usb: add USB mass storage class support

Author: mikesmitty

src/machine/usb.go

@@ -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
 	}
 )
 

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 +1,57 @@
+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 {
+	Data []byte
+}
+
+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
+)

src/machine/usb/msc/disk.go

@@ -0,0 +1,73 @@
+package msc
+
+import (
+	"encoding/binary"
+	"machine"
+)
+
+var _ machine.BlockDevice = (*DefaultDisk)(nil)
+
+// DefaultDisk is a placeholder disk implementation
+type DefaultDisk struct {
+}
+
+// NewDefaultDisk creates a new DefaultDisk instance
+func NewDefaultDisk() *DefaultDisk {
+	return &DefaultDisk{}
+}
+
+func (d *DefaultDisk) Size() int64 {
+	return 4096 * int64(d.WriteBlockSize()) // 2MB
+}
+
+func (d *DefaultDisk) WriteBlockSize() int64 {
+	return 512 // 512 bytes
+}
+
+func (d *DefaultDisk) EraseBlockSize() int64 {
+	return 2048 // 4 blocks of 512 bytes
+}
+
+func (d *DefaultDisk) EraseBlocks(startBlock, numBlocks int64) error {
+	return nil
+}
+
+func (d *DefaultDisk) ReadAt(buffer []byte, offset int64) (int, error) {
+	n := uint8(offset)
+	for i := range buffer {
+		n++
+		buffer[i] = n
+	}
+	return len(buffer), nil
+}
+
+func (d *DefaultDisk) WriteAt(buffer []byte, offset int64) (int, error) {
+	return len(buffer), nil
+}
+
+// RegisterBlockDevice registers a BlockDevice provider with the MSC driver
+func (m *msc) RegisterBlockDevice(dev machine.BlockDevice) {
+	m.dev = dev
+
+	// Set VPD UNMAP fields
+	for i := range vpdPages {
+		if vpdPages[i].PageCode == 0xb0 {
+			// 0xb0 - 5.4.5 Block Limits VPD page (B0h)
+			if len(vpdPages[i].Data) >= 28 {
+				// Set the OPTIMAL UNMAP GRANULARITY (write blocks per erase block)
+				granularity := uint32(dev.EraseBlockSize()) / uint32(dev.WriteBlockSize())
+				binary.BigEndian.PutUint32(vpdPages[i].Data[24:28], granularity)
+			}
+			/* TODO: Add method for working out the optimal unmap granularity alignment
+			if len(vpdPages[i].Data) >= 32 {
+				// Set the UNMAP GRANULARITY ALIGNMENT (first sector of first full erase block)
+				// The unmap granularity alignment is used to calculate an optimal unmap request starting LBA as follows:
+				// optimal unmap request starting LBA = (n * OPTIMAL UNMAP GRANULARITY) + UNMAP GRANULARITY ALIGNMENT
+				// where n is zero or any positive integer value
+				// https://www.seagate.com/files/staticfiles/support/docs/manual/Interface%20manuals/100293068j.pdf
+			}
+			*/
+			break
+		}
+	}
+}