xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision fd589a8f)
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 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_ATOMIC);
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 	unsigned char 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 		result = usb_control_msg(port->serial->dev,
325 				usb_rcvctrlpipe(port->serial->dev, 0),
326 				OTI6858_REQ_T_CHECK_TXBUFF,
327 				OTI6858_REQ_CHECK_TXBUFF,
328 				count, 0, &allow, 1, 100);
329 		if (result != 1 || allow != 0)
330 			count = 0;
331 	}
332 
333 	if (count == 0) {
334 		priv->flags.write_urb_in_use = 0;
335 
336 		dbg("%s(): submitting interrupt urb", __func__);
337 		port->interrupt_in_urb->dev = port->serial->dev;
338 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
339 		if (result != 0) {
340 			dev_err(&port->dev, "%s(): usb_submit_urb() failed"
341 				" with error %d\n", __func__, result);
342 		}
343 		return;
344 	}
345 
346 	spin_lock_irqsave(&priv->lock, flags);
347 	oti6858_buf_get(priv->buf, port->write_urb->transfer_buffer, count);
348 	spin_unlock_irqrestore(&priv->lock, flags);
349 
350 	port->write_urb->transfer_buffer_length = count;
351 	port->write_urb->dev = port->serial->dev;
352 	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
353 	if (result != 0) {
354 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
355 			       " with error %d\n", __func__, result);
356 		priv->flags.write_urb_in_use = 0;
357 	}
358 
359 	usb_serial_port_softint(port);
360 }
361 
362 static int oti6858_startup(struct usb_serial *serial)
363 {
364 	struct usb_serial_port *port = serial->port[0];
365 	struct oti6858_private *priv;
366 	int i;
367 
368 	for (i = 0; i < serial->num_ports; ++i) {
369 		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
370 		if (!priv)
371 			break;
372 		priv->buf = oti6858_buf_alloc(PL2303_BUF_SIZE);
373 		if (priv->buf == NULL) {
374 			kfree(priv);
375 			break;
376 		}
377 
378 		spin_lock_init(&priv->lock);
379 		init_waitqueue_head(&priv->intr_wait);
380 /*		INIT_WORK(&priv->setup_work, setup_line, serial->port[i]); */
381 /*		INIT_WORK(&priv->write_work, send_data, serial->port[i]); */
382 		priv->port = port;
383 		INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
384 		INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
385 
386 		usb_set_serial_port_data(serial->port[i], priv);
387 	}
388 	if (i == serial->num_ports)
389 		return 0;
390 
391 	for (--i; i >= 0; --i) {
392 		priv = usb_get_serial_port_data(serial->port[i]);
393 		oti6858_buf_free(priv->buf);
394 		kfree(priv);
395 		usb_set_serial_port_data(serial->port[i], NULL);
396 	}
397 	return -ENOMEM;
398 }
399 
400 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
401 			const unsigned char *buf, int count)
402 {
403 	struct oti6858_private *priv = usb_get_serial_port_data(port);
404 	unsigned long flags;
405 
406 	dbg("%s(port = %d, count = %d)", __func__, port->number, count);
407 
408 	if (!count)
409 		return count;
410 
411 	spin_lock_irqsave(&priv->lock, flags);
412 	count = oti6858_buf_put(priv->buf, buf, count);
413 	spin_unlock_irqrestore(&priv->lock, flags);
414 
415 	return count;
416 }
417 
418 static int oti6858_write_room(struct tty_struct *tty)
419 {
420 	struct usb_serial_port *port = tty->driver_data;
421 	struct oti6858_private *priv = usb_get_serial_port_data(port);
422 	int room = 0;
423 	unsigned long flags;
424 
425 	dbg("%s(port = %d)", __func__, port->number);
426 
427 	spin_lock_irqsave(&priv->lock, flags);
428 	room = oti6858_buf_space_avail(priv->buf);
429 	spin_unlock_irqrestore(&priv->lock, flags);
430 
431 	return room;
432 }
433 
434 static int oti6858_chars_in_buffer(struct tty_struct *tty)
435 {
436 	struct usb_serial_port *port = tty->driver_data;
437 	struct oti6858_private *priv = usb_get_serial_port_data(port);
438 	int chars = 0;
439 	unsigned long flags;
440 
441 	dbg("%s(port = %d)", __func__, port->number);
442 
443 	spin_lock_irqsave(&priv->lock, flags);
444 	chars = oti6858_buf_data_avail(priv->buf);
445 	spin_unlock_irqrestore(&priv->lock, flags);
446 
447 	return chars;
448 }
449 
450 static void oti6858_init_termios(struct tty_struct *tty)
451 {
452 	*(tty->termios) = tty_std_termios;
453 	tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
454 	tty->termios->c_ispeed = 38400;
455 	tty->termios->c_ospeed = 38400;
456 }
457 
458 static void oti6858_set_termios(struct tty_struct *tty,
459 		struct usb_serial_port *port, struct ktermios *old_termios)
460 {
461 	struct oti6858_private *priv = usb_get_serial_port_data(port);
462 	unsigned long flags;
463 	unsigned int cflag;
464 	u8 frame_fmt, control;
465 	__le16 divisor;
466 	int br;
467 
468 	dbg("%s(port = %d)", __func__, port->number);
469 
470 	if (!tty) {
471 		dbg("%s(): no tty structures", __func__);
472 		return;
473 	}
474 
475 	cflag = tty->termios->c_cflag;
476 
477 	spin_lock_irqsave(&priv->lock, flags);
478 	divisor = priv->pending_setup.divisor;
479 	frame_fmt = priv->pending_setup.frame_fmt;
480 	control = priv->pending_setup.control;
481 	spin_unlock_irqrestore(&priv->lock, flags);
482 
483 	frame_fmt &= ~FMT_DATA_BITS_MASK;
484 	switch (cflag & CSIZE) {
485 	case CS5:
486 		frame_fmt |= FMT_DATA_BITS_5;
487 		break;
488 	case CS6:
489 		frame_fmt |= FMT_DATA_BITS_6;
490 		break;
491 	case CS7:
492 		frame_fmt |= FMT_DATA_BITS_7;
493 		break;
494 	default:
495 	case CS8:
496 		frame_fmt |= FMT_DATA_BITS_8;
497 		break;
498 	}
499 
500 	/* manufacturer claims that this device can work with baud rates
501 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
502 	 * guarantee that any other baud rate will work (especially
503 	 * the higher ones)
504 	 */
505 	br = tty_get_baud_rate(tty);
506 	if (br == 0) {
507 		divisor = 0;
508 	} else {
509 		int real_br;
510 		int new_divisor;
511 		br = min(br, OTI6858_MAX_BAUD_RATE);
512 
513 		new_divisor = (96000000 + 8 * br) / (16 * br);
514 		real_br = 96000000 / (16 * new_divisor);
515 		divisor = cpu_to_le16(new_divisor);
516 		tty_encode_baud_rate(tty, real_br, real_br);
517 	}
518 
519 	frame_fmt &= ~FMT_STOP_BITS_MASK;
520 	if ((cflag & CSTOPB) != 0)
521 		frame_fmt |= FMT_STOP_BITS_2;
522 	else
523 		frame_fmt |= FMT_STOP_BITS_1;
524 
525 	frame_fmt &= ~FMT_PARITY_MASK;
526 	if ((cflag & PARENB) != 0) {
527 		if ((cflag & PARODD) != 0)
528 			frame_fmt |= FMT_PARITY_ODD;
529 		else
530 			frame_fmt |= FMT_PARITY_EVEN;
531 	} else {
532 		frame_fmt |= FMT_PARITY_NONE;
533 	}
534 
535 	control &= ~CONTROL_MASK;
536 	if ((cflag & CRTSCTS) != 0)
537 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
538 
539 	/* change control lines if we are switching to or from B0 */
540 	/* FIXME:
541 	spin_lock_irqsave(&priv->lock, flags);
542 	control = priv->line_control;
543 	if ((cflag & CBAUD) == B0)
544 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
545 	else
546 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
547 	if (control != priv->line_control) {
548 		control = priv->line_control;
549 		spin_unlock_irqrestore(&priv->lock, flags);
550 		set_control_lines(serial->dev, control);
551 	} else {
552 		spin_unlock_irqrestore(&priv->lock, flags);
553 	}
554 	*/
555 
556 	spin_lock_irqsave(&priv->lock, flags);
557 	if (divisor != priv->pending_setup.divisor
558 			|| control != priv->pending_setup.control
559 			|| frame_fmt != priv->pending_setup.frame_fmt) {
560 		priv->pending_setup.divisor = divisor;
561 		priv->pending_setup.control = control;
562 		priv->pending_setup.frame_fmt = frame_fmt;
563 	}
564 	spin_unlock_irqrestore(&priv->lock, flags);
565 }
566 
567 static int oti6858_open(struct tty_struct *tty, struct usb_serial_port *port)
568 {
569 	struct oti6858_private *priv = usb_get_serial_port_data(port);
570 	struct ktermios tmp_termios;
571 	struct usb_serial *serial = port->serial;
572 	struct oti6858_control_pkt *buf;
573 	unsigned long flags;
574 	int result;
575 
576 	dbg("%s(port = %d)", __func__, port->number);
577 
578 	usb_clear_halt(serial->dev, port->write_urb->pipe);
579 	usb_clear_halt(serial->dev, port->read_urb->pipe);
580 
581 	if (port->port.count != 1)
582 		return 0;
583 
584 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
585 	if (buf == NULL) {
586 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
587 		return -ENOMEM;
588 	}
589 
590 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
591 				OTI6858_REQ_T_GET_STATUS,
592 				OTI6858_REQ_GET_STATUS,
593 				0, 0,
594 				buf, OTI6858_CTRL_PKT_SIZE,
595 				100);
596 	if (result != OTI6858_CTRL_PKT_SIZE) {
597 		/* assume default (after power-on reset) values */
598 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
599 		buf->frame_fmt = 0x03;	/* 8N1 */
600 		buf->something = 0x43;
601 		buf->control = 0x4c;	/* DTR, RTS */
602 		buf->tx_status = 0x00;
603 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
604 		buf->rx_bytes_avail = 0x00;
605 	}
606 
607 	spin_lock_irqsave(&priv->lock, flags);
608 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
609 	priv->pending_setup.divisor = buf->divisor;
610 	priv->pending_setup.frame_fmt = buf->frame_fmt;
611 	priv->pending_setup.control = buf->control;
612 	spin_unlock_irqrestore(&priv->lock, flags);
613 	kfree(buf);
614 
615 	dbg("%s(): submitting interrupt urb", __func__);
616 	port->interrupt_in_urb->dev = serial->dev;
617 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
618 	if (result != 0) {
619 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
620 			       " with error %d\n", __func__, result);
621 		oti6858_close(port);
622 		return -EPROTO;
623 	}
624 
625 	/* setup termios */
626 	if (tty)
627 		oti6858_set_termios(tty, port, &tmp_termios);
628 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
629 	return 0;
630 }
631 
632 static void oti6858_close(struct usb_serial_port *port)
633 {
634 	struct oti6858_private *priv = usb_get_serial_port_data(port);
635 	unsigned long flags;
636 
637 	dbg("%s(port = %d)", __func__, port->number);
638 
639 	spin_lock_irqsave(&priv->lock, flags);
640 	/* clear out any remaining data in the buffer */
641 	oti6858_buf_clear(priv->buf);
642 	spin_unlock_irqrestore(&priv->lock, flags);
643 
644 	dbg("%s(): after buf_clear()", __func__);
645 
646 	/* cancel scheduled setup */
647 	cancel_delayed_work(&priv->delayed_setup_work);
648 	cancel_delayed_work(&priv->delayed_write_work);
649 	flush_scheduled_work();
650 
651 	/* shutdown our urbs */
652 	dbg("%s(): shutting down urbs", __func__);
653 	usb_kill_urb(port->write_urb);
654 	usb_kill_urb(port->read_urb);
655 	usb_kill_urb(port->interrupt_in_urb);
656 }
657 
658 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
659 				unsigned int set, unsigned int clear)
660 {
661 	struct usb_serial_port *port = tty->driver_data;
662 	struct oti6858_private *priv = usb_get_serial_port_data(port);
663 	unsigned long flags;
664 	u8 control;
665 
666 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
667 				__func__, port->number, set, clear);
668 
669 	if (!usb_get_intfdata(port->serial->interface))
670 		return -ENODEV;
671 
672 	/* FIXME: check if this is correct (active high/low) */
673 	spin_lock_irqsave(&priv->lock, flags);
674 	control = priv->pending_setup.control;
675 	if ((set & TIOCM_RTS) != 0)
676 		control |= CONTROL_RTS_HIGH;
677 	if ((set & TIOCM_DTR) != 0)
678 		control |= CONTROL_DTR_HIGH;
679 	if ((clear & TIOCM_RTS) != 0)
680 		control &= ~CONTROL_RTS_HIGH;
681 	if ((clear & TIOCM_DTR) != 0)
682 		control &= ~CONTROL_DTR_HIGH;
683 
684 	if (control != priv->pending_setup.control)
685 		priv->pending_setup.control = control;
686 
687 	spin_unlock_irqrestore(&priv->lock, flags);
688 	return 0;
689 }
690 
691 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file)
692 {
693 	struct usb_serial_port *port = tty->driver_data;
694 	struct oti6858_private *priv = usb_get_serial_port_data(port);
695 	unsigned long flags;
696 	unsigned pin_state;
697 	unsigned result = 0;
698 
699 	dbg("%s(port = %d)", __func__, port->number);
700 
701 	if (!usb_get_intfdata(port->serial->interface))
702 		return -ENODEV;
703 
704 	spin_lock_irqsave(&priv->lock, flags);
705 	pin_state = priv->status.pin_state & PIN_MASK;
706 	spin_unlock_irqrestore(&priv->lock, flags);
707 
708 	/* FIXME: check if this is correct (active high/low) */
709 	if ((pin_state & PIN_RTS) != 0)
710 		result |= TIOCM_RTS;
711 	if ((pin_state & PIN_CTS) != 0)
712 		result |= TIOCM_CTS;
713 	if ((pin_state & PIN_DSR) != 0)
714 		result |= TIOCM_DSR;
715 	if ((pin_state & PIN_DTR) != 0)
716 		result |= TIOCM_DTR;
717 	if ((pin_state & PIN_RI) != 0)
718 		result |= TIOCM_RI;
719 	if ((pin_state & PIN_DCD) != 0)
720 		result |= TIOCM_CD;
721 
722 	dbg("%s() = 0x%08x", __func__, result);
723 
724 	return result;
725 }
726 
727 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
728 {
729 	struct oti6858_private *priv = usb_get_serial_port_data(port);
730 	unsigned long flags;
731 	unsigned int prev, status;
732 	unsigned int changed;
733 
734 	spin_lock_irqsave(&priv->lock, flags);
735 	prev = priv->status.pin_state;
736 	spin_unlock_irqrestore(&priv->lock, flags);
737 
738 	while (1) {
739 		wait_event_interruptible(priv->intr_wait,
740 					priv->status.pin_state != prev);
741 		if (signal_pending(current))
742 			return -ERESTARTSYS;
743 
744 		spin_lock_irqsave(&priv->lock, flags);
745 		status = priv->status.pin_state & PIN_MASK;
746 		spin_unlock_irqrestore(&priv->lock, flags);
747 
748 		changed = prev ^ status;
749 		/* FIXME: check if this is correct (active high/low) */
750 		if (((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
751 		    ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
752 		    ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
753 		    ((arg & TIOCM_CTS) && (changed & PIN_CTS)))
754 			return 0;
755 		prev = status;
756 	}
757 
758 	/* NOTREACHED */
759 	return 0;
760 }
761 
762 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
763 			unsigned int cmd, unsigned long arg)
764 {
765 	struct usb_serial_port *port = tty->driver_data;
766 
767 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
768 				__func__, port->number, cmd, arg);
769 
770 	switch (cmd) {
771 	case TIOCMIWAIT:
772 		dbg("%s(): TIOCMIWAIT", __func__);
773 		return wait_modem_info(port, arg);
774 	default:
775 		dbg("%s(): 0x%04x not supported", __func__, cmd);
776 		break;
777 	}
778 	return -ENOIOCTLCMD;
779 }
780 
781 
782 static void oti6858_release(struct usb_serial *serial)
783 {
784 	struct oti6858_private *priv;
785 	int i;
786 
787 	dbg("%s()", __func__);
788 
789 	for (i = 0; i < serial->num_ports; ++i) {
790 		priv = usb_get_serial_port_data(serial->port[i]);
791 		if (priv) {
792 			oti6858_buf_free(priv->buf);
793 			kfree(priv);
794 		}
795 	}
796 }
797 
798 static void oti6858_read_int_callback(struct urb *urb)
799 {
800 	struct usb_serial_port *port =  urb->context;
801 	struct oti6858_private *priv = usb_get_serial_port_data(port);
802 	int transient = 0, can_recv = 0, resubmit = 1;
803 	int status = urb->status;
804 
805 	dbg("%s(port = %d, status = %d)",
806 				__func__, port->number, status);
807 
808 	switch (status) {
809 	case 0:
810 		/* success */
811 		break;
812 	case -ECONNRESET:
813 	case -ENOENT:
814 	case -ESHUTDOWN:
815 		/* this urb is terminated, clean up */
816 		dbg("%s(): urb shutting down with status: %d",
817 					__func__, status);
818 		return;
819 	default:
820 		dbg("%s(): nonzero urb status received: %d",
821 					__func__, status);
822 		break;
823 	}
824 
825 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
826 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
827 		unsigned long flags;
828 
829 		spin_lock_irqsave(&priv->lock, flags);
830 
831 		if (!priv->transient) {
832 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
833 				if (xs->rx_bytes_avail == 0) {
834 					priv->transient = 4;
835 					priv->setup_done = 0;
836 					resubmit = 0;
837 					dbg("%s(): scheduling setup_line()",
838 					    __func__);
839 					schedule_delayed_work(&priv->delayed_setup_work, 0);
840 				}
841 			}
842 		} else {
843 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
844 				priv->transient = 0;
845 			} else if (!priv->setup_done) {
846 				resubmit = 0;
847 			} else if (--priv->transient == 0) {
848 				if (xs->rx_bytes_avail == 0) {
849 					priv->transient = 4;
850 					priv->setup_done = 0;
851 					resubmit = 0;
852 					dbg("%s(): scheduling setup_line()",
853 					    __func__);
854 					schedule_delayed_work(&priv->delayed_setup_work, 0);
855 				}
856 			}
857 		}
858 
859 		if (!priv->transient) {
860 			if (xs->pin_state != priv->status.pin_state)
861 				wake_up_interruptible(&priv->intr_wait);
862 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
863 		}
864 
865 		if (!priv->transient && xs->rx_bytes_avail != 0) {
866 			can_recv = xs->rx_bytes_avail;
867 			priv->flags.read_urb_in_use = 1;
868 		}
869 
870 		transient = priv->transient;
871 		spin_unlock_irqrestore(&priv->lock, flags);
872 	}
873 
874 	if (can_recv) {
875 		int result;
876 
877 		port->read_urb->dev = port->serial->dev;
878 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
879 		if (result != 0) {
880 			priv->flags.read_urb_in_use = 0;
881 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
882 					" error %d\n", __func__, result);
883 		} else {
884 			resubmit = 0;
885 		}
886 	} else if (!transient) {
887 		unsigned long flags;
888 
889 		spin_lock_irqsave(&priv->lock, flags);
890 		if (priv->flags.write_urb_in_use == 0
891 				&& oti6858_buf_data_avail(priv->buf) != 0) {
892 			schedule_delayed_work(&priv->delayed_write_work, 0);
893 			resubmit = 0;
894 		}
895 		spin_unlock_irqrestore(&priv->lock, flags);
896 	}
897 
898 	if (resubmit) {
899 		int result;
900 
901 /*		dbg("%s(): submitting interrupt urb", __func__); */
902 		urb->dev = port->serial->dev;
903 		result = usb_submit_urb(urb, GFP_ATOMIC);
904 		if (result != 0) {
905 			dev_err(&urb->dev->dev,
906 					"%s(): usb_submit_urb() failed with"
907 					" error %d\n", __func__, result);
908 		}
909 	}
910 }
911 
912 static void oti6858_read_bulk_callback(struct urb *urb)
913 {
914 	struct usb_serial_port *port =  urb->context;
915 	struct oti6858_private *priv = usb_get_serial_port_data(port);
916 	struct tty_struct *tty;
917 	unsigned char *data = urb->transfer_buffer;
918 	unsigned long flags;
919 	int status = urb->status;
920 	int result;
921 
922 	dbg("%s(port = %d, status = %d)",
923 				__func__, port->number, status);
924 
925 	spin_lock_irqsave(&priv->lock, flags);
926 	priv->flags.read_urb_in_use = 0;
927 	spin_unlock_irqrestore(&priv->lock, flags);
928 
929 	if (status != 0) {
930 		if (!port->port.count) {
931 			dbg("%s(): port is closed, exiting", __func__);
932 			return;
933 		}
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 if we are still open */
958 	if (port->port.count != 0) {
959 		port->interrupt_in_urb->dev = port->serial->dev;
960 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
961 		if (result != 0) {
962 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
963 					" error %d\n", __func__, result);
964 		}
965 	}
966 }
967 
968 static void oti6858_write_bulk_callback(struct urb *urb)
969 {
970 	struct usb_serial_port *port =  urb->context;
971 	struct oti6858_private *priv = usb_get_serial_port_data(port);
972 	int status = urb->status;
973 	int result;
974 
975 	dbg("%s(port = %d, status = %d)",
976 				__func__, port->number, status);
977 
978 	switch (status) {
979 	case 0:
980 		/* success */
981 		break;
982 	case -ECONNRESET:
983 	case -ENOENT:
984 	case -ESHUTDOWN:
985 		/* this urb is terminated, clean up */
986 		dbg("%s(): urb shutting down with status: %d",
987 					__func__, status);
988 		priv->flags.write_urb_in_use = 0;
989 		return;
990 	default:
991 		/* error in the urb, so we have to resubmit it */
992 		dbg("%s(): nonzero write bulk status received: %d",
993 					__func__, status);
994 		dbg("%s(): overflow in write", __func__);
995 
996 		port->write_urb->transfer_buffer_length = 1;
997 		port->write_urb->dev = port->serial->dev;
998 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
999 		if (result) {
1000 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1001 					" error %d\n", __func__, result);
1002 		} else {
1003 			return;
1004 		}
1005 	}
1006 
1007 	priv->flags.write_urb_in_use = 0;
1008 
1009 	/* schedule the interrupt urb if we are still open */
1010 	port->interrupt_in_urb->dev = port->serial->dev;
1011 	dbg("%s(): submitting interrupt urb", __func__);
1012 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1013 	if (result != 0) {
1014 		dev_err(&port->dev, "%s(): failed submitting int urb,"
1015 					" error %d\n", __func__, result);
1016 	}
1017 }
1018 
1019 
1020 /*
1021  * oti6858_buf_alloc
1022  *
1023  * Allocate a circular buffer and all associated memory.
1024  */
1025 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
1026 {
1027 	struct oti6858_buf *pb;
1028 
1029 	if (size == 0)
1030 		return NULL;
1031 
1032 	pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
1033 	if (pb == NULL)
1034 		return NULL;
1035 
1036 	pb->buf_buf = kmalloc(size, GFP_KERNEL);
1037 	if (pb->buf_buf == NULL) {
1038 		kfree(pb);
1039 		return NULL;
1040 	}
1041 
1042 	pb->buf_size = size;
1043 	pb->buf_get = pb->buf_put = pb->buf_buf;
1044 
1045 	return pb;
1046 }
1047 
1048 /*
1049  * oti6858_buf_free
1050  *
1051  * Free the buffer and all associated memory.
1052  */
1053 static void oti6858_buf_free(struct oti6858_buf *pb)
1054 {
1055 	if (pb) {
1056 		kfree(pb->buf_buf);
1057 		kfree(pb);
1058 	}
1059 }
1060 
1061 /*
1062  * oti6858_buf_clear
1063  *
1064  * Clear out all data in the circular buffer.
1065  */
1066 static void oti6858_buf_clear(struct oti6858_buf *pb)
1067 {
1068 	if (pb != NULL) {
1069 		/* equivalent to a get of all data available */
1070 		pb->buf_get = pb->buf_put;
1071 	}
1072 }
1073 
1074 /*
1075  * oti6858_buf_data_avail
1076  *
1077  * Return the number of bytes of data available in the circular
1078  * buffer.
1079  */
1080 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
1081 {
1082 	if (pb == NULL)
1083 		return 0;
1084 	return (pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size;
1085 }
1086 
1087 /*
1088  * oti6858_buf_space_avail
1089  *
1090  * Return the number of bytes of space available in the circular
1091  * buffer.
1092  */
1093 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
1094 {
1095 	if (pb == NULL)
1096 		return 0;
1097 	return (pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size;
1098 }
1099 
1100 /*
1101  * oti6858_buf_put
1102  *
1103  * Copy data data from a user buffer and put it into the circular buffer.
1104  * Restrict to the amount of space available.
1105  *
1106  * Return the number of bytes copied.
1107  */
1108 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
1109 					unsigned int count)
1110 {
1111 	unsigned int len;
1112 
1113 	if (pb == NULL)
1114 		return 0;
1115 
1116 	len  = oti6858_buf_space_avail(pb);
1117 	if (count > len)
1118 		count = len;
1119 
1120 	if (count == 0)
1121 		return 0;
1122 
1123 	len = pb->buf_buf + pb->buf_size - pb->buf_put;
1124 	if (count > len) {
1125 		memcpy(pb->buf_put, buf, len);
1126 		memcpy(pb->buf_buf, buf+len, count - len);
1127 		pb->buf_put = pb->buf_buf + count - len;
1128 	} else {
1129 		memcpy(pb->buf_put, buf, count);
1130 		if (count < len)
1131 			pb->buf_put += count;
1132 		else /* count == len */
1133 			pb->buf_put = pb->buf_buf;
1134 	}
1135 
1136 	return count;
1137 }
1138 
1139 /*
1140  * oti6858_buf_get
1141  *
1142  * Get data from the circular buffer and copy to the given buffer.
1143  * Restrict to the amount of data available.
1144  *
1145  * Return the number of bytes copied.
1146  */
1147 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
1148 					unsigned int count)
1149 {
1150 	unsigned int len;
1151 
1152 	if (pb == NULL)
1153 		return 0;
1154 
1155 	len = oti6858_buf_data_avail(pb);
1156 	if (count > len)
1157 		count = len;
1158 
1159 	if (count == 0)
1160 		return 0;
1161 
1162 	len = pb->buf_buf + pb->buf_size - pb->buf_get;
1163 	if (count > len) {
1164 		memcpy(buf, pb->buf_get, len);
1165 		memcpy(buf+len, pb->buf_buf, count - len);
1166 		pb->buf_get = pb->buf_buf + count - len;
1167 	} else {
1168 		memcpy(buf, pb->buf_get, count);
1169 		if (count < len)
1170 			pb->buf_get += count;
1171 		else /* count == len */
1172 			pb->buf_get = pb->buf_buf;
1173 	}
1174 
1175 	return count;
1176 }
1177 
1178 /* module description and (de)initialization */
1179 
1180 static int __init oti6858_init(void)
1181 {
1182 	int retval;
1183 
1184 	retval = usb_serial_register(&oti6858_device);
1185 	if (retval == 0) {
1186 		retval = usb_register(&oti6858_driver);
1187 		if (retval)
1188 			usb_serial_deregister(&oti6858_device);
1189 	}
1190 	return retval;
1191 }
1192 
1193 static void __exit oti6858_exit(void)
1194 {
1195 	usb_deregister(&oti6858_driver);
1196 	usb_serial_deregister(&oti6858_device);
1197 }
1198 
1199 module_init(oti6858_init);
1200 module_exit(oti6858_exit);
1201 
1202 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1203 MODULE_AUTHOR(OTI6858_AUTHOR);
1204 MODULE_VERSION(OTI6858_VERSION);
1205 MODULE_LICENSE("GPL");
1206 
1207 module_param(debug, bool, S_IRUGO | S_IWUSR);
1208 MODULE_PARM_DESC(debug, "enable debug output");
1209 
1210