Re: [PATCH 2/2] [media] videobuf-dma-contig: use vm_iomap_memory()

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em Wed, 17 Apr 2013 09:22:16 -0300
Mauro Carvalho Chehab <mchehab@redhat.com> escreveu:

> vm_iomap_memory() provides a better end user interface than
> remap_pfn_range(), as it does the needed tests before doing
> mmap.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
> ---
>  drivers/media/v4l2-core/videobuf-dma-contig.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
> 
> diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c
> index 67f572c..7e6b209 100644
> --- a/drivers/media/v4l2-core/videobuf-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf-dma-contig.c
> @@ -303,14 +303,9 @@ static int __videobuf_mmap_mapper(struct videobuf_queue *q,
>  		goto error;
>  
>  	/* Try to remap memory */
> -
>  	size = vma->vm_end - vma->vm_start;
> -	size = (size < mem->size) ? size : mem->size;
> -
>  	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
> -	retval = remap_pfn_range(vma, vma->vm_start,
> -				 mem->dma_handle >> PAGE_SHIFT,
> -				 size, vma->vm_page_prot);
> +	retval = vm_iomap_memory(vma, vma->vm_start, size);

Just to be sure, that changing from remap_pfn_range() to io_remap_pfn_range()
won't cause any side-effects, I double-checked that, for all drivers using
this code, that remap_pfn_range is equal to io_remap_pfn_range.

The Timberdale driver was a little trickier to check, as VIDEO_TIMBERDALE
doesn't depend on any architecture. However, this driver was submitted and
was known to work only on the Intel in-Vehicle Infotainment reference board
russelville. According with http://wiki.meego.com/In-vehicle, the
architecture for it is x86 (Intel Atom Z5xx).

In summary, those are the archs where this core driver is used, with the
corresponding drivers that make such usage:

powerpc:
	drivers/media/platform/fsl-viu.c

arm:
	drivers/media/platform/omap/omap_vout.c
	drivers/media/platform/omap/omap_vout_vrfb.c
	drivers/media/platform/soc_camera/mx1_camera.c
	drivers/media/platform/soc_camera/omap1_camera.c

sh:
	drivers/media/platform/sh_vou.c

x86:
	drivers/media/platform/timblogiw.c

-- 

Cheers,
Mauro