soc/integration/soc: Fix CSRBridge Bus Width conversion

Wishbone2CSR and AXILite2CSR bridges are incapable for performing
bus width conversion, which means it's Bus slave port must have same
width as CSRs.

Use CSR width to create slave bus to allow width adaptar to be inserted
by add_slave. Also add relevant assertion.

Signed-off-by: Jiaxun Yang <[email protected]>

litex/soc/integration/soc.py

@@ -1138,13 +1138,14 @@ def add_csr_bridge(self, name="csr", origin=None, register=False):
         }[self.bus.standard]
         csr_bridge_name = f"{name}_bridge"
         self.check_if_exists(csr_bridge_name)
+        data_width = self.csr.data_width
         csr_bridge = csr_bridge_cls(
             bus_bridge_cls(
                 address_width = self.bus.address_width,
-                data_width    = self.bus.data_width),
+                data_width    = data_width),
             bus_csr = csr_bus.Interface(
                 address_width = self.csr.address_width,
-                data_width    = self.csr.data_width),
+                data_width    = data_width),
             register = register)
         self.logger.info("CSR Bridge {} {}.".format(
             colorer(name, color="underline"),

litex/soc/interconnect/axi/axi_lite_to_csr.py

@@ -29,6 +29,8 @@ def __init__(self, axi_lite=None, bus_csr=None, register=False):
         self.axi_lite = axi_lite
         self.csr      = bus_csr
 
+        assert axi_lite.data_width == bus_csr.data_width
+
         fsm, comb = axi_lite_to_simple(
             axi_lite   = self.axi_lite,
             port_adr   = self.csr.adr,

litex/soc/interconnect/wishbone.py

@@ -588,6 +588,8 @@ def __init__(self, bus_wishbone=None, bus_csr=None, register=True):
             # If no Wishbone bus provided, create it with default parameters.
             self.wishbone = Interface()
 
+        assert self.wishbone.data_width == self.csr.data_width
+
         # # #
 
         wishbone_adr_shift = {