soc/add_master: Add region support to allow remapping.

Allow connecting a master to a specific region of the SoC and limiting access to it.

litex/soc/integration/soc.py

@@ -447,7 +447,34 @@ class SoCBusHandler(LiteXModule):
 
         return adapted_interface
 
-    def add_master(self, name=None, master=None):
+    # Add Remapper ---------------------------------------------------------------------------------
+    def add_remapper(self, name, interface, origin, size):
+        interface_cls = type(interface)
+        remapper_cls  = {
+            wishbone.Interface   : wishbone.Remapper,
+            axi.AXILiteInterface : axi.AXILiteRemapper,
+            axi.AXIInterface     : axi.AXIRemapper,
+        }[interface_cls]
+
+        adapted_interface = interface_cls(
+            data_width    = interface.data_width,
+            address_width = interface.address_width,
+            addressing    = interface.addressing,
+        )
+
+        self.submodules += remapper_cls(interface, adapted_interface, origin, size)
+
+        fmt = "{name} Bus {remapped} to {origin} (Size: {size})."
+        self.logger.info(fmt.format(
+            name     = colorer(name),
+            remapped = colorer("remapped", color="cyan"),
+            origin   = colorer(f"0x{origin:08x}"),
+            size     = colorer(f"0x{size:08x}"),
+        ))
+
+        return adapted_interface
+
+    def add_master(self, name=None, master=None, region=None):
         if name is None:
             name = "master{:d}".format(len(self.masters))
         if name in self.masters.keys():
@@ -456,6 +483,8 @@ class SoCBusHandler(LiteXModule):
                 colorer("already declared", color="red")))
             self.logger.error(self)
             raise SoCError()
+        if region:
+            master = self.add_remapper(name, master, region.origin, region.size)
         master = self.add_adapter(name, master, "m2s")
         self.masters[name] = master
         self.logger.info("{} {} as Bus Master.".format(

litex/soc/interconnect/axi/axi_full.py

@@ -7,6 +7,8 @@
 
 """AXI4-Full/Lite support for LiteX"""
 
+from math import log2
+
 from migen import *
 from migen.genlib import roundrobin
 
@@ -138,6 +140,18 @@ class AXIInterface:
     def layout_flat(self):
         return list(axi_layout_flat(self))
 
+# AXI Remapper -------------------------------------------------------------------------------------
+
+class AXIRemapper(LiteXModule):
+    def __init__(self, master, slave, origin, size):
+        # Mask.
+        mask = 2**int(log2(size)) - 1
+
+        # Address Mask and Shift.
+        self.comb += master.connect(slave)
+        self.comb += slave.aw.addr.eq(origin | master.aw.addr & mask)
+        self.comb += slave.ar.addr.eq(origin | master.ar.addr & mask)
+
 # AXI Bursts to Beats ------------------------------------------------------------------------------
 
 class AXIBurst2Beat(LiteXModule):

litex/soc/interconnect/axi/axi_lite.py

@@ -7,6 +7,8 @@
 
 """AXI4-Full/Lite support for LiteX"""
 
+from math import log2
+
 from migen import *
 from migen.genlib import roundrobin
 
@@ -128,6 +130,19 @@ class AXILiteInterface:
         yield self.r.ready.eq(0)
         return (data, resp)
 
+
+# AXI-Lite Remapper --------------------------------------------------------------------------------
+
+class AXILiteRemapper(LiteXModule):
+    def __init__(self, master, slave, origin, size):
+        # Mask.
+        mask = 2**int(log2(size)) - 1
+
+        # Address Mask and Shift.
+        self.comb += master.connect(slave)
+        self.comb += slave.aw.addr.eq(origin | master.aw.addr & mask)
+        self.comb += slave.ar.addr.eq(origin | master.ar.addr & mask)
+
 # AXI-Lite to Simple Bus ---------------------------------------------------------------------------
 
 def axi_lite_to_simple(axi_lite, port_adr, port_dat_r, port_dat_w=None, port_we=None):

litex/soc/interconnect/wishbone.py

@@ -126,6 +126,24 @@ class Interface(Record):
                     r.append(sig.eq(pad))
         return r
 
+# Wishbone Remapper --------------------------------------------------------------------------------
+
+class Remapper(LiteXModule):
+    def __init__(self, master, slave, origin, size):
+        # Parameters.
+        addressing = master.addressing
+        assert master.addressing == slave.addressing
+
+        # Mask.
+        log2_size = int(log2(size))
+        if addressing == "word":
+            log2_size -= int(log2(len(master.dat_w)//8))
+        mask = 2**log2_size - 1
+
+        # Address Mask and Shift.
+        self.comb += master.connect(slave, omit={"adr"})
+        self.comb += slave.adr.eq(origin | (master.adr & mask))
+
 # Wishbone Timeout ---------------------------------------------------------------------------------
 
 class Timeout(LiteXModule):