drm/i915: Pimp HSW+ transcoder state readout

Adjust the HSW+ transcoder state readout to just read through
all the possible transcoders for the pipe, and stuff the results
in a bitmask.

We can conveniently cross check the bitmask for invalid
combinations of enabled transcoders, and later we can easily
extend the bitmask readout to handle the bigjoiner case.

One slight change in behaviour is that we no longer read out
the AONOFF->force_pfit.pfit bit for all the enabled "panel
transcoders". But having more than one enabled would anyway
be illegal so no big loss. Also the AONOFF selection should
only ever be used on HSW, which only has the EDP transcoder
an no DSI transcoders.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210913144440.23008-10-ville.syrjala@linux.intel.comReviewed-by: Manasi Navare <manasi.d.navare@intel.com>

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

@@ -5724,6 +5724,21 @@ static bool ilk_get_pipe_config(struct intel_crtc *crtc,
 	return ret;
 }
 
+static bool transcoder_ddi_func_is_enabled(struct drm_i915_private *dev_priv,
+					   enum transcoder cpu_transcoder)
+{
+	enum intel_display_power_domain power_domain;
+	intel_wakeref_t wakeref;
+	u32 tmp = 0;
+
+	power_domain = POWER_DOMAIN_TRANSCODER(cpu_transcoder);
+
+	with_intel_display_power_if_enabled(dev_priv, power_domain, wakeref)
+		tmp = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
+
+	return tmp & TRANS_DDI_FUNC_ENABLE;
+}
+
 static u8 hsw_panel_transcoders(struct drm_i915_private *i915)
 {
 	u8 panel_transcoder_mask = BIT(TRANSCODER_EDP);
@@ -5734,55 +5749,39 @@ static u8 hsw_panel_transcoders(struct drm_i915_private *i915)
 	return panel_transcoder_mask;
 }
 
-static bool hsw_get_transcoder_state(struct intel_crtc *crtc,
-				     struct intel_crtc_state *pipe_config,
-				     struct intel_display_power_domain_set *power_domain_set)
+static u8 hsw_enabled_transcoders(struct intel_crtc *crtc)
 {
 	struct drm_device *dev = crtc->base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	u8 panel_transcoder_mask = hsw_panel_transcoders(dev_priv);
-	unsigned long enabled_panel_transcoders = 0;
-	enum transcoder panel_transcoder;
-	u32 tmp;
-
-	/*
-	 * The pipe->transcoder mapping is fixed with the exception of the eDP
-	 * and DSI transcoders handled below.
-	 */
-	pipe_config->cpu_transcoder = (enum transcoder) crtc->pipe;
+	enum transcoder cpu_transcoder;
+	u8 enabled_transcoders = 0;
 
 	/*
 	 * XXX: Do intel_display_power_get_if_enabled before reading this (for
 	 * consistency and less surprising code; it's in always on power).
 	 */
-	for_each_cpu_transcoder_masked(dev_priv, panel_transcoder,
+	for_each_cpu_transcoder_masked(dev_priv, cpu_transcoder,
 				       panel_transcoder_mask) {
-		bool force_thru = false;
+		enum intel_display_power_domain power_domain;
+		intel_wakeref_t wakeref;
 		enum pipe trans_pipe;
+		u32 tmp = 0;
 
-		tmp = intel_de_read(dev_priv,
-				    TRANS_DDI_FUNC_CTL(panel_transcoder));
-		if (!(tmp & TRANS_DDI_FUNC_ENABLE))
-			continue;
+		power_domain = POWER_DOMAIN_TRANSCODER(cpu_transcoder);
+		with_intel_display_power_if_enabled(dev_priv, power_domain, wakeref)
+			tmp = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(cpu_transcoder));
 
-		/*
-		 * Log all enabled ones, only use the first one.
-		 *
-		 * FIXME: This won't work for two separate DSI displays.
-		 */
-		enabled_panel_transcoders |= BIT(panel_transcoder);
-		if (enabled_panel_transcoders != BIT(panel_transcoder))
+		if (!(tmp & TRANS_DDI_FUNC_ENABLE))
 			continue;
 
 		switch (tmp & TRANS_DDI_EDP_INPUT_MASK) {
 		default:
 			drm_WARN(dev, 1,
 				 "unknown pipe linked to transcoder %s\n",
-				 transcoder_name(panel_transcoder));
+				 transcoder_name(cpu_transcoder));
 			fallthrough;
 		case TRANS_DDI_EDP_INPUT_A_ONOFF:
-			force_thru = true;
-			fallthrough;
 		case TRANS_DDI_EDP_INPUT_A_ON:
 			trans_pipe = PIPE_A;
 			break;
@@ -5797,22 +5796,83 @@ static bool hsw_get_transcoder_state(struct intel_crtc *crtc,
 			break;
 		}
 
-		if (trans_pipe == crtc->pipe) {
-			pipe_config->cpu_transcoder = panel_transcoder;
-			pipe_config->pch_pfit.force_thru = force_thru;
-		}
+		if (trans_pipe == crtc->pipe)
+			enabled_transcoders |= BIT(cpu_transcoder);
 	}
 
+	cpu_transcoder = (enum transcoder) crtc->pipe;
+	if (transcoder_ddi_func_is_enabled(dev_priv, cpu_transcoder))
+		enabled_transcoders |= BIT(cpu_transcoder);
+
+	return enabled_transcoders;
+}
+
+static bool has_edp_transcoders(u8 enabled_transcoders)
+{
+	return enabled_transcoders & BIT(TRANSCODER_EDP);
+}
+
+static bool has_dsi_transcoders(u8 enabled_transcoders)
+{
+	return enabled_transcoders & (BIT(TRANSCODER_DSI_0) |
+				      BIT(TRANSCODER_DSI_1));
+}
+
+static bool has_pipe_transcoders(u8 enabled_transcoders)
+{
+	return enabled_transcoders & ~(BIT(TRANSCODER_EDP) |
+				       BIT(TRANSCODER_DSI_0) |
+				       BIT(TRANSCODER_DSI_1));
+}
+
+static void assert_enabled_transcoders(struct drm_i915_private *i915,
+				       u8 enabled_transcoders)
+{
+	/* Only one type of transcoder please */
+	drm_WARN_ON(&i915->drm,
+		    has_edp_transcoders(enabled_transcoders) +
+		    has_dsi_transcoders(enabled_transcoders) +
+		    has_pipe_transcoders(enabled_transcoders) > 1);
+
+	/* Only DSI transcoders can be ganged */
+	drm_WARN_ON(&i915->drm,
+		    !has_dsi_transcoders(enabled_transcoders) &&
+		    !is_power_of_2(enabled_transcoders));
+}
+
+static bool hsw_get_transcoder_state(struct intel_crtc *crtc,
+				     struct intel_crtc_state *pipe_config,
+				     struct intel_display_power_domain_set *power_domain_set)
+{
+	struct drm_device *dev = crtc->base.dev;
+	struct drm_i915_private *dev_priv = to_i915(dev);
+	unsigned long enabled_transcoders;
+	u32 tmp;
+
+	enabled_transcoders = hsw_enabled_transcoders(crtc);
+	if (!enabled_transcoders)
+		return false;
+
+	assert_enabled_transcoders(dev_priv, enabled_transcoders);
+
 	/*
-	 * Valid combos: none, eDP, DSI0, DSI1, DSI0+DSI1
+	 * With the exception of DSI we should only ever have
+	 * a single enabled transcoder. With DSI let's just
+	 * pick the first one.
 	 */
-	drm_WARN_ON(dev, (enabled_panel_transcoders & BIT(TRANSCODER_EDP)) &&
-		    enabled_panel_transcoders != BIT(TRANSCODER_EDP));
+	pipe_config->cpu_transcoder = ffs(enabled_transcoders) - 1;
 
 	if (!intel_display_power_get_in_set_if_enabled(dev_priv, power_domain_set,
 						       POWER_DOMAIN_TRANSCODER(pipe_config->cpu_transcoder)))
 		return false;
 
+	if (hsw_panel_transcoders(dev_priv) & BIT(pipe_config->cpu_transcoder)) {
+		tmp = intel_de_read(dev_priv, TRANS_DDI_FUNC_CTL(pipe_config->cpu_transcoder));
+
+		if ((tmp & TRANS_DDI_EDP_INPUT_MASK) == TRANS_DDI_EDP_INPUT_A_ONOFF)
+			pipe_config->pch_pfit.force_thru = true;
+	}
+
 	tmp = intel_de_read(dev_priv, PIPECONF(pipe_config->cpu_transcoder));
 
 	return tmp & PIPECONF_ENABLE;