From 036ae93cbbcb73675a03fb59b344d57cbb659f48 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Sat, 30 Dec 2023 08:32:31 +1100
Subject: [PATCH] AP_DroneCAN: reimplement with BinarySemaphore

---
 libraries/AP_DroneCAN/AP_Canard_iface.cpp | 7 +++----
 libraries/AP_DroneCAN/AP_Canard_iface.h   | 2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/libraries/AP_DroneCAN/AP_Canard_iface.cpp b/libraries/AP_DroneCAN/AP_Canard_iface.cpp
index 86bedca40e..ebece89626 100644
--- a/libraries/AP_DroneCAN/AP_Canard_iface.cpp
+++ b/libraries/AP_DroneCAN/AP_Canard_iface.cpp
@@ -406,10 +406,9 @@ void CanardInterface::process(uint32_t duration_ms) {
             WITH_SEMAPHORE(_sem_tx);
             canardCleanupStaleTransfers(&canard, AP_HAL::micros64());
         }
-        uint64_t now = AP_HAL::micros64();
+        const uint64_t now = AP_HAL::micros64();
         if (now < deadline) {
-            _event_handle.wait(MIN(UINT16_MAX - 2U, deadline - now));
-            hal.scheduler->delay_microseconds(50);
+            IGNORE_RETURN(sem_handle.wait(deadline - now));
         } else {
             break;
         }
@@ -436,7 +435,7 @@ bool CanardInterface::add_interface(AP_HAL::CANIface *can_iface)
         AP::can().log_text(AP_CANManager::LOG_ERROR, LOG_TAG, "DroneCANIfaceMgr: Can't alloc uavcan::iface\n");
         return false;
     }
-    if (!can_iface->set_event_handle(&_event_handle)) {
+    if (!can_iface->set_event_handle(&sem_handle)) {
         AP::can().log_text(AP_CANManager::LOG_ERROR, LOG_TAG, "DroneCANIfaceMgr: Setting event handle failed\n");
         return false;
     }
diff --git a/libraries/AP_DroneCAN/AP_Canard_iface.h b/libraries/AP_DroneCAN/AP_Canard_iface.h
index ce9b75ee92..43d786639f 100644
--- a/libraries/AP_DroneCAN/AP_Canard_iface.h
+++ b/libraries/AP_DroneCAN/AP_Canard_iface.h
@@ -72,7 +72,7 @@ private:
     static CanardInterface test_iface;
 #endif
     uint8_t num_ifaces;
-    HAL_EventHandle _event_handle;
+    HAL_BinarySemaphore sem_handle;
     bool initialized;
     HAL_Semaphore _sem_tx;
     HAL_Semaphore _sem_rx;