WFI with interrupt-driven wakeup for USB and W6300

firmware/lib/dispatch.cpp

@@ -8,6 +8,7 @@
 #include "timer_queue.h"
 #include "net.h"
 #include "debug_log.h"
+#include "hardware/sync.h"
 
 static timer_queue timers;
 
@@ -39,6 +40,8 @@ void dispatch_schedule_ms(uint32_t ms, std::function<void()> fn) {
     });
 
     while (true) {
+        uint32_t save = save_and_disable_interrupts();
+
         dlog_if_slow("tud_task", 1000, [&]{ tud_task(); });
         dlog_if_slow("drain", 1000, [&]{ usb.drain(); });
         dlog_if_slow("timers", 1000, [&]{ timers.run(); });
@@ -76,6 +79,7 @@ void dispatch_schedule_ms(uint32_t ms, std::function<void()> fn) {
             }
         }
 
-        // __wfi();
+        __wfi();
+        restore_interrupts(save);
     }
 }