Add PE_SNK_Not_Supported_Received state

This state requires that the DPM be informed of the receipt of a
Not_Supported message.  Some DPMs may not need to do this, so the new
dpm.not_supported_received function is optional.

lib/include/pdb_dpm.h

      * omitted.
      */
     pdb_dpm_func transition_typec;
+
+    /*
+     * Handle a received Not_Supported message.
+     *
+     * Optional.  If no special handling is needed, this may be omitted.
+     */
+    pdb_dpm_func not_supported_received;
 };
 
 

lib/src/policy_engine.c

     PESinkSendSoftReset,
     PESinkSendNotSupported,
     PESinkChunkReceived,
+    PESinkNotSupportedReceived,
     PESinkSourceUnresponsive
 };
 
                     chPoolFree(&pdb_msg_pool, cfg->pe._message);
                     cfg->pe._message = NULL;
                     return PESinkChunkReceived;
+                /* Tell the DPM a message we sent got a response of
+                 * Not_Supported. */
+                } else if (PD_MSGTYPE_GET(cfg->pe._message) == PD_MSGTYPE_NOT_SUPPORTED
+                        && PD_NUMOBJ_GET(cfg->pe._message) == 0) {
+                    chPoolFree(&pdb_msg_pool, cfg->pe._message);
+                    cfg->pe._message = NULL;
+                    return PESinkNotSupportedReceived;
                 /* If we got an unknown message, send a soft reset */
                 } else {
                     chPoolFree(&pdb_msg_pool, cfg->pe._message);
     return PESinkSendNotSupported;
 }
 
+static enum policy_engine_state pe_sink_not_supported_received(struct pdb_config *cfg)
+{
+    /* Inform the Device Policy Manager that we received a Not_Supported
+     * message. */
+    if (cfg->dpm.not_supported_received != NULL) {
+        cfg->dpm.not_supported_received(cfg);
+    }
+
+    return PESinkReady;
+}
+
 /*
  * When Power Delivery is unresponsive, fall back to Type-C Current
  */
             case PESinkSourceUnresponsive:
                 state = pe_sink_source_unresponsive(cfg);
                 break;
+            case PESinkNotSupportedReceived:
+                state = pe_sink_not_supported_received(cfg);
+                break;
             default:
                 /* This is an error.  It really shouldn't happen.  We might
                  * want to handle it anyway, though. */

src/main.c

         pdbs_dpm_transition_min,
         pdbs_dpm_transition_standby,
         pdbs_dpm_transition_requested,
-        pdbs_dpm_transition_requested /* XXX type-c current */
+        pdbs_dpm_transition_requested, /* XXX type-c current */
+        NULL
     },
     .dpm_data = &dpm_data
 };