build/openfpgaloader: Add kwargs support to flash method and some com…

…ments.

litex/build/openfpgaloader.py

@@ -13,31 +13,62 @@ class OpenFPGALoader(GenericProgrammer):
     needs_bitreverse = False
 
     def __init__(self, board="", cable="", freq=0, fpga_part="", index_chain=None):
+        # openFPGALoader base command.
         self.cmd = ["openFPGALoader"]
+
+        # Specify FPGA board.
         if board:
             self.cmd += ["--board", board]
+
+        # Specify FPGA part/device.
         if fpga_part:
             self.cmd += ["--fpga-part", fpga_part]
+
+        # Specify programmation cable.
         if cable:
             self.cmd += ["--cable", cable]
+
+        # Specify programmation frequency.
         if freq:
             self.cmd += ["--freq", str(int(float(freq)))]
+
+        # Specify index in the JTAG chain.
         if index_chain is not None:
             self.cmd += ["--index-chain", str(int(index_chain))]
 
     def load_bitstream(self, bitstream_file):
+        # Load base command.
         cmd = self.cmd + ["--bitstream", bitstream_file]
+
+        # Execute command.
         self.call(cmd)
 
-    def flash(self, address, data_file, external=False, unprotect_flash=False, verify=False):
+    def flash(self, address, data_file, external=False, unprotect_flash=False, verify=False, **kwargs):
+        # Flash base command.
         cmd = self.cmd + ["--write-flash", "--bitstream", data_file]
+
+        # Flash Internal/External selection.
         if external:
             cmd += ["--external-flash"]
+
+        # Flash Offset.
         if address:
             cmd += ["--offset"]
             cmd += [str(address)]
+
+        # Flash Unprotect.
         if unprotect_flash:
             cmd += ["--unprotect-flash"]
+
+        # Flash Verify.
         if verify:
             cmd += ["--verify"]
+
+        # Handle kwargs for specific, less common cases.
+        for key, value in kwargs.items():
+            cmd.append(f"--{key}")
+            if value is not None:
+                cmd.append(str(value))
+
+        # Execute Command.
         self.call(cmd)