entryp;
}

static void
exynos_combiner_disestablish(device_t dev, void *ih)
{
        /* MJF: Find the ih and disable the handler. */
        panic("exynos_combiner_disestablish not implemented");
}

static bool
exynos_combiner_intrstr(device_t dev, u_int *specifier, char *buf,
                        size_t buflen)
{

        /* 1st cell is the combiner group number */
        /* 2nd cell is the interrupt number within the group */

        const u_int group = be32toh(specifier[0]);
        const u_int intr = be32toh(specifier[1]);

        snprintf(buf, buflen, "interrupt combiner group %d intr %d", group, intr);

        return true;
}