xref: /openbmc/linux/drivers/usb/serial/quatech2.c (revision 05bcf503)
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 /* default urb timeout for usb operations */
31 #define QT2_USB_TIMEOUT USB_CTRL_SET_TIMEOUT
32 
33 #define QT_OPEN_CLOSE_CHANNEL       0xca
34 #define QT_SET_GET_DEVICE           0xc2
35 #define QT_SET_GET_REGISTER         0xc0
36 #define QT_GET_SET_PREBUF_TRIG_LVL  0xcc
37 #define QT_SET_ATF                  0xcd
38 #define QT_TRANSFER_IN              0xc0
39 #define QT_HW_FLOW_CONTROL_MASK     0xc5
40 #define QT_SW_FLOW_CONTROL_MASK     0xc6
41 #define QT2_BREAK_CONTROL	    0xc8
42 #define QT2_GET_SET_UART            0xc1
43 #define QT2_FLUSH_DEVICE	    0xc4
44 #define QT2_GET_SET_QMCR            0xe1
45 #define QT2_QMCR_RS232              0x40
46 #define QT2_QMCR_RS422              0x10
47 
48 #define  SERIAL_CRTSCTS ((UART_MCR_RTS << 8) | UART_MSR_CTS)
49 
50 #define  SERIAL_EVEN_PARITY         (UART_LCR_PARITY | UART_LCR_EPAR)
51 
52 /* status bytes for the device */
53 #define QT2_CONTROL_BYTE    0x1b
54 #define QT2_LINE_STATUS     0x00  /* following 1 byte is line status */
55 #define QT2_MODEM_STATUS    0x01  /* following 1 byte is modem status */
56 #define QT2_XMIT_HOLD       0x02  /* following 2 bytes are ?? */
57 #define QT2_CHANGE_PORT     0x03  /* following 1 byte is port to change to */
58 #define QT2_REC_FLUSH       0x04  /* no following info */
59 #define QT2_XMIT_FLUSH      0x05  /* no following info */
60 #define QT2_CONTROL_ESCAPE  0xff  /* pass through previous 2 control bytes */
61 
62 #define  MAX_BAUD_RATE              921600
63 #define  DEFAULT_BAUD_RATE          9600
64 
65 #define QT2_WRITE_BUFFER_SIZE   512  /* size of write buffer */
66 #define QT2_WRITE_CONTROL_SIZE  5    /* control bytes used for a write */
67 
68 /* Version Information */
69 #define DRIVER_VERSION "v0.1"
70 #define DRIVER_DESC "Quatech 2nd gen USB to Serial Driver"
71 
72 #define	USB_VENDOR_ID_QUATECH	0x061d
73 #define QUATECH_SSU2_100	0xC120	/* RS232 single port */
74 #define QUATECH_DSU2_100	0xC140	/* RS232 dual port */
75 #define QUATECH_DSU2_400	0xC150	/* RS232/422/485 dual port */
76 #define QUATECH_QSU2_100	0xC160	/* RS232 four port */
77 #define QUATECH_QSU2_400	0xC170	/* RS232/422/485 four port */
78 #define QUATECH_ESU2_100	0xC1A0	/* RS232 eight port */
79 #define QUATECH_ESU2_400	0xC180	/* RS232/422/485 eight port */
80 
81 struct qt2_device_detail {
82 	int product_id;
83 	int num_ports;
84 };
85 
86 #define QT_DETAILS(prod, ports)	\
87 	.product_id = (prod),   \
88 	.num_ports = (ports)
89 
90 static const struct qt2_device_detail qt2_device_details[] = {
91 	{QT_DETAILS(QUATECH_SSU2_100, 1)},
92 	{QT_DETAILS(QUATECH_DSU2_400, 2)},
93 	{QT_DETAILS(QUATECH_DSU2_100, 2)},
94 	{QT_DETAILS(QUATECH_QSU2_400, 4)},
95 	{QT_DETAILS(QUATECH_QSU2_100, 4)},
96 	{QT_DETAILS(QUATECH_ESU2_400, 8)},
97 	{QT_DETAILS(QUATECH_ESU2_100, 8)},
98 	{QT_DETAILS(0, 0)}	/* Terminating entry */
99 };
100 
101 static const struct usb_device_id id_table[] = {
102 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_SSU2_100)},
103 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_DSU2_100)},
104 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_DSU2_400)},
105 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_QSU2_100)},
106 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_QSU2_400)},
107 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_ESU2_100)},
108 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_ESU2_400)},
109 	{}			/* Terminating entry */
110 };
111 MODULE_DEVICE_TABLE(usb, id_table);
112 
113 struct qt2_serial_private {
114 	unsigned char current_port;  /* current port for incoming data */
115 
116 	struct urb	*read_urb;   /* shared among all ports */
117 	char		read_buffer[512];
118 };
119 
120 struct qt2_port_private {
121 	bool is_open;
122 	u8   device_port;
123 
124 	spinlock_t urb_lock;
125 	bool       urb_in_use;
126 	struct urb *write_urb;
127 	char       write_buffer[QT2_WRITE_BUFFER_SIZE];
128 
129 	spinlock_t  lock;
130 	u8          shadowLSR;
131 	u8          shadowMSR;
132 
133 	wait_queue_head_t   delta_msr_wait; /* Used for TIOCMIWAIT */
134 	struct async_icount icount;
135 
136 	struct usb_serial_port *port;
137 };
138 
139 static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch);
140 static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch);
141 static void qt2_write_bulk_callback(struct urb *urb);
142 static void qt2_read_bulk_callback(struct urb *urb);
143 
144 static void qt2_release(struct usb_serial *serial)
145 {
146 	struct qt2_serial_private *serial_priv;
147 
148 	serial_priv = usb_get_serial_data(serial);
149 
150 	usb_free_urb(serial_priv->read_urb);
151 	kfree(serial_priv);
152 }
153 
154 static inline int calc_baud_divisor(int baudrate)
155 {
156 	int divisor, rem;
157 
158 	divisor = MAX_BAUD_RATE / baudrate;
159 	rem = MAX_BAUD_RATE % baudrate;
160 	/* Round to nearest divisor */
161 	if (((rem * 2) >= baudrate) && (baudrate != 110))
162 		divisor++;
163 
164 	return divisor;
165 }
166 
167 static inline int qt2_set_port_config(struct usb_device *dev,
168 				      unsigned char port_number,
169 				      u16 baudrate, u16 lcr)
170 {
171 	int divisor = calc_baud_divisor(baudrate);
172 	u16 index = ((u16) (lcr << 8) | (u16) (port_number));
173 
174 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
175 			       QT2_GET_SET_UART, 0x40,
176 			       divisor, index, NULL, 0, QT2_USB_TIMEOUT);
177 }
178 
179 static inline int qt2_control_msg(struct usb_device *dev,
180 				  u8 request, u16 data, u16 index)
181 {
182 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
183 			       request, 0x40, data, index,
184 			       NULL, 0, QT2_USB_TIMEOUT);
185 }
186 
187 static inline int qt2_setdevice(struct usb_device *dev, u8 *data)
188 {
189 	u16 x = ((u16) (data[1] << 8) | (u16) (data[0]));
190 
191 	return qt2_control_msg(dev, QT_SET_GET_DEVICE, x, 0);
192 }
193 
194 
195 static inline int qt2_getdevice(struct usb_device *dev, u8 *data)
196 {
197 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
198 			       QT_SET_GET_DEVICE, 0xc0, 0, 0,
199 			       data, 3, QT2_USB_TIMEOUT);
200 }
201 
202 static inline int qt2_getregister(struct usb_device *dev,
203 				  u8 uart,
204 				  u8 reg,
205 				  u8 *data)
206 {
207 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
208 			       QT_SET_GET_REGISTER, 0xc0, reg,
209 			       uart, data, sizeof(*data), QT2_USB_TIMEOUT);
210 
211 }
212 
213 static inline int qt2_setregister(struct usb_device *dev,
214 				  u8 uart, u8 reg, u16 data)
215 {
216 	u16 value = (data << 8) | reg;
217 
218 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
219 			       QT_SET_GET_REGISTER, 0x40, value, uart,
220 			       NULL, 0, QT2_USB_TIMEOUT);
221 }
222 
223 static inline int update_mctrl(struct qt2_port_private *port_priv,
224 			       unsigned int set, unsigned int clear)
225 {
226 	struct usb_serial_port *port = port_priv->port;
227 	struct usb_device *dev = port->serial->dev;
228 	unsigned urb_value;
229 	int status;
230 
231 	if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) {
232 		dev_dbg(&port->dev,
233 			"update_mctrl - DTR|RTS not being set|cleared\n");
234 		return 0;	/* no change */
235 	}
236 
237 	clear &= ~set;	/* 'set' takes precedence over 'clear' */
238 	urb_value = 0;
239 	if (set & TIOCM_DTR)
240 		urb_value |= UART_MCR_DTR;
241 	if (set & TIOCM_RTS)
242 		urb_value |= UART_MCR_RTS;
243 
244 	status = qt2_setregister(dev, port_priv->device_port, UART_MCR,
245 				 urb_value);
246 	if (status < 0)
247 		dev_err(&port->dev,
248 			"update_mctrl - Error from MODEM_CTRL urb: %i\n",
249 			status);
250 	return status;
251 }
252 
253 static int qt2_calc_num_ports(struct usb_serial *serial)
254 {
255 	struct qt2_device_detail d;
256 	int i;
257 
258 	for (i = 0; d = qt2_device_details[i], d.product_id != 0; i++) {
259 		if (d.product_id == le16_to_cpu(serial->dev->descriptor.idProduct))
260 			return d.num_ports;
261 	}
262 
263 	/* we didn't recognize the device */
264 	dev_err(&serial->dev->dev,
265 		 "don't know the number of ports, assuming 1\n");
266 
267 	return 1;
268 }
269 
270 static void qt2_set_termios(struct tty_struct *tty,
271 			    struct usb_serial_port *port,
272 			    struct ktermios *old_termios)
273 {
274 	struct usb_device *dev = port->serial->dev;
275 	struct qt2_port_private *port_priv;
276 	struct ktermios *termios = &tty->termios;
277 	u16 baud;
278 	unsigned int cflag = termios->c_cflag;
279 	u16 new_lcr = 0;
280 	int status;
281 
282 	port_priv = usb_get_serial_port_data(port);
283 
284 	if (cflag & PARENB) {
285 		if (cflag & PARODD)
286 			new_lcr |= UART_LCR_PARITY;
287 		else
288 			new_lcr |= SERIAL_EVEN_PARITY;
289 	}
290 
291 	switch (cflag & CSIZE) {
292 	case CS5:
293 		new_lcr |= UART_LCR_WLEN5;
294 		break;
295 	case CS6:
296 		new_lcr |= UART_LCR_WLEN6;
297 		break;
298 	case CS7:
299 		new_lcr |= UART_LCR_WLEN7;
300 		break;
301 	default:
302 	case CS8:
303 		new_lcr |= UART_LCR_WLEN8;
304 		break;
305 	}
306 
307 	baud = tty_get_baud_rate(tty);
308 	if (!baud)
309 		baud = 9600;
310 
311 	status = qt2_set_port_config(dev, port_priv->device_port, baud,
312 				     new_lcr);
313 	if (status < 0)
314 		dev_err(&port->dev, "%s - qt2_set_port_config failed: %i\n",
315 			__func__, status);
316 
317 	if (cflag & CRTSCTS)
318 		status = qt2_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
319 					 SERIAL_CRTSCTS,
320 					 port_priv->device_port);
321 	else
322 		status = qt2_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
323 					 0, port_priv->device_port);
324 	if (status < 0)
325 		dev_err(&port->dev, "%s - set HW flow control failed: %i\n",
326 			__func__, status);
327 
328 	if (I_IXOFF(tty) || I_IXON(tty)) {
329 		u16 x = ((u16) (START_CHAR(tty) << 8) | (u16) (STOP_CHAR(tty)));
330 
331 		status = qt2_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
332 					 x, port_priv->device_port);
333 	} else
334 		status = qt2_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
335 					 0, port_priv->device_port);
336 
337 	if (status < 0)
338 		dev_err(&port->dev, "%s - set SW flow control failed: %i\n",
339 			__func__, status);
340 
341 }
342 
343 static int qt2_open(struct tty_struct *tty, struct usb_serial_port *port)
344 {
345 	struct usb_serial *serial;
346 	struct qt2_port_private *port_priv;
347 	u8 *data;
348 	u16 device_port;
349 	int status;
350 	unsigned long flags;
351 
352 	device_port = (u16) (port->number - port->serial->minor);
353 
354 	serial = port->serial;
355 
356 	port_priv = usb_get_serial_port_data(port);
357 
358 	/* set the port to RS232 mode */
359 	status = qt2_control_msg(serial->dev, QT2_GET_SET_QMCR,
360 				 QT2_QMCR_RS232, device_port);
361 	if (status < 0) {
362 		dev_err(&port->dev,
363 			"%s failed to set RS232 mode for port %i error %i\n",
364 			__func__, device_port, status);
365 		return status;
366 	}
367 
368 	data = kzalloc(2, GFP_KERNEL);
369 	if (!data)
370 		return -ENOMEM;
371 
372 	/* open the port */
373 	status = usb_control_msg(serial->dev,
374 				 usb_rcvctrlpipe(serial->dev, 0),
375 				 QT_OPEN_CLOSE_CHANNEL,
376 				 0xc0, 0,
377 				 device_port, data, 2, QT2_USB_TIMEOUT);
378 
379 	if (status < 0) {
380 		dev_err(&port->dev, "%s - open port failed %i", __func__,
381 			status);
382 		kfree(data);
383 		return status;
384 	}
385 
386 	spin_lock_irqsave(&port_priv->lock, flags);
387 	port_priv->shadowLSR = data[0];
388 	port_priv->shadowMSR = data[1];
389 	spin_unlock_irqrestore(&port_priv->lock, flags);
390 
391 	kfree(data);
392 
393 	/* set to default speed and 8bit word size */
394 	status = qt2_set_port_config(serial->dev, device_port,
395 				     DEFAULT_BAUD_RATE, UART_LCR_WLEN8);
396 	if (status < 0) {
397 		dev_err(&port->dev,
398 			"%s - initial setup failed for port %i (%i)\n",
399 			__func__, port->number, device_port);
400 		return status;
401 	}
402 
403 	port_priv->is_open = true;
404 	port_priv->device_port = (u8) device_port;
405 
406 	if (tty)
407 		qt2_set_termios(tty, port, &tty->termios);
408 
409 	return 0;
410 
411 }
412 
413 static void qt2_close(struct usb_serial_port *port)
414 {
415 	struct usb_serial *serial;
416 	struct qt2_port_private *port_priv;
417 	unsigned long flags;
418 	int i;
419 
420 	serial = port->serial;
421 	port_priv = usb_get_serial_port_data(port);
422 
423 	port_priv->is_open = false;
424 
425 	spin_lock_irqsave(&port_priv->urb_lock, flags);
426 	usb_kill_urb(port_priv->write_urb);
427 	port_priv->urb_in_use = false;
428 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
429 
430 	mutex_lock(&port->serial->disc_mutex);
431 	if (port->serial->disconnected) {
432 		mutex_unlock(&port->serial->disc_mutex);
433 		return;
434 	}
435 
436 	/* flush the port transmit buffer */
437 	i = usb_control_msg(serial->dev,
438 			    usb_rcvctrlpipe(serial->dev, 0),
439 			    QT2_FLUSH_DEVICE, 0x40, 1,
440 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
441 
442 	if (i < 0)
443 		dev_err(&port->dev, "%s - transmit buffer flush failed: %i\n",
444 			__func__, i);
445 
446 	/* flush the port receive buffer */
447 	i = usb_control_msg(serial->dev,
448 			    usb_rcvctrlpipe(serial->dev, 0),
449 			    QT2_FLUSH_DEVICE, 0x40, 0,
450 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
451 
452 	if (i < 0)
453 		dev_err(&port->dev, "%s - receive buffer flush failed: %i\n",
454 			__func__, i);
455 
456 	/* close the port */
457 	i = usb_control_msg(serial->dev,
458 			    usb_sndctrlpipe(serial->dev, 0),
459 			    QT_OPEN_CLOSE_CHANNEL,
460 			    0x40, 0,
461 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
462 
463 	if (i < 0)
464 		dev_err(&port->dev, "%s - close port failed %i\n",
465 			__func__, i);
466 
467 	mutex_unlock(&port->serial->disc_mutex);
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 
474 	usb_kill_urb(serial_priv->read_urb);
475 }
476 
477 static int get_serial_info(struct usb_serial_port *port,
478 			   struct serial_struct __user *retinfo)
479 {
480 	struct serial_struct tmp;
481 
482 	if (!retinfo)
483 		return -EFAULT;
484 
485 	memset(&tmp, 0, sizeof(tmp));
486 	tmp.line		= port->serial->minor;
487 	tmp.port		= 0;
488 	tmp.irq			= 0;
489 	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
490 	tmp.xmit_fifo_size	= port->bulk_out_size;
491 	tmp.baud_base		= 9600;
492 	tmp.close_delay		= 5*HZ;
493 	tmp.closing_wait	= 30*HZ;
494 
495 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
496 		return -EFAULT;
497 	return 0;
498 }
499 
500 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
501 {
502 	struct qt2_port_private *priv = usb_get_serial_port_data(port);
503 	struct async_icount prev, cur;
504 	unsigned long flags;
505 
506 	spin_lock_irqsave(&priv->lock, flags);
507 	prev = priv->icount;
508 	spin_unlock_irqrestore(&priv->lock, flags);
509 
510 	while (1) {
511 		wait_event_interruptible(priv->delta_msr_wait,
512 					 ((priv->icount.rng != prev.rng) ||
513 					  (priv->icount.dsr != prev.dsr) ||
514 					  (priv->icount.dcd != prev.dcd) ||
515 					  (priv->icount.cts != prev.cts)));
516 
517 		if (signal_pending(current))
518 			return -ERESTARTSYS;
519 
520 		spin_lock_irqsave(&priv->lock, flags);
521 		cur = priv->icount;
522 		spin_unlock_irqrestore(&priv->lock, flags);
523 
524 		if ((prev.rng == cur.rng) &&
525 		    (prev.dsr == cur.dsr) &&
526 		    (prev.dcd == cur.dcd) &&
527 		    (prev.cts == cur.cts))
528 			return -EIO;
529 
530 		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
531 		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
532 		    (arg & TIOCM_CD && (prev.dcd != cur.dcd)) ||
533 		    (arg & TIOCM_CTS && (prev.cts != cur.cts)))
534 			return 0;
535 	}
536 	return 0;
537 }
538 
539 static int qt2_get_icount(struct tty_struct *tty,
540 			  struct serial_icounter_struct *icount)
541 {
542 	struct usb_serial_port *port = tty->driver_data;
543 	struct qt2_port_private *priv = usb_get_serial_port_data(port);
544 	struct async_icount cnow = priv->icount;
545 
546 	icount->cts = cnow.cts;
547 	icount->dsr = cnow.dsr;
548 	icount->rng = cnow.rng;
549 	icount->dcd = cnow.dcd;
550 	icount->rx = cnow.rx;
551 	icount->tx = cnow.tx;
552 	icount->frame = cnow.frame;
553 	icount->overrun = cnow.overrun;
554 	icount->parity = cnow.parity;
555 	icount->brk = cnow.brk;
556 	icount->buf_overrun = cnow.buf_overrun;
557 
558 	return 0;
559 }
560 
561 static int qt2_ioctl(struct tty_struct *tty,
562 		     unsigned int cmd, unsigned long arg)
563 {
564 	struct usb_serial_port *port = tty->driver_data;
565 
566 	switch (cmd) {
567 	case TIOCGSERIAL:
568 		return get_serial_info(port,
569 				       (struct serial_struct __user *)arg);
570 
571 	case TIOCMIWAIT:
572 		return wait_modem_info(port, arg);
573 
574 	default:
575 		break;
576 	}
577 
578 	return -ENOIOCTLCMD;
579 }
580 
581 static void qt2_process_status(struct usb_serial_port *port, unsigned char *ch)
582 {
583 	switch (*ch) {
584 	case QT2_LINE_STATUS:
585 		qt2_update_lsr(port, ch + 1);
586 		break;
587 	case QT2_MODEM_STATUS:
588 		qt2_update_msr(port, ch + 1);
589 		break;
590 	}
591 }
592 
593 /* not needed, kept to document functionality */
594 static void qt2_process_xmit_empty(struct usb_serial_port *port,
595 				   unsigned char *ch)
596 {
597 	int bytes_written;
598 
599 	bytes_written = (int)(*ch) + (int)(*(ch + 1) << 4);
600 }
601 
602 /* not needed, kept to document functionality */
603 static void qt2_process_flush(struct usb_serial_port *port, unsigned char *ch)
604 {
605 	return;
606 }
607 
608 void qt2_process_read_urb(struct urb *urb)
609 {
610 	struct usb_serial *serial;
611 	struct qt2_serial_private *serial_priv;
612 	struct usb_serial_port *port;
613 	struct qt2_port_private *port_priv;
614 	struct tty_struct *tty;
615 	bool escapeflag;
616 	unsigned char *ch;
617 	int i;
618 	unsigned char newport;
619 	int len = urb->actual_length;
620 
621 	if (!len)
622 		return;
623 
624 	ch = urb->transfer_buffer;
625 	tty = NULL;
626 	serial = urb->context;
627 	serial_priv = usb_get_serial_data(serial);
628 	port = serial->port[serial_priv->current_port];
629 	port_priv = usb_get_serial_port_data(port);
630 
631 	if (port_priv->is_open)
632 		tty = tty_port_tty_get(&port->port);
633 
634 	for (i = 0; i < urb->actual_length; i++) {
635 		ch = (unsigned char *)urb->transfer_buffer + i;
636 		if ((i <= (len - 3)) &&
637 		    (*ch == QT2_CONTROL_BYTE) &&
638 		    (*(ch + 1) == QT2_CONTROL_BYTE)) {
639 			escapeflag = false;
640 			switch (*(ch + 2)) {
641 			case QT2_LINE_STATUS:
642 			case QT2_MODEM_STATUS:
643 				if (i > (len - 4)) {
644 					dev_warn(&port->dev,
645 						 "%s - status message too short\n",
646 						__func__);
647 					break;
648 				}
649 				qt2_process_status(port, ch + 2);
650 				i += 3;
651 				escapeflag = true;
652 				break;
653 			case QT2_XMIT_HOLD:
654 				if (i > (len - 5)) {
655 					dev_warn(&port->dev,
656 						 "%s - xmit_empty message too short\n",
657 						 __func__);
658 					break;
659 				}
660 				qt2_process_xmit_empty(port, ch + 3);
661 				i += 4;
662 				escapeflag = true;
663 				break;
664 			case QT2_CHANGE_PORT:
665 				if (i > (len - 4)) {
666 					dev_warn(&port->dev,
667 						 "%s - change_port message too short\n",
668 						 __func__);
669 					break;
670 				}
671 				if (tty) {
672 					tty_flip_buffer_push(tty);
673 					tty_kref_put(tty);
674 				}
675 
676 				newport = *(ch + 3);
677 
678 				if (newport > serial->num_ports) {
679 					dev_err(&port->dev,
680 						"%s - port change to invalid port: %i\n",
681 						__func__, newport);
682 					break;
683 				}
684 
685 				serial_priv->current_port = newport;
686 				port = serial->port[serial_priv->current_port];
687 				port_priv = usb_get_serial_port_data(port);
688 				if (port_priv->is_open)
689 					tty = tty_port_tty_get(&port->port);
690 				else
691 					tty = NULL;
692 				i += 3;
693 				escapeflag = true;
694 				break;
695 			case QT2_REC_FLUSH:
696 			case QT2_XMIT_FLUSH:
697 				qt2_process_flush(port, ch + 2);
698 				i += 2;
699 				escapeflag = true;
700 				break;
701 			case QT2_CONTROL_ESCAPE:
702 				tty_buffer_request_room(tty, 2);
703 				tty_insert_flip_string(tty, ch, 2);
704 				i += 2;
705 				escapeflag = true;
706 				break;
707 			default:
708 				dev_warn(&port->dev,
709 					 "%s - unsupported command %i\n",
710 					 __func__, *(ch + 2));
711 				break;
712 			}
713 			if (escapeflag)
714 				continue;
715 		}
716 
717 		if (tty) {
718 			tty_buffer_request_room(tty, 1);
719 			tty_insert_flip_string(tty, ch, 1);
720 		}
721 	}
722 
723 	if (tty) {
724 		tty_flip_buffer_push(tty);
725 		tty_kref_put(tty);
726 	}
727 }
728 
729 static void qt2_write_bulk_callback(struct urb *urb)
730 {
731 	struct usb_serial_port *port;
732 	struct qt2_port_private *port_priv;
733 
734 	port = urb->context;
735 	port_priv = usb_get_serial_port_data(port);
736 
737 	spin_lock(&port_priv->urb_lock);
738 
739 	port_priv->urb_in_use = false;
740 	usb_serial_port_softint(port);
741 
742 	spin_unlock(&port_priv->urb_lock);
743 
744 }
745 
746 static void qt2_read_bulk_callback(struct urb *urb)
747 {
748 	struct usb_serial *serial = urb->context;
749 	int status;
750 
751 	if (urb->status) {
752 		dev_warn(&serial->dev->dev,
753 			 "%s - non-zero urb status: %i\n", __func__,
754 			 urb->status);
755 		return;
756 	}
757 
758 	qt2_process_read_urb(urb);
759 
760 	status = usb_submit_urb(urb, GFP_ATOMIC);
761 	if (status != 0)
762 		dev_err(&serial->dev->dev,
763 			"%s - resubmit read urb failed: %i\n",
764 			__func__, status);
765 }
766 
767 static int qt2_setup_urbs(struct usb_serial *serial)
768 {
769 	struct usb_serial_port *port0;
770 	struct qt2_serial_private *serial_priv;
771 	int status;
772 
773 	port0 = serial->port[0];
774 
775 	serial_priv = usb_get_serial_data(serial);
776 	serial_priv->read_urb = usb_alloc_urb(0, GFP_KERNEL);
777 	if (!serial_priv->read_urb) {
778 		dev_err(&serial->dev->dev, "No free urbs available\n");
779 		return -ENOMEM;
780 	}
781 
782 	usb_fill_bulk_urb(serial_priv->read_urb, serial->dev,
783 			  usb_rcvbulkpipe(serial->dev,
784 					  port0->bulk_in_endpointAddress),
785 			  serial_priv->read_buffer,
786 			  sizeof(serial_priv->read_buffer),
787 			  qt2_read_bulk_callback, serial);
788 
789 	status = usb_submit_urb(serial_priv->read_urb, GFP_KERNEL);
790 	if (status != 0) {
791 		dev_err(&serial->dev->dev,
792 			"%s - submit read urb failed %i\n", __func__, status);
793 		usb_free_urb(serial_priv->read_urb);
794 		return status;
795 	}
796 
797 	return 0;
798 }
799 
800 static int qt2_attach(struct usb_serial *serial)
801 {
802 	struct qt2_serial_private *serial_priv;
803 	int status;
804 
805 	/* power on unit */
806 	status = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
807 				 0xc2, 0x40, 0x8000, 0, NULL, 0,
808 				 QT2_USB_TIMEOUT);
809 	if (status < 0) {
810 		dev_err(&serial->dev->dev,
811 			"%s - failed to power on unit: %i\n", __func__, status);
812 		return status;
813 	}
814 
815 	serial_priv = kzalloc(sizeof(*serial_priv), GFP_KERNEL);
816 	if (!serial_priv) {
817 		dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
818 		return -ENOMEM;
819 	}
820 
821 	usb_set_serial_data(serial, serial_priv);
822 
823 	status = qt2_setup_urbs(serial);
824 	if (status != 0)
825 		goto attach_failed;
826 
827 	return 0;
828 
829 attach_failed:
830 	kfree(serial_priv);
831 	return status;
832 }
833 
834 static int qt2_port_probe(struct usb_serial_port *port)
835 {
836 	struct usb_serial *serial = port->serial;
837 	struct qt2_port_private *port_priv;
838 	u8 bEndpointAddress;
839 
840 	port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
841 	if (!port_priv)
842 		return -ENOMEM;
843 
844 	spin_lock_init(&port_priv->lock);
845 	spin_lock_init(&port_priv->urb_lock);
846 	init_waitqueue_head(&port_priv->delta_msr_wait);
847 	port_priv->port = port;
848 
849 	port_priv->write_urb = usb_alloc_urb(0, GFP_KERNEL);
850 	if (!port_priv->write_urb) {
851 		kfree(port_priv);
852 		return -ENOMEM;
853 	}
854 	bEndpointAddress = serial->port[0]->bulk_out_endpointAddress;
855 	usb_fill_bulk_urb(port_priv->write_urb, serial->dev,
856 				usb_sndbulkpipe(serial->dev, bEndpointAddress),
857 				port_priv->write_buffer,
858 				sizeof(port_priv->write_buffer),
859 				qt2_write_bulk_callback, port);
860 
861 	usb_set_serial_port_data(port, port_priv);
862 
863 	return 0;
864 }
865 
866 static int qt2_port_remove(struct usb_serial_port *port)
867 {
868 	struct qt2_port_private *port_priv;
869 
870 	port_priv = usb_get_serial_port_data(port);
871 	usb_free_urb(port_priv->write_urb);
872 	kfree(port_priv);
873 
874 	return 0;
875 }
876 
877 static int qt2_tiocmget(struct tty_struct *tty)
878 {
879 	struct usb_serial_port *port = tty->driver_data;
880 	struct usb_device *dev = port->serial->dev;
881 	struct qt2_port_private *port_priv = usb_get_serial_port_data(port);
882 	u8 *d;
883 	int r;
884 
885 	d = kzalloc(2, GFP_KERNEL);
886 	if (!d)
887 		return -ENOMEM;
888 
889 	r = qt2_getregister(dev, port_priv->device_port, UART_MCR, d);
890 	if (r < 0)
891 		goto mget_out;
892 
893 	r = qt2_getregister(dev, port_priv->device_port, UART_MSR, d + 1);
894 	if (r < 0)
895 		goto mget_out;
896 
897 	r = (d[0] & UART_MCR_DTR ? TIOCM_DTR : 0) |
898 	    (d[0] & UART_MCR_RTS ? TIOCM_RTS : 0) |
899 	    (d[1] & UART_MSR_CTS ? TIOCM_CTS : 0) |
900 	    (d[1] & UART_MSR_DCD ? TIOCM_CAR : 0) |
901 	    (d[1] & UART_MSR_RI ? TIOCM_RI : 0) |
902 	    (d[1] & UART_MSR_DSR ? TIOCM_DSR : 0);
903 
904 mget_out:
905 	kfree(d);
906 	return r;
907 }
908 
909 static int qt2_tiocmset(struct tty_struct *tty,
910 			unsigned int set, unsigned int clear)
911 {
912 	struct qt2_port_private *port_priv;
913 
914 	port_priv = usb_get_serial_port_data(tty->driver_data);
915 	return update_mctrl(port_priv, set, clear);
916 }
917 
918 static void qt2_break_ctl(struct tty_struct *tty, int break_state)
919 {
920 	struct usb_serial_port *port = tty->driver_data;
921 	struct qt2_port_private *port_priv;
922 	int status;
923 	u16 val;
924 
925 	port_priv = usb_get_serial_port_data(port);
926 
927 	if (!port_priv->is_open) {
928 		dev_err(&port->dev,
929 			"%s - port is not open\n", __func__);
930 		return;
931 	}
932 
933 	val = (break_state == -1) ? 1 : 0;
934 
935 	status = qt2_control_msg(port->serial->dev, QT2_BREAK_CONTROL,
936 				 val, port_priv->device_port);
937 	if (status < 0)
938 		dev_warn(&port->dev,
939 			 "%s - failed to send control message: %i\n", __func__,
940 			 status);
941 }
942 
943 
944 
945 static void qt2_dtr_rts(struct usb_serial_port *port, int on)
946 {
947 	struct usb_device *dev = port->serial->dev;
948 	struct qt2_port_private *port_priv = usb_get_serial_port_data(port);
949 
950 	mutex_lock(&port->serial->disc_mutex);
951 	if (!port->serial->disconnected) {
952 		/* Disable flow control */
953 		if (!on && qt2_setregister(dev, port_priv->device_port,
954 					   UART_MCR, 0) < 0)
955 			dev_warn(&port->dev, "error from flowcontrol urb\n");
956 		/* drop RTS and DTR */
957 		if (on)
958 			update_mctrl(port_priv, TIOCM_DTR | TIOCM_RTS, 0);
959 		else
960 			update_mctrl(port_priv, 0, TIOCM_DTR | TIOCM_RTS);
961 	}
962 	mutex_unlock(&port->serial->disc_mutex);
963 }
964 
965 static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch)
966 {
967 	struct qt2_port_private *port_priv;
968 	u8 newMSR = (u8) *ch;
969 	unsigned long flags;
970 
971 	port_priv = usb_get_serial_port_data(port);
972 
973 	spin_lock_irqsave(&port_priv->lock, flags);
974 	port_priv->shadowMSR = newMSR;
975 	spin_unlock_irqrestore(&port_priv->lock, flags);
976 
977 	if (newMSR & UART_MSR_ANY_DELTA) {
978 		/* update input line counters */
979 		if (newMSR & UART_MSR_DCTS)
980 			port_priv->icount.cts++;
981 
982 		if (newMSR & UART_MSR_DDSR)
983 			port_priv->icount.dsr++;
984 
985 		if (newMSR & UART_MSR_DDCD)
986 			port_priv->icount.dcd++;
987 
988 		if (newMSR & UART_MSR_TERI)
989 			port_priv->icount.rng++;
990 
991 		wake_up_interruptible(&port_priv->delta_msr_wait);
992 	}
993 }
994 
995 static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch)
996 {
997 	struct qt2_port_private *port_priv;
998 	struct async_icount *icount;
999 	unsigned long flags;
1000 	u8 newLSR = (u8) *ch;
1001 
1002 	port_priv = usb_get_serial_port_data(port);
1003 
1004 	if (newLSR & UART_LSR_BI)
1005 		newLSR &= (u8) (UART_LSR_OE | UART_LSR_BI);
1006 
1007 	spin_lock_irqsave(&port_priv->lock, flags);
1008 	port_priv->shadowLSR = newLSR;
1009 	spin_unlock_irqrestore(&port_priv->lock, flags);
1010 
1011 	icount = &port_priv->icount;
1012 
1013 	if (newLSR & UART_LSR_BRK_ERROR_BITS) {
1014 
1015 		if (newLSR & UART_LSR_BI)
1016 			icount->brk++;
1017 
1018 		if (newLSR & UART_LSR_OE)
1019 			icount->overrun++;
1020 
1021 		if (newLSR & UART_LSR_PE)
1022 			icount->parity++;
1023 
1024 		if (newLSR & UART_LSR_FE)
1025 			icount->frame++;
1026 	}
1027 
1028 }
1029 
1030 static int qt2_write_room(struct tty_struct *tty)
1031 {
1032 	struct usb_serial_port *port = tty->driver_data;
1033 	struct qt2_port_private *port_priv;
1034 	unsigned long flags = 0;
1035 	int r;
1036 
1037 	port_priv = usb_get_serial_port_data(port);
1038 
1039 	spin_lock_irqsave(&port_priv->urb_lock, flags);
1040 
1041 	if (port_priv->urb_in_use)
1042 		r = 0;
1043 	else
1044 		r = QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE;
1045 
1046 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
1047 
1048 	return r;
1049 }
1050 
1051 static int qt2_write(struct tty_struct *tty,
1052 		     struct usb_serial_port *port,
1053 		     const unsigned char *buf, int count)
1054 {
1055 	struct qt2_port_private *port_priv;
1056 	struct urb *write_urb;
1057 	unsigned char *data;
1058 	unsigned long flags;
1059 	int status;
1060 	int bytes_out = 0;
1061 
1062 	port_priv = usb_get_serial_port_data(port);
1063 
1064 	if (port_priv->write_urb == NULL) {
1065 		dev_err(&port->dev, "%s - no output urb\n", __func__);
1066 		return 0;
1067 	}
1068 	write_urb = port_priv->write_urb;
1069 
1070 	count = min(count, QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE);
1071 
1072 	data = write_urb->transfer_buffer;
1073 	spin_lock_irqsave(&port_priv->urb_lock, flags);
1074 	if (port_priv->urb_in_use == true) {
1075 		dev_err(&port->dev, "qt2_write - urb is in use\n");
1076 		goto write_out;
1077 	}
1078 
1079 	*data++ = QT2_CONTROL_BYTE;
1080 	*data++ = QT2_CONTROL_BYTE;
1081 	*data++ = port_priv->device_port;
1082 	put_unaligned_le16(count, data);
1083 	data += 2;
1084 	memcpy(data, buf, count);
1085 
1086 	write_urb->transfer_buffer_length = count + QT2_WRITE_CONTROL_SIZE;
1087 
1088 	status = usb_submit_urb(write_urb, GFP_ATOMIC);
1089 	if (status == 0) {
1090 		port_priv->urb_in_use = true;
1091 		bytes_out += count;
1092 	}
1093 
1094 write_out:
1095 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
1096 	return bytes_out;
1097 }
1098 
1099 
1100 static struct usb_serial_driver qt2_device = {
1101 	.driver = {
1102 		.owner = THIS_MODULE,
1103 		.name = "quatech-serial",
1104 	},
1105 	.description	     = DRIVER_DESC,
1106 	.id_table	     = id_table,
1107 	.open		     = qt2_open,
1108 	.close		     = qt2_close,
1109 	.write               = qt2_write,
1110 	.write_room          = qt2_write_room,
1111 	.calc_num_ports      = qt2_calc_num_ports,
1112 	.attach              = qt2_attach,
1113 	.release             = qt2_release,
1114 	.disconnect          = qt2_disconnect,
1115 	.port_probe          = qt2_port_probe,
1116 	.port_remove         = qt2_port_remove,
1117 	.dtr_rts             = qt2_dtr_rts,
1118 	.break_ctl           = qt2_break_ctl,
1119 	.tiocmget            = qt2_tiocmget,
1120 	.tiocmset            = qt2_tiocmset,
1121 	.get_icount	     = qt2_get_icount,
1122 	.ioctl               = qt2_ioctl,
1123 	.set_termios         = qt2_set_termios,
1124 };
1125 
1126 static struct usb_serial_driver *const serial_drivers[] = {
1127 	&qt2_device, NULL
1128 };
1129 
1130 module_usb_serial_driver(serial_drivers, id_table);
1131 
1132 MODULE_DESCRIPTION(DRIVER_DESC);
1133 MODULE_LICENSE("GPL");
1134