machine: implement usb receive message throttling

mikesmitty · mikesmitty · commit 1c53ff1d601d · 2025-06-09T11:17:10.000-04:00
diff --git a/src/machine/machine_atsamd21_usb.go b/src/machine/machine_atsamd21_usb.go
@@ -194,10 +194,9 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 		setEPINTFLAG(i, epFlags)
 		if (epFlags & sam.USB_DEVICE_EPINTFLAG_TRCPT0) > 0 {
 			buf := handleEndpointRx(i)
-			if usbRxHandler[i] != nil {
-				usbRxHandler[i](buf)
+			if usbRxHandler[i] == nil || usbRxHandler[i](buf) {
+				AckUsbOutTransfer(i)
 			}
-			handleEndpointRxComplete(i)
 		} else if (epFlags & sam.USB_DEVICE_EPINTFLAG_TRCPT1) > 0 {
 			if usbTxHandler[i] != nil {
 				usbTxHandler[i]()
@@ -417,7 +416,8 @@ func handleEndpointRx(ep uint32) []byte {
 	return udd_ep_out_cache_buffer[ep][:count]
 }
 
-func handleEndpointRxComplete(ep uint32) {
+// AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.
+func AckUsbOutTransfer(ep uint32) {
 	// set byte count to zero
 	usbEndpointDescriptors[ep].DeviceDescBank[0].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
 
diff --git a/src/machine/machine_atsamd51_usb.go b/src/machine/machine_atsamd51_usb.go
@@ -197,10 +197,9 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 		setEPINTFLAG(i, epFlags)
 		if (epFlags & sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT0) > 0 {
 			buf := handleEndpointRx(i)
-			if usbRxHandler[i] != nil {
-				usbRxHandler[i](buf)
+			if usbRxHandler[i] == nil || usbRxHandler[i](buf) {
+				AckUsbOutTransfer(i)
 			}
-			handleEndpointRxComplete(i)
 		} else if (epFlags & sam.USB_DEVICE_ENDPOINT_EPINTFLAG_TRCPT1) > 0 {
 			if usbTxHandler[i] != nil {
 				usbTxHandler[i]()
@@ -420,7 +419,8 @@ func handleEndpointRx(ep uint32) []byte {
 	return udd_ep_out_cache_buffer[ep][:count]
 }
 
-func handleEndpointRxComplete(ep uint32) {
+// AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.
+func AckUsbOutTransfer(ep uint32) {
 	// set byte count to zero
 	usbEndpointDescriptors[ep].DeviceDescBank[0].PCKSIZE.ClearBits(usb_DEVICE_PCKSIZE_BYTE_COUNT_Mask << usb_DEVICE_PCKSIZE_BYTE_COUNT_Pos)
 
diff --git a/src/machine/machine_nrf52840_usb.go b/src/machine/machine_nrf52840_usb.go
@@ -206,10 +206,9 @@ func handleUSBIRQ(interrupt.Interrupt) {
 		if nrf.USBD.EVENTS_ENDEPOUT[i].Get() > 0 {
 			nrf.USBD.EVENTS_ENDEPOUT[i].Set(0)
 			buf := handleEndpointRx(uint32(i))
-			if usbRxHandler[i] != nil {
-				usbRxHandler[i](buf)
+			if usbRxHandler[i] == nil || usbRxHandler[i](buf) {
+				AckUsbOutTransfer(uint32(i))
 			}
-			handleEndpointRxComplete(uint32(i))
 			exitCriticalSection()
 		}
 	}
@@ -304,7 +303,8 @@ func handleEndpointRx(ep uint32) []byte {
 	return udd_ep_out_cache_buffer[ep][:count]
 }
 
-func handleEndpointRxComplete(ep uint32) {
+// AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.
+func AckUsbOutTransfer(ep uint32) {
 	// set ready for next data
 	nrf.USBD.SIZE.EPOUT[ep].Set(0)
 }
diff --git a/src/machine/machine_rp2040_usb.go b/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) {
+					AckUsbOutTransfer(uint32(i))
 				}
-				handleEndpointRxComplete(uint32(i))
 			}
 		}
 
diff --git a/src/machine/machine_rp2350_usb.go b/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) {
+					AckUsbOutTransfer(uint32(i))
 				}
-				handleEndpointRxComplete(uint32(i))
 			}
 		}
 
diff --git a/src/machine/machine_rp2_usb.go b/src/machine/machine_rp2_usb.go
@@ -128,7 +128,8 @@ func handleEndpointRx(ep uint32) []byte {
 	return _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz]
 }
 
-func handleEndpointRxComplete(ep uint32) {
+// AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.
+func AckUsbOutTransfer(ep uint32) {
 	ep = ep & 0x7F
 	setEPDataPID(ep, !epXdata0[ep])
 }
diff --git a/src/machine/usb.go b/src/machine/usb.go
@@ -319,7 +319,12 @@ 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 {
diff --git a/src/machine/usb/config.go b/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 {

Original file line number	Diff line number	Diff line change
`@@ -206,10 +206,9 @@ func handleUSBIRQ(interrupt.Interrupt) {`
`206`	`206`	`if nrf.USBD.EVENTS_ENDEPOUT[i].Get() > 0 {`
`207`	`207`	`nrf.USBD.EVENTS_ENDEPOUT[i].Set(0)`
`208`	`208`	`buf := handleEndpointRx(uint32(i))`
`209`		`- if usbRxHandler[i] != nil {`
`210`		`- usbRxHandler[i](buf)`
	`209`	`+ if usbRxHandler[i] == nil \|\| usbRxHandler[i](buf) {`
	`210`	`+ AckUsbOutTransfer(uint32(i))`
`211`	`211`	`}`
`212`		`- handleEndpointRxComplete(uint32(i))`
`213`	`212`	`exitCriticalSection()`
`214`	`213`	`}`
`215`	`214`	`}`
`@@ -304,7 +303,8 @@ func handleEndpointRx(ep uint32) []byte {`
`304`	`303`	`return udd_ep_out_cache_buffer[ep][:count]`
`305`	`304`	`}`
`306`	`305`
`307`		`-func handleEndpointRxComplete(ep uint32) {`
	`306`	`+// AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.`
	`307`	`+func AckUsbOutTransfer(ep uint32) {`
`308`	`308`	`// set ready for next data`
`309`	`309`	`nrf.USBD.SIZE.EPOUT[ep].Set(0)`
`310`	`310`	`}`
Original file line number	Diff line number	Diff line change
`@@ -95,10 +95,9 @@ func handleUSBIRQ(intr interrupt.Interrupt) {`
`95`	`95`	`for i := 0; i < 16; i++ {`
`96`	`96`	`if s2&(1<<(i*2+1)) > 0 {`
`97`	`97`	`buf := handleEndpointRx(uint32(i))`
`98`		`- if usbRxHandler[i] != nil {`
`99`		`- usbRxHandler[i](buf)`
	`98`	`+ if usbRxHandler[i] == nil \|\| usbRxHandler[i](buf) {`
	`99`	`+ AckUsbOutTransfer(uint32(i))`
`100`	`100`	`}`
`101`		`- handleEndpointRxComplete(uint32(i))`
`102`	`101`	`}`
`103`	`102`	`}`
`104`	`103`
Original file line number	Diff line number	Diff line change
`@@ -98,10 +98,9 @@ func handleUSBIRQ(intr interrupt.Interrupt) {`
`98`	`98`	`for i := 0; i < 16; i++ {`
`99`	`99`	`if s2&(1<<(i*2+1)) > 0 {`
`100`	`100`	`buf := handleEndpointRx(uint32(i))`
`101`		`- if usbRxHandler[i] != nil {`
`102`		`- usbRxHandler[i](buf)`
	`101`	`+ if usbRxHandler[i] == nil \|\| usbRxHandler[i](buf) {`
	`102`	`+ AckUsbOutTransfer(uint32(i))`
`103`	`103`	`}`
`104`		`- handleEndpointRxComplete(uint32(i))`
`105`	`104`	`}`
`106`	`105`	`}`
`107`	`106`
Original file line number	Diff line number	Diff line change
`@@ -128,7 +128,8 @@ func handleEndpointRx(ep uint32) []byte {`
`128`	`128`	`return _usbDPSRAM.EPxBuffer[ep].Buffer0[:sz]`
`129`	`129`	`}`
`130`	`130`
`131`		`-func handleEndpointRxComplete(ep uint32) {`
	`131`	`+// AckUsbOutTransfer is called to acknowledge the completion of a USB OUT transfer.`
	`132`	`+func AckUsbOutTransfer(ep uint32) {`
`132`	`133`	`ep = ep & 0x7F`
`133`	`134`	`setEPDataPID(ep, !epXdata0[ep])`
`134`	`135`	`}`
Original file line number	Diff line number	Diff line change
`@@ -319,7 +319,12 @@ func ConfigureUSBEndpoint(desc descriptor.Descriptor, epSettings []usb.EndpointC`
`319`	`319`	`} else {`
`320`	`320`	`endPoints[ep.Index] = uint32(ep.Type \| usb.EndpointOut)`
`321`	`321`	`if ep.RxHandler != nil {`
`322`		`- usbRxHandler[ep.Index] = ep.RxHandler`
	`322`	`+ usbRxHandler[ep.Index] = func(b []byte) bool {`
	`323`	`+ ep.RxHandler(b)`
	`324`	`+ return true`
	`325`	`+ }`
	`326`	`+ } else if ep.DelayRxHandler != nil {`
	`327`	`+ usbRxHandler[ep.Index] = ep.DelayRxHandler`
`323`	`328`	`}`
`324`	`329`	`}`
`325`	`330`	`if ep.StallHandler != nil {`