xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision 5f5bac82)
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,
145 			struct usb_serial_port *port, struct file *filp);
146 static void oti6858_close(struct usb_serial_port *port);
147 static void oti6858_set_termios(struct tty_struct *tty,
148 			struct usb_serial_port *port, struct ktermios *old);
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_shutdown(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 	.tiocmget =		oti6858_tiocmget,
190 	.tiocmset =		oti6858_tiocmset,
191 	.read_bulk_callback =	oti6858_read_bulk_callback,
192 	.read_int_callback =	oti6858_read_int_callback,
193 	.write_bulk_callback =	oti6858_write_bulk_callback,
194 	.write_room =		oti6858_write_room,
195 	.chars_in_buffer =	oti6858_chars_in_buffer,
196 	.attach =		oti6858_startup,
197 	.shutdown =		oti6858_shutdown,
198 };
199 
200 struct oti6858_private {
201 	spinlock_t lock;
202 
203 	struct oti6858_buf *buf;
204 	struct oti6858_control_pkt status;
205 
206 	struct {
207 		u8 read_urb_in_use;
208 		u8 write_urb_in_use;
209 		u8 termios_initialized;
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_set_termios(struct tty_struct *tty,
451 		struct usb_serial_port *port, struct ktermios *old_termios)
452 {
453 	struct oti6858_private *priv = usb_get_serial_port_data(port);
454 	unsigned long flags;
455 	unsigned int cflag;
456 	u8 frame_fmt, control;
457 	__le16 divisor;
458 	int br;
459 
460 	dbg("%s(port = %d)", __func__, port->number);
461 
462 	if (!tty) {
463 		dbg("%s(): no tty structures", __func__);
464 		return;
465 	}
466 
467 	spin_lock_irqsave(&priv->lock, flags);
468 	if (!priv->flags.termios_initialized) {
469 		*(tty->termios) = tty_std_termios;
470 		tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
471 		tty->termios->c_ispeed = 38400;
472 		tty->termios->c_ospeed = 38400;
473 		priv->flags.termios_initialized = 1;
474 	}
475 	spin_unlock_irqrestore(&priv->lock, flags);
476 
477 	cflag = tty->termios->c_cflag;
478 
479 	spin_lock_irqsave(&priv->lock, flags);
480 	divisor = priv->pending_setup.divisor;
481 	frame_fmt = priv->pending_setup.frame_fmt;
482 	control = priv->pending_setup.control;
483 	spin_unlock_irqrestore(&priv->lock, flags);
484 
485 	frame_fmt &= ~FMT_DATA_BITS_MASK;
486 	switch (cflag & CSIZE) {
487 	case CS5:
488 		frame_fmt |= FMT_DATA_BITS_5;
489 		break;
490 	case CS6:
491 		frame_fmt |= FMT_DATA_BITS_6;
492 		break;
493 	case CS7:
494 		frame_fmt |= FMT_DATA_BITS_7;
495 		break;
496 	default:
497 	case CS8:
498 		frame_fmt |= FMT_DATA_BITS_8;
499 		break;
500 	}
501 
502 	/* manufacturer claims that this device can work with baud rates
503 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
504 	 * guarantee that any other baud rate will work (especially
505 	 * the higher ones)
506 	 */
507 	br = tty_get_baud_rate(tty);
508 	if (br == 0) {
509 		divisor = 0;
510 	} else {
511 		int real_br;
512 		int new_divisor;
513 		br = min(br, OTI6858_MAX_BAUD_RATE);
514 
515 		new_divisor = (96000000 + 8 * br) / (16 * br);
516 		real_br = 96000000 / (16 * new_divisor);
517 		divisor = cpu_to_le16(new_divisor);
518 		tty_encode_baud_rate(tty, real_br, real_br);
519 	}
520 
521 	frame_fmt &= ~FMT_STOP_BITS_MASK;
522 	if ((cflag & CSTOPB) != 0)
523 		frame_fmt |= FMT_STOP_BITS_2;
524 	else
525 		frame_fmt |= FMT_STOP_BITS_1;
526 
527 	frame_fmt &= ~FMT_PARITY_MASK;
528 	if ((cflag & PARENB) != 0) {
529 		if ((cflag & PARODD) != 0)
530 			frame_fmt |= FMT_PARITY_ODD;
531 		else
532 			frame_fmt |= FMT_PARITY_EVEN;
533 	} else {
534 		frame_fmt |= FMT_PARITY_NONE;
535 	}
536 
537 	control &= ~CONTROL_MASK;
538 	if ((cflag & CRTSCTS) != 0)
539 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
540 
541 	/* change control lines if we are switching to or from B0 */
542 	/* FIXME:
543 	spin_lock_irqsave(&priv->lock, flags);
544 	control = priv->line_control;
545 	if ((cflag & CBAUD) == B0)
546 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
547 	else
548 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
549 	if (control != priv->line_control) {
550 		control = priv->line_control;
551 		spin_unlock_irqrestore(&priv->lock, flags);
552 		set_control_lines(serial->dev, control);
553 	} else {
554 		spin_unlock_irqrestore(&priv->lock, flags);
555 	}
556 	*/
557 
558 	spin_lock_irqsave(&priv->lock, flags);
559 	if (divisor != priv->pending_setup.divisor
560 			|| control != priv->pending_setup.control
561 			|| frame_fmt != priv->pending_setup.frame_fmt) {
562 		priv->pending_setup.divisor = divisor;
563 		priv->pending_setup.control = control;
564 		priv->pending_setup.frame_fmt = frame_fmt;
565 	}
566 	spin_unlock_irqrestore(&priv->lock, flags);
567 }
568 
569 static int oti6858_open(struct tty_struct *tty,
570 			struct usb_serial_port *port, struct file *filp)
571 {
572 	struct oti6858_private *priv = usb_get_serial_port_data(port);
573 	struct ktermios tmp_termios;
574 	struct usb_serial *serial = port->serial;
575 	struct oti6858_control_pkt *buf;
576 	unsigned long flags;
577 	int result;
578 
579 	dbg("%s(port = %d)", __func__, port->number);
580 
581 	usb_clear_halt(serial->dev, port->write_urb->pipe);
582 	usb_clear_halt(serial->dev, port->read_urb->pipe);
583 
584 	if (port->port.count != 1)
585 		return 0;
586 
587 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
588 	if (buf == NULL) {
589 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
590 		return -ENOMEM;
591 	}
592 
593 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
594 				OTI6858_REQ_T_GET_STATUS,
595 				OTI6858_REQ_GET_STATUS,
596 				0, 0,
597 				buf, OTI6858_CTRL_PKT_SIZE,
598 				100);
599 	if (result != OTI6858_CTRL_PKT_SIZE) {
600 		/* assume default (after power-on reset) values */
601 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
602 		buf->frame_fmt = 0x03;	/* 8N1 */
603 		buf->something = 0x43;
604 		buf->control = 0x4c;	/* DTR, RTS */
605 		buf->tx_status = 0x00;
606 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
607 		buf->rx_bytes_avail = 0x00;
608 	}
609 
610 	spin_lock_irqsave(&priv->lock, flags);
611 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
612 	priv->pending_setup.divisor = buf->divisor;
613 	priv->pending_setup.frame_fmt = buf->frame_fmt;
614 	priv->pending_setup.control = buf->control;
615 	spin_unlock_irqrestore(&priv->lock, flags);
616 	kfree(buf);
617 
618 	dbg("%s(): submitting interrupt urb", __func__);
619 	port->interrupt_in_urb->dev = serial->dev;
620 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
621 	if (result != 0) {
622 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
623 			       " with error %d\n", __func__, result);
624 		oti6858_close(port);
625 		return -EPROTO;
626 	}
627 
628 	/* setup termios */
629 	if (tty)
630 		oti6858_set_termios(tty, port, &tmp_termios);
631 	port->port.drain_delay = 256;	/* FIXME: check the FIFO length */
632 	return 0;
633 }
634 
635 static void oti6858_close(struct usb_serial_port *port)
636 {
637 	struct oti6858_private *priv = usb_get_serial_port_data(port);
638 	unsigned long flags;
639 
640 	dbg("%s(port = %d)", __func__, port->number);
641 
642 	spin_lock_irqsave(&priv->lock, flags);
643 	/* clear out any remaining data in the buffer */
644 	oti6858_buf_clear(priv->buf);
645 	spin_unlock_irqrestore(&priv->lock, flags);
646 
647 	dbg("%s(): after buf_clear()", __func__);
648 
649 	/* cancel scheduled setup */
650 	cancel_delayed_work(&priv->delayed_setup_work);
651 	cancel_delayed_work(&priv->delayed_write_work);
652 	flush_scheduled_work();
653 
654 	/* shutdown our urbs */
655 	dbg("%s(): shutting down urbs", __func__);
656 	usb_kill_urb(port->write_urb);
657 	usb_kill_urb(port->read_urb);
658 	usb_kill_urb(port->interrupt_in_urb);
659 }
660 
661 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
662 				unsigned int set, unsigned int clear)
663 {
664 	struct usb_serial_port *port = tty->driver_data;
665 	struct oti6858_private *priv = usb_get_serial_port_data(port);
666 	unsigned long flags;
667 	u8 control;
668 
669 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
670 				__func__, port->number, set, clear);
671 
672 	if (!usb_get_intfdata(port->serial->interface))
673 		return -ENODEV;
674 
675 	/* FIXME: check if this is correct (active high/low) */
676 	spin_lock_irqsave(&priv->lock, flags);
677 	control = priv->pending_setup.control;
678 	if ((set & TIOCM_RTS) != 0)
679 		control |= CONTROL_RTS_HIGH;
680 	if ((set & TIOCM_DTR) != 0)
681 		control |= CONTROL_DTR_HIGH;
682 	if ((clear & TIOCM_RTS) != 0)
683 		control &= ~CONTROL_RTS_HIGH;
684 	if ((clear & TIOCM_DTR) != 0)
685 		control &= ~CONTROL_DTR_HIGH;
686 
687 	if (control != priv->pending_setup.control)
688 		priv->pending_setup.control = control;
689 
690 	spin_unlock_irqrestore(&priv->lock, flags);
691 	return 0;
692 }
693 
694 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file)
695 {
696 	struct usb_serial_port *port = tty->driver_data;
697 	struct oti6858_private *priv = usb_get_serial_port_data(port);
698 	unsigned long flags;
699 	unsigned pin_state;
700 	unsigned result = 0;
701 
702 	dbg("%s(port = %d)", __func__, port->number);
703 
704 	if (!usb_get_intfdata(port->serial->interface))
705 		return -ENODEV;
706 
707 	spin_lock_irqsave(&priv->lock, flags);
708 	pin_state = priv->status.pin_state & PIN_MASK;
709 	spin_unlock_irqrestore(&priv->lock, flags);
710 
711 	/* FIXME: check if this is correct (active high/low) */
712 	if ((pin_state & PIN_RTS) != 0)
713 		result |= TIOCM_RTS;
714 	if ((pin_state & PIN_CTS) != 0)
715 		result |= TIOCM_CTS;
716 	if ((pin_state & PIN_DSR) != 0)
717 		result |= TIOCM_DSR;
718 	if ((pin_state & PIN_DTR) != 0)
719 		result |= TIOCM_DTR;
720 	if ((pin_state & PIN_RI) != 0)
721 		result |= TIOCM_RI;
722 	if ((pin_state & PIN_DCD) != 0)
723 		result |= TIOCM_CD;
724 
725 	dbg("%s() = 0x%08x", __func__, result);
726 
727 	return result;
728 }
729 
730 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
731 {
732 	struct oti6858_private *priv = usb_get_serial_port_data(port);
733 	unsigned long flags;
734 	unsigned int prev, status;
735 	unsigned int changed;
736 
737 	spin_lock_irqsave(&priv->lock, flags);
738 	prev = priv->status.pin_state;
739 	spin_unlock_irqrestore(&priv->lock, flags);
740 
741 	while (1) {
742 		wait_event_interruptible(priv->intr_wait,
743 					priv->status.pin_state != prev);
744 		if (signal_pending(current))
745 			return -ERESTARTSYS;
746 
747 		spin_lock_irqsave(&priv->lock, flags);
748 		status = priv->status.pin_state & PIN_MASK;
749 		spin_unlock_irqrestore(&priv->lock, flags);
750 
751 		changed = prev ^ status;
752 		/* FIXME: check if this is correct (active high/low) */
753 		if (((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
754 		    ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
755 		    ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
756 		    ((arg & TIOCM_CTS) && (changed & PIN_CTS)))
757 			return 0;
758 		prev = status;
759 	}
760 
761 	/* NOTREACHED */
762 	return 0;
763 }
764 
765 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
766 			unsigned int cmd, unsigned long arg)
767 {
768 	struct usb_serial_port *port = tty->driver_data;
769 
770 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
771 				__func__, port->number, cmd, arg);
772 
773 	switch (cmd) {
774 	case TIOCMIWAIT:
775 		dbg("%s(): TIOCMIWAIT", __func__);
776 		return wait_modem_info(port, arg);
777 	default:
778 		dbg("%s(): 0x%04x not supported", __func__, cmd);
779 		break;
780 	}
781 	return -ENOIOCTLCMD;
782 }
783 
784 
785 static void oti6858_shutdown(struct usb_serial *serial)
786 {
787 	struct oti6858_private *priv;
788 	int i;
789 
790 	dbg("%s()", __func__);
791 
792 	for (i = 0; i < serial->num_ports; ++i) {
793 		priv = usb_get_serial_port_data(serial->port[i]);
794 		if (priv) {
795 			oti6858_buf_free(priv->buf);
796 			kfree(priv);
797 			usb_set_serial_port_data(serial->port[i], NULL);
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 		if (!port->port.count) {
935 			dbg("%s(): port is closed, exiting", __func__);
936 			return;
937 		}
938 		/*
939 		if (status == -EPROTO) {
940 			* PL2303 mysteriously fails with -EPROTO reschedule
941 			   the read *
942 			dbg("%s - caught -EPROTO, resubmitting the urb",
943 								__func__);
944 			result = usb_submit_urb(urb, GFP_ATOMIC);
945 			if (result)
946 				dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __func__, result);
947 			return;
948 		}
949 		*/
950 		dbg("%s(): unable to handle the error, exiting", __func__);
951 		return;
952 	}
953 
954 	tty = tty_port_tty_get(&port->port);
955 	if (tty != NULL && urb->actual_length > 0) {
956 		tty_insert_flip_string(tty, data, urb->actual_length);
957 		tty_flip_buffer_push(tty);
958 	}
959 	tty_kref_put(tty);
960 
961 	/* schedule the interrupt urb if we are still open */
962 	if (port->port.count != 0) {
963 		port->interrupt_in_urb->dev = port->serial->dev;
964 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
965 		if (result != 0) {
966 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
967 					" error %d\n", __func__, result);
968 		}
969 	}
970 }
971 
972 static void oti6858_write_bulk_callback(struct urb *urb)
973 {
974 	struct usb_serial_port *port =  urb->context;
975 	struct oti6858_private *priv = usb_get_serial_port_data(port);
976 	int status = urb->status;
977 	int result;
978 
979 	dbg("%s(port = %d, status = %d)",
980 				__func__, port->number, status);
981 
982 	switch (status) {
983 	case 0:
984 		/* success */
985 		break;
986 	case -ECONNRESET:
987 	case -ENOENT:
988 	case -ESHUTDOWN:
989 		/* this urb is terminated, clean up */
990 		dbg("%s(): urb shutting down with status: %d",
991 					__func__, status);
992 		priv->flags.write_urb_in_use = 0;
993 		return;
994 	default:
995 		/* error in the urb, so we have to resubmit it */
996 		dbg("%s(): nonzero write bulk status received: %d",
997 					__func__, status);
998 		dbg("%s(): overflow in write", __func__);
999 
1000 		port->write_urb->transfer_buffer_length = 1;
1001 		port->write_urb->dev = port->serial->dev;
1002 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
1003 		if (result) {
1004 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1005 					" error %d\n", __func__, result);
1006 		} else {
1007 			return;
1008 		}
1009 	}
1010 
1011 	priv->flags.write_urb_in_use = 0;
1012 
1013 	/* schedule the interrupt urb if we are still open */
1014 	port->interrupt_in_urb->dev = port->serial->dev;
1015 	dbg("%s(): submitting interrupt urb", __func__);
1016 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1017 	if (result != 0) {
1018 		dev_err(&port->dev, "%s(): failed submitting int urb,"
1019 					" error %d\n", __func__, result);
1020 	}
1021 }
1022 
1023 
1024 /*
1025  * oti6858_buf_alloc
1026  *
1027  * Allocate a circular buffer and all associated memory.
1028  */
1029 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
1030 {
1031 	struct oti6858_buf *pb;
1032 
1033 	if (size == 0)
1034 		return NULL;
1035 
1036 	pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
1037 	if (pb == NULL)
1038 		return NULL;
1039 
1040 	pb->buf_buf = kmalloc(size, GFP_KERNEL);
1041 	if (pb->buf_buf == NULL) {
1042 		kfree(pb);
1043 		return NULL;
1044 	}
1045 
1046 	pb->buf_size = size;
1047 	pb->buf_get = pb->buf_put = pb->buf_buf;
1048 
1049 	return pb;
1050 }
1051 
1052 /*
1053  * oti6858_buf_free
1054  *
1055  * Free the buffer and all associated memory.
1056  */
1057 static void oti6858_buf_free(struct oti6858_buf *pb)
1058 {
1059 	if (pb) {
1060 		kfree(pb->buf_buf);
1061 		kfree(pb);
1062 	}
1063 }
1064 
1065 /*
1066  * oti6858_buf_clear
1067  *
1068  * Clear out all data in the circular buffer.
1069  */
1070 static void oti6858_buf_clear(struct oti6858_buf *pb)
1071 {
1072 	if (pb != NULL) {
1073 		/* equivalent to a get of all data available */
1074 		pb->buf_get = pb->buf_put;
1075 	}
1076 }
1077 
1078 /*
1079  * oti6858_buf_data_avail
1080  *
1081  * Return the number of bytes of data available in the circular
1082  * buffer.
1083  */
1084 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
1085 {
1086 	if (pb == NULL)
1087 		return 0;
1088 	return (pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size;
1089 }
1090 
1091 /*
1092  * oti6858_buf_space_avail
1093  *
1094  * Return the number of bytes of space available in the circular
1095  * buffer.
1096  */
1097 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
1098 {
1099 	if (pb == NULL)
1100 		return 0;
1101 	return (pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size;
1102 }
1103 
1104 /*
1105  * oti6858_buf_put
1106  *
1107  * Copy data data from a user buffer and put it into the circular buffer.
1108  * Restrict to the amount of space available.
1109  *
1110  * Return the number of bytes copied.
1111  */
1112 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
1113 					unsigned int count)
1114 {
1115 	unsigned int len;
1116 
1117 	if (pb == NULL)
1118 		return 0;
1119 
1120 	len  = oti6858_buf_space_avail(pb);
1121 	if (count > len)
1122 		count = len;
1123 
1124 	if (count == 0)
1125 		return 0;
1126 
1127 	len = pb->buf_buf + pb->buf_size - pb->buf_put;
1128 	if (count > len) {
1129 		memcpy(pb->buf_put, buf, len);
1130 		memcpy(pb->buf_buf, buf+len, count - len);
1131 		pb->buf_put = pb->buf_buf + count - len;
1132 	} else {
1133 		memcpy(pb->buf_put, buf, count);
1134 		if (count < len)
1135 			pb->buf_put += count;
1136 		else /* count == len */
1137 			pb->buf_put = pb->buf_buf;
1138 	}
1139 
1140 	return count;
1141 }
1142 
1143 /*
1144  * oti6858_buf_get
1145  *
1146  * Get data from the circular buffer and copy to the given buffer.
1147  * Restrict to the amount of data available.
1148  *
1149  * Return the number of bytes copied.
1150  */
1151 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
1152 					unsigned int count)
1153 {
1154 	unsigned int len;
1155 
1156 	if (pb == NULL)
1157 		return 0;
1158 
1159 	len = oti6858_buf_data_avail(pb);
1160 	if (count > len)
1161 		count = len;
1162 
1163 	if (count == 0)
1164 		return 0;
1165 
1166 	len = pb->buf_buf + pb->buf_size - pb->buf_get;
1167 	if (count > len) {
1168 		memcpy(buf, pb->buf_get, len);
1169 		memcpy(buf+len, pb->buf_buf, count - len);
1170 		pb->buf_get = pb->buf_buf + count - len;
1171 	} else {
1172 		memcpy(buf, pb->buf_get, count);
1173 		if (count < len)
1174 			pb->buf_get += count;
1175 		else /* count == len */
1176 			pb->buf_get = pb->buf_buf;
1177 	}
1178 
1179 	return count;
1180 }
1181 
1182 /* module description and (de)initialization */
1183 
1184 static int __init oti6858_init(void)
1185 {
1186 	int retval;
1187 
1188 	retval = usb_serial_register(&oti6858_device);
1189 	if (retval == 0) {
1190 		retval = usb_register(&oti6858_driver);
1191 		if (retval)
1192 			usb_serial_deregister(&oti6858_device);
1193 	}
1194 	return retval;
1195 }
1196 
1197 static void __exit oti6858_exit(void)
1198 {
1199 	usb_deregister(&oti6858_driver);
1200 	usb_serial_deregister(&oti6858_device);
1201 }
1202 
1203 module_init(oti6858_init);
1204 module_exit(oti6858_exit);
1205 
1206 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1207 MODULE_AUTHOR(OTI6858_AUTHOR);
1208 MODULE_VERSION(OTI6858_VERSION);
1209 MODULE_LICENSE("GPL");
1210 
1211 module_param(debug, bool, S_IRUGO | S_IWUSR);
1212 MODULE_PARM_DESC(debug, "enable debug output");
1213 
1214