Re: [Intel-gfx] [Intel-xe] [PATCH 17/42] drm/i915/xe2lpd: D2D Enable preserve bits in DDI_BUF_CTL

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

On Wed, 23 Aug 2023, Lucas De Marchi <lucas.demarchi@intel.com> wrote:
> From: Clint Taylor <clinton.a.taylor@intel.com>
>
> Display Ver 20 moved the D2D Enable bit to DDI_BUF_CTL(DDI_CTL_DE)
> register. We used multiple variables for HDMI and DisplayPort copies of
> this register. Consolidate the various locations to use
> intel_digital_port saved_port_bits.

All changes like this would be better off in two steps:

1) non-functional moving of the member to another struct

2) adding new stuff on top

The reason is two-fold: it's easier to review each step, and should a
bisect ever point at either of them regressing, it's easier to debug.


BR,
Jani.


>
> Cc: Anusha Srivatsa <anusha.srivatsa@intel.com>
> Cc: Gustavo Sousa <gustavo.sousa@intel.com>
> Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
> Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 40 +++++++++++++-----------
>  drivers/gpu/drm/i915/display/intel_dp.c  |  2 +-
>  2 files changed, 22 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index a9440c0ecf61..3147ed174d83 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -324,26 +324,25 @@ static void intel_ddi_init_dp_buf_reg(struct intel_encoder *encoder,
>  				      const struct intel_crtc_state *crtc_state)
>  {
>  	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);
>  	enum phy phy = intel_port_to_phy(i915, encoder->port);
>  
>  	/* DDI_BUF_CTL_ENABLE will be set by intel_ddi_prepare_link_retrain() later */
> -	intel_dp->DP = dig_port->saved_port_bits |
> +	dig_port->saved_port_bits |=
>  		DDI_PORT_WIDTH(crtc_state->lane_count) |
>  		DDI_BUF_TRANS_SELECT(0);
>  
>  	if (DISPLAY_VER(i915) >= 14) {
>  		if (intel_dp_is_uhbr(crtc_state))
> -			intel_dp->DP |= DDI_BUF_PORT_DATA_40BIT;
> +			dig_port->saved_port_bits |= DDI_BUF_PORT_DATA_40BIT;
>  		else
> -			intel_dp->DP |= DDI_BUF_PORT_DATA_10BIT;
> +			dig_port->saved_port_bits |= DDI_BUF_PORT_DATA_10BIT;
>  	}
>  
>  	if (IS_ALDERLAKE_P(i915) && intel_phy_is_tc(i915, phy)) {
> -		intel_dp->DP |= ddi_buf_phy_link_rate(crtc_state->port_clock);
> +		dig_port->saved_port_bits |= ddi_buf_phy_link_rate(crtc_state->port_clock);
>  		if (!intel_tc_port_in_tbt_alt_mode(dig_port))
> -			intel_dp->DP |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
> +			dig_port->saved_port_bits |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
>  	}
>  }
>  
> @@ -1449,7 +1448,7 @@ hsw_set_signal_levels(struct intel_encoder *encoder,
>  		      const struct intel_crtc_state *crtc_state)
>  {
>  	struct drm_i915_private *dev_priv = 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);
>  	int level = intel_ddi_level(encoder, crtc_state, 0);
>  	enum port port = encoder->port;
>  	u32 signal_levels;
> @@ -1466,10 +1465,10 @@ hsw_set_signal_levels(struct intel_encoder *encoder,
>  	drm_dbg_kms(&dev_priv->drm, "Using signal levels %08x\n",
>  		    signal_levels);
>  
> -	intel_dp->DP &= ~DDI_BUF_EMP_MASK;
> -	intel_dp->DP |= signal_levels;
> +	dig_port->saved_port_bits &= ~DDI_BUF_EMP_MASK;
> +	dig_port->saved_port_bits |= signal_levels;
>  
> -	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> +	intel_de_write(dev_priv, DDI_BUF_CTL(port), dig_port->saved_port_bits);
>  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
>  }
>  
> @@ -2355,6 +2354,7 @@ static void
>  mtl_ddi_enable_d2d(struct intel_encoder *encoder)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>  	enum port port = encoder->port;
>  	i915_reg_t reg;
>  	u32 set_bits, wait_bits;
> @@ -2362,6 +2362,7 @@ mtl_ddi_enable_d2d(struct intel_encoder *encoder)
>  	if (DISPLAY_VER(dev_priv) >= 20) {
>  		reg = DDI_BUF_CTL(port);
>  		set_bits = XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
> +		dig_port->saved_port_bits |= XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
>  		wait_bits = XE2LPD_DDI_BUF_D2D_LINK_STATE;
>  	} else {
>  		reg = XELPDP_PORT_BUF_CTL1(port);
> @@ -2817,6 +2818,7 @@ static void
>  mtl_ddi_disable_d2d_link(struct intel_encoder *encoder)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> +	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
>  	enum port port = encoder->port;
>  	i915_reg_t reg;
>  	u32 clr_bits, wait_bits;
> @@ -2824,6 +2826,7 @@ mtl_ddi_disable_d2d_link(struct intel_encoder *encoder)
>  	if (DISPLAY_VER(dev_priv) >= 20) {
>  		reg = DDI_BUF_CTL(port);
>  		clr_bits = XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
> +		dig_port->saved_port_bits &= ~XE2LPD_DDI_BUF_D2D_LINK_ENABLE;
>  		wait_bits = XE2LPD_DDI_BUF_D2D_LINK_STATE;
>  	} else {
>  		reg = XELPDP_PORT_BUF_CTL1(port);
> @@ -3162,7 +3165,6 @@ static void intel_enable_ddi_hdmi(struct intel_atomic_state *state,
>  	struct drm_connector *connector = conn_state->connector;
>  	enum port port = encoder->port;
>  	enum phy phy = intel_port_to_phy(dev_priv, port);
> -	u32 buf_ctl;
>  
>  	if (!intel_hdmi_handle_sink_scrambling(encoder, connector,
>  					       crtc_state->hdmi_high_tmds_clock_ratio,
> @@ -3228,7 +3230,7 @@ static void intel_enable_ddi_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 = dig_port->saved_port_bits | DDI_BUF_CTL_ENABLE;
> +	dig_port->saved_port_bits |= DDI_BUF_CTL_ENABLE;
>  	if (DISPLAY_VER(dev_priv) >= 14) {
>  		u8  lane_count = mtl_get_port_width(crtc_state->lane_count);
>  		u32 port_buf = 0;
> @@ -3241,13 +3243,13 @@ static void intel_enable_ddi_hdmi(struct intel_atomic_state *state,
>  		intel_de_rmw(dev_priv, XELPDP_PORT_BUF_CTL1(port),
>  			     XELPDP_PORT_WIDTH_MASK | XELPDP_PORT_REVERSAL, port_buf);
>  
> -		buf_ctl |= DDI_PORT_WIDTH(lane_count);
> +		dig_port->saved_port_bits |= DDI_PORT_WIDTH(lane_count);
>  	} else if (IS_ALDERLAKE_P(dev_priv) && intel_phy_is_tc(dev_priv, phy)) {
>  		drm_WARN_ON(&dev_priv->drm, !intel_tc_port_in_legacy_mode(dig_port));
> -		buf_ctl |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
> +		dig_port->saved_port_bits |= DDI_BUF_CTL_TC_PHY_OWNERSHIP;
>  	}
>  
> -	intel_de_write(dev_priv, DDI_BUF_CTL(port), buf_ctl);
> +	intel_de_write(dev_priv, DDI_BUF_CTL(port), dig_port->saved_port_bits);
>  
>  	intel_wait_ddi_buf_active(dev_priv, port);
>  
> @@ -3465,8 +3467,8 @@ 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;
> -	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> +	dig_port->saved_port_bits |= DDI_BUF_CTL_ENABLE;
> +	intel_de_write(dev_priv, DDI_BUF_CTL(port), dig_port->saved_port_bits);
>  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
>  
>  	/* 6.j Poll for PORT_BUF_CTL Idle Status == 0, timeout after 100 us */
> @@ -3516,8 +3518,8 @@ 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_dp->DP |= DDI_BUF_CTL_ENABLE;
> -	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> +	dig_port->saved_port_bits |= DDI_BUF_CTL_ENABLE;
> +	intel_de_write(dev_priv, DDI_BUF_CTL(port), dig_port->saved_port_bits);
>  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
>  
>  	intel_wait_ddi_buf_active(dev_priv, port);
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index 84584864511b..334789be0054 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -5631,7 +5631,7 @@ intel_dp_init_connector(struct intel_digital_port *dig_port,
>  	intel_dp->pps.active_pipe = INVALID_PIPE;
>  
>  	/* Preserve the current hw state. */
> -	intel_dp->DP = intel_de_read(dev_priv, intel_dp->output_reg);
> +	dig_port->saved_port_bits = intel_de_read(dev_priv, intel_dp->output_reg);
>  	intel_dp->attached_connector = intel_connector;
>  
>  	if (_intel_dp_is_port_edp(dev_priv, intel_encoder->devdata, port)) {

-- 
Jani Nikula, Intel Open Source Graphics Center