Re: [PATCH 10/17] drm/i915/ddi: Add a helper to enable a port

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 29 Jan 2025, Imre Deak <imre.deak@intel.com> wrote:
> Add a helper to enable a port instead of open-coding it.
>
> Signed-off-by: Imre Deak <imre.deak@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 34 +++++++++++-------------
>  1 file changed, 16 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index 73702ccbb3773..ddb182550ad0f 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -3057,6 +3057,17 @@ mtl_ddi_disable_d2d_link(struct intel_encoder *encoder)
>  			port_name(port));
>  }
>  
> +static void intel_enable_ddi_buf(struct intel_encoder *encoder, u32 buf_ctl)

This is in line with current code, but I'd use intel_ddi_buf_enable()
instead.

> +{
> +	struct intel_display *display = to_intel_display(encoder);
> +	enum port port = encoder->port;
> +
> +	intel_de_write(display, DDI_BUF_CTL(port), buf_ctl | DDI_BUF_CTL_ENABLE);
> +	intel_de_posting_read(display, DDI_BUF_CTL(port));
> +
> +	intel_wait_ddi_buf_active(encoder);
> +}
> +
>  static void intel_disable_ddi_buf(struct intel_encoder *encoder,
>  				  const struct intel_crtc_state *crtc_state)
>  {
> @@ -3375,7 +3386,7 @@ static void intel_ddi_enable_hdmi(struct intel_atomic_state *state,
>  	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>  	struct drm_connector *connector = conn_state->connector;
>  	enum port port = encoder->port;
> -	u32 buf_ctl;
> +	u32 buf_ctl = 0;
>  
>  	if (!intel_hdmi_handle_sink_scrambling(encoder, connector,
>  					       crtc_state->hdmi_high_tmds_clock_ratio,
> @@ -3440,8 +3451,6 @@ static void intel_ddi_enable_hdmi(struct intel_atomic_state *state,
>  	 * is filled with lane count, already set in the crtc_state.
>  	 * The same is required to be filled in PORT_BUF_CTL for C10/20 Phy.
>  	 */
> -	buf_ctl = DDI_BUF_CTL_ENABLE;
> -
>  	if (dig_port->lane_reversal)
>  		buf_ctl |= DDI_BUF_PORT_REVERSAL;
>  	if (dig_port->ddi_a_4_lanes)
> @@ -3467,9 +3476,7 @@ static void intel_ddi_enable_hdmi(struct intel_atomic_state *state,
>  		buf_ctl |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
>  	}
>  
> -	intel_de_write(dev_priv, DDI_BUF_CTL(port), buf_ctl);
> -
> -	intel_wait_ddi_buf_active(encoder);
> +	intel_enable_ddi_buf(encoder, buf_ctl);
>  }
>  
>  static void intel_ddi_enable(struct intel_atomic_state *state,
> @@ -3692,7 +3699,6 @@ static void mtl_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
>  	struct intel_display *display = to_intel_display(crtc_state);
>  	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>  	struct intel_encoder *encoder = &dig_port->base;
> -	enum port port = encoder->port;
>  	u32 dp_tp_ctl;
>  
>  	/*
> @@ -3726,15 +3732,11 @@ static void mtl_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
>  	mtl_port_buf_ctl_program(encoder, crtc_state);
>  
>  	/* 6.i Configure and enable DDI_CTL_DE to start sending valid data to port slice */
> -	intel_dp->DP |= DDI_BUF_CTL_ENABLE;
>  	if (DISPLAY_VER(display) >= 20)
>  		intel_dp->DP |= XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
>  
> -	intel_de_write(display, DDI_BUF_CTL(port), intel_dp->DP);
> -	intel_de_posting_read(display, DDI_BUF_CTL(port));
> -
> -	/* 6.j Poll for PORT_BUF_CTL Idle Status == 0, timeout after 100 us */
> -	intel_wait_ddi_buf_active(encoder);
> +	intel_enable_ddi_buf(encoder, intel_dp->DP);
> +	intel_dp->DP |= DDI_BUF_CTL_ENABLE;

I hate this last line, but that's another story.

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


>  }
>  
>  static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
> @@ -3743,7 +3745,6 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
>  	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>  	struct intel_encoder *encoder = &dig_port->base;
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> -	enum port port = encoder->port;
>  	u32 dp_tp_ctl;
>  
>  	dp_tp_ctl = intel_de_read(dev_priv, dp_tp_ctl_reg(encoder, crtc_state));
> @@ -3766,11 +3767,8 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp,
>  	    (intel_tc_port_in_dp_alt_mode(dig_port) || intel_tc_port_in_legacy_mode(dig_port)))
>  		adlp_tbt_to_dp_alt_switch_wa(encoder);
>  
> +	intel_enable_ddi_buf(encoder, intel_dp->DP);
>  	intel_dp->DP |= DDI_BUF_CTL_ENABLE;
> -	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> -	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
> -
> -	intel_wait_ddi_buf_active(encoder);
>  }
>  
>  static void intel_ddi_set_link_train(struct intel_dp *intel_dp,

-- 
Jani Nikula, Intel