xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision 384740dc)
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 tty_struct *tty,
147 			struct usb_serial_port *port, struct file *filp);
148 static void oti6858_set_termios(struct tty_struct *tty,
149 			struct usb_serial_port *port, struct ktermios *old);
150 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
151 			unsigned int cmd, unsigned long arg);
152 static void oti6858_read_int_callback(struct urb *urb);
153 static void oti6858_read_bulk_callback(struct urb *urb);
154 static void oti6858_write_bulk_callback(struct urb *urb);
155 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
156 			const unsigned char *buf, int count);
157 static int oti6858_write_room(struct tty_struct *tty);
158 static int oti6858_chars_in_buffer(struct tty_struct *tty);
159 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file);
160 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
161 				unsigned int set, unsigned int clear);
162 static int oti6858_startup(struct usb_serial *serial);
163 static void oti6858_shutdown(struct usb_serial *serial);
164 
165 /* functions operating on buffers */
166 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size);
167 static void oti6858_buf_free(struct oti6858_buf *pb);
168 static void oti6858_buf_clear(struct oti6858_buf *pb);
169 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb);
170 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb);
171 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
172 					unsigned int count);
173 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
174 					unsigned int count);
175 
176 
177 /* device info */
178 static struct usb_serial_driver oti6858_device = {
179 	.driver = {
180 		.owner =	THIS_MODULE,
181 		.name =		"oti6858",
182 	},
183 	.id_table =		id_table,
184 	.num_ports =		1,
185 	.open =			oti6858_open,
186 	.close =		oti6858_close,
187 	.write =		oti6858_write,
188 	.ioctl =		oti6858_ioctl,
189 	.set_termios =		oti6858_set_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 	.shutdown =		oti6858_shutdown,
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 		u8 termios_initialized;
211 	} flags;
212 	struct delayed_work delayed_write_work;
213 
214 	struct {
215 		__le16 divisor;
216 		u8 frame_fmt;
217 		u8 control;
218 	} pending_setup;
219 	u8 transient;
220 	u8 setup_done;
221 	struct delayed_work delayed_setup_work;
222 
223 	wait_queue_head_t intr_wait;
224 	struct usb_serial_port *port;   /* USB port with which associated */
225 };
226 
227 #undef dbg
228 /* #define dbg(format, arg...) printk(KERN_INFO "%s: " format "\n", __FILE__, ## arg) */
229 #define dbg(format, arg...) printk(KERN_INFO "" format "\n", ## arg)
230 
231 static void setup_line(struct work_struct *work)
232 {
233 	struct oti6858_private *priv = container_of(work,
234 			struct oti6858_private, delayed_setup_work.work);
235 	struct usb_serial_port *port = priv->port;
236 	struct oti6858_control_pkt *new_setup;
237 	unsigned long flags;
238 	int result;
239 
240 	dbg("%s(port = %d)", __func__, port->number);
241 
242 	new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
243 	if (new_setup == NULL) {
244 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
245 		/* we will try again */
246 		schedule_delayed_work(&priv->delayed_setup_work,
247 						msecs_to_jiffies(2));
248 		return;
249 	}
250 
251 	result = usb_control_msg(port->serial->dev,
252 				usb_rcvctrlpipe(port->serial->dev, 0),
253 				OTI6858_REQ_T_GET_STATUS,
254 				OTI6858_REQ_GET_STATUS,
255 				0, 0,
256 				new_setup, OTI6858_CTRL_PKT_SIZE,
257 				100);
258 
259 	if (result != OTI6858_CTRL_PKT_SIZE) {
260 		dev_err(&port->dev, "%s(): error reading status\n", __func__);
261 		kfree(new_setup);
262 		/* we will try again */
263 		schedule_delayed_work(&priv->delayed_setup_work,
264 							msecs_to_jiffies(2));
265 		return;
266 	}
267 
268 	spin_lock_irqsave(&priv->lock, flags);
269 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
270 		new_setup->divisor = priv->pending_setup.divisor;
271 		new_setup->control = priv->pending_setup.control;
272 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
273 
274 		spin_unlock_irqrestore(&priv->lock, flags);
275 		result = usb_control_msg(port->serial->dev,
276 					usb_sndctrlpipe(port->serial->dev, 0),
277 					OTI6858_REQ_T_SET_LINE,
278 					OTI6858_REQ_SET_LINE,
279 					0, 0,
280 					new_setup, OTI6858_CTRL_PKT_SIZE,
281 					100);
282 	} else {
283 		spin_unlock_irqrestore(&priv->lock, flags);
284 		result = 0;
285 	}
286 	kfree(new_setup);
287 
288 	spin_lock_irqsave(&priv->lock, flags);
289 	if (result != OTI6858_CTRL_PKT_SIZE)
290 		priv->transient = 0;
291 	priv->setup_done = 1;
292 	spin_unlock_irqrestore(&priv->lock, flags);
293 
294 	dbg("%s(): submitting interrupt urb", __func__);
295 	port->interrupt_in_urb->dev = port->serial->dev;
296 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
297 	if (result != 0) {
298 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
299 				" with error %d\n", __func__, result);
300 	}
301 }
302 
303 void send_data(struct work_struct *work)
304 {
305 	struct oti6858_private *priv = container_of(work,
306 			struct oti6858_private, delayed_write_work.work);
307 	struct usb_serial_port *port = priv->port;
308 	int count = 0, result;
309 	unsigned long flags;
310 	unsigned char allow;
311 
312 	dbg("%s(port = %d)", __func__, port->number);
313 
314 	spin_lock_irqsave(&priv->lock, flags);
315 	if (priv->flags.write_urb_in_use) {
316 		spin_unlock_irqrestore(&priv->lock, flags);
317 		schedule_delayed_work(&priv->delayed_write_work,
318 						msecs_to_jiffies(2));
319 		return;
320 	}
321 	priv->flags.write_urb_in_use = 1;
322 
323 	count = oti6858_buf_data_avail(priv->buf);
324 	spin_unlock_irqrestore(&priv->lock, flags);
325 	if (count > port->bulk_out_size)
326 		count = port->bulk_out_size;
327 
328 	if (count != 0) {
329 		result = usb_control_msg(port->serial->dev,
330 				usb_rcvctrlpipe(port->serial->dev, 0),
331 				OTI6858_REQ_T_CHECK_TXBUFF,
332 				OTI6858_REQ_CHECK_TXBUFF,
333 				count, 0, &allow, 1, 100);
334 		if (result != 1 || allow != 0)
335 			count = 0;
336 	}
337 
338 	if (count == 0) {
339 		priv->flags.write_urb_in_use = 0;
340 
341 		dbg("%s(): submitting interrupt urb", __func__);
342 		port->interrupt_in_urb->dev = port->serial->dev;
343 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
344 		if (result != 0) {
345 			dev_err(&port->dev, "%s(): usb_submit_urb() failed"
346 				" with error %d\n", __func__, result);
347 		}
348 		return;
349 	}
350 
351 	spin_lock_irqsave(&priv->lock, flags);
352 	oti6858_buf_get(priv->buf, port->write_urb->transfer_buffer, count);
353 	spin_unlock_irqrestore(&priv->lock, flags);
354 
355 	port->write_urb->transfer_buffer_length = count;
356 	port->write_urb->dev = port->serial->dev;
357 	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
358 	if (result != 0) {
359 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
360 			       " with error %d\n", __func__, result);
361 		priv->flags.write_urb_in_use = 0;
362 	}
363 
364 	usb_serial_port_softint(port);
365 }
366 
367 static int oti6858_startup(struct usb_serial *serial)
368 {
369 	struct usb_serial_port *port = serial->port[0];
370 	struct oti6858_private *priv;
371 	int i;
372 
373 	for (i = 0; i < serial->num_ports; ++i) {
374 		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
375 		if (!priv)
376 			break;
377 		priv->buf = oti6858_buf_alloc(PL2303_BUF_SIZE);
378 		if (priv->buf == NULL) {
379 			kfree(priv);
380 			break;
381 		}
382 
383 		spin_lock_init(&priv->lock);
384 		init_waitqueue_head(&priv->intr_wait);
385 /*		INIT_WORK(&priv->setup_work, setup_line, serial->port[i]); */
386 /*		INIT_WORK(&priv->write_work, send_data, serial->port[i]); */
387 		priv->port = port;
388 		INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
389 		INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
390 
391 		usb_set_serial_port_data(serial->port[i], priv);
392 	}
393 	if (i == serial->num_ports)
394 		return 0;
395 
396 	for (--i; i >= 0; --i) {
397 		priv = usb_get_serial_port_data(serial->port[i]);
398 		oti6858_buf_free(priv->buf);
399 		kfree(priv);
400 		usb_set_serial_port_data(serial->port[i], NULL);
401 	}
402 	return -ENOMEM;
403 }
404 
405 static int oti6858_write(struct tty_struct *tty, struct usb_serial_port *port,
406 			const unsigned char *buf, int count)
407 {
408 	struct oti6858_private *priv = usb_get_serial_port_data(port);
409 	unsigned long flags;
410 
411 	dbg("%s(port = %d, count = %d)", __func__, port->number, count);
412 
413 	if (!count)
414 		return count;
415 
416 	spin_lock_irqsave(&priv->lock, flags);
417 	count = oti6858_buf_put(priv->buf, buf, count);
418 	spin_unlock_irqrestore(&priv->lock, flags);
419 
420 	return count;
421 }
422 
423 static int oti6858_write_room(struct tty_struct *tty)
424 {
425 	struct usb_serial_port *port = tty->driver_data;
426 	struct oti6858_private *priv = usb_get_serial_port_data(port);
427 	int room = 0;
428 	unsigned long flags;
429 
430 	dbg("%s(port = %d)", __func__, port->number);
431 
432 	spin_lock_irqsave(&priv->lock, flags);
433 	room = oti6858_buf_space_avail(priv->buf);
434 	spin_unlock_irqrestore(&priv->lock, flags);
435 
436 	return room;
437 }
438 
439 static int oti6858_chars_in_buffer(struct tty_struct *tty)
440 {
441 	struct usb_serial_port *port = tty->driver_data;
442 	struct oti6858_private *priv = usb_get_serial_port_data(port);
443 	int chars = 0;
444 	unsigned long flags;
445 
446 	dbg("%s(port = %d)", __func__, port->number);
447 
448 	spin_lock_irqsave(&priv->lock, flags);
449 	chars = oti6858_buf_data_avail(priv->buf);
450 	spin_unlock_irqrestore(&priv->lock, flags);
451 
452 	return chars;
453 }
454 
455 static void oti6858_set_termios(struct tty_struct *tty,
456 		struct usb_serial_port *port, struct ktermios *old_termios)
457 {
458 	struct oti6858_private *priv = usb_get_serial_port_data(port);
459 	unsigned long flags;
460 	unsigned int cflag;
461 	u8 frame_fmt, control;
462 	__le16 divisor;
463 	int br;
464 
465 	dbg("%s(port = %d)", __func__, port->number);
466 
467 	if (!tty) {
468 		dbg("%s(): no tty structures", __func__);
469 		return;
470 	}
471 
472 	spin_lock_irqsave(&priv->lock, flags);
473 	if (!priv->flags.termios_initialized) {
474 		*(tty->termios) = tty_std_termios;
475 		tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
476 		tty->termios->c_ispeed = 38400;
477 		tty->termios->c_ospeed = 38400;
478 		priv->flags.termios_initialized = 1;
479 	}
480 	spin_unlock_irqrestore(&priv->lock, flags);
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,
575 			struct usb_serial_port *port, struct file *filp)
576 {
577 	struct oti6858_private *priv = usb_get_serial_port_data(port);
578 	struct ktermios tmp_termios;
579 	struct usb_serial *serial = port->serial;
580 	struct oti6858_control_pkt *buf;
581 	unsigned long flags;
582 	int result;
583 
584 	dbg("%s(port = %d)", __func__, port->number);
585 
586 	usb_clear_halt(serial->dev, port->write_urb->pipe);
587 	usb_clear_halt(serial->dev, port->read_urb->pipe);
588 
589 	if (port->port.count != 1)
590 		return 0;
591 
592 	buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL);
593 	if (buf == NULL) {
594 		dev_err(&port->dev, "%s(): out of memory!\n", __func__);
595 		return -ENOMEM;
596 	}
597 
598 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
599 				OTI6858_REQ_T_GET_STATUS,
600 				OTI6858_REQ_GET_STATUS,
601 				0, 0,
602 				buf, OTI6858_CTRL_PKT_SIZE,
603 				100);
604 	if (result != OTI6858_CTRL_PKT_SIZE) {
605 		/* assume default (after power-on reset) values */
606 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
607 		buf->frame_fmt = 0x03;	/* 8N1 */
608 		buf->something = 0x43;
609 		buf->control = 0x4c;	/* DTR, RTS */
610 		buf->tx_status = 0x00;
611 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
612 		buf->rx_bytes_avail = 0x00;
613 	}
614 
615 	spin_lock_irqsave(&priv->lock, flags);
616 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
617 	priv->pending_setup.divisor = buf->divisor;
618 	priv->pending_setup.frame_fmt = buf->frame_fmt;
619 	priv->pending_setup.control = buf->control;
620 	spin_unlock_irqrestore(&priv->lock, flags);
621 	kfree(buf);
622 
623 	dbg("%s(): submitting interrupt urb", __func__);
624 	port->interrupt_in_urb->dev = serial->dev;
625 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
626 	if (result != 0) {
627 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
628 			       " with error %d\n", __func__, result);
629 		oti6858_close(tty, port, NULL);
630 		return -EPROTO;
631 	}
632 
633 	/* setup termios */
634 	if (tty)
635 		oti6858_set_termios(tty, port, &tmp_termios);
636 
637 	return 0;
638 }
639 
640 static void oti6858_close(struct tty_struct *tty,
641 			struct usb_serial_port *port, struct file *filp)
642 {
643 	struct oti6858_private *priv = usb_get_serial_port_data(port);
644 	unsigned long flags;
645 	long timeout;
646 	wait_queue_t wait;
647 
648 	dbg("%s(port = %d)", __func__, port->number);
649 
650 	/* wait for data to drain from the buffer */
651 	spin_lock_irqsave(&priv->lock, flags);
652 	timeout = 30 * HZ;	/* PL2303_CLOSING_WAIT */
653 	init_waitqueue_entry(&wait, current);
654 	add_wait_queue(&tty->write_wait, &wait);
655 	dbg("%s(): entering wait loop", __func__);
656 	for (;;) {
657 		set_current_state(TASK_INTERRUPTIBLE);
658 		if (oti6858_buf_data_avail(priv->buf) == 0
659 		|| timeout == 0 || signal_pending(current)
660 		|| port->serial->disconnected)
661 			break;
662 		spin_unlock_irqrestore(&priv->lock, flags);
663 		timeout = schedule_timeout(timeout);
664 		spin_lock_irqsave(&priv->lock, flags);
665 	}
666 	set_current_state(TASK_RUNNING);
667 	remove_wait_queue(&tty->write_wait, &wait);
668 	dbg("%s(): after wait loop", __func__);
669 
670 	/* clear out any remaining data in the buffer */
671 	oti6858_buf_clear(priv->buf);
672 	spin_unlock_irqrestore(&priv->lock, flags);
673 
674 	/* wait for characters to drain from the device */
675 	/* (this is long enough for the entire 256 byte */
676 	/* pl2303 hardware buffer to drain with no flow */
677 	/* control for data rates of 1200 bps or more, */
678 	/* for lower rates we should really know how much */
679 	/* data is in the buffer to compute a delay */
680 	/* that is not unnecessarily long) */
681 	/* FIXME
682 	bps = tty_get_baud_rate(tty);
683 	if (bps > 1200)
684 		timeout = max((HZ*2560)/bps,HZ/10);
685 	else
686 	*/
687 		timeout = 2*HZ;
688 	schedule_timeout_interruptible(timeout);
689 	dbg("%s(): after schedule_timeout_interruptible()", __func__);
690 
691 	/* cancel scheduled setup */
692 	cancel_delayed_work(&priv->delayed_setup_work);
693 	cancel_delayed_work(&priv->delayed_write_work);
694 	flush_scheduled_work();
695 
696 	/* shutdown our urbs */
697 	dbg("%s(): shutting down urbs", __func__);
698 	usb_kill_urb(port->write_urb);
699 	usb_kill_urb(port->read_urb);
700 	usb_kill_urb(port->interrupt_in_urb);
701 
702 	/*
703 	if (tty && (tty->termios->c_cflag) & HUPCL) {
704 		// drop DTR and RTS
705 		spin_lock_irqsave(&priv->lock, flags);
706 		priv->pending_setup.control &= ~CONTROL_MASK;
707 		spin_unlock_irqrestore(&priv->lock, flags);
708 	}
709 	*/
710 }
711 
712 static int oti6858_tiocmset(struct tty_struct *tty, struct file *file,
713 				unsigned int set, unsigned int clear)
714 {
715 	struct usb_serial_port *port = tty->driver_data;
716 	struct oti6858_private *priv = usb_get_serial_port_data(port);
717 	unsigned long flags;
718 	u8 control;
719 
720 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
721 				__func__, port->number, set, clear);
722 
723 	if (!usb_get_intfdata(port->serial->interface))
724 		return -ENODEV;
725 
726 	/* FIXME: check if this is correct (active high/low) */
727 	spin_lock_irqsave(&priv->lock, flags);
728 	control = priv->pending_setup.control;
729 	if ((set & TIOCM_RTS) != 0)
730 		control |= CONTROL_RTS_HIGH;
731 	if ((set & TIOCM_DTR) != 0)
732 		control |= CONTROL_DTR_HIGH;
733 	if ((clear & TIOCM_RTS) != 0)
734 		control &= ~CONTROL_RTS_HIGH;
735 	if ((clear & TIOCM_DTR) != 0)
736 		control &= ~CONTROL_DTR_HIGH;
737 
738 	if (control != priv->pending_setup.control)
739 		priv->pending_setup.control = control;
740 
741 	spin_unlock_irqrestore(&priv->lock, flags);
742 	return 0;
743 }
744 
745 static int oti6858_tiocmget(struct tty_struct *tty, struct file *file)
746 {
747 	struct usb_serial_port *port = tty->driver_data;
748 	struct oti6858_private *priv = usb_get_serial_port_data(port);
749 	unsigned long flags;
750 	unsigned pin_state;
751 	unsigned result = 0;
752 
753 	dbg("%s(port = %d)", __func__, port->number);
754 
755 	if (!usb_get_intfdata(port->serial->interface))
756 		return -ENODEV;
757 
758 	spin_lock_irqsave(&priv->lock, flags);
759 	pin_state = priv->status.pin_state & PIN_MASK;
760 	spin_unlock_irqrestore(&priv->lock, flags);
761 
762 	/* FIXME: check if this is correct (active high/low) */
763 	if ((pin_state & PIN_RTS) != 0)
764 		result |= TIOCM_RTS;
765 	if ((pin_state & PIN_CTS) != 0)
766 		result |= TIOCM_CTS;
767 	if ((pin_state & PIN_DSR) != 0)
768 		result |= TIOCM_DSR;
769 	if ((pin_state & PIN_DTR) != 0)
770 		result |= TIOCM_DTR;
771 	if ((pin_state & PIN_RI) != 0)
772 		result |= TIOCM_RI;
773 	if ((pin_state & PIN_DCD) != 0)
774 		result |= TIOCM_CD;
775 
776 	dbg("%s() = 0x%08x", __func__, result);
777 
778 	return result;
779 }
780 
781 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
782 {
783 	struct oti6858_private *priv = usb_get_serial_port_data(port);
784 	unsigned long flags;
785 	unsigned int prev, status;
786 	unsigned int changed;
787 
788 	spin_lock_irqsave(&priv->lock, flags);
789 	prev = priv->status.pin_state;
790 	spin_unlock_irqrestore(&priv->lock, flags);
791 
792 	while (1) {
793 		wait_event_interruptible(priv->intr_wait,
794 					priv->status.pin_state != prev);
795 		if (signal_pending(current))
796 			return -ERESTARTSYS;
797 
798 		spin_lock_irqsave(&priv->lock, flags);
799 		status = priv->status.pin_state & PIN_MASK;
800 		spin_unlock_irqrestore(&priv->lock, flags);
801 
802 		changed = prev ^ status;
803 		/* FIXME: check if this is correct (active high/low) */
804 		if (((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
805 		    ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
806 		    ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
807 		    ((arg & TIOCM_CTS) && (changed & PIN_CTS)))
808 			return 0;
809 		prev = status;
810 	}
811 
812 	/* NOTREACHED */
813 	return 0;
814 }
815 
816 static int oti6858_ioctl(struct tty_struct *tty, struct file *file,
817 			unsigned int cmd, unsigned long arg)
818 {
819 	struct usb_serial_port *port = tty->driver_data;
820 
821 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
822 				__func__, port->number, cmd, arg);
823 
824 	switch (cmd) {
825 	case TIOCMIWAIT:
826 		dbg("%s(): TIOCMIWAIT", __func__);
827 		return wait_modem_info(port, arg);
828 	default:
829 		dbg("%s(): 0x%04x not supported", __func__, cmd);
830 		break;
831 	}
832 	return -ENOIOCTLCMD;
833 }
834 
835 
836 static void oti6858_shutdown(struct usb_serial *serial)
837 {
838 	struct oti6858_private *priv;
839 	int i;
840 
841 	dbg("%s()", __func__);
842 
843 	for (i = 0; i < serial->num_ports; ++i) {
844 		priv = usb_get_serial_port_data(serial->port[i]);
845 		if (priv) {
846 			oti6858_buf_free(priv->buf);
847 			kfree(priv);
848 			usb_set_serial_port_data(serial->port[i], NULL);
849 		}
850 	}
851 }
852 
853 static void oti6858_read_int_callback(struct urb *urb)
854 {
855 	struct usb_serial_port *port =  urb->context;
856 	struct oti6858_private *priv = usb_get_serial_port_data(port);
857 	int transient = 0, can_recv = 0, resubmit = 1;
858 	int status = urb->status;
859 
860 	dbg("%s(port = %d, status = %d)",
861 				__func__, port->number, status);
862 
863 	switch (status) {
864 	case 0:
865 		/* success */
866 		break;
867 	case -ECONNRESET:
868 	case -ENOENT:
869 	case -ESHUTDOWN:
870 		/* this urb is terminated, clean up */
871 		dbg("%s(): urb shutting down with status: %d",
872 					__func__, status);
873 		return;
874 	default:
875 		dbg("%s(): nonzero urb status received: %d",
876 					__func__, status);
877 		break;
878 	}
879 
880 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
881 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
882 		unsigned long flags;
883 
884 		spin_lock_irqsave(&priv->lock, flags);
885 
886 		if (!priv->transient) {
887 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
888 				if (xs->rx_bytes_avail == 0) {
889 					priv->transient = 4;
890 					priv->setup_done = 0;
891 					resubmit = 0;
892 					dbg("%s(): scheduling setup_line()",
893 					    __func__);
894 					schedule_delayed_work(&priv->delayed_setup_work, 0);
895 				}
896 			}
897 		} else {
898 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
899 				priv->transient = 0;
900 			} else if (!priv->setup_done) {
901 				resubmit = 0;
902 			} else if (--priv->transient == 0) {
903 				if (xs->rx_bytes_avail == 0) {
904 					priv->transient = 4;
905 					priv->setup_done = 0;
906 					resubmit = 0;
907 					dbg("%s(): scheduling setup_line()",
908 					    __func__);
909 					schedule_delayed_work(&priv->delayed_setup_work, 0);
910 				}
911 			}
912 		}
913 
914 		if (!priv->transient) {
915 			if (xs->pin_state != priv->status.pin_state)
916 				wake_up_interruptible(&priv->intr_wait);
917 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
918 		}
919 
920 		if (!priv->transient && xs->rx_bytes_avail != 0) {
921 			can_recv = xs->rx_bytes_avail;
922 			priv->flags.read_urb_in_use = 1;
923 		}
924 
925 		transient = priv->transient;
926 		spin_unlock_irqrestore(&priv->lock, flags);
927 	}
928 
929 	if (can_recv) {
930 		int result;
931 
932 		port->read_urb->dev = port->serial->dev;
933 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
934 		if (result != 0) {
935 			priv->flags.read_urb_in_use = 0;
936 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
937 					" error %d\n", __func__, result);
938 		} else {
939 			resubmit = 0;
940 		}
941 	} else if (!transient) {
942 		unsigned long flags;
943 
944 		spin_lock_irqsave(&priv->lock, flags);
945 		if (priv->flags.write_urb_in_use == 0
946 				&& oti6858_buf_data_avail(priv->buf) != 0) {
947 			schedule_delayed_work(&priv->delayed_write_work, 0);
948 			resubmit = 0;
949 		}
950 		spin_unlock_irqrestore(&priv->lock, flags);
951 	}
952 
953 	if (resubmit) {
954 		int result;
955 
956 /*		dbg("%s(): submitting interrupt urb", __func__); */
957 		urb->dev = port->serial->dev;
958 		result = usb_submit_urb(urb, GFP_ATOMIC);
959 		if (result != 0) {
960 			dev_err(&urb->dev->dev,
961 					"%s(): usb_submit_urb() failed with"
962 					" error %d\n", __func__, result);
963 		}
964 	}
965 }
966 
967 static void oti6858_read_bulk_callback(struct urb *urb)
968 {
969 	struct usb_serial_port *port =  urb->context;
970 	struct oti6858_private *priv = usb_get_serial_port_data(port);
971 	struct tty_struct *tty;
972 	unsigned char *data = urb->transfer_buffer;
973 	unsigned long flags;
974 	int status = urb->status;
975 	int result;
976 
977 	dbg("%s(port = %d, status = %d)",
978 				__func__, port->number, status);
979 
980 	spin_lock_irqsave(&priv->lock, flags);
981 	priv->flags.read_urb_in_use = 0;
982 	spin_unlock_irqrestore(&priv->lock, flags);
983 
984 	if (status != 0) {
985 		if (!port->port.count) {
986 			dbg("%s(): port is closed, exiting", __func__);
987 			return;
988 		}
989 		/*
990 		if (status == -EPROTO) {
991 			* PL2303 mysteriously fails with -EPROTO reschedule
992 			   the read *
993 			dbg("%s - caught -EPROTO, resubmitting the urb",
994 								__func__);
995 			result = usb_submit_urb(urb, GFP_ATOMIC);
996 			if (result)
997 				dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __func__, result);
998 			return;
999 		}
1000 		*/
1001 		dbg("%s(): unable to handle the error, exiting", __func__);
1002 		return;
1003 	}
1004 
1005 	tty = port->port.tty;
1006 	if (tty != NULL && urb->actual_length > 0) {
1007 		tty_insert_flip_string(tty, data, urb->actual_length);
1008 		tty_flip_buffer_push(tty);
1009 	}
1010 
1011 	/* schedule the interrupt urb if we are still open */
1012 	if (port->port.count != 0) {
1013 		port->interrupt_in_urb->dev = port->serial->dev;
1014 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1015 		if (result != 0) {
1016 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1017 					" error %d\n", __func__, result);
1018 		}
1019 	}
1020 }
1021 
1022 static void oti6858_write_bulk_callback(struct urb *urb)
1023 {
1024 	struct usb_serial_port *port =  urb->context;
1025 	struct oti6858_private *priv = usb_get_serial_port_data(port);
1026 	int status = urb->status;
1027 	int result;
1028 
1029 	dbg("%s(port = %d, status = %d)",
1030 				__func__, port->number, status);
1031 
1032 	switch (status) {
1033 	case 0:
1034 		/* success */
1035 		break;
1036 	case -ECONNRESET:
1037 	case -ENOENT:
1038 	case -ESHUTDOWN:
1039 		/* this urb is terminated, clean up */
1040 		dbg("%s(): urb shutting down with status: %d",
1041 					__func__, status);
1042 		priv->flags.write_urb_in_use = 0;
1043 		return;
1044 	default:
1045 		/* error in the urb, so we have to resubmit it */
1046 		dbg("%s(): nonzero write bulk status received: %d",
1047 					__func__, status);
1048 		dbg("%s(): overflow in write", __func__);
1049 
1050 		port->write_urb->transfer_buffer_length = 1;
1051 		port->write_urb->dev = port->serial->dev;
1052 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
1053 		if (result) {
1054 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1055 					" error %d\n", __func__, result);
1056 		} else {
1057 			return;
1058 		}
1059 	}
1060 
1061 	priv->flags.write_urb_in_use = 0;
1062 
1063 	/* schedule the interrupt urb if we are still open */
1064 	port->interrupt_in_urb->dev = port->serial->dev;
1065 	dbg("%s(): submitting interrupt urb", __func__);
1066 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1067 	if (result != 0) {
1068 		dev_err(&port->dev, "%s(): failed submitting int urb,"
1069 					" error %d\n", __func__, result);
1070 	}
1071 }
1072 
1073 
1074 /*
1075  * oti6858_buf_alloc
1076  *
1077  * Allocate a circular buffer and all associated memory.
1078  */
1079 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
1080 {
1081 	struct oti6858_buf *pb;
1082 
1083 	if (size == 0)
1084 		return NULL;
1085 
1086 	pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
1087 	if (pb == NULL)
1088 		return NULL;
1089 
1090 	pb->buf_buf = kmalloc(size, GFP_KERNEL);
1091 	if (pb->buf_buf == NULL) {
1092 		kfree(pb);
1093 		return NULL;
1094 	}
1095 
1096 	pb->buf_size = size;
1097 	pb->buf_get = pb->buf_put = pb->buf_buf;
1098 
1099 	return pb;
1100 }
1101 
1102 /*
1103  * oti6858_buf_free
1104  *
1105  * Free the buffer and all associated memory.
1106  */
1107 static void oti6858_buf_free(struct oti6858_buf *pb)
1108 {
1109 	if (pb) {
1110 		kfree(pb->buf_buf);
1111 		kfree(pb);
1112 	}
1113 }
1114 
1115 /*
1116  * oti6858_buf_clear
1117  *
1118  * Clear out all data in the circular buffer.
1119  */
1120 static void oti6858_buf_clear(struct oti6858_buf *pb)
1121 {
1122 	if (pb != NULL) {
1123 		/* equivalent to a get of all data available */
1124 		pb->buf_get = pb->buf_put;
1125 	}
1126 }
1127 
1128 /*
1129  * oti6858_buf_data_avail
1130  *
1131  * Return the number of bytes of data available in the circular
1132  * buffer.
1133  */
1134 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
1135 {
1136 	if (pb == NULL)
1137 		return 0;
1138 	return (pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size;
1139 }
1140 
1141 /*
1142  * oti6858_buf_space_avail
1143  *
1144  * Return the number of bytes of space available in the circular
1145  * buffer.
1146  */
1147 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
1148 {
1149 	if (pb == NULL)
1150 		return 0;
1151 	return (pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size;
1152 }
1153 
1154 /*
1155  * oti6858_buf_put
1156  *
1157  * Copy data data from a user buffer and put it into the circular buffer.
1158  * Restrict to the amount of space available.
1159  *
1160  * Return the number of bytes copied.
1161  */
1162 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
1163 					unsigned int count)
1164 {
1165 	unsigned int len;
1166 
1167 	if (pb == NULL)
1168 		return 0;
1169 
1170 	len  = oti6858_buf_space_avail(pb);
1171 	if (count > len)
1172 		count = len;
1173 
1174 	if (count == 0)
1175 		return 0;
1176 
1177 	len = pb->buf_buf + pb->buf_size - pb->buf_put;
1178 	if (count > len) {
1179 		memcpy(pb->buf_put, buf, len);
1180 		memcpy(pb->buf_buf, buf+len, count - len);
1181 		pb->buf_put = pb->buf_buf + count - len;
1182 	} else {
1183 		memcpy(pb->buf_put, buf, count);
1184 		if (count < len)
1185 			pb->buf_put += count;
1186 		else /* count == len */
1187 			pb->buf_put = pb->buf_buf;
1188 	}
1189 
1190 	return count;
1191 }
1192 
1193 /*
1194  * oti6858_buf_get
1195  *
1196  * Get data from the circular buffer and copy to the given buffer.
1197  * Restrict to the amount of data available.
1198  *
1199  * Return the number of bytes copied.
1200  */
1201 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
1202 					unsigned int count)
1203 {
1204 	unsigned int len;
1205 
1206 	if (pb == NULL)
1207 		return 0;
1208 
1209 	len = oti6858_buf_data_avail(pb);
1210 	if (count > len)
1211 		count = len;
1212 
1213 	if (count == 0)
1214 		return 0;
1215 
1216 	len = pb->buf_buf + pb->buf_size - pb->buf_get;
1217 	if (count > len) {
1218 		memcpy(buf, pb->buf_get, len);
1219 		memcpy(buf+len, pb->buf_buf, count - len);
1220 		pb->buf_get = pb->buf_buf + count - len;
1221 	} else {
1222 		memcpy(buf, pb->buf_get, count);
1223 		if (count < len)
1224 			pb->buf_get += count;
1225 		else /* count == len */
1226 			pb->buf_get = pb->buf_buf;
1227 	}
1228 
1229 	return count;
1230 }
1231 
1232 /* module description and (de)initialization */
1233 
1234 static int __init oti6858_init(void)
1235 {
1236 	int retval;
1237 
1238 	retval = usb_serial_register(&oti6858_device);
1239 	if (retval == 0) {
1240 		retval = usb_register(&oti6858_driver);
1241 		if (retval)
1242 			usb_serial_deregister(&oti6858_device);
1243 	}
1244 	return retval;
1245 }
1246 
1247 static void __exit oti6858_exit(void)
1248 {
1249 	usb_deregister(&oti6858_driver);
1250 	usb_serial_deregister(&oti6858_device);
1251 }
1252 
1253 module_init(oti6858_init);
1254 module_exit(oti6858_exit);
1255 
1256 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1257 MODULE_AUTHOR(OTI6858_AUTHOR);
1258 MODULE_VERSION(OTI6858_VERSION);
1259 MODULE_LICENSE("GPL");
1260 
1261 module_param(debug, bool, S_IRUGO | S_IWUSR);
1262 MODULE_PARM_DESC(debug, "enable debug output");
1263 
1264