[PATCH 13/18] drm/vc4: hdmi: Define colorspace matrices

[Thomas Zimmermann]

Am 17.03.21 um 16:43 schrieb Maxime Ripard:
> The current CSC setup code for the BCM2711 uses a sequence of register
> writes to configure the CSC depending on whether we output using a full
> or limited range.
> 
> However, with the upcoming introduction of the YUV output, we're going
> to add new matrices to perform the conversions, so we should switch to
> something a bit more flexible that takes the matrix as an argument and
> programs the CSC accordingly.
> 
> Signed-off-by: Maxime Ripard <maxime at cerno.tech>

Acked-by: Thomas Zimmermann <tzimmermann at suse.de>

> ---
>   drivers/gpu/drm/vc4/vc4_hdmi.c | 77 +++++++++++++++++++++-------------
>   1 file changed, 48 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
> index b0e0cb533944..9614de7303b8 100644
> --- a/drivers/gpu/drm/vc4/vc4_hdmi.c
> +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
> @@ -525,6 +525,50 @@ static void vc4_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   	HDMI_WRITE(HDMI_CSC_CTL, csc_ctl);
>   }
>   
> +
> +/*
> + * If we need to output Full Range RGB, then use the unity matrix
> + *
> + * [ 1      0      0      0]
> + * [ 0      1      0      0]
> + * [ 0      0      1      0]
> + *
> + * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
> + */
> +static const u16 vc5_hdmi_csc_full_rgb_unity[3][4] = {
> +	{ 0x2000, 0x0000, 0x0000, 0x0000 },
> +	{ 0x0000, 0x2000, 0x0000, 0x0000 },
> +	{ 0x0000, 0x0000, 0x2000, 0x0000 },
> +};
> +
> +/*
> + * CEA VICs other than #1 require limited range RGB output unless
> + * overridden by an AVI infoframe. Apply a colorspace conversion to
> + * squash 0-255 down to 16-235. The matrix here is:
> + *
> + * [ 0.8594 0      0      16]
> + * [ 0      0.8594 0      16]
> + * [ 0      0      0.8594 16]
> + *
> + * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
> + */
> +static const u16 vc5_hdmi_csc_full_rgb_to_limited_rgb[3][4] = {
> +	{ 0x1b80, 0x0000, 0x0000, 0x0400 },
> +	{ 0x0000, 0x1b80, 0x0000, 0x0400 },
> +	{ 0x0000, 0x0000, 0x1b80, 0x0400 },
> +};
> +
> +static void vc5_hdmi_set_csc_coeffs(struct vc4_hdmi *vc4_hdmi,
> +				    const u16 coeffs[3][4])
> +{
> +	HDMI_WRITE(HDMI_CSC_12_11, (coeffs[0][1] << 16) | coeffs[0][0]);
> +	HDMI_WRITE(HDMI_CSC_14_13, (coeffs[0][3] << 16) | coeffs[0][2]);
> +	HDMI_WRITE(HDMI_CSC_22_21, (coeffs[1][1] << 16) | coeffs[1][0]);
> +	HDMI_WRITE(HDMI_CSC_24_23, (coeffs[1][3] << 16) | coeffs[1][2]);
> +	HDMI_WRITE(HDMI_CSC_32_31, (coeffs[2][1] << 16) | coeffs[2][0]);
> +	HDMI_WRITE(HDMI_CSC_34_33, (coeffs[2][3] << 16) | coeffs[2][2]);
> +}
> +
>   static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   			       const struct drm_display_mode *mode)
>   {
> @@ -533,35 +577,10 @@ static void vc5_hdmi_csc_setup(struct vc4_hdmi *vc4_hdmi,
>   
>   	HDMI_WRITE(HDMI_VEC_INTERFACE_XBAR, 0x354021);
>   
> -	if (vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode)) {
> -		/* CEA VICs other than #1 requre limited range RGB
> -		 * output unless overridden by an AVI infoframe.
> -		 * Apply a colorspace conversion to squash 0-255 down
> -		 * to 16-235.  The matrix here is:
> -		 *
> -		 * [ 0.8594 0      0      16]
> -		 * [ 0      0.8594 0      16]
> -		 * [ 0      0      0.8594 16]
> -		 * [ 0      0      0       1]
> -		 * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
> -		 */
> -		HDMI_WRITE(HDMI_CSC_12_11, (0x0000 << 16) | 0x1b80);
> -		HDMI_WRITE(HDMI_CSC_14_13, (0x0400 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_22_21, (0x1b80 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_24_23, (0x0400 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_32_31, (0x0000 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_34_33, (0x0400 << 16) | 0x1b80);
> -	} else {
> -		/* Still use the matrix for full range, but make it unity.
> -		 * Matrix is signed 2p13 fixed point, with signed 9p6 offsets
> -		 */
> -		HDMI_WRITE(HDMI_CSC_12_11, (0x0000 << 16) | 0x2000);
> -		HDMI_WRITE(HDMI_CSC_14_13, (0x0000 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_22_21, (0x2000 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_24_23, (0x0000 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_32_31, (0x0000 << 16) | 0x0000);
> -		HDMI_WRITE(HDMI_CSC_34_33, (0x0000 << 16) | 0x2000);
> -	}
> +	if (vc4_hdmi_is_full_range_rgb(vc4_hdmi, mode))
> +		vc5_hdmi_set_csc_coeffs(vc4_hdmi, &vc5_hdmi_csc_full_rgb_unity);
> +	else
> +		vc5_hdmi_set_csc_coeffs(vc4_hdmi, &vc5_hdmi_csc_full_rgb_to_limited_rgb);
>   
>   	HDMI_WRITE(HDMI_CSC_CTL, csc_ctl);
>   }
> 

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

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