arbitrate a parameterised Read interface and forward requests to a single

Read interface (contrast with ArbitratedReadC)

diff --git a/tos/system/MultiplexedReadC.nc b/tos/system/MultiplexedReadC.nc
new file mode 100644 (file)
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+++ b/tos/system/MultiplexedReadC.nc
@@ -0,0 +1,46 @@
+/* $Id$
+ * Copyright (c) 2005 Intel Corporation
+ * All rights reserved.
+ *
+ * This file is distributed under the terms in the attached INTEL-LICENSE     
+ * file. If you do not find these files, copies can be found by writing to
+ * Intel Research Berkeley, 2150 Shattuck Avenue, Suite 1300, Berkeley, CA, 
+ * 94704.  Attention:  Intel License Inquiry.
+ */
+/**
+ * Multiplex access to a single Read interface for a parameterised
+ * Read interface whose access is controlled by an arbiter.
+ *
+ * @param width_t Width of the underlying Read interface.
+ *
+ * @author David Gay
+ */
+generic module MultiplexedReadC(typedef width_t) {
+  provides interface Read<width_t>[uint8_t client];
+  uses {
+    interface Read<width_t> as Service;
+    interface Resource[uint8_t client];
+  }
+}
+implementation {
+  command error_t Read.read[uint8_t client]() {
+    return call Resource.request[client]();
+  }
+
+  event void Resource.granted[uint8_t client]() {
+    call Service.read();
+  }
+
+  event void Service.readDone(error_t result, width_t data) {
+    uint8_t client = call ArbiterInfo.userId();
+
+    call Resource.release[client]();
+    signal Read.readDone[client](result, data);
+  }
+
+  default async command error_t Resource.request[uint8_t client]() { 
+    return FAIL; 
+  }
+  default async command error_t Resource.release[uint8_t client]() { return FAIL; }
+  default event void Read.readDone[uint8_t client](error_t result, width_t data) { }
+}