Re: [PATCH v2 10/10] drm/ofdrm: Support color management

[Javier Martinez Canillas <javierm@redhat.com>]

On 7/20/22 16:27, Thomas Zimmermann wrote:
> Support the CRTC's color-management property and implement each model's
> palette support.
> 
> The OF hardware has different methods of setting the palette. The
> respective code has been taken from fbdev's offb and refactored into
> per-model device functions. The device functions integrate this
> functionality into the overall modesetting.
> 
> As palette handling is a CRTC property that depends on the primary
> plane's color format, the plane's atomic_check helper now updates the
> format field in ofdrm's custom CRTC state. The CRTC's atomic_flush
> helper updates the palette for the format as needed.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---

Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>

[...]

> +static void __iomem *ofdrm_mach64_cmap_ioremap(struct ofdrm_device *odev,
> +					       struct device_node *of_node,
> +					       u64 fb_base)
> +{
> +	struct drm_device *dev = &odev->dev;
> +	u64 address;
> +	void __iomem *cmap_base;
> +
> +	address = fb_base & 0xff000000ul;
> +	address += 0x7ff000;
> +

It would be good to know where these addresses are coming from. Maybe some
constant macros or a comment ? Same for the other places where addresses
and offsets are used.

[...]

>  static struct ofdrm_crtc_state *to_ofdrm_crtc_state(struct drm_crtc_state *base)
> @@ -376,10 +735,12 @@ static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>  						   struct drm_atomic_state *new_state)
>  {
>  	struct drm_plane_state *new_plane_state = drm_atomic_get_new_plane_state(new_state, plane);
> +	struct drm_framebuffer *new_fb = new_plane_state->fb;
>  	struct drm_crtc_state *new_crtc_state;
> +	struct ofdrm_crtc_state *new_ofdrm_crtc_state;
>  	int ret;
>  
> -	if (!new_plane_state->fb)
> +	if (!new_fb)
>  		return 0;
>  
>  	new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
> @@ -391,6 +752,14 @@ static int ofdrm_primary_plane_helper_atomic_check(struct drm_plane *plane,
>  	if (ret)
>  		return ret;
>  
> +	if (!new_plane_state->visible)
> +		return 0;
> +
> +	new_crtc_state = drm_atomic_get_new_crtc_state(new_state, new_plane_state->crtc);
> +
> +	new_ofdrm_crtc_state = to_ofdrm_crtc_state(new_crtc_state);
> +	new_ofdrm_crtc_state->format = new_fb->format;
> +

Ah, I understand now why you didn't factor out the .atomic_check callbacks
for the two drivers in a fwfb helper. Maybe you can also add a comment to
mention that this updates the format so the CRTC palette can be applied in
the .atomic_flush callback ?

-- 
Best regards,

Javier Martinez Canillas
Linux Engineering
Red Hat