/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2011 The FreeBSD Foundation
 *
 * This software was developed by Konstantin Belousov under sponsorship from
 * the FreeBSD Foundation.
 *
 * 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.
 */

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

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>

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

#include <dev/drm2/drmP.h>
#include <dev/drm2/drm.h>
#include <dev/drm2/drm_sarea.h>

/*
 * We make up offsets for buffer objects so we can recognize them at
 * mmap time.
 */

/* pgoff in mmap is an unsigned long, so we need to make sure that
 * the faked up offset will fit
 */

#if BITS_PER_LONG == 64
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFFUL >> PAGE_SHIFT) * 16)
#else
#define DRM_FILE_PAGE_OFFSET_START ((0xFFFFFFFUL >> PAGE_SHIFT) + 1)
#define DRM_FILE_PAGE_OFFSET_SIZE ((0xFFFFFFFUL >> PAGE_SHIFT) * 16)
#endif

/**
 * Initialize the GEM device fields
 */

int
drm_gem_init(struct drm_device *dev)
{
        struct drm_gem_mm *mm;

        drm_gem_names_init(&dev->object_names);

        mm = malloc(sizeof(*mm), DRM_MEM_DRIVER, M_NOWAIT);
        if (!mm) {
                DRM_ERROR("out of memory\n");
                return -ENOMEM;
        }

        dev->mm_private = mm;

        if (drm_ht_create(&mm->offset_hash, 19)) {
                free(mm, DRM_MEM_DRIVER);
                return -ENOMEM;
        }

        mm->idxunr = new_unrhdr(0, DRM_GEM_MAX_IDX, NULL);

        return 0;
}

void
drm_gem_destroy(struct drm_device *dev)
{
        struct drm_gem_mm *mm = dev->mm_private;

        dev->mm_private = NULL;
        drm_ht_remove(&mm->offset_hash);
        delete_unrhdr(mm->idxunr);
        free(mm, DRM_MEM_DRIVER);
        drm_gem_names_fini(&dev->object_names);
}

int drm_gem_object_init(struct drm_device *dev,
                        struct drm_gem_object *obj, size_t size)
{
        KASSERT((size & (PAGE_SIZE - 1)) == 0,
            ("Bad size %ju", (uintmax_t)size));

        obj->dev = dev;
        obj->vm_obj = vm_pager_allocate(OBJT_SWAP, NULL, size,
            VM_PROT_READ | VM_PROT_WRITE, 0, curthread->td_ucred);

        obj->refcount = 1;
        obj->handle_count = 0;
        obj->size = size;

        return 0;
}
EXPORT_SYMBOL(drm_gem_object_init);

/**
 * Initialize an already allocated GEM object of the specified size with
 * no GEM provided backing store. Instead the caller is responsible for
 * backing the object and handling it.
 */
int drm_gem_private_object_init(struct drm_device *dev,
                        struct drm_gem_object *obj, size_t size)
{
        MPASS((size & (PAGE_SIZE - 1)) == 0);

        obj->dev = dev;
        obj->vm_obj = NULL;

        obj->refcount = 1;
        atomic_store_rel_int(&obj->handle_count, 0);
        obj->size = size;

        return 0;
}
EXPORT_SYMBOL(drm_gem_private_object_init);

struct drm_gem_object *
drm_gem_object_alloc(struct drm_device *dev, size_t size)
{
        struct drm_gem_object *obj;

        obj = malloc(sizeof(*obj), DRM_MEM_DRIVER, M_NOWAIT | M_ZERO);
        if (!obj)
                goto free;

        if (drm_gem_object_init(dev, obj, size) != 0)
                goto free;

        if (dev->driver->gem_init_object != NULL &&
            dev->driver->gem_init_object(obj) != 0) {
                goto dealloc;
        }
        return obj;
dealloc:
        vm_object_deallocate(obj->vm_obj);
free:
        free(obj, DRM_MEM_DRIVER);
        return NULL;
}
EXPORT_SYMBOL(drm_gem_object_alloc);

#if defined(FREEBSD_NOTYET)
static void
drm_gem_remove_prime_handles(struct drm_gem_object *obj, struct drm_file *filp)
{
        if (obj->import_attach) {
                drm_prime_remove_buf_handle(&filp->prime,
                                obj->import_attach->dmabuf);
        }
        if (obj->export_dma_buf) {
                drm_prime_remove_buf_handle(&filp->prime,
                                obj->export_dma_buf);
        }
}
#endif

/**
 * Removes the mapping from handle to filp for this object.
 */
int
drm_gem_handle_delete(struct drm_file *filp, u32 handle)
{
        struct drm_device *dev;
        struct drm_gem_object *obj;

        obj = drm_gem_names_remove(&filp->object_names, handle);
        if (obj == NULL) {
                return -EINVAL;
        }
        dev = obj->dev;

#if defined(FREEBSD_NOTYET)
        drm_gem_remove_prime_handles(obj, filp);
#endif

        if (dev->driver->gem_close_object)
                dev->driver->gem_close_object(obj, filp);
        drm_gem_object_handle_unreference_unlocked(obj);

        return 0;
}
EXPORT_SYMBOL(drm_gem_handle_delete);

/**
 * Create a handle for this object. This adds a handle reference
 * to the object, which includes a regular reference count. Callers
 * will likely want to dereference the object afterwards.
 */
int
drm_gem_handle_create(struct drm_file *file_priv,
                       struct drm_gem_object *obj,
                       u32 *handlep)
{
        struct drm_device *dev = obj->dev;
        int ret;

        *handlep = 0;
        ret = drm_gem_name_create(&file_priv->object_names, obj, handlep);
        if (ret != 0)
                return ret;

        drm_gem_object_handle_reference(obj);

        if (dev->driver->gem_open_object) {
                ret = dev->driver->gem_open_object(obj, file_priv);
                if (ret) {
                        drm_gem_handle_delete(file_priv, *handlep);
                        return ret;
                }
        }

        return 0;
}
EXPORT_SYMBOL(drm_gem_handle_create);

void
drm_gem_free_mmap_offset(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;
        struct drm_gem_mm *mm = dev->mm_private;
        struct drm_hash_item *list = &obj->map_list;

        if (!obj->on_map)
                return;

        drm_ht_remove_item(&mm->offset_hash, list);
        free_unr(mm->idxunr, list->key);
        obj->on_map = false;
}
EXPORT_SYMBOL(drm_gem_free_mmap_offset);

int
drm_gem_create_mmap_offset(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;
        struct drm_gem_mm *mm = dev->mm_private;
        int ret;

        if (obj->on_map)
                return 0;

        obj->map_list.key = alloc_unr(mm->idxunr);
        ret = drm_ht_insert_item(&mm->offset_hash, &obj->map_list);
        if (ret) {
                DRM_ERROR("failed to add to map hash\n");
                free_unr(mm->idxunr, obj->map_list.key);
                return ret;
        }
        obj->on_map = true;

        return 0;
}
EXPORT_SYMBOL(drm_gem_create_mmap_offset);

/** Returns a reference to the object named by the handle. */
struct drm_gem_object *
drm_gem_object_lookup(struct drm_device *dev, struct drm_file *filp,
                      u32 handle)
{
        struct drm_gem_object *obj;

        obj = drm_gem_name_ref(&filp->object_names, handle,
            (void (*)(void *))drm_gem_object_reference);

        return obj;
}
EXPORT_SYMBOL(drm_gem_object_lookup);

int
drm_gem_close_ioctl(struct drm_device *dev, void *data,
                    struct drm_file *file_priv)
{
        struct drm_gem_close *args = data;
        int ret;

        if (!(dev->driver->driver_features & DRIVER_GEM))
                return -ENODEV;

        ret = drm_gem_handle_delete(file_priv, args->handle);

        return ret;
}

int
drm_gem_flink_ioctl(struct drm_device *dev, void *data,
                    struct drm_file *file_priv)
{
        struct drm_gem_flink *args = data;
        struct drm_gem_object *obj;
        int ret;

        if (!(dev->driver->driver_features & DRIVER_GEM))
                return -ENODEV;

        obj = drm_gem_object_lookup(dev, file_priv, args->handle);
        if (obj == NULL)
                return -ENOENT;

        ret = drm_gem_name_create(&dev->object_names, obj, &obj->name);
        if (ret != 0) {
                if (ret == -EALREADY)
                        ret = 0;
                drm_gem_object_unreference_unlocked(obj);
        }
        if (ret == 0)
                args->name = obj->name;
        return ret;
}

int
drm_gem_open_ioctl(struct drm_device *dev, void *data,
                   struct drm_file *file_priv)
{
        struct drm_gem_open *args = data;
        struct drm_gem_object *obj;
        int ret;
        u32 handle;

        if (!(dev->driver->driver_features & DRIVER_GEM))
                return -ENODEV;

        obj = drm_gem_name_ref(&dev->object_names, args->name,
            (void (*)(void *))drm_gem_object_reference);
        if (!obj)
                return -ENOENT;

        ret = drm_gem_handle_create(file_priv, obj, &handle);
        drm_gem_object_unreference_unlocked(obj);
        if (ret)
                return ret;

        args->handle = handle;
        args->size = obj->size;

        return 0;
}

void
drm_gem_open(struct drm_device *dev, struct drm_file *file_private)
{

        drm_gem_names_init(&file_private->object_names);
}

static int
drm_gem_object_release_handle(uint32_t name, void *ptr, void *data)
{
        struct drm_file *file_priv = data;
        struct drm_gem_object *obj = ptr;
        struct drm_device *dev = obj->dev;

#if defined(FREEBSD_NOTYET)
        drm_gem_remove_prime_handles(obj, file_priv);
#endif

        if (dev->driver->gem_close_object)
                dev->driver->gem_close_object(obj, file_priv);

        drm_gem_object_handle_unreference_unlocked(obj);

        return 0;
}

void
drm_gem_release(struct drm_device *dev, struct drm_file *file_private)
{
        drm_gem_names_foreach(&file_private->object_names,
            drm_gem_object_release_handle, file_private);

        drm_gem_names_fini(&file_private->object_names);
}

void
drm_gem_object_release(struct drm_gem_object *obj)
{

        /*
         * obj->vm_obj can be NULL for private gem objects.
         */
        vm_object_deallocate(obj->vm_obj);
}
EXPORT_SYMBOL(drm_gem_object_release);

void
drm_gem_object_free(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;

        DRM_LOCK_ASSERT(dev);
        if (dev->driver->gem_free_object != NULL)
                dev->driver->gem_free_object(obj);
}
EXPORT_SYMBOL(drm_gem_object_free);

void drm_gem_object_handle_free(struct drm_gem_object *obj)
{
        struct drm_device *dev = obj->dev;
        struct drm_gem_object *obj1;

        if (obj->name) {
                obj1 = drm_gem_names_remove(&dev->object_names, obj->name);
                obj->name = 0;
                drm_gem_object_unreference(obj1);
        }
}

static struct drm_gem_object *
drm_gem_object_from_offset(struct drm_device *dev, vm_ooffset_t offset)
{
        struct drm_gem_object *obj;
        struct drm_gem_mm *mm;
        struct drm_hash_item *map_list;

        if ((offset & DRM_GEM_MAPPING_MASK) != DRM_GEM_MAPPING_KEY)
                return (NULL);
        offset &= ~DRM_GEM_MAPPING_KEY;
        mm = dev->mm_private;
        if (drm_ht_find_item(&mm->offset_hash, DRM_GEM_MAPPING_IDX(offset),
            &map_list) != 0) {
        DRM_DEBUG("drm_gem_object_from_offset: offset 0x%jx obj not found\n",
                    (uintmax_t)offset);
                return (NULL);
        }
        obj = __containerof(map_list, struct drm_gem_object, map_list);
        return (obj);
}

int
drm_gem_mmap_single(struct drm_device *dev, vm_ooffset_t *offset, vm_size_t size,
    struct vm_object **obj_res, int nprot)
{
        struct drm_gem_object *gem_obj;
        struct vm_object *vm_obj;

        DRM_LOCK(dev);
        gem_obj = drm_gem_object_from_offset(dev, *offset);
        if (gem_obj == NULL) {
                DRM_UNLOCK(dev);
                return (-ENODEV);
        }
        drm_gem_object_reference(gem_obj);
        DRM_UNLOCK(dev);
        vm_obj = cdev_pager_allocate(gem_obj, OBJT_MGTDEVICE,
            dev->driver->gem_pager_ops, size, nprot,
            DRM_GEM_MAPPING_MAPOFF(*offset), curthread->td_ucred);
        if (vm_obj == NULL) {
                drm_gem_object_unreference_unlocked(gem_obj);
                return (-EINVAL);
        }
        *offset = DRM_GEM_MAPPING_MAPOFF(*offset);
        *obj_res = vm_obj;
        return (0);
}

void
drm_gem_pager_dtr(void *handle)
{
        struct drm_gem_object *obj;
        struct drm_device *dev;

        obj = handle;
        dev = obj->dev;

        DRM_LOCK(dev);
        drm_gem_free_mmap_offset(obj);
        drm_gem_object_unreference(obj);
        DRM_UNLOCK(dev);
}