Keep nRF52 Full Companion BLE subscriptions across reconnects

scripts/nrf52_ble_cccd_fix.py

@@ -3,8 +3,8 @@
 The pinned core saves every bonded CCCD write from its callback worker into
 InternalFS. On a T1000-E Full Companion this reproducibly resets the radio as
 the client enables notifications, even after formatting InternalFS. Bond-key
-persistence still works. The Companion client re-subscribes on connection;
-this workaround sacrifices CCCD persistence, not key-based reconnection.
+persistence still works. The Companion keeps recent CCCD state in RAM across
+BLE reconnects, without a live flash write.
 Patch a private build copy; never edit PlatformIO's shared framework cache.
 """
 
@@ -21,6 +21,25 @@ FIXED_SAVE = """      {
 #endif
       }
 """
+OLD_LOAD = "        if ( !loadCccd() )  sd_ble_gatts_sys_attr_set(_conn_hdl, NULL, 0, 0);\n"
+FIXED_LOAD = """#if defined(COMPANION_RADIO_FULL) && COMPANION_RADIO_FULL
+        if ( !mesh_nrf52_restore_ram_cccd(_conn_hdl, &_bond_id_addr) &&
+             !loadCccd() )
+        {
+          sd_ble_gatts_sys_attr_set(_conn_hdl, NULL, 0, 0);
+        }
+#else
+        if ( !loadCccd() )  sd_ble_gatts_sys_attr_set(_conn_hdl, NULL, 0, 0);
+#endif
+"""
+OLD_CONNECTION_INCLUDE = '#include "bluefruit.h"\n'
+FIXED_CONNECTION_INCLUDE = """#include "bluefruit.h"
+
+#if defined(COMPANION_RADIO_FULL) && COMPANION_RADIO_FULL
+bool mesh_nrf52_restore_ram_cccd(uint16_t conn_handle,
+                                  const ble_gap_addr_t* peer);
+#endif
+"""
 
 
 def patched_source(source):
@@ -34,20 +53,36 @@ def patched_source(source):
     return source.replace(OLD_SAVE, FIXED_SAVE)
 
 
+def patched_connection_source(source):
+    source = source.replace("\r\n", "\n")
+    if FIXED_LOAD in source and FIXED_CONNECTION_INCLUDE in source:
+        return source
+    if source.count(OLD_LOAD) != 1 or source.count(OLD_CONNECTION_INCLUDE) != 1:
+        raise RuntimeError(
+            "nRF52 BLE CCCD fix: unrecognized BLEConnection source; review before building"
+        )
+    return source.replace(OLD_CONNECTION_INCLUDE, FIXED_CONNECTION_INCLUDE).replace(
+        OLD_LOAD, FIXED_LOAD
+    )
+
+
 def replace_framework_source(build_env, node):
     source = Path(node.srcnode().get_abspath())
-    if source.name != "BLEGatt.cpp" or source.parent.name != "src":
+    if source.name not in ("BLEGatt.cpp", "BLEConnection.cpp") or source.parent.name != "src":
         return node
-    patched = patched_source(source.read_text(encoding="utf-8"))
+    original = source.read_text(encoding="utf-8")
+    patched = (patched_source(original) if source.name == "BLEGatt.cpp"
+               else patched_connection_source(original))
     build_env.AppendUnique(CPPPATH=[str(source.parent)])
-    destination = Path(build_env.subst("$BUILD_DIR")) / "patched-nrf52-ble" / "BLEGatt.cpp"
+    destination = Path(build_env.subst("$BUILD_DIR")) / "patched-nrf52-ble" / source.name
     destination.parent.mkdir(parents=True, exist_ok=True)
     if not destination.exists() or destination.read_text(encoding="utf-8") != patched:
         destination.write_text(patched, encoding="utf-8")
-    print("nRF52 BLE: Full Companion CCCD persistence workaround enabled")
+    print(f"nRF52 BLE: Full Companion CCCD workaround in {source.name}")
     return build_env.File(str(destination))
 
 
 if "Import" in globals():
     Import("env")
     env.AddBuildMiddleware(replace_framework_source, "*BLEGatt.cpp")
+    env.AddBuildMiddleware(replace_framework_source, "*BLEConnection.cpp")