Begin FTDI serial driver

USBHost_t36.h

 };
 
 
+class USBSerial: public USBDriver, public Stream {
+public:
+	enum { BUFFER_SIZE = 4200 }; // must hold at least 6 max size packets, plus 2 extra bytes
+	USBSerial(USBHost &host) { init(); }
+	void begin(uint32_t baud, uint32_t format=0);
+	void end(void);
+	virtual int available(void);
+	virtual int peek(void);
+	virtual int read(void);
+	virtual size_t write(uint8_t c);
+protected:
+	virtual bool claim(Device_t *device, int type, const uint8_t *descriptors, uint32_t len);
+	virtual void disconnect();
+private:
+	static void rx_callback(const Transfer_t *transfer);
+	static void tx_callback(const Transfer_t *transfer);
+	void rx_data(const Transfer_t *transfer);
+	void tx_data(const Transfer_t *transfer);
+	void init();
+	static bool check_rxtx_ep(uint32_t &rxep, uint32_t &txep);
+	bool init_buffers(uint32_t rsize, uint32_t tsize);
+private:
+	Pipe_t mypipes[3] __attribute__ ((aligned(32)));
+	Transfer_t mytransfers[7] __attribute__ ((aligned(32)));
+	uint32_t bigbuffer[(BUFFER_SIZE+3)/4];
+	Pipe_t *rxpipe;
+	Pipe_t *txpipe;
+	uint8_t *rx1;	// location for first incoming packet
+	uint8_t *rx2;	// location for second incoming packet
+	uint8_t *rxbuf;	// receive circular buffer
+	uint16_t rxhead;// receive head
+	uint16_t rxtail;// receive tail
+	uint8_t *tx1;	// location for first outgoing packet
+	uint8_t *tx2;	// location for second outgoing packet
+	uint8_t *txbuf;
+	uint16_t txhead;
+	uint16_t txtail;
+	uint16_t rxsize;// size of receive circular buffer
+	uint16_t txsize;// size of transmit circular buffer
+	uint8_t  rxstate;// bitmask: which receive packets are queued
+	bool     ignore_first_two_bytes;
+};
+
+
 class MouseController : public USBHIDInput {
 public:
 	MouseController(USBHost &host) { USBHIDParser::driver_ready_for_hid_collection(this); }

serial.cpp

+/* USB EHCI Host for Teensy 3.6
+ * Copyright 2017 Paul Stoffregen (paul@pjrc.com)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included
+ * in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <Arduino.h>
+#include "USBHost_t36.h"  // Read this header first for key info
+
+// quick hack - ultimately USBHost print & println need to be renamed
+#define print   USBHost::print
+#define println USBHost::println
+
+void USBSerial::init()
+{
+	contribute_Pipes(mypipes, sizeof(mypipes)/sizeof(Pipe_t));
+	contribute_Transfers(mytransfers, sizeof(mytransfers)/sizeof(Transfer_t));
+	driver_ready_for_device(this);
+}
+
+bool USBSerial::claim(Device_t *dev, int type, const uint8_t *descriptors, uint32_t len)
+{
+	// only claim at interface level
+	println("USBSerial claim this=", (uint32_t)this, HEX);
+	print("vid=", dev->idVendor, HEX);
+	println(", pid=", dev->idProduct, HEX);
+	if (type == 0) {
+		if (dev->idVendor == 0x0403 && dev->idProduct == 0x6001) {
+			// FTDI FT232
+			println("len = ", len);
+			if (len < 23) return false;
+			if (descriptors[0] != 9) return false; // length 9
+			if (descriptors[9] != 7) return false; // length 7
+			if (descriptors[10] != 5) return false; // ep desc
+			uint32_t rxep = descriptors[11];
+			if (descriptors[12] != 2) return false; // bulk type
+			if (descriptors[13] != 64) return false; // size 64
+			if (descriptors[14] != 0) return false;
+			if (descriptors[16] != 7) return false; // length 7
+			if (descriptors[17] != 5) return false; // ep desc
+			uint32_t txep = descriptors[18];
+			if (descriptors[19] != 2) return false; // bulk type
+			if (descriptors[20] != 64) return false; // size 64
+			if (descriptors[21] != 0) return false;
+			if (!check_rxtx_ep(rxep, txep)) return false;
+			print("FTDI, rxep=", rxep & 15);
+			println(", txep=", txep);
+			if (!init_buffers(64, 64)) return false;
+			rxpipe = new_Pipe(dev, 2, rxep & 15, 1, 64);
+			if (!rxpipe) return false;
+			txpipe = new_Pipe(dev, 2, txep, 0, 64);
+			if (!txpipe) {
+				// TODO: free rxpipe
+				return false;
+			}
+			ignore_first_two_bytes = true;
+			rxpipe->callback_function = rx_callback;
+			queue_Data_Transfer(rxpipe, rx1, 64, this);
+			rxstate = 1;
+			if (rxsize > 128) {
+				queue_Data_Transfer(rxpipe, rx2, 64, this);
+				rxstate = 3;
+			}
+			txpipe->callback_function = tx_callback;
+			return true;
+		}
+	}
+	return false;
+}
+
+// check if two legal endpoints, 1 receive & 1 transmit
+bool USBSerial::check_rxtx_ep(uint32_t &rxep, uint32_t &txep)
+{
+	if ((rxep & 0x0F) == 0) return false;
+	if ((txep & 0x0F) == 0) return false;
+	uint32_t rxdir = rxep & 0xF0;
+	uint32_t txdir = txep & 0xF0;
+	if (rxdir == 0x80 && txdir == 0x00) {
+		return true;
+	}
+	if (rxdir == 0x00 && txdir == 0x80) {
+		std::swap(rxep, txep);
+		return true;
+	}
+	return false;
+}
+
+// initialize buffer sizes and pointers
+bool USBSerial::init_buffers(uint32_t rsize, uint32_t tsize)
+{
+	// buffer must be able to hold 2 of each packet, plus have room to
+	if (sizeof(bigbuffer) < (rsize + tsize) * 3 + 2) return false;
+	rx1 = (uint8_t *)bigbuffer;
+	rx2 = rx1 + rsize;
+	tx1 = rx2 + rsize;
+	tx2 = tx1 + tsize;
+	rxbuf = tx2 + tsize;
+	// FIXME: this assume 50-50 split - not true when rsize != tsize
+	rxsize = (sizeof(bigbuffer) - (rsize + tsize) * 2) / 2;
+	txsize = rxsize;
+	txbuf = rxbuf + rxsize;
+	rxhead = 0;
+	rxtail = 0;
+	txhead = 0;
+	txtail = 0;
+	rxstate = 0;
+	return true;
+}
+
+
+
+
+
+
+
+void USBSerial::rx_callback(const Transfer_t *transfer)
+{
+	if (!transfer->driver) return;
+	((USBSerial *)(transfer->driver))->rx_data(transfer);
+}
+
+void USBSerial::tx_callback(const Transfer_t *transfer)
+{
+	if (!transfer->driver) return;
+	((USBSerial *)(transfer->driver))->tx_data(transfer);
+}
+
+void USBSerial::rx_data(const Transfer_t *transfer)
+{
+	uint32_t len = transfer->length - ((transfer->qtd.token >> 16) & 0x7FFF);
+	print("rx: ");
+	print_hexbytes(transfer->buffer, len);
+
+	// first update rxstate bitmask
+	if (transfer->buffer == rx1) {
+		rxstate &= 0xFE;
+	} else if (transfer->buffer == rx2) {
+		rxstate &= 0xFD;
+	}
+	// get start of data and actual length
+	const uint8_t *p = (const uint8_t *)transfer->buffer;
+	if (ignore_first_two_bytes) {
+		if (len >= 2) {
+			p += 2;
+			len -= 2;
+		} else {
+			len = 0;
+		}
+	}
+	// copy data from packet buffer to circular buffer
+	if (len > 0) {
+		// TODO: copy to buffer
+	}
+	// re-queue packet buffer(s) if possible
+	uint32_t avail;
+	uint32_t head = rxhead;
+	uint32_t tail = rxtail;
+	if (head >= tail) {
+		avail = rxsize - 1 + (tail - head);
+	} else {
+		avail = (tail - head) - 1;
+	}
+	uint32_t packetsize = rx2 - rx1;
+	if (avail >= packetsize) {
+		if ((rxstate & 0x01) == 0) {
+			queue_Data_Transfer(rxpipe, rx1, packetsize, this);
+			rxstate |= 0x01;
+		} else if ((rxstate & 0x02) == 0) {
+			queue_Data_Transfer(rxpipe, rx2, packetsize, this);
+			rxstate |= 0x02;
+		}
+		if ((rxstate & 0x03) != 0x03 && avail >= packetsize * 2) {
+			if ((rxstate & 0x01) == 0) {
+				queue_Data_Transfer(rxpipe, rx1, packetsize, this);
+				rxstate |= 0x01;
+			} else if ((rxstate & 0x02) == 0) {
+				queue_Data_Transfer(rxpipe, rx2, packetsize, this);
+				rxstate |= 0x02;
+			}
+		}
+	}
+}
+
+void USBSerial::tx_data(const Transfer_t *transfer)
+{
+	println("tx: ");
+}
+
+
+
+
+
+
+
+void USBSerial::begin(uint32_t baud, uint32_t format)
+{
+}
+
+void USBSerial::end(void)
+{
+}
+
+int USBSerial::available(void)
+{
+	return 0;
+}
+
+int USBSerial::peek(void)
+{
+	return -1;
+}
+
+int USBSerial::read(void)
+{
+	return -1;
+}
+
+size_t USBSerial::write(uint8_t c)
+{
+	return 1;
+}
+
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+
+void USBSerial::disconnect()
+{
+}
+
+