usb: add USB mass storage class support

src/machine/machine_rp2040_usb.go

@@ -95,10 +95,9 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 		for i := 0; i < 16; i++ {
 			if s2&(1<<(i*2+1)) > 0 {
 				buf := handleEndpointRx(uint32(i))
-				if usbRxHandler[i] != nil {
-					usbRxHandler[i](buf)
+				if usbRxHandler[i] == nil || usbRxHandler[i](buf) {
+					AckEndpointRxMessage(uint32(i))
 				}
-				handleEndpointRxComplete(uint32(i))
 			}
 		}
 

src/machine/machine_rp2350_usb.go

@@ -98,10 +98,9 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 		for i := 0; i < 16; i++ {
 			if s2&(1<<(i*2+1)) > 0 {
 				buf := handleEndpointRx(uint32(i))
-				if usbRxHandler[i] != nil {
-					usbRxHandler[i](buf)
+				if usbRxHandler[i] == nil || usbRxHandler[i](buf) {
+					AckEndpointRxMessage(uint32(i))
 				}
-				handleEndpointRxComplete(uint32(i))
 			}
 		}
 

src/machine/machine_rp2_usb.go

@@ -115,7 +115,9 @@ func handleEndpointRx(ep uint32) []byte {
 	return _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz]
 }
 
-func handleEndpointRxComplete(ep uint32) {
+// AckEndpointRxMessage is called to acknowledge the completion of a delayed USB OUT transfer.
+func AckEndpointRxMessage(ep uint32) {
+	ep = ep & 0x7F
 	setEPDataPID(ep, !epXdata0[ep])
 }
 
@@ -152,23 +154,25 @@ func sendViaEPIn(ep uint32, data []byte, count int) {
 
 // Set ENDPOINT_HALT/stall status on a USB IN endpoint.
 func (dev *USBDevice) SetStallEPIn(ep uint32) {
+	ep = ep & 0x7F
 	// Prepare buffer control register value
 	if ep == 0 {
 		armEPZeroStall()
 	}
 	val := uint32(usbBuf0CtrlFull)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
+	_usbDPSRAM.EPxBufferControl[ep].In.Set(val)
 	val |= uint32(usbBuf0CtrlStall)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].In.Set(val)
+	_usbDPSRAM.EPxBufferControl[ep].In.Set(val)
 }
 
 // Set ENDPOINT_HALT/stall status on a USB OUT endpoint.
 func (dev *USBDevice) SetStallEPOut(ep uint32) {
+	ep = ep & 0x7F
 	if ep == 0 {
 		panic("SetStallEPOut: EP0 OUT not valid")
 	}
 	val := uint32(usbBuf0CtrlStall)
-	_usbDPSRAM.EPxBufferControl[ep&0x7F].Out.Set(val)
+	_usbDPSRAM.EPxBufferControl[ep].Out.Set(val)
 }
 
 // Clear the ENDPOINT_HALT/stall on a USB IN endpoint.
@@ -178,7 +182,7 @@ func (dev *USBDevice) ClearStallEPIn(ep uint32) {
 	_usbDPSRAM.EPxBufferControl[ep].In.ClearBits(val)
 	if epXPIDReset[ep] {
 		// Reset the PID to DATA0
-		setEPDataPID(ep&0x7F, false)
+		setEPDataPID(ep, false)
 	}
 }
 

src/machine/usb.go

@@ -121,7 +121,7 @@ var usb_trans_buffer [255]uint8
 
 var (
 	usbTxHandler    [usb.NumberOfEndpoints]func()
-	usbRxHandler    [usb.NumberOfEndpoints]func([]byte)
+	usbRxHandler    [usb.NumberOfEndpoints]func([]byte) bool
 	usbSetupHandler [usb.NumberOfInterfaces]func(usb.Setup) bool
 	usbStallHandler [usb.NumberOfEndpoints]func(usb.Setup) bool
 
@@ -134,6 +134,8 @@ var (
 		usb.HID_ENDPOINT_OUT:  (usb.ENDPOINT_TYPE_DISABLE), // Interrupt Out
 		usb.MIDI_ENDPOINT_IN:  (usb.ENDPOINT_TYPE_DISABLE), // Bulk In
 		usb.MIDI_ENDPOINT_OUT: (usb.ENDPOINT_TYPE_DISABLE), // Bulk Out
+		usb.MSC_ENDPOINT_IN:   (usb.ENDPOINT_TYPE_DISABLE), // Bulk In
+		usb.MSC_ENDPOINT_OUT:  (usb.ENDPOINT_TYPE_DISABLE), // Bulk Out
 	}
 )
 
@@ -330,7 +332,12 @@ func ConfigureUSBEndpoint(desc descriptor.Descriptor, epSettings []usb.EndpointC
 		} else {
 			endPoints[ep.Index] = uint32(ep.Type | usb.EndpointOut)
 			if ep.RxHandler != nil {
-				usbRxHandler[ep.Index] = ep.RxHandler
+				usbRxHandler[ep.Index] = func(b []byte) bool {
+					ep.RxHandler(b)
+					return true
+				}
+			} else if ep.DelayRxHandler != nil {
+				usbRxHandler[ep.Index] = ep.DelayRxHandler
 			}
 		}
 		if ep.StallHandler != nil {

src/machine/usb/config.go

@@ -1,12 +1,13 @@
 package usb
 
 type EndpointConfig struct {
-	Index        uint8
-	IsIn         bool
-	TxHandler    func()
-	RxHandler    func([]byte)
-	StallHandler func(Setup) bool
-	Type         uint8
+	Index          uint8
+	IsIn           bool
+	TxHandler      func()
+	RxHandler      func([]byte)
+	DelayRxHandler func([]byte) bool
+	StallHandler   func(Setup) bool
+	Type           uint8
 }
 
 type SetupConfig struct {

src/machine/usb/descriptor/endpoint.go

@@ -4,6 +4,17 @@ import (
 	"internal/binary"
 )
 
+/* Endpoint Descriptor
+USB 2.0 Specification: 9.6.6 Endpoint
+*/
+
+const (
+	TransferTypeControl uint8 = iota
+	TransferTypeIsochronous
+	TransferTypeBulk
+	TransferTypeInterrupt
+)
+
 var endpointEP1IN = [endpointTypeLen]byte{
 	endpointTypeLen,
 	TypeEndpoint,
@@ -74,6 +85,36 @@ var EndpointEP5OUT = EndpointType{
 	data: endpointEP5OUT[:],
 }
 
+// Mass Storage Class bulk in endpoint
+var endpointEP8IN = [endpointTypeLen]byte{
+	endpointTypeLen,
+	TypeEndpoint,
+	0x88,             // EndpointAddress
+	TransferTypeBulk, // Attributes
+	0x40,             // MaxPacketSizeL (64 bytes)
+	0x00,             // MaxPacketSizeH
+	0x00,             // Interval
+}
+
+var EndpointEP8IN = EndpointType{
+	data: endpointEP8IN[:],
+}
+
+// Mass Storage Class bulk out endpoint
+var endpointEP9OUT = [endpointTypeLen]byte{
+	endpointTypeLen,
+	TypeEndpoint,
+	0x09,             // EndpointAddress
+	TransferTypeBulk, // Attributes
+	0x40,             // MaxPacketSizeL (64 bytes)
+	0x00,             // MaxPacketSizeH
+	0x00,             // Interval
+}
+
+var EndpointEP9OUT = EndpointType{
+	data: endpointEP9OUT[:],
+}
+
 const (
 	endpointTypeLen = 7
 )
@@ -109,3 +150,7 @@ func (d EndpointType) MaxPacketSize(v uint16) {
 func (d EndpointType) Interval(v uint8) {
 	d.data[6] = byte(v)
 }
+
+func (d EndpointType) GetMaxPacketSize() uint16 {
+	return binary.LittleEndian.Uint16(d.data[4:6])
+}

src/machine/usb/descriptor/msc.go

@@ -0,0 +1,75 @@
+package descriptor
+
+const (
+	interfaceClassMSC = 0x08
+	mscSubclassSCSI   = 0x06
+	mscProtocolBOT    = 0x50
+)
+
+var interfaceAssociationMSC = [interfaceAssociationTypeLen]byte{
+	interfaceAssociationTypeLen,
+	TypeInterfaceAssociation,
+	0x02,              // FirstInterface
+	0x01,              // InterfaceCount
+	interfaceClassMSC, // FunctionClass
+	mscSubclassSCSI,   // FunctionSubClass
+	mscProtocolBOT,    // FunctionProtocol
+	0x00,              // Function
+}
+
+var InterfaceAssociationMSC = InterfaceAssociationType{
+	data: interfaceAssociationMSC[:],
+}
+
+var interfaceMSC = [interfaceTypeLen]byte{
+	interfaceTypeLen,  // Length
+	TypeInterface,     // DescriptorType
+	0x02,              // InterfaceNumber
+	0x00,              // AlternateSetting
+	0x02,              // NumEndpoints
+	interfaceClassMSC, // InterfaceClass (Mass Storage)
+	mscSubclassSCSI,   // InterfaceSubClass (SCSI Transparent)
+	mscProtocolBOT,    // InterfaceProtocol (Bulk-Only Transport)
+	0x00,              // Interface
+}
+
+var InterfaceMSC = InterfaceType{
+	data: interfaceMSC[:],
+}
+
+var configurationMSC = [configurationTypeLen]byte{
+	configurationTypeLen,
+	TypeConfiguration,
+	0x6a, 0x00, // wTotalLength
+	0x03, // number of interfaces (bNumInterfaces)
+	0x01, // configuration value (bConfigurationValue)
+	0x00, // index to string description (iConfiguration)
+	0xa0, // attributes (bmAttributes)
+	0x32, // maxpower (100 mA) (bMaxPower)
+}
+
+var ConfigurationMSC = ConfigurationType{
+	data: configurationMSC[:],
+}
+
+// Mass Storage Class
+var MSC = Descriptor{
+	Device: DeviceCDC.Bytes(),
+	Configuration: Append([][]byte{
+		ConfigurationMSC.Bytes(),
+		InterfaceAssociationCDC.Bytes(),
+		InterfaceCDCControl.Bytes(),
+		ClassSpecificCDCHeader.Bytes(),
+		ClassSpecificCDCACM.Bytes(),
+		ClassSpecificCDCUnion.Bytes(),
+		ClassSpecificCDCCallManagement.Bytes(),
+		EndpointEP1IN.Bytes(),
+		InterfaceCDCData.Bytes(),
+		EndpointEP2OUT.Bytes(),
+		EndpointEP3IN.Bytes(),
+		InterfaceAssociationMSC.Bytes(),
+		InterfaceMSC.Bytes(),
+		EndpointEP8IN.Bytes(),
+		EndpointEP9OUT.Bytes(),
+	}),
+}

src/machine/usb/msc/cbw.go

@@ -0,0 +1,62 @@
+package msc
+
+import (
+	"encoding/binary"
+	"machine/usb/msc/csw"
+	"machine/usb/msc/scsi"
+)
+
+const (
+	cbwMsgLen = 31         // Command Block Wrapper (CBW) message length
+	Signature = 0x43425355 // "USBC" in little endian
+)
+
+type CBW struct {
+	HasCmd bool
+	Data   []byte
+}
+
+func (c *CBW) Tag() uint32 {
+	return binary.LittleEndian.Uint32(c.Data[4:8])
+}
+
+func (c *CBW) length() int {
+	return len(c.Data)
+}
+
+func (c *CBW) validLength() bool {
+	return len(c.Data) == cbwMsgLen
+}
+
+func (c *CBW) validSignature() bool {
+	return binary.LittleEndian.Uint32(c.Data[:4]) == Signature
+}
+
+func (c *CBW) SCSICmd() scsi.Cmd {
+	return scsi.Cmd{Data: c.Data[15:]}
+}
+
+func (c *CBW) transferLength() uint32 {
+	return binary.LittleEndian.Uint32(c.Data[8:12])
+}
+
+// isIn returns true if the command direction is from the device to the host.
+func (c *CBW) isIn() bool {
+	return c.Data[12]>>7 != 0
+}
+
+// isOut returns true if the command direction is from the host to the device.
+func (c *CBW) isOut() bool {
+	return !c.isIn()
+}
+
+func (c *CBW) CSW(status csw.Status, residue uint32, b []byte) {
+	// Signature: "USBS" 53425355h (little endian)
+	binary.LittleEndian.PutUint32(b[:4], csw.Signature)
+	// Tag: (same as CBW)
+	copy(b[4:8], c.Data[4:8])
+	// Data Residue: (untransferred bytes)
+	binary.LittleEndian.PutUint32(b[8:12], residue)
+	// Status:
+	b[12] = byte(status)
+}

src/machine/usb/msc/csw/csw.go

@@ -0,0 +1,14 @@
+package csw
+
+type Status uint8
+
+const (
+	StatusPassed Status = iota
+	StatusFailed
+	StatusPhaseError
+)
+
+const (
+	MsgLen    = 13
+	Signature = 0x53425355 // "USBS" in little endian
+)