soc/integration/common: Improve get_mem_data error reporting.

litex/soc/integration/common.py

@@ -20,11 +20,13 @@ def get_version(with_time=True):
     return datetime.datetime.fromtimestamp(time.time()).strftime(fmt)
 
 def get_mem_data(filename_or_regions, endianness="big", mem_size=None):
-    # create memory regions
+    # Create memory regions.
     if isinstance(filename_or_regions, dict):
         regions = filename_or_regions
     else:
         filename = filename_or_regions
+        if not os.path.isfile(filename):
+            raise OSError(f"Unable to find {filename} memory content file.")
         _, ext = os.path.splitext(filename)
         if ext == ".json":
             f = open(filename, "r")
@@ -33,9 +35,11 @@ def get_mem_data(filename_or_regions, endianness="big", mem_size=None):
         else:
             regions = {filename: "0x00000000"}
 
-    # determine data_size
+    # Determine data_size.
     data_size = 0
     for filename, base in regions.items():
+        if not os.path.isfile(filename):
+            raise OSError(f"Unable to find {filename} memory content file.")
         data_size = max(int(base, 16) + os.path.getsize(filename), data_size)
     assert data_size > 0
     if mem_size is not None:
@@ -43,7 +47,7 @@ def get_mem_data(filename_or_regions, endianness="big", mem_size=None):
             "file is too big: {}/{} bytes".format(
              data_size, mem_size))
 
-    # fill data
+    # Fill data.
     data = [0]*math.ceil(data_size/4)
     for filename, base in regions.items():
         with open(filename, "rb") as f: