rfnoc: Add support for Split Stream RFNoC block

The split stream RFNoC block is an RFNoC block that takes in a single
CHDR stream and duplicates it, creating a number of output streams for
each input stream. Consult the split_stream_block_control class header
file for more details on block configuration and behavior, including how
property and action forwarding is handled by the block.

3 files changed, 65 insertions, 0 deletions

diff --git a/host/include/uhd/rfnoc/CMakeLists.txt b/host/include/uhd/rfnoc/CMakeLists.txt
index 24409fbf9..f86c04850 100644
--- a/host/include/uhd/rfnoc/CMakeLists.txt
+++ b/host/include/uhd/rfnoc/CMakeLists.txt
@@ -39,6 +39,7 @@ UHD_INSTALL(FILES
     fosphor_block_control.hpp
     null_block_control.hpp
     radio_control.hpp
+    split_stream_block_control.hpp
     vector_iir_block_control.hpp
 
     DESTINATION ${INCLUDE_DIR}/uhd/rfnoc
diff --git a/host/include/uhd/rfnoc/defaults.hpp b/host/include/uhd/rfnoc/defaults.hpp
index 053834335..ba9907a11 100644
--- a/host/include/uhd/rfnoc/defaults.hpp
+++ b/host/include/uhd/rfnoc/defaults.hpp
@@ -77,6 +77,7 @@ static const noc_id_t DUC_BLOCK        = 0xD0C00000;
 static const noc_id_t DDC_BLOCK        = 0xDDC00000;
 static const noc_id_t FIR_FILTER_BLOCK = 0xf1120000;
 static const noc_id_t FOSPHOR_BLOCK    = 0x666F0000;
+static const noc_id_t SPLIT_STREAM_BLOCK = 0x57570000;
 static const noc_id_t VECTOR_IIR_BLOCK = 0x11120000;
 
 }} // namespace uhd::rfnoc
diff --git a/host/include/uhd/rfnoc/split_stream_block_control.hpp b/host/include/uhd/rfnoc/split_stream_block_control.hpp
new file mode 100644
index 000000000..596d7f19c
--- /dev/null
+++ b/host/include/uhd/rfnoc/split_stream_block_control.hpp
@@ -0,0 +1,63 @@
+//
+// Copyright 2020 Ettus Research, a National Instruments Brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#pragma once
+
+#include <uhd/config.hpp>
+#include <uhd/rfnoc/noc_block_base.hpp>
+
+namespace uhd { namespace rfnoc {
+
+/*! Split Stream Block Control Class
+ *
+ * The Split Stream Block is an RFNoC block that takes in a single CHDR
+ * stream and duplicates it, creating a number of output streams for each
+ * input stream. The number of streams is defined by the NUM_PORTS parameter
+ * used to instantiate the RFNoC block in the image, while the number of
+ * output branches is defined by the NUM_BRANCH parameter. In software, this
+ * corresponds to an RFNoC block having NUM_PORTS input ports and
+ * NUM_PORTS * NUM_BRANCH output ports.
+ *
+ * Given the following example of a split stream RFNoC block with
+ * NUM_PORTS = 2 and NUM_BRANCH = 3, the input streams map to output branches
+ * and streams as follows. The number located at each input and output
+ * indicates the port number corresponding to that stream and branch:
+ *
+ *                  +----------+
+ *     Stream A --->|0        0|---> Stream A } Branch 0
+ *     Stream B --->|1        1|---> Stream B
+ *                  |         2|---> Stream A } Branch 1
+ *                  |         3|---> Stream B
+ *                  |         4|---> Stream A } Branch 2
+ *                  |         5|---> Stream B
+ *                  +----------+
+ *
+ * In other words, the port number corresponding to stream S of branch B is
+ * given by B * (num_input_ports) + S.
+ *
+ * \section ss_fwd_behavior Property Propagation and Action Forwarding Behavior
+ *
+ * The default behavior of the split stream block controller is to propagate
+ * properties received on a particular stream to all branches of that stream.
+ * For example, if a property is received at branch 0, stream B in the example
+ * above, that property will be propagated to stream B in branches 1 and 2
+ * AND to stream B in the input. The property will not propagate across
+ * streams.
+ *
+ * For actions, an action received on a particular stream is forwarded to
+ * that stream on *all opposite* branches. If in the example above, an action
+ * is received at branch 2, stream A, it will be forwarded to stream A on the
+ * input side. Similarly, if an action is received on stream B of the input,
+ * it will be forwarded to stream B on branches 0, 1, AND 2.
+ */
+class UHD_API split_stream_block_control : public noc_block_base
+{
+public:
+    RFNOC_DECLARE_BLOCK(split_stream_block_control)
+};
+
+}} // namespace uhd::rfnoc
+