Re: [PATCH 1/9] drm/format-helper: Export drm_fb_clip_offset()

[Sam Ravnborg <sam@ravnborg.org>]

Hi Thomas,

On Fri, Oct 22, 2021 at 03:28:21PM +0200, Thomas Zimmermann wrote:
> Provide a function that computes the offset into a blit destination
> buffer. This will allow to move destination-buffer clipping into the
> format-helper callers.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/drm_format_helper.c | 10 ++++++++--
>  include/drm/drm_format_helper.h     |  4 ++++
>  2 files changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
> index 69fde60e36b3..28e9d0d89270 100644
> --- a/drivers/gpu/drm/drm_format_helper.c
> +++ b/drivers/gpu/drm/drm_format_helper.c
> @@ -17,12 +17,18 @@
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_rect.h>
>  
> -static unsigned int clip_offset(struct drm_rect *clip,
> -				unsigned int pitch, unsigned int cpp)
> +static unsigned int clip_offset(const struct drm_rect *clip, unsigned int pitch, unsigned int cpp)
>  {
>  	return clip->y1 * pitch + clip->x1 * cpp;
>  }
>  
> +unsigned long drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info *format,
> +				 const struct drm_rect *clip)
> +{
> +	return clip_offset(clip, pitch, format->cpp[0]);
> +}
> +EXPORT_SYMBOL(drm_fb_clip_offset);

Exported functions are expected to have kernel-doc documentation.
Just copy more or less from the changelog I think.

Anywhere else (I looked in struct drm_framebuffer) we only need unsigned
int for offsets and width/length - so I cannot see why we do an unsigned
int => unsigned long conversion here.

	Sam

> +
>  /**
>   * drm_fb_memcpy - Copy clip buffer
>   * @dst: Destination buffer
> diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
> index e86925cf07b9..90b9bd9ecb83 100644
> --- a/include/drm/drm_format_helper.h
> +++ b/include/drm/drm_format_helper.h
> @@ -6,9 +6,13 @@
>  #ifndef __LINUX_DRM_FORMAT_HELPER_H
>  #define __LINUX_DRM_FORMAT_HELPER_H
>  
> +struct drm_format_info;
>  struct drm_framebuffer;
>  struct drm_rect;
>  
> +unsigned long drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info *format,
> +				 const struct drm_rect *clip);
> +
>  void drm_fb_memcpy(void *dst, void *vaddr, struct drm_framebuffer *fb,
>  		   struct drm_rect *clip);
>  void drm_fb_memcpy_dstclip(void __iomem *dst, unsigned int dst_pitch, void *vaddr,
> -- 
> 2.33.0
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