add cpo bailly cmis firmware upgrade api

sonic_platform_base/sonic_xcvr/api/broadcom/bailly.py

@@ -5,6 +5,7 @@
 """
 from ..public.cmis import CmisApi
 from ...fields.broadcom import bailly
+from ...cdb.broadcom.bailly import BaillyCdbFwHandler
 
 class BaillyApi(CmisApi):
     RLM_THRESHOLD_FIELDS = {
@@ -376,3 +377,22 @@ def get_laser_temperature(self):
         Bailly has no laser temperature acquisition register, return none.
         """
         return None
+
+    # Override cdb_fw_hdlr property from parent CmisCdbFw
+    @property
+    def cdb_fw_hdlr(self):
+        if not self._init_cdb_fw_handler:
+            return None
+        if self._cdb_fw_hdlr is None:
+            # Instantiate vendor-specific BaillyCdbFwHandler instead of base CdbFwHandler
+            self._cdb_fw_hdlr = BaillyCdbFwHandler(
+                self.xcvr_eeprom.reader,
+                self.xcvr_eeprom.writer,
+                self._cdb_mem_map,
+            )
+        return self._cdb_fw_hdlr
+    # Override firmware upgreade function
+    def module_fw_upgrade(self, imagepath, timeout=5):
+        #Todo parse firmware hearder
+        # load/run/commit
+        pass

sonic_platform_base/sonic_xcvr/cdb/broadcom/bailly.py

@@ -0,0 +1,18 @@
+from ...cdb.cdb_fw import CdbFwHandler
+
+# Vendor custom CDB handler inheriting base community handler
+class BaillyCdbFwHandler(CdbFwHandler):
+    def __init__(self, reader, writer, cdb_map):
+        super().__init__(reader, writer, cdb_map)
+
+    # Reuse parent implementation for consistent opcodes (no override needed)
+    # Override single opcode method only if Bailly hardware has different logic
+    def write_epl_block(self, address, data):
+        # Example: OE firmware strip 4-byte header, vendor custom logic
+        stripped = data[4:]
+        return super().write_epl_block(address, stripped)
+    # Override start download to inject CPO partition ID (0x0101)
+    def start_fw_download(self, filepath):
+        # Inject CPO partition info before parent download initialization
+        # Todo
+        return super().start_fw_download(filepath)