diff --git a/litex/soc/integration/export.py b/litex/soc/integration/export.py
index ecd474669..3a00b88f7 100644
--- a/litex/soc/integration/export.py
+++ b/litex/soc/integration/export.py
@@ -257,13 +257,14 @@ def get_csr_header(regions, constants, csr_base=None, with_csr_base_define=True,
         r += "#ifndef CSR_ACCESSORS_DEFINED\n"
         r += "#include <hw/common.h>\n"
         r += "#endif /* ! CSR_ACCESSORS_DEFINED */\n"
-    csr_base = csr_base if csr_base is not None else regions[next(iter(regions))].origin
+    _csr_base = regions[next(iter(regions))].origin
+    csr_base = csr_base if csr_base is not None else _csr_base
     if with_csr_base_define:
-        r += "#ifndef CSR_BASE\n"
+        r += "\n#ifndef CSR_BASE\n"
         r += f"#define CSR_BASE {hex(csr_base)}L\n"
         r += "#endif\n"
     for name, region in regions.items():
-        origin = region.origin - csr_base
+        origin = region.origin - _csr_base
         r += "\n/* "+name+" */\n"
         r += f"#define CSR_{name.upper()}_BASE {_get_csr_addr(csr_base, origin, with_csr_base_define)}\n"
         if not isinstance(region.obj, Memory):