dma-buf.h

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/*
 * Header file for dma buffer sharing framework.
 *
 * Copyright(C) 2011 Linaro Limited. All rights reserved.
 * Author: Sumit Semwal <[email protected]>
 *
 * Many thanks to linaro-mm-sig list, and specially
 * Arnd Bergmann <[email protected]>, Rob Clark <[email protected]> and
 * Daniel Vetter <[email protected]> for their support in creation and
 * refining of this idea.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __DMA_BUF_H__
#define __DMA_BUF_H__

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

struct device;
struct dma_buf;
struct dma_buf_attachment;

struct dma_buf_ops {
    int (*attach)(struct dma_buf *, struct device *,
            struct dma_buf_attachment *);

    void (*detach)(struct dma_buf *, struct dma_buf_attachment *);

    /* For {map,unmap}_dma_buf below, any specific buffer attributes
     * required should get added to device_dma_parameters accessible
     * via dev->dma_params.
     */
    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);
    /* TODO: Add try_map_dma_buf version, to return immed with -EBUSY
     * if the call would block.
     */

    /* after final dma_buf_put() */
    void (*release)(struct dma_buf *);

    int (*begin_cpu_access)(struct dma_buf *, size_t, size_t,
                enum dma_data_direction);
    void (*end_cpu_access)(struct dma_buf *, size_t, size_t,
                   enum dma_data_direction);
    void *(*kmap_atomic)(struct dma_buf *, unsigned long);
    void (*kunmap_atomic)(struct dma_buf *, unsigned long, void *);
    void *(*kmap)(struct dma_buf *, unsigned long);
    void (*kunmap)(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);
};

struct dma_buf {
    size_t size;
    struct file *file;
    struct list_head attachments;
    const struct dma_buf_ops *ops;
    /* mutex to serialize list manipulation and attach/detach */
    struct mutex lock;
    void *priv;
};

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

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

#ifdef CONFIG_DMA_SHARED_BUFFER
struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
                            struct device *dev);
void dma_buf_detach(struct dma_buf *dmabuf,
                struct dma_buf_attachment *dmabuf_attach);
struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
                   size_t size, int flags);
int dma_buf_fd(struct dma_buf *dmabuf, int flags);
struct dma_buf *dma_buf_get(int fd);
void dma_buf_put(struct dma_buf *dmabuf);

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);
int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
                 enum dma_data_direction dir);
void dma_buf_end_cpu_access(struct dma_buf *dma_buf, size_t start, size_t len,
                enum dma_data_direction dir);
void *dma_buf_kmap_atomic(struct dma_buf *, unsigned long);
void dma_buf_kunmap_atomic(struct dma_buf *, unsigned long, void *);
void *dma_buf_kmap(struct dma_buf *, unsigned long);
void dma_buf_kunmap(struct dma_buf *, unsigned long, void *);

int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *,
         unsigned long);
void *dma_buf_vmap(struct dma_buf *);
void dma_buf_vunmap(struct dma_buf *, void *vaddr);
#else

static inline struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
                            struct device *dev)
{
    return ERR_PTR(-ENODEV);
}

static inline void dma_buf_detach(struct dma_buf *dmabuf,
                  struct dma_buf_attachment *dmabuf_attach)
{
    return;
}

static inline struct dma_buf *dma_buf_export(void *priv,
                         const struct dma_buf_ops *ops,
                         size_t size, int flags)
{
    return ERR_PTR(-ENODEV);
}

static inline int dma_buf_fd(struct dma_buf *dmabuf, int flags)
{
    return -ENODEV;
}

static inline struct dma_buf *dma_buf_get(int fd)
{
    return ERR_PTR(-ENODEV);
}

static inline void dma_buf_put(struct dma_buf *dmabuf)
{
    return;
}

static inline struct sg_table *dma_buf_map_attachment(
    struct dma_buf_attachment *attach, enum dma_data_direction write)
{
    return ERR_PTR(-ENODEV);
}

static inline void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
            struct sg_table *sg, enum dma_data_direction dir)
{
    return;
}

static inline int dma_buf_begin_cpu_access(struct dma_buf *dmabuf,
                       size_t start, size_t len,
                       enum dma_data_direction dir)
{
    return -ENODEV;
}

static inline void dma_buf_end_cpu_access(struct dma_buf *dmabuf,
                      size_t start, size_t len,
                      enum dma_data_direction dir)
{
}

static inline void *dma_buf_kmap_atomic(struct dma_buf *dmabuf,
                    unsigned long pnum)
{
    return NULL;
}

static inline void dma_buf_kunmap_atomic(struct dma_buf *dmabuf,
                     unsigned long pnum, void *vaddr)
{
}

static inline void *dma_buf_kmap(struct dma_buf *dmabuf, unsigned long pnum)
{
    return NULL;
}

static inline void dma_buf_kunmap(struct dma_buf *dmabuf,
                  unsigned long pnum, void *vaddr)
{
}

static inline int dma_buf_mmap(struct dma_buf *dmabuf,
                   struct vm_area_struct *vma,
                   unsigned long pgoff)
{
    return -ENODEV;
}

static inline void *dma_buf_vmap(struct dma_buf *dmabuf)
{
    return NULL;
}

static inline void dma_buf_vunmap(struct dma_buf *dmabuf, void *vaddr)
{
}
#endif /* CONFIG_DMA_SHARED_BUFFER */

#endif /* __DMA_BUF_H__ */