From f639d800125d343c0b326b2898ee7b04d67de3d0 Mon Sep 17 00:00:00 2001
From: deadprogram <ron@hybridgroup.com>
Date: Sat, 6 Jan 2024 19:07:18 +0100
Subject: [PATCH] ninafw: add support for software RTS/CTS flow control for
 boards where hardware support is not available

Signed-off-by: deadprogram <ron@hybridgroup.com>
---
 adapter_ninafw.go | 27 +++++++++++++++++++++------
 hci_ninafw.go     | 46 ++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 63 insertions(+), 10 deletions(-)

diff --git a/adapter_ninafw.go b/adapter_ninafw.go
index 7ff3c05..c246b2c 100644
--- a/adapter_ninafw.go
+++ b/adapter_ninafw.go
@@ -41,7 +41,6 @@ var DefaultAdapter = &Adapter{
 func (a *Adapter) Enable() error {
 	// reset the NINA in BLE mode
 	machine.NINA_CS.Configure(machine.PinConfig{Mode: machine.PinOutput})
-	machine.NINA_RESETN.Configure(machine.PinConfig{Mode: machine.PinOutput})
 	machine.NINA_CS.Low()
 
 	if machine.NINA_RESET_INVERTED {
@@ -51,16 +50,28 @@ func (a *Adapter) Enable() error {
 	}
 
 	// serial port for nina chip
-	uart := machine.UART1
-	uart.Configure(machine.UARTConfig{
+	uart := machine.UART_NINA
+	cfg := machine.UARTConfig{
 		TX:       machine.NINA_TX,
 		RX:       machine.NINA_RX,
 		BaudRate: machine.NINA_BAUDRATE,
-		CTS:      machine.NINA_CTS,
-		RTS:      machine.NINA_RTS,
-	})
+	}
+	if !machine.NINA_SOFT_FLOWCONTROL {
+		cfg.CTS = machine.NINA_CTS
+		cfg.RTS = machine.NINA_RTS
+	}
+
+	uart.Configure(cfg)
 
 	a.hci, a.att = newBLEStack(uart)
+	if machine.NINA_SOFT_FLOWCONTROL {
+		a.hci.softRTS = machine.NINA_RTS
+		a.hci.softRTS.Configure(machine.PinConfig{Mode: machine.PinOutput})
+		a.hci.softRTS.High()
+
+		a.hci.softCTS = machine.NINA_CTS
+		machine.NINA_CTS.Configure(machine.PinConfig{Mode: machine.PinInput})
+	}
 
 	a.hci.start()
 
@@ -122,6 +133,8 @@ func makeNINAAddress(mac MAC) [6]uint8 {
 }
 
 func resetNINA() {
+	machine.NINA_RESETN.Configure(machine.PinConfig{Mode: machine.PinOutput})
+
 	machine.NINA_RESETN.High()
 	time.Sleep(100 * time.Millisecond)
 	machine.NINA_RESETN.Low()
@@ -129,6 +142,8 @@ func resetNINA() {
 }
 
 func resetNINAInverted() {
+	machine.NINA_RESETN.Configure(machine.PinConfig{Mode: machine.PinOutput})
+
 	machine.NINA_RESETN.Low()
 	time.Sleep(100 * time.Millisecond)
 	machine.NINA_RESETN.High()
diff --git a/hci_ninafw.go b/hci_ninafw.go
index 4b1db95..7952e8a 100644
--- a/hci_ninafw.go
+++ b/hci_ninafw.go
@@ -117,6 +117,8 @@ type leConnectData struct {
 
 type hci struct {
 	uart              *machine.UART
+	softCTS           machine.Pin
+	softRTS           machine.Pin
 	att               *att
 	buf               []byte
 	address           [6]byte
@@ -129,12 +131,21 @@ type hci struct {
 }
 
 func newHCI(uart *machine.UART) *hci {
-	return &hci{uart: uart,
-		buf: make([]byte, 256),
+	return &hci{
+		uart:    uart,
+		softCTS: machine.NoPin,
+		softRTS: machine.NoPin,
+		buf:     make([]byte, 256),
 	}
 }
 
 func (h *hci) start() error {
+	if h.softRTS != machine.NoPin {
+		h.softRTS.Low()
+
+		defer h.softRTS.High()
+	}
+
 	for h.uart.Buffered() > 0 {
 		h.uart.ReadByte()
 	}
@@ -151,6 +162,12 @@ func (h *hci) reset() error {
 }
 
 func (h *hci) poll() error {
+	if h.softRTS != machine.NoPin {
+		h.softRTS.Low()
+
+		defer h.softRTS.High()
+	}
+
 	i := 0
 	for h.uart.Buffered() > 0 {
 		data, _ := h.uart.ReadByte()
@@ -322,7 +339,7 @@ func (h *hci) sendCommandWithParams(opcode uint16, params []byte) error {
 	h.buf[3] = byte(len(params))
 	copy(h.buf[4:], params)
 
-	if _, err := h.uart.Write(h.buf[:4+len(params)]); err != nil {
+	if _, err := h.write(h.buf[:4+len(params)]); err != nil {
 		return err
 	}
 
@@ -356,13 +373,34 @@ func (h *hci) sendAclPkt(handle uint16, cid uint8, data []byte) error {
 		println("hci send acl data", handle, cid, hex.EncodeToString(h.buf[:9+len(data)]))
 	}
 
-	if _, err := h.uart.Write(h.buf[:9+len(data)]); err != nil {
+	if _, err := h.write(h.buf[:9+len(data)]); err != nil {
 		return err
 	}
 
 	return nil
 }
 
+const writeAttempts = 200
+
+func (h *hci) write(buf []byte) (int, error) {
+	if h.softCTS != machine.NoPin {
+		retries := writeAttempts
+		for h.softCTS.Get() {
+			retries--
+			if retries == 0 {
+				return 0, ErrHCITimeout
+			}
+		}
+	}
+
+	n, err := h.uart.Write(buf)
+	if err != nil {
+		return 0, err
+	}
+
+	return n, nil
+}
+
 type aclDataHeader struct {
 	handle uint16
 	dlen   uint16