fix(rp2040): replace loop counter with hw timer for USB SetAddressReq… (#4796)

* fix(rp2040/rp2350): replace loop counter with hw timer for USB SetAddressRequest timeout.

* fix code format.

---------

Co-authored-by: rdon <you@example.com>

src/machine/machine_rp2040_usb.go

@@ -169,21 +169,22 @@ func initEndpoint(ep, config uint32) {
 }
 
 func handleUSBSetAddress(setup usb.Setup) bool {
+	// Using 570μs timeout which is exactly the same as SAMD21.
+	const ackTimeout = 570
+
+	rp.USBCTRL_REGS.SIE_STATUS.Set(rp.USBCTRL_REGS_SIE_STATUS_ACK_REC)
 	sendUSBPacket(0, []byte{}, 0)
 
-	// last, set the device address to that requested by host
+	// Wait for transfer to complete with a timeout.
-	// wait for transfer to complete
+	t := timer.timeElapsed()
-	timeout := 3000
-	rp.USBCTRL_REGS.SIE_STATUS.Set(rp.USBCTRL_REGS_SIE_STATUS_ACK_REC)
 	for (rp.USBCTRL_REGS.SIE_STATUS.Get() & rp.USBCTRL_REGS_SIE_STATUS_ACK_REC) == 0 {
-		timeout--
+		if dt := timer.timeElapsed() - t; dt >= ackTimeout {
-		if timeout == 0 {
+			return false
-			return true
 		}
 	}
 
+	// Set the device address to that requested by host.
 	rp.USBCTRL_REGS.ADDR_ENDP.Set(uint32(setup.WValueL) & rp.USBCTRL_REGS_ADDR_ENDP_ADDRESS_Msk)
-
 	return true
 }
 

src/machine/machine_rp2350_usb.go

@@ -172,21 +172,22 @@ func initEndpoint(ep, config uint32) {
 }
 
 func handleUSBSetAddress(setup usb.Setup) bool {
+	// Using 570μs timeout which is exactly the same as SAMD21.
+
+	const ackTimeout = 570
+	rp.USB.SIE_STATUS.Set(rp.USB_SIE_STATUS_ACK_REC)
 	sendUSBPacket(0, []byte{}, 0)
 
-	// last, set the device address to that requested by host
+	// Wait for transfer to complete with a timeout.
-	// wait for transfer to complete
+	t := timer.timeElapsed()
-	timeout := 3000
-	rp.USB.SIE_STATUS.Set(rp.USB_SIE_STATUS_ACK_REC)
 	for (rp.USB.SIE_STATUS.Get() & rp.USB_SIE_STATUS_ACK_REC) == 0 {
-		timeout--
+		if dt := timer.timeElapsed() - t; dt >= ackTimeout {
-		if timeout == 0 {
+			return false
-			return true
 		}
 	}
 
+	// Set the device address to that requested by host.
 	rp.USB.ADDR_ENDP.Set(uint32(setup.WValueL) & rp.USB_ADDR_ENDP_ADDRESS_Msk)
-
 	return true
 }