USB MIDI for Arduino

hardware/arduino/sam/cores/arduino/USB/Midi.cpp

@@ -0,0 +1,183 @@
+// Copyright (c) 2015, Gary Grewal
+/*
+** Permission to use, copy, modify, and/or distribute this software for
+** any purpose with or without fee is hereby granted, provided that the
+** above copyright notice and this permission notice appear in all copies.
+**
+** THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+** WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
+** WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
+** BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
+** OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+** WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
+** ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
+** SOFTWARE.
+*/
+#include "Arduino.h"
+#include "USBAPI.h"
+#include "Reset.h"
+
+#ifdef MIDI_ENABLED
+
+#define MIDI_BUFFER_SIZE	128
+
+struct ring_bufferMIDI
+{
+	midiEventPacket_t midiEvent[MIDI_BUFFER_SIZE];
+	volatile uint32_t head;
+	volatile uint32_t tail;
+};
+
+ring_bufferMIDI midi_rx_buffer = {{0,0,0,0 }, 0, 0};
+
+_Pragma("pack(1)")
+static const MIDIDescriptor _midiInterface =
+{
+#ifdef CDC_ENABLED
+	D_IAD(MIDI_AC_INTERFACE,MIDI_INTERFACE_COUNT, MIDI_AUDIO, MIDI_AUDIO_CONTROL, 0),
+#endif
+	D_INTERFACE(MIDI_AC_INTERFACE,0,MIDI_AUDIO,MIDI_AUDIO_CONTROL,0),
+	D_AC_INTERFACE(0x1, MIDI_INTERFACE),
+	D_INTERFACE(MIDI_INTERFACE,2, MIDI_AUDIO,MIDI_STREAMING,0),
+	D_AS_INTERFACE,
+	D_MIDI_INJACK(MIDI_JACK_EMD, 0x1),
+	D_MIDI_INJACK(MIDI_JACK_EXT, 0x2),
+	D_MIDI_OUTJACK(MIDI_JACK_EMD, 0x3, 1, 2, 1),
+	D_MIDI_OUTJACK(MIDI_JACK_EXT, 0x4, 1, 1, 1),
+	D_MIDI_JACK_EP(USB_ENDPOINT_OUT(MIDI_ENDPOINT_OUT),USB_ENDPOINT_TYPE_BULK,0x0040),
+	D_MIDI_AC_JACK_EP(1, 1),
+	D_MIDI_JACK_EP(USB_ENDPOINT_IN(MIDI_ENDPOINT_IN),USB_ENDPOINT_TYPE_BULK,0x0040),
+	D_MIDI_AC_JACK_EP (1, 3)
+};
+_Pragma("pack()")
+
+int WEAK MIDI_GetInterface(uint8_t* interfaceNum)
+{
+	interfaceNum[0] += 2;	// uses 2
+	return USBD_SendControl(0,&_midiInterface,sizeof(_midiInterface));
+}
+bool WEAK MIDI_Setup(Setup& setup)
+{
+	//Support requests here if needed. Typically these are optional
+	return false;
+}
+
+void MIDI_::begin()
+{
+	//Nothing to do
+}
+
+void MIDI_::accept(void)
+{
+	static uint32_t mguard = 0;
+
+	// synchronized access to guard
+	do {
+		if (__LDREXW(&mguard) != 0) {
+			__CLREX();
+			return;  // busy
+		}
+	} while (__STREXW(1, &mguard) != 0); // retry until write succeed
+
+	ring_bufferMIDI *buffer = &midi_rx_buffer;
+	uint32_t i = (uint32_t)(buffer->head+1) % MIDI_BUFFER_SIZE;
+
+	// 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.
+	while (i != buffer->tail) {
+		int c;
+		midiEventPacket_t event;
+		if (!USBD_Available(MIDI_RX)) {
+			udd_ack_fifocon(MIDI_RX);
+			break;
+		}
+		c = USBD_Recv(MIDI_RX, &event, sizeof(event) );
+
+		//MIDI paacket has to be 4 bytes
+		if(c < 4)
+			return;
+		buffer->midiEvent[buffer->head] = event;
+		buffer->head = i;
+
+		i = (i + 1) % MIDI_BUFFER_SIZE;
+	}
+
+	// release the guard
+	mguard = 0;
+}
+
+uint32_t MIDI_::available(void)
+{
+
+	ring_bufferMIDI *buffer = &midi_rx_buffer;
+	return (uint32_t)(MIDI_BUFFER_SIZE + buffer->head - buffer->tail) % MIDI_BUFFER_SIZE;
+}
+
+
+midiEventPacket_t MIDI_::read(void)
+{
+	ring_bufferMIDI *buffer = &midi_rx_buffer;
+	midiEventPacket_t c = buffer->midiEvent[buffer->tail];
+	c.header = 0;
+	c.byte1 = 0;
+	c.byte2 = 0;
+	c.byte3 = 0;
+
+	// if the head isn't ahead of the tail, we don't have any characters
+	if (buffer->head == buffer->tail)
+	{
+		return c;
+	}
+	else
+	{
+		midiEventPacket_t c = buffer->midiEvent[buffer->tail];
+		buffer->tail = (uint32_t)(buffer->tail + 1) % MIDI_BUFFER_SIZE;
+		if (USBD_Available(MIDI_RX))
+			accept();
+		return c;
+	}
+}
+
+void MIDI_::flush(void)
+{
+	USBD_Flush(MIDI_TX);
+}
+
+size_t MIDI_::write(const uint8_t *buffer, size_t size)
+{
+	/* only try to send bytes if the high-level MIDI connection itself
+	 is open (not just the pipe) - the OS should set lineState when the port
+	 is opened and clear lineState when the port is closed.
+	 bytes sent before the user opens the connection or after
+	 the connection is closed are lost - just like with a UART. */
+
+	// TODO - ZE - check behavior on different OSes and test what happens if an
+	// open connection isn't broken cleanly (cable is yanked out, host dies
+	// or locks up, or host virtual serial port hangs)
+
+	int r = USBD_Send(MIDI_TX, buffer, size);
+
+	if (r > 0)
+	{
+		return r;
+	} else
+	{
+		return 0;
+	}
+	return 0;
+}
+
+void MIDI_::sendMIDI(midiEventPacket_t event)
+{
+	uint8_t data[4];
+	data[0] = event.header;
+	data[1] = event.byte1;
+	data[2] = event.byte2;
+	data[3] = event.byte3;
+	write(data, 4);
+}
+
+MIDI_ MidiUSB;
+#endif

hardware/arduino/sam/cores/arduino/USB/USBAPI.h

@@ -64,6 +64,37 @@ class Serial_ : public Stream
 };
 extern Serial_ SerialUSB;
 
+
+//Gurbrinder: Midi Interface
+//================================================================================
+//================================================================================
+//	MIDI USB class 
+
+typedef struct 
+{
+	uint8_t header;
+	uint8_t byte1;
+	uint8_t byte2;
+	uint8_t byte3;
+}midiEventPacket_t;
+
+class MIDI_
+{
+private:
+	RingBuffer *_midi_rx_buffer;
+public:
+	void begin();
+
+	virtual uint32_t available(void);
+	virtual void accept(void);
+	virtual midiEventPacket_t read(void);
+	virtual void flush(void);
+	virtual void sendMIDI(midiEventPacket_t event);
+	virtual size_t write(const uint8_t *buffer, size_t size);
+	operator bool();
+};
+extern MIDI_ MidiUSB;
+
 //================================================================================
 //================================================================================
 //	Mouse
@@ -196,6 +227,15 @@ int		CDC_GetOtherInterface(uint8_t* interfaceNum);
 int		CDC_GetDescriptor(int i);
 bool	CDC_Setup(Setup& setup);
 
+//================================================================================
+//================================================================================
+//	MIDI 'Driver'
+
+int		MIDI_GetInterface(uint8_t* interfaceNum);
+int		MIDI_GetOtherInterface(uint8_t* interfaceNum);
+int		MIDI_GetDescriptor(int i);
+bool	MIDI_Setup(Setup& setup);
+
 //================================================================================
 //================================================================================