linux/drivers/media/common/videobuf2/videobuf2-memops.c

/*
 * videobuf2-memops.c - generic memory handling routines for videobuf2
 *
 * Copyright (C) 2010 Samsung Electronics
 *
 * Author: Pawel Osciak <[email protected]>
 *	   Marek Szyprowski <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation.
 */

#include <linux/slab.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/file.h>

#include <media/videobuf2-v4l2.h>
#include <media/videobuf2-memops.h>

/**
 * vb2_create_framevec() - map virtual addresses to pfns
 * @start:	Virtual user address where we start mapping
 * @length:	Length of a range to map
 * @write:	Should we map for writing into the area
 *
 * This function allocates and fills in a vector with pfns corresponding to
 * virtual address range passed in arguments. If pfns have corresponding pages,
 * page references are also grabbed to pin pages in memory. The function
 * returns pointer to the vector on success and error pointer in case of
 * failure. Returned vector needs to be freed via vb2_destroy_pfnvec().
 */
struct frame_vector *vb2_create_framevec(unsigned long start,
					 unsigned long length,
					 bool write)
{ … }
EXPORT_SYMBOL(…);

/**
 * vb2_destroy_framevec() - release vector of mapped pfns
 * @vec:	vector of pfns / pages to release
 *
 * This releases references to all pages in the vector @vec (if corresponding
 * pfns are backed by pages) and frees the passed vector.
 */
void vb2_destroy_framevec(struct frame_vector *vec)
{ … }
EXPORT_SYMBOL(…);

/**
 * vb2_common_vm_open() - increase refcount of the vma
 * @vma:	virtual memory region for the mapping
 *
 * This function adds another user to the provided vma. It expects
 * struct vb2_vmarea_handler pointer in vma->vm_private_data.
 */
static void vb2_common_vm_open(struct vm_area_struct *vma)
{ … }

/**
 * vb2_common_vm_close() - decrease refcount of the vma
 * @vma:	virtual memory region for the mapping
 *
 * This function releases the user from the provided vma. It expects
 * struct vb2_vmarea_handler pointer in vma->vm_private_data.
 */
static void vb2_common_vm_close(struct vm_area_struct *vma)
{ … }

/*
 * vb2_common_vm_ops - common vm_ops used for tracking refcount of mmapped
 * video buffers
 */
const struct vm_operations_struct vb2_common_vm_ops = …;
EXPORT_SYMBOL_GPL(…);

MODULE_DESCRIPTION(…) …;
MODULE_AUTHOR(…) …;
MODULE_LICENSE(…) …;