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refactor(usb): dynamic endpoint descriptor generation #5405

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7c20bfb
refactor(usb): dynamic endpoint descriptor generation
digitalentity May 17, 2026
3fa3779
Fix the size test.
digitalentity May 17, 2026
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9 changes: 6 additions & 3 deletions src/machine/usb/descriptor/cdc.go
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Original file line number Diff line number Diff line change
Expand Up @@ -150,6 +150,9 @@ var InterfaceCDCData = InterfaceType{
data: interfaceCDCData[:],
}

// EP1 IN : CDC Call Management
// EP2 OUT: CDC OUT
// EP2 IN : CDC IN
var CDC = Descriptor{
Device: DeviceCDC.Bytes(),
Configuration: Append([][]byte{
Expand All @@ -160,9 +163,9 @@ var CDC = Descriptor{
ClassSpecificCDCCallManagement.Bytes(),
ClassSpecificCDCACM.Bytes(),
ClassSpecificCDCUnion.Bytes(),
EndpointEP1IN.Bytes(),
EndpointIN(EndpointEP1, TransferTypeInterrupt, 0x10, 0x10).Bytes(),
InterfaceCDCData.Bytes(),
EndpointEP2OUT.Bytes(),
EndpointEP3IN.Bytes(),
EndpointOUT(EndpointEP2, TransferTypeBulk, 0x40, 0x00).Bytes(),
EndpointIN(EndpointEP3, TransferTypeBulk, 0x40, 0x00).Bytes(),
}),
}
128 changes: 34 additions & 94 deletions src/machine/usb/descriptor/endpoint.go
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Original file line number Diff line number Diff line change
Expand Up @@ -15,104 +15,44 @@ const (
TransferTypeInterrupt
)

var endpointEP1IN = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x81, // EndpointAddress
0x03, // Attributes
0x10, // MaxPacketSizeL
0x00, // MaxPacketSizeH
0x10, // Interval
}

var EndpointEP1IN = EndpointType{
data: endpointEP1IN[:],
}

var endpointEP2OUT = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x02, // EndpointAddress
0x02, // Attributes
0x40, // MaxPacketSizeL
0x00, // MaxPacketSizeH
0x00, // Interval
}

var EndpointEP2OUT = EndpointType{
data: endpointEP2OUT[:],
}
type EndpointNumber uint8

var endpointEP3IN = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x83, // EndpointAddress
0x02, // Attributes
0x40, // MaxPacketSizeL
0x00, // MaxPacketSizeH
0x00, // Interval
}

var EndpointEP3IN = EndpointType{
data: endpointEP3IN[:],
}

var endpointEP4IN = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x84, // EndpointAddress
0x03, // Attributes
0x40, // MaxPacketSizeL
0x00, // MaxPacketSizeH
0x01, // Interval
}

var EndpointEP4IN = EndpointType{
data: endpointEP4IN[:],
}

var endpointEP5OUT = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x05, // EndpointAddress
0x03, // Attributes
0x40, // MaxPacketSizeL
0x00, // MaxPacketSizeH
0x01, // Interval
}

var EndpointEP5OUT = EndpointType{
data: endpointEP5OUT[:],
}

// Mass Storage Class bulk in endpoint
var endpointMSCIN = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x86, // EndpointAddress
TransferTypeBulk, // Attributes
0x40, // MaxPacketSizeL (64 bytes)
0x00, // MaxPacketSizeH
0x00, // Interval
}
const (
EndpointEP1 EndpointNumber = iota
EndpointEP2
EndpointEP3
EndpointEP4
)

var EndpointMSCIN = EndpointType{
data: endpointMSCIN[:],
}
const (
maxEndpoints = 4
)

// Mass Storage Class bulk out endpoint
var endpointMSCOUT = [endpointTypeLen]byte{
endpointTypeLen,
TypeEndpoint,
0x07, // EndpointAddress
TransferTypeBulk, // Attributes
0x40, // MaxPacketSizeL (64 bytes)
0x00, // MaxPacketSizeH
0x00, // Interval
}
var (
endpointEPIn = [maxEndpoints][endpointTypeLen]byte{}
endpointEPOut = [maxEndpoints][endpointTypeLen]byte{}
)

var EndpointMSCOUT = EndpointType{
data: endpointMSCOUT[:],
func EndpointIN(ep EndpointNumber, transferType uint8, maxPacketSize uint16, interval uint8) EndpointType {
e := EndpointType{data: endpointEPIn[ep][:]}
e.Length(endpointTypeLen)
e.Type(TypeEndpoint)
e.EndpointAddress(uint8(ep+1) | 0x80) // EndpointNumber is 0-based, addresses are 1-based
e.Attributes(transferType)
e.MaxPacketSize(maxPacketSize)
e.Interval(interval)
return e
}

func EndpointOUT(ep EndpointNumber, transferType uint8, maxPacketSize uint16, interval uint8) EndpointType {
e := EndpointType{data: endpointEPOut[ep][:]}
e.Length(endpointTypeLen)
e.Type(TypeEndpoint)
e.EndpointAddress(uint8(ep + 1)) // EndpointNumber is 0-based, addresses are 1-based
e.Attributes(transferType)
e.MaxPacketSize(maxPacketSize)
e.Interval(interval)
return e
}

const (
Expand Down
15 changes: 10 additions & 5 deletions src/machine/usb/descriptor/hid.go
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Original file line number Diff line number Diff line change
Expand Up @@ -111,6 +111,11 @@ var ClassHID = ClassHIDType{
data: classHID[:],
}

// EP1 IN : CDC Call Management
// EP1 OUT: HID OUT
// EP2 IN : HID IN
// EP2 OUT: CDC OUT
// EP3 IN : CDC IN
var CDCHID = Descriptor{
Device: DeviceCDC.Bytes(),
Configuration: Append([][]byte{
Expand All @@ -121,14 +126,14 @@ var CDCHID = Descriptor{
ClassSpecificCDCACM.Bytes(),
ClassSpecificCDCUnion.Bytes(),
ClassSpecificCDCCallManagement.Bytes(),
EndpointEP1IN.Bytes(),
EndpointIN(EndpointEP1, TransferTypeInterrupt, 0x10, 0x10).Bytes(),
InterfaceCDCData.Bytes(),
EndpointEP2OUT.Bytes(),
EndpointEP3IN.Bytes(),
EndpointOUT(EndpointEP2, TransferTypeBulk, 0x40, 0x00).Bytes(),
EndpointIN(EndpointEP3, TransferTypeBulk, 0x40, 0x00).Bytes(),
InterfaceHID.Bytes(),
ClassHID.Bytes(),
EndpointEP4IN.Bytes(),
EndpointEP5OUT.Bytes(),
EndpointIN(EndpointEP2, TransferTypeInterrupt, 0x40, 0x01).Bytes(),
EndpointOUT(EndpointEP1, TransferTypeInterrupt, 0x40, 0x01).Bytes(),
}),
HID: map[uint16][]byte{
2: Append([][]byte{ // Update ClassLength in classHID whenever the array length is modified!
Expand Down
15 changes: 10 additions & 5 deletions src/machine/usb/descriptor/joystick.go
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Original file line number Diff line number Diff line change
Expand Up @@ -121,6 +121,11 @@ var JoystickDefaultHIDReport = Append([][]byte{
// CDCJoystick requires that you append the JoystickDescriptor
// to the Configuration before using. This is in order to support
// custom configurations.
// EP1 IN : CDC Call Management
// EP1 OUT: HID OUT
// EP2 IN : HID IN
// EP2 OUT: CDC OUT
// EP2 IN : CDC IN
var CDCJoystick = Descriptor{
Device: DeviceJoystick.Bytes(),
Configuration: Append([][]byte{
Expand All @@ -131,14 +136,14 @@ var CDCJoystick = Descriptor{
ClassSpecificCDCACM.Bytes(),
ClassSpecificCDCUnion.Bytes(),
ClassSpecificCDCCallManagement.Bytes(),
EndpointEP1IN.Bytes(),
EndpointIN(EndpointEP1, TransferTypeInterrupt, 0x10, 0x10).Bytes(),
InterfaceCDCData.Bytes(),
EndpointEP2OUT.Bytes(),
EndpointEP3IN.Bytes(),
EndpointOUT(EndpointEP2, TransferTypeBulk, 0x40, 0x00).Bytes(),
EndpointIN(EndpointEP3, TransferTypeBulk, 0x40, 0x00).Bytes(),
InterfaceHIDJoystick.Bytes(),
ClassHIDJoystick.Bytes(),
EndpointEP4IN.Bytes(),
EndpointEP5OUT.Bytes(),
EndpointIN(EndpointEP2, TransferTypeInterrupt, 0x40, 0x01).Bytes(),
EndpointOUT(EndpointEP1, TransferTypeInterrupt, 0x40, 0x01).Bytes(),
}),
HID: map[uint16][]byte{},
}
11 changes: 8 additions & 3 deletions src/machine/usb/descriptor/midi.go
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Original file line number Diff line number Diff line change
Expand Up @@ -218,6 +218,11 @@ var ConfigurationCDCMIDI = ConfigurationType{
data: configurationCDCMIDI[:],
}

// EP1 IN : CDC Call Management
// EP2 OUT: CDC OUT
// EP3 IN : CDC IN
// EP6 IN : MIDI IN (custom endpoint descriptor)
// EP7 OUT: MIDI OUT (custom endpoint descriptor)
var CDCMIDI = Descriptor{
Device: DeviceCDC.Bytes(),
Configuration: Append([][]byte{
Expand All @@ -228,10 +233,10 @@ var CDCMIDI = Descriptor{
ClassSpecificCDCACM.Bytes(),
ClassSpecificCDCUnion.Bytes(),
ClassSpecificCDCCallManagement.Bytes(),
EndpointEP1IN.Bytes(),
EndpointIN(EndpointEP1, TransferTypeInterrupt, 0x10, 0x10).Bytes(),
InterfaceCDCData.Bytes(),
EndpointEP2OUT.Bytes(),
EndpointEP3IN.Bytes(),
EndpointOUT(EndpointEP2, TransferTypeBulk, 0x40, 0x00).Bytes(),
EndpointIN(EndpointEP3, TransferTypeBulk, 0x40, 0x00).Bytes(),
InterfaceAssociationMIDI.Bytes(),
InterfaceAudio.Bytes(),
ClassSpecificAudioInterface.Bytes(),
Expand Down
17 changes: 14 additions & 3 deletions src/machine/usb/descriptor/msc.go
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Original file line number Diff line number Diff line change
Expand Up @@ -52,7 +52,18 @@ var ConfigurationMSC = ConfigurationType{
data: configurationMSC[:],
}

var (
EndpointMSCIN = EndpointIN(EndpointEP2, TransferTypeBulk, 0x40, 0x00)
EndpointMSCOUT = EndpointOUT(EndpointEP3, TransferTypeBulk, 0x40, 0x00)
)

// Mass Storage Class
// EP1 IN : CDC Call Management
// EP1 OUT: x
// EP2 IN : MSC IN
// EP2 OUT: CDC OUT
// EP3 IN : CDC IN
// EP3 OUT: MSC OUT
var MSC = Descriptor{
Device: DeviceCDC.Bytes(),
Configuration: Append([][]byte{
Expand All @@ -63,10 +74,10 @@ var MSC = Descriptor{
ClassSpecificCDCACM.Bytes(),
ClassSpecificCDCUnion.Bytes(),
ClassSpecificCDCCallManagement.Bytes(),
EndpointEP1IN.Bytes(),
EndpointIN(EndpointEP1, TransferTypeInterrupt, 0x10, 0x10).Bytes(),
InterfaceCDCData.Bytes(),
EndpointEP2OUT.Bytes(),
EndpointEP3IN.Bytes(),
EndpointOUT(EndpointEP2, TransferTypeBulk, 0x40, 0x00).Bytes(),
EndpointIN(EndpointEP3, TransferTypeBulk, 0x40, 0x00).Bytes(),
InterfaceAssociationMSC.Bytes(),
InterfaceMSC.Bytes(),
EndpointMSCIN.Bytes(),
Expand Down
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