Add USB Gadget Device support (#567)

* Initial attempt to include USB Gadget Mode as a configuration option.  Note: Also requires a move to the latest release of circle.

* Set "official" (as allocated from pid.codes) USB vendor and device ID for MiniDexed

USBID.sh

@@ -0,0 +1,2 @@
+USB_VID=0x1209
+USB_DID=0xF043

build.sh

@@ -20,6 +20,15 @@ if [ "${RPI}" -gt "1" ]; then
     OPTIONS="${OPTIONS} -o ARM_ALLOW_MULTI_CORE"
 fi
 
+# USB Vendor and Device ID for use with USB Gadget Mode
+source USBID.sh
+if [ "${USB_VID}" ] ; then
+	OPTIONS="${OPTIONS} -o USB_GADGET_VENDOR_ID=${USB_VID}"
+fi
+if [ "${USB_DID}" ] ; then
+	OPTIONS="${OPTIONS} -o USB_GADGET_DEVICE_ID=${USB_DID}"
+fi
+
 # Build circle-stdlib library
 cd circle-stdlib/
 make mrproper || true

src/Rules.mk

@@ -22,6 +22,7 @@ LIBS += \
 	$(CIRCLEHOME)/addon/Properties/libproperties.a \
 	$(CIRCLEHOME)/addon/SDCard/libsdcard.a \
   	$(CIRCLEHOME)/lib/usb/libusb.a \
+	$(CIRCLEHOME)/lib/usb/gadget/libusbgadget.a \
  	$(CIRCLEHOME)/lib/input/libinput.a \
 	$(CIRCLEHOME)/lib/sound/libsound.a \
  	$(CIRCLEHOME)/addon/fatfs/libfatfs.a \

src/circle_stdlib_app.h

@@ -25,7 +25,6 @@
 #include <circle/writebuffer.h>
 #include <circle/timer.h>
 #include <circle/logger.h>
-#include <circle/usb/usbhcidevice.h>
 #include <SDCard/emmc.h>
 #include <circle/input/console.h>
 #include <circle/sched/scheduler.h>
@@ -160,7 +159,6 @@ class CStdlibAppStdio: public CStdlibAppScreen
                          const char *pPartitionName = CSTDLIBAPP_DEFAULT_PARTITION)
                 : CStdlibAppScreen (kernel),
                   mpPartitionName (pPartitionName),
-                  mUSBHCI (&mInterrupt, &mTimer, TRUE),
                   mEMMC (&mInterrupt, &mTimer, &mActLED),
 #if !defined(__aarch64__) || !defined(LEAVE_QEMU_ON_HALT)
                   //mConsole (&mScreen, TRUE)
@@ -199,16 +197,6 @@ class CStdlibAppStdio: public CStdlibAppScreen
                         return false;
                 }
 
-#if !defined(__aarch64__) || !defined(LEAVE_QEMU_ON_HALT)
-                // The USB driver is not supported under 64-bit QEMU, so
-                // the initialization must be skipped in this case, or an
-                // exit happens here under 64-bit QEMU.
-                if (!mUSBHCI.Initialize ())
-                {
-                        return false;
-                }
-#endif
-
                 if (!mConsole.Initialize ())
                 {
                         return false;
@@ -223,7 +211,7 @@ class CStdlibAppStdio: public CStdlibAppScreen
 
                 return true;
         }
-
+		
         virtual void Cleanup (void)
         {
                 f_mount(0, "", 0);
@@ -232,7 +220,6 @@ class CStdlibAppStdio: public CStdlibAppScreen
         }
 
 protected:
-        CUSBHCIDevice   mUSBHCI;
         CEMMCDevice     mEMMC;
         FATFS           mFileSystem;
         CConsole        mConsole;

src/config.cpp

@@ -35,6 +35,8 @@ CConfig::~CConfig (void)
 void CConfig::Load (void)
 {
 	m_Properties.Load ();
+
+	m_bUSBGadgetMode = m_Properties.GetNumber ("USBGadget", 0) != 0;
 
 	m_SoundDevice = m_Properties.GetString ("SoundDevice", "pwm");
 
@@ -152,6 +154,11 @@ void CConfig::Load (void)
 	m_bPerformanceSelectChannel = m_Properties.GetNumber ("PerformanceSelectChannel", 0);
 }
 
+bool CConfig::GetUSBGadgetMode (void) const
+{
+	return m_bUSBGadgetMode;
+}
+
 const char *CConfig::GetSoundDevice (void) const
 {
 	return m_SoundDevice.c_str ();

src/config.h

@@ -62,6 +62,9 @@ class CConfig		// Configuration for MiniDexed
 	~CConfig (void);
 
 	void Load (void);
+
+	// USB Mode
+	bool GetUSBGadgetMode (void) const;	// true if in USB gadget mode
 
 	// Sound device
 	const char *GetSoundDevice (void) const;
@@ -167,6 +170,8 @@ class CConfig		// Configuration for MiniDexed
 
 private:
 	CPropertiesFatFsFile m_Properties;
+
+	bool m_bUSBGadgetMode;
 
 	std::string m_SoundDevice;
 	unsigned m_nSampleRate;

src/kernel.cpp

@@ -21,6 +21,8 @@
 #include <circle/logger.h>
 #include <circle/synchronize.h>
 #include <assert.h>
+#include <circle/usb/usbhcidevice.h>
+#include <circle/usb/gadget/usbmidigadget.h>
 
 LOGMODULE ("kernel");
 
@@ -63,7 +65,23 @@ bool CKernel::Initialize (void)
 	}
 
 	m_Config.Load ();
+
+	if (m_Config.GetUSBGadgetMode())
+	{
+		// Run the USB stack in USB Gadget (device) mode
+		m_pUSB = new CUSBMIDIGadget (&mInterrupt);
+	}
+	else
+	{
+		// Run the USB stack in USB Host (default) mode
+		m_pUSB = new CUSBHCIDevice (&mInterrupt, &mTimer, TRUE);
+	}
 
+    if (!m_pUSB->Initialize ())
+    {
+		return FALSE;
+    }
+
 	m_pDexed = new CMiniDexed (&m_Config, &mInterrupt, &m_GPIOManager, &m_I2CMaster,
 				   &mFileSystem);
 	assert (m_pDexed);
@@ -82,7 +100,7 @@ CStdlibApp::TShutdownMode CKernel::Run (void)
 
 	while (42 == 42)
 	{
-		boolean bUpdated = mUSBHCI.UpdatePlugAndPlay ();
+		boolean bUpdated = m_pUSB->UpdatePlugAndPlay ();
 
 		m_pDexed->Process(bUpdated);
 

src/kernel.h

@@ -24,6 +24,7 @@
 #include <circle/cputhrottle.h>
 #include <circle/gpiomanager.h>
 #include <circle/i2cmaster.h>
+#include <circle/usb/usbcontroller.h>
 #include "config.h"
 #include "minidexed.h"
 
@@ -54,6 +55,7 @@ class CKernel : public CStdlibAppStdio
 	CGPIOManager	m_GPIOManager;
 	CI2CMaster	m_I2CMaster;
 	CMiniDexed	*m_pDexed;
+	CUSBController *m_pUSB;
 
 	static CKernel *s_pThis;
 };

src/minidexed.cpp

@@ -97,6 +97,15 @@ CMiniDexed::CMiniDexed (CConfig *pConfig, CInterruptSystem *pInterrupt,
 		m_pTG[i]->setEngineType(pConfig->GetEngineType ());
 		m_pTG[i]->activate ();
 	}
+
+	if (pConfig->GetUSBGadgetMode())
+	{
+		LOGNOTE ("USB In Gadget (Device) Mode");
+	}
+	else
+	{
+		LOGNOTE ("USB In Host Mode");
+	}
 
 	for (unsigned i = 0; i < CConfig::MaxUSBMIDIDevices; i++)
 	{

submod.sh

@@ -1,15 +1,24 @@
 #!/bin/bash
 set -ex
+#
+# Update top-level modules as a baseline
 git submodule update --init --recursive
+#
+# Use fixed master branch of circle-stdlib then re-update
 cd circle-stdlib/
-git checkout e318f89 # Needed to support Circle develop?
+git checkout 695ab4a
+git submodule update --init --recursive
 cd -
+#
+# Optional update submodules explicitly
 cd circle-stdlib/libs/circle
-git checkout ec09d7e # develop
+git checkout fe09c4b
 cd -
 cd circle-stdlib/libs/circle-newlib
-git checkout 48bf91d # needed for circle ec09d7e
+#git checkout develop
 cd -
+#
+# Use fixed master branch of Synth_Dexed
 cd Synth_Dexed/
 git checkout c9f5274
 cd -