xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision e15a5365)
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.rst 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_encode_baud_rate(tty, 38400, 38400);
397 }
398 
399 static void oti6858_set_termios(struct tty_struct *tty,
400 		struct usb_serial_port *port, struct ktermios *old_termios)
401 {
402 	struct oti6858_private *priv = usb_get_serial_port_data(port);
403 	unsigned long flags;
404 	unsigned int cflag;
405 	u8 frame_fmt, control;
406 	__le16 divisor;
407 	int br;
408 
409 	cflag = tty->termios.c_cflag;
410 
411 	spin_lock_irqsave(&priv->lock, flags);
412 	divisor = priv->pending_setup.divisor;
413 	frame_fmt = priv->pending_setup.frame_fmt;
414 	control = priv->pending_setup.control;
415 	spin_unlock_irqrestore(&priv->lock, flags);
416 
417 	frame_fmt &= ~FMT_DATA_BITS_MASK;
418 	switch (cflag & CSIZE) {
419 	case CS5:
420 		frame_fmt |= FMT_DATA_BITS_5;
421 		break;
422 	case CS6:
423 		frame_fmt |= FMT_DATA_BITS_6;
424 		break;
425 	case CS7:
426 		frame_fmt |= FMT_DATA_BITS_7;
427 		break;
428 	default:
429 	case CS8:
430 		frame_fmt |= FMT_DATA_BITS_8;
431 		break;
432 	}
433 
434 	/* manufacturer claims that this device can work with baud rates
435 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
436 	 * guarantee that any other baud rate will work (especially
437 	 * the higher ones)
438 	 */
439 	br = tty_get_baud_rate(tty);
440 	if (br == 0) {
441 		divisor = 0;
442 	} else {
443 		int real_br;
444 		int new_divisor;
445 		br = min(br, OTI6858_MAX_BAUD_RATE);
446 
447 		new_divisor = (96000000 + 8 * br) / (16 * br);
448 		real_br = 96000000 / (16 * new_divisor);
449 		divisor = cpu_to_le16(new_divisor);
450 		tty_encode_baud_rate(tty, real_br, real_br);
451 	}
452 
453 	frame_fmt &= ~FMT_STOP_BITS_MASK;
454 	if ((cflag & CSTOPB) != 0)
455 		frame_fmt |= FMT_STOP_BITS_2;
456 	else
457 		frame_fmt |= FMT_STOP_BITS_1;
458 
459 	frame_fmt &= ~FMT_PARITY_MASK;
460 	if ((cflag & PARENB) != 0) {
461 		if ((cflag & PARODD) != 0)
462 			frame_fmt |= FMT_PARITY_ODD;
463 		else
464 			frame_fmt |= FMT_PARITY_EVEN;
465 	} else {
466 		frame_fmt |= FMT_PARITY_NONE;
467 	}
468 
469 	control &= ~CONTROL_MASK;
470 	if ((cflag & CRTSCTS) != 0)
471 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
472 
473 	/* change control lines if we are switching to or from B0 */
474 	/* FIXME:
475 	spin_lock_irqsave(&priv->lock, flags);
476 	control = priv->line_control;
477 	if ((cflag & CBAUD) == B0)
478 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
479 	else
480 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
481 	if (control != priv->line_control) {
482 		control = priv->line_control;
483 		spin_unlock_irqrestore(&priv->lock, flags);
484 		set_control_lines(serial->dev, control);
485 	} else {
486 		spin_unlock_irqrestore(&priv->lock, flags);
487 	}
488 	*/
489 
490 	spin_lock_irqsave(&priv->lock, flags);
491 	if (divisor != priv->pending_setup.divisor
492 			|| control != priv->pending_setup.control
493 			|| frame_fmt != priv->pending_setup.frame_fmt) {
494 		priv->pending_setup.divisor = divisor;
495 		priv->pending_setup.control = control;
496 		priv->pending_setup.frame_fmt = frame_fmt;
497 	}
498 	spin_unlock_irqrestore(&priv->lock, flags);
499 }
500 
501 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
502 {
503 	struct oti6858_private *priv = usb_get_serial_port_data(port);
504 	struct usb_serial *serial = port->serial;
505 	struct oti6858_control_pkt *buf;
506 	unsigned long flags;
507 	int result;
508 
509 	usb_clear_halt(serial->dev, port->write_urb->pipe);
510 	usb_clear_halt(serial->dev, port->read_urb->pipe);
511 
512 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
513 	if (!buf)
514 		return -ENOMEM;
515 
516 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
517 				OTI6858_REQ_T_GET_STATUS,
518 				OTI6858_REQ_GET_STATUS,
519 				0, 0,
520 				buf, OTI6858_CTRL_PKT_SIZE,
521 				100);
522 	if (result != OTI6858_CTRL_PKT_SIZE) {
523 		/* assume default (after power-on reset) values */
524 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
525 		buf->frame_fmt = 0x03;	/* 8N1 */
526 		buf->something = 0x43;
527 		buf->control = 0x4c;	/* DTR, RTS */
528 		buf->tx_status = 0x00;
529 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
530 		buf->rx_bytes_avail = 0x00;
531 	}
532 
533 	spin_lock_irqsave(&priv->lock, flags);
534 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
535 	priv->pending_setup.divisor = buf->divisor;
536 	priv->pending_setup.frame_fmt = buf->frame_fmt;
537 	priv->pending_setup.control = buf->control;
538 	spin_unlock_irqrestore(&priv->lock, flags);
539 	kfree(buf);
540 
541 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
542 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
543 	if (result != 0) {
544 		dev_err(&port->dev, "%s(): usb_submit_urb() failed with error %d\n",
545 			__func__, result);
546 		oti6858_close(port);
547 		return result;
548 	}
549 
550 	/* setup termios */
551 	if (tty)
552 		oti6858_set_termios(tty, port, NULL);
553 
554 	return 0;
555 }
556 
557 static void oti6858_close(struct usb_serial_port *port)
558 {
559 	struct oti6858_private *priv = usb_get_serial_port_data(port);
560 	unsigned long flags;
561 
562 	spin_lock_irqsave(&port->lock, flags);
563 	/* clear out any remaining data in the buffer */
564 	kfifo_reset_out(&port->write_fifo);
565 	spin_unlock_irqrestore(&port->lock, flags);
566 
567 	dev_dbg(&port->dev, "%s(): after buf_clear()\n", __func__);
568 
569 	/* cancel scheduled setup */
570 	cancel_delayed_work_sync(&priv->delayed_setup_work);
571 	cancel_delayed_work_sync(&priv->delayed_write_work);
572 
573 	/* shutdown our urbs */
574 	dev_dbg(&port->dev, "%s(): shutting down urbs\n", __func__);
575 	usb_kill_urb(port->write_urb);
576 	usb_kill_urb(port->read_urb);
577 	usb_kill_urb(port->interrupt_in_urb);
578 }
579 
580 static int oti6858_tiocmset(struct tty_struct *tty,
581 				unsigned int set, unsigned int clear)
582 {
583 	struct usb_serial_port *port = tty->driver_data;
584 	struct oti6858_private *priv = usb_get_serial_port_data(port);
585 	unsigned long flags;
586 	u8 control;
587 
588 	dev_dbg(&port->dev, "%s(set = 0x%08x, clear = 0x%08x)\n",
589 		__func__, set, clear);
590 
591 	/* FIXME: check if this is correct (active high/low) */
592 	spin_lock_irqsave(&priv->lock, flags);
593 	control = priv->pending_setup.control;
594 	if ((set & TIOCM_RTS) != 0)
595 		control |= CONTROL_RTS_HIGH;
596 	if ((set & TIOCM_DTR) != 0)
597 		control |= CONTROL_DTR_HIGH;
598 	if ((clear & TIOCM_RTS) != 0)
599 		control &= ~CONTROL_RTS_HIGH;
600 	if ((clear & TIOCM_DTR) != 0)
601 		control &= ~CONTROL_DTR_HIGH;
602 
603 	if (control != priv->pending_setup.control)
604 		priv->pending_setup.control = control;
605 
606 	spin_unlock_irqrestore(&priv->lock, flags);
607 	return 0;
608 }
609 
610 static int oti6858_tiocmget(struct tty_struct *tty)
611 {
612 	struct usb_serial_port *port = tty->driver_data;
613 	struct oti6858_private *priv = usb_get_serial_port_data(port);
614 	unsigned long flags;
615 	unsigned pin_state;
616 	unsigned result = 0;
617 
618 	spin_lock_irqsave(&priv->lock, flags);
619 	pin_state = priv->status.pin_state & PIN_MASK;
620 	spin_unlock_irqrestore(&priv->lock, flags);
621 
622 	/* FIXME: check if this is correct (active high/low) */
623 	if ((pin_state & PIN_RTS) != 0)
624 		result |= TIOCM_RTS;
625 	if ((pin_state & PIN_CTS) != 0)
626 		result |= TIOCM_CTS;
627 	if ((pin_state & PIN_DSR) != 0)
628 		result |= TIOCM_DSR;
629 	if ((pin_state & PIN_DTR) != 0)
630 		result |= TIOCM_DTR;
631 	if ((pin_state & PIN_RI) != 0)
632 		result |= TIOCM_RI;
633 	if ((pin_state & PIN_DCD) != 0)
634 		result |= TIOCM_CD;
635 
636 	dev_dbg(&port->dev, "%s() = 0x%08x\n", __func__, result);
637 
638 	return result;
639 }
640 
641 static void oti6858_read_int_callback(struct urb *urb)
642 {
643 	struct usb_serial_port *port =  urb->context;
644 	struct oti6858_private *priv = usb_get_serial_port_data(port);
645 	int transient = 0, can_recv = 0, resubmit = 1;
646 	int status = urb->status;
647 
648 	switch (status) {
649 	case 0:
650 		/* success */
651 		break;
652 	case -ECONNRESET:
653 	case -ENOENT:
654 	case -ESHUTDOWN:
655 		/* this urb is terminated, clean up */
656 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n",
657 			__func__, status);
658 		return;
659 	default:
660 		dev_dbg(&urb->dev->dev, "%s(): nonzero urb status received: %d\n",
661 			__func__, status);
662 		break;
663 	}
664 
665 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
666 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
667 		unsigned long flags;
668 
669 		spin_lock_irqsave(&priv->lock, flags);
670 
671 		if (!priv->transient) {
672 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
673 				if (xs->rx_bytes_avail == 0) {
674 					priv->transient = 4;
675 					priv->setup_done = 0;
676 					resubmit = 0;
677 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
678 					schedule_delayed_work(&priv->delayed_setup_work, 0);
679 				}
680 			}
681 		} else {
682 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
683 				priv->transient = 0;
684 			} else if (!priv->setup_done) {
685 				resubmit = 0;
686 			} else if (--priv->transient == 0) {
687 				if (xs->rx_bytes_avail == 0) {
688 					priv->transient = 4;
689 					priv->setup_done = 0;
690 					resubmit = 0;
691 					dev_dbg(&port->dev, "%s(): scheduling setup_line()\n", __func__);
692 					schedule_delayed_work(&priv->delayed_setup_work, 0);
693 				}
694 			}
695 		}
696 
697 		if (!priv->transient) {
698 			u8 delta = xs->pin_state ^ priv->status.pin_state;
699 
700 			if (delta & PIN_MSR_MASK) {
701 				if (delta & PIN_CTS)
702 					port->icount.cts++;
703 				if (delta & PIN_DSR)
704 					port->icount.dsr++;
705 				if (delta & PIN_RI)
706 					port->icount.rng++;
707 				if (delta & PIN_DCD)
708 					port->icount.dcd++;
709 
710 				wake_up_interruptible(&port->port.delta_msr_wait);
711 			}
712 
713 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
714 		}
715 
716 		if (!priv->transient && xs->rx_bytes_avail != 0) {
717 			can_recv = xs->rx_bytes_avail;
718 			priv->flags.read_urb_in_use = 1;
719 		}
720 
721 		transient = priv->transient;
722 		spin_unlock_irqrestore(&priv->lock, flags);
723 	}
724 
725 	if (can_recv) {
726 		int result;
727 
728 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
729 		if (result != 0) {
730 			priv->flags.read_urb_in_use = 0;
731 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
732 					" error %d\n", __func__, result);
733 		} else {
734 			resubmit = 0;
735 		}
736 	} else if (!transient) {
737 		unsigned long flags;
738 		int count;
739 
740 		spin_lock_irqsave(&port->lock, flags);
741 		count = kfifo_len(&port->write_fifo);
742 		spin_unlock_irqrestore(&port->lock, flags);
743 
744 		spin_lock_irqsave(&priv->lock, flags);
745 		if (priv->flags.write_urb_in_use == 0 && count != 0) {
746 			schedule_delayed_work(&priv->delayed_write_work, 0);
747 			resubmit = 0;
748 		}
749 		spin_unlock_irqrestore(&priv->lock, flags);
750 	}
751 
752 	if (resubmit) {
753 		int result;
754 
755 /*		dev_dbg(&urb->dev->dev, "%s(): submitting interrupt urb\n", __func__); */
756 		result = usb_submit_urb(urb, GFP_ATOMIC);
757 		if (result != 0) {
758 			dev_err(&urb->dev->dev,
759 					"%s(): usb_submit_urb() failed with"
760 					" error %d\n", __func__, result);
761 		}
762 	}
763 }
764 
765 static void oti6858_read_bulk_callback(struct urb *urb)
766 {
767 	struct usb_serial_port *port =  urb->context;
768 	struct oti6858_private *priv = usb_get_serial_port_data(port);
769 	unsigned char *data = urb->transfer_buffer;
770 	unsigned long flags;
771 	int status = urb->status;
772 	int result;
773 
774 	spin_lock_irqsave(&priv->lock, flags);
775 	priv->flags.read_urb_in_use = 0;
776 	spin_unlock_irqrestore(&priv->lock, flags);
777 
778 	if (status != 0) {
779 		dev_dbg(&urb->dev->dev, "%s(): unable to handle the error, exiting\n", __func__);
780 		return;
781 	}
782 
783 	if (urb->actual_length > 0) {
784 		tty_insert_flip_string(&port->port, data, urb->actual_length);
785 		tty_flip_buffer_push(&port->port);
786 	}
787 
788 	/* schedule the interrupt urb */
789 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
790 	if (result != 0 && result != -EPERM) {
791 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
792 				" error %d\n", __func__, result);
793 	}
794 }
795 
796 static void oti6858_write_bulk_callback(struct urb *urb)
797 {
798 	struct usb_serial_port *port =  urb->context;
799 	struct oti6858_private *priv = usb_get_serial_port_data(port);
800 	int status = urb->status;
801 	int result;
802 
803 	switch (status) {
804 	case 0:
805 		/* success */
806 		break;
807 	case -ECONNRESET:
808 	case -ENOENT:
809 	case -ESHUTDOWN:
810 		/* this urb is terminated, clean up */
811 		dev_dbg(&urb->dev->dev, "%s(): urb shutting down with status: %d\n", __func__, status);
812 		priv->flags.write_urb_in_use = 0;
813 		return;
814 	default:
815 		/* error in the urb, so we have to resubmit it */
816 		dev_dbg(&urb->dev->dev, "%s(): nonzero write bulk status received: %d\n", __func__, status);
817 		dev_dbg(&urb->dev->dev, "%s(): overflow in write\n", __func__);
818 
819 		port->write_urb->transfer_buffer_length = 1;
820 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
821 		if (result) {
822 			dev_err_console(port, "%s(): usb_submit_urb() failed,"
823 					" error %d\n", __func__, result);
824 		} else {
825 			return;
826 		}
827 	}
828 
829 	priv->flags.write_urb_in_use = 0;
830 
831 	/* schedule the interrupt urb if we are still open */
832 	dev_dbg(&port->dev, "%s(): submitting interrupt urb\n", __func__);
833 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
834 	if (result != 0) {
835 		dev_err(&port->dev, "%s(): failed submitting int urb,"
836 					" error %d\n", __func__, result);
837 	}
838 }
839 
840 module_usb_serial_driver(serial_drivers, id_table);
841 
842 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
843 MODULE_AUTHOR(OTI6858_AUTHOR);
844 MODULE_LICENSE("GPL v2");
845