Queue Notification when setting, not waiting for the callback. #491

Author: SmittyHalibut

src/arduino/Adafruit_USBD_CDC.cpp

@@ -174,10 +174,6 @@ bool Adafruit_USBD_CDC::rts(void) {
   return tud_cdc_n_get_line_state(_instance) & CDC_CONTROL_LINE_STATE_RTS;
 }
 
-bool Adafruit_USBD_CDC::cts(void) {
-  return tud_cdc_n_get_serial_state(_instance).cts;
-}
-
 bool Adafruit_USBD_CDC::dsr(void) {
   return tud_cdc_n_get_serial_state(_instance).dsr;
 }
@@ -190,12 +186,6 @@ bool Adafruit_USBD_CDC::ri(void) {
   return tud_cdc_n_get_serial_state(_instance).ri;
 }
 
-void Adafruit_USBD_CDC::cts(bool c) {
-  cdc_serial_state_t serial_state = tud_cdc_n_get_serial_state(_instance);
-  serial_state.cts = c;
-  tud_cdc_n_set_serial_state(_instance, serial_state);
-}
-
 void Adafruit_USBD_CDC::dsr(bool c) {
   cdc_serial_state_t serial_state = tud_cdc_n_get_serial_state(_instance);
   serial_state.dsr = c;

src/arduino/Adafruit_USBD_CDC.h

@@ -63,16 +63,17 @@ class Adafruit_USBD_CDC : public Stream, public Adafruit_USBD_Interface {
   // Flow control bit getters.
   int dtr(void); // pre-existing, I don't want to change the return type.
   bool rts(void);
-  bool cts(void);
+  // bool cts(void);  // NOT PART OF THE CDC ACM SPEC?!
   bool dsr(void);
   bool dcd(void);
   bool ri(void);
 
   // Flow control bit setters.
-  void cts(bool c);
+  // void cts(bool c);  // NOT PART OF CDC ACM SPEC?!
   void dsr(bool c);
   void dcd(bool c);
   void ri(bool c);
+  // Break is a little harder, it's an event, not a state.
 
   // Stream API
   virtual int available(void);

src/class/cdc/cdc.h

@@ -416,21 +416,22 @@ TU_VERIFY_STATIC(sizeof(cdc_line_control_state_t) == 2, "size is not correct");
 // Notifications
 //--------------------------------------------------------------------+
 
-typedef struct TU_ATTR_PACKED {
-  uint16_t dcd         :1;
-  uint16_t dsr         :1;
-  uint16_t break_err   :1;
-  uint16_t ri          :1;
-  uint16_t frame_err   :1;
-  uint16_t parity_err  :1;
-  uint16_t overrun_err :1;
-  uint16_t cts         :1;  // https://community.st.com/t5/stm32-mcus-products/cts-signal-on-usb-cdc/td-p/325800
-  uint16_t             :8;
+typedef union TU_ATTR_PACKED {
+  struct {
+    uint16_t dcd         :1;
+    uint16_t dsr         :1;
+    uint16_t break_err   :1;
+    uint16_t ri          :1;
+    uint16_t frame_err   :1;
+    uint16_t parity_err  :1;
+    uint16_t overrun_err :1;
+    uint16_t             :9;
+  };
+  uint16_t state;
 } cdc_serial_state_t;
 
 TU_VERIFY_STATIC(sizeof(cdc_serial_state_t) == 2, "size is not correct");
 
-// Add more notifications here.  PSTN120.pdf, Section 6.5
 typedef struct TU_ATTR_PACKED {
   tusb_notification_t header;
   union {

src/class/cdc/cdc_device.c

@@ -59,7 +59,7 @@ typedef struct {
   // Bit 0:  DTR (Data Terminal Ready), Bit 1: RTS (Request to Send)
   uint8_t line_state;
 
-  // Notify host of flow control bits: CTS, DSR, DCD, RI, and some error flags.
+  // Notify host of flow control bits: DSR, DCD, RI, and some error flags.
   cdc_serial_state_t serial_state;
   bool serial_state_changed;
 
@@ -120,6 +120,29 @@ static bool _prep_out_transaction (cdcd_interface_t* p_cdc) {
   }
 }
 
+bool _send_serial_state_notification(cdcd_interface_t *p_cdc) {
+  const uint8_t rhport = 0;
+
+  if (!p_cdc->serial_state_changed) {
+    // Nothing to do.
+    return true;
+  }
+
+  if (!usbd_edpt_claim(rhport, p_cdc->ep_notif)) {
+    // If claim failed, we're already in the middle of a transaction.
+    // cdcd_xfer_cb() will pick up this change.
+    return true;
+  }
+  
+  // We have the end point.  Build and send the notification.
+  p_cdc->serial_state_changed = false;
+  
+  p_cdc->epnotif_buf = cdc_notify_serial_status;
+  p_cdc->epnotif_buf.header.wIndex = p_cdc->itf_num;
+  p_cdc->epnotif_buf.serial_state = p_cdc->serial_state;
+  return usbd_edpt_xfer(rhport, p_cdc->ep_notif, (uint8_t *) &(p_cdc->epnotif_buf), sizeof(p_cdc->epnotif_buf));
+}
+
 //--------------------------------------------------------------------+
 // APPLICATION API
 //--------------------------------------------------------------------+
@@ -148,11 +171,12 @@ cdc_serial_state_t tud_cdc_n_get_serial_state(uint8_t itf) {
 }
 
 void tud_cdc_n_set_serial_state(uint8_t itf, cdc_serial_state_t serial_state) {
-  if (memcmp(&(_cdcd_itf[itf].serial_state), &serial_state, sizeof(serial_state)) != 0) {
-    TU_LOG_DRV("  Serial State Changed: %x -> %x\r\n", _cdcd_itf[itf].serial_state, serial_state);
-    _cdcd_itf[itf].serial_state_changed = true;
+  cdcd_interface_t* p_cdc = &_cdcd_itf[itf];
+  if (p_cdc->serial_state.state != serial_state.state) {
+    p_cdc->serial_state_changed = true;
+    p_cdc->serial_state = serial_state;
+    _send_serial_state_notification(p_cdc);
   }
-  _cdcd_itf[itf].serial_state = serial_state;
 }
 
 void tud_cdc_n_get_line_coding(uint8_t itf, cdc_line_coding_t* coding) {
@@ -343,13 +367,10 @@ uint16_t cdcd_open(uint8_t rhport, tusb_desc_interface_t const * itf_desc, uint1
 
   if (TUSB_DESC_ENDPOINT == tu_desc_type(p_desc)) {
     // notification endpoint
-    tusb_desc_endpoint_t desc_ep = *(tusb_desc_endpoint_t const*) p_desc;
-    TU_LOG_DRV("  Interval before: %d\r\n", desc_ep.bInterval);
-
-    desc_ep.bInterval = 1;  // Query every frame, 1ms at Full Speed.
+    tusb_desc_endpoint_t const* desc_ep = (tusb_desc_endpoint_t const*) p_desc;
 
-    TU_ASSERT(usbd_edpt_open(rhport, &desc_ep), 0);
-    p_cdc->ep_notif = desc_ep.bEndpointAddress;
+    TU_ASSERT(usbd_edpt_open(rhport, desc_ep), 0);
+    p_cdc->ep_notif = desc_ep->bEndpointAddress;
 
     drv_len += tu_desc_len(p_desc);
     p_desc = tu_desc_next(p_desc);
@@ -460,10 +481,9 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
     if ((ep_addr == p_cdc->ep_out) || (ep_addr == p_cdc->ep_in) || (ep_addr == p_cdc->ep_notif)) break;
   }
   TU_ASSERT(itf < CFG_TUD_CDC);
-
+  
   // Received new data
   if (ep_addr == p_cdc->ep_out) {
-    TU_LOG_DRV("  XFer Out\r\n");
     tu_fifo_write_n(&p_cdc->rx_ff, p_cdc->epout_buf, (uint16_t) xferred_bytes);
 
     // Check for wanted char and invoke callback if needed
@@ -486,7 +506,6 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
   // Note: This will cause incorrect baudrate set in line coding.
   //       Though maybe the baudrate is not really important !!!
   if (ep_addr == p_cdc->ep_in) {
-    TU_LOG_DRV("  XFer In\r\n");
     // invoke transmit callback to possibly refill tx fifo
     if (tud_cdc_tx_complete_cb) tud_cdc_tx_complete_cb(itf);
 
@@ -503,27 +522,8 @@ bool cdcd_xfer_cb(uint8_t rhport, uint8_t ep_addr, xfer_result_t result, uint32_
 
   // Notifications
   if (ep_addr == p_cdc->ep_notif) {
-    TU_LOG_DRV("  XFer Notification\r\n");
-    uint8_t const rhport = 0;
-
-    // SERIAL_STATE notification. Send flow control signals.
-    if (p_cdc->serial_state_changed) {
-      p_cdc->serial_state_changed = false;
-
-      // Build the notification
-      p_cdc->epnotif_buf = cdc_notify_serial_status;
-      p_cdc->epnotif_buf.header.wIndex = p_cdc->itf_num;
-      p_cdc->epnotif_buf.serial_state = p_cdc->serial_state;
-
-      // claim endpoint
-      TU_VERIFY(usbd_edpt_claim(rhport, p_cdc->ep_notif), 0);
-
-      // Send notification
-      return usbd_edpt_xfer(rhport, p_cdc->ep_notif, (uint8_t *) &(p_cdc->epnotif_buf), sizeof(p_cdc->epnotif_buf));
-    }
-    else {
-      // Send a NAK?
-    }
+    // Send any changes that may have come in while sending the previous change.
+    return _send_serial_state_notification(p_cdc);
   }
 
   return true;

src/class/cdc/cdc_device.h

@@ -143,7 +143,7 @@ TU_ATTR_ALWAYS_INLINE static inline cdc_serial_state_t tud_cdc_get_serial_state(
 }
 
 TU_ATTR_ALWAYS_INLINE static inline void tud_cdc_set_serial_state(cdc_serial_state_t ser_state) {
-  return tud_cdc_n_set_serial_state(0, ser_state);
+  tud_cdc_n_set_serial_state(0, ser_state);
 }
 
 TU_ATTR_ALWAYS_INLINE static inline void tud_cdc_get_line_coding(cdc_line_coding_t* coding) {