Merge pull request arduino#4317 from NicoHood/RecvControlLong

Added Long USB RecvControl call for >64 bytes

Author: facchinm

hardware/arduino/avr/cores/arduino/USBAPI.h

@@ -193,6 +193,7 @@ bool	CDC_Setup(USBSetup& setup);
 
 int USB_SendControl(uint8_t flags, const void* d, int len);
 int USB_RecvControl(void* d, int len);
+int USB_RecvControlLong(void* d, int len);
 
 uint8_t	USB_Available(uint8_t ep);
 uint8_t USB_SendSpace(uint8_t ep);

hardware/arduino/avr/cores/arduino/USBCore.cpp

@@ -426,7 +426,7 @@ static bool USB_SendStringDescriptor(const u8*string_P, u8 string_len, uint8_t f
 
 //	Does not timeout or cross fifo boundaries
 //	Will only work for transfers <= 64 bytes
-//	TODO
+//	Use USB_RecvControlLong for longer transfers
 int USB_RecvControl(void* d, int len)
 {
 	WaitOUT();
@@ -435,6 +435,25 @@ int USB_RecvControl(void* d, int len)
 	return len;
 }
 
+//	Does not timeout or cross fifo boundaries
+int USB_RecvControlLong(void* d, int len)
+{
+	auto bytesleft = len;
+	while(bytesleft > 0)
+	{
+		// Dont receive more than the USB Control EP has to offer
+		// Use fixed 64 because control EP always have 64 bytes even on 16u2.
+		auto recvLength = bytesleft;
+		if(recvLength > 64){
+			recvLength = 64;
+		}
+
+		// Write data to fit to the beginning of the array
+		bytesleft -= USB_RecvControl((u8*)d + len - bytesleft, recvLength);
+	}
+	return len;
+}
+
 static u8 SendInterfaces()
 {
 	u8 interfaces = 0;