drm/i915/cx0: Add intel_cx0_get_owned_lane_mask()

There are more parts of C10/C20 programming that need to take owned
lanes into account. Define the function intel_cx0_get_owned_lane_mask()
and use it. There will be new users of that function in upcoming
changes.

BSpec: 64539
Reviewed-by: Mika Kahola <mika.kahola@intel.com>
Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230814131331.69516-2-gustavo.sousa@intel.com

drivers/gpu/drm/i915/display/intel_cx0_phy.c

@@ -46,6 +46,22 @@ static int lane_mask_to_lane(u8 lane_mask)
 	return ilog2(lane_mask);
 }
 
+static u8 intel_cx0_get_owned_lane_mask(struct drm_i915_private *i915,
+					struct intel_encoder *encoder)
+{
+	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
+
+	if (!intel_tc_port_in_dp_alt_mode(dig_port))
+		return INTEL_CX0_BOTH_LANES;
+
+	/*
+	 * In DP-alt with pin assignment D, only PHY lane 0 is owned
+	 * by display and lane 1 is owned by USB.
+	 */
+	return intel_tc_port_fia_max_lane_count(dig_port) > 2
+		? INTEL_CX0_BOTH_LANES : INTEL_CX0_LANE0;
+}
+
 static void
 assert_dc_off(struct drm_i915_private *i915)
 {
@@ -2534,17 +2550,15 @@ static void intel_cx0_phy_lane_reset(struct drm_i915_private *i915,
 {
 	enum port port = encoder->port;
 	enum phy phy = intel_port_to_phy(i915, port);
-	bool both_lanes =  intel_tc_port_fia_max_lane_count(enc_to_dig_port(encoder)) > 2;
-	u8 lane_mask = lane_reversal ? INTEL_CX0_LANE1 :
-				  INTEL_CX0_LANE0;
-	u32 lane_pipe_reset = both_lanes ?
-			      XELPDP_LANE_PIPE_RESET(0) |
-			      XELPDP_LANE_PIPE_RESET(1) :
-			      XELPDP_LANE_PIPE_RESET(0);
-	u32 lane_phy_current_status = both_lanes ?
-				      XELPDP_LANE_PHY_CURRENT_STATUS(0) |
-				      XELPDP_LANE_PHY_CURRENT_STATUS(1) :
-				      XELPDP_LANE_PHY_CURRENT_STATUS(0);
+	u8 owned_lane_mask = intel_cx0_get_owned_lane_mask(i915, encoder);
+	u8 lane_mask = lane_reversal ? INTEL_CX0_LANE1 : INTEL_CX0_LANE0;
+	u32 lane_pipe_reset = owned_lane_mask == INTEL_CX0_BOTH_LANES
+				? XELPDP_LANE_PIPE_RESET(0) | XELPDP_LANE_PIPE_RESET(1)
+				: XELPDP_LANE_PIPE_RESET(0);
+	u32 lane_phy_current_status = owned_lane_mask == INTEL_CX0_BOTH_LANES
+					? (XELPDP_LANE_PHY_CURRENT_STATUS(0) |
+					   XELPDP_LANE_PHY_CURRENT_STATUS(1))
+					: XELPDP_LANE_PHY_CURRENT_STATUS(0);
 
 	if (__intel_de_wait_for_register(i915, XELPDP_PORT_BUF_CTL1(port),
 					 XELPDP_PORT_BUF_SOC_PHY_READY,
@@ -2564,15 +2578,11 @@ static void intel_cx0_phy_lane_reset(struct drm_i915_private *i915,
 			 phy_name(phy), XELPDP_PORT_RESET_START_TIMEOUT_US);
 
 	intel_de_rmw(i915, XELPDP_PORT_CLOCK_CTL(port),
-		     intel_cx0_get_pclk_refclk_request(both_lanes ?
-						       INTEL_CX0_BOTH_LANES :
-						       INTEL_CX0_LANE0),
+		     intel_cx0_get_pclk_refclk_request(owned_lane_mask),
 		     intel_cx0_get_pclk_refclk_request(lane_mask));
 
 	if (__intel_de_wait_for_register(i915, XELPDP_PORT_CLOCK_CTL(port),
-					 intel_cx0_get_pclk_refclk_ack(both_lanes ?
-								       INTEL_CX0_BOTH_LANES :
-								       INTEL_CX0_LANE0),
+					 intel_cx0_get_pclk_refclk_ack(owned_lane_mask),
 					 intel_cx0_get_pclk_refclk_ack(lane_mask),
 					 XELPDP_REFCLK_ENABLE_TIMEOUT_US, 0, NULL))
 		drm_warn(&i915->drm, "PHY %c failed to request refclk after %dus.\n",