emac: stm32: check inteface status before link_out()

This allows handling of HAL_ETH_STATE_ERROR, usually on interface teardown/up with strict timings

Author: maidnl

connectivity/drivers/emac/TARGET_STM/stm32xx_emac.cpp

@@ -402,6 +402,33 @@ bool STM32_EMAC::low_level_init_successful()
 }
 #endif // ETH_IP_VERSION_V2
 
+/**
+ * This function get the state of emac interface
+ */
+int STM32_EMAC::get_interface_status() {
+    return HAL_ETH_GetState(&EthHandle);
+}
+
+/**
+ * This function returns true if the status of the interface is in the
+ * correct state for the trasmission
+ */
+bool STM32_EMAC::is_ready_to_tx() {
+    return (HAL_ETH_GetState(&EthHandle) == HAL_ETH_STATE_READY);
+}
+
+/**
+ * This function reset the emac interface in case the status is in error
+ * Apparently there was not anything to recover from an error state
+ */
+void STM32_EMAC::restart() {
+    if(HAL_ETH_STATE_ERROR == HAL_ETH_GetState(&EthHandle)){
+        HAL_ETH_Stop(&EthHandle);
+        HAL_ETH_Start(&EthHandle);
+    }
+}
+
+
 /**
  * This function should do the actual transmission of the packet. The packet is
  * contained in the memory buffer chain that is passed to the function.

connectivity/drivers/emac/TARGET_STM/stm32xx_emac.h

@@ -148,6 +148,13 @@ class STM32_EMAC : public EMAC {
      */
     virtual void set_memory_manager(EMACMemoryManager &mem_mngr);
 
+    /* return the status of the interface as integer */
+    int get_interface_status() override;
+    /* return true if the interface is in the correct state to transmit */
+    bool is_ready_to_tx() override;
+    /* restart only if the interface is in error state */
+    void restart() override;
+
     // Called from driver functions
     ETH_HandleTypeDef EthHandle;
     osThreadId_t thread; /**< Processing thread */

connectivity/lwipstack/source/LWIPInterfaceEMAC.cpp

@@ -27,15 +27,26 @@
 
 #if LWIP_ETHERNET
 
+
 err_t LWIP::Interface::emac_low_level_output(struct netif *netif, struct pbuf *p)
 {
+    bool ret = false;
     /* Increase reference counter since lwip stores handle to pbuf and frees
        it after output */
     pbuf_ref(p);
 
     LWIP::Interface *mbed_if = static_cast<LWIP::Interface *>(netif->state);
-    bool ret = mbed_if->emac->link_out(p);
-    return ret ? ERR_OK : ERR_IF;
+
+    if(mbed_if->emac->is_ready_to_tx()) {
+        ret = mbed_if->emac->link_out(p);
+    }
+    else {
+        mbed_if->emac->restart();
+        ret = mbed_if->emac->link_out(p);
+    }
+
+    err_t rv = ret ? ERR_OK : ERR_IF;
+    return rv;
 }
 
 void LWIP::Interface::emac_input(emac_mem_buf_t *buf)

connectivity/netsocket/include/netsocket/EMAC.h

@@ -176,6 +176,17 @@ class EMAC {
      * @param mem_mngr Pointer to memory manager
      */
     virtual void set_memory_manager(EMACMemoryManager &mem_mngr) = 0;
+
+    virtual bool is_ready_to_tx() {
+        return true;
+    }
+
+    virtual void restart() {
+    }
+
+    virtual int get_interface_status() {
+        return -1;
+    }
 };
 
 

targets/TARGET_STM/TARGET_STM32H7/STM32Cube_FW/STM32H7xx_HAL_Driver/stm32h7xx_hal_eth.c

@@ -2341,13 +2341,7 @@ HAL_StatusTypeDef HAL_ETH_SetWakeUpFilter(ETH_HandleTypeDef *heth, uint32_t *pFi
   */
 HAL_ETH_StateTypeDef HAL_ETH_GetState(ETH_HandleTypeDef *heth)
 {
-  HAL_ETH_StateTypeDef ret;
-  HAL_ETH_StateTypeDef gstate = heth->gState;
-  HAL_ETH_StateTypeDef rxstate =heth->RxState;
-
-  ret = gstate;
-  ret |= rxstate;
-  return ret;
+  return heth->gState;
 }
 
 /**