Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 21fb0cb7 authored by Jan Kara's avatar Jan Kara Committed by Mauro Carvalho Chehab
Browse files

[media] vb2: Provide helpers for mapping virtual addresses 



Provide simple helper functions to map virtual address range into an
array of pfns / pages.

Tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@osg.samsung.com>
parent 8a677b6e

drivers/media/v4l2-core/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ config VIDEOBUF2_CORE 


config VIDEOBUF2_MEMOPS

	tristate

	select FRAME_VECTOR



config VIDEOBUF2_DMA_CONTIG

	tristate

drivers/media/v4l2-core/videobuf2-memops.c

+58 −0
Original line number Diff line number Diff line
@@ -136,6 +136,64 @@ int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size, 
}

EXPORT_SYMBOL_GPL(vb2_get_contig_userptr);



/**

 * 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)

{

	int ret;

	unsigned long first, last;

	unsigned long nr;

	struct frame_vector *vec;



	first = start >> PAGE_SHIFT;

	last = (start + length - 1) >> PAGE_SHIFT;

	nr = last - first + 1;

	vec = frame_vector_create(nr);

	if (!vec)

		return ERR_PTR(-ENOMEM);

	ret = get_vaddr_frames(start, nr, write, 1, vec);

	if (ret < 0)

		goto out_destroy;

	/* We accept only complete set of PFNs */

	if (ret != nr) {

		ret = -EFAULT;

		goto out_release;

	}

	return vec;

out_release:

	put_vaddr_frames(vec);

out_destroy:

	frame_vector_destroy(vec);

	return ERR_PTR(ret);

}

EXPORT_SYMBOL(vb2_create_framevec);



/**

 * 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)

{

	put_vaddr_frames(vec);

	frame_vector_destroy(vec);

}

EXPORT_SYMBOL(vb2_destroy_framevec);



/**

 * vb2_common_vm_open() - increase refcount of the vma

 * @vma:	virtual memory region for the mapping

include/media/videobuf2-memops.h

+5 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#define _MEDIA_VIDEOBUF2_MEMOPS_H



#include <media/videobuf2-core.h>

#include <linux/mm.h>



/**

 * vb2_vmarea_handler - common vma refcount tracking handler
@@ -36,5 +37,9 @@ int vb2_get_contig_userptr(unsigned long vaddr, unsigned long size, 
struct vm_area_struct *vb2_get_vma(struct vm_area_struct *vma);

void vb2_put_vma(struct vm_area_struct *vma);



struct frame_vector *vb2_create_framevec(unsigned long start,

					 unsigned long length,

					 bool write);

void vb2_destroy_framevec(struct frame_vector *vec);



#endif