add Interface Association Descriptor

src/machine/usb/desc-cdc.go

@@ -159,6 +159,7 @@ const (
 	descCDCConfigSize = uint16(
 		descLengthConfigure + // Configuration Header
 			descLengthInterface + // CDC Interface Descriptor
+			descLengthInterfaceAssociation + // IAD
 			descCDCFuncLengthHeader + // CDC Header
 			descCDCFuncLengthCallManagement + // CDC Call Management Func Descriptor
 			descCDCFuncLengthAbstractControl + // CDC Abstract Control Func Descriptor
@@ -282,9 +283,9 @@ var descCDC = [dcdCount]descCDCClass{
 			descTypeDevice,            // Descriptor Type
 			lsU8(descUSBSpecVersion),  // USB Specification Release Number in BCD (low)
 			msU8(descUSBSpecVersion),  // USB Specification Release Number in BCD (high)
-			0,                         // Class code (assigned by the USB-IF).
-			0,                         // Subclass code (assigned by the USB-IF).
-			0,                         // Protocol code (assigned by the USB-IF).
+			descDeviceClassCodeMisc,   // Class code (assigned by the USB-IF).
+			descDeviceSubClassCommon,  // Subclass code (assigned by the USB-IF).
+			descDeviceProtocolIAD,     // Protocol code (assigned by the USB-IF).
 			descEndptMaxPktSize,       // Maximum packet size for endpoint zero (8, 16, 32, or 64)
 			lsU8(descCommonVendorID),  // Vendor ID (low) (assigned by the USB-IF)
 			msU8(descCommonVendorID),  // Vendor ID (high) (assigned by the USB-IF)
@@ -320,6 +321,16 @@ var descCDC = [dcdCount]descCDCClass{
 			descEndptConfigAttr,     // Configuration attributes
 			descCDCMaxPowerMa >> 1,  // Max power consumption when fully-operational (2 mA units)
 
+			// Interface Association Descriptor
+			descLengthInterfaceAssociation, // Size of this descriptor in bytes
+			descTypeInterfaceAssociation,   // Descriptor Type
+			0x00,                           // bFirstInterface
+			descCDCInterfaceCount,          // bInterfaceCount
+			0x02,                           // bFunctionClass  : Communications and CDC Control (0x02)
+			0x02,                           // bFunctionSubClass
+			0x00,                           // bFunctionProtocol
+			0x00,                           // iFunction
+
 			// Communication/Control Interface Descriptor
 			descLengthInterface,       // Descriptor length
 			descTypeInterface,         // Descriptor type

src/machine/usb/desc.go

@@ -8,16 +8,17 @@ const descLanguageEnglish = uint16(0x0409) // (US) English
 const (
 
 	// Descriptor length
-	descLengthDevice            = 18
-	descLengthConfigure         = 9
-	descLengthInterface         = 9
-	descLengthEndpoint          = 7
-	descLengthQualification     = 10
-	descLengthOTG               = 5
-	descLengthBOS               = 5
-	descLengthEndpointCompanion = 6
-	descLengthUSB20Extension    = 7
-	descLengthSuperspeed        = 10
+	descLengthDevice               = 18
+	descLengthConfigure            = 9
+	descLengthInterface            = 9
+	descLengthInterfaceAssociation = 8
+	descLengthEndpoint             = 7
+	descLengthQualification        = 10
+	descLengthOTG                  = 5
+	descLengthBOS                  = 5
+	descLengthEndpointCompanion    = 6
+	descLengthUSB20Extension       = 7
+	descLengthSuperspeed           = 10
 
 	// Descriptor type
 	descTypeDevice                  = 0x01
@@ -133,6 +134,11 @@ const (
 	descDeviceCapExtAttrLPMPos  = 1
 	descDeviceCapExtAttrBESLMsk = 0x04
 	descDeviceCapExtAttrBESLPos = 2
+
+	// Device class
+	descDeviceClassCodeMisc  = 0xEF
+	descDeviceSubClassCommon = 0x02
+	descDeviceProtocolIAD    = 0x01
 )
 
 // descEndpointInvalid represents an invalid endpoint address.