/*
 * Copyright (c) 2018-2020 François Tigeot <ftigeot@wolfpond.org>
 * All rights reserved.
 *
 * 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 unmodified, 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 ``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 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.
 */

#ifndef LINUX_DMA_BUF_H
#define LINUX_DMA_BUF_H

#include <linux/err.h>
#include <linux/scatterlist.h>
#include <linux/list.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
#include <linux/dma-fence.h>
#include <linux/wait.h>

#include <linux/slab.h>

struct dma_buf;
struct dma_buf_attachment;

struct dma_buf_ops {
        struct sg_table * (*map_dma_buf)(struct dma_buf_attachment *,
                                                enum dma_data_direction);
        void (*unmap_dma_buf)(struct dma_buf_attachment *,
                                                struct sg_table *,
                                                enum dma_data_direction);
        void (*release)(struct dma_buf *);
        void *(*map)(struct dma_buf *, unsigned long);
        void *(*map_atomic)(struct dma_buf *, unsigned long);
        void (*unmap)(struct dma_buf *, unsigned long, void *);
        void (*unmap_atomic)(struct dma_buf *, unsigned long, void *);
        int (*mmap)(struct dma_buf *, struct vm_area_struct *vma);
        void *(*vmap)(struct dma_buf *);
        void (*vunmap)(struct dma_buf *, void *vaddr);
        int (*begin_cpu_access)(struct dma_buf *, enum dma_data_direction);
        int (*end_cpu_access)(struct dma_buf *, enum dma_data_direction);
        int (*attach)(struct dma_buf *, struct dma_buf_attachment *);
        void (*detach)(struct dma_buf *, struct dma_buf_attachment *);
};

struct dma_buf {
        struct reservation_object *resv;
        void *priv;
        const struct dma_buf_ops *ops;
        size_t size;
        struct file *file;
};

struct dma_buf_attachment {
        struct dma_buf *dmabuf;
        struct device *dev;
        void *priv;
};

struct dma_buf_export_info {
        const struct dma_buf_ops *ops;
        size_t size;
        int flags;
        void *priv;
        struct reservation_object *resv;
};

struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info);

#define DEFINE_DMA_BUF_EXPORT_INFO(name)        \
        struct dma_buf_export_info name = {     \
        }

struct sg_table * dma_buf_map_attachment(struct dma_buf_attachment *,
                                                enum dma_data_direction);
void dma_buf_unmap_attachment(struct dma_buf_attachment *,
                                struct sg_table *, enum dma_data_direction);

static inline struct dma_buf_attachment *
dma_buf_attach(struct dma_buf *dmabuf, struct device *dev)
{
        STUB();
        return NULL;
}

static inline void
get_dma_buf(struct dma_buf *dmabuf)
{
        fhold(dmabuf->file);
}

static inline void
dma_buf_put(struct dma_buf *dmabuf)
{
        //kprintf("dma_buf_put: dmabuf=%p, dmabuf->file=%p\n", dmabuf, dmabuf ? dmabuf->file : NULL);
        if (dmabuf == NULL)
                return;

        if (dmabuf->file == NULL)
                return;
        fdrop(dmabuf->file);
}

int dma_buf_fd(struct dma_buf *dmabuf, int flags);

struct dma_buf *dma_buf_get(int fd);

static inline void
dma_buf_detach(struct dma_buf *dmabuf,
               struct dma_buf_attachment *dmabuf_attach)
{
        panic("dma_buf_attach is not implemented");
}

#endif /* LINUX_DMA_BUF_H */