drm/dp_mst: Add DSC enablement helpers to DRM

[linux.git] / drivers / gpu / drm / drm_dp_mst_topology.c

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 90201827781d3e43e6e2a065b1bc0a0bfad520e1..9f7e714c518256ce6cd16a1429af7017b1f6e427 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -4789,6 +4789,67 @@ drm_dp_mst_atomic_check_topology_state(struct drm_dp_mst_topology_mgr *mgr,
        return 0;
 }
 
+/**
+ * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
+ * @state: Pointer to the new drm_atomic_state
+ * @port: Pointer to the affected MST Port
+ * @pbn: Newly recalculated bw required for link with DSC enabled
+ * @pbn_div: Divider to calculate correct number of pbn per slot
+ * @enable: Boolean flag to enable or disable DSC on the port
+ *
+ * This function enables DSC on the given Port
+ * by recalculating its vcpi from pbn provided
+ * and sets dsc_enable flag to keep track of which
+ * ports have DSC enabled
+ *
+ */
+int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
+                                struct drm_dp_mst_port *port,
+                                int pbn, int pbn_div,
+                                bool enable)
+{
+       struct drm_dp_mst_topology_state *mst_state;
+       struct drm_dp_vcpi_allocation *pos;
+       bool found = false;
+       int vcpi = 0;
+
+       mst_state = drm_atomic_get_mst_topology_state(state, port->mgr);
+
+       if (IS_ERR(mst_state))
+               return PTR_ERR(mst_state);
+
+       list_for_each_entry(pos, &mst_state->vcpis, next) {
+               if (pos->port == port) {
+                       found = true;
+                       break;
+               }
+       }
+
+       if (!found) {
+               DRM_DEBUG_ATOMIC("[MST PORT:%p] Couldn't find VCPI allocation in mst state %p\n",
+                                port, mst_state);
+               return -EINVAL;
+       }
+
+       if (pos->dsc_enabled == enable) {
+               DRM_DEBUG_ATOMIC("[MST PORT:%p] DSC flag is already set to %d, returning %d VCPI slots\n",
+                                port, enable, pos->vcpi);
+               vcpi = pos->vcpi;
+       }
+
+       if (enable) {
+               vcpi = drm_dp_atomic_find_vcpi_slots(state, port->mgr, port, pbn, pbn_div);
+               DRM_DEBUG_ATOMIC("[MST PORT:%p] Enabling DSC flag, reallocating %d VCPI slots on the port\n",
+                                port, vcpi);
+               if (vcpi < 0)
+                       return -EINVAL;
+       }
+
+       pos->dsc_enabled = enable;
+
+       return vcpi;
+}
+EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
 /**
  * drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
  * atomic update is valid