Support connectivity in axi_intercon_gen

This introduces support for partial connectivity in the axi_intercon
generator. Also adds the missing PipelineStages parameter.

axi.core

@@ -137,11 +137,15 @@ generators:
 
                    offset (int): Base address for the slave
                    size   (int): Size of the allocated memory map for the slave
+                   slaves (list): List of device ports that this host is
+                                  connected to. A missing or empty list means
+                                  connection to all devices.
 
       Example usage:
         The following config will generate an interconnect wrapper to which two
         AXI4 master interfaces (dma and ibus) with different id widths are
         connected, and connects downstream to three AXI4 slaves (rom, gpio, ram)
+        The ibus port is only allowed to access the rom and ram ports.
 
         soc_intercon:
           generator: axi_intercon_gen
@@ -151,6 +155,7 @@ generators:
                 id_width : 1
               ibus:
                 id_width : 2
+                slaves: [ram, rom]
             slaves:
               ram:
                 offset : 0

scripts/axi_intercon_gen.py

@@ -200,13 +200,12 @@ def load_dict(self, d):
         for key, value in d.items():
             if key == 'slaves':
                 # Handled in file loading, ignore here
-                continue
-            if key == 'id_width':
+                self.slaves = value
+            elif key == 'id_width':
                 self.idw = value
             elif key == 'read_only':
                 self.read_only = value
             else:
-                print(key)
                 raise UnknownPropertyError(
                     "Unknown property '%s' in master section '%s'" % (
                     key, self.name))
@@ -349,6 +348,7 @@ def write(self):
     MaxSlvTrans:        6,
     FallThrough:        1'b0,
     LatencyMode:        axi_pkg::CUT_ALL_AX,
+    PipelineStages:     0,
     AxiIdWidthSlvPorts: AxiIdWidthMasters,
     AxiIdUsedSlvPorts:  AxiIdUsed,
     UniqueIds:          1'b0,
@@ -403,14 +403,26 @@ def write(self):
         raw += "   mst_req_t  [{}:0] slaves_req;\n".format(ns-1)
         raw += "   mst_resp_t [{}:0] slaves_resp;\n".format(ns-1)
 
-        ns = len(self.slaves)
+        raw += f"\n  localparam bit [{nm-1}:0][{ns-1}:0] connectivity = " + '{\n   {'
+        connmap = []
+        for master in self.masters:
+            connstr = f"{ns}'b"
+            if master.slaves:
+                for slave in self.slaves:
+                    connstr += '1' if slave.name in master.slaves else '0'
+            else:
+                connstr += '1'*ns
+            connmap.append(connstr)
+        raw += "},\n   {".join(connmap)
+        raw += "}};\n"
 
         raw += assigns(w, max_idw, self.masters, self.slaves)
 
         self.verilog_writer.raw = raw
         parameters = [
             Parameter('Cfg'          , 'xbar_cfg' ),
             Parameter('ATOPs'        , "1'b"+str(int(self.atop))),
+            Parameter('Connectivity' , 'connectivity'),
             Parameter('slv_aw_chan_t', 'aw_chan_mst_t'),
             Parameter('mst_aw_chan_t', 'aw_chan_slv_t'),
             Parameter('w_chan_t'     , 'w_chan_t'     ),