[PATCH v2 2/2] drm/display/dsc: MST DSC Interface Change

[Fangzhi Zuo <Jerry.Zuo@amd.com>]

[why]
Starting from dp2 where dsc passthrough is introduced, it is required to identify
the dsc passthrough aux, apart from dsc decompression aux. Existing drm_dp_mst_port function
that returns dsc_aux alone is not sufficient.

[how]
1. Interface change in drm_dp_mst_dsc_aux_for_port, and dependency changes for each vendor.
2. Rename passthrough_aux with dsc_passthrough_aux to align with the name of dsc_aux.

Signed-off-by: Fangzhi Zuo <Jerry.Zuo@amd.com>
Signed-off-by: Wayne Lin <wayne.lin@amd.com>
---
 .../amd/display/amdgpu_dm/amdgpu_dm_debugfs.c |  2 +-
 .../amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 20 +++++------
 .../display/amdgpu_dm/amdgpu_dm_mst_types.c   | 30 ++++++++--------
 drivers/gpu/drm/display/drm_dp_mst_topology.c | 34 +++++++++----------
 drivers/gpu/drm/i915/display/intel_dp.c       |  2 +-
 drivers/gpu/drm/i915/display/intel_dp_mst.c   |  3 +-
 include/drm/display/drm_dp_mst_helper.h       |  6 ++--
 7 files changed, 48 insertions(+), 49 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
index db56b0aa5454..0da703f4ccac 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_debugfs.c
@@ -1370,7 +1370,7 @@ static int dp_dsc_fec_support_show(struct seq_file *m, void *data)
 			 * enable DSC on the sink device or on MST branch
 			 * its connected to.
 			 */
-			if (aconnector->dsc_aux) {
+			if (aconnector->mst_output_port->dsc_aux) {
 				is_fec_supported = true;
 				is_dsc_supported = true;
 			}
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
index 069e0195e50a..2e5e490f9027 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -810,20 +810,20 @@ bool dm_helpers_dp_write_dsc_enable(
 	uint8_t ret = 0;
 
 	if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
-		if (!aconnector->dsc_aux)
+		if (!aconnector->mst_output_port->dsc_aux)
 			return false;
 
 		// apply w/a to synaptics
 		if (needs_dsc_aux_workaround(aconnector->dc_link) &&
 		    (aconnector->mst_downstream_port_present.byte & 0x7) != 0x3)
 			return write_dsc_enable_synaptics_non_virtual_dpcd_mst(
-				aconnector->dsc_aux, stream, enable_dsc);
+				aconnector->mst_output_port->dsc_aux, stream, enable_dsc);
 
 		port = aconnector->mst_output_port;
 
 		if (enable) {
-			if (port->passthrough_aux) {
-				ret = drm_dp_dpcd_write(port->passthrough_aux,
+			if (port->dsc_passthrough_aux) {
+				ret = drm_dp_dpcd_write(port->dsc_passthrough_aux,
 							DP_DSC_ENABLE,
 							&enable_passthrough, 1);
 				drm_dbg_dp(dev,
@@ -831,24 +831,24 @@ bool dm_helpers_dp_write_dsc_enable(
 					   ret);
 			}
 
-			ret = drm_dp_dpcd_write(aconnector->dsc_aux,
+			ret = drm_dp_dpcd_write(aconnector->mst_output_port->dsc_aux,
 						DP_DSC_ENABLE, &enable_dsc, 1);
 			drm_dbg_dp(dev,
 				   "MST_DSC Sent DSC decoding enable to %s port, ret = %u\n",
-				   (port->passthrough_aux) ? "remote RX" :
+				   (port->dsc_passthrough_aux) ? "remote RX" :
 				   "virtual dpcd",
 				   ret);
 		} else {
-			ret = drm_dp_dpcd_write(aconnector->dsc_aux,
+			ret = drm_dp_dpcd_write(aconnector->mst_output_port->dsc_aux,
 						DP_DSC_ENABLE, &enable_dsc, 1);
 			drm_dbg_dp(dev,
 				   "MST_DSC Sent DSC decoding disable to %s port, ret = %u\n",
-				   (port->passthrough_aux) ? "remote RX" :
+				   (port->dsc_passthrough_aux) ? "remote RX" :
 				   "virtual dpcd",
 				   ret);
 
-			if (port->passthrough_aux) {
-				ret = drm_dp_dpcd_write(port->passthrough_aux,
+			if (port->dsc_passthrough_aux) {
+				ret = drm_dp_dpcd_write(port->dsc_passthrough_aux,
 							DP_DSC_ENABLE,
 							&enable_passthrough, 1);
 				drm_dbg_dp(dev,
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
index a08e8a0b696c..5d2653e1a5f6 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
@@ -183,8 +183,8 @@ amdgpu_dm_mst_connector_early_unregister(struct drm_connector *connector)
 		dc_sink_release(dc_sink);
 		aconnector->dc_sink = NULL;
 		aconnector->edid = NULL;
-		aconnector->dsc_aux = NULL;
-		port->passthrough_aux = NULL;
+		aconnector->mst_output_port->dsc_aux = NULL;
+		aconnector->mst_output_port->dsc_passthrough_aux = NULL;
 	}
 
 	aconnector->mst_status = MST_STATUS_DEFAULT;
@@ -237,7 +237,7 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto
 	u8 dsc_branch_dec_caps_raw[3] = { 0 };	// DSC branch decoder caps 0xA0 ~ 0xA2
 	u8 *dsc_branch_dec_caps = NULL;
 
-	aconnector->dsc_aux = drm_dp_mst_dsc_aux_for_port(port);
+	drm_dp_mst_dsc_aux_for_port(port);
 
 	/*
 	 * drm_dp_mst_dsc_aux_for_port() will return NULL for certain configs
@@ -250,19 +250,19 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto
 	 */
 	if (!aconnector->dsc_aux && !port->parent->port_parent &&
 	    needs_dsc_aux_workaround(aconnector->dc_link))
-		aconnector->dsc_aux = &aconnector->mst_root->dm_dp_aux.aux;
+		aconnector->mst_output_port->dsc_aux = &aconnector->mst_root->dm_dp_aux.aux;
 
 	/* synaptics cascaded MST hub case */
 	if (is_synaptics_cascaded_panamera(aconnector->dc_link, port))
-		aconnector->dsc_aux = port->mgr->aux;
+		aconnector->mst_output_port->dsc_aux = port->mgr->aux;
 
-	if (!aconnector->dsc_aux)
+	if (!aconnector->mst_output_port->dsc_aux)
 		return false;
 
-	if (drm_dp_dpcd_read(aconnector->dsc_aux, DP_DSC_SUPPORT, dsc_caps, 16) < 0)
+	if (drm_dp_dpcd_read(aconnector->mst_output_port->dsc_aux, DP_DSC_SUPPORT, dsc_caps, 16) < 0)
 		return false;
 
-	if (drm_dp_dpcd_read(aconnector->dsc_aux,
+	if (drm_dp_dpcd_read(aconnector->mst_output_port->dsc_aux,
 			DP_DSC_BRANCH_OVERALL_THROUGHPUT_0, dsc_branch_dec_caps_raw, 3) == 3)
 		dsc_branch_dec_caps = dsc_branch_dec_caps_raw;
 
@@ -279,10 +279,10 @@ static bool retrieve_downstream_port_device(struct amdgpu_dm_connector *aconnect
 {
 	union dp_downstream_port_present ds_port_present;
 
-	if (!aconnector->dsc_aux)
+	if (!aconnector->mst_output_port->dsc_aux)
 		return false;
 
-	if (drm_dp_dpcd_read(aconnector->dsc_aux, DP_DOWNSTREAMPORT_PRESENT, &ds_port_present, 1) < 0) {
+	if (drm_dp_dpcd_read(aconnector->mst_output_port->dsc_aux, DP_DOWNSTREAMPORT_PRESENT, &ds_port_present, 1) < 0) {
 		DRM_INFO("Failed to read downstream_port_present 0x05 from DFP of branch device\n");
 		return false;
 	}
@@ -501,8 +501,8 @@ dm_dp_mst_detect(struct drm_connector *connector,
 		dc_sink_release(aconnector->dc_sink);
 		aconnector->dc_sink = NULL;
 		aconnector->edid = NULL;
-		aconnector->dsc_aux = NULL;
-		port->passthrough_aux = NULL;
+		aconnector->mst_output_port->dsc_aux = NULL;
+		aconnector->mst_output_port->dsc_passthrough_aux = NULL;
 
 		amdgpu_dm_set_mst_status(&aconnector->mst_status,
 			MST_REMOTE_EDID | MST_ALLOCATE_NEW_PAYLOAD | MST_CLEAR_ALLOCATED_PAYLOAD,
@@ -1302,7 +1302,7 @@ static bool is_dsc_need_re_compute(
 			continue;
 
 		aconnector = (struct amdgpu_dm_connector *) stream->dm_stream_context;
-		if (!aconnector || !aconnector->dsc_aux)
+		if (!aconnector || !aconnector->mst_output_port->dsc_aux)
 			continue;
 
 		stream_on_link[new_stream_on_link_num] = aconnector;
@@ -1787,13 +1787,13 @@ enum dc_status dm_dp_mst_is_port_support_mode(
 	}
 
 	/*DSC necessary case*/
-	if (!aconnector->dsc_aux)
+	if (!aconnector->mst_output_port->dsc_aux)
 		return DC_FAIL_BANDWIDTH_VALIDATE;
 
 	if (is_dsc_common_config_possible(stream, &bw_range)) {
 
 		/*capable of dsc passthough. dsc bitstream along the entire path*/
-		if (aconnector->mst_output_port->passthrough_aux) {
+		if (aconnector->mst_output_port->dsc_passthrough_aux) {
 			if (bw_range.min_kbps > end_to_end_bw_in_kbps) {
 				DRM_DEBUG_DRIVER("MST_DSC dsc passthrough and decode at endpoint"
 						 "Max dsc compression bw can't fit into end-to-end bw\n");
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index a4551c17a07f..483b623961e7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -2259,7 +2259,7 @@ void drm_dp_mst_connector_early_unregister(struct drm_connector *connector,
 		    port->aux.name, connector->kdev->kobj.name);
 	drm_dp_aux_unregister_devnode(&port->aux);
 	port->dsc_aux = NULL;
-	port->passthrough_aux = NULL;
+	port->dsc_passthrough_aux = NULL;
 }
 EXPORT_SYMBOL(drm_dp_mst_connector_early_unregister);
 
@@ -5447,7 +5447,8 @@ int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm
 		if (!crtc)
 			continue;
 
-		if (!drm_dp_mst_dsc_aux_for_port(pos->port))
+		drm_dp_mst_dsc_aux_for_port(pos->port);
+		if (!pos->port->dsc_aux)
 			continue;
 
 		crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
@@ -6019,16 +6020,13 @@ EXPORT_SYMBOL(drm_dp_mst_aux_for_parent);
  * Depending on the situation, DSC may be enabled via the endpoint aux,
  * the immediately upstream aux, or the connector's physical aux.
  *
- * This is both the correct aux to read DSC_CAPABILITY and the
- * correct aux to write DSC_ENABLED.
- *
- * This operation can be expensive (up to four aux reads), so
- * the caller should cache the return.
- *
  * Returns:
- * NULL if DSC cannot be enabled on this port, otherwise the aux device
+ * port->dsc_aux - point for dsc decompression
+ *   null if dsc decompression point not found
+ * port->dsc_passthrough_aux - point for dsc passthrough
+ *   null no dsc passthrough support found
  */
-struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
+void drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
 {
 	struct drm_dp_mst_topology_mgr *mgr = port->mgr;
 	struct drm_dp_mst_port *immediate_upstream_port = NULL;
@@ -6041,17 +6039,17 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
 	u8 fec_cap;
 
 	if (!port)
-		return NULL;
+		return;
 
 	port->dsc_aux = NULL;
-	port->passthrough_aux = NULL;
+	port->dsc_passthrough_aux = NULL;
 
 	/* Policy start */
 	if (!drm_dp_mst_is_end_device(port->pdt, port->mcs)) {
 		drm_err(mgr->dev,
 			"MST_DSC Can't determine dsc aux for port %p which is not connected to end device\n",
 			port);
-		return NULL;
+		return;
 	}
 
 	if (port->parent->port_parent)
@@ -6079,12 +6077,12 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
 		goto out_dsc_fail;
 	}
 
-	/* Consider passthrough as the first option for dsc_aux/passthrough_aux */
+	/* Consider passthrough as the first option for dsc_aux/dsc_passthrough_aux */
 	if (endpoint_dsc & DP_DSC_DECOMPRESSION_IS_SUPPORTED &&
 			upstream_dsc & DP_DSC_PASSTHROUGH_IS_SUPPORTED) {
 		dsc_port = port;
 		port->dsc_aux = &port->aux;
-		port->passthrough_aux = upstream_aux;
+		port->dsc_passthrough_aux = upstream_aux;
 		drm_info(mgr->dev, "MST_DSC dsc passthrough to endpoint\n");
 	}
 
@@ -6147,11 +6145,11 @@ struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port)
 		goto out_dsc_fail;
 	}
 
-	return port->dsc_aux;
+	return;
 
 out_dsc_fail:
 	port->dsc_aux = NULL;
-	port->passthrough_aux = NULL;
-	return NULL;
+	port->dsc_passthrough_aux = NULL;
+	return;
 }
 EXPORT_SYMBOL(drm_dp_mst_dsc_aux_for_port);
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 90fa73575feb..4520456a6680 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -3228,7 +3228,7 @@ intel_dp_sink_set_dsc_passthrough(const struct intel_connector *connector,
 {
 	struct drm_i915_private *i915 = to_i915(connector->base.dev);
 	struct drm_dp_aux *aux = connector->port ?
-				 connector->port->passthrough_aux : NULL;
+				 connector->port->dsc_passthrough_aux : NULL;
 
 	if (!aux)
 		return;
diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 15541932b809..73cb1c673525 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -1699,7 +1699,8 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
 
 	intel_dp_init_modeset_retry_work(intel_connector);
 
-	intel_connector->dp.dsc_decompression_aux = drm_dp_mst_dsc_aux_for_port(port);
+	drm_dp_mst_dsc_aux_for_port(port);
+	intel_connector->dp.dsc_decompression_aux = port->dsc_aux;
 	intel_dp_mst_read_decompression_port_dsc_caps(intel_dp, intel_connector);
 	intel_connector->dp.dsc_hblank_expansion_quirk =
 		detect_dsc_hblank_expansion_quirk(intel_connector);
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index 672e8f6b5655..630ecf872e68 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -82,7 +82,7 @@ struct drm_dp_mst_branch;
  * by &drm_dp_mst_topology_mgr.base.lock.
  * @dsc_aux: aux to which DSC decompression request should be sent,
  * only set if DSC decompression is possible.
- * @passthrough_aux: parent aux to which DSC pass-through requests should be
+ * @dsc_passthrough_aux: parent aux to which DSC pass-through requests should be
  * sent, only set if DSC pass-through is possible.
  * @parent: branch device parent of this port
  * @connector: DRM connector this port is connected to. Protected by
@@ -138,7 +138,7 @@ struct drm_dp_mst_port {
 	struct drm_dp_mst_branch *mstb;
 	struct drm_dp_aux aux; /* i2c bus for this port? */
 	struct drm_dp_aux *dsc_aux;
-	struct drm_dp_aux *passthrough_aux;
+	struct drm_dp_aux *dsc_passthrough_aux;
 	struct drm_dp_mst_branch *parent;
 
 	struct drm_connector *connector;
@@ -959,7 +959,7 @@ bool drm_dp_mst_port_is_logical(struct drm_dp_mst_port *port)
 }
 
 struct drm_dp_aux *drm_dp_mst_aux_for_parent(struct drm_dp_mst_port *port);
-struct drm_dp_aux *drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port);
+void drm_dp_mst_dsc_aux_for_port(struct drm_dp_mst_port *port);
 
 static inline struct drm_dp_mst_topology_state *
 to_drm_dp_mst_topology_state(struct drm_private_state *state)
-- 
2.43.0