drm/dp_mst: add a function to retrieve vcpi slots

radeon requires this to get the slots for later filling
out a table on every transition.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 9a5b68717ec8..0d15e6e30732 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -2319,6 +2319,19 @@ out:
 }
 EXPORT_SYMBOL(drm_dp_mst_allocate_vcpi);
 
+int drm_dp_mst_get_vcpi_slots(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port)
+{
+        int slots = 0;
+        port = drm_dp_get_validated_port_ref(mgr, port);
+        if (!port)
+                return slots;
+
+        slots = port->vcpi.num_slots;
+        drm_dp_put_port(port);
+        return slots;
+}
+EXPORT_SYMBOL(drm_dp_mst_get_vcpi_slots);
+
 /**
  * drm_dp_mst_reset_vcpi_slots() - Reset number of slots to 0 for VCPI
  * @mgr: manager for this port