xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision c67e8ec0)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Ours Technology Inc. OTi-6858 USB to serial adapter driver.
4  *
5  * Copyleft  (C) 2007 Kees Lemmens (adapted for kernel 2.6.20)
6  * Copyright (C) 2006 Tomasz Michal Lukaszewski (FIXME: add e-mail)
7  * Copyright (C) 2001-2004 Greg Kroah-Hartman (greg@kroah.com)
8  * Copyright (C) 2003 IBM Corp.
9  *
10  * Many thanks to the authors of pl2303 driver: all functions in this file
11  * are heavily based on pl2303 code, buffering code is a 1-to-1 copy.
12  *
13  * Warning! You use this driver on your own risk! The only official
14  * description of this device I have is datasheet from manufacturer,
15  * and it doesn't contain almost any information needed to write a driver.
16  * Almost all knowlegde used while writing this driver was gathered by:
17  *  - analyzing traffic between device and the M$ Windows 2000 driver,
18  *  - trying different bit combinations and checking pin states
19  *    with a voltmeter,
20  *  - receiving malformed frames and producing buffer overflows
21  *    to learn how errors are reported,
22  * So, THIS CODE CAN DESTROY OTi-6858 AND ANY OTHER DEVICES, THAT ARE
23  * CONNECTED TO IT!
24  *
25  * See Documentation/usb/usb-serial.txt for more information on using this
26  * driver
27  *
28  * TODO:
29  *  - implement correct flushing for ioctls and oti6858_close()
30  *  - check how errors (rx overflow, parity error, framing error) are reported
31  *  - implement oti6858_break_ctl()
32  *  - implement more ioctls
33  *  - test/implement flow control
34  *  - allow setting custom baud rates
35  */
36 
37 #include <linux/kernel.h>
38 #include <linux/errno.h>
39 #include <linux/slab.h>
40 #include <linux/tty.h>
41 #include <linux/tty_driver.h>
42 #include <linux/tty_flip.h>
43 #include <linux/serial.h>
44 #include <linux/module.h>
45 #include <linux/moduleparam.h>
46 #include <linux/spinlock.h>
47 #include <linux/usb.h>
48 #include <linux/usb/serial.h>
49 #include <linux/uaccess.h>
50 #include <linux/kfifo.h>
51 #include "oti6858.h"
52 
53 #define OTI6858_DESCRIPTION \
54 	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"
55 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
56 
57 static const struct usb_device_id id_table[] = {
58 	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
59 	{ }
60 };
61 
62 MODULE_DEVICE_TABLE(usb, id_table);
63 
64 /* requests */
65 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
66 #define	OTI6858_REQ_T_GET_STATUS	0x01
67 
68 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
69 #define	OTI6858_REQ_T_SET_LINE		0x00
70 
71 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
72 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
73 
74 /* format of the control packet */
75 struct oti6858_control_pkt {
76 	__le16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
77 #define OTI6858_MAX_BAUD_RATE	3000000
78 	u8	frame_fmt;
79 #define FMT_STOP_BITS_MASK	0xc0
80 #define FMT_STOP_BITS_1		0x00
81 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
82 #define FMT_PARITY_MASK		0x38
83 #define FMT_PARITY_NONE		0x00
84 #define FMT_PARITY_ODD		0x08
85 #define FMT_PARITY_EVEN		0x18
86 #define FMT_PARITY_MARK		0x28
87 #define FMT_PARITY_SPACE	0x38
88 #define FMT_DATA_BITS_MASK	0x03
89 #define FMT_DATA_BITS_5		0x00
90 #define FMT_DATA_BITS_6		0x01
91 #define FMT_DATA_BITS_7		0x02
92 #define FMT_DATA_BITS_8		0x03
93 	u8	something;	/* always equals 0x43 */
94 	u8	control;	/* settings of flow control lines */
95 #define CONTROL_MASK		0x0c
96 #define CONTROL_DTR_HIGH	0x08
97 #define CONTROL_RTS_HIGH	0x04
98 	u8	tx_status;
99 #define	TX_BUFFER_EMPTIED	0x09
100 	u8	pin_state;
101 #define PIN_MASK		0x3f
102 #define PIN_MSR_MASK		0x1b
103 #define PIN_RTS			0x20	/* output pin */
104 #define PIN_CTS			0x10	/* input pin, active low */
105 #define PIN_DSR			0x08	/* input pin, active low */
106 #define PIN_DTR			0x04	/* output pin */
107 #define PIN_RI			0x02	/* input pin, active low */
108 #define PIN_DCD			0x01	/* input pin, active low */
109 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
110 };
111 
112 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
113 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
114 	(((a)->divisor == (priv)->pending_setup.divisor) \
115 	  && ((a)->control == (priv)->pending_setup.control) \
116 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt))
117 
118 /* function prototypes */
119 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port);
120 static void oti6858_close(struct usb_serial_port *port);
121 static void oti6858_set_termios(struct tty_struct *tty,
122 			struct usb_serial_port *port, struct ktermios *old);
123 static void oti6858_init_termios(struct tty_struct *tty);
124 static void oti6858_read_int_callback(struct urb *urb);
125 static void oti6858_read_bulk_callback(struct urb *urb);
126 static void oti6858_write_bulk_callback(struct urb *urb);
127 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
128 			const unsigned char *buf, int count);
129 static int oti6858_write_room(struct tty_struct *tty);
130 static int oti6858_chars_in_buffer(struct tty_struct *tty);
131 static int oti6858_tiocmget(struct tty_struct *tty);
132 static int oti6858_tiocmset(struct tty_struct *tty,
133 				unsigned int set, unsigned int clear);
134 static int oti6858_port_probe(struct usb_serial_port *port);
135 static int oti6858_port_remove(struct usb_serial_port *port);
136 
137 /* device info */
138 static struct usb_serial_driver oti6858_device = {
139 	.driver = {
140 		.owner =	THIS_MODULE,
141 		.name =		"oti6858",
142 	},
143 	.id_table =		id_table,
144 	.num_ports =		1,
145 	.num_bulk_in =		1,
146 	.num_bulk_out =		1,
147 	.num_interrupt_in =	1,
148 	.open =			oti6858_open,
149 	.close =		oti6858_close,
150 	.write =		oti6858_write,
151 	.set_termios =		oti6858_set_termios,
152 	.init_termios = 	oti6858_init_termios,
153 	.tiocmget =		oti6858_tiocmget,
154 	.tiocmset =		oti6858_tiocmset,
155 	.tiocmiwait =		usb_serial_generic_tiocmiwait,
156 	.read_bulk_callback =	oti6858_read_bulk_callback,
157 	.read_int_callback =	oti6858_read_int_callback,
158 	.write_bulk_callback =	oti6858_write_bulk_callback,
159 	.write_room =		oti6858_write_room,
160 	.chars_in_buffer =	oti6858_chars_in_buffer,
161 	.port_probe =		oti6858_port_probe,
162 	.port_remove =		oti6858_port_remove,
163 };
164 
165 static struct usb_serial_driver * const serial_drivers[] = {
166 	&oti6858_device, NULL
167 };
168 
169 struct oti6858_private {
170 	spinlock_t lock;
171 
172 	struct oti6858_control_pkt status;
173 
174 	struct {
175 		u8 read_urb_in_use;
176 		u8 write_urb_in_use;
177 	} flags;
178 	struct delayed_work delayed_write_work;
179 
180 	struct {
181 		__le16 divisor;
182 		u8 frame_fmt;
183 		u8 control;
184 	} pending_setup;
185 	u8 transient;
186 	u8 setup_done;
187 	struct delayed_work delayed_setup_work;
188 
189 	struct usb_serial_port *port;   /* USB port with which associated */
190 };
191 
192 static void setup_line(struct work_struct *work)
193 {
194 	struct oti6858_private *priv = container_of(work,
195 			struct oti6858_private, delayed_setup_work.work);
196 	struct usb_serial_port *port = priv->port;
197 	struct oti6858_control_pkt *new_setup;
198 	unsigned long flags;
199 	int result;
200 
201 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
202 	if (!new_setup) {
203 		/* we will try again */
204 		schedule_delayed_work(&priv->delayed_setup_work,
205 						msecs_to_jiffies(2));
206 		return;
207 	}
208 
209 	result = usb_control_msg(port->serial->dev,
210 				usb_rcvctrlpipe(port->serial->dev, 0),
211 				OTI6858_REQ_T_GET_STATUS,
212 				OTI6858_REQ_GET_STATUS,
213 				0, 0,
214 				new_setup, OTI6858_CTRL_PKT_SIZE,
215 				100);
216 
217 	if (result != OTI6858_CTRL_PKT_SIZE) {
218 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
219 		kfree(new_setup);
220 		/* we will try again */
221 		schedule_delayed_work(&priv->delayed_setup_work,
222 							msecs_to_jiffies(2));
223 		return;
224 	}
225 
226 	spin_lock_irqsave(&priv->lock, flags);
227 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
228 		new_setup->divisor = priv->pending_setup.divisor;
229 		new_setup->control = priv->pending_setup.control;
230 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
231 
232 		spin_unlock_irqrestore(&priv->lock, flags);
233 		result = usb_control_msg(port->serial->dev,
234 					usb_sndctrlpipe(port->serial->dev, 0),
235 					OTI6858_REQ_T_SET_LINE,
236 					OTI6858_REQ_SET_LINE,
237 					0, 0,
238 					new_setup, OTI6858_CTRL_PKT_SIZE,
239 					100);
240 	} else {
241 		spin_unlock_irqrestore(&priv->lock, flags);
242 		result = 0;
243 	}
244 	kfree(new_setup);
245 
246 	spin_lock_irqsave(&priv->lock, flags);
247 	if (result != OTI6858_CTRL_PKT_SIZE)
248 		priv->transient = 0;
249 	priv->setup_done = 1;
250 	spin_unlock_irqrestore(&priv->lock, flags);
251 
252 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
253 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
254 	if (result != 0) {
255 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
256 			__func__, result);
257 	}
258 }
259 
260 static void send_data(struct work_struct *work)
261 {
262 	struct oti6858_private *priv = container_of(work,
263 			struct oti6858_private, delayed_write_work.work);
264 	struct usb_serial_port *port = priv->port;
265 	int count = 0, result;
266 	unsigned long flags;
267 	u8 *allow;
268 
269 	spin_lock_irqsave(&priv->lock, flags);
270 	if (priv->flags.write_urb_in_use) {
271 		spin_unlock_irqrestore(&priv->lock, flags);
272 		schedule_delayed_work(&priv->delayed_write_work,
273 						msecs_to_jiffies(2));
274 		return;
275 	}
276 	priv->flags.write_urb_in_use = 1;
277 	spin_unlock_irqrestore(&priv->lock, flags);
278 
279 	spin_lock_irqsave(&port->lock, flags);
280 	count = kfifo_len(&port->write_fifo);
281 	spin_unlock_irqrestore(&port->lock, flags);
282 
283 	if (count > port->bulk_out_size)
284 		count = port->bulk_out_size;
285 
286 	if (count != 0) {
287 		allow = kmalloc(1, GFP_KERNEL);
288 		if (!allow)
289 			return;
290 
291 		result = usb_control_msg(port->serial->dev,
292 				usb_rcvctrlpipe(port->serial->dev, 0),
293 				OTI6858_REQ_T_CHECK_TXBUFF,
294 				OTI6858_REQ_CHECK_TXBUFF,
295 				count, 0, allow, 1, 100);
296 		if (result != 1 || *allow != 0)
297 			count = 0;
298 		kfree(allow);
299 	}
300 
301 	if (count == 0) {
302 		priv->flags.write_urb_in_use = 0;
303 
304 		dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
305 		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
306 		if (result != 0) {
307 			dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
308 				__func__, result);
309 		}
310 		return;
311 	}
312 
313 	count = kfifo_out_locked(&port->write_fifo,
314 					port->write_urb->transfer_buffer,
315 					count, &port->lock);
316 	port->write_urb->transfer_buffer_length = count;
317 	result = usb_submit_urb(port->write_urb, GFP_NOIO);
318 	if (result != 0) {
319 		dev_err_console(port, "%s(): usb_submit_urb() failed with error %d\n",
320 				__func__, result);
321 		priv->flags.write_urb_in_use = 0;
322 	}
323 
324 	usb_serial_port_softint(port);
325 }
326 
327 static int oti6858_port_probe(struct usb_serial_port *port)
328 {
329 	struct oti6858_private *priv;
330 
331 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
332 	if (!priv)
333 		return -ENOMEM;
334 
335 	spin_lock_init(&priv->lock);
336 	priv->port = port;
337 	INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
338 	INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
339 
340 	usb_set_serial_port_data(port, priv);
341 
342 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
343 
344 	return 0;
345 }
346 
347 static int oti6858_port_remove(struct usb_serial_port *port)
348 {
349 	struct oti6858_private *priv;
350 
351 	priv = usb_get_serial_port_data(port);
352 	kfree(priv);
353 
354 	return 0;
355 }
356 
357 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
358 			const unsigned char *buf, int count)
359 {
360 	if (!count)
361 		return count;
362 
363 	count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
364 
365 	return count;
366 }
367 
368 static int oti6858_write_room(struct tty_struct *tty)
369 {
370 	struct usb_serial_port *port = tty->driver_data;
371 	int room = 0;
372 	unsigned long flags;
373 
374 	spin_lock_irqsave(&port->lock, flags);
375 	room = kfifo_avail(&port->write_fifo);
376 	spin_unlock_irqrestore(&port->lock, flags);
377 
378 	return room;
379 }
380 
381 static int oti6858_chars_in_buffer(struct tty_struct *tty)
382 {
383 	struct usb_serial_port *port = tty->driver_data;
384 	int chars = 0;
385 	unsigned long flags;
386 
387 	spin_lock_irqsave(&port->lock, flags);
388 	chars = kfifo_len(&port->write_fifo);
389 	spin_unlock_irqrestore(&port->lock, flags);
390 
391 	return chars;
392 }
393 
394 static void oti6858_init_termios(struct tty_struct *tty)
395 {
396 	tty->termios = tty_std_termios;
397 	tty->termios.c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
398 	tty->termios.c_ispeed = 38400;
399 	tty->termios.c_ospeed = 38400;
400 }
401 
402 static void oti6858_set_termios(struct tty_struct *tty,
403 		struct usb_serial_port *port, struct ktermios *old_termios)
404 {
405 	struct oti6858_private *priv = usb_get_serial_port_data(port);
406 	unsigned long flags;
407 	unsigned int cflag;
408 	u8 frame_fmt, control;
409 	__le16 divisor;
410 	int br;
411 
412 	cflag = tty->termios.c_cflag;
413 
414 	spin_lock_irqsave(&priv->lock, flags);
415 	divisor = priv->pending_setup.divisor;
416 	frame_fmt = priv->pending_setup.frame_fmt;
417 	control = priv->pending_setup.control;
418 	spin_unlock_irqrestore(&priv->lock, flags);
419 
420 	frame_fmt &= ~FMT_DATA_BITS_MASK;
421 	switch (cflag & CSIZE) {
422 	case CS5:
423 		frame_fmt |= FMT_DATA_BITS_5;
424 		break;
425 	case CS6:
426 		frame_fmt |= FMT_DATA_BITS_6;
427 		break;
428 	case CS7:
429 		frame_fmt |= FMT_DATA_BITS_7;
430 		break;
431 	default:
432 	case CS8:
433 		frame_fmt |= FMT_DATA_BITS_8;
434 		break;
435 	}
436 
437 	/* manufacturer claims that this device can work with baud rates
438 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
439 	 * guarantee that any other baud rate will work (especially
440 	 * the higher ones)
441 	 */
442 	br = tty_get_baud_rate(tty);
443 	if (br == 0) {
444 		divisor = 0;
445 	} else {
446 		int real_br;
447 		int new_divisor;
448 		br = min(br, OTI6858_MAX_BAUD_RATE);
449 
450 		new_divisor = (96000000 + 8 * br) / (16 * br);
451 		real_br = 96000000 / (16 * new_divisor);
452 		divisor = cpu_to_le16(new_divisor);
453 		tty_encode_baud_rate(tty, real_br, real_br);
454 	}
455 
456 	frame_fmt &= ~FMT_STOP_BITS_MASK;
457 	if ((cflag & CSTOPB) != 0)
458 		frame_fmt |= FMT_STOP_BITS_2;
459 	else
460 		frame_fmt |= FMT_STOP_BITS_1;
461 
462 	frame_fmt &= ~FMT_PARITY_MASK;
463 	if ((cflag & PARENB) != 0) {
464 		if ((cflag & PARODD) != 0)
465 			frame_fmt |= FMT_PARITY_ODD;
466 		else
467 			frame_fmt |= FMT_PARITY_EVEN;
468 	} else {
469 		frame_fmt |= FMT_PARITY_NONE;
470 	}
471 
472 	control &= ~CONTROL_MASK;
473 	if ((cflag & CRTSCTS) != 0)
474 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
475 
476 	/* change control lines if we are switching to or from B0 */
477 	/* FIXME:
478 	spin_lock_irqsave(&priv->lock, flags);
479 	control = priv->line_control;
480 	if ((cflag & CBAUD) == B0)
481 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
482 	else
483 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
484 	if (control != priv->line_control) {
485 		control = priv->line_control;
486 		spin_unlock_irqrestore(&priv->lock, flags);
487 		set_control_lines(serial->dev, control);
488 	} else {
489 		spin_unlock_irqrestore(&priv->lock, flags);
490 	}
491 	*/
492 
493 	spin_lock_irqsave(&priv->lock, flags);
494 	if (divisor != priv->pending_setup.divisor
495 			|| control != priv->pending_setup.control
496 			|| frame_fmt != priv->pending_setup.frame_fmt) {
497 		priv->pending_setup.divisor = divisor;
498 		priv->pending_setup.control = control;
499 		priv->pending_setup.frame_fmt = frame_fmt;
500 	}
501 	spin_unlock_irqrestore(&priv->lock, flags);
502 }
503 
504 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
505 {
506 	struct oti6858_private *priv = usb_get_serial_port_data(port);
507 	struct usb_serial *serial = port->serial;
508 	struct oti6858_control_pkt *buf;
509 	unsigned long flags;
510 	int result;
511 
512 	usb_clear_halt(serial->dev, port->write_urb->pipe);
513 	usb_clear_halt(serial->dev, port->read_urb->pipe);
514 
515 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
516 	if (!buf)
517 		return -ENOMEM;
518 
519 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
520 				OTI6858_REQ_T_GET_STATUS,
521 				OTI6858_REQ_GET_STATUS,
522 				0, 0,
523 				buf, OTI6858_CTRL_PKT_SIZE,
524 				100);
525 	if (result != OTI6858_CTRL_PKT_SIZE) {
526 		/* assume default (after power-on reset) values */
527 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
528 		buf->frame_fmt = 0x03;	/* 8N1 */
529 		buf->something = 0x43;
530 		buf->control = 0x4c;	/* DTR, RTS */
531 		buf->tx_status = 0x00;
532 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
533 		buf->rx_bytes_avail = 0x00;
534 	}
535 
536 	spin_lock_irqsave(&priv->lock, flags);
537 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
538 	priv->pending_setup.divisor = buf->divisor;
539 	priv->pending_setup.frame_fmt = buf->frame_fmt;
540 	priv->pending_setup.control = buf->control;
541 	spin_unlock_irqrestore(&priv->lock, flags);
542 	kfree(buf);
543 
544 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
545 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
546 	if (result != 0) {
547 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
548 			__func__, result);
549 		oti6858_close(port);
550 		return result;
551 	}
552 
553 	/* setup termios */
554 	if (tty)
555 		oti6858_set_termios(tty, port, NULL);
556 
557 	return 0;
558 }
559 
560 static void oti6858_close(struct usb_serial_port *port)
561 {
562 	struct oti6858_private *priv = usb_get_serial_port_data(port);
563 	unsigned long flags;
564 
565 	spin_lock_irqsave(&port->lock, flags);
566 	/* clear out any remaining data in the buffer */
567 	kfifo_reset_out(&port->write_fifo);
568 	spin_unlock_irqrestore(&port->lock, flags);
569 
570 	dev_dbg(&port->dev, "%s(): after buf_clear()\n", __func__);
571 
572 	/* cancel scheduled setup */
573 	cancel_delayed_work_sync(&priv->delayed_setup_work);
574 	cancel_delayed_work_sync(&priv->delayed_write_work);
575 
576 	/* shutdown our urbs */
577 	dev_dbg(&port->dev, "%s(): shutting down urbs\n", __func__);
578 	usb_kill_urb(port->write_urb);
579 	usb_kill_urb(port->read_urb);
580 	usb_kill_urb(port->interrupt_in_urb);
581 }
582 
583 static int oti6858_tiocmset(struct tty_struct *tty,
584 				unsigned int set, unsigned int clear)
585 {
586 	struct usb_serial_port *port = tty->driver_data;
587 	struct oti6858_private *priv = usb_get_serial_port_data(port);
588 	unsigned long flags;
589 	u8 control;
590 
591 	dev_dbg(&port->dev, "%s(set = 0x%08x, clear = 0x%08x)\n",
592 		__func__, set, clear);
593 
594 	/* FIXME: check if this is correct (active high/low) */
595 	spin_lock_irqsave(&priv->lock, flags);
596 	control = priv->pending_setup.control;
597 	if ((set & TIOCM_RTS) != 0)
598 		control |= CONTROL_RTS_HIGH;
599 	if ((set & TIOCM_DTR) != 0)
600 		control |= CONTROL_DTR_HIGH;
601 	if ((clear & TIOCM_RTS) != 0)
602 		control &= ~CONTROL_RTS_HIGH;
603 	if ((clear & TIOCM_DTR) != 0)
604 		control &= ~CONTROL_DTR_HIGH;
605 
606 	if (control != priv->pending_setup.control)
607 		priv->pending_setup.control = control;
608 
609 	spin_unlock_irqrestore(&priv->lock, flags);
610 	return 0;
611 }
612 
613 static int oti6858_tiocmget(struct tty_struct *tty)
614 {
615 	struct usb_serial_port *port = tty->driver_data;
616 	struct oti6858_private *priv = usb_get_serial_port_data(port);
617 	unsigned long flags;
618 	unsigned pin_state;
619 	unsigned result = 0;
620 
621 	spin_lock_irqsave(&priv->lock, flags);
622 	pin_state = priv->status.pin_state & PIN_MASK;
623 	spin_unlock_irqrestore(&priv->lock, flags);
624 
625 	/* FIXME: check if this is correct (active high/low) */
626 	if ((pin_state & PIN_RTS) != 0)
627 		result |= TIOCM_RTS;
628 	if ((pin_state & PIN_CTS) != 0)
629 		result |= TIOCM_CTS;
630 	if ((pin_state & PIN_DSR) != 0)
631 		result |= TIOCM_DSR;
632 	if ((pin_state & PIN_DTR) != 0)
633 		result |= TIOCM_DTR;
634 	if ((pin_state & PIN_RI) != 0)
635 		result |= TIOCM_RI;
636 	if ((pin_state & PIN_DCD) != 0)
637 		result |= TIOCM_CD;
638 
639 	dev_dbg(&port->dev, "%s() = 0x%08x\n", __func__, result);
640 
641 	return result;
642 }
643 
644 static void oti6858_read_int_callback(struct urb *urb)
645 {
646 	struct usb_serial_port *port =  urb->context;
647 	struct oti6858_private *priv = usb_get_serial_port_data(port);
648 	int transient = 0, can_recv = 0, resubmit = 1;
649 	int status = urb->status;
650 
651 	switch (status) {
652 	case 0:
653 		/* success */
654 		break;
655 	case -ECONNRESET:
656 	case -ENOENT:
657 	case -ESHUTDOWN:
658 		/* this urb is terminated, clean up */
659 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n",
660 			__func__, status);
661 		return;
662 	default:
663 		dev_dbg(&urb->dev->dev, "%s(): nonzero urb status received: %d\n",
664 			__func__, status);
665 		break;
666 	}
667 
668 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
669 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
670 		unsigned long flags;
671 
672 		spin_lock_irqsave(&priv->lock, flags);
673 
674 		if (!priv->transient) {
675 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
676 				if (xs->rx_bytes_avail == 0) {
677 					priv->transient = 4;
678 					priv->setup_done = 0;
679 					resubmit = 0;
680 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
681 					schedule_delayed_work(&priv->delayed_setup_work, 0);
682 				}
683 			}
684 		} else {
685 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
686 				priv->transient = 0;
687 			} else if (!priv->setup_done) {
688 				resubmit = 0;
689 			} else if (--priv->transient == 0) {
690 				if (xs->rx_bytes_avail == 0) {
691 					priv->transient = 4;
692 					priv->setup_done = 0;
693 					resubmit = 0;
694 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
695 					schedule_delayed_work(&priv->delayed_setup_work, 0);
696 				}
697 			}
698 		}
699 
700 		if (!priv->transient) {
701 			u8 delta = xs->pin_state ^ priv->status.pin_state;
702 
703 			if (delta & PIN_MSR_MASK) {
704 				if (delta & PIN_CTS)
705 					port->icount.cts++;
706 				if (delta & PIN_DSR)
707 					port->icount.dsr++;
708 				if (delta & PIN_RI)
709 					port->icount.rng++;
710 				if (delta & PIN_DCD)
711 					port->icount.dcd++;
712 
713 				wake_up_interruptible(&port->port.delta_msr_wait);
714 			}
715 
716 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
717 		}
718 
719 		if (!priv->transient && xs->rx_bytes_avail != 0) {
720 			can_recv = xs->rx_bytes_avail;
721 			priv->flags.read_urb_in_use = 1;
722 		}
723 
724 		transient = priv->transient;
725 		spin_unlock_irqrestore(&priv->lock, flags);
726 	}
727 
728 	if (can_recv) {
729 		int result;
730 
731 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
732 		if (result != 0) {
733 			priv->flags.read_urb_in_use = 0;
734 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
735 					" error %d\n", __func__, result);
736 		} else {
737 			resubmit = 0;
738 		}
739 	} else if (!transient) {
740 		unsigned long flags;
741 		int count;
742 
743 		spin_lock_irqsave(&port->lock, flags);
744 		count = kfifo_len(&port->write_fifo);
745 		spin_unlock_irqrestore(&port->lock, flags);
746 
747 		spin_lock_irqsave(&priv->lock, flags);
748 		if (priv->flags.write_urb_in_use == 0 && count != 0) {
749 			schedule_delayed_work(&priv->delayed_write_work, 0);
750 			resubmit = 0;
751 		}
752 		spin_unlock_irqrestore(&priv->lock, flags);
753 	}
754 
755 	if (resubmit) {
756 		int result;
757 
758 /*		dev_dbg(&urb->dev->dev, "%s(): submitting interrupt urb\n", __func__); */
759 		result = usb_submit_urb(urb, GFP_ATOMIC);
760 		if (result != 0) {
761 			dev_err(&urb->dev->dev,
762 					"%s(): usb_submit_urb() failed with"
763 					" error %d\n", __func__, result);
764 		}
765 	}
766 }
767 
768 static void oti6858_read_bulk_callback(struct urb *urb)
769 {
770 	struct usb_serial_port *port =  urb->context;
771 	struct oti6858_private *priv = usb_get_serial_port_data(port);
772 	unsigned char *data = urb->transfer_buffer;
773 	unsigned long flags;
774 	int status = urb->status;
775 	int result;
776 
777 	spin_lock_irqsave(&priv->lock, flags);
778 	priv->flags.read_urb_in_use = 0;
779 	spin_unlock_irqrestore(&priv->lock, flags);
780 
781 	if (status != 0) {
782 		dev_dbg(&urb->dev->dev, "%s(): unable to handle the error, exiting\n", __func__);
783 		return;
784 	}
785 
786 	if (urb->actual_length > 0) {
787 		tty_insert_flip_string(&port->port, data, urb->actual_length);
788 		tty_flip_buffer_push(&port->port);
789 	}
790 
791 	/* schedule the interrupt urb */
792 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
793 	if (result != 0 && result != -EPERM) {
794 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
795 				" error %d\n", __func__, result);
796 	}
797 }
798 
799 static void oti6858_write_bulk_callback(struct urb *urb)
800 {
801 	struct usb_serial_port *port =  urb->context;
802 	struct oti6858_private *priv = usb_get_serial_port_data(port);
803 	int status = urb->status;
804 	int result;
805 
806 	switch (status) {
807 	case 0:
808 		/* success */
809 		break;
810 	case -ECONNRESET:
811 	case -ENOENT:
812 	case -ESHUTDOWN:
813 		/* this urb is terminated, clean up */
814 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n", __func__, status);
815 		priv->flags.write_urb_in_use = 0;
816 		return;
817 	default:
818 		/* error in the urb, so we have to resubmit it */
819 		dev_dbg(&urb->dev->dev, "%s(): nonzero write bulk status received: %d\n", __func__, status);
820 		dev_dbg(&urb->dev->dev, "%s(): overflow in write\n", __func__);
821 
822 		port->write_urb->transfer_buffer_length = 1;
823 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
824 		if (result) {
825 			dev_err_console(port, "%s(): usb_submit_urb() failed,"
826 					" error %d\n", __func__, result);
827 		} else {
828 			return;
829 		}
830 	}
831 
832 	priv->flags.write_urb_in_use = 0;
833 
834 	/* schedule the interrupt urb if we are still open */
835 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
836 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
837 	if (result != 0) {
838 		dev_err(&port->dev, "%s(): failed submitting int urb,"
839 					" error %d\n", __func__, result);
840 	}
841 }
842 
843 module_usb_serial_driver(serial_drivers, id_table);
844 
845 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
846 MODULE_AUTHOR(OTI6858_AUTHOR);
847 MODULE_LICENSE("GPL v2");
848