xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision 32078f915d1acab356080b144aa89fe3487f3979)
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 	.id_table =	id_table,
72 };
73 
74 static bool debug;
75 
76 /* requests */
77 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
78 #define	OTI6858_REQ_T_GET_STATUS	0x01
79 
80 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
81 #define	OTI6858_REQ_T_SET_LINE		0x00
82 
83 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
84 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
85 
86 /* format of the control packet */
87 struct oti6858_control_pkt {
88 	__le16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
89 #define OTI6858_MAX_BAUD_RATE	3000000
90 	u8	frame_fmt;
91 #define FMT_STOP_BITS_MASK	0xc0
92 #define FMT_STOP_BITS_1		0x00
93 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
94 #define FMT_PARITY_MASK		0x38
95 #define FMT_PARITY_NONE		0x00
96 #define FMT_PARITY_ODD		0x08
97 #define FMT_PARITY_EVEN		0x18
98 #define FMT_PARITY_MARK		0x28
99 #define FMT_PARITY_SPACE	0x38
100 #define FMT_DATA_BITS_MASK	0x03
101 #define FMT_DATA_BITS_5		0x00
102 #define FMT_DATA_BITS_6		0x01
103 #define FMT_DATA_BITS_7		0x02
104 #define FMT_DATA_BITS_8		0x03
105 	u8	something;	/* always equals 0x43 */
106 	u8	control;	/* settings of flow control lines */
107 #define CONTROL_MASK		0x0c
108 #define CONTROL_DTR_HIGH	0x08
109 #define CONTROL_RTS_HIGH	0x04
110 	u8	tx_status;
111 #define	TX_BUFFER_EMPTIED	0x09
112 	u8	pin_state;
113 #define PIN_MASK		0x3f
114 #define PIN_RTS			0x20	/* output pin */
115 #define PIN_CTS			0x10	/* input pin, active low */
116 #define PIN_DSR			0x08	/* input pin, active low */
117 #define PIN_DTR			0x04	/* output pin */
118 #define PIN_RI			0x02	/* input pin, active low */
119 #define PIN_DCD			0x01	/* input pin, active low */
120 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
121 };
122 
123 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
124 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
125 	(((a)->divisor == (priv)->pending_setup.divisor) \
126 	  && ((a)->control == (priv)->pending_setup.control) \
127 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt))
128 
129 /* function prototypes */
130 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port);
131 static void oti6858_close(struct usb_serial_port *port);
132 static void oti6858_set_termios(struct tty_struct *tty,
133 			struct usb_serial_port *port, struct ktermios *old);
134 static void oti6858_init_termios(struct tty_struct *tty);
135 static int oti6858_ioctl(struct tty_struct *tty,
136 			unsigned int cmd, unsigned long arg);
137 static void oti6858_read_int_callback(struct urb *urb);
138 static void oti6858_read_bulk_callback(struct urb *urb);
139 static void oti6858_write_bulk_callback(struct urb *urb);
140 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
141 			const unsigned char *buf, int count);
142 static int oti6858_write_room(struct tty_struct *tty);
143 static int oti6858_chars_in_buffer(struct tty_struct *tty);
144 static int oti6858_tiocmget(struct tty_struct *tty);
145 static int oti6858_tiocmset(struct tty_struct *tty,
146 				unsigned int set, unsigned int clear);
147 static int oti6858_startup(struct usb_serial *serial);
148 static void oti6858_release(struct usb_serial *serial);
149 
150 /* device info */
151 static struct usb_serial_driver oti6858_device = {
152 	.driver = {
153 		.owner =	THIS_MODULE,
154 		.name =		"oti6858",
155 	},
156 	.id_table =		id_table,
157 	.num_ports =		1,
158 	.open =			oti6858_open,
159 	.close =		oti6858_close,
160 	.write =		oti6858_write,
161 	.ioctl =		oti6858_ioctl,
162 	.set_termios =		oti6858_set_termios,
163 	.init_termios = 	oti6858_init_termios,
164 	.tiocmget =		oti6858_tiocmget,
165 	.tiocmset =		oti6858_tiocmset,
166 	.read_bulk_callback =	oti6858_read_bulk_callback,
167 	.read_int_callback =	oti6858_read_int_callback,
168 	.write_bulk_callback =	oti6858_write_bulk_callback,
169 	.write_room =		oti6858_write_room,
170 	.chars_in_buffer =	oti6858_chars_in_buffer,
171 	.attach =		oti6858_startup,
172 	.release =		oti6858_release,
173 };
174 
175 static struct usb_serial_driver * const serial_drivers[] = {
176 	&oti6858_device, NULL
177 };
178 
179 struct oti6858_private {
180 	spinlock_t lock;
181 
182 	struct oti6858_control_pkt status;
183 
184 	struct {
185 		u8 read_urb_in_use;
186 		u8 write_urb_in_use;
187 	} flags;
188 	struct delayed_work delayed_write_work;
189 
190 	struct {
191 		__le16 divisor;
192 		u8 frame_fmt;
193 		u8 control;
194 	} pending_setup;
195 	u8 transient;
196 	u8 setup_done;
197 	struct delayed_work delayed_setup_work;
198 
199 	wait_queue_head_t intr_wait;
200 	struct usb_serial_port *port;   /* USB port with which associated */
201 };
202 
203 static void setup_line(struct work_struct *work)
204 {
205 	struct oti6858_private *priv = container_of(work,
206 			struct oti6858_private, delayed_setup_work.work);
207 	struct usb_serial_port *port = priv->port;
208 	struct oti6858_control_pkt *new_setup;
209 	unsigned long flags;
210 	int result;
211 
212 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
213 	if (new_setup == NULL) {
214 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
215 		/* we will try again */
216 		schedule_delayed_work(&priv->delayed_setup_work,
217 						msecs_to_jiffies(2));
218 		return;
219 	}
220 
221 	result = usb_control_msg(port->serial->dev,
222 				usb_rcvctrlpipe(port->serial->dev, 0),
223 				OTI6858_REQ_T_GET_STATUS,
224 				OTI6858_REQ_GET_STATUS,
225 				0, 0,
226 				new_setup, OTI6858_CTRL_PKT_SIZE,
227 				100);
228 
229 	if (result != OTI6858_CTRL_PKT_SIZE) {
230 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
231 		kfree(new_setup);
232 		/* we will try again */
233 		schedule_delayed_work(&priv->delayed_setup_work,
234 							msecs_to_jiffies(2));
235 		return;
236 	}
237 
238 	spin_lock_irqsave(&priv->lock, flags);
239 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
240 		new_setup->divisor = priv->pending_setup.divisor;
241 		new_setup->control = priv->pending_setup.control;
242 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
243 
244 		spin_unlock_irqrestore(&priv->lock, flags);
245 		result = usb_control_msg(port->serial->dev,
246 					usb_sndctrlpipe(port->serial->dev, 0),
247 					OTI6858_REQ_T_SET_LINE,
248 					OTI6858_REQ_SET_LINE,
249 					0, 0,
250 					new_setup, OTI6858_CTRL_PKT_SIZE,
251 					100);
252 	} else {
253 		spin_unlock_irqrestore(&priv->lock, flags);
254 		result = 0;
255 	}
256 	kfree(new_setup);
257 
258 	spin_lock_irqsave(&priv->lock, flags);
259 	if (result != OTI6858_CTRL_PKT_SIZE)
260 		priv->transient = 0;
261 	priv->setup_done = 1;
262 	spin_unlock_irqrestore(&priv->lock, flags);
263 
264 	dbg("%s(): submitting interrupt urb", __func__);
265 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
266 	if (result != 0) {
267 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
268 				" with error %d\n", __func__, result);
269 	}
270 }
271 
272 static void send_data(struct work_struct *work)
273 {
274 	struct oti6858_private *priv = container_of(work,
275 			struct oti6858_private, delayed_write_work.work);
276 	struct usb_serial_port *port = priv->port;
277 	int count = 0, result;
278 	unsigned long flags;
279 	u8 *allow;
280 
281 	spin_lock_irqsave(&priv->lock, flags);
282 	if (priv->flags.write_urb_in_use) {
283 		spin_unlock_irqrestore(&priv->lock, flags);
284 		schedule_delayed_work(&priv->delayed_write_work,
285 						msecs_to_jiffies(2));
286 		return;
287 	}
288 	priv->flags.write_urb_in_use = 1;
289 	spin_unlock_irqrestore(&priv->lock, flags);
290 
291 	spin_lock_irqsave(&port->lock, flags);
292 	count = kfifo_len(&port->write_fifo);
293 	spin_unlock_irqrestore(&port->lock, flags);
294 
295 	if (count > port->bulk_out_size)
296 		count = port->bulk_out_size;
297 
298 	if (count != 0) {
299 		allow = kmalloc(1, GFP_KERNEL);
300 		if (!allow) {
301 			dev_err_console(port, "%s(): kmalloc failed\n",
302 					__func__);
303 			return;
304 		}
305 		result = usb_control_msg(port->serial->dev,
306 				usb_rcvctrlpipe(port->serial->dev, 0),
307 				OTI6858_REQ_T_CHECK_TXBUFF,
308 				OTI6858_REQ_CHECK_TXBUFF,
309 				count, 0, allow, 1, 100);
310 		if (result != 1 || *allow != 0)
311 			count = 0;
312 		kfree(allow);
313 	}
314 
315 	if (count == 0) {
316 		priv->flags.write_urb_in_use = 0;
317 
318 		dbg("%s(): submitting interrupt urb", __func__);
319 		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
320 		if (result != 0) {
321 			dev_err(&port->dev, "%s(): usb_submit_urb() failed"
322 				" with error %d\n", __func__, result);
323 		}
324 		return;
325 	}
326 
327 	count = kfifo_out_locked(&port->write_fifo,
328 					port->write_urb->transfer_buffer,
329 					count, &port->lock);
330 	port->write_urb->transfer_buffer_length = count;
331 	result = usb_submit_urb(port->write_urb, GFP_NOIO);
332 	if (result != 0) {
333 		dev_err_console(port, "%s(): usb_submit_urb() failed"
334 			       " with error %d\n", __func__, result);
335 		priv->flags.write_urb_in_use = 0;
336 	}
337 
338 	usb_serial_port_softint(port);
339 }
340 
341 static int oti6858_startup(struct usb_serial *serial)
342 {
343 	struct usb_serial_port *port = serial->port[0];
344 	struct oti6858_private *priv;
345 	int i;
346 
347 	for (i = 0; i < serial->num_ports; ++i) {
348 		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
349 		if (!priv)
350 			break;
351 
352 		spin_lock_init(&priv->lock);
353 		init_waitqueue_head(&priv->intr_wait);
354 /*		INIT_WORK(&priv->setup_work, setup_line, serial->port[i]); */
355 /*		INIT_WORK(&priv->write_work, send_data, serial->port[i]); */
356 		priv->port = port;
357 		INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
358 		INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
359 
360 		usb_set_serial_port_data(serial->port[i], priv);
361 	}
362 	if (i == serial->num_ports)
363 		return 0;
364 
365 	for (--i; i >= 0; --i) {
366 		priv = usb_get_serial_port_data(serial->port[i]);
367 		kfree(priv);
368 		usb_set_serial_port_data(serial->port[i], NULL);
369 	}
370 	return -ENOMEM;
371 }
372 
373 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
374 			const unsigned char *buf, int count)
375 {
376 	if (!count)
377 		return count;
378 
379 	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
380 
381 	return count;
382 }
383 
384 static int oti6858_write_room(struct tty_struct *tty)
385 {
386 	struct usb_serial_port *port = tty->driver_data;
387 	int room = 0;
388 	unsigned long flags;
389 
390 	spin_lock_irqsave(&port->lock, flags);
391 	room = kfifo_avail(&port->write_fifo);
392 	spin_unlock_irqrestore(&port->lock, flags);
393 
394 	return room;
395 }
396 
397 static int oti6858_chars_in_buffer(struct tty_struct *tty)
398 {
399 	struct usb_serial_port *port = tty->driver_data;
400 	int chars = 0;
401 	unsigned long flags;
402 
403 	spin_lock_irqsave(&port->lock, flags);
404 	chars = kfifo_len(&port->write_fifo);
405 	spin_unlock_irqrestore(&port->lock, flags);
406 
407 	return chars;
408 }
409 
410 static void oti6858_init_termios(struct tty_struct *tty)
411 {
412 	*(tty->termios) = tty_std_termios;
413 	tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
414 	tty->termios->c_ispeed = 38400;
415 	tty->termios->c_ospeed = 38400;
416 }
417 
418 static void oti6858_set_termios(struct tty_struct *tty,
419 		struct usb_serial_port *port, struct ktermios *old_termios)
420 {
421 	struct oti6858_private *priv = usb_get_serial_port_data(port);
422 	unsigned long flags;
423 	unsigned int cflag;
424 	u8 frame_fmt, control;
425 	__le16 divisor;
426 	int br;
427 
428 	if (!tty) {
429 		dbg("%s(): no tty structures", __func__);
430 		return;
431 	}
432 
433 	cflag = tty->termios->c_cflag;
434 
435 	spin_lock_irqsave(&priv->lock, flags);
436 	divisor = priv->pending_setup.divisor;
437 	frame_fmt = priv->pending_setup.frame_fmt;
438 	control = priv->pending_setup.control;
439 	spin_unlock_irqrestore(&priv->lock, flags);
440 
441 	frame_fmt &= ~FMT_DATA_BITS_MASK;
442 	switch (cflag & CSIZE) {
443 	case CS5:
444 		frame_fmt |= FMT_DATA_BITS_5;
445 		break;
446 	case CS6:
447 		frame_fmt |= FMT_DATA_BITS_6;
448 		break;
449 	case CS7:
450 		frame_fmt |= FMT_DATA_BITS_7;
451 		break;
452 	default:
453 	case CS8:
454 		frame_fmt |= FMT_DATA_BITS_8;
455 		break;
456 	}
457 
458 	/* manufacturer claims that this device can work with baud rates
459 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
460 	 * guarantee that any other baud rate will work (especially
461 	 * the higher ones)
462 	 */
463 	br = tty_get_baud_rate(tty);
464 	if (br == 0) {
465 		divisor = 0;
466 	} else {
467 		int real_br;
468 		int new_divisor;
469 		br = min(br, OTI6858_MAX_BAUD_RATE);
470 
471 		new_divisor = (96000000 + 8 * br) / (16 * br);
472 		real_br = 96000000 / (16 * new_divisor);
473 		divisor = cpu_to_le16(new_divisor);
474 		tty_encode_baud_rate(tty, real_br, real_br);
475 	}
476 
477 	frame_fmt &= ~FMT_STOP_BITS_MASK;
478 	if ((cflag & CSTOPB) != 0)
479 		frame_fmt |= FMT_STOP_BITS_2;
480 	else
481 		frame_fmt |= FMT_STOP_BITS_1;
482 
483 	frame_fmt &= ~FMT_PARITY_MASK;
484 	if ((cflag & PARENB) != 0) {
485 		if ((cflag & PARODD) != 0)
486 			frame_fmt |= FMT_PARITY_ODD;
487 		else
488 			frame_fmt |= FMT_PARITY_EVEN;
489 	} else {
490 		frame_fmt |= FMT_PARITY_NONE;
491 	}
492 
493 	control &= ~CONTROL_MASK;
494 	if ((cflag & CRTSCTS) != 0)
495 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
496 
497 	/* change control lines if we are switching to or from B0 */
498 	/* FIXME:
499 	spin_lock_irqsave(&priv->lock, flags);
500 	control = priv->line_control;
501 	if ((cflag & CBAUD) == B0)
502 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
503 	else
504 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
505 	if (control != priv->line_control) {
506 		control = priv->line_control;
507 		spin_unlock_irqrestore(&priv->lock, flags);
508 		set_control_lines(serial->dev, control);
509 	} else {
510 		spin_unlock_irqrestore(&priv->lock, flags);
511 	}
512 	*/
513 
514 	spin_lock_irqsave(&priv->lock, flags);
515 	if (divisor != priv->pending_setup.divisor
516 			|| control != priv->pending_setup.control
517 			|| frame_fmt != priv->pending_setup.frame_fmt) {
518 		priv->pending_setup.divisor = divisor;
519 		priv->pending_setup.control = control;
520 		priv->pending_setup.frame_fmt = frame_fmt;
521 	}
522 	spin_unlock_irqrestore(&priv->lock, flags);
523 }
524 
525 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
526 {
527 	struct oti6858_private *priv = usb_get_serial_port_data(port);
528 	struct ktermios tmp_termios;
529 	struct usb_serial *serial = port->serial;
530 	struct oti6858_control_pkt *buf;
531 	unsigned long flags;
532 	int result;
533 
534 	usb_clear_halt(serial->dev, port->write_urb->pipe);
535 	usb_clear_halt(serial->dev, port->read_urb->pipe);
536 
537 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
538 	if (buf == NULL) {
539 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
540 		return -ENOMEM;
541 	}
542 
543 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
544 				OTI6858_REQ_T_GET_STATUS,
545 				OTI6858_REQ_GET_STATUS,
546 				0, 0,
547 				buf, OTI6858_CTRL_PKT_SIZE,
548 				100);
549 	if (result != OTI6858_CTRL_PKT_SIZE) {
550 		/* assume default (after power-on reset) values */
551 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
552 		buf->frame_fmt = 0x03;	/* 8N1 */
553 		buf->something = 0x43;
554 		buf->control = 0x4c;	/* DTR, RTS */
555 		buf->tx_status = 0x00;
556 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
557 		buf->rx_bytes_avail = 0x00;
558 	}
559 
560 	spin_lock_irqsave(&priv->lock, flags);
561 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
562 	priv->pending_setup.divisor = buf->divisor;
563 	priv->pending_setup.frame_fmt = buf->frame_fmt;
564 	priv->pending_setup.control = buf->control;
565 	spin_unlock_irqrestore(&priv->lock, flags);
566 	kfree(buf);
567 
568 	dbg("%s(): submitting interrupt urb", __func__);
569 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
570 	if (result != 0) {
571 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
572 			       " with error %d\n", __func__, result);
573 		oti6858_close(port);
574 		return result;
575 	}
576 
577 	/* setup termios */
578 	if (tty)
579 		oti6858_set_termios(tty, port, &tmp_termios);
580 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
581 	return 0;
582 }
583 
584 static void oti6858_close(struct usb_serial_port *port)
585 {
586 	struct oti6858_private *priv = usb_get_serial_port_data(port);
587 	unsigned long flags;
588 
589 	spin_lock_irqsave(&port->lock, flags);
590 	/* clear out any remaining data in the buffer */
591 	kfifo_reset_out(&port->write_fifo);
592 	spin_unlock_irqrestore(&port->lock, flags);
593 
594 	dbg("%s(): after buf_clear()", __func__);
595 
596 	/* cancel scheduled setup */
597 	cancel_delayed_work_sync(&priv->delayed_setup_work);
598 	cancel_delayed_work_sync(&priv->delayed_write_work);
599 
600 	/* shutdown our urbs */
601 	dbg("%s(): shutting down urbs", __func__);
602 	usb_kill_urb(port->write_urb);
603 	usb_kill_urb(port->read_urb);
604 	usb_kill_urb(port->interrupt_in_urb);
605 }
606 
607 static int oti6858_tiocmset(struct tty_struct *tty,
608 				unsigned int set, unsigned int clear)
609 {
610 	struct usb_serial_port *port = tty->driver_data;
611 	struct oti6858_private *priv = usb_get_serial_port_data(port);
612 	unsigned long flags;
613 	u8 control;
614 
615 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
616 				__func__, port->number, set, clear);
617 
618 	/* FIXME: check if this is correct (active high/low) */
619 	spin_lock_irqsave(&priv->lock, flags);
620 	control = priv->pending_setup.control;
621 	if ((set & TIOCM_RTS) != 0)
622 		control |= CONTROL_RTS_HIGH;
623 	if ((set & TIOCM_DTR) != 0)
624 		control |= CONTROL_DTR_HIGH;
625 	if ((clear & TIOCM_RTS) != 0)
626 		control &= ~CONTROL_RTS_HIGH;
627 	if ((clear & TIOCM_DTR) != 0)
628 		control &= ~CONTROL_DTR_HIGH;
629 
630 	if (control != priv->pending_setup.control)
631 		priv->pending_setup.control = control;
632 
633 	spin_unlock_irqrestore(&priv->lock, flags);
634 	return 0;
635 }
636 
637 static int oti6858_tiocmget(struct tty_struct *tty)
638 {
639 	struct usb_serial_port *port = tty->driver_data;
640 	struct oti6858_private *priv = usb_get_serial_port_data(port);
641 	unsigned long flags;
642 	unsigned pin_state;
643 	unsigned result = 0;
644 
645 	spin_lock_irqsave(&priv->lock, flags);
646 	pin_state = priv->status.pin_state & PIN_MASK;
647 	spin_unlock_irqrestore(&priv->lock, flags);
648 
649 	/* FIXME: check if this is correct (active high/low) */
650 	if ((pin_state & PIN_RTS) != 0)
651 		result |= TIOCM_RTS;
652 	if ((pin_state & PIN_CTS) != 0)
653 		result |= TIOCM_CTS;
654 	if ((pin_state & PIN_DSR) != 0)
655 		result |= TIOCM_DSR;
656 	if ((pin_state & PIN_DTR) != 0)
657 		result |= TIOCM_DTR;
658 	if ((pin_state & PIN_RI) != 0)
659 		result |= TIOCM_RI;
660 	if ((pin_state & PIN_DCD) != 0)
661 		result |= TIOCM_CD;
662 
663 	dbg("%s() = 0x%08x", __func__, result);
664 
665 	return result;
666 }
667 
668 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
669 {
670 	struct oti6858_private *priv = usb_get_serial_port_data(port);
671 	unsigned long flags;
672 	unsigned int prev, status;
673 	unsigned int changed;
674 
675 	spin_lock_irqsave(&priv->lock, flags);
676 	prev = priv->status.pin_state;
677 	spin_unlock_irqrestore(&priv->lock, flags);
678 
679 	while (1) {
680 		wait_event_interruptible(priv->intr_wait,
681 					priv->status.pin_state != prev);
682 		if (signal_pending(current))
683 			return -ERESTARTSYS;
684 
685 		spin_lock_irqsave(&priv->lock, flags);
686 		status = priv->status.pin_state & PIN_MASK;
687 		spin_unlock_irqrestore(&priv->lock, flags);
688 
689 		changed = prev ^ status;
690 		/* FIXME: check if this is correct (active high/low) */
691 		if (((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
692 		    ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
693 		    ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
694 		    ((arg & TIOCM_CTS) && (changed & PIN_CTS)))
695 			return 0;
696 		prev = status;
697 	}
698 
699 	/* NOTREACHED */
700 	return 0;
701 }
702 
703 static int oti6858_ioctl(struct tty_struct *tty,
704 			unsigned int cmd, unsigned long arg)
705 {
706 	struct usb_serial_port *port = tty->driver_data;
707 
708 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
709 				__func__, port->number, cmd, arg);
710 
711 	switch (cmd) {
712 	case TIOCMIWAIT:
713 		dbg("%s(): TIOCMIWAIT", __func__);
714 		return wait_modem_info(port, arg);
715 	default:
716 		dbg("%s(): 0x%04x not supported", __func__, cmd);
717 		break;
718 	}
719 	return -ENOIOCTLCMD;
720 }
721 
722 
723 static void oti6858_release(struct usb_serial *serial)
724 {
725 	int i;
726 
727 	for (i = 0; i < serial->num_ports; ++i)
728 		kfree(usb_get_serial_port_data(serial->port[i]));
729 }
730 
731 static void oti6858_read_int_callback(struct urb *urb)
732 {
733 	struct usb_serial_port *port =  urb->context;
734 	struct oti6858_private *priv = usb_get_serial_port_data(port);
735 	int transient = 0, can_recv = 0, resubmit = 1;
736 	int status = urb->status;
737 
738 	switch (status) {
739 	case 0:
740 		/* success */
741 		break;
742 	case -ECONNRESET:
743 	case -ENOENT:
744 	case -ESHUTDOWN:
745 		/* this urb is terminated, clean up */
746 		dbg("%s(): urb shutting down with status: %d",
747 					__func__, status);
748 		return;
749 	default:
750 		dbg("%s(): nonzero urb status received: %d",
751 					__func__, status);
752 		break;
753 	}
754 
755 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
756 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
757 		unsigned long flags;
758 
759 		spin_lock_irqsave(&priv->lock, flags);
760 
761 		if (!priv->transient) {
762 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
763 				if (xs->rx_bytes_avail == 0) {
764 					priv->transient = 4;
765 					priv->setup_done = 0;
766 					resubmit = 0;
767 					dbg("%s(): scheduling setup_line()",
768 					    __func__);
769 					schedule_delayed_work(&priv->delayed_setup_work, 0);
770 				}
771 			}
772 		} else {
773 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
774 				priv->transient = 0;
775 			} else if (!priv->setup_done) {
776 				resubmit = 0;
777 			} else if (--priv->transient == 0) {
778 				if (xs->rx_bytes_avail == 0) {
779 					priv->transient = 4;
780 					priv->setup_done = 0;
781 					resubmit = 0;
782 					dbg("%s(): scheduling setup_line()",
783 					    __func__);
784 					schedule_delayed_work(&priv->delayed_setup_work, 0);
785 				}
786 			}
787 		}
788 
789 		if (!priv->transient) {
790 			if (xs->pin_state != priv->status.pin_state)
791 				wake_up_interruptible(&priv->intr_wait);
792 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
793 		}
794 
795 		if (!priv->transient && xs->rx_bytes_avail != 0) {
796 			can_recv = xs->rx_bytes_avail;
797 			priv->flags.read_urb_in_use = 1;
798 		}
799 
800 		transient = priv->transient;
801 		spin_unlock_irqrestore(&priv->lock, flags);
802 	}
803 
804 	if (can_recv) {
805 		int result;
806 
807 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
808 		if (result != 0) {
809 			priv->flags.read_urb_in_use = 0;
810 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
811 					" error %d\n", __func__, result);
812 		} else {
813 			resubmit = 0;
814 		}
815 	} else if (!transient) {
816 		unsigned long flags;
817 		int count;
818 
819 		spin_lock_irqsave(&port->lock, flags);
820 		count = kfifo_len(&port->write_fifo);
821 		spin_unlock_irqrestore(&port->lock, flags);
822 
823 		spin_lock_irqsave(&priv->lock, flags);
824 		if (priv->flags.write_urb_in_use == 0 && count != 0) {
825 			schedule_delayed_work(&priv->delayed_write_work, 0);
826 			resubmit = 0;
827 		}
828 		spin_unlock_irqrestore(&priv->lock, flags);
829 	}
830 
831 	if (resubmit) {
832 		int result;
833 
834 /*		dbg("%s(): submitting interrupt urb", __func__); */
835 		result = usb_submit_urb(urb, GFP_ATOMIC);
836 		if (result != 0) {
837 			dev_err(&urb->dev->dev,
838 					"%s(): usb_submit_urb() failed with"
839 					" error %d\n", __func__, result);
840 		}
841 	}
842 }
843 
844 static void oti6858_read_bulk_callback(struct urb *urb)
845 {
846 	struct usb_serial_port *port =  urb->context;
847 	struct oti6858_private *priv = usb_get_serial_port_data(port);
848 	struct tty_struct *tty;
849 	unsigned char *data = urb->transfer_buffer;
850 	unsigned long flags;
851 	int status = urb->status;
852 	int result;
853 
854 	spin_lock_irqsave(&priv->lock, flags);
855 	priv->flags.read_urb_in_use = 0;
856 	spin_unlock_irqrestore(&priv->lock, flags);
857 
858 	if (status != 0) {
859 		dbg("%s(): unable to handle the error, exiting", __func__);
860 		return;
861 	}
862 
863 	tty = tty_port_tty_get(&port->port);
864 	if (tty != NULL && urb->actual_length > 0) {
865 		tty_insert_flip_string(tty, data, urb->actual_length);
866 		tty_flip_buffer_push(tty);
867 	}
868 	tty_kref_put(tty);
869 
870 	/* schedule the interrupt urb */
871 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
872 	if (result != 0 && result != -EPERM) {
873 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
874 				" error %d\n", __func__, result);
875 	}
876 }
877 
878 static void oti6858_write_bulk_callback(struct urb *urb)
879 {
880 	struct usb_serial_port *port =  urb->context;
881 	struct oti6858_private *priv = usb_get_serial_port_data(port);
882 	int status = urb->status;
883 	int result;
884 
885 	switch (status) {
886 	case 0:
887 		/* success */
888 		break;
889 	case -ECONNRESET:
890 	case -ENOENT:
891 	case -ESHUTDOWN:
892 		/* this urb is terminated, clean up */
893 		dbg("%s(): urb shutting down with status: %d",
894 					__func__, status);
895 		priv->flags.write_urb_in_use = 0;
896 		return;
897 	default:
898 		/* error in the urb, so we have to resubmit it */
899 		dbg("%s(): nonzero write bulk status received: %d",
900 					__func__, status);
901 		dbg("%s(): overflow in write", __func__);
902 
903 		port->write_urb->transfer_buffer_length = 1;
904 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
905 		if (result) {
906 			dev_err_console(port, "%s(): usb_submit_urb() failed,"
907 					" error %d\n", __func__, result);
908 		} else {
909 			return;
910 		}
911 	}
912 
913 	priv->flags.write_urb_in_use = 0;
914 
915 	/* schedule the interrupt urb if we are still open */
916 	dbg("%s(): submitting interrupt urb", __func__);
917 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
918 	if (result != 0) {
919 		dev_err(&port->dev, "%s(): failed submitting int urb,"
920 					" error %d\n", __func__, result);
921 	}
922 }
923 
924 module_usb_serial_driver(oti6858_driver, serial_drivers);
925 
926 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
927 MODULE_AUTHOR(OTI6858_AUTHOR);
928 MODULE_VERSION(OTI6858_VERSION);
929 MODULE_LICENSE("GPL");
930 
931 module_param(debug, bool, S_IRUGO | S_IWUSR);
932 MODULE_PARM_DESC(debug, "enable debug output");
933 
934