xref: /linux/drivers/usb/serial/quatech2.c (revision ce7240e445303de3ca66e6d08f17a2ec278a5bf6)
1 /*
2  * usb-serial driver for Quatech USB 2 devices
3  *
4  * Copyright (C) 2012 Bill Pemberton (wfp5p@virginia.edu)
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License version 2
8  * as published by the Free Software Foundation.
9  *
10  *
11  *  These devices all have only 1 bulk in and 1 bulk out that is shared
12  *  for all serial ports.
13  *
14  */
15 
16 #include <asm/unaligned.h>
17 #include <linux/errno.h>
18 #include <linux/init.h>
19 #include <linux/slab.h>
20 #include <linux/tty.h>
21 #include <linux/tty_driver.h>
22 #include <linux/tty_flip.h>
23 #include <linux/module.h>
24 #include <linux/serial.h>
25 #include <linux/usb.h>
26 #include <linux/usb/serial.h>
27 #include <linux/serial_reg.h>
28 #include <linux/uaccess.h>
29 
30 static bool debug;
31 
32 /* default urb timeout for usb operations */
33 #define QT2_USB_TIMEOUT USB_CTRL_SET_TIMEOUT
34 
35 #define QT_OPEN_CLOSE_CHANNEL       0xca
36 #define QT_SET_GET_DEVICE           0xc2
37 #define QT_SET_GET_REGISTER         0xc0
38 #define QT_GET_SET_PREBUF_TRIG_LVL  0xcc
39 #define QT_SET_ATF                  0xcd
40 #define QT_TRANSFER_IN              0xc0
41 #define QT_HW_FLOW_CONTROL_MASK     0xc5
42 #define QT_SW_FLOW_CONTROL_MASK     0xc6
43 #define QT2_BREAK_CONTROL	    0xc8
44 #define QT2_GET_SET_UART            0xc1
45 #define QT2_FLUSH_DEVICE	    0xc4
46 #define QT2_GET_SET_QMCR            0xe1
47 #define QT2_QMCR_RS232              0x40
48 #define QT2_QMCR_RS422              0x10
49 
50 #define  SERIAL_CRTSCTS ((UART_MCR_RTS << 8) | UART_MSR_CTS)
51 
52 #define  SERIAL_EVEN_PARITY         (UART_LCR_PARITY | UART_LCR_EPAR)
53 
54 /* status bytes for the device */
55 #define QT2_CONTROL_BYTE    0x1b
56 #define QT2_LINE_STATUS     0x00  /* following 1 byte is line status */
57 #define QT2_MODEM_STATUS    0x01  /* following 1 byte is modem status */
58 #define QT2_XMIT_HOLD       0x02  /* following 2 bytes are ?? */
59 #define QT2_CHANGE_PORT     0x03  /* following 1 byte is port to change to */
60 #define QT2_REC_FLUSH       0x04  /* no following info */
61 #define QT2_XMIT_FLUSH      0x05  /* no following info */
62 #define QT2_CONTROL_ESCAPE  0xff  /* pass through previous 2 control bytes */
63 
64 #define  MAX_BAUD_RATE              921600
65 #define  DEFAULT_BAUD_RATE          9600
66 
67 #define QT2_WRITE_BUFFER_SIZE   512  /* size of write buffer */
68 #define QT2_WRITE_CONTROL_SIZE  5    /* control bytes used for a write */
69 
70 /* Version Information */
71 #define DRIVER_VERSION "v0.1"
72 #define DRIVER_DESC "Quatech 2nd gen USB to Serial Driver"
73 
74 #define	USB_VENDOR_ID_QUATECH	0x061d
75 #define QUATECH_SSU2_100	0xC120	/* RS232 single port */
76 #define QUATECH_DSU2_100	0xC140	/* RS232 dual port */
77 #define QUATECH_DSU2_400	0xC150	/* RS232/422/485 dual port */
78 #define QUATECH_QSU2_100	0xC160	/* RS232 four port */
79 #define QUATECH_QSU2_400	0xC170	/* RS232/422/485 four port */
80 #define QUATECH_ESU2_100	0xC1A0	/* RS232 eight port */
81 #define QUATECH_ESU2_400	0xC180	/* RS232/422/485 eight port */
82 
83 struct qt2_device_detail {
84 	int product_id;
85 	int num_ports;
86 };
87 
88 #define QT_DETAILS(prod, ports)	\
89 	.product_id = (prod),   \
90 	.num_ports = (ports)
91 
92 static const struct qt2_device_detail qt2_device_details[] = {
93 	{QT_DETAILS(QUATECH_SSU2_100, 1)},
94 	{QT_DETAILS(QUATECH_DSU2_400, 2)},
95 	{QT_DETAILS(QUATECH_DSU2_100, 2)},
96 	{QT_DETAILS(QUATECH_QSU2_400, 4)},
97 	{QT_DETAILS(QUATECH_QSU2_100, 4)},
98 	{QT_DETAILS(QUATECH_ESU2_400, 8)},
99 	{QT_DETAILS(QUATECH_ESU2_100, 8)},
100 	{QT_DETAILS(0, 0)}	/* Terminating entry */
101 };
102 
103 static const struct usb_device_id id_table[] = {
104 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_SSU2_100)},
105 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_DSU2_100)},
106 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_DSU2_400)},
107 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_QSU2_100)},
108 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_QSU2_400)},
109 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_ESU2_100)},
110 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_ESU2_400)},
111 	{}			/* Terminating entry */
112 };
113 MODULE_DEVICE_TABLE(usb, id_table);
114 
115 struct qt2_serial_private {
116 	unsigned char current_port;  /* current port for incoming data */
117 
118 	struct urb	*read_urb;   /* shared among all ports */
119 	char		read_buffer[512];
120 };
121 
122 struct qt2_port_private {
123 	bool is_open;
124 	u8   device_port;
125 
126 	spinlock_t urb_lock;
127 	bool       urb_in_use;
128 	struct urb *write_urb;
129 	char       write_buffer[QT2_WRITE_BUFFER_SIZE];
130 
131 	spinlock_t  lock;
132 	u8          shadowLSR;
133 	u8          shadowMSR;
134 
135 	wait_queue_head_t   delta_msr_wait; /* Used for TIOCMIWAIT */
136 	struct async_icount icount;
137 
138 	struct usb_serial_port *port;
139 };
140 
141 static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch);
142 static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch);
143 static void qt2_write_bulk_callback(struct urb *urb);
144 static void qt2_read_bulk_callback(struct urb *urb);
145 
146 static void qt2_release(struct usb_serial *serial)
147 {
148 	int i;
149 
150 	kfree(usb_get_serial_data(serial));
151 
152 	for (i = 0; i < serial->num_ports; i++)
153 		kfree(usb_get_serial_port_data(serial->port[i]));
154 }
155 
156 static inline int calc_baud_divisor(int baudrate)
157 {
158 	int divisor, rem;
159 
160 	divisor = MAX_BAUD_RATE / baudrate;
161 	rem = MAX_BAUD_RATE % baudrate;
162 	/* Round to nearest divisor */
163 	if (((rem * 2) >= baudrate) && (baudrate != 110))
164 		divisor++;
165 
166 	return divisor;
167 }
168 
169 static inline int qt2_set_port_config(struct usb_device *dev,
170 				      unsigned char port_number,
171 				      u16 baudrate, u16 lcr)
172 {
173 	int divisor = calc_baud_divisor(baudrate);
174 	u16 index = ((u16) (lcr << 8) | (u16) (port_number));
175 
176 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
177 			       QT2_GET_SET_UART, 0x40,
178 			       divisor, index, NULL, 0, QT2_USB_TIMEOUT);
179 }
180 
181 static inline int qt2_control_msg(struct usb_device *dev,
182 				  u8 request, u16 data, u16 index)
183 {
184 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
185 			       request, 0x40, data, index,
186 			       NULL, 0, QT2_USB_TIMEOUT);
187 }
188 
189 static inline int qt2_setdevice(struct usb_device *dev, u8 *data)
190 {
191 	u16 x = ((u16) (data[1] << 8) | (u16) (data[0]));
192 
193 	return qt2_control_msg(dev, QT_SET_GET_DEVICE, x, 0);
194 }
195 
196 
197 static inline int qt2_getdevice(struct usb_device *dev, u8 *data)
198 {
199 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
200 			       QT_SET_GET_DEVICE, 0xc0, 0, 0,
201 			       data, 3, QT2_USB_TIMEOUT);
202 }
203 
204 static inline int qt2_getregister(struct usb_device *dev,
205 				  u8 uart,
206 				  u8 reg,
207 				  u8 *data)
208 {
209 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
210 			       QT_SET_GET_REGISTER, 0xc0, reg,
211 			       uart, data, sizeof(*data), QT2_USB_TIMEOUT);
212 
213 }
214 
215 static inline int qt2_setregister(struct usb_device *dev,
216 				  u8 uart, u8 reg, u16 data)
217 {
218 	u16 value = (data << 8) | reg;
219 
220 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
221 			       QT_SET_GET_REGISTER, 0x40, value, uart,
222 			       NULL, 0, QT2_USB_TIMEOUT);
223 }
224 
225 static inline int update_mctrl(struct qt2_port_private *port_priv,
226 			       unsigned int set, unsigned int clear)
227 {
228 	struct usb_serial_port *port = port_priv->port;
229 	struct usb_device *dev = port->serial->dev;
230 	unsigned urb_value;
231 	int status;
232 
233 	if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) {
234 		dev_dbg(&port->dev,
235 			"update_mctrl - DTR|RTS not being set|cleared\n");
236 		return 0;	/* no change */
237 	}
238 
239 	clear &= ~set;	/* 'set' takes precedence over 'clear' */
240 	urb_value = 0;
241 	if (set & TIOCM_DTR)
242 		urb_value |= UART_MCR_DTR;
243 	if (set & TIOCM_RTS)
244 		urb_value |= UART_MCR_RTS;
245 
246 	status = qt2_setregister(dev, port_priv->device_port, UART_MCR,
247 				 urb_value);
248 	if (status < 0)
249 		dev_err(&port->dev,
250 			"update_mctrl - Error from MODEM_CTRL urb: %i\n",
251 			status);
252 	return status;
253 }
254 
255 static int qt2_calc_num_ports(struct usb_serial *serial)
256 {
257 	struct qt2_device_detail d;
258 	int i;
259 
260 	for (i = 0; d = qt2_device_details[i], d.product_id != 0; i++) {
261 		if (d.product_id == le16_to_cpu(serial->dev->descriptor.idProduct))
262 			return d.num_ports;
263 	}
264 
265 	/* we didn't recognize the device */
266 	dev_err(&serial->dev->dev,
267 		 "don't know the number of ports, assuming 1\n");
268 
269 	return 1;
270 }
271 
272 static void qt2_set_termios(struct tty_struct *tty,
273 			    struct usb_serial_port *port,
274 			    struct ktermios *old_termios)
275 {
276 	struct usb_device *dev = port->serial->dev;
277 	struct qt2_port_private *port_priv;
278 	struct ktermios *termios = &tty->termios;
279 	u16 baud;
280 	unsigned int cflag = termios->c_cflag;
281 	u16 new_lcr = 0;
282 	int status;
283 
284 	port_priv = usb_get_serial_port_data(port);
285 
286 	if (cflag & PARENB) {
287 		if (cflag & PARODD)
288 			new_lcr |= UART_LCR_PARITY;
289 		else
290 			new_lcr |= SERIAL_EVEN_PARITY;
291 	}
292 
293 	switch (cflag & CSIZE) {
294 	case CS5:
295 		new_lcr |= UART_LCR_WLEN5;
296 		break;
297 	case CS6:
298 		new_lcr |= UART_LCR_WLEN6;
299 		break;
300 	case CS7:
301 		new_lcr |= UART_LCR_WLEN7;
302 		break;
303 	default:
304 	case CS8:
305 		new_lcr |= UART_LCR_WLEN8;
306 		break;
307 	}
308 
309 	baud = tty_get_baud_rate(tty);
310 	if (!baud)
311 		baud = 9600;
312 
313 	status = qt2_set_port_config(dev, port_priv->device_port, baud,
314 				     new_lcr);
315 	if (status < 0)
316 		dev_err(&port->dev, "%s - qt2_set_port_config failed: %i\n",
317 			__func__, status);
318 
319 	if (cflag & CRTSCTS)
320 		status = qt2_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
321 					 SERIAL_CRTSCTS,
322 					 port_priv->device_port);
323 	else
324 		status = qt2_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
325 					 0, port_priv->device_port);
326 	if (status < 0)
327 		dev_err(&port->dev, "%s - set HW flow control failed: %i\n",
328 			__func__, status);
329 
330 	if (I_IXOFF(tty) || I_IXON(tty)) {
331 		u16 x = ((u16) (START_CHAR(tty) << 8) | (u16) (STOP_CHAR(tty)));
332 
333 		status = qt2_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
334 					 x, port_priv->device_port);
335 	} else
336 		status = qt2_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
337 					 0, port_priv->device_port);
338 
339 	if (status < 0)
340 		dev_err(&port->dev, "%s - set SW flow control failed: %i\n",
341 			__func__, status);
342 
343 }
344 
345 static int qt2_open(struct tty_struct *tty, struct usb_serial_port *port)
346 {
347 	struct usb_serial *serial;
348 	struct qt2_serial_private *serial_priv;
349 	struct qt2_port_private *port_priv;
350 	u8 *data;
351 	u16 device_port;
352 	int status;
353 	unsigned long flags;
354 
355 	device_port = (u16) (port->number - port->serial->minor);
356 
357 	serial = port->serial;
358 
359 	port_priv = usb_get_serial_port_data(port);
360 	serial_priv = usb_get_serial_data(serial);
361 
362 	/* set the port to RS232 mode */
363 	status = qt2_control_msg(serial->dev, QT2_GET_SET_QMCR,
364 				 QT2_QMCR_RS232, device_port);
365 	if (status < 0) {
366 		dev_err(&port->dev,
367 			"%s failed to set RS232 mode for port %i error %i\n",
368 			__func__, device_port, status);
369 		return status;
370 	}
371 
372 	data = kzalloc(2, GFP_KERNEL);
373 	if (!data)
374 		return -ENOMEM;
375 
376 	/* open the port */
377 	status = usb_control_msg(serial->dev,
378 				 usb_rcvctrlpipe(serial->dev, 0),
379 				 QT_OPEN_CLOSE_CHANNEL,
380 				 0xc0, 0,
381 				 device_port, data, 2, QT2_USB_TIMEOUT);
382 
383 	if (status < 0) {
384 		dev_err(&port->dev, "%s - open port failed %i", __func__,
385 			status);
386 		kfree(data);
387 		return status;
388 	}
389 
390 	spin_lock_irqsave(&port_priv->lock, flags);
391 	port_priv->shadowLSR = data[0];
392 	port_priv->shadowMSR = data[1];
393 	spin_unlock_irqrestore(&port_priv->lock, flags);
394 
395 	kfree(data);
396 
397 	/* set to default speed and 8bit word size */
398 	status = qt2_set_port_config(serial->dev, device_port,
399 				     DEFAULT_BAUD_RATE, UART_LCR_WLEN8);
400 	if (status < 0) {
401 		dev_err(&port->dev,
402 			"%s - initial setup failed for port %i (%i)\n",
403 			__func__, port->number, device_port);
404 		return status;
405 	}
406 
407 	port_priv->is_open = true;
408 	port_priv->device_port = (u8) device_port;
409 
410 	if (tty)
411 		qt2_set_termios(tty, port, &tty->termios);
412 
413 	return 0;
414 
415 }
416 
417 static void qt2_close(struct usb_serial_port *port)
418 {
419 	struct usb_serial *serial;
420 	struct qt2_serial_private *serial_priv;
421 	struct qt2_port_private *port_priv;
422 	unsigned long flags;
423 	int i;
424 
425 	serial = port->serial;
426 	serial_priv = usb_get_serial_data(serial);
427 	port_priv = usb_get_serial_port_data(port);
428 
429 	port_priv->is_open = false;
430 
431 	spin_lock_irqsave(&port_priv->urb_lock, flags);
432 	if (port_priv->write_urb->status == -EINPROGRESS)
433 		usb_kill_urb(port_priv->write_urb);
434 	port_priv->urb_in_use = false;
435 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
436 
437 	/* flush the port transmit buffer */
438 	i = usb_control_msg(serial->dev,
439 			    usb_rcvctrlpipe(serial->dev, 0),
440 			    QT2_FLUSH_DEVICE, 0x40, 1,
441 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
442 
443 	if (i < 0)
444 		dev_err(&port->dev, "%s - transmit buffer flush failed: %i\n",
445 			__func__, i);
446 
447 	/* flush the port receive buffer */
448 	i = usb_control_msg(serial->dev,
449 			    usb_rcvctrlpipe(serial->dev, 0),
450 			    QT2_FLUSH_DEVICE, 0x40, 0,
451 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
452 
453 	if (i < 0)
454 		dev_err(&port->dev, "%s - receive buffer flush failed: %i\n",
455 			__func__, i);
456 
457 	/* close the port */
458 	i = usb_control_msg(serial->dev,
459 			    usb_sndctrlpipe(serial->dev, 0),
460 			    QT_OPEN_CLOSE_CHANNEL,
461 			    0x40, 0,
462 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
463 
464 	if (i < 0)
465 		dev_err(&port->dev, "%s - close port failed %i\n",
466 			__func__, i);
467 
468 }
469 
470 static void qt2_disconnect(struct usb_serial *serial)
471 {
472 	struct qt2_serial_private *serial_priv = usb_get_serial_data(serial);
473 	struct qt2_port_private *port_priv;
474 	int i;
475 
476 	if (serial_priv->read_urb->status == -EINPROGRESS)
477 		usb_kill_urb(serial_priv->read_urb);
478 
479 	usb_free_urb(serial_priv->read_urb);
480 
481 	for (i = 0; i < serial->num_ports; i++) {
482 		port_priv = usb_get_serial_port_data(serial->port[i]);
483 
484 		if (port_priv->write_urb->status == -EINPROGRESS)
485 			usb_kill_urb(port_priv->write_urb);
486 		usb_free_urb(port_priv->write_urb);
487 	}
488 }
489 
490 static int get_serial_info(struct usb_serial_port *port,
491 			   struct serial_struct __user *retinfo)
492 {
493 	struct serial_struct tmp;
494 
495 	if (!retinfo)
496 		return -EFAULT;
497 
498 	memset(&tmp, 0, sizeof(tmp));
499 	tmp.line		= port->serial->minor;
500 	tmp.port		= 0;
501 	tmp.irq			= 0;
502 	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
503 	tmp.xmit_fifo_size	= port->bulk_out_size;
504 	tmp.baud_base		= 9600;
505 	tmp.close_delay		= 5*HZ;
506 	tmp.closing_wait	= 30*HZ;
507 
508 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
509 		return -EFAULT;
510 	return 0;
511 }
512 
513 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
514 {
515 	struct qt2_port_private *priv = usb_get_serial_port_data(port);
516 	struct async_icount prev, cur;
517 	unsigned long flags;
518 
519 	spin_lock_irqsave(&priv->lock, flags);
520 	prev = priv->icount;
521 	spin_unlock_irqrestore(&priv->lock, flags);
522 
523 	while (1) {
524 		wait_event_interruptible(priv->delta_msr_wait,
525 					 ((priv->icount.rng != prev.rng) ||
526 					  (priv->icount.dsr != prev.dsr) ||
527 					  (priv->icount.dcd != prev.dcd) ||
528 					  (priv->icount.cts != prev.cts)));
529 
530 		if (signal_pending(current))
531 			return -ERESTARTSYS;
532 
533 		spin_lock_irqsave(&priv->lock, flags);
534 		cur = priv->icount;
535 		spin_unlock_irqrestore(&priv->lock, flags);
536 
537 		if ((prev.rng == cur.rng) &&
538 		    (prev.dsr == cur.dsr) &&
539 		    (prev.dcd == cur.dcd) &&
540 		    (prev.cts == cur.cts))
541 			return -EIO;
542 
543 		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
544 		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
545 		    (arg & TIOCM_CD && (prev.dcd != cur.dcd)) ||
546 		    (arg & TIOCM_CTS && (prev.cts != cur.cts)))
547 			return 0;
548 	}
549 	return 0;
550 }
551 
552 static int qt2_get_icount(struct tty_struct *tty,
553 			  struct serial_icounter_struct *icount)
554 {
555 	struct usb_serial_port *port = tty->driver_data;
556 	struct qt2_port_private *priv = usb_get_serial_port_data(port);
557 	struct async_icount cnow = priv->icount;
558 
559 	icount->cts = cnow.cts;
560 	icount->dsr = cnow.dsr;
561 	icount->rng = cnow.rng;
562 	icount->dcd = cnow.dcd;
563 	icount->rx = cnow.rx;
564 	icount->tx = cnow.tx;
565 	icount->frame = cnow.frame;
566 	icount->overrun = cnow.overrun;
567 	icount->parity = cnow.parity;
568 	icount->brk = cnow.brk;
569 	icount->buf_overrun = cnow.buf_overrun;
570 
571 	return 0;
572 }
573 
574 static int qt2_ioctl(struct tty_struct *tty,
575 		     unsigned int cmd, unsigned long arg)
576 {
577 	struct usb_serial_port *port = tty->driver_data;
578 
579 	switch (cmd) {
580 	case TIOCGSERIAL:
581 		return get_serial_info(port,
582 				       (struct serial_struct __user *)arg);
583 
584 	case TIOCMIWAIT:
585 		return wait_modem_info(port, arg);
586 
587 	default:
588 		break;
589 	}
590 
591 	return -ENOIOCTLCMD;
592 }
593 
594 static void qt2_process_status(struct usb_serial_port *port, unsigned char *ch)
595 {
596 	switch (*ch) {
597 	case QT2_LINE_STATUS:
598 		qt2_update_lsr(port, ch + 1);
599 		break;
600 	case QT2_MODEM_STATUS:
601 		qt2_update_msr(port, ch + 1);
602 		break;
603 	}
604 }
605 
606 /* not needed, kept to document functionality */
607 static void qt2_process_xmit_empty(struct usb_serial_port *port,
608 				   unsigned char *ch)
609 {
610 	int bytes_written;
611 
612 	bytes_written = (int)(*ch) + (int)(*(ch + 1) << 4);
613 }
614 
615 /* not needed, kept to document functionality */
616 static void qt2_process_flush(struct usb_serial_port *port, unsigned char *ch)
617 {
618 	return;
619 }
620 
621 void qt2_process_read_urb(struct urb *urb)
622 {
623 	struct usb_serial *serial;
624 	struct qt2_serial_private *serial_priv;
625 	struct usb_serial_port *port;
626 	struct qt2_port_private *port_priv;
627 	struct tty_struct *tty;
628 	bool escapeflag;
629 	unsigned char *ch;
630 	int i;
631 	unsigned char newport;
632 	int len = urb->actual_length;
633 
634 	if (!len)
635 		return;
636 
637 	ch = urb->transfer_buffer;
638 	tty = NULL;
639 	serial = urb->context;
640 	serial_priv = usb_get_serial_data(serial);
641 	port = serial->port[serial_priv->current_port];
642 	port_priv = usb_get_serial_port_data(port);
643 
644 	if (port_priv->is_open)
645 		tty = tty_port_tty_get(&port->port);
646 
647 	for (i = 0; i < urb->actual_length; i++) {
648 		ch = (unsigned char *)urb->transfer_buffer + i;
649 		if ((i <= (len - 3)) &&
650 		    (*ch == QT2_CONTROL_BYTE) &&
651 		    (*(ch + 1) == QT2_CONTROL_BYTE)) {
652 			escapeflag = false;
653 			switch (*(ch + 2)) {
654 			case QT2_LINE_STATUS:
655 			case QT2_MODEM_STATUS:
656 				if (i > (len - 4)) {
657 					dev_warn(&port->dev,
658 						 "%s - status message too short\n",
659 						__func__);
660 					break;
661 				}
662 				qt2_process_status(port, ch + 2);
663 				i += 3;
664 				escapeflag = true;
665 				break;
666 			case QT2_XMIT_HOLD:
667 				if (i > (len - 5)) {
668 					dev_warn(&port->dev,
669 						 "%s - xmit_empty message too short\n",
670 						 __func__);
671 					break;
672 				}
673 				qt2_process_xmit_empty(port, ch + 3);
674 				i += 4;
675 				escapeflag = true;
676 				break;
677 			case QT2_CHANGE_PORT:
678 				if (i > (len - 4)) {
679 					dev_warn(&port->dev,
680 						 "%s - change_port message too short\n",
681 						 __func__);
682 					break;
683 				}
684 				if (tty) {
685 					tty_flip_buffer_push(tty);
686 					tty_kref_put(tty);
687 				}
688 
689 				newport = *(ch + 3);
690 
691 				if (newport > serial->num_ports) {
692 					dev_err(&port->dev,
693 						"%s - port change to invalid port: %i\n",
694 						__func__, newport);
695 					break;
696 				}
697 
698 				serial_priv->current_port = newport;
699 				port = serial->port[serial_priv->current_port];
700 				port_priv = usb_get_serial_port_data(port);
701 				if (port_priv->is_open)
702 					tty = tty_port_tty_get(&port->port);
703 				else
704 					tty = NULL;
705 				i += 3;
706 				escapeflag = true;
707 				break;
708 			case QT2_REC_FLUSH:
709 			case QT2_XMIT_FLUSH:
710 				qt2_process_flush(port, ch + 2);
711 				i += 2;
712 				escapeflag = true;
713 				break;
714 			case QT2_CONTROL_ESCAPE:
715 				tty_buffer_request_room(tty, 2);
716 				tty_insert_flip_string(tty, ch, 2);
717 				i += 2;
718 				escapeflag = true;
719 				break;
720 			default:
721 				dev_warn(&port->dev,
722 					 "%s - unsupported command %i\n",
723 					 __func__, *(ch + 2));
724 				break;
725 			}
726 			if (escapeflag)
727 				continue;
728 		}
729 
730 		if (tty) {
731 			tty_buffer_request_room(tty, 1);
732 			tty_insert_flip_string(tty, ch, 1);
733 		}
734 	}
735 
736 	if (tty) {
737 		tty_flip_buffer_push(tty);
738 		tty_kref_put(tty);
739 	}
740 }
741 
742 static void qt2_write_bulk_callback(struct urb *urb)
743 {
744 	struct usb_serial_port *port;
745 	struct qt2_port_private *port_priv;
746 
747 	port = urb->context;
748 	port_priv = usb_get_serial_port_data(port);
749 
750 	spin_lock(&port_priv->urb_lock);
751 
752 	port_priv->urb_in_use = false;
753 	usb_serial_port_softint(port);
754 
755 	spin_unlock(&port_priv->urb_lock);
756 
757 }
758 
759 static void qt2_read_bulk_callback(struct urb *urb)
760 {
761 	struct usb_serial *serial = urb->context;
762 	int status;
763 
764 	if (urb->status) {
765 		dev_warn(&serial->dev->dev,
766 			 "%s - non-zero urb status: %i\n", __func__,
767 			 urb->status);
768 		return;
769 	}
770 
771 	qt2_process_read_urb(urb);
772 
773 	status = usb_submit_urb(urb, GFP_ATOMIC);
774 	if (status != 0)
775 		dev_err(&serial->dev->dev,
776 			"%s - resubmit read urb failed: %i\n",
777 			__func__, status);
778 }
779 
780 static int qt2_setup_urbs(struct usb_serial *serial)
781 {
782 	struct usb_serial_port *port;
783 	struct usb_serial_port *port0;
784 	struct qt2_serial_private *serial_priv;
785 	struct qt2_port_private *port_priv;
786 	int pcount, status;
787 
788 	port0 = serial->port[0];
789 
790 	serial_priv = usb_get_serial_data(serial);
791 	serial_priv->read_urb = usb_alloc_urb(0, GFP_KERNEL);
792 	if (!serial_priv->read_urb) {
793 		dev_err(&serial->dev->dev, "No free urbs available\n");
794 		return -ENOMEM;
795 	}
796 
797 	usb_fill_bulk_urb(serial_priv->read_urb, serial->dev,
798 			  usb_rcvbulkpipe(serial->dev,
799 					  port0->bulk_in_endpointAddress),
800 			  serial_priv->read_buffer,
801 			  sizeof(serial_priv->read_buffer),
802 			  qt2_read_bulk_callback, serial);
803 
804 	/* setup write_urb for each port */
805 	for (pcount = 0; pcount < serial->num_ports; pcount++) {
806 
807 		port = serial->port[pcount];
808 		port_priv = usb_get_serial_port_data(port);
809 
810 		port_priv->write_urb = usb_alloc_urb(0, GFP_KERNEL);
811 		if (!port_priv->write_urb) {
812 			dev_err(&serial->dev->dev,
813 				"failed to alloc write_urb for port %i\n",
814 				pcount);
815 			return -ENOMEM;
816 		}
817 
818 		usb_fill_bulk_urb(port_priv->write_urb,
819 				  serial->dev,
820 				  usb_sndbulkpipe(serial->dev,
821 						  port0->
822 						  bulk_out_endpointAddress),
823 				  port_priv->write_buffer,
824 				  sizeof(port_priv->write_buffer),
825 				  qt2_write_bulk_callback, port);
826 	}
827 
828 	status = usb_submit_urb(serial_priv->read_urb, GFP_KERNEL);
829 	if (status != 0) {
830 		dev_err(&serial->dev->dev,
831 			"%s - submit read urb failed %i\n", __func__, status);
832 		return status;
833 	}
834 
835 	return 0;
836 
837 }
838 
839 static int qt2_attach(struct usb_serial *serial)
840 {
841 	struct qt2_serial_private *serial_priv;
842 	struct qt2_port_private *port_priv;
843 	int status, pcount;
844 
845 	/* power on unit */
846 	status = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
847 				 0xc2, 0x40, 0x8000, 0, NULL, 0,
848 				 QT2_USB_TIMEOUT);
849 	if (status < 0) {
850 		dev_err(&serial->dev->dev,
851 			"%s - failed to power on unit: %i\n", __func__, status);
852 		return status;
853 	}
854 
855 	serial_priv = kzalloc(sizeof(*serial_priv), GFP_KERNEL);
856 	if (!serial_priv) {
857 		dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
858 		return -ENOMEM;
859 	}
860 
861 	usb_set_serial_data(serial, serial_priv);
862 
863 	for (pcount = 0; pcount < serial->num_ports; pcount++) {
864 		port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
865 		if (!port_priv) {
866 			dev_err(&serial->dev->dev,
867 				"%s- kmalloc(%Zd) failed.\n", __func__,
868 				sizeof(*port_priv));
869 			pcount--;
870 			status = -ENOMEM;
871 			goto attach_failed;
872 		}
873 
874 		spin_lock_init(&port_priv->lock);
875 		spin_lock_init(&port_priv->urb_lock);
876 		init_waitqueue_head(&port_priv->delta_msr_wait);
877 
878 		port_priv->port = serial->port[pcount];
879 
880 		usb_set_serial_port_data(serial->port[pcount], port_priv);
881 	}
882 
883 	status = qt2_setup_urbs(serial);
884 	if (status != 0)
885 		goto attach_failed;
886 
887 	return 0;
888 
889 attach_failed:
890 	for (/* empty */; pcount >= 0; pcount--) {
891 		port_priv = usb_get_serial_port_data(serial->port[pcount]);
892 		kfree(port_priv);
893 	}
894 	kfree(serial_priv);
895 	return status;
896 }
897 
898 static int qt2_tiocmget(struct tty_struct *tty)
899 {
900 	struct usb_serial_port *port = tty->driver_data;
901 	struct usb_device *dev = port->serial->dev;
902 	struct qt2_port_private *port_priv = usb_get_serial_port_data(port);
903 	u8 *d;
904 	int r;
905 
906 	d = kzalloc(2, GFP_KERNEL);
907 	if (!d)
908 		return -ENOMEM;
909 
910 	r = qt2_getregister(dev, port_priv->device_port, UART_MCR, d);
911 	if (r < 0)
912 		goto mget_out;
913 
914 	r = qt2_getregister(dev, port_priv->device_port, UART_MSR, d + 1);
915 	if (r < 0)
916 		goto mget_out;
917 
918 	r = (d[0] & UART_MCR_DTR ? TIOCM_DTR : 0) |
919 	    (d[0] & UART_MCR_RTS ? TIOCM_RTS : 0) |
920 	    (d[1] & UART_MSR_CTS ? TIOCM_CTS : 0) |
921 	    (d[1] & UART_MSR_DCD ? TIOCM_CAR : 0) |
922 	    (d[1] & UART_MSR_RI ? TIOCM_RI : 0) |
923 	    (d[1] & UART_MSR_DSR ? TIOCM_DSR : 0);
924 
925 mget_out:
926 	kfree(d);
927 	return r;
928 }
929 
930 static int qt2_tiocmset(struct tty_struct *tty,
931 			unsigned int set, unsigned int clear)
932 {
933 	struct qt2_port_private *port_priv;
934 
935 	port_priv = usb_get_serial_port_data(tty->driver_data);
936 	return update_mctrl(port_priv, set, clear);
937 }
938 
939 static void qt2_break_ctl(struct tty_struct *tty, int break_state)
940 {
941 	struct usb_serial_port *port = tty->driver_data;
942 	struct qt2_port_private *port_priv;
943 	int status;
944 	u16 val;
945 
946 	port_priv = usb_get_serial_port_data(port);
947 
948 	if (!port_priv->is_open) {
949 		dev_err(&port->dev,
950 			"%s - port is not open\n", __func__);
951 		return;
952 	}
953 
954 	val = (break_state == -1) ? 1 : 0;
955 
956 	status = qt2_control_msg(port->serial->dev, QT2_BREAK_CONTROL,
957 				 val, port_priv->device_port);
958 	if (status < 0)
959 		dev_warn(&port->dev,
960 			 "%s - failed to send control message: %i\n", __func__,
961 			 status);
962 }
963 
964 
965 
966 static void qt2_dtr_rts(struct usb_serial_port *port, int on)
967 {
968 	struct usb_device *dev = port->serial->dev;
969 	struct qt2_port_private *port_priv = usb_get_serial_port_data(port);
970 
971 	mutex_lock(&port->serial->disc_mutex);
972 	if (!port->serial->disconnected) {
973 		/* Disable flow control */
974 		if (!on && qt2_setregister(dev, port_priv->device_port,
975 					   UART_MCR, 0) < 0)
976 			dev_warn(&port->dev, "error from flowcontrol urb\n");
977 		/* drop RTS and DTR */
978 		if (on)
979 			update_mctrl(port_priv, TIOCM_DTR | TIOCM_RTS, 0);
980 		else
981 			update_mctrl(port_priv, 0, TIOCM_DTR | TIOCM_RTS);
982 	}
983 	mutex_unlock(&port->serial->disc_mutex);
984 }
985 
986 static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch)
987 {
988 	struct qt2_port_private *port_priv;
989 	u8 newMSR = (u8) *ch;
990 	unsigned long flags;
991 
992 	port_priv = usb_get_serial_port_data(port);
993 
994 	spin_lock_irqsave(&port_priv->lock, flags);
995 	port_priv->shadowMSR = newMSR;
996 	spin_unlock_irqrestore(&port_priv->lock, flags);
997 
998 	if (newMSR & UART_MSR_ANY_DELTA) {
999 		/* update input line counters */
1000 		if (newMSR & UART_MSR_DCTS)
1001 			port_priv->icount.cts++;
1002 
1003 		if (newMSR & UART_MSR_DDSR)
1004 			port_priv->icount.dsr++;
1005 
1006 		if (newMSR & UART_MSR_DDCD)
1007 			port_priv->icount.dcd++;
1008 
1009 		if (newMSR & UART_MSR_TERI)
1010 			port_priv->icount.rng++;
1011 
1012 		wake_up_interruptible(&port_priv->delta_msr_wait);
1013 	}
1014 }
1015 
1016 static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch)
1017 {
1018 	struct qt2_port_private *port_priv;
1019 	struct async_icount *icount;
1020 	unsigned long flags;
1021 	u8 newLSR = (u8) *ch;
1022 
1023 	port_priv = usb_get_serial_port_data(port);
1024 
1025 	if (newLSR & UART_LSR_BI)
1026 		newLSR &= (u8) (UART_LSR_OE | UART_LSR_BI);
1027 
1028 	spin_lock_irqsave(&port_priv->lock, flags);
1029 	port_priv->shadowLSR = newLSR;
1030 	spin_unlock_irqrestore(&port_priv->lock, flags);
1031 
1032 	icount = &port_priv->icount;
1033 
1034 	if (newLSR & UART_LSR_BRK_ERROR_BITS) {
1035 
1036 		if (newLSR & UART_LSR_BI)
1037 			icount->brk++;
1038 
1039 		if (newLSR & UART_LSR_OE)
1040 			icount->overrun++;
1041 
1042 		if (newLSR & UART_LSR_PE)
1043 			icount->parity++;
1044 
1045 		if (newLSR & UART_LSR_FE)
1046 			icount->frame++;
1047 	}
1048 
1049 }
1050 
1051 static int qt2_write_room(struct tty_struct *tty)
1052 {
1053 	struct usb_serial_port *port = tty->driver_data;
1054 	struct qt2_port_private *port_priv;
1055 	unsigned long flags = 0;
1056 	int r;
1057 
1058 	port_priv = usb_get_serial_port_data(port);
1059 
1060 	spin_lock_irqsave(&port_priv->urb_lock, flags);
1061 
1062 	if (port_priv->urb_in_use)
1063 		r = 0;
1064 	else
1065 		r = QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE;
1066 
1067 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
1068 
1069 	return r;
1070 }
1071 
1072 static int qt2_write(struct tty_struct *tty,
1073 		     struct usb_serial_port *port,
1074 		     const unsigned char *buf, int count)
1075 {
1076 	struct qt2_port_private *port_priv;
1077 	struct urb *write_urb;
1078 	unsigned char *data;
1079 	unsigned long flags;
1080 	int status;
1081 	int bytes_out = 0;
1082 
1083 	port_priv = usb_get_serial_port_data(port);
1084 
1085 	if (port_priv->write_urb == NULL) {
1086 		dev_err(&port->dev, "%s - no output urb\n", __func__);
1087 		return 0;
1088 	}
1089 	write_urb = port_priv->write_urb;
1090 
1091 	count = min(count, QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE);
1092 
1093 	data = write_urb->transfer_buffer;
1094 	spin_lock_irqsave(&port_priv->urb_lock, flags);
1095 	if (port_priv->urb_in_use == true) {
1096 		printk(KERN_INFO "qt2_write - urb is in use\n");
1097 		goto write_out;
1098 	}
1099 
1100 	*data++ = QT2_CONTROL_BYTE;
1101 	*data++ = QT2_CONTROL_BYTE;
1102 	*data++ = port_priv->device_port;
1103 	put_unaligned_le16(count, data);
1104 	data += 2;
1105 	memcpy(data, buf, count);
1106 
1107 	write_urb->transfer_buffer_length = count + QT2_WRITE_CONTROL_SIZE;
1108 
1109 	status = usb_submit_urb(write_urb, GFP_ATOMIC);
1110 	if (status == 0) {
1111 		port_priv->urb_in_use = true;
1112 		bytes_out += count;
1113 	}
1114 
1115 write_out:
1116 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
1117 	return bytes_out;
1118 }
1119 
1120 
1121 static struct usb_serial_driver qt2_device = {
1122 	.driver = {
1123 		.owner = THIS_MODULE,
1124 		.name = "quatech-serial",
1125 	},
1126 	.description	     = DRIVER_DESC,
1127 	.id_table	     = id_table,
1128 	.open		     = qt2_open,
1129 	.close		     = qt2_close,
1130 	.write               = qt2_write,
1131 	.write_room          = qt2_write_room,
1132 	.calc_num_ports      = qt2_calc_num_ports,
1133 	.attach              = qt2_attach,
1134 	.release             = qt2_release,
1135 	.disconnect          = qt2_disconnect,
1136 	.dtr_rts             = qt2_dtr_rts,
1137 	.break_ctl           = qt2_break_ctl,
1138 	.tiocmget            = qt2_tiocmget,
1139 	.tiocmset            = qt2_tiocmset,
1140 	.get_icount	     = qt2_get_icount,
1141 	.ioctl               = qt2_ioctl,
1142 	.set_termios         = qt2_set_termios,
1143 };
1144 
1145 static struct usb_serial_driver *const serial_drivers[] = {
1146 	&qt2_device, NULL
1147 };
1148 
1149 module_usb_serial_driver(serial_drivers, id_table);
1150 
1151 MODULE_DESCRIPTION(DRIVER_DESC);
1152 MODULE_LICENSE("GPL");
1153 
1154 module_param(debug, bool, S_IRUGO | S_IWUSR);
1155 MODULE_PARM_DESC(debug, "Debug enabled or not");
1156