rp2040: fix usb device enumeration (RP2040-E5)

src/machine/machine_rp2040_usb.go

@@ -130,6 +130,7 @@ func handleUSBIRQ(intr interrupt.Interrupt) {
 		rp.USBCTRL_REGS.ADDR_ENDP.Set(0)
 
 		initEndpoint(0, usb.ENDPOINT_TYPE_CONTROL)
+		fixRP2040UsbDeviceEnumeration()
 	}
 }
 

src/machine/machine_rp2040_usb_fix_usb_device_enumeration.go

@@ -0,0 +1,101 @@
+//go:build rp2040
+// +build rp2040
+
+package machine
+
+import (
+	"device/rp"
+)
+
+// https://github.com/raspberrypi/pico-sdk/blob/master/src/rp2_common/pico_fix/rp2040_usb_device_enumeration/rp2040_usb_device_enumeration.c
+func fixRP2040UsbDeviceEnumeration() {
+
+	// Wait SE0 phase will call force ls_j phase which will call finish phase
+	hw_enumeration_fix_wait_se0()
+}
+
+func hw_enumeration_fix_wait_se0() {
+	// Wait for SE0 to end (i.e. the host to stop resetting). This reset can last quite long.
+	// 10-15ms so we are going to set a timer callback.
+
+	// if timer pool disabled, or no timer available, have to busy wait.
+	hw_enumeration_fix_busy_wait_se0()
+}
+
+const (
+	LS_SE0 = 0b00
+	LS_J   = 0b01
+	LS_K   = 0b10
+	LS_SE1 = 0b11
+)
+
+const (
+	dp = 15
+)
+
+var (
+	gpioCtrlPrev uint32
+	padCtrlPrev  uint32
+)
+
+func hw_enumeration_fix_busy_wait_se0() {
+	for ((rp.USBCTRL_REGS.SIE_STATUS.Get() & rp.USBCTRL_REGS_SIE_STATUS_LINE_STATE_Msk) >> rp.USBCTRL_REGS_SIE_STATUS_LINE_STATE_Pos) == LS_SE0 {
+	}
+
+	// Now force LS_J (next stage of fix)
+	hw_enumeration_fix_force_ls_j()
+}
+
+func hw_enumeration_fix_force_ls_j() {
+	// DM must be 0 for this to work. This is true if it is selected
+	// to any other function. fn 8 on this pin is only for debug so shouldn't
+	// be selected
+
+	// Before changing any pin state, take a copy of the current gpio control register
+	gpioCtrlPrev = ioBank0.io[dp].ctrl.Get()
+	// Also take a copy of the pads register
+	padCtrlPrev = padsBank0.io[dp].Get()
+
+	// Enable bus keep and force pin to tristate, so USB DP muxing doesn't affect
+	// pin state
+	padsBank0.io[dp].SetBits(rp.PADS_BANK0_GPIO0_PUE | rp.PADS_BANK0_GPIO0_PDE)
+	ioBank0.io[dp].ctrl.ReplaceBits(rp.IO_BANK0_GPIO0_CTRL_OEOVER_DISABLE, rp.IO_BANK0_GPIO0_CTRL_OEOVER_Msk>>rp.IO_BANK0_GPIO0_CTRL_OEOVER_Pos, rp.IO_BANK0_GPIO0_CTRL_OEOVER_Pos)
+
+	// Select function 8 (USB debug muxing) without disturbing other controls
+	ioBank0.io[dp].ctrl.ReplaceBits(8, rp.IO_BANK0_GPIO0_CTRL_FUNCSEL_Msk>>rp.IO_BANK0_GPIO0_CTRL_FUNCSEL_Pos, rp.IO_BANK0_GPIO0_CTRL_FUNCSEL_Pos)
+
+	// J state is a differential 1 for a full speed device so
+	// DP = 1 and DM = 0. Don't actually need to set DM low as it
+	// is already gated assuming it isn't funcseld.
+	ioBank0.io[dp].ctrl.ReplaceBits(rp.IO_BANK0_GPIO1_CTRL_INOVER_HIGH, rp.IO_BANK0_GPIO1_CTRL_INOVER_Msk>>rp.IO_BANK0_GPIO1_CTRL_INOVER_Pos, rp.IO_BANK0_GPIO1_CTRL_INOVER_Pos)
+
+	// Force PHY pull up to stay before switching away from the phy
+	rp.USBCTRL_REGS.USBPHY_DIRECT.SetBits(rp.USBCTRL_REGS_USBPHY_DIRECT_DP_PULLUP_EN)
+	rp.USBCTRL_REGS.USBPHY_DIRECT_OVERRIDE.SetBits(rp.USBCTRL_REGS_USBPHY_DIRECT_OVERRIDE_DP_PULLUP_EN_OVERRIDE_EN)
+
+	// Switch to GPIO phy with LS_J forced
+	rp.USBCTRL_REGS.USB_MUXING.Set(rp.USBCTRL_REGS_USB_MUXING_TO_DIGITAL_PAD | rp.USBCTRL_REGS_USB_MUXING_SOFTCON)
+
+	// LS_J is now forced but while loop here just to check
+
+	// if timer pool disabled, or no timer available, have to busy wait.
+	hw_enumeration_fix_finish()
+
+}
+
+func hw_enumeration_fix_finish() {
+	// Should think we are connected now
+	for (rp.USBCTRL_REGS.SIE_STATUS.Get() & rp.USBCTRL_REGS_SIE_STATUS_CONNECTED) != rp.USBCTRL_REGS_SIE_STATUS_CONNECTED {
+	}
+
+	// Switch back to USB phy
+	rp.USBCTRL_REGS.USB_MUXING.Set(rp.USBCTRL_REGS_USB_MUXING_TO_PHY | rp.USBCTRL_REGS_USB_MUXING_SOFTCON)
+
+	// Get rid of DP pullup override
+	rp.USBCTRL_REGS.USBPHY_DIRECT_OVERRIDE.ClearBits(rp.USBCTRL_REGS_USBPHY_DIRECT_OVERRIDE_DP_PULLUP_EN_OVERRIDE_EN)
+
+	// Finally, restore the gpio ctrl value back to GPIO15
+	ioBank0.io[dp].ctrl.Set(gpioCtrlPrev)
+	// Restore the pad ctrl value
+	padsBank0.io[dp].Set(padCtrlPrev)
+}