xref: /linux/drivers/usb/serial/quatech2.c (revision 08ec212c0f92cbf30e3ecc7349f18151714041d6)
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 	int i;
147 
148 	kfree(usb_get_serial_data(serial));
149 
150 	for (i = 0; i < serial->num_ports; i++)
151 		kfree(usb_get_serial_port_data(serial->port[i]));
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 	if (port_priv->write_urb->status == -EINPROGRESS)
427 		usb_kill_urb(port_priv->write_urb);
428 	port_priv->urb_in_use = false;
429 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
430 
431 	/* flush the port transmit buffer */
432 	i = usb_control_msg(serial->dev,
433 			    usb_rcvctrlpipe(serial->dev, 0),
434 			    QT2_FLUSH_DEVICE, 0x40, 1,
435 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
436 
437 	if (i < 0)
438 		dev_err(&port->dev, "%s - transmit buffer flush failed: %i\n",
439 			__func__, i);
440 
441 	/* flush the port receive buffer */
442 	i = usb_control_msg(serial->dev,
443 			    usb_rcvctrlpipe(serial->dev, 0),
444 			    QT2_FLUSH_DEVICE, 0x40, 0,
445 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
446 
447 	if (i < 0)
448 		dev_err(&port->dev, "%s - receive buffer flush failed: %i\n",
449 			__func__, i);
450 
451 	/* close the port */
452 	i = usb_control_msg(serial->dev,
453 			    usb_sndctrlpipe(serial->dev, 0),
454 			    QT_OPEN_CLOSE_CHANNEL,
455 			    0x40, 0,
456 			    port_priv->device_port, NULL, 0, QT2_USB_TIMEOUT);
457 
458 	if (i < 0)
459 		dev_err(&port->dev, "%s - close port failed %i\n",
460 			__func__, i);
461 
462 }
463 
464 static void qt2_disconnect(struct usb_serial *serial)
465 {
466 	struct qt2_serial_private *serial_priv = usb_get_serial_data(serial);
467 	struct qt2_port_private *port_priv;
468 	int i;
469 
470 	if (serial_priv->read_urb->status == -EINPROGRESS)
471 		usb_kill_urb(serial_priv->read_urb);
472 
473 	usb_free_urb(serial_priv->read_urb);
474 
475 	for (i = 0; i < serial->num_ports; i++) {
476 		port_priv = usb_get_serial_port_data(serial->port[i]);
477 
478 		if (port_priv->write_urb->status == -EINPROGRESS)
479 			usb_kill_urb(port_priv->write_urb);
480 		usb_free_urb(port_priv->write_urb);
481 	}
482 }
483 
484 static int get_serial_info(struct usb_serial_port *port,
485 			   struct serial_struct __user *retinfo)
486 {
487 	struct serial_struct tmp;
488 
489 	if (!retinfo)
490 		return -EFAULT;
491 
492 	memset(&tmp, 0, sizeof(tmp));
493 	tmp.line		= port->serial->minor;
494 	tmp.port		= 0;
495 	tmp.irq			= 0;
496 	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
497 	tmp.xmit_fifo_size	= port->bulk_out_size;
498 	tmp.baud_base		= 9600;
499 	tmp.close_delay		= 5*HZ;
500 	tmp.closing_wait	= 30*HZ;
501 
502 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
503 		return -EFAULT;
504 	return 0;
505 }
506 
507 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
508 {
509 	struct qt2_port_private *priv = usb_get_serial_port_data(port);
510 	struct async_icount prev, cur;
511 	unsigned long flags;
512 
513 	spin_lock_irqsave(&priv->lock, flags);
514 	prev = priv->icount;
515 	spin_unlock_irqrestore(&priv->lock, flags);
516 
517 	while (1) {
518 		wait_event_interruptible(priv->delta_msr_wait,
519 					 ((priv->icount.rng != prev.rng) ||
520 					  (priv->icount.dsr != prev.dsr) ||
521 					  (priv->icount.dcd != prev.dcd) ||
522 					  (priv->icount.cts != prev.cts)));
523 
524 		if (signal_pending(current))
525 			return -ERESTARTSYS;
526 
527 		spin_lock_irqsave(&priv->lock, flags);
528 		cur = priv->icount;
529 		spin_unlock_irqrestore(&priv->lock, flags);
530 
531 		if ((prev.rng == cur.rng) &&
532 		    (prev.dsr == cur.dsr) &&
533 		    (prev.dcd == cur.dcd) &&
534 		    (prev.cts == cur.cts))
535 			return -EIO;
536 
537 		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
538 		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
539 		    (arg & TIOCM_CD && (prev.dcd != cur.dcd)) ||
540 		    (arg & TIOCM_CTS && (prev.cts != cur.cts)))
541 			return 0;
542 	}
543 	return 0;
544 }
545 
546 static int qt2_get_icount(struct tty_struct *tty,
547 			  struct serial_icounter_struct *icount)
548 {
549 	struct usb_serial_port *port = tty->driver_data;
550 	struct qt2_port_private *priv = usb_get_serial_port_data(port);
551 	struct async_icount cnow = priv->icount;
552 
553 	icount->cts = cnow.cts;
554 	icount->dsr = cnow.dsr;
555 	icount->rng = cnow.rng;
556 	icount->dcd = cnow.dcd;
557 	icount->rx = cnow.rx;
558 	icount->tx = cnow.tx;
559 	icount->frame = cnow.frame;
560 	icount->overrun = cnow.overrun;
561 	icount->parity = cnow.parity;
562 	icount->brk = cnow.brk;
563 	icount->buf_overrun = cnow.buf_overrun;
564 
565 	return 0;
566 }
567 
568 static int qt2_ioctl(struct tty_struct *tty,
569 		     unsigned int cmd, unsigned long arg)
570 {
571 	struct usb_serial_port *port = tty->driver_data;
572 
573 	switch (cmd) {
574 	case TIOCGSERIAL:
575 		return get_serial_info(port,
576 				       (struct serial_struct __user *)arg);
577 
578 	case TIOCMIWAIT:
579 		return wait_modem_info(port, arg);
580 
581 	default:
582 		break;
583 	}
584 
585 	return -ENOIOCTLCMD;
586 }
587 
588 static void qt2_process_status(struct usb_serial_port *port, unsigned char *ch)
589 {
590 	switch (*ch) {
591 	case QT2_LINE_STATUS:
592 		qt2_update_lsr(port, ch + 1);
593 		break;
594 	case QT2_MODEM_STATUS:
595 		qt2_update_msr(port, ch + 1);
596 		break;
597 	}
598 }
599 
600 /* not needed, kept to document functionality */
601 static void qt2_process_xmit_empty(struct usb_serial_port *port,
602 				   unsigned char *ch)
603 {
604 	int bytes_written;
605 
606 	bytes_written = (int)(*ch) + (int)(*(ch + 1) << 4);
607 }
608 
609 /* not needed, kept to document functionality */
610 static void qt2_process_flush(struct usb_serial_port *port, unsigned char *ch)
611 {
612 	return;
613 }
614 
615 void qt2_process_read_urb(struct urb *urb)
616 {
617 	struct usb_serial *serial;
618 	struct qt2_serial_private *serial_priv;
619 	struct usb_serial_port *port;
620 	struct qt2_port_private *port_priv;
621 	struct tty_struct *tty;
622 	bool escapeflag;
623 	unsigned char *ch;
624 	int i;
625 	unsigned char newport;
626 	int len = urb->actual_length;
627 
628 	if (!len)
629 		return;
630 
631 	ch = urb->transfer_buffer;
632 	tty = NULL;
633 	serial = urb->context;
634 	serial_priv = usb_get_serial_data(serial);
635 	port = serial->port[serial_priv->current_port];
636 	port_priv = usb_get_serial_port_data(port);
637 
638 	if (port_priv->is_open)
639 		tty = tty_port_tty_get(&port->port);
640 
641 	for (i = 0; i < urb->actual_length; i++) {
642 		ch = (unsigned char *)urb->transfer_buffer + i;
643 		if ((i <= (len - 3)) &&
644 		    (*ch == QT2_CONTROL_BYTE) &&
645 		    (*(ch + 1) == QT2_CONTROL_BYTE)) {
646 			escapeflag = false;
647 			switch (*(ch + 2)) {
648 			case QT2_LINE_STATUS:
649 			case QT2_MODEM_STATUS:
650 				if (i > (len - 4)) {
651 					dev_warn(&port->dev,
652 						 "%s - status message too short\n",
653 						__func__);
654 					break;
655 				}
656 				qt2_process_status(port, ch + 2);
657 				i += 3;
658 				escapeflag = true;
659 				break;
660 			case QT2_XMIT_HOLD:
661 				if (i > (len - 5)) {
662 					dev_warn(&port->dev,
663 						 "%s - xmit_empty message too short\n",
664 						 __func__);
665 					break;
666 				}
667 				qt2_process_xmit_empty(port, ch + 3);
668 				i += 4;
669 				escapeflag = true;
670 				break;
671 			case QT2_CHANGE_PORT:
672 				if (i > (len - 4)) {
673 					dev_warn(&port->dev,
674 						 "%s - change_port message too short\n",
675 						 __func__);
676 					break;
677 				}
678 				if (tty) {
679 					tty_flip_buffer_push(tty);
680 					tty_kref_put(tty);
681 				}
682 
683 				newport = *(ch + 3);
684 
685 				if (newport > serial->num_ports) {
686 					dev_err(&port->dev,
687 						"%s - port change to invalid port: %i\n",
688 						__func__, newport);
689 					break;
690 				}
691 
692 				serial_priv->current_port = newport;
693 				port = serial->port[serial_priv->current_port];
694 				port_priv = usb_get_serial_port_data(port);
695 				if (port_priv->is_open)
696 					tty = tty_port_tty_get(&port->port);
697 				else
698 					tty = NULL;
699 				i += 3;
700 				escapeflag = true;
701 				break;
702 			case QT2_REC_FLUSH:
703 			case QT2_XMIT_FLUSH:
704 				qt2_process_flush(port, ch + 2);
705 				i += 2;
706 				escapeflag = true;
707 				break;
708 			case QT2_CONTROL_ESCAPE:
709 				tty_buffer_request_room(tty, 2);
710 				tty_insert_flip_string(tty, ch, 2);
711 				i += 2;
712 				escapeflag = true;
713 				break;
714 			default:
715 				dev_warn(&port->dev,
716 					 "%s - unsupported command %i\n",
717 					 __func__, *(ch + 2));
718 				break;
719 			}
720 			if (escapeflag)
721 				continue;
722 		}
723 
724 		if (tty) {
725 			tty_buffer_request_room(tty, 1);
726 			tty_insert_flip_string(tty, ch, 1);
727 		}
728 	}
729 
730 	if (tty) {
731 		tty_flip_buffer_push(tty);
732 		tty_kref_put(tty);
733 	}
734 }
735 
736 static void qt2_write_bulk_callback(struct urb *urb)
737 {
738 	struct usb_serial_port *port;
739 	struct qt2_port_private *port_priv;
740 
741 	port = urb->context;
742 	port_priv = usb_get_serial_port_data(port);
743 
744 	spin_lock(&port_priv->urb_lock);
745 
746 	port_priv->urb_in_use = false;
747 	usb_serial_port_softint(port);
748 
749 	spin_unlock(&port_priv->urb_lock);
750 
751 }
752 
753 static void qt2_read_bulk_callback(struct urb *urb)
754 {
755 	struct usb_serial *serial = urb->context;
756 	int status;
757 
758 	if (urb->status) {
759 		dev_warn(&serial->dev->dev,
760 			 "%s - non-zero urb status: %i\n", __func__,
761 			 urb->status);
762 		return;
763 	}
764 
765 	qt2_process_read_urb(urb);
766 
767 	status = usb_submit_urb(urb, GFP_ATOMIC);
768 	if (status != 0)
769 		dev_err(&serial->dev->dev,
770 			"%s - resubmit read urb failed: %i\n",
771 			__func__, status);
772 }
773 
774 static int qt2_setup_urbs(struct usb_serial *serial)
775 {
776 	struct usb_serial_port *port;
777 	struct usb_serial_port *port0;
778 	struct qt2_serial_private *serial_priv;
779 	struct qt2_port_private *port_priv;
780 	int pcount, status;
781 
782 	port0 = serial->port[0];
783 
784 	serial_priv = usb_get_serial_data(serial);
785 	serial_priv->read_urb = usb_alloc_urb(0, GFP_KERNEL);
786 	if (!serial_priv->read_urb) {
787 		dev_err(&serial->dev->dev, "No free urbs available\n");
788 		return -ENOMEM;
789 	}
790 
791 	usb_fill_bulk_urb(serial_priv->read_urb, serial->dev,
792 			  usb_rcvbulkpipe(serial->dev,
793 					  port0->bulk_in_endpointAddress),
794 			  serial_priv->read_buffer,
795 			  sizeof(serial_priv->read_buffer),
796 			  qt2_read_bulk_callback, serial);
797 
798 	/* setup write_urb for each port */
799 	for (pcount = 0; pcount < serial->num_ports; pcount++) {
800 
801 		port = serial->port[pcount];
802 		port_priv = usb_get_serial_port_data(port);
803 
804 		port_priv->write_urb = usb_alloc_urb(0, GFP_KERNEL);
805 		if (!port_priv->write_urb) {
806 			dev_err(&serial->dev->dev,
807 				"failed to alloc write_urb for port %i\n",
808 				pcount);
809 			return -ENOMEM;
810 		}
811 
812 		usb_fill_bulk_urb(port_priv->write_urb,
813 				  serial->dev,
814 				  usb_sndbulkpipe(serial->dev,
815 						  port0->
816 						  bulk_out_endpointAddress),
817 				  port_priv->write_buffer,
818 				  sizeof(port_priv->write_buffer),
819 				  qt2_write_bulk_callback, port);
820 	}
821 
822 	status = usb_submit_urb(serial_priv->read_urb, GFP_KERNEL);
823 	if (status != 0) {
824 		dev_err(&serial->dev->dev,
825 			"%s - submit read urb failed %i\n", __func__, status);
826 		return status;
827 	}
828 
829 	return 0;
830 
831 }
832 
833 static int qt2_attach(struct usb_serial *serial)
834 {
835 	struct qt2_serial_private *serial_priv;
836 	struct qt2_port_private *port_priv;
837 	int status, pcount;
838 
839 	/* power on unit */
840 	status = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
841 				 0xc2, 0x40, 0x8000, 0, NULL, 0,
842 				 QT2_USB_TIMEOUT);
843 	if (status < 0) {
844 		dev_err(&serial->dev->dev,
845 			"%s - failed to power on unit: %i\n", __func__, status);
846 		return status;
847 	}
848 
849 	serial_priv = kzalloc(sizeof(*serial_priv), GFP_KERNEL);
850 	if (!serial_priv) {
851 		dev_err(&serial->dev->dev, "%s - Out of memory\n", __func__);
852 		return -ENOMEM;
853 	}
854 
855 	usb_set_serial_data(serial, serial_priv);
856 
857 	for (pcount = 0; pcount < serial->num_ports; pcount++) {
858 		port_priv = kzalloc(sizeof(*port_priv), GFP_KERNEL);
859 		if (!port_priv) {
860 			dev_err(&serial->dev->dev,
861 				"%s- kmalloc(%Zd) failed.\n", __func__,
862 				sizeof(*port_priv));
863 			pcount--;
864 			status = -ENOMEM;
865 			goto attach_failed;
866 		}
867 
868 		spin_lock_init(&port_priv->lock);
869 		spin_lock_init(&port_priv->urb_lock);
870 		init_waitqueue_head(&port_priv->delta_msr_wait);
871 
872 		port_priv->port = serial->port[pcount];
873 
874 		usb_set_serial_port_data(serial->port[pcount], port_priv);
875 	}
876 
877 	status = qt2_setup_urbs(serial);
878 	if (status != 0)
879 		goto attach_failed;
880 
881 	return 0;
882 
883 attach_failed:
884 	for (/* empty */; pcount >= 0; pcount--) {
885 		port_priv = usb_get_serial_port_data(serial->port[pcount]);
886 		kfree(port_priv);
887 	}
888 	kfree(serial_priv);
889 	return status;
890 }
891 
892 static int qt2_tiocmget(struct tty_struct *tty)
893 {
894 	struct usb_serial_port *port = tty->driver_data;
895 	struct usb_device *dev = port->serial->dev;
896 	struct qt2_port_private *port_priv = usb_get_serial_port_data(port);
897 	u8 *d;
898 	int r;
899 
900 	d = kzalloc(2, GFP_KERNEL);
901 	if (!d)
902 		return -ENOMEM;
903 
904 	r = qt2_getregister(dev, port_priv->device_port, UART_MCR, d);
905 	if (r < 0)
906 		goto mget_out;
907 
908 	r = qt2_getregister(dev, port_priv->device_port, UART_MSR, d + 1);
909 	if (r < 0)
910 		goto mget_out;
911 
912 	r = (d[0] & UART_MCR_DTR ? TIOCM_DTR : 0) |
913 	    (d[0] & UART_MCR_RTS ? TIOCM_RTS : 0) |
914 	    (d[1] & UART_MSR_CTS ? TIOCM_CTS : 0) |
915 	    (d[1] & UART_MSR_DCD ? TIOCM_CAR : 0) |
916 	    (d[1] & UART_MSR_RI ? TIOCM_RI : 0) |
917 	    (d[1] & UART_MSR_DSR ? TIOCM_DSR : 0);
918 
919 mget_out:
920 	kfree(d);
921 	return r;
922 }
923 
924 static int qt2_tiocmset(struct tty_struct *tty,
925 			unsigned int set, unsigned int clear)
926 {
927 	struct qt2_port_private *port_priv;
928 
929 	port_priv = usb_get_serial_port_data(tty->driver_data);
930 	return update_mctrl(port_priv, set, clear);
931 }
932 
933 static void qt2_break_ctl(struct tty_struct *tty, int break_state)
934 {
935 	struct usb_serial_port *port = tty->driver_data;
936 	struct qt2_port_private *port_priv;
937 	int status;
938 	u16 val;
939 
940 	port_priv = usb_get_serial_port_data(port);
941 
942 	if (!port_priv->is_open) {
943 		dev_err(&port->dev,
944 			"%s - port is not open\n", __func__);
945 		return;
946 	}
947 
948 	val = (break_state == -1) ? 1 : 0;
949 
950 	status = qt2_control_msg(port->serial->dev, QT2_BREAK_CONTROL,
951 				 val, port_priv->device_port);
952 	if (status < 0)
953 		dev_warn(&port->dev,
954 			 "%s - failed to send control message: %i\n", __func__,
955 			 status);
956 }
957 
958 
959 
960 static void qt2_dtr_rts(struct usb_serial_port *port, int on)
961 {
962 	struct usb_device *dev = port->serial->dev;
963 	struct qt2_port_private *port_priv = usb_get_serial_port_data(port);
964 
965 	mutex_lock(&port->serial->disc_mutex);
966 	if (!port->serial->disconnected) {
967 		/* Disable flow control */
968 		if (!on && qt2_setregister(dev, port_priv->device_port,
969 					   UART_MCR, 0) < 0)
970 			dev_warn(&port->dev, "error from flowcontrol urb\n");
971 		/* drop RTS and DTR */
972 		if (on)
973 			update_mctrl(port_priv, TIOCM_DTR | TIOCM_RTS, 0);
974 		else
975 			update_mctrl(port_priv, 0, TIOCM_DTR | TIOCM_RTS);
976 	}
977 	mutex_unlock(&port->serial->disc_mutex);
978 }
979 
980 static void qt2_update_msr(struct usb_serial_port *port, unsigned char *ch)
981 {
982 	struct qt2_port_private *port_priv;
983 	u8 newMSR = (u8) *ch;
984 	unsigned long flags;
985 
986 	port_priv = usb_get_serial_port_data(port);
987 
988 	spin_lock_irqsave(&port_priv->lock, flags);
989 	port_priv->shadowMSR = newMSR;
990 	spin_unlock_irqrestore(&port_priv->lock, flags);
991 
992 	if (newMSR & UART_MSR_ANY_DELTA) {
993 		/* update input line counters */
994 		if (newMSR & UART_MSR_DCTS)
995 			port_priv->icount.cts++;
996 
997 		if (newMSR & UART_MSR_DDSR)
998 			port_priv->icount.dsr++;
999 
1000 		if (newMSR & UART_MSR_DDCD)
1001 			port_priv->icount.dcd++;
1002 
1003 		if (newMSR & UART_MSR_TERI)
1004 			port_priv->icount.rng++;
1005 
1006 		wake_up_interruptible(&port_priv->delta_msr_wait);
1007 	}
1008 }
1009 
1010 static void qt2_update_lsr(struct usb_serial_port *port, unsigned char *ch)
1011 {
1012 	struct qt2_port_private *port_priv;
1013 	struct async_icount *icount;
1014 	unsigned long flags;
1015 	u8 newLSR = (u8) *ch;
1016 
1017 	port_priv = usb_get_serial_port_data(port);
1018 
1019 	if (newLSR & UART_LSR_BI)
1020 		newLSR &= (u8) (UART_LSR_OE | UART_LSR_BI);
1021 
1022 	spin_lock_irqsave(&port_priv->lock, flags);
1023 	port_priv->shadowLSR = newLSR;
1024 	spin_unlock_irqrestore(&port_priv->lock, flags);
1025 
1026 	icount = &port_priv->icount;
1027 
1028 	if (newLSR & UART_LSR_BRK_ERROR_BITS) {
1029 
1030 		if (newLSR & UART_LSR_BI)
1031 			icount->brk++;
1032 
1033 		if (newLSR & UART_LSR_OE)
1034 			icount->overrun++;
1035 
1036 		if (newLSR & UART_LSR_PE)
1037 			icount->parity++;
1038 
1039 		if (newLSR & UART_LSR_FE)
1040 			icount->frame++;
1041 	}
1042 
1043 }
1044 
1045 static int qt2_write_room(struct tty_struct *tty)
1046 {
1047 	struct usb_serial_port *port = tty->driver_data;
1048 	struct qt2_port_private *port_priv;
1049 	unsigned long flags = 0;
1050 	int r;
1051 
1052 	port_priv = usb_get_serial_port_data(port);
1053 
1054 	spin_lock_irqsave(&port_priv->urb_lock, flags);
1055 
1056 	if (port_priv->urb_in_use)
1057 		r = 0;
1058 	else
1059 		r = QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE;
1060 
1061 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
1062 
1063 	return r;
1064 }
1065 
1066 static int qt2_write(struct tty_struct *tty,
1067 		     struct usb_serial_port *port,
1068 		     const unsigned char *buf, int count)
1069 {
1070 	struct qt2_port_private *port_priv;
1071 	struct urb *write_urb;
1072 	unsigned char *data;
1073 	unsigned long flags;
1074 	int status;
1075 	int bytes_out = 0;
1076 
1077 	port_priv = usb_get_serial_port_data(port);
1078 
1079 	if (port_priv->write_urb == NULL) {
1080 		dev_err(&port->dev, "%s - no output urb\n", __func__);
1081 		return 0;
1082 	}
1083 	write_urb = port_priv->write_urb;
1084 
1085 	count = min(count, QT2_WRITE_BUFFER_SIZE - QT2_WRITE_CONTROL_SIZE);
1086 
1087 	data = write_urb->transfer_buffer;
1088 	spin_lock_irqsave(&port_priv->urb_lock, flags);
1089 	if (port_priv->urb_in_use == true) {
1090 		dev_err(&port->dev, "qt2_write - urb is in use\n");
1091 		goto write_out;
1092 	}
1093 
1094 	*data++ = QT2_CONTROL_BYTE;
1095 	*data++ = QT2_CONTROL_BYTE;
1096 	*data++ = port_priv->device_port;
1097 	put_unaligned_le16(count, data);
1098 	data += 2;
1099 	memcpy(data, buf, count);
1100 
1101 	write_urb->transfer_buffer_length = count + QT2_WRITE_CONTROL_SIZE;
1102 
1103 	status = usb_submit_urb(write_urb, GFP_ATOMIC);
1104 	if (status == 0) {
1105 		port_priv->urb_in_use = true;
1106 		bytes_out += count;
1107 	}
1108 
1109 write_out:
1110 	spin_unlock_irqrestore(&port_priv->urb_lock, flags);
1111 	return bytes_out;
1112 }
1113 
1114 
1115 static struct usb_serial_driver qt2_device = {
1116 	.driver = {
1117 		.owner = THIS_MODULE,
1118 		.name = "quatech-serial",
1119 	},
1120 	.description	     = DRIVER_DESC,
1121 	.id_table	     = id_table,
1122 	.open		     = qt2_open,
1123 	.close		     = qt2_close,
1124 	.write               = qt2_write,
1125 	.write_room          = qt2_write_room,
1126 	.calc_num_ports      = qt2_calc_num_ports,
1127 	.attach              = qt2_attach,
1128 	.release             = qt2_release,
1129 	.disconnect          = qt2_disconnect,
1130 	.dtr_rts             = qt2_dtr_rts,
1131 	.break_ctl           = qt2_break_ctl,
1132 	.tiocmget            = qt2_tiocmget,
1133 	.tiocmset            = qt2_tiocmset,
1134 	.get_icount	     = qt2_get_icount,
1135 	.ioctl               = qt2_ioctl,
1136 	.set_termios         = qt2_set_termios,
1137 };
1138 
1139 static struct usb_serial_driver *const serial_drivers[] = {
1140 	&qt2_device, NULL
1141 };
1142 
1143 module_usb_serial_driver(serial_drivers, id_table);
1144 
1145 MODULE_DESCRIPTION(DRIVER_DESC);
1146 MODULE_LICENSE("GPL");
1147