soc/interconnect/csr: Fix CSR on 64-bit SoC bus width

Currently the code uses the SoC bus width to calculate the alignment of
CSR banks.

However when we get AXI-Lite interconnect support, the CSR bus is not
directly converted from SoC bus now, instead an intermediate bus with
default parameter (which means 32-bit) is created, CSR bus is converted
from it, and finally this bus is attached to the main interconnect with
auto converter if needed. In this case the intermediate bus is always of
32 bit bus width, eliminating the need of caring the SoC bus width when
handling CSR banks.

Tested on 64-bit SoC bus width now; to make the bus further wider,
other codes need to be changed either.

Signed-off-by: Icenowy Zheng <uwu@icenowy.me>

litex/soc/integration/soc.py

@@ -1201,8 +1201,7 @@ class SoC(LiteXModule):
             address_width      = self.csr.address_width,
             alignment          = self.csr.alignment,
             paging             = self.csr.paging,
-            ordering           = self.csr.ordering,
-            soc_bus_data_width = self.bus.data_width)
+            ordering           = self.csr.ordering)
         if len(self.csr.masters):
             self.csr_interconnect = csr_bus.InterconnectShared(
                 masters = list(self.csr.masters.values()),

litex/soc/interconnect/csr_bus.py

@@ -86,11 +86,11 @@ class InterconnectShared(Module):
 # CSR SRAM -----------------------------------------------------------------------------------------
 
 class SRAM(Module):
-    def __init__(self, mem_or_size, address, read_only=None, init=None, bus=None, paging=0x800, soc_bus_data_width=32):
+    def __init__(self, mem_or_size, address, read_only=None, init=None, bus=None, paging=0x800):
         if bus is None:
             bus = Interface()
         self.bus = bus
-        aligned_paging = paging//(soc_bus_data_width//8)
+        aligned_paging = paging//4
         data_width = len(self.bus.dat_w)
         if isinstance(mem_or_size, Memory):
             mem = mem_or_size
@@ -165,11 +165,11 @@ class SRAM(Module):
 # CSR Bank -----------------------------------------------------------------------------------------
 
 class CSRBank(csr.GenericBank):
-    def __init__(self, description, address=0, bus=None, paging=0x800, ordering="big", soc_bus_data_width=32):
+    def __init__(self, description, address=0, bus=None, paging=0x800, ordering="big"):
         if bus is None:
             bus = Interface()
         self.bus = bus
-        aligned_paging = paging//(soc_bus_data_width//8)
+        aligned_paging = paging//4
 
         # # #
 
@@ -205,12 +205,11 @@ class CSRBank(csr.GenericBank):
 # address_map is called exactly once for each object at each call to
 # scan(), so it can have side effects.
 class CSRBankArray(Module):
-    def __init__(self, source, address_map, *ifargs, paging=0x800, ordering="big", soc_bus_data_width=32, **ifkwargs):
+    def __init__(self, source, address_map, *ifargs, paging=0x800, ordering="big", **ifkwargs):
         self.source             = source
         self.address_map        = address_map
         self.paging             = paging
         self.ordering           = ordering
-        self.soc_bus_data_width = soc_bus_data_width
         self.scan(ifargs, ifkwargs)
 
     def scan(self, ifargs, ifkwargs):
@@ -272,8 +271,7 @@ class CSRBankArray(Module):
                 rmap = CSRBank(csrs, mapaddr,
                     bus                = bank_bus,
                     paging             = self.paging,
-                    ordering           = self.ordering,
-                    soc_bus_data_width = self.soc_bus_data_width)
+                    ordering           = self.ordering)
                 self.submodules += rmap
                 self.banks.append((name, csrs, mapaddr, rmap))