On Tue, Aug 17, 2021 at 02:29:13PM +0200, Noralf Trønnes wrote:
> Add XRGB8888 emulation support for devices that can only do RGB888.
>
> Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
> Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/drm_format_helper.c | 38 +++++++++++++++++++++++++++++
> include/drm/drm_format_helper.h | 2 ++
> 2 files changed, 40 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
> index 53b426da7467..c42d50315123 100644
> --- a/drivers/gpu/drm/drm_format_helper.c
> +++ b/drivers/gpu/drm/drm_format_helper.c
> @@ -297,6 +297,44 @@ static void drm_fb_xrgb8888_to_rgb888_line(u8 *dbuf, u32 *sbuf,
> }
> }
>
> +/**
> + * drm_fb_xrgb8888_to_rgb888 - Convert XRGB8888 to RGB888 clip buffer
> + * @dst: RGB888 destination buffer
> + * @src: XRGB8888 source buffer
> + * @fb: DRM framebuffer
> + * @clip: Clip rectangle area to copy
> + *
> + * Drivers can use this function for RGB888 devices that don't natively
> + * support XRGB8888.
> + *
> + * This function does not apply clipping on dst, i.e. the destination
> + * is a small buffer containing the clip rect only.
> + */
> +void drm_fb_xrgb8888_to_rgb888(void *dst, void *src, struct drm_framebuffer *fb,
> + struct drm_rect *clip)
I do wonder whether we really need all the combinations here. E.g. if we
allow dst_pitch == 0 and just automatically pick this one here, and then
paper over the __iomem differences with dma_buf_map we wouldn't need two
different functions.
Just an idea.
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> +{
> + size_t width = drm_rect_width(clip);
> + size_t src_len = width * sizeof(u32);
> + unsigned int y;
> + void *sbuf;
> +
> + /* Use a buffer to speed up access on buffers with uncached read mapping (i.e. WC) */
> + sbuf = kmalloc(src_len, GFP_KERNEL);
> + if (!sbuf)
> + return;
> +
> + src += clip_offset(clip, fb->pitches[0], sizeof(u32));
> + for (y = 0; y < drm_rect_height(clip); y++) {
> + memcpy(sbuf, src, src_len);
> + drm_fb_xrgb8888_to_rgb888_line(dst, sbuf, width);
> + src += fb->pitches[0];
> + dst += width * 3;
> + }
> +
> + kfree(sbuf);
> +}
> +EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888);
> +
> /**
> * drm_fb_xrgb8888_to_rgb888_dstclip - Convert XRGB8888 to RGB888 clip buffer
> * @dst: RGB565 destination buffer (iomem)
> diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
> index d0809aff5cf8..e86925cf07b9 100644
> --- a/include/drm/drm_format_helper.h
> +++ b/include/drm/drm_format_helper.h
> @@ -24,6 +24,8 @@ void drm_fb_xrgb8888_to_rgb565(void *dst, void *vaddr,
> void drm_fb_xrgb8888_to_rgb565_dstclip(void __iomem *dst, unsigned int dst_pitch,
> void *vaddr, struct drm_framebuffer *fb,
> struct drm_rect *clip, bool swab);
> +void drm_fb_xrgb8888_to_rgb888(void *dst, void *src, struct drm_framebuffer *fb,
> + struct drm_rect *clip);
> void drm_fb_xrgb8888_to_rgb888_dstclip(void __iomem *dst, unsigned int dst_pitch,
> void *vaddr, struct drm_framebuffer *fb,
> struct drm_rect *clip);
> --
> 2.32.0
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
