drm/i915/xelpd: Add VRR guardband for VRR CTL

On XE_LPD, VRR CTL register adds a new VRR Guardband bitfield
replacing the pipeline full and deprecating the pipeline override
bit.

This patch adds this corresponding bitfield in the register defs,
crtc state vrr structure and populates this in vrr compute
config and vrr enable functions. It also adds the corresponding
HW state readout for this field.

Bspec: 50508
Cc: Aditya Swarup <aditya.swarup@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Aditya Swarup <aditya.swarup@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210526000656.3060314-3-matthew.d.roper@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -7654,10 +7654,11 @@ static void intel_dump_pipe_config(const struct intel_crtc_state *pipe_config,
 	    intel_hdmi_infoframe_enable(DP_SDP_VSC))
 		intel_dump_dp_vsc_sdp(dev_priv, &pipe_config->infoframes.vsc);
 
-	drm_dbg_kms(&dev_priv->drm, "vrr: %s, vmin: %d, vmax: %d, pipeline full: %d, flipline: %d, vmin vblank: %d, vmax vblank: %d\n",
+	drm_dbg_kms(&dev_priv->drm, "vrr: %s, vmin: %d, vmax: %d, pipeline full: %d, guardband: %d flipline: %d, vmin vblank: %d, vmax vblank: %d\n",
 		    yesno(pipe_config->vrr.enable),
 		    pipe_config->vrr.vmin, pipe_config->vrr.vmax,
-		    pipe_config->vrr.pipeline_full, pipe_config->vrr.flipline,
+		    pipe_config->vrr.pipeline_full, pipe_config->vrr.guardband,
+		    pipe_config->vrr.flipline,
 		    intel_vrr_vmin_vblank_start(pipe_config),
 		    intel_vrr_vmax_vblank_start(pipe_config));
 
@@ -8663,6 +8664,7 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
 	PIPE_CONF_CHECK_I(vrr.vmax);
 	PIPE_CONF_CHECK_I(vrr.flipline);
 	PIPE_CONF_CHECK_I(vrr.pipeline_full);
+	PIPE_CONF_CHECK_I(vrr.guardband);
 
 	PIPE_CONF_CHECK_BOOL(has_psr);
 	PIPE_CONF_CHECK_BOOL(has_psr2);
@@ -12256,6 +12258,8 @@ int intel_modeset_init_noirq(struct drm_i915_private *i915)
 
 	i915->framestart_delay = 1; /* 1-4 */
 
+	i915->window2_delay = 0; /* No DSB so no window2 delay */
+
 	intel_mode_config_init(i915);
 
 	ret = intel_cdclk_init(i915);

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -1202,7 +1202,7 @@ struct intel_crtc_state {
 	struct {
 		bool enable;
 		u8 pipeline_full;
-		u16 flipline, vmin, vmax;
+		u16 flipline, vmin, vmax, guardband;
 	} vrr;
 
 	/* Stream Splitter for eDP MSO */

drivers/gpu/drm/i915/display/intel_vrr.c

@@ -68,7 +68,10 @@ static int intel_vrr_vblank_exit_length(const struct intel_crtc_state *crtc_stat
 	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
 
 	/* The hw imposes the extra scanline before frame start */
-	return crtc_state->vrr.pipeline_full + i915->framestart_delay + 1;
+	if (DISPLAY_VER(i915) >= 13)
+		return crtc_state->vrr.guardband + i915->framestart_delay + 1;
+	else
+		return crtc_state->vrr.pipeline_full + i915->framestart_delay + 1;
 }
 
 int intel_vrr_vmin_vblank_start(const struct intel_crtc_state *crtc_state)
@@ -86,6 +89,8 @@ void
 intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
 			 struct drm_connector_state *conn_state)
 {
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
 	struct intel_connector *connector =
 		to_intel_connector(conn_state->connector);
 	struct drm_display_mode *adjusted_mode = &crtc_state->hw.adjusted_mode;
@@ -124,17 +129,26 @@ intel_vrr_compute_config(struct intel_crtc_state *crtc_state,
 	crtc_state->vrr.flipline = crtc_state->vrr.vmin + 1;
 
 	/*
-	 * FIXME: s/4/framestart_delay+1/ to get consistent
+	 * For XE_LPD+, we use guardband and pipeline override
-	 * earliest/latest points for register latching regardless
+	 * is deprecated.
-	 * of the framestart_delay used?
-	 *
-	 * FIXME: this really needs the extra scanline to provide consistent
-	 * behaviour for all framestart_delay values. Otherwise with
-	 * framestart_delay==3 we will end up extending the min vblank by
-	 * one extra line.
 	 */
-	crtc_state->vrr.pipeline_full =
+	if (DISPLAY_VER(i915) >= 13)
-		min(255, crtc_state->vrr.vmin - adjusted_mode->crtc_vdisplay - 4 - 1);
+		crtc_state->vrr.guardband =
+			crtc_state->vrr.vmin - adjusted_mode->crtc_vdisplay -
+			i915->window2_delay;
+	else
+		/*
+		 * FIXME: s/4/framestart_delay+1/ to get consistent
+		 * earliest/latest points for register latching regardless
+		 * of the framestart_delay used?
+		 *
+		 * FIXME: this really needs the extra scanline to provide consistent
+		 * behaviour for all framestart_delay values. Otherwise with
+		 * framestart_delay==3 we will end up extending the min vblank by
+		 * one extra line.
+		 */
+		crtc_state->vrr.pipeline_full =
+			min(255, crtc_state->vrr.vmin - adjusted_mode->crtc_vdisplay - 4 - 1);
 
 	crtc_state->mode_flags |= I915_MODE_FLAG_VRR;
 }
@@ -149,10 +163,15 @@ void intel_vrr_enable(struct intel_encoder *encoder,
 	if (!crtc_state->vrr.enable)
 		return;
 
-	trans_vrr_ctl = VRR_CTL_VRR_ENABLE |
+	if (DISPLAY_VER(dev_priv) >= 13)
-		VRR_CTL_IGN_MAX_SHIFT | VRR_CTL_FLIP_LINE_EN |
+		trans_vrr_ctl = VRR_CTL_VRR_ENABLE |
-		VRR_CTL_PIPELINE_FULL(crtc_state->vrr.pipeline_full) |
+			VRR_CTL_IGN_MAX_SHIFT | VRR_CTL_FLIP_LINE_EN |
-		VRR_CTL_PIPELINE_FULL_OVERRIDE;
+			XELPD_VRR_CTL_VRR_GUARDBAND(crtc_state->vrr.guardband);
+	else
+		trans_vrr_ctl = VRR_CTL_VRR_ENABLE |
+			VRR_CTL_IGN_MAX_SHIFT | VRR_CTL_FLIP_LINE_EN |
+			VRR_CTL_PIPELINE_FULL(crtc_state->vrr.pipeline_full) |
+			VRR_CTL_PIPELINE_FULL_OVERRIDE;
 
 	intel_de_write(dev_priv, TRANS_VRR_VMIN(cpu_transcoder), crtc_state->vrr.vmin - 1);
 	intel_de_write(dev_priv, TRANS_VRR_VMAX(cpu_transcoder), crtc_state->vrr.vmax - 1);
@@ -199,8 +218,13 @@ void intel_vrr_get_config(struct intel_crtc *crtc,
 	if (!crtc_state->vrr.enable)
 		return;
 
-	if (trans_vrr_ctl & VRR_CTL_PIPELINE_FULL_OVERRIDE)
+	if (DISPLAY_VER(dev_priv) >= 13)
-		crtc_state->vrr.pipeline_full = REG_FIELD_GET(VRR_CTL_PIPELINE_FULL_MASK, trans_vrr_ctl);
+		crtc_state->vrr.guardband =
+			REG_FIELD_GET(XELPD_VRR_CTL_VRR_GUARDBAND_MASK, trans_vrr_ctl);
+	else
+		if (trans_vrr_ctl & VRR_CTL_PIPELINE_FULL_OVERRIDE)
+			crtc_state->vrr.pipeline_full =
+				REG_FIELD_GET(VRR_CTL_PIPELINE_FULL_MASK, trans_vrr_ctl);
 	if (trans_vrr_ctl & VRR_CTL_FLIP_LINE_EN)
 		crtc_state->vrr.flipline = intel_de_read(dev_priv, TRANS_VRR_FLIPLINE(cpu_transcoder)) + 1;
 	crtc_state->vrr.vmax = intel_de_read(dev_priv, TRANS_VRR_VMAX(cpu_transcoder)) + 1;

drivers/gpu/drm/i915/i915_drv.h

@@ -1133,6 +1133,9 @@ struct drm_i915_private {
 
 	u8 framestart_delay;
 
+	/* Window2 specifies time required to program DSB (Window2) in number of scan lines */
+	u8 window2_delay;
+
 	u8 pch_ssc_use;
 
 	/* For i915gm/i945gm vblank irq workaround */

drivers/gpu/drm/i915/i915_reg.h

@@ -4379,6 +4379,8 @@ enum {
 #define   VRR_CTL_PIPELINE_FULL_MASK		REG_GENMASK(10, 3)
 #define   VRR_CTL_PIPELINE_FULL(x)		REG_FIELD_PREP(VRR_CTL_PIPELINE_FULL_MASK, (x))
 #define   VRR_CTL_PIPELINE_FULL_OVERRIDE	REG_BIT(0)
+#define	  XELPD_VRR_CTL_VRR_GUARDBAND_MASK	REG_GENMASK(15, 0)
+#define	  XELPD_VRR_CTL_VRR_GUARDBAND(x)	REG_FIELD_PREP(XELPD_VRR_CTL_VRR_GUARDBAND_MASK, (x))
 
 #define _TRANS_VRR_VMAX_A		0x60424
 #define _TRANS_VRR_VMAX_B		0x61424