xref: /linux/drivers/usb/serial/oti6858.c (revision 606b2f490fb80e55d05cf0e6cec0b6c0ff0fc18f)
1 /*
2  * Ours Technology Inc. OTi-6858 USB to serial adapter driver.
3  *
4  * Copyleft  (C) 2007 Kees Lemmens (adapted for kernel 2.6.20)
5  * Copyright (C) 2006 Tomasz Michal Lukaszewski (FIXME: add e-mail)
6  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
7  * Copyright (C) 2003 IBM Corp.
8  *
9  * Many thanks to the authors of pl2303 driver: all functions in this file
10  * are heavily based on pl2303 code, buffering code is a 1-to-1 copy.
11  *
12  * Warning! You use this driver on your own risk! The only official
13  * description of this device I have is datasheet from manufacturer,
14  * and it doesn't contain almost any information needed to write a driver.
15  * Almost all knowlegde used while writing this driver was gathered by:
16  *  - analyzing traffic between device and the M$ Windows 2000 driver,
17  *  - trying different bit combinations and checking pin states
18  *    with a voltmeter,
19  *  - receiving malformed frames and producing buffer overflows
20  *    to learn how errors are reported,
21  * So, THIS CODE CAN DESTROY OTi-6858 AND ANY OTHER DEVICES, THAT ARE
22  * CONNECTED TO IT!
23  *
24  * This program is free software; you can redistribute it and/or modify
25  * it under the terms of the GNU General Public License as published by
26  * the Free Software Foundation; either version 2 of the License.
27  *
28  * See Documentation/usb/usb-serial.txt for more information on using this
29  * driver
30  *
31  * TODO:
32  *  - implement correct flushing for ioctls and oti6858_close()
33  *  - check how errors (rx overflow, parity error, framing error) are reported
34  *  - implement oti6858_break_ctl()
35  *  - implement more ioctls
36  *  - test/implement flow control
37  *  - allow setting custom baud rates
38  */
39 
40 #include <linux/kernel.h>
41 #include <linux/errno.h>
42 #include <linux/init.h>
43 #include <linux/slab.h>
44 #include <linux/tty.h>
45 #include <linux/tty_driver.h>
46 #include <linux/tty_flip.h>
47 #include <linux/serial.h>
48 #include <linux/module.h>
49 #include <linux/moduleparam.h>
50 #include <linux/spinlock.h>
51 #include <linux/usb.h>
52 #include <linux/usb/serial.h>
53 #include <linux/uaccess.h>
54 #include <linux/kfifo.h>
55 #include "oti6858.h"
56 
57 #define OTI6858_DESCRIPTION \
58 	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"
59 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
60 #define OTI6858_VERSION "0.2"
61 
62 static const struct usb_device_id id_table[] = {
63 	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
64 	{ }
65 };
66 
67 MODULE_DEVICE_TABLE(usb, id_table);
68 
69 static struct usb_driver oti6858_driver = {
70 	.name =		"oti6858",
71 	.probe =	usb_serial_probe,
72 	.disconnect =	usb_serial_disconnect,
73 	.id_table =	id_table,
74 	.no_dynamic_id = 	1,
75 };
76 
77 static int debug;
78 
79 /* requests */
80 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
81 #define	OTI6858_REQ_T_GET_STATUS	0x01
82 
83 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
84 #define	OTI6858_REQ_T_SET_LINE		0x00
85 
86 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
87 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
88 
89 /* format of the control packet */
90 struct oti6858_control_pkt {
91 	__le16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
92 #define OTI6858_MAX_BAUD_RATE	3000000
93 	u8	frame_fmt;
94 #define FMT_STOP_BITS_MASK	0xc0
95 #define FMT_STOP_BITS_1		0x00
96 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
97 #define FMT_PARITY_MASK		0x38
98 #define FMT_PARITY_NONE		0x00
99 #define FMT_PARITY_ODD		0x08
100 #define FMT_PARITY_EVEN		0x18
101 #define FMT_PARITY_MARK		0x28
102 #define FMT_PARITY_SPACE	0x38
103 #define FMT_DATA_BITS_MASK	0x03
104 #define FMT_DATA_BITS_5		0x00
105 #define FMT_DATA_BITS_6		0x01
106 #define FMT_DATA_BITS_7		0x02
107 #define FMT_DATA_BITS_8		0x03
108 	u8	something;	/* always equals 0x43 */
109 	u8	control;	/* settings of flow control lines */
110 #define CONTROL_MASK		0x0c
111 #define CONTROL_DTR_HIGH	0x08
112 #define CONTROL_RTS_HIGH	0x04
113 	u8	tx_status;
114 #define	TX_BUFFER_EMPTIED	0x09
115 	u8	pin_state;
116 #define PIN_MASK		0x3f
117 #define PIN_RTS			0x20	/* output pin */
118 #define PIN_CTS			0x10	/* input pin, active low */
119 #define PIN_DSR			0x08	/* input pin, active low */
120 #define PIN_DTR			0x04	/* output pin */
121 #define PIN_RI			0x02	/* input pin, active low */
122 #define PIN_DCD			0x01	/* input pin, active low */
123 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
124 };
125 
126 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
127 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
128 	(((a)->divisor == (priv)->pending_setup.divisor) \
129 	  && ((a)->control == (priv)->pending_setup.control) \
130 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt))
131 
132 /* function prototypes */
133 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port);
134 static void oti6858_close(struct usb_serial_port *port);
135 static void oti6858_set_termios(struct tty_struct *tty,
136 			struct usb_serial_port *port, struct ktermios *old);
137 static void oti6858_init_termios(struct tty_struct *tty);
138 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
139 			unsigned int cmd, unsigned long arg);
140 static void oti6858_read_int_callback(struct urb *urb);
141 static void oti6858_read_bulk_callback(struct urb *urb);
142 static void oti6858_write_bulk_callback(struct urb *urb);
143 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
144 			const unsigned char *buf, int count);
145 static int oti6858_write_room(struct tty_struct *tty);
146 static int oti6858_chars_in_buffer(struct tty_struct *tty);
147 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file);
148 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
149 				unsigned int set, unsigned int clear);
150 static int oti6858_startup(struct usb_serial *serial);
151 static void oti6858_release(struct usb_serial *serial);
152 
153 /* device info */
154 static struct usb_serial_driver oti6858_device = {
155 	.driver = {
156 		.owner =	THIS_MODULE,
157 		.name =		"oti6858",
158 	},
159 	.id_table =		id_table,
160 	.num_ports =		1,
161 	.open =			oti6858_open,
162 	.close =		oti6858_close,
163 	.write =		oti6858_write,
164 	.ioctl =		oti6858_ioctl,
165 	.set_termios =		oti6858_set_termios,
166 	.init_termios = 	oti6858_init_termios,
167 	.tiocmget =		oti6858_tiocmget,
168 	.tiocmset =		oti6858_tiocmset,
169 	.read_bulk_callback =	oti6858_read_bulk_callback,
170 	.read_int_callback =	oti6858_read_int_callback,
171 	.write_bulk_callback =	oti6858_write_bulk_callback,
172 	.write_room =		oti6858_write_room,
173 	.chars_in_buffer =	oti6858_chars_in_buffer,
174 	.attach =		oti6858_startup,
175 	.release =		oti6858_release,
176 };
177 
178 struct oti6858_private {
179 	spinlock_t lock;
180 
181 	struct oti6858_control_pkt status;
182 
183 	struct {
184 		u8 read_urb_in_use;
185 		u8 write_urb_in_use;
186 	} flags;
187 	struct delayed_work delayed_write_work;
188 
189 	struct {
190 		__le16 divisor;
191 		u8 frame_fmt;
192 		u8 control;
193 	} pending_setup;
194 	u8 transient;
195 	u8 setup_done;
196 	struct delayed_work delayed_setup_work;
197 
198 	wait_queue_head_t intr_wait;
199 	struct usb_serial_port *port;   /* USB port with which associated */
200 };
201 
202 static void setup_line(struct work_struct *work)
203 {
204 	struct oti6858_private *priv = container_of(work,
205 			struct oti6858_private, delayed_setup_work.work);
206 	struct usb_serial_port *port = priv->port;
207 	struct oti6858_control_pkt *new_setup;
208 	unsigned long flags;
209 	int result;
210 
211 	dbg("%s(port = %d)", __func__, port->number);
212 
213 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
214 	if (new_setup == NULL) {
215 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
216 		/* we will try again */
217 		schedule_delayed_work(&priv->delayed_setup_work,
218 						msecs_to_jiffies(2));
219 		return;
220 	}
221 
222 	result = usb_control_msg(port->serial->dev,
223 				usb_rcvctrlpipe(port->serial->dev, 0),
224 				OTI6858_REQ_T_GET_STATUS,
225 				OTI6858_REQ_GET_STATUS,
226 				0, 0,
227 				new_setup, OTI6858_CTRL_PKT_SIZE,
228 				100);
229 
230 	if (result != OTI6858_CTRL_PKT_SIZE) {
231 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
232 		kfree(new_setup);
233 		/* we will try again */
234 		schedule_delayed_work(&priv->delayed_setup_work,
235 							msecs_to_jiffies(2));
236 		return;
237 	}
238 
239 	spin_lock_irqsave(&priv->lock, flags);
240 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
241 		new_setup->divisor = priv->pending_setup.divisor;
242 		new_setup->control = priv->pending_setup.control;
243 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
244 
245 		spin_unlock_irqrestore(&priv->lock, flags);
246 		result = usb_control_msg(port->serial->dev,
247 					usb_sndctrlpipe(port->serial->dev, 0),
248 					OTI6858_REQ_T_SET_LINE,
249 					OTI6858_REQ_SET_LINE,
250 					0, 0,
251 					new_setup, OTI6858_CTRL_PKT_SIZE,
252 					100);
253 	} else {
254 		spin_unlock_irqrestore(&priv->lock, flags);
255 		result = 0;
256 	}
257 	kfree(new_setup);
258 
259 	spin_lock_irqsave(&priv->lock, flags);
260 	if (result != OTI6858_CTRL_PKT_SIZE)
261 		priv->transient = 0;
262 	priv->setup_done = 1;
263 	spin_unlock_irqrestore(&priv->lock, flags);
264 
265 	dbg("%s(): submitting interrupt urb", __func__);
266 	port->interrupt_in_urb->dev = port->serial->dev;
267 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
268 	if (result != 0) {
269 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
270 				" with error %d\n", __func__, result);
271 	}
272 }
273 
274 static void send_data(struct work_struct *work)
275 {
276 	struct oti6858_private *priv = container_of(work,
277 			struct oti6858_private, delayed_write_work.work);
278 	struct usb_serial_port *port = priv->port;
279 	int count = 0, result;
280 	unsigned long flags;
281 	u8 *allow;
282 
283 	dbg("%s(port = %d)", __func__, port->number);
284 
285 	spin_lock_irqsave(&priv->lock, flags);
286 	if (priv->flags.write_urb_in_use) {
287 		spin_unlock_irqrestore(&priv->lock, flags);
288 		schedule_delayed_work(&priv->delayed_write_work,
289 						msecs_to_jiffies(2));
290 		return;
291 	}
292 	priv->flags.write_urb_in_use = 1;
293 	spin_unlock_irqrestore(&priv->lock, flags);
294 
295 	spin_lock_irqsave(&port->lock, flags);
296 	count = kfifo_len(&port->write_fifo);
297 	spin_unlock_irqrestore(&port->lock, flags);
298 
299 	if (count > port->bulk_out_size)
300 		count = port->bulk_out_size;
301 
302 	if (count != 0) {
303 		allow = kmalloc(1, GFP_KERNEL);
304 		if (!allow) {
305 			dev_err(&port->dev, "%s(): kmalloc failed\n",
306 					__func__);
307 			return;
308 		}
309 		result = usb_control_msg(port->serial->dev,
310 				usb_rcvctrlpipe(port->serial->dev, 0),
311 				OTI6858_REQ_T_CHECK_TXBUFF,
312 				OTI6858_REQ_CHECK_TXBUFF,
313 				count, 0, allow, 1, 100);
314 		if (result != 1 || *allow != 0)
315 			count = 0;
316 		kfree(allow);
317 	}
318 
319 	if (count == 0) {
320 		priv->flags.write_urb_in_use = 0;
321 
322 		dbg("%s(): submitting interrupt urb", __func__);
323 		port->interrupt_in_urb->dev = port->serial->dev;
324 		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
325 		if (result != 0) {
326 			dev_err(&port->dev, "%s(): usb_submit_urb() failed"
327 				" with error %d\n", __func__, result);
328 		}
329 		return;
330 	}
331 
332 	count = kfifo_out_locked(&port->write_fifo,
333 					port->write_urb->transfer_buffer,
334 					count, &port->lock);
335 	port->write_urb->transfer_buffer_length = count;
336 	port->write_urb->dev = port->serial->dev;
337 	result = usb_submit_urb(port->write_urb, GFP_NOIO);
338 	if (result != 0) {
339 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
340 			       " with error %d\n", __func__, result);
341 		priv->flags.write_urb_in_use = 0;
342 	}
343 
344 	usb_serial_port_softint(port);
345 }
346 
347 static int oti6858_startup(struct usb_serial *serial)
348 {
349 	struct usb_serial_port *port = serial->port[0];
350 	struct oti6858_private *priv;
351 	int i;
352 
353 	for (i = 0; i < serial->num_ports; ++i) {
354 		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
355 		if (!priv)
356 			break;
357 
358 		spin_lock_init(&priv->lock);
359 		init_waitqueue_head(&priv->intr_wait);
360 /*		INIT_WORK(&priv->setup_work, setup_line, serial->port[i]); */
361 /*		INIT_WORK(&priv->write_work, send_data, serial->port[i]); */
362 		priv->port = port;
363 		INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
364 		INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
365 
366 		usb_set_serial_port_data(serial->port[i], priv);
367 	}
368 	if (i == serial->num_ports)
369 		return 0;
370 
371 	for (--i; i >= 0; --i) {
372 		priv = usb_get_serial_port_data(serial->port[i]);
373 		kfree(priv);
374 		usb_set_serial_port_data(serial->port[i], NULL);
375 	}
376 	return -ENOMEM;
377 }
378 
379 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
380 			const unsigned char *buf, int count)
381 {
382 	dbg("%s(port = %d, count = %d)", __func__, port->number, count);
383 
384 	if (!count)
385 		return count;
386 
387 	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
388 
389 	return count;
390 }
391 
392 static int oti6858_write_room(struct tty_struct *tty)
393 {
394 	struct usb_serial_port *port = tty->driver_data;
395 	int room = 0;
396 	unsigned long flags;
397 
398 	dbg("%s(port = %d)", __func__, port->number);
399 
400 	spin_lock_irqsave(&port->lock, flags);
401 	room = kfifo_avail(&port->write_fifo);
402 	spin_unlock_irqrestore(&port->lock, flags);
403 
404 	return room;
405 }
406 
407 static int oti6858_chars_in_buffer(struct tty_struct *tty)
408 {
409 	struct usb_serial_port *port = tty->driver_data;
410 	int chars = 0;
411 	unsigned long flags;
412 
413 	dbg("%s(port = %d)", __func__, port->number);
414 
415 	spin_lock_irqsave(&port->lock, flags);
416 	chars = kfifo_len(&port->write_fifo);
417 	spin_unlock_irqrestore(&port->lock, flags);
418 
419 	return chars;
420 }
421 
422 static void oti6858_init_termios(struct tty_struct *tty)
423 {
424 	*(tty->termios) = tty_std_termios;
425 	tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
426 	tty->termios->c_ispeed = 38400;
427 	tty->termios->c_ospeed = 38400;
428 }
429 
430 static void oti6858_set_termios(struct tty_struct *tty,
431 		struct usb_serial_port *port, struct ktermios *old_termios)
432 {
433 	struct oti6858_private *priv = usb_get_serial_port_data(port);
434 	unsigned long flags;
435 	unsigned int cflag;
436 	u8 frame_fmt, control;
437 	__le16 divisor;
438 	int br;
439 
440 	dbg("%s(port = %d)", __func__, port->number);
441 
442 	if (!tty) {
443 		dbg("%s(): no tty structures", __func__);
444 		return;
445 	}
446 
447 	cflag = tty->termios->c_cflag;
448 
449 	spin_lock_irqsave(&priv->lock, flags);
450 	divisor = priv->pending_setup.divisor;
451 	frame_fmt = priv->pending_setup.frame_fmt;
452 	control = priv->pending_setup.control;
453 	spin_unlock_irqrestore(&priv->lock, flags);
454 
455 	frame_fmt &= ~FMT_DATA_BITS_MASK;
456 	switch (cflag & CSIZE) {
457 	case CS5:
458 		frame_fmt |= FMT_DATA_BITS_5;
459 		break;
460 	case CS6:
461 		frame_fmt |= FMT_DATA_BITS_6;
462 		break;
463 	case CS7:
464 		frame_fmt |= FMT_DATA_BITS_7;
465 		break;
466 	default:
467 	case CS8:
468 		frame_fmt |= FMT_DATA_BITS_8;
469 		break;
470 	}
471 
472 	/* manufacturer claims that this device can work with baud rates
473 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
474 	 * guarantee that any other baud rate will work (especially
475 	 * the higher ones)
476 	 */
477 	br = tty_get_baud_rate(tty);
478 	if (br == 0) {
479 		divisor = 0;
480 	} else {
481 		int real_br;
482 		int new_divisor;
483 		br = min(br, OTI6858_MAX_BAUD_RATE);
484 
485 		new_divisor = (96000000 + 8 * br) / (16 * br);
486 		real_br = 96000000 / (16 * new_divisor);
487 		divisor = cpu_to_le16(new_divisor);
488 		tty_encode_baud_rate(tty, real_br, real_br);
489 	}
490 
491 	frame_fmt &= ~FMT_STOP_BITS_MASK;
492 	if ((cflag & CSTOPB) != 0)
493 		frame_fmt |= FMT_STOP_BITS_2;
494 	else
495 		frame_fmt |= FMT_STOP_BITS_1;
496 
497 	frame_fmt &= ~FMT_PARITY_MASK;
498 	if ((cflag & PARENB) != 0) {
499 		if ((cflag & PARODD) != 0)
500 			frame_fmt |= FMT_PARITY_ODD;
501 		else
502 			frame_fmt |= FMT_PARITY_EVEN;
503 	} else {
504 		frame_fmt |= FMT_PARITY_NONE;
505 	}
506 
507 	control &= ~CONTROL_MASK;
508 	if ((cflag & CRTSCTS) != 0)
509 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
510 
511 	/* change control lines if we are switching to or from B0 */
512 	/* FIXME:
513 	spin_lock_irqsave(&priv->lock, flags);
514 	control = priv->line_control;
515 	if ((cflag & CBAUD) == B0)
516 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
517 	else
518 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
519 	if (control != priv->line_control) {
520 		control = priv->line_control;
521 		spin_unlock_irqrestore(&priv->lock, flags);
522 		set_control_lines(serial->dev, control);
523 	} else {
524 		spin_unlock_irqrestore(&priv->lock, flags);
525 	}
526 	*/
527 
528 	spin_lock_irqsave(&priv->lock, flags);
529 	if (divisor != priv->pending_setup.divisor
530 			|| control != priv->pending_setup.control
531 			|| frame_fmt != priv->pending_setup.frame_fmt) {
532 		priv->pending_setup.divisor = divisor;
533 		priv->pending_setup.control = control;
534 		priv->pending_setup.frame_fmt = frame_fmt;
535 	}
536 	spin_unlock_irqrestore(&priv->lock, flags);
537 }
538 
539 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
540 {
541 	struct oti6858_private *priv = usb_get_serial_port_data(port);
542 	struct ktermios tmp_termios;
543 	struct usb_serial *serial = port->serial;
544 	struct oti6858_control_pkt *buf;
545 	unsigned long flags;
546 	int result;
547 
548 	dbg("%s(port = %d)", __func__, port->number);
549 
550 	usb_clear_halt(serial->dev, port->write_urb->pipe);
551 	usb_clear_halt(serial->dev, port->read_urb->pipe);
552 
553 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
554 	if (buf == NULL) {
555 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
556 		return -ENOMEM;
557 	}
558 
559 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
560 				OTI6858_REQ_T_GET_STATUS,
561 				OTI6858_REQ_GET_STATUS,
562 				0, 0,
563 				buf, OTI6858_CTRL_PKT_SIZE,
564 				100);
565 	if (result != OTI6858_CTRL_PKT_SIZE) {
566 		/* assume default (after power-on reset) values */
567 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
568 		buf->frame_fmt = 0x03;	/* 8N1 */
569 		buf->something = 0x43;
570 		buf->control = 0x4c;	/* DTR, RTS */
571 		buf->tx_status = 0x00;
572 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
573 		buf->rx_bytes_avail = 0x00;
574 	}
575 
576 	spin_lock_irqsave(&priv->lock, flags);
577 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
578 	priv->pending_setup.divisor = buf->divisor;
579 	priv->pending_setup.frame_fmt = buf->frame_fmt;
580 	priv->pending_setup.control = buf->control;
581 	spin_unlock_irqrestore(&priv->lock, flags);
582 	kfree(buf);
583 
584 	dbg("%s(): submitting interrupt urb", __func__);
585 	port->interrupt_in_urb->dev = serial->dev;
586 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
587 	if (result != 0) {
588 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
589 			       " with error %d\n", __func__, result);
590 		oti6858_close(port);
591 		return -EPROTO;
592 	}
593 
594 	/* setup termios */
595 	if (tty)
596 		oti6858_set_termios(tty, port, &tmp_termios);
597 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
598 	return 0;
599 }
600 
601 static void oti6858_close(struct usb_serial_port *port)
602 {
603 	struct oti6858_private *priv = usb_get_serial_port_data(port);
604 	unsigned long flags;
605 
606 	dbg("%s(port = %d)", __func__, port->number);
607 
608 	spin_lock_irqsave(&port->lock, flags);
609 	/* clear out any remaining data in the buffer */
610 	kfifo_reset_out(&port->write_fifo);
611 	spin_unlock_irqrestore(&port->lock, flags);
612 
613 	dbg("%s(): after buf_clear()", __func__);
614 
615 	/* cancel scheduled setup */
616 	cancel_delayed_work(&priv->delayed_setup_work);
617 	cancel_delayed_work(&priv->delayed_write_work);
618 	flush_scheduled_work();
619 
620 	/* shutdown our urbs */
621 	dbg("%s(): shutting down urbs", __func__);
622 	usb_kill_urb(port->write_urb);
623 	usb_kill_urb(port->read_urb);
624 	usb_kill_urb(port->interrupt_in_urb);
625 }
626 
627 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
628 				unsigned int set, unsigned int clear)
629 {
630 	struct usb_serial_port *port = tty->driver_data;
631 	struct oti6858_private *priv = usb_get_serial_port_data(port);
632 	unsigned long flags;
633 	u8 control;
634 
635 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
636 				__func__, port->number, set, clear);
637 
638 	if (!usb_get_intfdata(port->serial->interface))
639 		return -ENODEV;
640 
641 	/* FIXME: check if this is correct (active high/low) */
642 	spin_lock_irqsave(&priv->lock, flags);
643 	control = priv->pending_setup.control;
644 	if ((set & TIOCM_RTS) != 0)
645 		control |= CONTROL_RTS_HIGH;
646 	if ((set & TIOCM_DTR) != 0)
647 		control |= CONTROL_DTR_HIGH;
648 	if ((clear & TIOCM_RTS) != 0)
649 		control &= ~CONTROL_RTS_HIGH;
650 	if ((clear & TIOCM_DTR) != 0)
651 		control &= ~CONTROL_DTR_HIGH;
652 
653 	if (control != priv->pending_setup.control)
654 		priv->pending_setup.control = control;
655 
656 	spin_unlock_irqrestore(&priv->lock, flags);
657 	return 0;
658 }
659 
660 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file)
661 {
662 	struct usb_serial_port *port = tty->driver_data;
663 	struct oti6858_private *priv = usb_get_serial_port_data(port);
664 	unsigned long flags;
665 	unsigned pin_state;
666 	unsigned result = 0;
667 
668 	dbg("%s(port = %d)", __func__, port->number);
669 
670 	if (!usb_get_intfdata(port->serial->interface))
671 		return -ENODEV;
672 
673 	spin_lock_irqsave(&priv->lock, flags);
674 	pin_state = priv->status.pin_state & PIN_MASK;
675 	spin_unlock_irqrestore(&priv->lock, flags);
676 
677 	/* FIXME: check if this is correct (active high/low) */
678 	if ((pin_state & PIN_RTS) != 0)
679 		result |= TIOCM_RTS;
680 	if ((pin_state & PIN_CTS) != 0)
681 		result |= TIOCM_CTS;
682 	if ((pin_state & PIN_DSR) != 0)
683 		result |= TIOCM_DSR;
684 	if ((pin_state & PIN_DTR) != 0)
685 		result |= TIOCM_DTR;
686 	if ((pin_state & PIN_RI) != 0)
687 		result |= TIOCM_RI;
688 	if ((pin_state & PIN_DCD) != 0)
689 		result |= TIOCM_CD;
690 
691 	dbg("%s() = 0x%08x", __func__, result);
692 
693 	return result;
694 }
695 
696 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
697 {
698 	struct oti6858_private *priv = usb_get_serial_port_data(port);
699 	unsigned long flags;
700 	unsigned int prev, status;
701 	unsigned int changed;
702 
703 	spin_lock_irqsave(&priv->lock, flags);
704 	prev = priv->status.pin_state;
705 	spin_unlock_irqrestore(&priv->lock, flags);
706 
707 	while (1) {
708 		wait_event_interruptible(priv->intr_wait,
709 					priv->status.pin_state != prev);
710 		if (signal_pending(current))
711 			return -ERESTARTSYS;
712 
713 		spin_lock_irqsave(&priv->lock, flags);
714 		status = priv->status.pin_state & PIN_MASK;
715 		spin_unlock_irqrestore(&priv->lock, flags);
716 
717 		changed = prev ^ status;
718 		/* FIXME: check if this is correct (active high/low) */
719 		if (((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
720 		    ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
721 		    ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
722 		    ((arg & TIOCM_CTS) && (changed & PIN_CTS)))
723 			return 0;
724 		prev = status;
725 	}
726 
727 	/* NOTREACHED */
728 	return 0;
729 }
730 
731 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
732 			unsigned int cmd, unsigned long arg)
733 {
734 	struct usb_serial_port *port = tty->driver_data;
735 
736 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
737 				__func__, port->number, cmd, arg);
738 
739 	switch (cmd) {
740 	case TIOCMIWAIT:
741 		dbg("%s(): TIOCMIWAIT", __func__);
742 		return wait_modem_info(port, arg);
743 	default:
744 		dbg("%s(): 0x%04x not supported", __func__, cmd);
745 		break;
746 	}
747 	return -ENOIOCTLCMD;
748 }
749 
750 
751 static void oti6858_release(struct usb_serial *serial)
752 {
753 	int i;
754 
755 	dbg("%s()", __func__);
756 
757 	for (i = 0; i < serial->num_ports; ++i)
758 		kfree(usb_get_serial_port_data(serial->port[i]));
759 }
760 
761 static void oti6858_read_int_callback(struct urb *urb)
762 {
763 	struct usb_serial_port *port =  urb->context;
764 	struct oti6858_private *priv = usb_get_serial_port_data(port);
765 	int transient = 0, can_recv = 0, resubmit = 1;
766 	int status = urb->status;
767 
768 	dbg("%s(port = %d, status = %d)",
769 				__func__, port->number, status);
770 
771 	switch (status) {
772 	case 0:
773 		/* success */
774 		break;
775 	case -ECONNRESET:
776 	case -ENOENT:
777 	case -ESHUTDOWN:
778 		/* this urb is terminated, clean up */
779 		dbg("%s(): urb shutting down with status: %d",
780 					__func__, status);
781 		return;
782 	default:
783 		dbg("%s(): nonzero urb status received: %d",
784 					__func__, status);
785 		break;
786 	}
787 
788 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
789 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
790 		unsigned long flags;
791 
792 		spin_lock_irqsave(&priv->lock, flags);
793 
794 		if (!priv->transient) {
795 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
796 				if (xs->rx_bytes_avail == 0) {
797 					priv->transient = 4;
798 					priv->setup_done = 0;
799 					resubmit = 0;
800 					dbg("%s(): scheduling setup_line()",
801 					    __func__);
802 					schedule_delayed_work(&priv->delayed_setup_work, 0);
803 				}
804 			}
805 		} else {
806 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
807 				priv->transient = 0;
808 			} else if (!priv->setup_done) {
809 				resubmit = 0;
810 			} else if (--priv->transient == 0) {
811 				if (xs->rx_bytes_avail == 0) {
812 					priv->transient = 4;
813 					priv->setup_done = 0;
814 					resubmit = 0;
815 					dbg("%s(): scheduling setup_line()",
816 					    __func__);
817 					schedule_delayed_work(&priv->delayed_setup_work, 0);
818 				}
819 			}
820 		}
821 
822 		if (!priv->transient) {
823 			if (xs->pin_state != priv->status.pin_state)
824 				wake_up_interruptible(&priv->intr_wait);
825 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
826 		}
827 
828 		if (!priv->transient && xs->rx_bytes_avail != 0) {
829 			can_recv = xs->rx_bytes_avail;
830 			priv->flags.read_urb_in_use = 1;
831 		}
832 
833 		transient = priv->transient;
834 		spin_unlock_irqrestore(&priv->lock, flags);
835 	}
836 
837 	if (can_recv) {
838 		int result;
839 
840 		port->read_urb->dev = port->serial->dev;
841 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
842 		if (result != 0) {
843 			priv->flags.read_urb_in_use = 0;
844 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
845 					" error %d\n", __func__, result);
846 		} else {
847 			resubmit = 0;
848 		}
849 	} else if (!transient) {
850 		unsigned long flags;
851 		int count;
852 
853 		spin_lock_irqsave(&port->lock, flags);
854 		count = kfifo_len(&port->write_fifo);
855 		spin_unlock_irqrestore(&port->lock, flags);
856 
857 		spin_lock_irqsave(&priv->lock, flags);
858 		if (priv->flags.write_urb_in_use == 0 && count != 0) {
859 			schedule_delayed_work(&priv->delayed_write_work, 0);
860 			resubmit = 0;
861 		}
862 		spin_unlock_irqrestore(&priv->lock, flags);
863 	}
864 
865 	if (resubmit) {
866 		int result;
867 
868 /*		dbg("%s(): submitting interrupt urb", __func__); */
869 		urb->dev = port->serial->dev;
870 		result = usb_submit_urb(urb, GFP_ATOMIC);
871 		if (result != 0) {
872 			dev_err(&urb->dev->dev,
873 					"%s(): usb_submit_urb() failed with"
874 					" error %d\n", __func__, result);
875 		}
876 	}
877 }
878 
879 static void oti6858_read_bulk_callback(struct urb *urb)
880 {
881 	struct usb_serial_port *port =  urb->context;
882 	struct oti6858_private *priv = usb_get_serial_port_data(port);
883 	struct tty_struct *tty;
884 	unsigned char *data = urb->transfer_buffer;
885 	unsigned long flags;
886 	int status = urb->status;
887 	int result;
888 
889 	dbg("%s(port = %d, status = %d)",
890 				__func__, port->number, status);
891 
892 	spin_lock_irqsave(&priv->lock, flags);
893 	priv->flags.read_urb_in_use = 0;
894 	spin_unlock_irqrestore(&priv->lock, flags);
895 
896 	if (status != 0) {
897 		/*
898 		if (status == -EPROTO) {
899 			* PL2303 mysteriously fails with -EPROTO reschedule
900 			   the read *
901 			dbg("%s - caught -EPROTO, resubmitting the urb",
902 								__func__);
903 			result = usb_submit_urb(urb, GFP_ATOMIC);
904 			if (result)
905 				dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __func__, result);
906 			return;
907 		}
908 		*/
909 		dbg("%s(): unable to handle the error, exiting", __func__);
910 		return;
911 	}
912 
913 	tty = tty_port_tty_get(&port->port);
914 	if (tty != NULL && urb->actual_length > 0) {
915 		tty_insert_flip_string(tty, data, urb->actual_length);
916 		tty_flip_buffer_push(tty);
917 	}
918 	tty_kref_put(tty);
919 
920 	/* schedule the interrupt urb */
921 	port->interrupt_in_urb->dev = port->serial->dev;
922 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
923 	if (result != 0 && result != -EPERM) {
924 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
925 				" error %d\n", __func__, result);
926 	}
927 }
928 
929 static void oti6858_write_bulk_callback(struct urb *urb)
930 {
931 	struct usb_serial_port *port =  urb->context;
932 	struct oti6858_private *priv = usb_get_serial_port_data(port);
933 	int status = urb->status;
934 	int result;
935 
936 	dbg("%s(port = %d, status = %d)",
937 				__func__, port->number, status);
938 
939 	switch (status) {
940 	case 0:
941 		/* success */
942 		break;
943 	case -ECONNRESET:
944 	case -ENOENT:
945 	case -ESHUTDOWN:
946 		/* this urb is terminated, clean up */
947 		dbg("%s(): urb shutting down with status: %d",
948 					__func__, status);
949 		priv->flags.write_urb_in_use = 0;
950 		return;
951 	default:
952 		/* error in the urb, so we have to resubmit it */
953 		dbg("%s(): nonzero write bulk status received: %d",
954 					__func__, status);
955 		dbg("%s(): overflow in write", __func__);
956 
957 		port->write_urb->transfer_buffer_length = 1;
958 		port->write_urb->dev = port->serial->dev;
959 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
960 		if (result) {
961 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
962 					" error %d\n", __func__, result);
963 		} else {
964 			return;
965 		}
966 	}
967 
968 	priv->flags.write_urb_in_use = 0;
969 
970 	/* schedule the interrupt urb if we are still open */
971 	port->interrupt_in_urb->dev = port->serial->dev;
972 	dbg("%s(): submitting interrupt urb", __func__);
973 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
974 	if (result != 0) {
975 		dev_err(&port->dev, "%s(): failed submitting int urb,"
976 					" error %d\n", __func__, result);
977 	}
978 }
979 
980 /* module description and (de)initialization */
981 
982 static int __init oti6858_init(void)
983 {
984 	int retval;
985 
986 	retval = usb_serial_register(&oti6858_device);
987 	if (retval == 0) {
988 		retval = usb_register(&oti6858_driver);
989 		if (retval)
990 			usb_serial_deregister(&oti6858_device);
991 	}
992 	return retval;
993 }
994 
995 static void __exit oti6858_exit(void)
996 {
997 	usb_deregister(&oti6858_driver);
998 	usb_serial_deregister(&oti6858_device);
999 }
1000 
1001 module_init(oti6858_init);
1002 module_exit(oti6858_exit);
1003 
1004 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1005 MODULE_AUTHOR(OTI6858_AUTHOR);
1006 MODULE_VERSION(OTI6858_VERSION);
1007 MODULE_LICENSE("GPL");
1008 
1009 module_param(debug, bool, S_IRUGO | S_IWUSR);
1010 MODULE_PARM_DESC(debug, "enable debug output");
1011 
1012