/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2017 Kyle Evans <kevans@FreeBSD.org>
 *
 * 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 AUTHOR 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 AUTHOR 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.
 */

/*
 * This is a generic syscon driver, whose purpose is to provide access to
 * various unrelated bits packed in a single register space. It is usually used
 * as a fallback to more specific driver, but works well enough for simple
 * access.
 */

#include <sys/cdefs.h>
#include "opt_platform.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/kobj.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/rman.h>
#include <sys/sx.h>
#include <sys/queue.h>

#include <machine/bus.h>

#ifdef FDT
#include <dev/ofw/ofw_bus.h>
#include <dev/ofw/ofw_bus_subr.h>
#endif

#include "syscon_if.h"
#include "syscon.h"

/*
 * Syscon interface details
 */
typedef TAILQ_HEAD(syscon_list, syscon) syscon_list_t;

/*
 * Declarations
 */
static int syscon_method_init(struct syscon *syscon);
static int syscon_method_uninit(struct syscon *syscon);
static uint32_t syscon_method_read_4(struct syscon *syscon, bus_size_t offset);
static int syscon_method_write_4(struct syscon *syscon, bus_size_t offset,
    uint32_t val);
static int syscon_method_modify_4(struct syscon *syscon, bus_size_t offset,
    uint32_t clear_bits, uint32_t set_bits);


MALLOC_DEFINE(M_SYSCON, "syscon", "Syscon driver");

static syscon_list_t syscon_list = TAILQ_HEAD_INITIALIZER(syscon_list);
static struct sx                syscon_topo_lock;
SX_SYSINIT(syscon_topology, &syscon_topo_lock, "Syscon topology lock");

/*
 * Syscon methods.
 */
static syscon_method_t syscon_methods[] = {
        SYSCONMETHOD(syscon_init,       syscon_method_init),
        SYSCONMETHOD(syscon_uninit,     syscon_method_uninit),
        SYSCONMETHOD(syscon_read_4,     syscon_method_read_4),
        SYSCONMETHOD(syscon_write_4,    syscon_method_write_4),
        SYSCONMETHOD(syscon_modify_4,   syscon_method_modify_4),

        SYSCONMETHOD_END
};
DEFINE_CLASS_0(syscon, syscon_class, syscon_methods, 0);

#define SYSCON_TOPO_SLOCK()     sx_slock(&syscon_topo_lock)
#define SYSCON_TOPO_XLOCK()     sx_xlock(&syscon_topo_lock)
#define SYSCON_TOPO_UNLOCK()    sx_unlock(&syscon_topo_lock)
#define SYSCON_TOPO_ASSERT()    sx_assert(&syscon_topo_lock, SA_LOCKED)
#define SYSCON_TOPO_XASSERT()   sx_assert(&syscon_topo_lock, SA_XLOCKED)

/*
 * Default syscon methods for base class.
 */
static int
syscon_method_init(struct syscon *syscon)
{

        return (0);
};

static int
syscon_method_uninit(struct syscon *syscon)
{

        return (0);
};

void *
syscon_get_softc(struct syscon *syscon)
{

        return (syscon->softc);
};

static uint32_t
syscon_method_read_4(struct syscon *syscon, bus_size_t offset)
{
        uint32_t val;

        SYSCON_DEVICE_LOCK(syscon->pdev);
        val = SYSCON_UNLOCKED_READ_4(syscon, offset);
        SYSCON_DEVICE_UNLOCK(syscon->pdev);
        return(val);
}

static int
syscon_method_write_4(struct syscon *syscon, bus_size_t offset, uint32_t val)
{
        int     rv;

        SYSCON_DEVICE_LOCK(syscon->pdev);
        rv = SYSCON_UNLOCKED_WRITE_4(syscon, offset, val);
        SYSCON_DEVICE_UNLOCK(syscon->pdev);
        return(rv);
}

static int
syscon_method_modify_4(struct syscon *syscon, bus_size_t offset,
    uint32_t clear_bits, uint32_t set_bits)
{
        int     rv;

        SYSCON_DEVICE_LOCK(syscon->pdev);
        rv = SYSCON_UNLOCKED_MODIFY_4(syscon, offset, clear_bits, set_bits);
        SYSCON_DEVICE_UNLOCK(syscon->pdev);
        return(rv);
}
/*
 * Create and initialize syscon object, but do not register it.
 */
struct syscon *
syscon_create(device_t pdev, syscon_class_t syscon_class)
{
        struct syscon *syscon;

        /* Create object and initialize it. */
        syscon = malloc(sizeof(struct syscon), M_SYSCON,
            M_WAITOK | M_ZERO);
        kobj_init((kobj_t)syscon, (kobj_class_t)syscon_class);

        /* Allocate softc if required. */
        if (syscon_class->size > 0)
                syscon->softc = malloc(syscon_class->size, M_SYSCON,
                    M_WAITOK | M_ZERO);

        /* Rest of init. */
        syscon->pdev = pdev;
        return (syscon);
}

/* Register syscon object. */
struct syscon *
syscon_register(struct syscon *syscon)
{
        int rv;

#ifdef FDT
        if (syscon->ofw_node <= 0)
                syscon->ofw_node = ofw_bus_get_node(syscon->pdev);
        if (syscon->ofw_node <= 0)
                return (NULL);
#endif

        rv = SYSCON_INIT(syscon);
        if (rv != 0) {
                printf("SYSCON_INIT failed: %d\n", rv);
                return (NULL);
        }

#ifdef FDT
        OF_device_register_xref(OF_xref_from_node(syscon->ofw_node),
            syscon->pdev);
#endif
        SYSCON_TOPO_XLOCK();
        TAILQ_INSERT_TAIL(&syscon_list, syscon, syscon_link);
        SYSCON_TOPO_UNLOCK();
        return (syscon);
}

int
syscon_unregister(struct syscon *syscon)
{

        SYSCON_TOPO_XLOCK();
        TAILQ_REMOVE(&syscon_list, syscon, syscon_link);
        SYSCON_TOPO_UNLOCK();
#ifdef FDT
        OF_device_register_xref(OF_xref_from_node(syscon->ofw_node), NULL);
#endif
        return (SYSCON_UNINIT(syscon));
}

/**
 * Provider methods
 */
#ifdef FDT
static struct syscon *
syscon_find_by_ofw_node(phandle_t node)
{
        struct syscon *entry;

        SYSCON_TOPO_ASSERT();

        TAILQ_FOREACH(entry, &syscon_list, syscon_link) {
                if (entry->ofw_node == node)
                        return (entry);
        }

        return (NULL);
}

struct syscon *
syscon_create_ofw_node(device_t pdev, syscon_class_t syscon_class,
    phandle_t node)
{
        struct syscon *syscon;

        syscon = syscon_create(pdev, syscon_class);
        if (syscon == NULL)
                return (NULL);
        syscon->ofw_node = node;
        if (syscon_register(syscon) == NULL)
                return (NULL);
        return (syscon);
}

phandle_t
syscon_get_ofw_node(struct syscon *syscon)
{

        return (syscon->ofw_node);
}

int
syscon_get_by_ofw_node(device_t cdev, phandle_t node, struct syscon **syscon)
{

        SYSCON_TOPO_SLOCK();
        *syscon = syscon_find_by_ofw_node(node);
        if (*syscon == NULL) {
                SYSCON_TOPO_UNLOCK();
                device_printf(cdev, "Failed to find syscon node\n");
                return (ENODEV);
        }
        SYSCON_TOPO_UNLOCK();
        return (0);
}

int
syscon_get_by_ofw_property(device_t cdev, phandle_t cnode, char *name,
    struct syscon **syscon)
{
        pcell_t *cells;
        int ncells;

        if (cnode <= 0)
                cnode = ofw_bus_get_node(cdev);
        if (cnode <= 0) {
                device_printf(cdev,
                    "%s called on not ofw based device\n", __func__);
                return (ENXIO);
        }
        ncells = OF_getencprop_alloc_multi(cnode, name, sizeof(pcell_t),
            (void **)&cells);
        if (ncells < 1)
                return (ENOENT);

        /* Translate to syscon node. */
        SYSCON_TOPO_SLOCK();
        *syscon = syscon_find_by_ofw_node(OF_node_from_xref(cells[0]));
        if (*syscon == NULL) {
                SYSCON_TOPO_UNLOCK();
                device_printf(cdev, "Failed to find syscon node\n");
                OF_prop_free(cells);
                return (ENODEV);
        }
        SYSCON_TOPO_UNLOCK();
        OF_prop_free(cells);
        return (0);
}
#endif