drm/amd/display: Add usb4_bw_alloc_support flag

[Why]
dc should have a flag for DM to enable usb4_bw_alloc in dptx

[How]
- Add usb4_bw_alloc_support flag in dc_config
Reviewed-by: Wayne Lin <wayne.lin@amd.com>
Reviewed-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Acked-by: Roman Li <roman.li@amd.com>
Signed-off-by: Peichen Huang <peichen.huang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -435,6 +435,7 @@ struct dc_config {
 	bool enable_auto_dpm_test_logs;
 	unsigned int disable_ips;
 	unsigned int disable_ips_in_vpb;
+	bool usb4_bw_alloc_support;
 };
 
 enum visual_confirm {

drivers/gpu/drm/amd/display/dc/link/link_detection.c

@@ -41,6 +41,7 @@
 #include "protocols/link_dp_dpia.h"
 #include "protocols/link_dp_phy.h"
 #include "protocols/link_dp_training.h"
+#include "protocols/link_dp_dpia_bw.h"
 #include "accessories/link_dp_trace.h"
 
 #include "link_enc_cfg.h"
@@ -991,6 +992,23 @@ static bool detect_link_and_local_sink(struct dc_link *link,
 			if (link->ep_type == DISPLAY_ENDPOINT_USB4_DPIA &&
 					link->reported_link_cap.link_rate > LINK_RATE_HIGH3)
 				link->reported_link_cap.link_rate = LINK_RATE_HIGH3;
+
+			/*
+			 * If this is DP over USB4 link then we need to:
+			 * - Enable BW ALLOC support on DPtx if applicable
+			 */
+			if (dc->config.usb4_bw_alloc_support) {
+				if (link_dp_dpia_set_dptx_usb4_bw_alloc_support(link)) {
+					/* update with non reduced link cap if bw allocation mode is supported */
+					if (link->dpia_bw_alloc_config.nrd_max_link_rate &&
+						link->dpia_bw_alloc_config.nrd_max_lane_count) {
+						link->reported_link_cap.link_rate =
+							link->dpia_bw_alloc_config.nrd_max_link_rate;
+						link->reported_link_cap.lane_count =
+							link->dpia_bw_alloc_config.nrd_max_lane_count;
+					}
+				}
+			}
 			break;
 		}
 

drivers/gpu/drm/amd/display/dc/link/link_dpms.c

@@ -2197,6 +2197,64 @@ static enum dc_status enable_link(
 
 static bool allocate_usb4_bandwidth_for_stream(struct dc_stream_state *stream, int bw)
 {
+	struct dc_link *link = stream->sink->link;
+	int req_bw = bw;
+
+	DC_LOGGER_INIT(link->ctx->logger);
+
+	if (!link->dpia_bw_alloc_config.bw_alloc_enabled)
+		return false;
+
+	if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
+		int sink_index = 0;
+		int i = 0;
+
+		for (i = 0; i < link->sink_count; i++) {
+			if (link->remote_sinks[i] == NULL)
+				continue;
+
+			if (stream->sink->sink_id != link->remote_sinks[i]->sink_id)
+				req_bw += link->dpia_bw_alloc_config.remote_sink_req_bw[i];
+			else
+				sink_index = i;
+		}
+
+		link->dpia_bw_alloc_config.remote_sink_req_bw[sink_index] = bw;
+	}
+
+	/* get dp overhead for dp tunneling */
+	link->dpia_bw_alloc_config.dp_overhead = link_dp_dpia_get_dp_overhead_in_dp_tunneling(link);
+	req_bw += link->dpia_bw_alloc_config.dp_overhead;
+
+	if (link_dp_dpia_allocate_usb4_bandwidth_for_stream(link, req_bw)) {
+		if (req_bw <= link->dpia_bw_alloc_config.allocated_bw) {
+			DC_LOG_DEBUG("%s, Success in allocate bw for link(%d), allocated_bw(%d), dp_overhead(%d)\n",
+					__func__, link->link_index, link->dpia_bw_alloc_config.allocated_bw,
+					link->dpia_bw_alloc_config.dp_overhead);
+		} else {
+			// Cannot get the required bandwidth.
+			DC_LOG_ERROR("%s, Failed to allocate bw for link(%d), allocated_bw(%d), dp_overhead(%d)\n",
+					__func__, link->link_index, link->dpia_bw_alloc_config.allocated_bw,
+					link->dpia_bw_alloc_config.dp_overhead);
+			return false;
+		}
+	} else {
+		DC_LOG_DEBUG("%s, usb4 request bw timeout\n", __func__);
+		return false;
+	}
+
+	if (stream->signal == SIGNAL_TYPE_DISPLAY_PORT_MST) {
+		int i = 0;
+
+		for (i = 0; i < link->sink_count; i++) {
+			if (link->remote_sinks[i] == NULL)
+				continue;
+			DC_LOG_DEBUG("%s, remote_sink=%s, request_bw=%d\n", __func__,
+					(const char *)(&link->remote_sinks[i]->edid_caps.display_name[0]),
+					link->dpia_bw_alloc_config.remote_sink_req_bw[i]);
+		}
+	}
+
 	return true;
 }