xref: /linux/drivers/usb/serial/oti6858.c (revision c145211d1f9e2ef19e7b4c2b943f68366daa97af)
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 "oti6858.h"
55 
56 #define OTI6858_DESCRIPTION \
57 	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"
58 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
59 #define OTI6858_VERSION "0.1"
60 
61 static const struct usb_device_id id_table[] = {
62 	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
63 	{ }
64 };
65 
66 MODULE_DEVICE_TABLE(usb, id_table);
67 
68 static struct usb_driver oti6858_driver = {
69 	.name =		"oti6858",
70 	.probe =	usb_serial_probe,
71 	.disconnect =	usb_serial_disconnect,
72 	.id_table =	id_table,
73 	.no_dynamic_id = 	1,
74 };
75 
76 static int debug;
77 
78 
79 /* buffering code, copied from pl2303 driver */
80 #define PL2303_BUF_SIZE		1024
81 #define PL2303_TMP_BUF_SIZE	1024
82 
83 struct oti6858_buf {
84 	unsigned int	buf_size;
85 	char		*buf_buf;
86 	char		*buf_get;
87 	char		*buf_put;
88 };
89 
90 /* requests */
91 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
92 #define	OTI6858_REQ_T_GET_STATUS	0x01
93 
94 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
95 #define	OTI6858_REQ_T_SET_LINE		0x00
96 
97 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
98 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
99 
100 /* format of the control packet */
101 struct oti6858_control_pkt {
102 	__le16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
103 #define OTI6858_MAX_BAUD_RATE	3000000
104 	u8	frame_fmt;
105 #define FMT_STOP_BITS_MASK	0xc0
106 #define FMT_STOP_BITS_1		0x00
107 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
108 #define FMT_PARITY_MASK		0x38
109 #define FMT_PARITY_NONE		0x00
110 #define FMT_PARITY_ODD		0x08
111 #define FMT_PARITY_EVEN		0x18
112 #define FMT_PARITY_MARK		0x28
113 #define FMT_PARITY_SPACE	0x38
114 #define FMT_DATA_BITS_MASK	0x03
115 #define FMT_DATA_BITS_5		0x00
116 #define FMT_DATA_BITS_6		0x01
117 #define FMT_DATA_BITS_7		0x02
118 #define FMT_DATA_BITS_8		0x03
119 	u8	something;	/* always equals 0x43 */
120 	u8	control;	/* settings of flow control lines */
121 #define CONTROL_MASK		0x0c
122 #define CONTROL_DTR_HIGH	0x08
123 #define CONTROL_RTS_HIGH	0x04
124 	u8	tx_status;
125 #define	TX_BUFFER_EMPTIED	0x09
126 	u8	pin_state;
127 #define PIN_MASK		0x3f
128 #define PIN_RTS			0x20	/* output pin */
129 #define PIN_CTS			0x10	/* input pin, active low */
130 #define PIN_DSR			0x08	/* input pin, active low */
131 #define PIN_DTR			0x04	/* output pin */
132 #define PIN_RI			0x02	/* input pin, active low */
133 #define PIN_DCD			0x01	/* input pin, active low */
134 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
135 };
136 
137 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
138 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
139 	(((a)->divisor == (priv)->pending_setup.divisor) \
140 	  && ((a)->control == (priv)->pending_setup.control) \
141 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt))
142 
143 /* function prototypes */
144 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port);
145 static void oti6858_close(struct usb_serial_port *port);
146 static void oti6858_set_termios(struct tty_struct *tty,
147 			struct usb_serial_port *port, struct ktermios *old);
148 static void oti6858_init_termios(struct tty_struct *tty);
149 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
150 			unsigned int cmd, unsigned long arg);
151 static void oti6858_read_int_callback(struct urb *urb);
152 static void oti6858_read_bulk_callback(struct urb *urb);
153 static void oti6858_write_bulk_callback(struct urb *urb);
154 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
155 			const unsigned char *buf, int count);
156 static int oti6858_write_room(struct tty_struct *tty);
157 static int oti6858_chars_in_buffer(struct tty_struct *tty);
158 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file);
159 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
160 				unsigned int set, unsigned int clear);
161 static int oti6858_startup(struct usb_serial *serial);
162 static void oti6858_release(struct usb_serial *serial);
163 
164 /* functions operating on buffers */
165 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size);
166 static void oti6858_buf_free(struct oti6858_buf *pb);
167 static void oti6858_buf_clear(struct oti6858_buf *pb);
168 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb);
169 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb);
170 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
171 					unsigned int count);
172 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
173 					unsigned int count);
174 
175 
176 /* device info */
177 static struct usb_serial_driver oti6858_device = {
178 	.driver = {
179 		.owner =	THIS_MODULE,
180 		.name =		"oti6858",
181 	},
182 	.id_table =		id_table,
183 	.num_ports =		1,
184 	.open =			oti6858_open,
185 	.close =		oti6858_close,
186 	.write =		oti6858_write,
187 	.ioctl =		oti6858_ioctl,
188 	.set_termios =		oti6858_set_termios,
189 	.init_termios = 	oti6858_init_termios,
190 	.tiocmget =		oti6858_tiocmget,
191 	.tiocmset =		oti6858_tiocmset,
192 	.read_bulk_callback =	oti6858_read_bulk_callback,
193 	.read_int_callback =	oti6858_read_int_callback,
194 	.write_bulk_callback =	oti6858_write_bulk_callback,
195 	.write_room =		oti6858_write_room,
196 	.chars_in_buffer =	oti6858_chars_in_buffer,
197 	.attach =		oti6858_startup,
198 	.release =		oti6858_release,
199 };
200 
201 struct oti6858_private {
202 	spinlock_t lock;
203 
204 	struct oti6858_buf *buf;
205 	struct oti6858_control_pkt status;
206 
207 	struct {
208 		u8 read_urb_in_use;
209 		u8 write_urb_in_use;
210 	} flags;
211 	struct delayed_work delayed_write_work;
212 
213 	struct {
214 		__le16 divisor;
215 		u8 frame_fmt;
216 		u8 control;
217 	} pending_setup;
218 	u8 transient;
219 	u8 setup_done;
220 	struct delayed_work delayed_setup_work;
221 
222 	wait_queue_head_t intr_wait;
223 	struct usb_serial_port *port;   /* USB port with which associated */
224 };
225 
226 static void setup_line(struct work_struct *work)
227 {
228 	struct oti6858_private *priv = container_of(work,
229 			struct oti6858_private, delayed_setup_work.work);
230 	struct usb_serial_port *port = priv->port;
231 	struct oti6858_control_pkt *new_setup;
232 	unsigned long flags;
233 	int result;
234 
235 	dbg("%s(port = %d)", __func__, port->number);
236 
237 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
238 	if (new_setup == NULL) {
239 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
240 		/* we will try again */
241 		schedule_delayed_work(&priv->delayed_setup_work,
242 						msecs_to_jiffies(2));
243 		return;
244 	}
245 
246 	result = usb_control_msg(port->serial->dev,
247 				usb_rcvctrlpipe(port->serial->dev, 0),
248 				OTI6858_REQ_T_GET_STATUS,
249 				OTI6858_REQ_GET_STATUS,
250 				0, 0,
251 				new_setup, OTI6858_CTRL_PKT_SIZE,
252 				100);
253 
254 	if (result != OTI6858_CTRL_PKT_SIZE) {
255 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
256 		kfree(new_setup);
257 		/* we will try again */
258 		schedule_delayed_work(&priv->delayed_setup_work,
259 							msecs_to_jiffies(2));
260 		return;
261 	}
262 
263 	spin_lock_irqsave(&priv->lock, flags);
264 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
265 		new_setup->divisor = priv->pending_setup.divisor;
266 		new_setup->control = priv->pending_setup.control;
267 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
268 
269 		spin_unlock_irqrestore(&priv->lock, flags);
270 		result = usb_control_msg(port->serial->dev,
271 					usb_sndctrlpipe(port->serial->dev, 0),
272 					OTI6858_REQ_T_SET_LINE,
273 					OTI6858_REQ_SET_LINE,
274 					0, 0,
275 					new_setup, OTI6858_CTRL_PKT_SIZE,
276 					100);
277 	} else {
278 		spin_unlock_irqrestore(&priv->lock, flags);
279 		result = 0;
280 	}
281 	kfree(new_setup);
282 
283 	spin_lock_irqsave(&priv->lock, flags);
284 	if (result != OTI6858_CTRL_PKT_SIZE)
285 		priv->transient = 0;
286 	priv->setup_done = 1;
287 	spin_unlock_irqrestore(&priv->lock, flags);
288 
289 	dbg("%s(): submitting interrupt urb", __func__);
290 	port->interrupt_in_urb->dev = port->serial->dev;
291 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
292 	if (result != 0) {
293 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
294 				" with error %d\n", __func__, result);
295 	}
296 }
297 
298 void send_data(struct work_struct *work)
299 {
300 	struct oti6858_private *priv = container_of(work,
301 			struct oti6858_private, delayed_write_work.work);
302 	struct usb_serial_port *port = priv->port;
303 	int count = 0, result;
304 	unsigned long flags;
305 	u8 *allow;
306 
307 	dbg("%s(port = %d)", __func__, port->number);
308 
309 	spin_lock_irqsave(&priv->lock, flags);
310 	if (priv->flags.write_urb_in_use) {
311 		spin_unlock_irqrestore(&priv->lock, flags);
312 		schedule_delayed_work(&priv->delayed_write_work,
313 						msecs_to_jiffies(2));
314 		return;
315 	}
316 	priv->flags.write_urb_in_use = 1;
317 
318 	count = oti6858_buf_data_avail(priv->buf);
319 	spin_unlock_irqrestore(&priv->lock, flags);
320 	if (count > port->bulk_out_size)
321 		count = port->bulk_out_size;
322 
323 	if (count != 0) {
324 		allow = kmalloc(1, GFP_KERNEL);
325 		if (!allow) {
326 			dev_err(&port->dev, "%s(): kmalloc failed\n",
327 					__func__);
328 			return;
329 		}
330 		result = usb_control_msg(port->serial->dev,
331 				usb_rcvctrlpipe(port->serial->dev, 0),
332 				OTI6858_REQ_T_CHECK_TXBUFF,
333 				OTI6858_REQ_CHECK_TXBUFF,
334 				count, 0, allow, 1, 100);
335 		if (result != 1 || *allow != 0)
336 			count = 0;
337 		kfree(allow);
338 	}
339 
340 	if (count == 0) {
341 		priv->flags.write_urb_in_use = 0;
342 
343 		dbg("%s(): submitting interrupt urb", __func__);
344 		port->interrupt_in_urb->dev = port->serial->dev;
345 		result = usb_submit_urb(port->interrupt_in_urb, GFP_NOIO);
346 		if (result != 0) {
347 			dev_err(&port->dev, "%s(): usb_submit_urb() failed"
348 				" with error %d\n", __func__, result);
349 		}
350 		return;
351 	}
352 
353 	spin_lock_irqsave(&priv->lock, flags);
354 	oti6858_buf_get(priv->buf, port->write_urb->transfer_buffer, count);
355 	spin_unlock_irqrestore(&priv->lock, flags);
356 
357 	port->write_urb->transfer_buffer_length = count;
358 	port->write_urb->dev = port->serial->dev;
359 	result = usb_submit_urb(port->write_urb, GFP_NOIO);
360 	if (result != 0) {
361 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
362 			       " with error %d\n", __func__, result);
363 		priv->flags.write_urb_in_use = 0;
364 	}
365 
366 	usb_serial_port_softint(port);
367 }
368 
369 static int oti6858_startup(struct usb_serial *serial)
370 {
371 	struct usb_serial_port *port = serial->port[0];
372 	struct oti6858_private *priv;
373 	int i;
374 
375 	for (i = 0; i < serial->num_ports; ++i) {
376 		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
377 		if (!priv)
378 			break;
379 		priv->buf = oti6858_buf_alloc(PL2303_BUF_SIZE);
380 		if (priv->buf == NULL) {
381 			kfree(priv);
382 			break;
383 		}
384 
385 		spin_lock_init(&priv->lock);
386 		init_waitqueue_head(&priv->intr_wait);
387 /*		INIT_WORK(&priv->setup_work, setup_line, serial->port[i]); */
388 /*		INIT_WORK(&priv->write_work, send_data, serial->port[i]); */
389 		priv->port = port;
390 		INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
391 		INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
392 
393 		usb_set_serial_port_data(serial->port[i], priv);
394 	}
395 	if (i == serial->num_ports)
396 		return 0;
397 
398 	for (--i; i >= 0; --i) {
399 		priv = usb_get_serial_port_data(serial->port[i]);
400 		oti6858_buf_free(priv->buf);
401 		kfree(priv);
402 		usb_set_serial_port_data(serial->port[i], NULL);
403 	}
404 	return -ENOMEM;
405 }
406 
407 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
408 			const unsigned char *buf, int count)
409 {
410 	struct oti6858_private *priv = usb_get_serial_port_data(port);
411 	unsigned long flags;
412 
413 	dbg("%s(port = %d, count = %d)", __func__, port->number, count);
414 
415 	if (!count)
416 		return count;
417 
418 	spin_lock_irqsave(&priv->lock, flags);
419 	count = oti6858_buf_put(priv->buf, buf, count);
420 	spin_unlock_irqrestore(&priv->lock, flags);
421 
422 	return count;
423 }
424 
425 static int oti6858_write_room(struct tty_struct *tty)
426 {
427 	struct usb_serial_port *port = tty->driver_data;
428 	struct oti6858_private *priv = usb_get_serial_port_data(port);
429 	int room = 0;
430 	unsigned long flags;
431 
432 	dbg("%s(port = %d)", __func__, port->number);
433 
434 	spin_lock_irqsave(&priv->lock, flags);
435 	room = oti6858_buf_space_avail(priv->buf);
436 	spin_unlock_irqrestore(&priv->lock, flags);
437 
438 	return room;
439 }
440 
441 static int oti6858_chars_in_buffer(struct tty_struct *tty)
442 {
443 	struct usb_serial_port *port = tty->driver_data;
444 	struct oti6858_private *priv = usb_get_serial_port_data(port);
445 	int chars = 0;
446 	unsigned long flags;
447 
448 	dbg("%s(port = %d)", __func__, port->number);
449 
450 	spin_lock_irqsave(&priv->lock, flags);
451 	chars = oti6858_buf_data_avail(priv->buf);
452 	spin_unlock_irqrestore(&priv->lock, flags);
453 
454 	return chars;
455 }
456 
457 static void oti6858_init_termios(struct tty_struct *tty)
458 {
459 	*(tty->termios) = tty_std_termios;
460 	tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
461 	tty->termios->c_ispeed = 38400;
462 	tty->termios->c_ospeed = 38400;
463 }
464 
465 static void oti6858_set_termios(struct tty_struct *tty,
466 		struct usb_serial_port *port, struct ktermios *old_termios)
467 {
468 	struct oti6858_private *priv = usb_get_serial_port_data(port);
469 	unsigned long flags;
470 	unsigned int cflag;
471 	u8 frame_fmt, control;
472 	__le16 divisor;
473 	int br;
474 
475 	dbg("%s(port = %d)", __func__, port->number);
476 
477 	if (!tty) {
478 		dbg("%s(): no tty structures", __func__);
479 		return;
480 	}
481 
482 	cflag = tty->termios->c_cflag;
483 
484 	spin_lock_irqsave(&priv->lock, flags);
485 	divisor = priv->pending_setup.divisor;
486 	frame_fmt = priv->pending_setup.frame_fmt;
487 	control = priv->pending_setup.control;
488 	spin_unlock_irqrestore(&priv->lock, flags);
489 
490 	frame_fmt &= ~FMT_DATA_BITS_MASK;
491 	switch (cflag & CSIZE) {
492 	case CS5:
493 		frame_fmt |= FMT_DATA_BITS_5;
494 		break;
495 	case CS6:
496 		frame_fmt |= FMT_DATA_BITS_6;
497 		break;
498 	case CS7:
499 		frame_fmt |= FMT_DATA_BITS_7;
500 		break;
501 	default:
502 	case CS8:
503 		frame_fmt |= FMT_DATA_BITS_8;
504 		break;
505 	}
506 
507 	/* manufacturer claims that this device can work with baud rates
508 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
509 	 * guarantee that any other baud rate will work (especially
510 	 * the higher ones)
511 	 */
512 	br = tty_get_baud_rate(tty);
513 	if (br == 0) {
514 		divisor = 0;
515 	} else {
516 		int real_br;
517 		int new_divisor;
518 		br = min(br, OTI6858_MAX_BAUD_RATE);
519 
520 		new_divisor = (96000000 + 8 * br) / (16 * br);
521 		real_br = 96000000 / (16 * new_divisor);
522 		divisor = cpu_to_le16(new_divisor);
523 		tty_encode_baud_rate(tty, real_br, real_br);
524 	}
525 
526 	frame_fmt &= ~FMT_STOP_BITS_MASK;
527 	if ((cflag & CSTOPB) != 0)
528 		frame_fmt |= FMT_STOP_BITS_2;
529 	else
530 		frame_fmt |= FMT_STOP_BITS_1;
531 
532 	frame_fmt &= ~FMT_PARITY_MASK;
533 	if ((cflag & PARENB) != 0) {
534 		if ((cflag & PARODD) != 0)
535 			frame_fmt |= FMT_PARITY_ODD;
536 		else
537 			frame_fmt |= FMT_PARITY_EVEN;
538 	} else {
539 		frame_fmt |= FMT_PARITY_NONE;
540 	}
541 
542 	control &= ~CONTROL_MASK;
543 	if ((cflag & CRTSCTS) != 0)
544 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
545 
546 	/* change control lines if we are switching to or from B0 */
547 	/* FIXME:
548 	spin_lock_irqsave(&priv->lock, flags);
549 	control = priv->line_control;
550 	if ((cflag & CBAUD) == B0)
551 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
552 	else
553 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
554 	if (control != priv->line_control) {
555 		control = priv->line_control;
556 		spin_unlock_irqrestore(&priv->lock, flags);
557 		set_control_lines(serial->dev, control);
558 	} else {
559 		spin_unlock_irqrestore(&priv->lock, flags);
560 	}
561 	*/
562 
563 	spin_lock_irqsave(&priv->lock, flags);
564 	if (divisor != priv->pending_setup.divisor
565 			|| control != priv->pending_setup.control
566 			|| frame_fmt != priv->pending_setup.frame_fmt) {
567 		priv->pending_setup.divisor = divisor;
568 		priv->pending_setup.control = control;
569 		priv->pending_setup.frame_fmt = frame_fmt;
570 	}
571 	spin_unlock_irqrestore(&priv->lock, flags);
572 }
573 
574 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
575 {
576 	struct oti6858_private *priv = usb_get_serial_port_data(port);
577 	struct ktermios tmp_termios;
578 	struct usb_serial *serial = port->serial;
579 	struct oti6858_control_pkt *buf;
580 	unsigned long flags;
581 	int result;
582 
583 	dbg("%s(port = %d)", __func__, port->number);
584 
585 	usb_clear_halt(serial->dev, port->write_urb->pipe);
586 	usb_clear_halt(serial->dev, port->read_urb->pipe);
587 
588 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
589 	if (buf == NULL) {
590 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
591 		return -ENOMEM;
592 	}
593 
594 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
595 				OTI6858_REQ_T_GET_STATUS,
596 				OTI6858_REQ_GET_STATUS,
597 				0, 0,
598 				buf, OTI6858_CTRL_PKT_SIZE,
599 				100);
600 	if (result != OTI6858_CTRL_PKT_SIZE) {
601 		/* assume default (after power-on reset) values */
602 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
603 		buf->frame_fmt = 0x03;	/* 8N1 */
604 		buf->something = 0x43;
605 		buf->control = 0x4c;	/* DTR, RTS */
606 		buf->tx_status = 0x00;
607 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
608 		buf->rx_bytes_avail = 0x00;
609 	}
610 
611 	spin_lock_irqsave(&priv->lock, flags);
612 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
613 	priv->pending_setup.divisor = buf->divisor;
614 	priv->pending_setup.frame_fmt = buf->frame_fmt;
615 	priv->pending_setup.control = buf->control;
616 	spin_unlock_irqrestore(&priv->lock, flags);
617 	kfree(buf);
618 
619 	dbg("%s(): submitting interrupt urb", __func__);
620 	port->interrupt_in_urb->dev = serial->dev;
621 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
622 	if (result != 0) {
623 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
624 			       " with error %d\n", __func__, result);
625 		oti6858_close(port);
626 		return -EPROTO;
627 	}
628 
629 	/* setup termios */
630 	if (tty)
631 		oti6858_set_termios(tty, port, &tmp_termios);
632 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
633 	return 0;
634 }
635 
636 static void oti6858_close(struct usb_serial_port *port)
637 {
638 	struct oti6858_private *priv = usb_get_serial_port_data(port);
639 	unsigned long flags;
640 
641 	dbg("%s(port = %d)", __func__, port->number);
642 
643 	spin_lock_irqsave(&priv->lock, flags);
644 	/* clear out any remaining data in the buffer */
645 	oti6858_buf_clear(priv->buf);
646 	spin_unlock_irqrestore(&priv->lock, flags);
647 
648 	dbg("%s(): after buf_clear()", __func__);
649 
650 	/* cancel scheduled setup */
651 	cancel_delayed_work(&priv->delayed_setup_work);
652 	cancel_delayed_work(&priv->delayed_write_work);
653 	flush_scheduled_work();
654 
655 	/* shutdown our urbs */
656 	dbg("%s(): shutting down urbs", __func__);
657 	usb_kill_urb(port->write_urb);
658 	usb_kill_urb(port->read_urb);
659 	usb_kill_urb(port->interrupt_in_urb);
660 }
661 
662 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
663 				unsigned int set, unsigned int clear)
664 {
665 	struct usb_serial_port *port = tty->driver_data;
666 	struct oti6858_private *priv = usb_get_serial_port_data(port);
667 	unsigned long flags;
668 	u8 control;
669 
670 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
671 				__func__, port->number, set, clear);
672 
673 	if (!usb_get_intfdata(port->serial->interface))
674 		return -ENODEV;
675 
676 	/* FIXME: check if this is correct (active high/low) */
677 	spin_lock_irqsave(&priv->lock, flags);
678 	control = priv->pending_setup.control;
679 	if ((set & TIOCM_RTS) != 0)
680 		control |= CONTROL_RTS_HIGH;
681 	if ((set & TIOCM_DTR) != 0)
682 		control |= CONTROL_DTR_HIGH;
683 	if ((clear & TIOCM_RTS) != 0)
684 		control &= ~CONTROL_RTS_HIGH;
685 	if ((clear & TIOCM_DTR) != 0)
686 		control &= ~CONTROL_DTR_HIGH;
687 
688 	if (control != priv->pending_setup.control)
689 		priv->pending_setup.control = control;
690 
691 	spin_unlock_irqrestore(&priv->lock, flags);
692 	return 0;
693 }
694 
695 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file)
696 {
697 	struct usb_serial_port *port = tty->driver_data;
698 	struct oti6858_private *priv = usb_get_serial_port_data(port);
699 	unsigned long flags;
700 	unsigned pin_state;
701 	unsigned result = 0;
702 
703 	dbg("%s(port = %d)", __func__, port->number);
704 
705 	if (!usb_get_intfdata(port->serial->interface))
706 		return -ENODEV;
707 
708 	spin_lock_irqsave(&priv->lock, flags);
709 	pin_state = priv->status.pin_state & PIN_MASK;
710 	spin_unlock_irqrestore(&priv->lock, flags);
711 
712 	/* FIXME: check if this is correct (active high/low) */
713 	if ((pin_state & PIN_RTS) != 0)
714 		result |= TIOCM_RTS;
715 	if ((pin_state & PIN_CTS) != 0)
716 		result |= TIOCM_CTS;
717 	if ((pin_state & PIN_DSR) != 0)
718 		result |= TIOCM_DSR;
719 	if ((pin_state & PIN_DTR) != 0)
720 		result |= TIOCM_DTR;
721 	if ((pin_state & PIN_RI) != 0)
722 		result |= TIOCM_RI;
723 	if ((pin_state & PIN_DCD) != 0)
724 		result |= TIOCM_CD;
725 
726 	dbg("%s() = 0x%08x", __func__, result);
727 
728 	return result;
729 }
730 
731 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
732 {
733 	struct oti6858_private *priv = usb_get_serial_port_data(port);
734 	unsigned long flags;
735 	unsigned int prev, status;
736 	unsigned int changed;
737 
738 	spin_lock_irqsave(&priv->lock, flags);
739 	prev = priv->status.pin_state;
740 	spin_unlock_irqrestore(&priv->lock, flags);
741 
742 	while (1) {
743 		wait_event_interruptible(priv->intr_wait,
744 					priv->status.pin_state != prev);
745 		if (signal_pending(current))
746 			return -ERESTARTSYS;
747 
748 		spin_lock_irqsave(&priv->lock, flags);
749 		status = priv->status.pin_state & PIN_MASK;
750 		spin_unlock_irqrestore(&priv->lock, flags);
751 
752 		changed = prev ^ status;
753 		/* FIXME: check if this is correct (active high/low) */
754 		if (((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
755 		    ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
756 		    ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
757 		    ((arg & TIOCM_CTS) && (changed & PIN_CTS)))
758 			return 0;
759 		prev = status;
760 	}
761 
762 	/* NOTREACHED */
763 	return 0;
764 }
765 
766 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
767 			unsigned int cmd, unsigned long arg)
768 {
769 	struct usb_serial_port *port = tty->driver_data;
770 
771 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
772 				__func__, port->number, cmd, arg);
773 
774 	switch (cmd) {
775 	case TIOCMIWAIT:
776 		dbg("%s(): TIOCMIWAIT", __func__);
777 		return wait_modem_info(port, arg);
778 	default:
779 		dbg("%s(): 0x%04x not supported", __func__, cmd);
780 		break;
781 	}
782 	return -ENOIOCTLCMD;
783 }
784 
785 
786 static void oti6858_release(struct usb_serial *serial)
787 {
788 	struct oti6858_private *priv;
789 	int i;
790 
791 	dbg("%s()", __func__);
792 
793 	for (i = 0; i < serial->num_ports; ++i) {
794 		priv = usb_get_serial_port_data(serial->port[i]);
795 		if (priv) {
796 			oti6858_buf_free(priv->buf);
797 			kfree(priv);
798 		}
799 	}
800 }
801 
802 static void oti6858_read_int_callback(struct urb *urb)
803 {
804 	struct usb_serial_port *port =  urb->context;
805 	struct oti6858_private *priv = usb_get_serial_port_data(port);
806 	int transient = 0, can_recv = 0, resubmit = 1;
807 	int status = urb->status;
808 
809 	dbg("%s(port = %d, status = %d)",
810 				__func__, port->number, status);
811 
812 	switch (status) {
813 	case 0:
814 		/* success */
815 		break;
816 	case -ECONNRESET:
817 	case -ENOENT:
818 	case -ESHUTDOWN:
819 		/* this urb is terminated, clean up */
820 		dbg("%s(): urb shutting down with status: %d",
821 					__func__, status);
822 		return;
823 	default:
824 		dbg("%s(): nonzero urb status received: %d",
825 					__func__, status);
826 		break;
827 	}
828 
829 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
830 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
831 		unsigned long flags;
832 
833 		spin_lock_irqsave(&priv->lock, flags);
834 
835 		if (!priv->transient) {
836 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
837 				if (xs->rx_bytes_avail == 0) {
838 					priv->transient = 4;
839 					priv->setup_done = 0;
840 					resubmit = 0;
841 					dbg("%s(): scheduling setup_line()",
842 					    __func__);
843 					schedule_delayed_work(&priv->delayed_setup_work, 0);
844 				}
845 			}
846 		} else {
847 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
848 				priv->transient = 0;
849 			} else if (!priv->setup_done) {
850 				resubmit = 0;
851 			} else if (--priv->transient == 0) {
852 				if (xs->rx_bytes_avail == 0) {
853 					priv->transient = 4;
854 					priv->setup_done = 0;
855 					resubmit = 0;
856 					dbg("%s(): scheduling setup_line()",
857 					    __func__);
858 					schedule_delayed_work(&priv->delayed_setup_work, 0);
859 				}
860 			}
861 		}
862 
863 		if (!priv->transient) {
864 			if (xs->pin_state != priv->status.pin_state)
865 				wake_up_interruptible(&priv->intr_wait);
866 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
867 		}
868 
869 		if (!priv->transient && xs->rx_bytes_avail != 0) {
870 			can_recv = xs->rx_bytes_avail;
871 			priv->flags.read_urb_in_use = 1;
872 		}
873 
874 		transient = priv->transient;
875 		spin_unlock_irqrestore(&priv->lock, flags);
876 	}
877 
878 	if (can_recv) {
879 		int result;
880 
881 		port->read_urb->dev = port->serial->dev;
882 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
883 		if (result != 0) {
884 			priv->flags.read_urb_in_use = 0;
885 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
886 					" error %d\n", __func__, result);
887 		} else {
888 			resubmit = 0;
889 		}
890 	} else if (!transient) {
891 		unsigned long flags;
892 
893 		spin_lock_irqsave(&priv->lock, flags);
894 		if (priv->flags.write_urb_in_use == 0
895 				&& oti6858_buf_data_avail(priv->buf) != 0) {
896 			schedule_delayed_work(&priv->delayed_write_work, 0);
897 			resubmit = 0;
898 		}
899 		spin_unlock_irqrestore(&priv->lock, flags);
900 	}
901 
902 	if (resubmit) {
903 		int result;
904 
905 /*		dbg("%s(): submitting interrupt urb", __func__); */
906 		urb->dev = port->serial->dev;
907 		result = usb_submit_urb(urb, GFP_ATOMIC);
908 		if (result != 0) {
909 			dev_err(&urb->dev->dev,
910 					"%s(): usb_submit_urb() failed with"
911 					" error %d\n", __func__, result);
912 		}
913 	}
914 }
915 
916 static void oti6858_read_bulk_callback(struct urb *urb)
917 {
918 	struct usb_serial_port *port =  urb->context;
919 	struct oti6858_private *priv = usb_get_serial_port_data(port);
920 	struct tty_struct *tty;
921 	unsigned char *data = urb->transfer_buffer;
922 	unsigned long flags;
923 	int status = urb->status;
924 	int result;
925 
926 	dbg("%s(port = %d, status = %d)",
927 				__func__, port->number, status);
928 
929 	spin_lock_irqsave(&priv->lock, flags);
930 	priv->flags.read_urb_in_use = 0;
931 	spin_unlock_irqrestore(&priv->lock, flags);
932 
933 	if (status != 0) {
934 		/*
935 		if (status == -EPROTO) {
936 			* PL2303 mysteriously fails with -EPROTO reschedule
937 			   the read *
938 			dbg("%s - caught -EPROTO, resubmitting the urb",
939 								__func__);
940 			result = usb_submit_urb(urb, GFP_ATOMIC);
941 			if (result)
942 				dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __func__, result);
943 			return;
944 		}
945 		*/
946 		dbg("%s(): unable to handle the error, exiting", __func__);
947 		return;
948 	}
949 
950 	tty = tty_port_tty_get(&port->port);
951 	if (tty != NULL && urb->actual_length > 0) {
952 		tty_insert_flip_string(tty, data, urb->actual_length);
953 		tty_flip_buffer_push(tty);
954 	}
955 	tty_kref_put(tty);
956 
957 	/* schedule the interrupt urb */
958 	port->interrupt_in_urb->dev = port->serial->dev;
959 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
960 	if (result != 0 && result != -EPERM) {
961 		dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
962 				" error %d\n", __func__, result);
963 	}
964 }
965 
966 static void oti6858_write_bulk_callback(struct urb *urb)
967 {
968 	struct usb_serial_port *port =  urb->context;
969 	struct oti6858_private *priv = usb_get_serial_port_data(port);
970 	int status = urb->status;
971 	int result;
972 
973 	dbg("%s(port = %d, status = %d)",
974 				__func__, port->number, status);
975 
976 	switch (status) {
977 	case 0:
978 		/* success */
979 		break;
980 	case -ECONNRESET:
981 	case -ENOENT:
982 	case -ESHUTDOWN:
983 		/* this urb is terminated, clean up */
984 		dbg("%s(): urb shutting down with status: %d",
985 					__func__, status);
986 		priv->flags.write_urb_in_use = 0;
987 		return;
988 	default:
989 		/* error in the urb, so we have to resubmit it */
990 		dbg("%s(): nonzero write bulk status received: %d",
991 					__func__, status);
992 		dbg("%s(): overflow in write", __func__);
993 
994 		port->write_urb->transfer_buffer_length = 1;
995 		port->write_urb->dev = port->serial->dev;
996 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
997 		if (result) {
998 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
999 					" error %d\n", __func__, result);
1000 		} else {
1001 			return;
1002 		}
1003 	}
1004 
1005 	priv->flags.write_urb_in_use = 0;
1006 
1007 	/* schedule the interrupt urb if we are still open */
1008 	port->interrupt_in_urb->dev = port->serial->dev;
1009 	dbg("%s(): submitting interrupt urb", __func__);
1010 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1011 	if (result != 0) {
1012 		dev_err(&port->dev, "%s(): failed submitting int urb,"
1013 					" error %d\n", __func__, result);
1014 	}
1015 }
1016 
1017 
1018 /*
1019  * oti6858_buf_alloc
1020  *
1021  * Allocate a circular buffer and all associated memory.
1022  */
1023 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
1024 {
1025 	struct oti6858_buf *pb;
1026 
1027 	if (size == 0)
1028 		return NULL;
1029 
1030 	pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
1031 	if (pb == NULL)
1032 		return NULL;
1033 
1034 	pb->buf_buf = kmalloc(size, GFP_KERNEL);
1035 	if (pb->buf_buf == NULL) {
1036 		kfree(pb);
1037 		return NULL;
1038 	}
1039 
1040 	pb->buf_size = size;
1041 	pb->buf_get = pb->buf_put = pb->buf_buf;
1042 
1043 	return pb;
1044 }
1045 
1046 /*
1047  * oti6858_buf_free
1048  *
1049  * Free the buffer and all associated memory.
1050  */
1051 static void oti6858_buf_free(struct oti6858_buf *pb)
1052 {
1053 	if (pb) {
1054 		kfree(pb->buf_buf);
1055 		kfree(pb);
1056 	}
1057 }
1058 
1059 /*
1060  * oti6858_buf_clear
1061  *
1062  * Clear out all data in the circular buffer.
1063  */
1064 static void oti6858_buf_clear(struct oti6858_buf *pb)
1065 {
1066 	if (pb != NULL) {
1067 		/* equivalent to a get of all data available */
1068 		pb->buf_get = pb->buf_put;
1069 	}
1070 }
1071 
1072 /*
1073  * oti6858_buf_data_avail
1074  *
1075  * Return the number of bytes of data available in the circular
1076  * buffer.
1077  */
1078 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
1079 {
1080 	if (pb == NULL)
1081 		return 0;
1082 	return (pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size;
1083 }
1084 
1085 /*
1086  * oti6858_buf_space_avail
1087  *
1088  * Return the number of bytes of space available in the circular
1089  * buffer.
1090  */
1091 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
1092 {
1093 	if (pb == NULL)
1094 		return 0;
1095 	return (pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size;
1096 }
1097 
1098 /*
1099  * oti6858_buf_put
1100  *
1101  * Copy data data from a user buffer and put it into the circular buffer.
1102  * Restrict to the amount of space available.
1103  *
1104  * Return the number of bytes copied.
1105  */
1106 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
1107 					unsigned int count)
1108 {
1109 	unsigned int len;
1110 
1111 	if (pb == NULL)
1112 		return 0;
1113 
1114 	len  = oti6858_buf_space_avail(pb);
1115 	if (count > len)
1116 		count = len;
1117 
1118 	if (count == 0)
1119 		return 0;
1120 
1121 	len = pb->buf_buf + pb->buf_size - pb->buf_put;
1122 	if (count > len) {
1123 		memcpy(pb->buf_put, buf, len);
1124 		memcpy(pb->buf_buf, buf+len, count - len);
1125 		pb->buf_put = pb->buf_buf + count - len;
1126 	} else {
1127 		memcpy(pb->buf_put, buf, count);
1128 		if (count < len)
1129 			pb->buf_put += count;
1130 		else /* count == len */
1131 			pb->buf_put = pb->buf_buf;
1132 	}
1133 
1134 	return count;
1135 }
1136 
1137 /*
1138  * oti6858_buf_get
1139  *
1140  * Get data from the circular buffer and copy to the given buffer.
1141  * Restrict to the amount of data available.
1142  *
1143  * Return the number of bytes copied.
1144  */
1145 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
1146 					unsigned int count)
1147 {
1148 	unsigned int len;
1149 
1150 	if (pb == NULL)
1151 		return 0;
1152 
1153 	len = oti6858_buf_data_avail(pb);
1154 	if (count > len)
1155 		count = len;
1156 
1157 	if (count == 0)
1158 		return 0;
1159 
1160 	len = pb->buf_buf + pb->buf_size - pb->buf_get;
1161 	if (count > len) {
1162 		memcpy(buf, pb->buf_get, len);
1163 		memcpy(buf+len, pb->buf_buf, count - len);
1164 		pb->buf_get = pb->buf_buf + count - len;
1165 	} else {
1166 		memcpy(buf, pb->buf_get, count);
1167 		if (count < len)
1168 			pb->buf_get += count;
1169 		else /* count == len */
1170 			pb->buf_get = pb->buf_buf;
1171 	}
1172 
1173 	return count;
1174 }
1175 
1176 /* module description and (de)initialization */
1177 
1178 static int __init oti6858_init(void)
1179 {
1180 	int retval;
1181 
1182 	retval = usb_serial_register(&oti6858_device);
1183 	if (retval == 0) {
1184 		retval = usb_register(&oti6858_driver);
1185 		if (retval)
1186 			usb_serial_deregister(&oti6858_device);
1187 	}
1188 	return retval;
1189 }
1190 
1191 static void __exit oti6858_exit(void)
1192 {
1193 	usb_deregister(&oti6858_driver);
1194 	usb_serial_deregister(&oti6858_device);
1195 }
1196 
1197 module_init(oti6858_init);
1198 module_exit(oti6858_exit);
1199 
1200 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1201 MODULE_AUTHOR(OTI6858_AUTHOR);
1202 MODULE_VERSION(OTI6858_VERSION);
1203 MODULE_LICENSE("GPL");
1204 
1205 module_param(debug, bool, S_IRUGO | S_IWUSR);
1206 MODULE_PARM_DESC(debug, "enable debug output");
1207 
1208