[PATCH 4/4] drm/i915: Extract drm_dp_atomic_find_vcpi_slots cycle to separate function

[Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>]

We are using almost same code to loop through bpps while calling
drm_dp_atomic_find_vcpi_slots - lets remove this duplication by
introducing a new function intel_dp_mst_find_vcpi_slots_for_bpp

v2: Fix pbn_div calculation - shouldn't matter if its DSC or not.

Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_mst.c | 86 +++++++++++----------
 1 file changed, 45 insertions(+), 41 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 94d7e7f84c51..7dcbdcd1cb48 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -44,10 +44,14 @@
 #include "intel_hotplug.h"
 #include "skl_scaler.h"
 
-static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
-					    struct intel_crtc_state *crtc_state,
-					    struct drm_connector_state *conn_state,
-					    struct link_config_limits *limits)
+static int intel_dp_mst_find_vcpi_slots_for_bpp(struct intel_encoder *encoder,
+						struct intel_crtc_state *crtc_state,
+						int max_bpp,
+						int min_bpp,
+						struct link_config_limits *limits,
+						struct drm_connector_state *conn_state,
+						int step,
+						bool dsc)
 {
 	struct drm_atomic_state *state = crtc_state->uapi.state;
 	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
@@ -58,7 +62,6 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 	const struct drm_display_mode *adjusted_mode =
 		&crtc_state->hw.adjusted_mode;
-	bool constant_n = drm_dp_has_quirk(&intel_dp->desc, DP_DPCD_QUIRK_CONSTANT_N);
 	int bpp, slots = -EINVAL;
 	int ret = 0;
 
@@ -72,18 +75,20 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
 	// TODO: Handle pbn_div changes by adding a new MST helper
 	if (!mst_state->pbn_div) {
 		mst_state->pbn_div = drm_dp_get_vc_payload_bw(&intel_dp->mst_mgr,
-							      limits->max_rate,
-							      limits->max_lane_count);
+							      crtc_state->port_clock,
+							      crtc_state->lane_count);
 	}
 
-	for (bpp = limits->max_bpp; bpp >= limits->min_bpp; bpp -= 2 * 3) {
+	for (bpp = max_bpp; bpp >= min_bpp; bpp -= step) {
 		crtc_state->pipe_bpp = bpp;
 
 		crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
-						       crtc_state->pipe_bpp,
-						       false);
+						       dsc ? bpp << 4 : crtc_state->pipe_bpp,
+						       dsc);
+
 		slots = drm_dp_atomic_find_time_slots(state, &intel_dp->mst_mgr,
-						      connector->port, crtc_state->pbn);
+						      connector->port,
+						      crtc_state->pbn);
 		if (slots == -EDEADLK)
 			return slots;
 		if (slots >= 0) {
@@ -101,11 +106,32 @@ static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
 	if (ret && slots >= 0)
 		slots = ret;
 
-	if (slots < 0) {
+	if (slots < 0)
 		drm_dbg_kms(&i915->drm, "failed finding vcpi slots:%d\n",
 			    slots);
+
+	return slots;
+}
+
+
+static int intel_dp_mst_compute_link_config(struct intel_encoder *encoder,
+					    struct intel_crtc_state *crtc_state,
+					    struct drm_connector_state *conn_state,
+					    struct link_config_limits *limits)
+{
+	const struct drm_display_mode *adjusted_mode =
+		&crtc_state->hw.adjusted_mode;
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
+	struct intel_dp *intel_dp = &intel_mst->primary->dp;
+	bool constant_n = drm_dp_has_quirk(&intel_dp->desc, DP_DPCD_QUIRK_CONSTANT_N);
+	int slots = -EINVAL;
+
+	slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state, limits->max_bpp,
+						     limits->min_bpp, limits,
+						     conn_state, 2 * 3, false);
+
+	if (slots < 0)
 		return slots;
-	}
 
 	intel_link_compute_m_n(crtc_state->pipe_bpp,
 			       crtc_state->lane_count,
@@ -123,25 +149,21 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
 						struct drm_connector_state *conn_state,
 						struct link_config_limits *limits)
 {
-	struct drm_atomic_state *state = crtc_state->uapi.state;
-	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
-	struct intel_dp *intel_dp = &intel_mst->primary->dp;
 	struct intel_connector *connector =
 		to_intel_connector(conn_state->connector);
+	struct intel_dp_mst_encoder *intel_mst = enc_to_mst(encoder);
+	struct intel_dp *intel_dp = &intel_mst->primary->dp;
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 	const struct drm_display_mode *adjusted_mode =
 		&crtc_state->hw.adjusted_mode;
 	bool constant_n = drm_dp_has_quirk(&intel_dp->desc,
 					   DP_DPCD_QUIRK_CONSTANT_N);
-	int bpp, slots = -EINVAL;
+	int slots = -EINVAL;
 	int i, num_bpc;
 	u8 dsc_bpc[3] = {0};
 	int min_bpp, max_bpp;
 	u8 dsc_max_bpc;
 
-	crtc_state->lane_count = limits->max_lane_count;
-	crtc_state->port_clock = limits->max_rate;
-
 	/* Max DSC Input BPC for ICL is 10 and for TGL+ is 12 */
 	if (DISPLAY_VER(i915) >= 12)
 		dsc_max_bpc = min_t(u8, 12, conn_state->max_requested_bpc);
@@ -162,29 +184,11 @@ static int intel_dp_dsc_mst_compute_link_config(struct intel_encoder *encoder,
 	drm_dbg_kms(&i915->drm, "DSC Sink supported min bpp %d max bpp %d\n",
 		    min_bpp, max_bpp);
 
-	for (bpp = max_bpp; bpp >= min_bpp; bpp -= 2 * 3) {
-		crtc_state->pbn = drm_dp_calc_pbn_mode(adjusted_mode->crtc_clock,
-						       bpp << 4,
-						       true);
+	slots = intel_dp_mst_find_vcpi_slots_for_bpp(encoder, crtc_state, max_bpp, min_bpp,
+						     limits, conn_state, 2 * 3, true);
 
-		slots = drm_dp_atomic_find_vcpi_slots(state, &intel_dp->mst_mgr,
-						      connector->port,
-						      crtc_state->pbn, 0);
-
-		drm_dbg_kms(&i915->drm, "Trying bpp %d got %d pbn %d slots\n",
-			    bpp, crtc_state->pbn, slots);
-
-		if (slots == -EDEADLK)
-			return slots;
-		if (slots >= 0)
-			break;
-	}
-
-	if (slots < 0) {
-		drm_dbg_kms(&i915->drm, "failed finding vcpi slots:%d\n",
-			    slots);
+	if (slots < 0)
 		return slots;
-	}
 
 	intel_link_compute_m_n(crtc_state->pipe_bpp,
 			       crtc_state->lane_count,
-- 
2.24.1.485.gad05a3d8e5