Revert "STM32 NuttX driver: Edge-triggered poll(), sort of fixes #35"

This reverts commit 22787651e6.

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

@@ -194,7 +194,8 @@ class CanDriver : public uavcan::ICanDriver, uavcan::Noncopyable
 public:
     template <unsigned RxQueueCapacity>
     CanDriver(CanRxItem (&rx_queue_storage)[UAVCAN_STM32_NUM_IFACES][RxQueueCapacity])
-        : if0_(bxcan::Can[0], update_event_, 0, rx_queue_storage[0], RxQueueCapacity)
+        : update_event_(*this)
+        , if0_(bxcan::Can[0], update_event_, 0, rx_queue_storage[0], RxQueueCapacity)
 #if UAVCAN_STM32_NUM_IFACES > 1
         , if1_(bxcan::Can[1], update_event_, 1, rx_queue_storage[1], RxQueueCapacity)
 #endif

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

@@ -34,9 +34,11 @@ class BusEvent
     chibios_rt::CounterSemaphore sem_;
 
 public:
-    BusEvent()
+    BusEvent(CanDriver& can_driver)
         : sem_(0)
-    { }
+    {
+        (void)can_driver;
+    }
 
     bool wait(uavcan::MonotonicDuration duration);
 
@@ -56,15 +58,13 @@ public:
 
 #elif UAVCAN_STM32_NUTTX
 
-/**
- * All bus events are reported as POLLIN.
- */
 class BusEvent : uavcan::Noncopyable
 {
     static const unsigned MaxPollWaiters = 8;
 
     ::file_operations file_ops_;
     ::pollfd* pollset_[MaxPollWaiters];
+    CanDriver& can_driver_;
     bool signal_;
 
     static int openTrampoline(::file* filp);
@@ -75,13 +75,15 @@ class BusEvent : uavcan::Noncopyable
     int close(::file* filp);
     int poll(::file* filp, ::pollfd* fds, bool setup);
 
+    unsigned makePollMask() const;
+
     int addPollWaiter(::pollfd* fds);
     int removePollWaiter(::pollfd* fds);
 
 public:
     static const char* const DevName;
 
-    BusEvent();
+    BusEvent(CanDriver& can_driver);
     ~BusEvent();
 
     bool wait(uavcan::MonotonicDuration duration);

libuavcan_drivers/stm32/driver/src/uc_stm32_thread.cpp

@@ -99,7 +99,7 @@ int BusEvent::poll(::file* filp, ::pollfd* fds, bool setup)
         ret = addPollWaiter(fds);
         if (ret == 0)
         {
-            fds->revents |= fds->events & POLLIN;
+            fds->revents |= fds->events & makePollMask();
             if (fds->revents != 0)
             {
                 (void)sem_post(fds->sem);
@@ -114,11 +114,26 @@ int BusEvent::poll(::file* filp, ::pollfd* fds, bool setup)
     return ret;
 }
 
+unsigned BusEvent::makePollMask() const
+{
+    const uavcan::CanSelectMasks select_masks = can_driver_.makeSelectMasks();
+    unsigned poll_mask = 0;
+    if (select_masks.read != 0)
+    {
+        poll_mask |= POLLIN;
+    }
+    if (select_masks.write != 0)
+    {
+        poll_mask |= POLLOUT;
+    }
+    return poll_mask;
+}
+
 int BusEvent::addPollWaiter(::pollfd* fds)
 {
     for (unsigned i = 0; i < MaxPollWaiters; i++)
     {
-        if (pollset_[i] == NULL)
+        if (pollset_[i] == nullptr)
         {
             pollset_[i] = fds;
             return 0;
@@ -133,15 +148,16 @@ int BusEvent::removePollWaiter(::pollfd* fds)
     {
         if (fds == pollset_[i])
         {
-            pollset_[i] = NULL;
+            pollset_[i] = nullptr;
             return 0;
         }
     }
     return -EINVAL;
 }
 
-BusEvent::BusEvent()
-    : signal_(false)
+BusEvent::BusEvent(CanDriver& can_driver)
+    : can_driver_(can_driver)
+    , signal_(false)
 {
     std::memset(&file_ops_, 0, sizeof(file_ops_));
     std::memset(pollset_, 0, sizeof(pollset_));
@@ -185,9 +201,9 @@ void BusEvent::signalFromInterrupt()
     for (unsigned i = 0; i < MaxPollWaiters; i++)
     {
         ::pollfd* const fd = pollset_[i];
-        if (fd != NULL)
+        if (fd != nullptr)
         {
-            fd->revents |= fd->events & POLLIN;
+            fd->revents = fd->events & makePollMask();
             if ((fd->revents != 0) && (fd->sem->semcount <= 0))
             {
                 (void)sem_post(fd->sem);