[PATCH 4/5] drm/i915/display: Implement Wa_14021768792 for BMG DP for link_m/n ratio > 10

[Ankit Nautiyal]

Handle the bypass logic for the M/N ratio limit for DP.
Calculate the M/N ratio, check if it can bypass the limit, and set the
appropriate flags for the workaround.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c |  1 -
 drivers/gpu/drm/i915/display/intel_display.h |  4 +++
 drivers/gpu/drm/i915/display/intel_dp.c      | 31 ++++++++++++++++++--
 drivers/gpu/drm/i915/display/intel_dp.h      |  4 +++
 drivers/gpu/drm/i915/display/intel_dp_mst.c  |  5 +++-
 5 files changed, 41 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index cd564f900507..d3cd7281c68e 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -3427,7 +3427,6 @@ void bmg_bypass_m_n_limit_read(struct intel_crtc *crtc,
 		m_n->bypass_m_n_ratio_limit = true;
 }
 
-static
 int bmg_can_bypass_m_n_limit(struct drm_i915_private *i915,
 			     int m_n_ratio,
 			     enum pipe pipe)
diff --git a/drivers/gpu/drm/i915/display/intel_display.h b/drivers/gpu/drm/i915/display/intel_display.h
index c6ebebbcc60e..8cb9c4527a9d 100644
--- a/drivers/gpu/drm/i915/display/intel_display.h
+++ b/drivers/gpu/drm/i915/display/intel_display.h
@@ -585,4 +585,8 @@ bool assert_port_valid(struct drm_i915_private *i915, enum port port);
 
 bool intel_scanout_needs_vtd_wa(struct drm_i915_private *i915);
 
+int bmg_can_bypass_m_n_limit(struct drm_i915_private *i915,
+			     int m_n_ratio,
+			     enum pipe pipe);
+
 #endif
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 2ccdc34526ca..879e7839076f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2740,6 +2740,27 @@ static bool can_enable_drrs(struct intel_connector *connector,
 		intel_panel_drrs_type(connector) == DRRS_TYPE_SEAMLESS;
 }
 
+bool
+intel_dp_bmg_bypass_m_n_limit(struct drm_i915_private *i915,
+			      struct intel_link_m_n *m_n,
+			      enum pipe pipe)
+{
+	int m_n_ratio, m_n_frac;
+
+	m_n_ratio = DIV_ROUND_UP(m_n->link_m, m_n->link_n);
+
+	if (!bmg_can_bypass_m_n_limit(i915, m_n_ratio, pipe))
+		return false;
+
+	m_n_frac = m_n->link_m % m_n->link_n;
+
+	m_n->link_n_ext = m_n_ratio | (m_n_ratio + (m_n_frac  > 0 ? 1 : 0)) << 4;
+
+	m_n->bypass_m_n_ratio_limit = true;
+
+	return true;
+}
+
 static int
 intel_dp_drrs_compute_config(struct intel_connector *connector,
 			     struct intel_crtc_state *pipe_config,
@@ -2748,6 +2769,8 @@ intel_dp_drrs_compute_config(struct intel_connector *connector,
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 	const struct drm_display_mode *downclock_mode =
 		intel_panel_downclock_mode(connector, &pipe_config->hw.adjusted_mode);
+	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
+	enum pipe pipe = crtc->pipe;
 	int pixel_clock;
 	int ret;
 
@@ -2777,7 +2800,8 @@ intel_dp_drrs_compute_config(struct intel_connector *connector,
 				     pipe_config->port_clock,
 				     intel_dp_bw_fec_overhead(pipe_config->fec_enable),
 				     &pipe_config->dp_m2_n2);
-	if (ret)
+
+	if (ret && !intel_dp_bmg_bypass_m_n_limit(i915, &pipe_config->dp_m2_n2, pipe))
 		return ret;
 
 	/* FIXME: abstract this better */
@@ -2907,6 +2931,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
 	const struct drm_display_mode *fixed_mode;
 	struct intel_connector *connector = intel_dp->attached_connector;
+	struct intel_crtc *crtc = to_intel_crtc(pipe_config->uapi.crtc);
+	enum pipe pipe = crtc->pipe;
 	int ret = 0, link_bpp_x16;
 
 	if (HAS_PCH_SPLIT(dev_priv) && !HAS_DDI(dev_priv) && encoder->port != PORT_A)
@@ -2989,7 +3015,8 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 				     pipe_config->port_clock,
 				     intel_dp_bw_fec_overhead(pipe_config->fec_enable),
 				     &pipe_config->dp_m_n);
-	if (ret)
+
+	if (ret && !intel_dp_bmg_bypass_m_n_limit(dev_priv, &pipe_config->dp_m_n, pipe))
 		return ret;
 
 	/* FIXME: abstract this better */
diff --git a/drivers/gpu/drm/i915/display/intel_dp.h b/drivers/gpu/drm/i915/display/intel_dp.h
index 9be539edf817..3b144b810e62 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.h
+++ b/drivers/gpu/drm/i915/display/intel_dp.h
@@ -22,6 +22,7 @@ struct intel_crtc_state;
 struct intel_digital_port;
 struct intel_dp;
 struct intel_encoder;
+struct intel_link_m_n;
 
 struct link_config_limits {
 	int min_rate, max_rate;
@@ -201,5 +202,8 @@ intel_dp_compute_config_link_bpp_limits(struct intel_dp *intel_dp,
 
 void intel_dp_get_dsc_sink_cap(u8 dpcd_rev, struct intel_connector *connector);
 bool intel_dp_has_gamut_metadata_dip(struct intel_encoder *encoder);
+bool intel_dp_bmg_bypass_m_n_limit(struct drm_i915_private *i915,
+				   struct intel_link_m_n *m_n,
+				   enum pipe pipe);
 
 #endif /* __INTEL_DP_H__ */
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 9a285c8a1fb7..89bd3f9023d4 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -130,6 +130,8 @@ static int intel_dp_mst_compute_m_n(const struct intel_crtc_state *crtc_state,
 	const struct drm_display_mode *adjusted_mode =
 		&crtc_state->hw.adjusted_mode;
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	enum pipe pipe = crtc->pipe;
 	int ret;
 
 	/* TODO: Check WA 14013163432 to set data M/N for full BW utilization. */
@@ -137,7 +139,8 @@ static int intel_dp_mst_compute_m_n(const struct intel_crtc_state *crtc_state,
 				     adjusted_mode->crtc_clock,
 				     crtc_state->port_clock,
 				     overhead, m_n);
-	if (ret)
+
+	if (ret && !intel_dp_bmg_bypass_m_n_limit(i915, m_n, pipe))
 		return ret;
 
 	m_n->tu = DIV_ROUND_UP_ULL(mul_u32_u32(m_n->data_m, 64), m_n->data_n);
-- 
2.45.2