fix: call effective ETH scheduler only from Timer callback

Restrict effective ETH scheduler to Timer callback only.
This is to avoid any race condition on ETH scheduler,
which could previously be called from timer ISR,
as well as  DHCP or UDP driver parts.
Any direct request for ETH scheduler (direct call to stm32_eth_scheduler())
will generate a Timer Update Event to force a call to timer callback

Fixes #45

Signed-off-by: Alexandre Bourdiol <[email protected]>

Author: ABOSTM

src/utility/stm32_eth.cpp

@@ -95,6 +95,8 @@ static uint32_t gEhtLinkTickStart = 0;
 #if !defined(STM32_CORE_VERSION) || (STM32_CORE_VERSION  <= 0x01060100)
   /* Handler for stimer */
   static stimer_t TimHandle;
+#else
+  HardwareTimer *EthTim = NULL;
 #endif
 
 /*************************** Function prototype *******************************/
@@ -103,6 +105,9 @@ static err_t tcp_recv_callback(void *arg, struct tcp_pcb *tpcb, struct pbuf *p,
 static err_t tcp_sent_callback(void *arg, struct tcp_pcb *tpcb, u16_t len);
 static void tcp_err_callback(void *arg, err_t err);
 static void TIM_scheduler_Config(void);
+#if defined(STM32_CORE_VERSION) && (STM32_CORE_VERSION  > 0x01060100)
+  void _stm32_eth_scheduler(void);
+#endif
 
 /**
 * @brief  Configurates the network interface
@@ -148,7 +153,7 @@ static void Netif_Config(void)
 #if (STM32_CORE_VERSION  <= 0x01080000)
   UNUSED(htim);
 #endif
-  stm32_eth_scheduler();
+  _stm32_eth_scheduler();
 }
 
 #if !defined(STM32_CORE_VERSION) || (STM32_CORE_VERSION  <= 0x01060100)
@@ -176,7 +181,7 @@ static void TIM_scheduler_Config(void)
 static void TIM_scheduler_Config(void)
 {
   /* Configure HardwareTimer */
-  HardwareTimer *EthTim = new HardwareTimer(DEFAULT_ETHERNET_TIMER);
+  EthTim = new HardwareTimer(DEFAULT_ETHERNET_TIMER);
   EthTim->setMode(1, TIMER_OUTPUT_COMPARE);
 
   /* Timer set to 1ms */
@@ -265,12 +270,33 @@ uint8_t stm32_eth_link_up(void)
   return netif_is_link_up(&gnetif);
 }
 
+#if defined(STM32_CORE_VERSION) && (STM32_CORE_VERSION  > 0x01060100)
+/**
+  * @brief  This function generates Timer Update event to force call to _stm32_eth_scheduler().
+  * @param  None
+  * @retval None
+  */
+void stm32_eth_scheduler(void)
+{
+  if (EthTim != NULL) {
+    EthTim->refresh();
+  }
+}
+
 /**
-  * @brief  This function must be called in main loop in standalone mode.
+  * @brief  This function is called solely by Timer callback to avoid race condition.
+  * @param  None
+  * @retval None
+  */
+void _stm32_eth_scheduler(void)
+#else
+/**
+  * @brief  This function is called solely by Timer callback to avoid race condition.
   * @param  None
   * @retval None
   */
 void stm32_eth_scheduler(void)
+#endif
 {
   /* Read a received packet from the Ethernet buffers and send it
   to the lwIP for handling */