drm/amd/display: Add MST atomic routines

- Adding encoder atomic check to find vcpi slots for a connector
- Using DRM helper functions to calculate PBN
- Adding connector atomic check to release vcpi slots if connector
loses CRTC
- Calculate  PBN and VCPI slots only once during atomic
check and store them on crtc_state to eliminate
redundant calculation
- Call drm_dp_mst_atomic_check to verify validity of MST topology
during state atomic check

v2: squashed previous 3 separate patches, removed DSC PBN calculation,
and added PBN and VCPI slots properties to amdgpu connector

v3:
- moved vcpi_slots and pbn properties to dm_crtc_state and dc_stream_state
- updates stream's vcpi_slots and pbn on commit
- separated patch from the DSC MST series

v4:
- set vcpi_slots and pbn properties to dm_connector_state
- copy porperties from connector state on to crtc state

v5:
- keep the pbn and vcpi values only on connnector state
- added a void pointer to the stream state instead on two ints,
because dc_stream_state is OS agnostic. Pointer points to the
current dm_connector_state.

v6:
- Remove new param from stream

v7:
- Fix error with using max capable bpc

v8:
- squash in fix from Gustavo A. R. Silva

Reviewed-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -4095,7 +4095,8 @@ void amdgpu_dm_connector_funcs_reset(struct drm_connector *connector)
 		state->underscan_hborder = 0;
 		state->underscan_vborder = 0;
 		state->base.max_requested_bpc = 8;
-
+		state->vcpi_slots = 0;
+		state->pbn = 0;
 		if (connector->connector_type == DRM_MODE_CONNECTOR_eDP)
 			state->abm_level = amdgpu_dm_abm_level;
 
@@ -4123,7 +4124,8 @@ amdgpu_dm_connector_atomic_duplicate_state(struct drm_connector *connector)
 	new_state->underscan_enable = state->underscan_enable;
 	new_state->underscan_hborder = state->underscan_hborder;
 	new_state->underscan_vborder = state->underscan_vborder;
-
+	new_state->vcpi_slots = state->vcpi_slots;
+	new_state->pbn = state->pbn;
 	return &new_state->base;
 }
 
@@ -4520,10 +4522,64 @@ static void dm_encoder_helper_disable(struct drm_encoder *encoder)
 
 }
 
+static int convert_dc_color_depth_into_bpc (enum dc_color_depth display_color_depth)
+{
+	switch (display_color_depth) {
+		case COLOR_DEPTH_666:
+			return 6;
+		case COLOR_DEPTH_888:
+			return 8;
+		case COLOR_DEPTH_101010:
+			return 10;
+		case COLOR_DEPTH_121212:
+			return 12;
+		case COLOR_DEPTH_141414:
+			return 14;
+		case COLOR_DEPTH_161616:
+			return 16;
+		default:
+			break;
+		}
+	return 0;
+}
+
 static int dm_encoder_helper_atomic_check(struct drm_encoder *encoder,
 					  struct drm_crtc_state *crtc_state,
 					  struct drm_connector_state *conn_state)
 {
+	struct drm_atomic_state *state = crtc_state->state;
+	struct drm_connector *connector = conn_state->connector;
+	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
+	struct dm_connector_state *dm_new_connector_state = to_dm_connector_state(conn_state);
+	const struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
+	struct drm_dp_mst_topology_mgr *mst_mgr;
+	struct drm_dp_mst_port *mst_port;
+	enum dc_color_depth color_depth;
+	int clock, bpp = 0;
+
+	if (!aconnector->port || !aconnector->dc_sink)
+		return 0;
+
+	mst_port = aconnector->port;
+	mst_mgr = &aconnector->mst_port->mst_mgr;
+
+	if (!crtc_state->connectors_changed && !crtc_state->mode_changed)
+		return 0;
+
+	if (!state->duplicated) {
+		color_depth = convert_color_depth_from_display_info(connector, conn_state);
+		bpp = convert_dc_color_depth_into_bpc(color_depth) * 3;
+		clock = adjusted_mode->clock;
+		dm_new_connector_state->pbn = drm_dp_calc_pbn_mode(clock, bpp);
+	}
+	dm_new_connector_state->vcpi_slots = drm_dp_atomic_find_vcpi_slots(state,
+									   mst_mgr,
+									   mst_port,
+									   dm_new_connector_state->pbn);
+	if (dm_new_connector_state->vcpi_slots < 0) {
+		DRM_DEBUG_ATOMIC("failed finding vcpi slots: %d\n", (int)dm_new_connector_state->vcpi_slots);
+		return dm_new_connector_state->vcpi_slots;
+	}
 	return 0;
 }
 
@@ -7566,6 +7622,11 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 	if (ret)
 		goto fail;
 
+	/* Perform validation of MST topology in the state*/
+	ret = drm_dp_mst_atomic_check(state);
+	if (ret)
+		goto fail;
+
 	if (state->legacy_cursor_update) {
 		/*
 		 * This is a fast cursor update coming from the plane update

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h

@@ -359,6 +359,8 @@ struct dm_connector_state {
 	bool underscan_enable;
 	bool freesync_capable;
 	uint8_t abm_level;
+	int vcpi_slots;
+	uint64_t pbn;
 };
 
 #define to_dm_connector_state(x)\

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c

@@ -182,15 +182,19 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
 		bool enable)
 {
 	struct amdgpu_dm_connector *aconnector;
+	struct dm_connector_state *dm_conn_state;
 	struct drm_dp_mst_topology_mgr *mst_mgr;
 	struct drm_dp_mst_port *mst_port;
-	int slots = 0;
 	bool ret;
-	int clock;
-	int bpp = 0;
-	int pbn = 0;
 
 	aconnector = (struct amdgpu_dm_connector *)stream->dm_stream_context;
+	/* Accessing the connector state is required for vcpi_slots allocation
+	 * and directly relies on behaviour in commit check
+	 * that blocks before commit guaranteeing that the state
+	 * is not gonna be swapped while still in use in commit tail */
+
+	dm_conn_state = to_dm_connector_state(aconnector->base.state);
+
 
 	if (!aconnector || !aconnector->mst_port)
 		return false;
@@ -203,42 +207,10 @@ bool dm_helpers_dp_mst_write_payload_allocation_table(
 	mst_port = aconnector->port;
 
 	if (enable) {
-		clock = stream->timing.pix_clk_100hz / 10;
-
-		switch (stream->timing.display_color_depth) {
-
-		case COLOR_DEPTH_666:
-			bpp = 6;
-			break;
-		case COLOR_DEPTH_888:
-			bpp = 8;
-			break;
-		case COLOR_DEPTH_101010:
-			bpp = 10;
-			break;
-		case COLOR_DEPTH_121212:
-			bpp = 12;
-			break;
-		case COLOR_DEPTH_141414:
-			bpp = 14;
-			break;
-		case COLOR_DEPTH_161616:
-			bpp = 16;
-			break;
-		default:
-			ASSERT(bpp != 0);
-			break;
-		}
-
-		bpp = bpp * 3;
-
-		/* TODO need to know link rate */
-
-		pbn = drm_dp_calc_pbn_mode(clock, bpp);
-
-		slots = drm_dp_find_vcpi_slots(mst_mgr, pbn);
-		ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port, pbn, slots);
 
+		ret = drm_dp_mst_allocate_vcpi(mst_mgr, mst_port,
+					       dm_conn_state->pbn,
+					       dm_conn_state->vcpi_slots);
 		if (!ret)
 			return false;
 

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c

@@ -246,11 +246,43 @@ dm_dp_mst_detect(struct drm_connector *connector,
 				      aconnector->port);
 }
 
+static int dm_dp_mst_atomic_check(struct drm_connector *connector,
+				struct drm_atomic_state *state)
+{
+	struct drm_connector_state *new_conn_state =
+			drm_atomic_get_new_connector_state(state, connector);
+	struct drm_connector_state *old_conn_state =
+			drm_atomic_get_old_connector_state(state, connector);
+	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
+	struct drm_crtc_state *new_crtc_state;
+	struct drm_dp_mst_topology_mgr *mst_mgr;
+	struct drm_dp_mst_port *mst_port;
+
+	mst_port = aconnector->port;
+	mst_mgr = &aconnector->mst_port->mst_mgr;
+
+	if (!old_conn_state->crtc)
+		return 0;
+
+	if (new_conn_state->crtc) {
+		new_crtc_state = drm_atomic_get_old_crtc_state(state, new_conn_state->crtc);
+		if (!new_crtc_state ||
+		    !drm_atomic_crtc_needs_modeset(new_crtc_state) ||
+		    new_crtc_state->enable)
+			return 0;
+		}
+
+	return drm_dp_atomic_release_vcpi_slots(state,
+						mst_mgr,
+						mst_port);
+}
+
 static const struct drm_connector_helper_funcs dm_dp_mst_connector_helper_funcs = {
 	.get_modes = dm_dp_mst_get_modes,
 	.mode_valid = amdgpu_dm_connector_mode_valid,
 	.atomic_best_encoder = dm_mst_atomic_best_encoder,
 	.detect_ctx = dm_dp_mst_detect,
+	.atomic_check = dm_dp_mst_atomic_check,
 };
 
 static void amdgpu_dm_encoder_destroy(struct drm_encoder *encoder)