/*-
 * Copyright 1998 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. 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.
 *
 */

/*
 * This code implements a `root nexus' for RISC-V Architecture
 * machines.  The function of the root nexus is to serve as an
 * attachment point for both processors and buses, and to manage
 * resources which are common to all of them.  In particular,
 * this code implements the core resource managers for interrupt
 * requests and I/O memory address space.
 */
#include "opt_platform.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/interrupt.h>

#include <vm/vm.h>
#include <vm/pmap.h>

#include <machine/bus.h>
#include <machine/resource.h>
#include <machine/intr.h>

#ifdef FDT
#include <dev/ofw/ofw_bus_subr.h>
#include <dev/ofw/openfirm.h>
#include "ofw_bus_if.h"
#endif

extern struct bus_space memmap_bus;

static MALLOC_DEFINE(M_NEXUSDEV, "nexusdev", "Nexus device");

struct nexus_device {
        struct resource_list    nx_resources;
};

#define DEVTONX(dev)    ((struct nexus_device *)device_get_ivars(dev))

static struct rman mem_rman;
static struct rman irq_rman;

static device_probe_t           nexus_fdt_probe;
static device_attach_t          nexus_attach;

static bus_add_child_t          nexus_add_child;
static bus_print_child_t        nexus_print_child;

static bus_activate_resource_t  nexus_activate_resource;
static bus_alloc_resource_t     nexus_alloc_resource;
static bus_deactivate_resource_t nexus_deactivate_resource;
static bus_get_resource_list_t  nexus_get_reslist;
static bus_get_rman_t           nexus_get_rman;
static bus_map_resource_t       nexus_map_resource;
static bus_unmap_resource_t     nexus_unmap_resource;

static bus_config_intr_t        nexus_config_intr;
static bus_describe_intr_t      nexus_describe_intr;
static bus_setup_intr_t         nexus_setup_intr;
static bus_teardown_intr_t      nexus_teardown_intr;

static bus_get_bus_tag_t        nexus_get_bus_tag;

static ofw_bus_map_intr_t       nexus_ofw_map_intr;

static device_method_t nexus_methods[] = {
        /* Device interface */
        DEVMETHOD(device_probe,         nexus_fdt_probe),
        DEVMETHOD(device_attach,        nexus_attach),
        DEVMETHOD(device_shutdown,      bus_generic_shutdown),

        /* OFW interface */
        DEVMETHOD(ofw_bus_map_intr,     nexus_ofw_map_intr),

        /* Bus interface */
        DEVMETHOD(bus_add_child,        nexus_add_child),
        DEVMETHOD(bus_print_child,      nexus_print_child),
        DEVMETHOD(bus_activate_resource, nexus_activate_resource),
        DEVMETHOD(bus_adjust_resource,  bus_generic_rman_adjust_resource),
        DEVMETHOD(bus_alloc_resource,   nexus_alloc_resource),
        DEVMETHOD(bus_deactivate_resource, nexus_deactivate_resource),
        DEVMETHOD(bus_delete_resource,  bus_generic_rl_delete_resource),
        DEVMETHOD(bus_get_resource,     bus_generic_rl_get_resource),
        DEVMETHOD(bus_get_resource_list, nexus_get_reslist),
        DEVMETHOD(bus_get_rman,         nexus_get_rman),
        DEVMETHOD(bus_map_resource,     nexus_map_resource),
        DEVMETHOD(bus_release_resource, bus_generic_rman_release_resource),
        DEVMETHOD(bus_set_resource,     bus_generic_rl_set_resource),
        DEVMETHOD(bus_unmap_resource,   nexus_unmap_resource),
        DEVMETHOD(bus_config_intr,      nexus_config_intr),
        DEVMETHOD(bus_describe_intr,    nexus_describe_intr),
        DEVMETHOD(bus_setup_intr,       nexus_setup_intr),
        DEVMETHOD(bus_teardown_intr,    nexus_teardown_intr),
        DEVMETHOD(bus_get_bus_tag,      nexus_get_bus_tag),

        DEVMETHOD_END
};

static driver_t nexus_fdt_driver = {
        "nexus",
        nexus_methods,
        1                       /* no softc */
};

EARLY_DRIVER_MODULE(nexus_fdt, root, nexus_fdt_driver, 0, 0,
    BUS_PASS_BUS + BUS_PASS_ORDER_FIRST);

static int
nexus_fdt_probe(device_t dev)
{

        device_quiet(dev);
        return (BUS_PROBE_DEFAULT);
}

static int
nexus_attach(device_t dev)
{

        mem_rman.rm_start = 0;
        mem_rman.rm_end = BUS_SPACE_MAXADDR;
        mem_rman.rm_type = RMAN_ARRAY;
        mem_rman.rm_descr = "I/O memory addresses";
        if (rman_init(&mem_rman) ||
            rman_manage_region(&mem_rman, 0, BUS_SPACE_MAXADDR))
                panic("nexus_attach mem_rman");
        irq_rman.rm_start = 0;
        irq_rman.rm_end = ~0;
        irq_rman.rm_type = RMAN_ARRAY;
        irq_rman.rm_descr = "Interrupts";
        if (rman_init(&irq_rman) || rman_manage_region(&irq_rman, 0, ~0))
                panic("nexus_attach irq_rman");

        /*
         * Add direct children of nexus. Devices will be probed and attached
         * through ofwbus0.
         */
        nexus_add_child(dev, 0, "timer", 0);
        nexus_add_child(dev, 1, "rcons", 0);
        nexus_add_child(dev, 2, "ofwbus", 0);

        bus_identify_children(dev);
        bus_attach_children(dev);

        return (0);
}

static int
nexus_print_child(device_t bus, device_t child)
{
        int retval = 0;

        retval += bus_print_child_header(bus, child);
        retval += printf("\n");

        return (retval);
}

static device_t
nexus_add_child(device_t bus, u_int order, const char *name, int unit)
{
        device_t child;
        struct nexus_device *ndev;

        ndev = malloc(sizeof(struct nexus_device), M_NEXUSDEV, M_NOWAIT|M_ZERO);
        if (!ndev)
                return (0);
        resource_list_init(&ndev->nx_resources);

        child = device_add_child_ordered(bus, order, name, unit);

        device_set_ivars(child, ndev);

        return (child);
}

static struct rman *
nexus_get_rman(device_t bus, int type, u_int flags)
{

        switch (type) {
        case SYS_RES_IRQ:
                return (&irq_rman);
        case SYS_RES_MEMORY:
                return (&mem_rman);
        default:
                return (NULL);
        }
}

/*
 * Allocate a resource on behalf of child.  NB: child is usually going to be a
 * child of one of our descendants, not a direct child of nexus0.
 */
static struct resource *
nexus_alloc_resource(device_t bus, device_t child, int type, int rid,
    rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
{
        struct nexus_device *ndev = DEVTONX(child);
        struct resource_list_entry *rle;

        /*
         * If this is an allocation of the "default" range for a given
         * RID, and we know what the resources for this device are
         * (ie. they aren't maintained by a child bus), then work out
         * the start/end values.
         */
        if (RMAN_IS_DEFAULT_RANGE(start, end) && (count == 1)) {
                if (device_get_parent(child) != bus || ndev == NULL)
                        return (NULL);
                rle = resource_list_find(&ndev->nx_resources, type, rid);
                if (rle == NULL)
                        return (NULL);
                start = rle->start;
                end = rle->end;
                count = rle->count;
        }

        return (bus_generic_rman_alloc_resource(bus, child, type, rid,
            start, end, count, flags));
}

static int
nexus_config_intr(device_t dev, int irq, enum intr_trigger trig,
    enum intr_polarity pol)
{

        return (EOPNOTSUPP);
}

static int
nexus_setup_intr(device_t dev, device_t child, struct resource *res, int flags,
    driver_filter_t *filt, driver_intr_t *intr, void *arg, void **cookiep)
{
        int error;

        if ((rman_get_flags(res) & RF_SHAREABLE) == 0)
                flags |= INTR_EXCL;

        /* We depend here on rman_activate_resource() being idempotent. */
        error = rman_activate_resource(res);
        if (error != 0)
                return (error);

        error = intr_setup_irq(child, res, filt, intr, arg, flags, cookiep);

        return (error);
}

static int
nexus_teardown_intr(device_t dev, device_t child, struct resource *r, void *ih)
{

        return (intr_teardown_irq(child, r, ih));
}

static int
nexus_describe_intr(device_t dev, device_t child, struct resource *irq,
    void *cookie, const char *descr)
{

        return (intr_describe_irq(child, irq, cookie, descr));
}

static bus_space_tag_t
nexus_get_bus_tag(device_t bus __unused, device_t child __unused)
{

        return (&memmap_bus);
}

static int
nexus_activate_resource(device_t bus, device_t child, struct resource *r)
{
        int error;

        switch (rman_get_type(r)) {
        case SYS_RES_MEMORY:
                error = bus_generic_rman_activate_resource(bus, child, r);
                break;
        case SYS_RES_IRQ:
                error = rman_activate_resource(r);
                if (error != 0)
                        return (error);
                error = intr_activate_irq(child, r);
                if (error != 0) {
                        rman_deactivate_resource(r);
                        return (error);
                }
                break;
        default:
                error = EINVAL;
                break;
        }
        return (error);
}

static struct resource_list *
nexus_get_reslist(device_t dev, device_t child)
{
        struct nexus_device *ndev = DEVTONX(child);

        return (&ndev->nx_resources);
}

static int
nexus_deactivate_resource(device_t bus, device_t child, struct resource *r)
{
        int error;

        switch (rman_get_type(r)) {
        case SYS_RES_MEMORY:
                error = bus_generic_rman_deactivate_resource(bus, child, r);
                break;
        case SYS_RES_IRQ:
                error = rman_deactivate_resource(r);
                if (error != 0)
                        return (error);
                intr_deactivate_irq(child, r);
                break;
        default:
                error = EINVAL;
                break;
        }
        return (error);
}

static int
nexus_map_resource(device_t bus, device_t child, struct resource *r,
    struct resource_map_request *argsp, struct resource_map *map)
{
        struct resource_map_request args;
        rman_res_t length, start;
        int error;

        /* Resources must be active to be mapped. */
        if ((rman_get_flags(r) & RF_ACTIVE) == 0)
                return (ENXIO);

        /* Mappings are only supported on memory resources. */
        switch (rman_get_type(r)) {
        case SYS_RES_MEMORY:
                break;
        default:
                return (EINVAL);
        }

        resource_init_map_request(&args);
        error = resource_validate_map_request(r, argsp, &args, &start, &length);
        if (error)
                return (error);

        map->r_vaddr = pmap_mapdev(start, length);
        map->r_bustag = &memmap_bus;
        map->r_size = length;

        /*
         * The handle is the virtual address.
         */
        map->r_bushandle = (bus_space_handle_t)map->r_vaddr;
        return (0);
}

static int
nexus_unmap_resource(device_t bus, device_t child, struct resource *r,
    struct resource_map *map)
{
        switch (rman_get_type(r)) {
        case SYS_RES_MEMORY:
                pmap_unmapdev(map->r_vaddr, map->r_size);
                return (0);
        default:
                return (EINVAL);
        }
}

static int
nexus_ofw_map_intr(device_t dev, device_t child, phandle_t iparent, int icells,
    pcell_t *intr)
{
        struct intr_map_data_fdt *fdt_data;
        size_t len;
        u_int irq;

        len = sizeof(*fdt_data) + icells * sizeof(pcell_t);
        fdt_data = (struct intr_map_data_fdt *)intr_alloc_map_data(
            INTR_MAP_DATA_FDT, len, M_WAITOK | M_ZERO);
        fdt_data->iparent = iparent;
        fdt_data->ncells = icells;
        memcpy(fdt_data->cells, intr, icells * sizeof(pcell_t));
        irq = intr_map_irq(NULL, iparent, (struct intr_map_data *)fdt_data);

        return (irq);
}