Re: [PATCH 03/12] drm/format-helper: Convert drm_fb_swab() to struct iosys_map

[Sam Ravnborg <sam@ravnborg.org>]

Hi Thomas,

On Wed, Jul 27, 2022 at 01:33:03PM +0200, Thomas Zimmermann wrote:
> Convert drm_fb_swab() to use struct iosys_map() and convert users. The
> new interface supports multi-plane color formats.
It swabs only plane[0], sbut this is maybe enough to say so.

A few comments in the following.

	Sam

> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/drm_format_helper.c | 38 +++++++++++++++++++++--------
>  drivers/gpu/drm/drm_mipi_dbi.c      |  2 +-
>  drivers/gpu/drm/gud/gud_pipe.c      |  2 +-
>  include/drm/drm_format_helper.h     |  6 ++---
>  4 files changed, 33 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
> index 49589b442f18..fa22d3cb11e8 100644
> --- a/drivers/gpu/drm/drm_format_helper.c
> +++ b/drivers/gpu/drm/drm_format_helper.c
> @@ -196,9 +196,9 @@ static void drm_fb_swab32_line(void *dbuf, const void *sbuf, unsigned int pixels
>  
>  /**
>   * drm_fb_swab - Swap bytes into clip buffer
> - * @dst: Destination buffer
> - * @dst_pitch: Number of bytes between two consecutive scanlines within dst
> - * @src: Source buffer
> + * @dst: Array of destination buffers
> + * @dst_pitch: Array of numbers of bytes between two consecutive scanlines within dst
Document that it may be NULL?

> + * @vmap: Array of source buffers
Prefer that the source is named src, and vmap smells like system
(virtual) memory to me.
Also vmap must be system memory - but this is maybe fixed later.


>   * @fb: DRM framebuffer
>   * @clip: Clip rectangle area to copy
>   * @cached: Source buffer is mapped cached (eg. not write-combined)
> @@ -209,24 +209,42 @@ static void drm_fb_swab32_line(void *dbuf, const void *sbuf, unsigned int pixels
>   * This function does not apply clipping on dst, i.e. the destination
>   * is at the top-left corner.
>   */
> -void drm_fb_swab(void *dst, unsigned int dst_pitch, const void *src,
> -		 const struct drm_framebuffer *fb, const struct drm_rect *clip,
> -		 bool cached)
> +void drm_fb_swab(struct iosys_map *dst, const unsigned int *dst_pitch,
> +		 const struct iosys_map *vmap, const struct drm_framebuffer *fb,
> +		 const struct drm_rect *clip, bool cached)
>  {
> -	u8 cpp = fb->format->cpp[0];
> +	static const unsigned int default_dst_pitch[DRM_FORMAT_MAX_PLANES] = {
> +		0, 0, 0, 0
> +	};
> +	const struct drm_format_info *format = fb->format;
> +	u8 cpp = format->cpp[0];
	u8 cpp = drm_format_info_bpp(format, 0) / 8;

> +	void (*swab_line)(void *dbuf, const void *sbuf, unsigned int npixels);
>  
>  	switch (cpp) {
>  	case 4:
> -		drm_fb_xfrm(dst, dst_pitch, cpp, src, fb, clip, cached, drm_fb_swab32_line);
> +		swab_line = drm_fb_swab32_line;
>  		break;
>  	case 2:
> -		drm_fb_xfrm(dst, dst_pitch, cpp, src, fb, clip, cached, drm_fb_swab16_line);
> +		swab_line = drm_fb_swab16_line;
>  		break;
>  	default:
>  		drm_warn_once(fb->dev, "Format %p4cc has unsupported pixel size.\n",
> -			      &fb->format->format);
> +			      &format->format);
> +		swab_line = NULL;
>  		break;
>  	}
> +	if (!swab_line)
> +		return;
> +
> +	if (!dst_pitch)
> +		dst_pitch = default_dst_pitch;
> +
> +	if (dst->is_iomem)
> +		drm_fb_xfrm_toio(dst[0].vaddr_iomem, dst_pitch[0], cpp,
> +				 vmap[0].vaddr, fb, clip, cached, swab_line);
> +	else
> +		drm_fb_xfrm(dst[0].vaddr, dst_pitch[0], cpp, vmap[0].vaddr, fb,
> +			    clip, cached, swab_line);
Here vmap is assumes system memory, not IO. I assume this is fixed
later.

>  }
>  EXPORT_SYMBOL(drm_fb_swab);
>  
> diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
> index 22451806fb5c..973a75585cad 100644
> --- a/drivers/gpu/drm/drm_mipi_dbi.c
> +++ b/drivers/gpu/drm/drm_mipi_dbi.c
> @@ -221,7 +221,7 @@ int mipi_dbi_buf_copy(void *dst, struct drm_framebuffer *fb,
>  	switch (fb->format->format) {
>  	case DRM_FORMAT_RGB565:
>  		if (swap)
> -			drm_fb_swab(dst, 0, src, fb, clip, !gem->import_attach);
> +			drm_fb_swab(&dst_map, NULL, data, fb, clip, !gem->import_attach);
>  		else
>  			drm_fb_memcpy(&dst_map, NULL, data, fb, clip);
>  		break;
> diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c
> index 449c95a4aee0..a15cda9ba058 100644
> --- a/drivers/gpu/drm/gud/gud_pipe.c
> +++ b/drivers/gpu/drm/gud/gud_pipe.c
> @@ -205,7 +205,7 @@ static int gud_prep_flush(struct gud_device *gdrm, struct drm_framebuffer *fb,
>  			len = gud_xrgb8888_to_color(buf, format, vaddr, fb, rect);
>  		}
>  	} else if (gud_is_big_endian() && format->cpp[0] > 1) {
> -		drm_fb_swab(buf, 0, vaddr, fb, rect, !import_attach);
> +		drm_fb_swab(&dst, NULL, map_data, fb, rect, !import_attach);
>  	} else if (compression && !import_attach && pitch == fb->pitches[0]) {
>  		/* can compress directly from the framebuffer */
>  		buf = vaddr + rect->y1 * pitch;
> diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
> index 8af6a2717bc9..60944feaa936 100644
> --- a/include/drm/drm_format_helper.h
> +++ b/include/drm/drm_format_helper.h
> @@ -17,9 +17,9 @@ unsigned int drm_fb_clip_offset(unsigned int pitch, const struct drm_format_info
>  void drm_fb_memcpy(struct iosys_map *dst, const unsigned int *dst_pitch,
>  		   const struct iosys_map *vmap, const struct drm_framebuffer *fb,
>  		   const struct drm_rect *clip);
> -void drm_fb_swab(void *dst, unsigned int dst_pitch, const void *src,
> -		 const struct drm_framebuffer *fb, const struct drm_rect *clip,
> -		 bool cached);
> +void drm_fb_swab(struct iosys_map *dst, const unsigned int *dst_pitch,
> +		 const struct iosys_map *vmap, const struct drm_framebuffer *fb,
> +		 const struct drm_rect *clip, bool cached);
>  void drm_fb_xrgb8888_to_rgb332(void *dst, unsigned int dst_pitch, const void *vaddr,
>  			       const struct drm_framebuffer *fb, const struct drm_rect *clip);
>  void drm_fb_xrgb8888_to_rgb565(void *dst, unsigned int dst_pitch, const void *vaddr,
> -- 
> 2.37.1