feat: Raspberry Pi 4/400 Bluetooth over mini UART (H4, Broadcom patchram, firmware mailbox BT_ON); move BT stack to Drivers/Bluetooth

kernel/src/Timekeeping/Timer.cpp

@@ -19,7 +19,8 @@
 #include <Drivers/Net/Wifi/Wifi.hpp>
 #include <Drivers/Audio/IntelHda.hpp>
 #include <Drivers/USB/Xhci.hpp>
-#include <Drivers/USB/Bluetooth/Bluetooth.hpp>
+#include <Drivers/Bluetooth/Bluetooth.hpp>
+#include <Drivers/Serial/BtUart.hpp>
 #include <Drivers/USB/HidKeyboard.hpp>
 
 using namespace Kt;
@@ -58,7 +59,10 @@ namespace Timekeeping {
             // desktop may never enter idle. Force one bounded idle-context
             // pass for USB immediately, and for network RX at most every
             // 10 ms (important for E1000E's polling fallback).
-            bool usbWork = Drivers::USB::Xhci::HasDeferredWork();
+            // UART Bluetooth (Raspberry Pi) has no xHCI behind it: its
+            // received bytes wait in the UART ring for the same pass.
+            bool usbWork = Drivers::USB::Xhci::HasDeferredWork() ||
+                           Drivers::Serial::BtUart::HasRxData();
             bool audioWork = Drivers::Audio::IntelHda::HasDeferredWork();
             bool netWork = Drivers::Net::E1000::HasDeferredWork() ||
                            Drivers::Net::E1000E::HasDeferredWork();
@@ -185,9 +189,9 @@ namespace Timekeeping {
         // Cheap no-op unless an adapter is waiting; self-claiming, and safe
         // to preempt (the scheduler saves/resumes the idle context).
         bool bluetoothWork = usbWork ||
-            Drivers::USB::Bluetooth::HasDeferredWork();
+            Drivers::Bluetooth::HasDeferredWork();
         if (bluetoothWork)
-            Drivers::USB::Bluetooth::ServiceDeferredInit();
+            Drivers::Bluetooth::ServiceDeferredInit();
 
         // Service Bluetooth inbound traffic (the headset's SDP/AVRCP queries,
         // AVDTP commands, ACL flow-control credits) whenever a core idles.
@@ -197,7 +201,7 @@ namespace Timekeeping {
         // queries never answered).  Self-serializing and a cheap no-op when
         // the adapter is down.
         if (bluetoothWork)
-            Drivers::USB::Bluetooth::ServiceEvents();
+            Drivers::Bluetooth::ServiceEvents();
 
         // Wi-Fi mirrors the Bluetooth split: the firmware load needs the
         // ramdisk, and the RX/notification ring must be drained outside hard