STM32: NuttX driver fixed

libuavcan_drivers/stm32/driver/include/uavcan_stm32/can.hpp

@@ -232,6 +232,11 @@ public:
      */
     uavcan::CanSelectMasks makeSelectMasks(const uavcan::CanFrame* (& pending_tx)[uavcan::MaxCanIfaces]) const;
 
+    /**
+     * Whether there's at least one interface where receive() would return a frame.
+     */
+    bool hasReadableInterfaces() const;
+
     /**
      * Returns zero if OK.
      * Returns negative value if failed (e.g. invalid bitrate).

libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp

@@ -706,6 +706,17 @@ uavcan::CanSelectMasks CanDriver::makeSelectMasks(const uavcan::CanFrame* (& pen
     return msk;
 }
 
+bool CanDriver::hasReadableInterfaces() const
+{
+#if UAVCAN_STM32_NUM_IFACES == 1
+	return !if0_.isRxBufferEmpty();
+#elif UAVCAN_STM32_NUM_IFACES == 2
+	return !if0_.isRxBufferEmpty() || !if1_.isRxBufferEmpty();
+#else
+# error UAVCAN_STM32_NUM_IFACES
+#endif
+}
+
 uavcan::int16_t CanDriver::select(uavcan::CanSelectMasks& inout_masks,
                                   const uavcan::CanFrame* (& pending_tx)[uavcan::MaxCanIfaces],
                                   const uavcan::MonotonicTime blocking_deadline)

libuavcan_drivers/stm32/driver/src/uc_stm32_thread.cpp

@@ -105,7 +105,7 @@ int BusEvent::poll(::file* filp, ::pollfd* fds, bool setup)
              *  - Transmission complete. This event is edge-triggered.
              * FIXME Since TX event is edge-triggered, it can be lost between poll() calls.
              */
-            fds->revents |= fds->events & ((can_driver_.makeSelectMasks().read == 0) ? 0 : POLLIN);
+            fds->revents |= fds->events & (can_driver_.hasReadableInterfaces() ? 0 : POLLIN);
             if (fds->revents != 0)
             {
                 (void)sem_post(fds->sem);