225 lines
8.4 KiB
C
225 lines
8.4 KiB
C
/*
|
|
* Header file for dma buffer sharing framework.
|
|
*
|
|
* Copyright(C) 2011 Linaro Limited. All rights reserved.
|
|
* Author: Sumit Semwal <sumit.semwal@ti.com>
|
|
*
|
|
* Many thanks to linaro-mm-sig list, and specially
|
|
* Arnd Bergmann <arnd@arndb.de>, Rob Clark <rob@ti.com> and
|
|
* Daniel Vetter <daniel@ffwll.ch> 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>
|
|
#include <linux/fence.h>
|
|
#include <linux/wait.h>
|
|
|
|
struct device;
|
|
struct dma_buf;
|
|
struct dma_buf_attachment;
|
|
|
|
/**
|
|
* struct dma_buf_ops - operations possible on struct dma_buf
|
|
* @attach: [optional] allows different devices to 'attach' themselves to the
|
|
* given buffer. It might return -EBUSY to signal that backing storage
|
|
* is already allocated and incompatible with the requirements
|
|
* of requesting device.
|
|
* @detach: [optional] detach a given device from this buffer.
|
|
* @map_dma_buf: returns list of scatter pages allocated, increases usecount
|
|
* of the buffer. Requires atleast one attach to be called
|
|
* before. Returned sg list should already be mapped into
|
|
* _device_ address space. This call may sleep. May also return
|
|
* -EINTR. Should return -EINVAL if attach hasn't been called yet.
|
|
* @unmap_dma_buf: decreases usecount of buffer, might deallocate scatter
|
|
* pages.
|
|
* @release: release this buffer; to be called after the last dma_buf_put.
|
|
* @begin_cpu_access: [optional] called before cpu access to invalidate cpu
|
|
* caches and allocate backing storage (if not yet done)
|
|
* respectively pin the object into memory.
|
|
* @end_cpu_access: [optional] called after cpu access to flush caches.
|
|
* @kmap_atomic: maps a page from the buffer into kernel address
|
|
* space, users may not block until the subsequent unmap call.
|
|
* This callback must not sleep.
|
|
* @kunmap_atomic: [optional] unmaps a atomically mapped page from the buffer.
|
|
* This Callback must not sleep.
|
|
* @kmap: maps a page from the buffer into kernel address space.
|
|
* @kunmap: [optional] unmaps a page from the buffer.
|
|
* @mmap: used to expose the backing storage to userspace. Note that the
|
|
* mapping needs to be coherent - if the exporter doesn't directly
|
|
* support this, it needs to fake coherency by shooting down any ptes
|
|
* when transitioning away from the cpu domain.
|
|
* @vmap: [optional] creates a virtual mapping for the buffer into kernel
|
|
* address space. Same restrictions as for vmap and friends apply.
|
|
* @vunmap: [optional] unmaps a vmap from the buffer
|
|
*/
|
|
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 *, enum dma_data_direction);
|
|
int (*end_cpu_access)(struct dma_buf *, 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 - shared buffer object
|
|
* @size: size of the buffer
|
|
* @file: file pointer used for sharing buffers across, and for refcounting.
|
|
* @attachments: list of dma_buf_attachment that denotes all devices attached.
|
|
* @ops: dma_buf_ops associated with this buffer object.
|
|
* @exp_name: name of the exporter; useful for debugging.
|
|
* @owner: pointer to exporter module; used for refcounting when exporter is a
|
|
* kernel module.
|
|
* @list_node: node for dma_buf accounting and debugging.
|
|
* @priv: exporter specific private data for this buffer object.
|
|
* @resv: reservation object linked to this dma-buf
|
|
*/
|
|
struct dma_buf {
|
|
size_t size;
|
|
struct file *file;
|
|
struct list_head attachments;
|
|
const struct dma_buf_ops *ops;
|
|
/* mutex to serialize list manipulation, attach/detach and vmap/unmap */
|
|
struct mutex lock;
|
|
unsigned vmapping_counter;
|
|
void *vmap_ptr;
|
|
const char *exp_name;
|
|
struct list_head list_node;
|
|
void *priv;
|
|
};
|
|
|
|
/**
|
|
* struct dma_buf_attachment - holds device-buffer attachment data
|
|
* @dmabuf: buffer for this attachment.
|
|
* @dev: device attached to the buffer.
|
|
* @node: list of dma_buf_attachment.
|
|
* @priv: exporter specific attachment data.
|
|
*
|
|
* This structure holds the attachment information between the dma_buf buffer
|
|
* and its user device(s). The list contains one attachment struct per device
|
|
* attached to the buffer.
|
|
*/
|
|
struct dma_buf_attachment {
|
|
struct dma_buf *dmabuf;
|
|
struct device *dev;
|
|
struct list_head node;
|
|
void *priv;
|
|
};
|
|
|
|
/**
|
|
* struct dma_buf_export_info - holds information needed to export a dma_buf
|
|
* @exp_name: name of the exporter - useful for debugging.
|
|
* @owner: pointer to exporter module - used for refcounting kernel module
|
|
* @ops: Attach allocator-defined dma buf ops to the new buffer
|
|
* @size: Size of the buffer
|
|
* @flags: mode flags for the file
|
|
* @resv: reservation-object, NULL to allocate default one
|
|
* @priv: Attach private data of allocator to this buffer
|
|
*
|
|
* This structure holds the information required to export the buffer. Used
|
|
* with dma_buf_export() only.
|
|
*/
|
|
struct dma_buf_export_info {
|
|
const char *exp_name;
|
|
struct module *owner;
|
|
const struct dma_buf_ops *ops;
|
|
size_t size;
|
|
int flags;
|
|
struct reservation_object *resv;
|
|
void *priv;
|
|
};
|
|
|
|
/**
|
|
* helper macro for exporters; zeros and fills in most common values
|
|
*/
|
|
#define DEFINE_DMA_BUF_EXPORT_INFO(a) \
|
|
struct dma_buf_export_info a = { .exp_name = KBUILD_MODNAME, \
|
|
.owner = THIS_MODULE }
|
|
|
|
/**
|
|
* get_dma_buf - convenience wrapper for get_file.
|
|
* @dmabuf: [in] pointer to dma_buf
|
|
*
|
|
* Increments the reference count on the dma-buf, needed in case of drivers
|
|
* that either need to create additional references to the dmabuf on the
|
|
* kernel side. For example, an exporter that needs to keep a dmabuf ptr
|
|
* so that subsequent exports don't create a new dmabuf.
|
|
*/
|
|
|
|
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(const struct dma_buf_export_info *exp_info);
|
|
|
|
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,
|
|
enum dma_data_direction dir);
|
|
int dma_buf_end_cpu_access(struct dma_buf *dma_buf,
|
|
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);
|
|
int dma_buf_debugfs_create_file(const char *name,
|
|
int (*write)(struct seq_file *));
|
|
#endif /* __DMA_BUF_H__ */
|