drm/i915/dsc: abstract helpers to get bigjoiner primary/secondary crtc

Add a single point of truth for figuring out the primary/secondary crtc
for bigjoiner instead of duplicating the magic pipe +/- 1 in multiple
places.

Also fix the pipe validity checks to properly take non-contiguous pipes
into account. The current checks may theoretically overflow
i915->pipe_to_crtc_mapping[pipe], albeit with a warning, due to fused
off pipes, as INTEL_NUM_PIPES() returns the actual number of pipes on
the platform, and the check is for INTEL_NUM_PIPES() == pipe + 1.

Prefer primary/secondary terminology going forward.

v2:
- Improved abstractions for pipe validity etc.

Fixes: 8a029c1 ("drm/i915/dp: Modify VDSC helpers to configure DSC for Bigjoiner slave")
Fixes: d961eb2 ("drm/i915/bigjoiner: atomic commit changes for uncompressed joiner")
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Reviewed-by: Manasi Navare <manasi.dl.navare@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210610090528.20511-1-jani.nikula@intel.com
(cherry picked from commit 1720322)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Author: jnikula

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

@@ -9618,7 +9618,6 @@ static int intel_atomic_check_bigjoiner(struct intel_atomic_state *state,
 					struct intel_crtc_state *old_crtc_state,
 					struct intel_crtc_state *new_crtc_state)
 {
-	struct drm_i915_private *dev_priv = to_i915(state->base.dev);
 	struct intel_crtc_state *slave_crtc_state, *master_crtc_state;
 	struct intel_crtc *slave, *master;
 
@@ -9634,15 +9633,15 @@ static int intel_atomic_check_bigjoiner(struct intel_atomic_state *state,
 	if (!new_crtc_state->bigjoiner)
 		return 0;
 
-	if (1 + crtc->pipe >= INTEL_NUM_PIPES(dev_priv)) {
+	slave = intel_dsc_get_bigjoiner_secondary(crtc);
+	if (!slave) {
 		DRM_DEBUG_KMS("[CRTC:%d:%s] Big joiner configuration requires "
 			      "CRTC + 1 to be used, doesn't exist\n",
 			      crtc->base.base.id, crtc->base.name);
 		return -EINVAL;
 	}
 
-	slave = new_crtc_state->bigjoiner_linked_crtc =
-		intel_get_crtc_for_pipe(dev_priv, crtc->pipe + 1);
+	new_crtc_state->bigjoiner_linked_crtc = slave;
 	slave_crtc_state = intel_atomic_get_crtc_state(&state->base, slave);
 	master = crtc;
 	if (IS_ERR(slave_crtc_state))

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

@@ -1723,6 +1723,14 @@ vlv_pipe_to_channel(enum pipe pipe)
 	}
 }
 
+static inline bool intel_pipe_valid(struct drm_i915_private *i915, enum pipe pipe)
+{
+	return (pipe >= 0 &&
+		pipe < ARRAY_SIZE(i915->pipe_to_crtc_mapping) &&
+		INTEL_INFO(i915)->pipe_mask & BIT(pipe) &&
+		i915->pipe_to_crtc_mapping[pipe]);
+}
+
 static inline struct intel_crtc *
 intel_get_first_crtc(struct drm_i915_private *dev_priv)
 {

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

@@ -1106,6 +1106,27 @@ static i915_reg_t dss_ctl2_reg(const struct intel_crtc_state *crtc_state)
 	return is_pipe_dsc(crtc_state) ? ICL_PIPE_DSS_CTL2(pipe) : DSS_CTL2;
 }
 
+static struct intel_crtc *
+_get_crtc_for_pipe(struct drm_i915_private *i915, enum pipe pipe)
+{
+	if (!intel_pipe_valid(i915, pipe))
+		return NULL;
+
+	return intel_get_crtc_for_pipe(i915, pipe);
+}
+
+struct intel_crtc *
+intel_dsc_get_bigjoiner_secondary(const struct intel_crtc *primary_crtc)
+{
+	return _get_crtc_for_pipe(to_i915(primary_crtc->base.dev), primary_crtc->pipe + 1);
+}
+
+static struct intel_crtc *
+intel_dsc_get_bigjoiner_primary(const struct intel_crtc *secondary_crtc)
+{
+	return _get_crtc_for_pipe(to_i915(secondary_crtc->base.dev), secondary_crtc->pipe - 1);
+}
+
 void intel_uncompressed_joiner_enable(const struct intel_crtc_state *crtc_state)
 {
 	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
@@ -1178,15 +1199,13 @@ void intel_uncompressed_joiner_get_config(struct intel_crtc_state *crtc_state)
 	dss_ctl1 = intel_de_read(dev_priv, dss_ctl1_reg(crtc_state));
 	if (dss_ctl1 & UNCOMPRESSED_JOINER_MASTER) {
 		crtc_state->bigjoiner = true;
-		if (!WARN_ON(INTEL_NUM_PIPES(dev_priv) == crtc->pipe + 1))
-			crtc_state->bigjoiner_linked_crtc =
-				intel_get_crtc_for_pipe(dev_priv, crtc->pipe + 1);
+		crtc_state->bigjoiner_linked_crtc = intel_dsc_get_bigjoiner_secondary(crtc);
+		drm_WARN_ON(&dev_priv->drm, !crtc_state->bigjoiner_linked_crtc);
 	} else if (dss_ctl1 & UNCOMPRESSED_JOINER_SLAVE) {
 		crtc_state->bigjoiner = true;
 		crtc_state->bigjoiner_slave = true;
-		if (!WARN_ON(crtc->pipe == PIPE_A))
-			crtc_state->bigjoiner_linked_crtc =
-				intel_get_crtc_for_pipe(dev_priv, crtc->pipe - 1);
+		crtc_state->bigjoiner_linked_crtc = intel_dsc_get_bigjoiner_primary(crtc);
+		drm_WARN_ON(&dev_priv->drm, !crtc_state->bigjoiner_linked_crtc);
 	}
 }
 
@@ -1224,14 +1243,11 @@ void intel_dsc_get_config(struct intel_crtc_state *crtc_state)
 
 		if (!(dss_ctl1 & MASTER_BIG_JOINER_ENABLE)) {
 			crtc_state->bigjoiner_slave = true;
-			if (!WARN_ON(crtc->pipe == PIPE_A))
-				crtc_state->bigjoiner_linked_crtc =
-					intel_get_crtc_for_pipe(dev_priv, crtc->pipe - 1);
+			crtc_state->bigjoiner_linked_crtc = intel_dsc_get_bigjoiner_primary(crtc);
 		} else {
-			if (!WARN_ON(INTEL_NUM_PIPES(dev_priv) == crtc->pipe + 1))
-				crtc_state->bigjoiner_linked_crtc =
-					intel_get_crtc_for_pipe(dev_priv, crtc->pipe + 1);
+			crtc_state->bigjoiner_linked_crtc = intel_dsc_get_bigjoiner_secondary(crtc);
 		}
+		drm_WARN_ON(&dev_priv->drm, !crtc_state->bigjoiner_linked_crtc);
 	}
 
 	/* FIXME: add more state readout as needed */

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

@@ -22,5 +22,6 @@ void intel_uncompressed_joiner_get_config(struct intel_crtc_state *crtc_state);
 void intel_dsc_get_config(struct intel_crtc_state *crtc_state);
 enum intel_display_power_domain
 intel_dsc_power_domain(const struct intel_crtc_state *crtc_state);
+struct intel_crtc *intel_dsc_get_bigjoiner_secondary(const struct intel_crtc *primary_crtc);
 
 #endif /* __INTEL_VDSC_H__ */