[Intel-gfx] [PATCH 12/23] drm/i915: Sanitize the TypeC connect/detect sequences

[Imre Deak]

Make the order during detection more consistent: first reset the TypeC
port mode if needed (adding new helpers for this), then detect any
connected sink.

To check if a port mode reset is needed determine first the target port
mode based on the live status if a sink is already connected or the
PHY status complete flag otherwise.

Add a WARN in legacy mode if unexpectedly we can't set the unsafe mode
or if the FIA doesn't provide the 4 lanes required.

Cc: José Roberto de Souza <jose.souza at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/intel_tc.c | 104 +++++++++++++++-----------------
 1 file changed, 50 insertions(+), 54 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_tc.c b/drivers/gpu/drm/i915/intel_tc.c
index d91381c0e87d..9832e2ddb92e 100644
--- a/drivers/gpu/drm/i915/intel_tc.c
+++ b/drivers/gpu/drm/i915/intel_tc.c
@@ -188,43 +188,46 @@ static bool icl_tc_phy_set_safe_mode(struct intel_digital_port *dig_port,
  * will require a lot of coordination with user space and thorough testing for
  * the extra possible cases.
  */
-static bool icl_tc_phy_connect(struct intel_digital_port *dig_port)
+static void icl_tc_phy_connect(struct intel_digital_port *dig_port)
 {
 	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 live_status_mask;
-
-	if (dig_port->tc_mode != TC_PORT_LEGACY &&
-	    dig_port->tc_mode != TC_PORT_DP_ALT)
-		return true;
 
 	if (!icl_tc_phy_status_complete(dig_port)) {
 		DRM_DEBUG_KMS("Port %s: PHY not ready\n",
 			      tc_port_name(dev_priv, tc_port));
-		WARN_ON(dig_port->tc_legacy_port);
-		return false;
+		goto out_set_tbt_alt_mode;
 	}
 
-	if (!icl_tc_phy_set_safe_mode(dig_port, false))
-		return false;
+	if (!icl_tc_phy_set_safe_mode(dig_port, false) &&
+	    !WARN_ON(dig_port->tc_legacy_port))
+		goto out_set_tbt_alt_mode;
 
-	if (dig_port->tc_mode == TC_PORT_LEGACY)
-		return true;
+	if (dig_port->tc_legacy_port) {
+		WARN_ON(intel_tc_port_fia_max_lane_count(dig_port) != 4);
+		dig_port->tc_mode = TC_PORT_LEGACY;
 
-	live_status_mask = tc_port_live_status_mask(dig_port);
+		return;
+	}
 
 	/*
 	 * Now we have to re-check the live state, in case the port recently
 	 * became disconnected. Not necessary for legacy mode.
 	 */
-	if (!(live_status_mask & BIT(TC_PORT_DP_ALT))) {
+	if (!(tc_port_live_status_mask(dig_port) & BIT(TC_PORT_DP_ALT))) {
 		DRM_DEBUG_KMS("Port %s: PHY sudden disconnect\n",
 			      tc_port_name(dev_priv, tc_port));
-		icl_tc_phy_disconnect(dig_port);
-		return false;
+		goto out_set_safe_mode;
 	}
 
-	return true;
+	dig_port->tc_mode = TC_PORT_DP_ALT;
+
+	return;
+
+out_set_safe_mode:
+	icl_tc_phy_set_safe_mode(dig_port, true);
+out_set_tbt_alt_mode:
+	dig_port->tc_mode = TC_PORT_TBT_ALT;
 }
 
 /*
@@ -233,9 +236,6 @@ static bool icl_tc_phy_connect(struct intel_digital_port *dig_port)
  */
 void icl_tc_phy_disconnect(struct intel_digital_port *dig_port)
 {
-	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);
-
 	switch (dig_port->tc_mode) {
 	case TC_PORT_LEGACY:
 	case TC_PORT_DP_ALT:
@@ -248,31 +248,41 @@ void icl_tc_phy_disconnect(struct intel_digital_port *dig_port)
 	default:
 		MISSING_CASE(dig_port->tc_mode);
 	}
-
-	DRM_DEBUG_KMS("Port %s: mode %s disconnected\n",
-		      tc_port_name(dev_priv, tc_port),
-		      tc_port_mode_name(dig_port->tc_mode));
 }
 
-static void icl_update_tc_port_type(struct drm_i915_private *dev_priv,
-				    struct intel_digital_port *intel_dig_port,
-				    u32 live_status_mask)
+static enum tc_port_mode
+intel_tc_port_get_target_mode(struct intel_digital_port *dig_port)
 {
-	enum port port = intel_dig_port->base.port;
-	enum tc_port_mode old_mode = intel_dig_port->tc_mode;
+	u32 live_status_mask = tc_port_live_status_mask(dig_port);
 
-	if (!live_status_mask)
-		return;
+	if (live_status_mask)
+		return fls(live_status_mask) - 1;
+
+	return icl_tc_phy_status_complete(dig_port) &&
+	       dig_port->tc_legacy_port ? TC_PORT_LEGACY :
+					  TC_PORT_TBT_ALT;
+}
 
-	intel_dig_port->tc_mode = fls(live_status_mask) - 1;
+static void intel_tc_port_reset_mode(struct intel_digital_port *dig_port)
+{
+	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);
+	enum tc_port_mode old_tc_mode = dig_port->tc_mode;
 
-	if (old_mode != intel_dig_port->tc_mode)
-		DRM_DEBUG_KMS("Port %s: port has mode %s\n",
-			      tc_port_name(dev_priv,
-					   intel_port_to_tc(dev_priv, port)),
-			      tc_port_mode_name(intel_dig_port->tc_mode));
+	icl_tc_phy_disconnect(dig_port);
+	icl_tc_phy_connect(dig_port);
+
+	DRM_DEBUG_KMS("Port %s: TC port mode reset (%s -> %s)\n",
+		      tc_port_name(dev_priv, tc_port),
+		      tc_port_mode_name(old_tc_mode),
+		      tc_port_mode_name(dig_port->tc_mode));
 }
 
+static bool
+intel_tc_port_needs_reset(struct intel_digital_port *dig_port)
+{
+	return intel_tc_port_get_target_mode(dig_port) != dig_port->tc_mode;
+}
 
 /*
  * The type-C ports are different because even when they are connected, they may
@@ -286,23 +296,9 @@ static void icl_update_tc_port_type(struct drm_i915_private *dev_priv,
  */
 bool intel_tc_port_connected(struct intel_digital_port *dig_port)
 {
-	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
-	u32 live_status_mask = tc_port_live_status_mask(dig_port);
+	if (intel_tc_port_needs_reset(dig_port))
+		intel_tc_port_reset_mode(dig_port);
 
-	/*
-	 * The spec says we shouldn't be using the ISR bits for detecting
-	 * between TC and TBT. We should use DFLEXDPSP.
-	 */
-	if (!live_status_mask && !dig_port->tc_legacy_port) {
-		icl_tc_phy_disconnect(dig_port);
-
-		return false;
-	}
-
-	icl_update_tc_port_type(dev_priv, dig_port, live_status_mask);
-	if (!icl_tc_phy_connect(dig_port))
-		return false;
-
-	return true;
+	return tc_port_live_status_mask(dig_port) & BIT(dig_port->tc_mode);
 }
 
-- 
2.17.1