Re: [PATCH 2/3] drm/format-helper: Add drm_fb_xrgb8888_to_xrgb2101010_dstclip()

[Thomas Zimmermann <tzimmermann@suse.de>]

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Hi

Am 17.11.21 um 15:58 schrieb Hector Martin:
> Add XRGB8888 emulation support for devices that can only do XRGB2101010.
> 
> This is chiefly useful for simpledrm on Apple devices where the
> bootloader-provided framebuffer is 10-bit, which already works fine with
> simplefb. This is required to make simpledrm support this too.

As mentioned in the other review, this requires a rebase onto the latest 
DRM tree; preferably drm-tip.

Best regards
Thomas

> 
> Signed-off-by: Hector Martin <marcan@marcan.st>
> ---
>   drivers/gpu/drm/drm_format_helper.c | 64 +++++++++++++++++++++++++++++
>   include/drm/drm_format_helper.h     |  4 ++
>   2 files changed, 68 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
> index 69fde60e36b3..5998e57d6ff2 100644
> --- a/drivers/gpu/drm/drm_format_helper.c
> +++ b/drivers/gpu/drm/drm_format_helper.c
> @@ -378,6 +378,60 @@ void drm_fb_xrgb8888_to_rgb888_dstclip(void __iomem *dst, unsigned int dst_pitch
>   }
>   EXPORT_SYMBOL(drm_fb_xrgb8888_to_rgb888_dstclip);
>   
> +static void drm_fb_xrgb8888_to_xrgb2101010_line(u32 *dbuf, u32 *sbuf,
> +						unsigned int pixels)
> +{
> +	unsigned int x;
> +
> +	for (x = 0; x < pixels; x++) {
> +		*dbuf++ = ((sbuf[x] & 0x000000FF) << 2) |
> +			  ((sbuf[x] & 0x0000FF00) << 4) |
> +			  ((sbuf[x] & 0x00FF0000) << 6);
> +	}
> +}
> +
> +/**
> + * drm_fb_xrgb8888_to_xrgb2101010_dstclip - Convert XRGB8888 to XRGB2101010 clip
> + * buffer
> + * @dst: XRGB2101010 destination buffer (iomem)
> + * @dst_pitch: destination buffer pitch
> + * @vaddr: XRGB8888 source buffer
> + * @fb: DRM framebuffer
> + * @clip: Clip rectangle area to copy
> + *
> + * Drivers can use this function for XRGB2101010 devices that don't natively
> + * support XRGB8888.
> + *
> + * This function applies clipping on dst, i.e. the destination is a
> + * full (iomem) framebuffer but only the clip rect content is copied over.
> + */
> +void drm_fb_xrgb8888_to_xrgb2101010_dstclip(void __iomem *dst,
> +					    unsigned int dst_pitch, void *vaddr,
> +					    struct drm_framebuffer *fb,
> +					    struct drm_rect *clip)
> +{
> +	size_t linepixels = clip->x2 - clip->x1;
> +	size_t dst_len = linepixels * 4;
> +	unsigned int y, lines = clip->y2 - clip->y1;
> +	void *dbuf;
> +
> +	dbuf = kmalloc(dst_len, GFP_KERNEL);
> +	if (!dbuf)
> +		return;
> +
> +	vaddr += clip_offset(clip, fb->pitches[0], sizeof(u32));
> +	dst += clip_offset(clip, dst_pitch, sizeof(u32));
> +	for (y = 0; y < lines; y++) {
> +		drm_fb_xrgb8888_to_xrgb2101010_line(dbuf, vaddr, linepixels);
> +		memcpy_toio(dst, dbuf, dst_len);
> +		vaddr += fb->pitches[0];
> +		dst += dst_pitch;
> +	}
> +
> +	kfree(dbuf);
> +}
> +EXPORT_SYMBOL(drm_fb_xrgb8888_to_xrgb2101010_dstclip);
> +
>   /**
>    * drm_fb_xrgb8888_to_gray8 - Convert XRGB8888 to grayscale
>    * @dst: 8-bit grayscale destination buffer
> @@ -464,6 +518,10 @@ int drm_fb_blit_rect_dstclip(void __iomem *dst, unsigned int dst_pitch,
>   		fb_format = DRM_FORMAT_XRGB8888;
>   	if (dst_format == DRM_FORMAT_ARGB8888)
>   		dst_format = DRM_FORMAT_XRGB8888;
> +	if (fb_format == DRM_FORMAT_ARGB2101010)
> +		fb_format = DRM_FORMAT_XRGB2101010;
> +	if (dst_format == DRM_FORMAT_ARGB2101010)
> +		dst_format = DRM_FORMAT_XRGB2101010;
>   
>   	if (dst_format == fb_format) {
>   		drm_fb_memcpy_dstclip(dst, dst_pitch, vmap, fb, clip);
> @@ -482,6 +540,12 @@ int drm_fb_blit_rect_dstclip(void __iomem *dst, unsigned int dst_pitch,
>   							  vmap, fb, clip);
>   			return 0;
>   		}
> +	} else if (dst_format == DRM_FORMAT_XRGB2101010) {
> +		if (fb_format == DRM_FORMAT_XRGB8888) {
> +			drm_fb_xrgb8888_to_xrgb2101010_dstclip(dst, dst_pitch,
> +							       vmap, fb, clip);
> +			return 0;
> +		}
>   	}
>   
>   	return -EINVAL;
> diff --git a/include/drm/drm_format_helper.h b/include/drm/drm_format_helper.h
> index e86925cf07b9..a0faa710878b 100644
> --- a/include/drm/drm_format_helper.h
> +++ b/include/drm/drm_format_helper.h
> @@ -29,6 +29,10 @@ void drm_fb_xrgb8888_to_rgb888(void *dst, void *src, struct drm_framebuffer *fb,
>   void drm_fb_xrgb8888_to_rgb888_dstclip(void __iomem *dst, unsigned int dst_pitch,
>   				       void *vaddr, struct drm_framebuffer *fb,
>   				       struct drm_rect *clip);
> +void drm_fb_xrgb8888_to_xrgb2101010_dstclip(void __iomem *dst,
> +					    unsigned int dst_pitch, void *vaddr,
> +					    struct drm_framebuffer *fb,
> +					    struct drm_rect *clip);
>   void drm_fb_xrgb8888_to_gray8(u8 *dst, void *vaddr, struct drm_framebuffer *fb,
>   			      struct drm_rect *clip);
>   
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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