[PATCH 13/17] drm/i915/ddi: Factor out a helper to get DDI_BUF_CTL's config value

[Jani Nikula]

On Wed, 29 Jan 2025, Imre Deak <imre.deak at intel.com> wrote:
> Factor out a function to get the configuration fields in the DDI_BUF_CTL
> register. This can be used for configuring an HDMI output as well.
>
> Signed-off-by: Imre Deak <imre.deak at intel.com>

Reviewed-by: Jani Nikula <jani.nikula at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 32 ++++++++++++++++--------
>  1 file changed, 21 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 64c42505f2ad6..dd8ae5cf96c70 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -333,45 +333,55 @@ static int dp_phy_lane_stagger_delay(int port_clock)
>  	return DIV_ROUND_UP(port_clock, intel_dp_link_symbol_size(port_clock) * 1000);
>  }
>  
> -static void intel_ddi_init_dp_buf_reg(struct intel_encoder *encoder,
> -				      const struct intel_crtc_state *crtc_state)
> +static u32 intel_ddi_buf_ctl_config_val(struct intel_encoder *encoder,
> +					const struct intel_crtc_state *crtc_state)
>  {
>  	struct intel_display *display = to_intel_display(encoder);
>  	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> -	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
>  	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
> +	u32 val = 0;
>  
>  	/* DDI_BUF_CTL_ENABLE will be set by intel_ddi_prepare_link_retrain() later */
> -	intel_dp->DP = DDI_PORT_WIDTH(crtc_state->lane_count) |
> +	val |= DDI_PORT_WIDTH(crtc_state->lane_count) |
>  		DDI_BUF_TRANS_SELECT(0);
>  
>  	if (dig_port->lane_reversal)
> -		intel_dp->DP |= DDI_BUF_PORT_REVERSAL;
> +		val |= DDI_BUF_PORT_REVERSAL;
>  	if (dig_port->ddi_a_4_lanes)
> -		intel_dp->DP |= DDI_A_4_LANES;
> +		val |= DDI_A_4_LANES;
>  
>  	if (DISPLAY_VER(i915) >= 14) {
>  		if (intel_dp_is_uhbr(crtc_state))
> -			intel_dp->DP |= DDI_BUF_PORT_DATA_40BIT;
> +			val |= DDI_BUF_PORT_DATA_40BIT;
>  		else
> -			intel_dp->DP |= DDI_BUF_PORT_DATA_10BIT;
> +			val |= DDI_BUF_PORT_DATA_10BIT;
>  	}
>  
>  	if (IS_ALDERLAKE_P(i915) && intel_encoder_is_tc(encoder)) {
> -		intel_dp->DP |= ddi_buf_phy_link_rate(crtc_state->port_clock);
> +		val |= ddi_buf_phy_link_rate(crtc_state->port_clock);
>  		/*
>  		 * TODO: remove the following once DDI_BUF_CTL is updated via
>  		 * an RMW everywhere.
>  		 */
>  		if (!intel_tc_port_in_tbt_alt_mode(dig_port))
> -			intel_dp->DP |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
> +			val |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
>  	}
>  
>  	if (IS_DISPLAY_VER(display, 11, 13) && intel_encoder_is_tc(encoder)) {
>  		int delay = dp_phy_lane_stagger_delay(crtc_state->port_clock);
>  
> -		intel_dp->DP |= DDI_BUF_LANE_STAGGER_DELAY(delay);
> +		val |= DDI_BUF_LANE_STAGGER_DELAY(delay);
>  	}
> +
> +	return val;
> +}
> +
> +static void intel_ddi_init_dp_buf_reg(struct intel_encoder *encoder,
> +				      const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
> +
> +	intel_dp->DP = intel_ddi_buf_ctl_config_val(encoder, crtc_state);
>  }
>  
>  static u32 intel_ddi_buf_ctl_config_mask(struct intel_encoder *encoder)

-- 
Jani Nikula, Intel