rp2040: add support for usb (#2973)

* rp2040: add support for usb

4 files changed, 364 insertions, 5 deletions

diff --git a/src/machine/machine_rp2040_usb.go b/src/machine/machine_rp2040_usb.go
new file mode 100644
index 000000000..865b2bece
--- /dev/null
+++ b/src/machine/machine_rp2040_usb.go
@@ -0,0 +1,357 @@
+//go:build rp2040
+// +build rp2040
+
+package machine
+
+import (
+	"device/arm"
+	"device/rp"
+	"runtime/interrupt"
+	"unsafe"
+)
+
+var (
+	sendOnEP0DATADONE struct {
+		offset int
+		data   []byte
+		pid    uint32
+	}
+)
+
+// Configure the USB peripheral. The config is here for compatibility with the UART interface.
+func (dev *USBDevice) Configure(config UARTConfig) {
+	//// Clear any previous state in dpram just in case
+	usbDPSRAM.clear()
+
+	//// Enable USB interrupt at processor
+	rp.USBCTRL_REGS.INTE.Set(0)
+	intr := interrupt.New(rp.IRQ_USBCTRL_IRQ, handleUSBIRQ)
+	intr.SetPriority(0x00)
+	intr.Enable()
+	irqSet(rp.IRQ_USBCTRL_IRQ, true)
+
+	//// Mux the controller to the onboard usb phy
+	rp.USBCTRL_REGS.USB_MUXING.Set(rp.USBCTRL_REGS_USB_MUXING_TO_PHY | rp.USBCTRL_REGS_USB_MUXING_SOFTCON)
+
+	//// Force VBUS detect so the device thinks it is plugged into a host
+	rp.USBCTRL_REGS.USB_PWR.Set(rp.USBCTRL_REGS_USB_PWR_VBUS_DETECT | rp.USBCTRL_REGS_USB_PWR_VBUS_DETECT_OVERRIDE_EN)
+
+	//// Enable the USB controller in device mode.
+	rp.USBCTRL_REGS.MAIN_CTRL.Set(rp.USBCTRL_REGS_MAIN_CTRL_CONTROLLER_EN)
+
+	//// Enable an interrupt per EP0 transaction
+	rp.USBCTRL_REGS.SIE_CTRL.Set(rp.USBCTRL_REGS_SIE_CTRL_EP0_INT_1BUF)
+
+	//// Enable interrupts for when a buffer is done, when the bus is reset,
+	//// and when a setup packet is received
+	rp.USBCTRL_REGS.INTE.Set(rp.USBCTRL_REGS_INTE_BUFF_STATUS |
+		rp.USBCTRL_REGS_INTE_BUS_RESET |
+		rp.USBCTRL_REGS_INTE_SETUP_REQ)
+
+	//// Present full speed device by enabling pull up on DP
+	rp.USBCTRL_REGS.SIE_CTRL.SetBits(rp.USBCTRL_REGS_SIE_CTRL_PULLUP_EN)
+}
+
+func handleUSBIRQ(intr interrupt.Interrupt) {
+	status := rp.USBCTRL_REGS.INTS.Get()
+
+	// Setup packet received
+	if (status & rp.USBCTRL_REGS_INTS_SETUP_REQ) > 0 {
+		rp.USBCTRL_REGS.SIE_STATUS.Set(rp.USBCTRL_REGS_SIE_STATUS_SETUP_REC)
+		setup := newUSBSetup(usbDPSRAM.setupBytes())
+
+		ok := false
+		if (setup.BmRequestType & usb_REQUEST_TYPE) == usb_REQUEST_STANDARD {
+			// Standard Requests
+			ok = handleStandardSetup(setup)
+		} else {
+			// Class Interface Requests
+			if setup.WIndex < uint16(len(usbSetupHandler)) && usbSetupHandler[setup.WIndex] != nil {
+				ok = usbSetupHandler[setup.WIndex](setup)
+			}
+		}
+
+		if !ok {
+			// Stall endpoint?
+			sendStallViaEPIn(0)
+		}
+
+	}
+
+	// Buffer status, one or more buffers have completed
+	if (status & rp.USBCTRL_REGS_INTS_BUFF_STATUS) > 0 {
+		if sendOnEP0DATADONE.offset > 0 {
+			ep := uint32(0)
+			data := sendOnEP0DATADONE.data
+			count := len(data) - sendOnEP0DATADONE.offset
+			if ep == 0 && count > usbEndpointPacketSize {
+				count = usbEndpointPacketSize
+			}
+
+			sendViaEPIn(ep, data[sendOnEP0DATADONE.offset:], count)
+			sendOnEP0DATADONE.offset += count
+			if sendOnEP0DATADONE.offset == len(data) {
+				sendOnEP0DATADONE.offset = 0
+			}
+		}
+
+		s2 := rp.USBCTRL_REGS.BUFF_STATUS.Get()
+
+		// OUT (PC -> rp2040)
+		for i := 0; i < 16; i++ {
+			if s2&(1<<(i*2+1)) > 0 {
+				buf := handleEndpointRx(uint32(i))
+				if usbRxHandler[i] != nil {
+					usbRxHandler[i](buf)
+				}
+			}
+		}
+
+		// IN (rp2040 -> PC)
+		for i := 0; i < 16; i++ {
+			if s2&(1<<(i*2)) > 0 {
+				if usbTxHandler[i] != nil {
+					usbTxHandler[i]()
+				}
+			}
+		}
+
+		rp.USBCTRL_REGS.BUFF_STATUS.Set(0xFFFFFFFF)
+	}
+
+	// Bus is reset
+	if (status & rp.USBCTRL_REGS_INTS_BUS_RESET) > 0 {
+		rp.USBCTRL_REGS.SIE_STATUS.Set(rp.USBCTRL_REGS_SIE_STATUS_BUS_RESET)
+		initEndpoint(0, usb_ENDPOINT_TYPE_CONTROL)
+	}
+}
+
+func initEndpoint(ep, config uint32) {
+	val := uint32(usbEpControlEnable) | uint32(usbEpControlInterruptPerBuff)
+	offset := ep*2*USBBufferLen + 0x100
+	val |= offset
+
+	switch config {
+	case usb_ENDPOINT_TYPE_INTERRUPT | usbEndpointIn:
+		val |= usbEpControlEndpointTypeInterrupt
+		usbDPSRAM.EPxControl[ep].In = val
+
+	case usb_ENDPOINT_TYPE_BULK | usbEndpointOut:
+		val |= usbEpControlEndpointTypeBulk
+		usbDPSRAM.EPxControl[ep].Out = val
+		usbDPSRAM.EPxBufferControl[ep].Out = USBBufferLen & usbBuf0CtrlLenMask
+		usbDPSRAM.EPxBufferControl[ep].Out |= usbBuf0CtrlAvail
+
+	case usb_ENDPOINT_TYPE_INTERRUPT | usbEndpointOut:
+		// TODO: not really anything, seems like...
+
+	case usb_ENDPOINT_TYPE_BULK | usbEndpointIn:
+		val |= usbEpControlEndpointTypeBulk
+		usbDPSRAM.EPxControl[ep].In = val
+
+	case usb_ENDPOINT_TYPE_CONTROL:
+		val |= usbEpControlEndpointTypeControl
+		usbDPSRAM.EPxBufferControl[ep].Out = usbBuf0CtrlAvail
+
+	}
+}
+
+func handleUSBSetAddress(setup USBSetup) bool {
+	sendUSBPacket(0, []byte{}, 0)
+
+	// last, set the device address to that requested by host
+	// wait for transfer to complete
+	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 timeout == 0 {
+			return true
+		}
+	}
+
+	rp.USBCTRL_REGS.ADDR_ENDP.Set(uint32(setup.WValueL) & rp.USBCTRL_REGS_ADDR_ENDP_ADDRESS_Msk)
+
+	return true
+}
+
+// SendUSBInPacket sends a packet for USB (interrupt in / bulk in).
+func SendUSBInPacket(ep uint32, data []byte) bool {
+	sendUSBPacket(ep, data, 0)
+	return true
+}
+
+//go:noinline
+func sendUSBPacket(ep uint32, data []byte, maxsize uint16) {
+	count := len(data)
+	if 0 < int(maxsize) && int(maxsize) < count {
+		count = int(maxsize)
+	}
+
+	if ep == 0 {
+		if count > usbEndpointPacketSize {
+			count = usbEndpointPacketSize
+
+			sendOnEP0DATADONE.offset = count
+			sendOnEP0DATADONE.data = data
+		} else {
+			sendOnEP0DATADONE.offset = 0
+		}
+		epXdata0[ep] = true
+	}
+
+	sendViaEPIn(ep, data, count)
+}
+
+func ReceiveUSBControlPacket() ([cdcLineInfoSize]byte, error) {
+	var b [cdcLineInfoSize]byte
+	return b, nil
+}
+
+func handleEndpointRx(ep uint32) []byte {
+	ctrl := usbDPSRAM.EPxBufferControl[ep].Out
+	usbDPSRAM.EPxBufferControl[ep].Out = USBBufferLen & usbBuf0CtrlLenMask
+	sz := ctrl & usbBuf0CtrlLenMask
+	buf := make([]byte, sz)
+	copy(buf, usbDPSRAM.EPxBuffer[ep].Buffer0[:sz])
+
+	epXdata0[ep] = !epXdata0[ep]
+	if epXdata0[ep] {
+		usbDPSRAM.EPxBufferControl[ep].Out |= usbBuf0CtrlData1Pid
+	}
+
+	usbDPSRAM.EPxBufferControl[ep].Out |= usbBuf0CtrlAvail
+
+	return buf
+}
+
+func SendZlp() {
+	sendUSBPacket(0, []byte{}, 0)
+}
+
+func sendViaEPIn(ep uint32, data []byte, count int) {
+	// Prepare buffer control register value
+	val := uint32(count) | usbBuf0CtrlAvail
+
+	// DATA0 or DATA1
+	epXdata0[ep&0x7F] = !epXdata0[ep&0x7F]
+	if !epXdata0[ep&0x7F] {
+		val |= usbBuf0CtrlData1Pid
+	}
+
+	// Mark as full
+	val |= usbBuf0CtrlFull
+
+	copy(usbDPSRAM.EPxBuffer[ep&0x7F].Buffer0[:], data[:count])
+	usbDPSRAM.EPxBufferControl[ep&0x7F].In = val
+}
+
+func sendStallViaEPIn(ep uint32) {
+	// Prepare buffer control register value
+	if ep == 0 {
+		rp.USBCTRL_REGS.EP_STALL_ARM.Set(rp.USBCTRL_REGS_EP_STALL_ARM_EP0_IN)
+	}
+	val := uint32(usbBuf0CtrlFull)
+	usbDPSRAM.EPxBufferControl[ep&0x7F].In = val
+	val |= uint32(usbBuf0CtrlStall)
+	usbDPSRAM.EPxBufferControl[ep&0x7F].In = val
+}
+
+// EnterBootloader should perform a system reset in preparation
+// to switch to the bootloader to flash new firmware.
+func EnterBootloader() {
+	arm.DisableInterrupts()
+
+	// TODO: Perform magic reset into bootloader
+
+	arm.SystemReset()
+}
+
+type USBDPSRAM struct {
+	// Note that EPxControl[0] is not EP0Control but 8-byte setup data.
+	EPxControl [16]USBEndpointControlRegister
+
+	EPxBufferControl [16]USBBufferControlRegister
+
+	EPxBuffer [16]USBBuffer
+}
+
+type USBEndpointControlRegister struct {
+	In  uint32
+	Out uint32
+}
+type USBBufferControlRegister struct {
+	In  uint32
+	Out uint32
+}
+
+type USBBuffer struct {
+	Buffer0 [USBBufferLen]byte
+	Buffer1 [USBBufferLen]byte
+}
+
+var (
+	usbDPSRAM = (*USBDPSRAM)(unsafe.Pointer(uintptr(0x50100000)))
+	epXdata0  [16]bool
+)
+
+func (d *USBDPSRAM) setupBytes() []byte {
+	var buf [8]byte
+
+	buf[0] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].In)
+	buf[1] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].In >> 8)
+	buf[2] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].In >> 16)
+	buf[3] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].In >> 24)
+	buf[4] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].Out)
+	buf[5] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].Out >> 8)
+	buf[6] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].Out >> 16)
+	buf[7] = byte(d.EPxControl[usb_CONTROL_ENDPOINT].Out >> 24)
+
+	return buf[:]
+}
+
+func (d *USBDPSRAM) clear() {
+	for i := 0; i < len(d.EPxControl); i++ {
+		d.EPxControl[i].In = 0
+		d.EPxControl[i].Out = 0
+		d.EPxBufferControl[i].In = 0
+		d.EPxBufferControl[i].Out = 0
+	}
+}
+
+const (
+	// DPRAM : Endpoint control register
+	usbEpControlEnable                 = 0x80000000
+	usbEpControlDoubleBuffered         = 0x40000000
+	usbEpControlInterruptPerBuff       = 0x20000000
+	usbEpControlInterruptPerDoubleBuff = 0x10000000
+	usbEpControlEndpointType           = 0x0c000000
+	usbEpControlInterruptOnStall       = 0x00020000
+	usbEpControlInterruptOnNak         = 0x00010000
+	usbEpControlBufferAddress          = 0x0000ffff
+
+	usbEpControlEndpointTypeControl   = 0x00000000
+	usbEpControlEndpointTypeISO       = 0x04000000
+	usbEpControlEndpointTypeBulk      = 0x08000000
+	usbEpControlEndpointTypeInterrupt = 0x0c000000
+
+	// Endpoint buffer control bits
+	usbBuf1CtrlFull     = 0x80000000
+	usbBuf1CtrlLast     = 0x40000000
+	usbBuf1CtrlData0Pid = 0x20000000
+	usbBuf1CtrlData1Pid = 0x00000000
+	usbBuf1CtrlSel      = 0x10000000
+	usbBuf1CtrlStall    = 0x08000000
+	usbBuf1CtrlAvail    = 0x04000000
+	usbBuf1CtrlLenMask  = 0x03FF0000
+	usbBuf0CtrlFull     = 0x00008000
+	usbBuf0CtrlLast     = 0x00004000
+	usbBuf0CtrlData0Pid = 0x00000000
+	usbBuf0CtrlData1Pid = 0x00002000
+	usbBuf0CtrlSel      = 0x00001000
+	usbBuf0CtrlStall    = 0x00000800
+	usbBuf0CtrlAvail    = 0x00000400
+	usbBuf0CtrlLenMask  = 0x000003FF
+
+	USBBufferLen = 64
+)
diff --git a/src/machine/usb.go b/src/machine/usb.go
index 3656edc7b..39f8177a5 100644
--- a/src/machine/usb.go
+++ b/src/machine/usb.go
@@ -1,5 +1,5 @@
-//go:build sam || nrf52840
-// +build sam nrf52840
+//go:build sam || nrf52840 || rp2040
+// +build sam nrf52840 rp2040
 
 package machine
 
diff --git a/src/machine/usb_descriptor.go b/src/machine/usb_descriptor.go
index 4489a546b..b6acb9b62 100644
--- a/src/machine/usb_descriptor.go
+++ b/src/machine/usb_descriptor.go
@@ -1,5 +1,5 @@
-//go:build sam || nrf52840
-// +build sam nrf52840
+//go:build sam || nrf52840 || rp2040
+// +build sam nrf52840 rp2040
 
 package machine
 
diff --git a/src/runtime/runtime_rp2040.go b/src/runtime/runtime_rp2040.go
index ad1e67fbe..089c91eda 100644
--- a/src/runtime/runtime_rp2040.go
+++ b/src/runtime/runtime_rp2040.go
@@ -5,8 +5,8 @@ package runtime
 
 import (
 	"device/arm"
-
 	"machine"
+	"machine/usb/cdc"
 )
 
 // machineTicks is provided by package machine.
@@ -76,6 +76,8 @@ func machineInit()
 func init() {
 	machineInit()
 
+	cdc.EnableUSBCDC()
+	machine.USBDev.Configure(machine.UARTConfig{})
 	machine.InitSerial()
 }