USB-CDC: Refactored EP OUT handling

Author: cmaglie

cores/arduino/USB/CDC.cpp

@@ -161,32 +161,21 @@ void Serial_::end(void)
 {
 }
 
-void Serial_::accept(void)
+void Serial_::accept(uint8_t *data, uint32_t size)
 {
-	uint8_t buffer[CDC_SERIAL_BUFFER_SIZE];
-	uint32_t len = usb.recv(CDC_ENDPOINT_OUT, &buffer, CDC_SERIAL_BUFFER_SIZE);
-
-	uint8_t enableInterrupts = ((__get_PRIMASK() & 0x1) == 0);
-	__disable_irq();
-
 	ring_buffer *ringBuffer = &cdc_rx_buffer;
 	uint32_t i = ringBuffer->head;
-
-	// if we should be storing the received character into the location
-	// just before the tail (meaning that the head would advance to the
-	// current location of the tail), we're about to overflow the buffer
-	// and so we don't write the character or advance the head.
-	uint32_t k = 0;
-	while (len > 0 && !ringBuffer->full) {
-		len--;
-		ringBuffer->buffer[i++] = buffer[k++];
+	while (size--) {
+		ringBuffer->buffer[i++] = *data;
+		data++;
 		i %= CDC_SERIAL_BUFFER_SIZE;
-		if (i == ringBuffer->tail)
-			ringBuffer->full = true;
 	}
 	ringBuffer->head = i;
-	if (enableInterrupts) {
-		__enable_irq();
+	if (i == ringBuffer->tail) ringBuffer->full = true;
+	if (availableForStore() < EPX_SIZE) {
+		stalled = true;
+	} else {
+		usb.epOut(CDC_ENDPOINT_OUT);
 	}
 }
 
@@ -196,9 +185,6 @@ int Serial_::available(void)
 	if (buffer->full) {
 		return CDC_SERIAL_BUFFER_SIZE;
 	}
-	if (buffer->head == buffer->tail) {
-		USB->DEVICE.DeviceEndpoint[CDC_ENDPOINT_OUT].EPINTENSET.reg = USB_DEVICE_EPINTENCLR_TRCPT(1);
-	}
 	return (uint32_t)(CDC_SERIAL_BUFFER_SIZE + buffer->head - buffer->tail) % CDC_SERIAL_BUFFER_SIZE;
 }
 
@@ -228,11 +214,11 @@ int Serial_::read(void)
 {
 	ring_buffer *buffer = &cdc_rx_buffer;
 
-	// if the head isn't ahead of the tail, we don't have any characters
-	if (buffer->head == buffer->tail && !buffer->full)
+	// if we have enough space enable OUT endpoint to receive more data
+	if (stalled && availableForStore() >= EPX_SIZE)
 	{
-		if (usb.available(CDC_ENDPOINT_OUT))
-			accept();
+		stalled = false;
+		usb.epOut(CDC_ENDPOINT_OUT);
 	}
 	if (buffer->head == buffer->tail && !buffer->full)
 	{

cores/arduino/USB/USBAPI.h

@@ -92,6 +92,7 @@ class USBDeviceClass {
 	uint32_t available(uint32_t ep);
 	void flush(uint32_t ep);
 	void stall(uint32_t ep);
+	void epOut(uint32_t ep);
 
 	// private?
 	uint32_t armSend(uint32_t ep, const void *data, uint32_t len);
@@ -112,14 +113,14 @@ extern USBDeviceClass USBDevice;
 class Serial_ : public Stream
 {
 public:
-	Serial_(USBDeviceClass &_usb) : usb(_usb) { }
+	Serial_(USBDeviceClass &_usb) : usb(_usb), stalled(false) { }
 	void begin(uint32_t baud_count);
 	void begin(unsigned long, uint8_t);
 	void end(void);
 
 	virtual int available(void);
 	virtual int availableForWrite(void);
-	virtual void accept(void);
+	virtual void accept(uint8_t *data, uint32_t size);
 	virtual int peek(void);
 	virtual int read(void);
 	virtual void flush(void);
@@ -172,6 +173,7 @@ class Serial_ : public Stream
 
 	USBDeviceClass &usb;
 	RingBuffer *_cdc_rx_buffer;
+	bool stalled;
 };
 extern Serial_ SerialUSB;
 

cores/arduino/USB/USBCore.cpp

@@ -247,15 +247,23 @@ bool USBDeviceClass::sendDescriptor(USBSetup &setup)
 	return true;
 }
 
+void USBDeviceClass::epOut(uint32_t ep)
+{
+	usbd.epBank0AckTransferComplete(ep);
+	//usbd.epBank0AckTransferFailed(ep);
+	usbd.epBank0EnableTransferComplete(ep);
+	usbd.epBank0ResetReady(ep);
+}
 
 void USBDeviceClass::handleEndpoint(uint8_t ep)
 {
 #if defined(CDC_ENABLED)
-	if (ep == CDC_ENDPOINT_OUT)
+	if (ep == CDC_ENDPOINT_OUT && usbd.epBank0IsTransferComplete(CDC_ENDPOINT_OUT))
 	{
-		// Handle received bytes
-		if (available(CDC_ENDPOINT_OUT))
-			SerialUSB.accept();
+		// Ack Transfer complete
+		usbd.epBank0AckTransferComplete(CDC_ENDPOINT_OUT);
+
+		SerialUSB.accept(udd_ep_out_cache_buffer[CDC_ENDPOINT_OUT], available(CDC_ENDPOINT_OUT));
 	}
 	if (ep == CDC_ENDPOINT_IN)
 	{
@@ -438,6 +446,7 @@ void USBDeviceClass::initEP(uint32_t ep, uint32_t config)
 		// Release OUT EP
 		usbd.epBank0SetMultiPacketSize(ep, 64);
 		usbd.epBank0SetByteCount(ep, 0);
+		epOut(ep);
 	}
 	else if (config == (USB_ENDPOINT_TYPE_BULK | USB_ENDPOINT_IN(0)))
 	{