dwc2/host: attach debouncing fixes

src/portable/synopsys/dwc2/hcd_dwc2.c

@@ -109,6 +109,7 @@ typedef struct {
 typedef struct {
   hcd_xfer_t xfer[DWC2_CHANNEL_COUNT_MAX];
   hcd_endpoint_t edpt[CFG_TUH_DWC2_ENDPOINT_MAX];
+  bool attach_debounce; // if true: wait for the debounce delay before issuing new attach events
 } hcd_data_t;
 
 hcd_data_t _hcd_data;
@@ -413,6 +414,11 @@ uint32_t hcd_frame_number(uint8_t rhport) {
 
 // Get the current connect status of roothub port
 bool hcd_port_connect_status(uint8_t rhport) {
+  // this is called from enum_new_device() - after the debouncing delays
+  if (_hcd_data.attach_debounce) {
+    _hcd_data.attach_debounce = false; // allow new attach events again
+  }
+
   dwc2_regs_t* dwc2 = DWC2_REG(rhport);
   return dwc2->hprt & HPRT_CONN_STATUS;
 }
@@ -1265,9 +1271,10 @@ static void handle_hprt_irq(uint8_t rhport, bool in_isr) {
     hprt |= HPRT_CONN_DETECT;
 
     if (hprt_bm.conn_status) {
-      hcd_event_device_attach(rhport, in_isr);
-    } else {
-      hcd_event_device_remove(rhport, in_isr);
+      if (!_hcd_data.attach_debounce) {
+        _hcd_data.attach_debounce = true; // block new attach events until the debounce delay is over
+        hcd_event_device_attach(rhport, in_isr);
+      }
     }
   }
 
@@ -1330,6 +1337,19 @@ void hcd_int_handler(uint8_t rhport, bool in_isr) {
     handle_channel_irq(rhport, in_isr);
   }
 
+  if (gintsts & GINTSTS_DISCINT) {
+    // Device disconnected
+    dwc2->gintsts = GINTSTS_DISCINT;
+
+    // ignore device removal if attach debounce is active
+    // it will evaluate the port status after the debounce delay
+    if (!_hcd_data.attach_debounce) {
+      if (!(dwc2->hprt & HPRT_CONN_STATUS)) {
+        hcd_event_device_remove(rhport, in_isr);
+      }
+    }
+  }
+
 #if CFG_TUH_DWC2_SLAVE_ENABLE
   // RxFIFO non-empty interrupt handling
   if (gintsts & GINTSTS_RXFLVL) {