[Intel-gfx] [PATCH 3/5] drm/i915/icl: Update FIA supported lane count for hpd.

[Paulo Zanoni]

From: Animesh Manna <animesh.manna at intel.com>

In ICL, Flexible IO Adapter (FIA) muxes data and clocks of USB 3.1,
tbt and display controller. In DP alt mode FIA configure the
number of lanes and will be used apart from DPCD read to calculate max
available lanes for DP enablement.

v2 (from Paulo): Simple rebase.

Reviewed-by: Anusha Srivatsa <anusha.srivatsa at intel.com> (v1).
Signed-off-by: Animesh Manna <animesh.manna at intel.com>
[Paulo: significant rewrite of the patch.]
Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/i915_reg.h |  3 +++
 drivers/gpu/drm/i915/intel_dp.c | 33 ++++++++++++++++++++++++++++++++-
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 93de6f724e77..72acecaad5c1 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -10705,5 +10705,8 @@ enum skl_power_gate {
 #define PORT_TX_DFLEXDPSP			_MMIO(0x1638A0)
 #define   TC_LIVE_STATE_TBT(tc_port)		(1 << ((tc_port) * 8 + 6))
 #define   TC_LIVE_STATE_TC(tc_port)		(1 << ((tc_port) * 8 + 5))
+#define   DP_LANE_ASSIGNMENT_SHIFT(tc_port)	((tc_port) * 8)
+#define   DP_LANE_ASSIGNMENT_MASK(tc_port)	(0xf << ((tc_port) * 8))
+#define   DP_LANE_ASSIGNMENT(tc_port, x)	((x) << ((tc_port) * 8))
 
 #endif /* _I915_REG_H_ */
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 90c5ba6b222b..bb59e71d6f9c 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -176,14 +176,45 @@ static int intel_dp_max_common_rate(struct intel_dp *intel_dp)
 	return intel_dp->common_rates[intel_dp->num_common_rates - 1];
 }
 
+static int intel_dp_get_fia_supported_lane_count(struct intel_dp *intel_dp)
+{
+	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
+	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
+	enum tc_port tc_port = intel_port_to_tc(dev_priv, dig_port->base.port);
+	u32 lane_info;
+
+	if (tc_port == PORT_TC_NONE || dig_port->tc_type != TC_PORT_TYPEC)
+		return 4;
+
+	lane_info = (I915_READ(PORT_TX_DFLEXDPSP) &
+		     DP_LANE_ASSIGNMENT_MASK(tc_port)) >>
+		    DP_LANE_ASSIGNMENT_SHIFT(tc_port);
+
+	switch (lane_info) {
+	default:
+		MISSING_CASE(lane_info);
+	case 1:
+	case 2:
+	case 4:
+	case 8:
+		return 1;
+	case 3:
+	case 12:
+		return 2;
+	case 15:
+		return 4;
+	}
+}
+
 /* Theoretical max between source and sink */
 static int intel_dp_max_common_lane_count(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
 	int source_max = intel_dig_port->max_lanes;
 	int sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
+	int fia_max = intel_dp_get_fia_supported_lane_count(intel_dp);
 
-	return min(source_max, sink_max);
+	return min3(source_max, sink_max, fia_max);
 }
 
 int intel_dp_max_lane_count(struct intel_dp *intel_dp)
-- 
2.17.1