xref: /openbmc/linux/drivers/usb/serial/ssu100.c (revision 0bca1b913affbd7e2fdaffee62a499659a466eb5)
1 /*
2  * usb-serial driver for Quatech SSU-100
3  *
4  * based on ftdi_sio.c and the original serqt_usb.c from Quatech
5  *
6  */
7 
8 #include <linux/errno.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/tty.h>
12 #include <linux/tty_driver.h>
13 #include <linux/tty_flip.h>
14 #include <linux/module.h>
15 #include <linux/serial.h>
16 #include <linux/usb.h>
17 #include <linux/usb/serial.h>
18 #include <linux/serial_reg.h>
19 #include <linux/uaccess.h>
20 
21 #define QT_OPEN_CLOSE_CHANNEL       0xca
22 #define QT_SET_GET_DEVICE           0xc2
23 #define QT_SET_GET_REGISTER         0xc0
24 #define QT_GET_SET_PREBUF_TRIG_LVL  0xcc
25 #define QT_SET_ATF                  0xcd
26 #define QT_GET_SET_UART             0xc1
27 #define QT_TRANSFER_IN              0xc0
28 #define QT_HW_FLOW_CONTROL_MASK     0xc5
29 #define QT_SW_FLOW_CONTROL_MASK     0xc6
30 
31 #define  SERIAL_MSR_MASK            0xf0
32 
33 #define  SERIAL_CRTSCTS ((UART_MCR_RTS << 8) | UART_MSR_CTS)
34 
35 #define  SERIAL_EVEN_PARITY         (UART_LCR_PARITY | UART_LCR_EPAR)
36 
37 #define  MAX_BAUD_RATE              460800
38 
39 #define ATC_DISABLED                0x00
40 #define DUPMODE_BITS        0xc0
41 #define RR_BITS             0x03
42 #define LOOPMODE_BITS       0x41
43 #define RS232_MODE          0x00
44 #define RTSCTS_TO_CONNECTOR 0x40
45 #define CLKS_X4             0x02
46 #define FULLPWRBIT          0x00000080
47 #define NEXT_BOARD_POWER_BIT        0x00000004
48 
49 static int debug;
50 
51 /* Version Information */
52 #define DRIVER_VERSION "v0.1"
53 #define DRIVER_DESC "Quatech SSU-100 USB to Serial Driver"
54 
55 #define	USB_VENDOR_ID_QUATECH	0x061d	/* Quatech VID */
56 #define QUATECH_SSU100	0xC020	/* SSU100 */
57 
58 static const struct usb_device_id id_table[] = {
59 	{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_SSU100)},
60 	{}			/* Terminating entry */
61 };
62 
63 MODULE_DEVICE_TABLE(usb, id_table);
64 
65 
66 static struct usb_driver ssu100_driver = {
67 	.name			       = "ssu100",
68 	.probe			       = usb_serial_probe,
69 	.disconnect		       = usb_serial_disconnect,
70 	.id_table		       = id_table,
71 	.suspend		       = usb_serial_suspend,
72 	.resume			       = usb_serial_resume,
73 	.no_dynamic_id		       = 1,
74 	.supports_autosuspend	       = 1,
75 };
76 
77 struct ssu100_port_private {
78 	spinlock_t status_lock;
79 	u8 shadowLSR;
80 	u8 shadowMSR;
81 	wait_queue_head_t delta_msr_wait; /* Used for TIOCMIWAIT */
82 	unsigned short max_packet_size;
83 	struct async_icount icount;
84 };
85 
86 static void ssu100_release(struct usb_serial *serial)
87 {
88 	struct ssu100_port_private *priv = usb_get_serial_port_data(*serial->port);
89 
90 	dbg("%s", __func__);
91 	kfree(priv);
92 }
93 
94 static inline int ssu100_control_msg(struct usb_device *dev,
95 				     u8 request, u16 data, u16 index)
96 {
97 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
98 			       request, 0x40, data, index,
99 			       NULL, 0, 300);
100 }
101 
102 static inline int ssu100_setdevice(struct usb_device *dev, u8 *data)
103 {
104 	u16 x = ((u16)(data[1] << 8) | (u16)(data[0]));
105 
106 	return ssu100_control_msg(dev, QT_SET_GET_DEVICE, x, 0);
107 }
108 
109 
110 static inline int ssu100_getdevice(struct usb_device *dev, u8 *data)
111 {
112 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
113 			       QT_SET_GET_DEVICE, 0xc0, 0, 0,
114 			       data, 3, 300);
115 }
116 
117 static inline int ssu100_getregister(struct usb_device *dev,
118 				     unsigned short uart,
119 				     unsigned short reg,
120 				     u8 *data)
121 {
122 	return usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
123 			       QT_SET_GET_REGISTER, 0xc0, reg,
124 			       uart, data, sizeof(*data), 300);
125 
126 }
127 
128 
129 static inline int ssu100_setregister(struct usb_device *dev,
130 				     unsigned short uart,
131 				     unsigned short reg,
132 				     u16 data)
133 {
134 	u16 value = (data << 8) | reg;
135 
136 	return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
137 			       QT_SET_GET_REGISTER, 0x40, value, uart,
138 			       NULL, 0, 300);
139 
140 }
141 
142 #define set_mctrl(dev, set)		update_mctrl((dev), (set), 0)
143 #define clear_mctrl(dev, clear)	update_mctrl((dev), 0, (clear))
144 
145 /* these do not deal with device that have more than 1 port */
146 static inline int update_mctrl(struct usb_device *dev, unsigned int set,
147 			       unsigned int clear)
148 {
149 	unsigned urb_value;
150 	int result;
151 
152 	if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) {
153 		dbg("%s - DTR|RTS not being set|cleared", __func__);
154 		return 0;	/* no change */
155 	}
156 
157 	clear &= ~set;	/* 'set' takes precedence over 'clear' */
158 	urb_value = 0;
159 	if (set & TIOCM_DTR)
160 		urb_value |= UART_MCR_DTR;
161 	if (set & TIOCM_RTS)
162 		urb_value |= UART_MCR_RTS;
163 
164 	result = ssu100_setregister(dev, 0, UART_MCR, urb_value);
165 	if (result < 0)
166 		dbg("%s Error from MODEM_CTRL urb", __func__);
167 
168 	return result;
169 }
170 
171 static int ssu100_initdevice(struct usb_device *dev)
172 {
173 	u8 *data;
174 	int result = 0;
175 
176 	dbg("%s", __func__);
177 
178 	data = kzalloc(3, GFP_KERNEL);
179 	if (!data)
180 		return -ENOMEM;
181 
182 	result = ssu100_getdevice(dev, data);
183 	if (result < 0) {
184 		dbg("%s - get_device failed %i", __func__, result);
185 		goto out;
186 	}
187 
188 	data[1] &= ~FULLPWRBIT;
189 
190 	result = ssu100_setdevice(dev, data);
191 	if (result < 0) {
192 		dbg("%s - setdevice failed %i", __func__, result);
193 		goto out;
194 	}
195 
196 	result = ssu100_control_msg(dev, QT_GET_SET_PREBUF_TRIG_LVL, 128, 0);
197 	if (result < 0) {
198 		dbg("%s - set prebuffer level failed %i", __func__, result);
199 		goto out;
200 	}
201 
202 	result = ssu100_control_msg(dev, QT_SET_ATF, ATC_DISABLED, 0);
203 	if (result < 0) {
204 		dbg("%s - set ATFprebuffer level failed %i", __func__, result);
205 		goto out;
206 	}
207 
208 	result = ssu100_getdevice(dev, data);
209 	if (result < 0) {
210 		dbg("%s - get_device failed %i", __func__, result);
211 		goto out;
212 	}
213 
214 	data[0] &= ~(RR_BITS | DUPMODE_BITS);
215 	data[0] |= CLKS_X4;
216 	data[1] &= ~(LOOPMODE_BITS);
217 	data[1] |= RS232_MODE;
218 
219 	result = ssu100_setdevice(dev, data);
220 	if (result < 0) {
221 		dbg("%s - setdevice failed %i", __func__, result);
222 		goto out;
223 	}
224 
225 out:	kfree(data);
226 	return result;
227 
228 }
229 
230 
231 static void ssu100_set_termios(struct tty_struct *tty,
232 			       struct usb_serial_port *port,
233 			       struct ktermios *old_termios)
234 {
235 	struct usb_device *dev = port->serial->dev;
236 	struct ktermios *termios = tty->termios;
237 	u16 baud, divisor, remainder;
238 	unsigned int cflag = termios->c_cflag;
239 	u16 urb_value = 0; /* will hold the new flags */
240 	int result;
241 
242 	dbg("%s", __func__);
243 
244 	if (cflag & PARENB) {
245 		if (cflag & PARODD)
246 			urb_value |= UART_LCR_PARITY;
247 		else
248 			urb_value |= SERIAL_EVEN_PARITY;
249 	}
250 
251 	switch (cflag & CSIZE) {
252 	case CS5:
253 		urb_value |= UART_LCR_WLEN5;
254 		break;
255 	case CS6:
256 		urb_value |= UART_LCR_WLEN6;
257 		break;
258 	case CS7:
259 		urb_value |= UART_LCR_WLEN7;
260 		break;
261 	default:
262 	case CS8:
263 		urb_value |= UART_LCR_WLEN8;
264 		break;
265 	}
266 
267 	baud = tty_get_baud_rate(tty);
268 	if (!baud)
269 		baud = 9600;
270 
271 	dbg("%s - got baud = %d\n", __func__, baud);
272 
273 
274 	divisor = MAX_BAUD_RATE / baud;
275 	remainder = MAX_BAUD_RATE % baud;
276 	if (((remainder * 2) >= baud) && (baud != 110))
277 		divisor++;
278 
279 	urb_value = urb_value << 8;
280 
281 	result = ssu100_control_msg(dev, QT_GET_SET_UART, divisor, urb_value);
282 	if (result < 0)
283 		dbg("%s - set uart failed", __func__);
284 
285 	if (cflag & CRTSCTS)
286 		result = ssu100_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
287 					    SERIAL_CRTSCTS, 0);
288 	else
289 		result = ssu100_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
290 					    0, 0);
291 	if (result < 0)
292 		dbg("%s - set HW flow control failed", __func__);
293 
294 	if (I_IXOFF(tty) || I_IXON(tty)) {
295 		u16 x = ((u16)(START_CHAR(tty) << 8) | (u16)(STOP_CHAR(tty)));
296 
297 		result = ssu100_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
298 					    x, 0);
299 	} else
300 		result = ssu100_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
301 					    0, 0);
302 
303 	if (result < 0)
304 		dbg("%s - set SW flow control failed", __func__);
305 
306 }
307 
308 
309 static int ssu100_open(struct tty_struct *tty, struct usb_serial_port *port)
310 {
311 	struct usb_device *dev = port->serial->dev;
312 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
313 	u8 *data;
314 	int result;
315 	unsigned long flags;
316 
317 	dbg("%s - port %d", __func__, port->number);
318 
319 	data = kzalloc(2, GFP_KERNEL);
320 	if (!data)
321 		return -ENOMEM;
322 
323 	result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
324 				 QT_OPEN_CLOSE_CHANNEL,
325 				 QT_TRANSFER_IN, 0x01,
326 				 0, data, 2, 300);
327 	if (result < 0) {
328 		dbg("%s - open failed %i", __func__, result);
329 		kfree(data);
330 		return result;
331 	}
332 
333 	spin_lock_irqsave(&priv->status_lock, flags);
334 	priv->shadowLSR = data[0];
335 	priv->shadowMSR = data[1];
336 	spin_unlock_irqrestore(&priv->status_lock, flags);
337 
338 	kfree(data);
339 
340 /* set to 9600 */
341 	result = ssu100_control_msg(dev, QT_GET_SET_UART, 0x30, 0x0300);
342 	if (result < 0)
343 		dbg("%s - set uart failed", __func__);
344 
345 	if (tty)
346 		ssu100_set_termios(tty, port, tty->termios);
347 
348 	return usb_serial_generic_open(tty, port);
349 }
350 
351 static void ssu100_close(struct usb_serial_port *port)
352 {
353 	dbg("%s", __func__);
354 	usb_serial_generic_close(port);
355 }
356 
357 static int get_serial_info(struct usb_serial_port *port,
358 			   struct serial_struct __user *retinfo)
359 {
360 	struct serial_struct tmp;
361 
362 	if (!retinfo)
363 		return -EFAULT;
364 
365 	memset(&tmp, 0, sizeof(tmp));
366 	tmp.line		= port->serial->minor;
367 	tmp.port		= 0;
368 	tmp.irq			= 0;
369 	tmp.flags		= ASYNC_SKIP_TEST | ASYNC_AUTO_IRQ;
370 	tmp.xmit_fifo_size	= port->bulk_out_size;
371 	tmp.baud_base		= 9600;
372 	tmp.close_delay		= 5*HZ;
373 	tmp.closing_wait	= 30*HZ;
374 
375 	if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
376 		return -EFAULT;
377 	return 0;
378 }
379 
380 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
381 {
382 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
383 	struct async_icount prev, cur;
384 	unsigned long flags;
385 
386 	spin_lock_irqsave(&priv->status_lock, flags);
387 	prev = priv->icount;
388 	spin_unlock_irqrestore(&priv->status_lock, flags);
389 
390 	while (1) {
391 		wait_event_interruptible(priv->delta_msr_wait,
392 					 ((priv->icount.rng != prev.rng) ||
393 					  (priv->icount.dsr != prev.dsr) ||
394 					  (priv->icount.dcd != prev.dcd) ||
395 					  (priv->icount.cts != prev.cts)));
396 
397 		if (signal_pending(current))
398 			return -ERESTARTSYS;
399 
400 		spin_lock_irqsave(&priv->status_lock, flags);
401 		cur = priv->icount;
402 		spin_unlock_irqrestore(&priv->status_lock, flags);
403 
404 		if ((prev.rng == cur.rng) &&
405 		    (prev.dsr == cur.dsr) &&
406 		    (prev.dcd == cur.dcd) &&
407 		    (prev.cts == cur.cts))
408 			return -EIO;
409 
410 		if ((arg & TIOCM_RNG && (prev.rng != cur.rng)) ||
411 		    (arg & TIOCM_DSR && (prev.dsr != cur.dsr)) ||
412 		    (arg & TIOCM_CD  && (prev.dcd != cur.dcd)) ||
413 		    (arg & TIOCM_CTS && (prev.cts != cur.cts)))
414 			return 0;
415 	}
416 	return 0;
417 }
418 
419 static int ssu100_get_icount(struct tty_struct *tty,
420 			struct serial_icounter_struct *icount)
421 {
422 	struct usb_serial_port *port = tty->driver_data;
423 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
424 	struct async_icount cnow = priv->icount;
425 
426 	icount->cts = cnow.cts;
427 	icount->dsr = cnow.dsr;
428 	icount->rng = cnow.rng;
429 	icount->dcd = cnow.dcd;
430 	icount->rx = cnow.rx;
431 	icount->tx = cnow.tx;
432 	icount->frame = cnow.frame;
433 	icount->overrun = cnow.overrun;
434 	icount->parity = cnow.parity;
435 	icount->brk = cnow.brk;
436 	icount->buf_overrun = cnow.buf_overrun;
437 
438 	return 0;
439 }
440 
441 
442 
443 static int ssu100_ioctl(struct tty_struct *tty, struct file *file,
444 		    unsigned int cmd, unsigned long arg)
445 {
446 	struct usb_serial_port *port = tty->driver_data;
447 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
448 	void __user *user_arg = (void __user *)arg;
449 
450 	dbg("%s cmd 0x%04x", __func__, cmd);
451 
452 	switch (cmd) {
453 	case TIOCGSERIAL:
454 		return get_serial_info(port,
455 				       (struct serial_struct __user *) arg);
456 
457 	case TIOCMIWAIT:
458 		return wait_modem_info(port, arg);
459 
460 	default:
461 		break;
462 	}
463 
464 	dbg("%s arg not supported", __func__);
465 
466 	return -ENOIOCTLCMD;
467 }
468 
469 static void ssu100_set_max_packet_size(struct usb_serial_port *port)
470 {
471 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
472 	struct usb_serial *serial = port->serial;
473 	struct usb_device *udev = serial->dev;
474 
475 	struct usb_interface *interface = serial->interface;
476 	struct usb_endpoint_descriptor *ep_desc = &interface->cur_altsetting->endpoint[1].desc;
477 
478 	unsigned num_endpoints;
479 	int i;
480 	unsigned long flags;
481 
482 	num_endpoints = interface->cur_altsetting->desc.bNumEndpoints;
483 	dev_info(&udev->dev, "Number of endpoints %d\n", num_endpoints);
484 
485 	for (i = 0; i < num_endpoints; i++) {
486 		dev_info(&udev->dev, "Endpoint %d MaxPacketSize %d\n", i+1,
487 			interface->cur_altsetting->endpoint[i].desc.wMaxPacketSize);
488 		ep_desc = &interface->cur_altsetting->endpoint[i].desc;
489 	}
490 
491 	/* set max packet size based on descriptor */
492 	spin_lock_irqsave(&priv->status_lock, flags);
493 	priv->max_packet_size = ep_desc->wMaxPacketSize;
494 	spin_unlock_irqrestore(&priv->status_lock, flags);
495 
496 	dev_info(&udev->dev, "Setting MaxPacketSize %d\n", priv->max_packet_size);
497 }
498 
499 static int ssu100_attach(struct usb_serial *serial)
500 {
501 	struct ssu100_port_private *priv;
502 	struct usb_serial_port *port = *serial->port;
503 
504 	dbg("%s", __func__);
505 
506 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
507 	if (!priv) {
508 		dev_err(&port->dev, "%s- kmalloc(%Zd) failed.\n", __func__,
509 			sizeof(*priv));
510 		return -ENOMEM;
511 	}
512 
513 	spin_lock_init(&priv->status_lock);
514 	init_waitqueue_head(&priv->delta_msr_wait);
515 	usb_set_serial_port_data(port, priv);
516 	ssu100_set_max_packet_size(port);
517 
518 	return ssu100_initdevice(serial->dev);
519 }
520 
521 static int ssu100_tiocmget(struct tty_struct *tty, struct file *file)
522 {
523 	struct usb_serial_port *port = tty->driver_data;
524 	struct usb_device *dev = port->serial->dev;
525 	u8 *d;
526 	int r;
527 
528 	dbg("%s\n", __func__);
529 
530 	d = kzalloc(2, GFP_KERNEL);
531 	if (!d)
532 		return -ENOMEM;
533 
534 	r = ssu100_getregister(dev, 0, UART_MCR, d);
535 	if (r < 0)
536 		goto mget_out;
537 
538 	r = ssu100_getregister(dev, 0, UART_MSR, d+1);
539 	if (r < 0)
540 		goto mget_out;
541 
542 	r = (d[0] & UART_MCR_DTR ? TIOCM_DTR : 0) |
543 		(d[0] & UART_MCR_RTS ? TIOCM_RTS : 0) |
544 		(d[1] & UART_MSR_CTS ? TIOCM_CTS : 0) |
545 		(d[1] & UART_MSR_DCD ? TIOCM_CAR : 0) |
546 		(d[1] & UART_MSR_RI ? TIOCM_RI : 0) |
547 		(d[1] & UART_MSR_DSR ? TIOCM_DSR : 0);
548 
549 mget_out:
550 	kfree(d);
551 	return r;
552 }
553 
554 static int ssu100_tiocmset(struct tty_struct *tty, struct file *file,
555 			   unsigned int set, unsigned int clear)
556 {
557 	struct usb_serial_port *port = tty->driver_data;
558 	struct usb_device *dev = port->serial->dev;
559 
560 	dbg("%s\n", __func__);
561 	return update_mctrl(dev, set, clear);
562 }
563 
564 static void ssu100_dtr_rts(struct usb_serial_port *port, int on)
565 {
566 	struct usb_device *dev = port->serial->dev;
567 
568 	dbg("%s\n", __func__);
569 
570 	mutex_lock(&port->serial->disc_mutex);
571 	if (!port->serial->disconnected) {
572 		/* Disable flow control */
573 		if (!on &&
574 		    ssu100_setregister(dev, 0, UART_MCR, 0) < 0)
575 			dev_err(&port->dev, "error from flowcontrol urb\n");
576 		/* drop RTS and DTR */
577 		if (on)
578 			set_mctrl(dev, TIOCM_DTR | TIOCM_RTS);
579 		else
580 			clear_mctrl(dev, TIOCM_DTR | TIOCM_RTS);
581 	}
582 	mutex_unlock(&port->serial->disc_mutex);
583 }
584 
585 static void ssu100_update_msr(struct usb_serial_port *port, u8 msr)
586 {
587 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
588 	unsigned long flags;
589 
590 	spin_lock_irqsave(&priv->status_lock, flags);
591 	priv->shadowMSR = msr;
592 	spin_unlock_irqrestore(&priv->status_lock, flags);
593 
594 	if (msr & UART_MSR_ANY_DELTA) {
595 		/* update input line counters */
596 		if (msr & UART_MSR_DCTS)
597 			priv->icount.cts++;
598 		if (msr & UART_MSR_DDSR)
599 			priv->icount.dsr++;
600 		if (msr & UART_MSR_DDCD)
601 			priv->icount.dcd++;
602 		if (msr & UART_MSR_TERI)
603 			priv->icount.rng++;
604 		wake_up_interruptible(&priv->delta_msr_wait);
605 	}
606 }
607 
608 static void ssu100_update_lsr(struct usb_serial_port *port, u8 lsr,
609 			      char *tty_flag)
610 {
611 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
612 	unsigned long flags;
613 
614 	spin_lock_irqsave(&priv->status_lock, flags);
615 	priv->shadowLSR = lsr;
616 	spin_unlock_irqrestore(&priv->status_lock, flags);
617 
618 	*tty_flag = TTY_NORMAL;
619 	if (lsr & UART_LSR_BRK_ERROR_BITS) {
620 		/* we always want to update icount, but we only want to
621 		 * update tty_flag for one case */
622 		if (lsr & UART_LSR_BI) {
623 			priv->icount.brk++;
624 			*tty_flag = TTY_BREAK;
625 			usb_serial_handle_break(port);
626 		}
627 		if (lsr & UART_LSR_PE) {
628 			priv->icount.parity++;
629 			if (*tty_flag == TTY_NORMAL)
630 				*tty_flag = TTY_PARITY;
631 		}
632 		if (lsr & UART_LSR_FE) {
633 			priv->icount.frame++;
634 			if (*tty_flag == TTY_NORMAL)
635 				*tty_flag = TTY_FRAME;
636 		}
637 		if (lsr & UART_LSR_OE){
638 			priv->icount.overrun++;
639 			if (*tty_flag == TTY_NORMAL)
640 				*tty_flag = TTY_OVERRUN;
641 		}
642 	}
643 
644 }
645 
646 static int ssu100_process_packet(struct tty_struct *tty,
647 				 struct usb_serial_port *port,
648 				 struct ssu100_port_private *priv,
649 				 char *packet, int len)
650 {
651 	int i;
652 	char flag = TTY_NORMAL;
653 	char *ch;
654 
655 	dbg("%s - port %d", __func__, port->number);
656 
657 	if ((len >= 4) &&
658 	    (packet[0] == 0x1b) && (packet[1] == 0x1b) &&
659 	    ((packet[2] == 0x00) || (packet[2] == 0x01))) {
660 		if (packet[2] == 0x00) {
661 			ssu100_update_lsr(port, packet[3], &flag);
662 			if (flag == TTY_OVERRUN)
663 				tty_insert_flip_char(tty, 0, TTY_OVERRUN);
664 		}
665 		if (packet[2] == 0x01)
666 			ssu100_update_msr(port, packet[3]);
667 
668 		len -= 4;
669 		ch = packet + 4;
670 	} else
671 		ch = packet;
672 
673 	if (!len)
674 		return 0;	/* status only */
675 
676 	if (port->port.console && port->sysrq) {
677 		for (i = 0; i < len; i++, ch++) {
678 			if (!usb_serial_handle_sysrq_char(port, *ch))
679 				tty_insert_flip_char(tty, *ch, flag);
680 		}
681 	} else
682 		tty_insert_flip_string_fixed_flag(tty, ch, flag, len);
683 
684 	return len;
685 }
686 
687 static void ssu100_process_read_urb(struct urb *urb)
688 {
689 	struct usb_serial_port *port = urb->context;
690 	struct ssu100_port_private *priv = usb_get_serial_port_data(port);
691 	char *data = (char *)urb->transfer_buffer;
692 	struct tty_struct *tty;
693 	int count = 0;
694 	int i;
695 	int len;
696 
697 	dbg("%s", __func__);
698 
699 	tty = tty_port_tty_get(&port->port);
700 	if (!tty)
701 		return;
702 
703 	for (i = 0; i < urb->actual_length; i += priv->max_packet_size) {
704 		len = min_t(int, urb->actual_length - i, priv->max_packet_size);
705 		count += ssu100_process_packet(tty, port, priv, &data[i], len);
706 	}
707 
708 	if (count)
709 		tty_flip_buffer_push(tty);
710 	tty_kref_put(tty);
711 }
712 
713 static struct usb_serial_driver ssu100_device = {
714 	.driver = {
715 		.owner = THIS_MODULE,
716 		.name = "ssu100",
717 	},
718 	.description	     = DRIVER_DESC,
719 	.id_table	     = id_table,
720 	.usb_driver	     = &ssu100_driver,
721 	.num_ports	     = 1,
722 	.bulk_in_size        = 256,
723 	.bulk_out_size       = 256,
724 	.open		     = ssu100_open,
725 	.close		     = ssu100_close,
726 	.attach              = ssu100_attach,
727 	.release             = ssu100_release,
728 	.dtr_rts             = ssu100_dtr_rts,
729 	.process_read_urb    = ssu100_process_read_urb,
730 	.tiocmget            = ssu100_tiocmget,
731 	.tiocmset            = ssu100_tiocmset,
732 	.get_icount	     = ssu100_get_icount,
733 	.ioctl               = ssu100_ioctl,
734 	.set_termios         = ssu100_set_termios,
735 	.disconnect          = usb_serial_generic_disconnect,
736 };
737 
738 static int __init ssu100_init(void)
739 {
740 	int retval;
741 
742 	dbg("%s", __func__);
743 
744 	/* register with usb-serial */
745 	retval = usb_serial_register(&ssu100_device);
746 
747 	if (retval)
748 		goto failed_usb_sio_register;
749 
750 	retval = usb_register(&ssu100_driver);
751 	if (retval)
752 		goto failed_usb_register;
753 
754 	printk(KERN_INFO KBUILD_MODNAME ": " DRIVER_VERSION ":"
755 	       DRIVER_DESC "\n");
756 
757 	return 0;
758 
759 failed_usb_register:
760 	usb_serial_deregister(&ssu100_device);
761 failed_usb_sio_register:
762 	return retval;
763 }
764 
765 static void __exit ssu100_exit(void)
766 {
767 	usb_deregister(&ssu100_driver);
768 	usb_serial_deregister(&ssu100_device);
769 }
770 
771 module_init(ssu100_init);
772 module_exit(ssu100_exit);
773 
774 MODULE_DESCRIPTION(DRIVER_DESC);
775 MODULE_LICENSE("GPL");
776 
777 module_param(debug, bool, S_IRUGO | S_IWUSR);
778 MODULE_PARM_DESC(debug, "Debug enabled or not");
779