xref: /openbmc/linux/drivers/usb/serial/oti6858.c (revision c21b37f6)
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 driver
29  *
30  * TODO:
31  *  - implement correct flushing for ioctls and oti6858_close()
32  *  - check how errors (rx overflow, parity error, framing error) are reported
33  *  - implement oti6858_break_ctl()
34  *  - implement more ioctls
35  *  - test/implement flow control
36  *  - allow setting custom baud rates
37  */
38 
39 #include <linux/kernel.h>
40 #include <linux/errno.h>
41 #include <linux/init.h>
42 #include <linux/slab.h>
43 #include <linux/tty.h>
44 #include <linux/tty_driver.h>
45 #include <linux/tty_flip.h>
46 #include <linux/serial.h>
47 #include <linux/module.h>
48 #include <linux/moduleparam.h>
49 #include <linux/spinlock.h>
50 #include <linux/usb.h>
51 #include <linux/usb/serial.h>
52 #include <asm/uaccess.h>
53 #include "oti6858.h"
54 
55 #define OTI6858_DESCRIPTION \
56 	"Ours Technology Inc. OTi-6858 USB to serial adapter driver"
57 #define OTI6858_AUTHOR "Tomasz Michal Lukaszewski <FIXME@FIXME>"
58 #define OTI6858_VERSION "0.1"
59 
60 static struct usb_device_id id_table [] = {
61 	{ USB_DEVICE(OTI6858_VENDOR_ID, OTI6858_PRODUCT_ID) },
62 	{ }
63 };
64 
65 MODULE_DEVICE_TABLE(usb, id_table);
66 
67 static struct usb_driver oti6858_driver = {
68 	.name =		"oti6858",
69 	.probe =	usb_serial_probe,
70 	.disconnect =	usb_serial_disconnect,
71 	.id_table =	id_table,
72 	.no_dynamic_id = 	1,
73 };
74 
75 static int debug;
76 
77 
78 /* buffering code, copied from pl2303 driver */
79 #define PL2303_BUF_SIZE		1024
80 #define PL2303_TMP_BUF_SIZE	1024
81 
82 struct pl2303_buf {
83 	unsigned int	buf_size;
84 	char		*buf_buf;
85 	char		*buf_get;
86 	char		*buf_put;
87 };
88 
89 /* requests */
90 #define	OTI6858_REQ_GET_STATUS		(USB_DIR_IN | USB_TYPE_VENDOR | 0x00)
91 #define	OTI6858_REQ_T_GET_STATUS	0x01
92 
93 #define	OTI6858_REQ_SET_LINE		(USB_DIR_OUT | USB_TYPE_VENDOR | 0x00)
94 #define	OTI6858_REQ_T_SET_LINE		0x00
95 
96 #define	OTI6858_REQ_CHECK_TXBUFF	(USB_DIR_IN | USB_TYPE_VENDOR | 0x01)
97 #define	OTI6858_REQ_T_CHECK_TXBUFF	0x00
98 
99 /* format of the control packet */
100 struct oti6858_control_pkt {
101 	u16	divisor;	/* baud rate = 96000000 / (16 * divisor), LE */
102 #define OTI6858_MAX_BAUD_RATE	3000000
103 	u8	frame_fmt;
104 #define FMT_STOP_BITS_MASK	0xc0
105 #define FMT_STOP_BITS_1		0x00
106 #define FMT_STOP_BITS_2		0x40	/* 1.5 stop bits if FMT_DATA_BITS_5 */
107 #define FMT_PARITY_MASK		0x38
108 #define FMT_PARITY_NONE		0x00
109 #define FMT_PARITY_ODD		0x08
110 #define FMT_PARITY_EVEN		0x18
111 #define FMT_PARITY_MARK		0x28
112 #define FMT_PARITY_SPACE	0x38
113 #define FMT_DATA_BITS_MASK	0x03
114 #define FMT_DATA_BITS_5		0x00
115 #define FMT_DATA_BITS_6		0x01
116 #define FMT_DATA_BITS_7		0x02
117 #define FMT_DATA_BITS_8		0x03
118 	u8	something;	/* always equals 0x43 */
119 	u8	control;	/* settings of flow control lines */
120 #define CONTROL_MASK		0x0c
121 #define CONTROL_DTR_HIGH	0x08
122 #define CONTROL_RTS_HIGH	0x04
123 	u8	tx_status;
124 #define	TX_BUFFER_EMPTIED	0x09
125 	u8	pin_state;
126 #define PIN_MASK		0x3f
127 #define PIN_RTS			0x20	/* output pin */
128 #define PIN_CTS			0x10	/* input pin, active low */
129 #define PIN_DSR			0x08	/* input pin, active low */
130 #define PIN_DTR			0x04	/* output pin */
131 #define PIN_RI			0x02	/* input pin, active low */
132 #define PIN_DCD			0x01	/* input pin, active low */
133 	u8	rx_bytes_avail;		/* number of bytes in rx buffer */;
134 };
135 
136 #define OTI6858_CTRL_PKT_SIZE	sizeof(struct oti6858_control_pkt)
137 #define OTI6858_CTRL_EQUALS_PENDING(a, priv) \
138 	(    ((a)->divisor == (priv)->pending_setup.divisor) \
139 	  && ((a)->control == (priv)->pending_setup.control) \
140 	  && ((a)->frame_fmt == (priv)->pending_setup.frame_fmt) )
141 
142 /* function prototypes */
143 static int oti6858_open(struct usb_serial_port *port, struct file *filp);
144 static void oti6858_close(struct usb_serial_port *port, struct file *filp);
145 static void oti6858_set_termios(struct usb_serial_port *port,
146 				struct ktermios *old);
147 static int oti6858_ioctl(struct usb_serial_port *port, struct file *file,
148 			unsigned int cmd, unsigned long arg);
149 static void oti6858_read_int_callback(struct urb *urb);
150 static void oti6858_read_bulk_callback(struct urb *urb);
151 static void oti6858_write_bulk_callback(struct urb *urb);
152 static int oti6858_write(struct usb_serial_port *port,
153 			const unsigned char *buf, int count);
154 static int oti6858_write_room(struct usb_serial_port *port);
155 static void oti6858_break_ctl(struct usb_serial_port *port, int break_state);
156 static int oti6858_chars_in_buffer(struct usb_serial_port *port);
157 static int oti6858_tiocmget(struct usb_serial_port *port, struct file *file);
158 static int oti6858_tiocmset(struct usb_serial_port *port, struct file *file,
159 				unsigned int set, unsigned int clear);
160 static int oti6858_startup(struct usb_serial *serial);
161 static void oti6858_shutdown(struct usb_serial *serial);
162 
163 /* functions operating on buffers */
164 static struct pl2303_buf *pl2303_buf_alloc(unsigned int size);
165 static void pl2303_buf_free(struct pl2303_buf *pb);
166 static void pl2303_buf_clear(struct pl2303_buf *pb);
167 static unsigned int pl2303_buf_data_avail(struct pl2303_buf *pb);
168 static unsigned int pl2303_buf_space_avail(struct pl2303_buf *pb);
169 static unsigned int pl2303_buf_put(struct pl2303_buf *pb, const char *buf,
170 					unsigned int count);
171 static unsigned int pl2303_buf_get(struct pl2303_buf *pb, char *buf,
172 					unsigned int count);
173 
174 
175 /* device info */
176 static struct usb_serial_driver oti6858_device = {
177 	.driver = {
178 		.owner =	THIS_MODULE,
179 		.name =		"oti6858",
180 	},
181 	.id_table =		id_table,
182 	.num_interrupt_in =	1,
183 	.num_bulk_in =		1,
184 	.num_bulk_out =		1,
185 	.num_ports =		1,
186 	.open =			oti6858_open,
187 	.close =		oti6858_close,
188 	.write =		oti6858_write,
189 	.ioctl =		oti6858_ioctl,
190 	.break_ctl =		oti6858_break_ctl,
191 	.set_termios =		oti6858_set_termios,
192 	.tiocmget =		oti6858_tiocmget,
193 	.tiocmset =		oti6858_tiocmset,
194 	.read_bulk_callback =	oti6858_read_bulk_callback,
195 	.read_int_callback =	oti6858_read_int_callback,
196 	.write_bulk_callback =	oti6858_write_bulk_callback,
197 	.write_room =		oti6858_write_room,
198 	.chars_in_buffer =	oti6858_chars_in_buffer,
199 	.attach =		oti6858_startup,
200 	.shutdown =		oti6858_shutdown,
201 };
202 
203 struct oti6858_private {
204 	spinlock_t lock;
205 
206 	struct pl2303_buf *buf;
207 	struct oti6858_control_pkt status;
208 
209 	struct {
210 		u8 read_urb_in_use;
211 		u8 write_urb_in_use;
212 		u8 termios_initialized;
213 	} flags;
214 	struct delayed_work delayed_write_work;
215 
216 	struct {
217 		u16 divisor;
218 		u8 frame_fmt;
219 		u8 control;
220 	} pending_setup;
221 	u8 transient;
222 	u8 setup_done;
223 	struct delayed_work delayed_setup_work;
224 
225 	wait_queue_head_t intr_wait;
226         struct usb_serial_port *port;   /* USB port with which associated */
227 };
228 
229 #undef dbg
230 /* #define dbg(format, arg...) printk(KERN_INFO "%s: " format "\n", __FILE__, ## arg) */
231 #define dbg(format, arg...) printk(KERN_INFO "" format "\n", ## arg)
232 
233 static void setup_line(struct work_struct *work)
234 {
235 	struct oti6858_private *priv = container_of(work, struct oti6858_private, delayed_setup_work.work);
236 	struct usb_serial_port *port = priv->port;
237 	struct oti6858_control_pkt *new_setup;
238 	unsigned long flags;
239 	int result;
240 
241 	dbg("%s(port = %d)", __FUNCTION__, port->number);
242 
243 	if ((new_setup = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL)) == NULL) {
244 		dev_err(&port->dev, "%s(): out of memory!\n", __FUNCTION__);
245 		/* we will try again */
246 		schedule_delayed_work(&priv->delayed_setup_work, msecs_to_jiffies(2));
247 		return;
248 	}
249 
250 	result = usb_control_msg(port->serial->dev,
251 				usb_rcvctrlpipe(port->serial->dev, 0),
252 				OTI6858_REQ_T_GET_STATUS,
253 				OTI6858_REQ_GET_STATUS,
254 				0, 0,
255 				new_setup, OTI6858_CTRL_PKT_SIZE,
256 				100);
257 
258 	if (result != OTI6858_CTRL_PKT_SIZE) {
259 		dev_err(&port->dev, "%s(): error reading status", __FUNCTION__);
260 		kfree(new_setup);
261 		/* we will try again */
262 		schedule_delayed_work(&priv->delayed_setup_work, msecs_to_jiffies(2));
263 		return;
264 	}
265 
266 	spin_lock_irqsave(&priv->lock, flags);
267 	if (!OTI6858_CTRL_EQUALS_PENDING(new_setup, priv)) {
268 		new_setup->divisor = priv->pending_setup.divisor;
269 		new_setup->control = priv->pending_setup.control;
270 		new_setup->frame_fmt = priv->pending_setup.frame_fmt;
271 
272 		spin_unlock_irqrestore(&priv->lock, flags);
273 		result = usb_control_msg(port->serial->dev,
274 					usb_sndctrlpipe(port->serial->dev, 0),
275 					OTI6858_REQ_T_SET_LINE,
276 					OTI6858_REQ_SET_LINE,
277 					0, 0,
278 					new_setup, OTI6858_CTRL_PKT_SIZE,
279 					100);
280 	} else {
281 		spin_unlock_irqrestore(&priv->lock, flags);
282 		result = 0;
283 	}
284 	kfree(new_setup);
285 
286 	spin_lock_irqsave(&priv->lock, flags);
287 	if (result != OTI6858_CTRL_PKT_SIZE)
288 		priv->transient = 0;
289 	priv->setup_done = 1;
290 	spin_unlock_irqrestore(&priv->lock, flags);
291 
292 	dbg("%s(): submitting interrupt urb", __FUNCTION__);
293 	port->interrupt_in_urb->dev = port->serial->dev;
294 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
295 	if (result != 0) {
296 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
297 				" with error %d\n", __FUNCTION__, result);
298 	}
299 }
300 
301 void send_data(struct work_struct *work)
302 {
303 	struct oti6858_private *priv = container_of(work, struct oti6858_private, delayed_write_work.work);
304 	struct usb_serial_port *port = priv->port;
305 	int count = 0, result;
306 	unsigned long flags;
307 	unsigned char allow;
308 
309 	dbg("%s(port = %d)", __FUNCTION__, port->number);
310 
311 	spin_lock_irqsave(&priv->lock, flags);
312 	if (priv->flags.write_urb_in_use) {
313 		spin_unlock_irqrestore(&priv->lock, flags);
314 		schedule_delayed_work(&priv->delayed_write_work, msecs_to_jiffies(2));
315 		return;
316 	}
317 	priv->flags.write_urb_in_use = 1;
318 
319 	count = pl2303_buf_data_avail(priv->buf);
320 	spin_unlock_irqrestore(&priv->lock, flags);
321 	if (count > port->bulk_out_size)
322 		count = port->bulk_out_size;
323 
324 	if (count != 0) {
325 		result = usb_control_msg(port->serial->dev,
326 				usb_rcvctrlpipe(port->serial->dev, 0),
327 				OTI6858_REQ_T_CHECK_TXBUFF,
328 				OTI6858_REQ_CHECK_TXBUFF,
329 				count, 0, &allow, 1, 100);
330 		if (result != 1 || allow != 0)
331 			count = 0;
332 	}
333 
334 	if (count == 0) {
335 		priv->flags.write_urb_in_use = 0;
336 
337 		dbg("%s(): submitting interrupt urb", __FUNCTION__);
338 		port->interrupt_in_urb->dev = port->serial->dev;
339 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
340 		if (result != 0) {
341 			dev_err(&port->dev, "%s(): usb_submit_urb() failed"
342 				" with error %d\n", __FUNCTION__, result);
343 		}
344 		return;
345 	}
346 
347 	spin_lock_irqsave(&priv->lock, flags);
348 	pl2303_buf_get(priv->buf, port->write_urb->transfer_buffer, count);
349 	spin_unlock_irqrestore(&priv->lock, flags);
350 
351 	port->write_urb->transfer_buffer_length = count;
352 	port->write_urb->dev = port->serial->dev;
353 	result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
354 	if (result != 0) {
355 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
356 			       " with error %d\n", __FUNCTION__, result);
357 		priv->flags.write_urb_in_use = 0;
358 	}
359 
360 	usb_serial_port_softint(port);
361 }
362 
363 static int oti6858_startup(struct usb_serial *serial)
364 {
365         struct usb_serial_port *port = serial->port[0];
366         struct oti6858_private *priv;
367 	int i;
368 
369 	for (i = 0; i < serial->num_ports; ++i) {
370 		priv = kzalloc(sizeof(struct oti6858_private), GFP_KERNEL);
371 		if (!priv)
372 			break;
373 		priv->buf = pl2303_buf_alloc(PL2303_BUF_SIZE);
374 		if (priv->buf == NULL) {
375 			kfree(priv);
376 			break;
377 		}
378 
379 		spin_lock_init(&priv->lock);
380 		init_waitqueue_head(&priv->intr_wait);
381 //		INIT_WORK(&priv->setup_work, setup_line, serial->port[i]);
382 //		INIT_WORK(&priv->write_work, send_data, serial->port[i]);
383 		priv->port = port;
384 		INIT_DELAYED_WORK(&priv->delayed_setup_work, setup_line);
385 		INIT_DELAYED_WORK(&priv->delayed_write_work, send_data);
386 
387 		usb_set_serial_port_data(serial->port[i], priv);
388 	}
389 	if (i == serial->num_ports)
390 		return 0;
391 
392 	for (--i; i >= 0; --i) {
393 		priv = usb_get_serial_port_data(serial->port[i]);
394 		pl2303_buf_free(priv->buf);
395 		kfree(priv);
396 		usb_set_serial_port_data(serial->port[i], NULL);
397 	}
398 	return -ENOMEM;
399 }
400 
401 static int oti6858_write(struct usb_serial_port *port,
402 			const unsigned char *buf, int count)
403 {
404 	struct oti6858_private *priv = usb_get_serial_port_data(port);
405 	unsigned long flags;
406 
407 	dbg("%s(port = %d, count = %d)", __FUNCTION__, port->number, count);
408 
409 	if (!count)
410 		return count;
411 
412 	spin_lock_irqsave(&priv->lock, flags);
413 	count = pl2303_buf_put(priv->buf, buf, count);
414 	spin_unlock_irqrestore(&priv->lock, flags);
415 
416 	return count;
417 }
418 
419 static int oti6858_write_room(struct usb_serial_port *port)
420 {
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)", __FUNCTION__, port->number);
426 
427 	spin_lock_irqsave(&priv->lock, flags);
428 	room = pl2303_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 usb_serial_port *port)
435 {
436 	struct oti6858_private *priv = usb_get_serial_port_data(port);
437 	int chars = 0;
438 	unsigned long flags;
439 
440 	dbg("%s(port = %d)", __FUNCTION__, port->number);
441 
442 	spin_lock_irqsave(&priv->lock, flags);
443 	chars = pl2303_buf_data_avail(priv->buf);
444 	spin_unlock_irqrestore(&priv->lock, flags);
445 
446 	return chars;
447 }
448 
449 static void oti6858_set_termios(struct usb_serial_port *port,
450 				struct ktermios *old_termios)
451 {
452 	struct oti6858_private *priv = usb_get_serial_port_data(port);
453 	unsigned long flags;
454 	unsigned int cflag;
455 	u8 frame_fmt, control;
456 	u16 divisor;
457 	int br;
458 
459 	dbg("%s(port = %d)", __FUNCTION__, port->number);
460 
461 	if ((!port->tty) || (!port->tty->termios)) {
462 		dbg("%s(): no tty structures", __FUNCTION__);
463 		return;
464 	}
465 
466 	spin_lock_irqsave(&priv->lock, flags);
467 	if (!priv->flags.termios_initialized) {
468 		*(port->tty->termios) = tty_std_termios;
469 		port->tty->termios->c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
470 		priv->flags.termios_initialized = 1;
471 	}
472 	spin_unlock_irqrestore(&priv->lock, flags);
473 
474 	cflag = port->tty->termios->c_cflag;
475 
476 	spin_lock_irqsave(&priv->lock, flags);
477 	divisor = priv->pending_setup.divisor;
478 	frame_fmt = priv->pending_setup.frame_fmt;
479 	control = priv->pending_setup.control;
480 	spin_unlock_irqrestore(&priv->lock, flags);
481 
482 	frame_fmt &= ~FMT_DATA_BITS_MASK;
483 	switch (cflag & CSIZE) {
484 		case CS5:
485 			frame_fmt |= FMT_DATA_BITS_5;
486 			break;
487 		case CS6:
488 			frame_fmt |= FMT_DATA_BITS_6;
489 			break;
490 		case CS7:
491 			frame_fmt |= FMT_DATA_BITS_7;
492 			break;
493 		default:
494 		case CS8:
495 			frame_fmt |= FMT_DATA_BITS_8;
496 			break;
497 	}
498 
499 	/* manufacturer claims that this device can work with baud rates
500 	 * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
501 	 * guarantee that any other baud rate will work (especially
502 	 * the higher ones)
503 	 */
504 	br = tty_get_baud_rate(port->tty);
505 	if (br == 0) {
506 		divisor = 0;
507 	} else if (br <= OTI6858_MAX_BAUD_RATE) {
508 		int real_br;
509 
510 		divisor = (96000000 + 8 * br) / (16 * br);
511 		real_br = 96000000 / (16 * divisor);
512 		if ((((real_br - br) * 100 + br - 1) / br) > 2) {
513 			dbg("%s(): baud rate %d is invalid", __FUNCTION__, br);
514 			return;
515 		}
516 		divisor = cpu_to_le16(divisor);
517 	} else {
518 		dbg("%s(): baud rate %d is too high", __FUNCTION__, br);
519 		return;
520 	}
521 
522 	frame_fmt &= ~FMT_STOP_BITS_MASK;
523 	if ((cflag & CSTOPB) != 0) {
524 		frame_fmt |= FMT_STOP_BITS_2;
525 	} else {
526 		frame_fmt |= FMT_STOP_BITS_1;
527 	}
528 
529 	frame_fmt &= ~FMT_PARITY_MASK;
530 	if ((cflag & PARENB) != 0) {
531 		if ((cflag & PARODD) != 0) {
532 			frame_fmt |= FMT_PARITY_ODD;
533 		} else {
534 			frame_fmt |= FMT_PARITY_EVEN;
535 		}
536 	} else {
537 		frame_fmt |= FMT_PARITY_NONE;
538 	}
539 
540 	control &= ~CONTROL_MASK;
541 	if ((cflag & CRTSCTS) != 0)
542 		control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
543 
544 	/* change control lines if we are switching to or from B0 */
545 	/* FIXME:
546 	spin_lock_irqsave(&priv->lock, flags);
547 	control = priv->line_control;
548 	if ((cflag & CBAUD) == B0)
549 		priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
550 	else
551 		priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
552 	if (control != priv->line_control) {
553 		control = priv->line_control;
554 		spin_unlock_irqrestore(&priv->lock, flags);
555 		set_control_lines(serial->dev, control);
556 	} else {
557 		spin_unlock_irqrestore(&priv->lock, flags);
558 	}
559 	*/
560 
561 	spin_lock_irqsave(&priv->lock, flags);
562 	if (divisor != priv->pending_setup.divisor
563 			|| control != priv->pending_setup.control
564 			|| frame_fmt != priv->pending_setup.frame_fmt) {
565 		priv->pending_setup.divisor = divisor;
566 		priv->pending_setup.control = control;
567 		priv->pending_setup.frame_fmt = frame_fmt;
568 	}
569 	spin_unlock_irqrestore(&priv->lock, flags);
570 }
571 
572 static int oti6858_open(struct usb_serial_port *port, struct file *filp)
573 {
574 	struct oti6858_private *priv = usb_get_serial_port_data(port);
575 	struct ktermios tmp_termios;
576 	struct usb_serial *serial = port->serial;
577 	struct oti6858_control_pkt *buf;
578 	unsigned long flags;
579 	int result;
580 
581 	dbg("%s(port = %d)", __FUNCTION__, port->number);
582 
583 	usb_clear_halt(serial->dev, port->write_urb->pipe);
584 	usb_clear_halt(serial->dev, port->read_urb->pipe);
585 
586 	if (port->open_count != 1)
587 		return 0;
588 
589 	if ((buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL)) == NULL) {
590 		dev_err(&port->dev, "%s(): out of memory!\n", __FUNCTION__);
591 		return -ENOMEM;
592 	}
593 
594 	result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
595 				OTI6858_REQ_T_GET_STATUS,
596 				OTI6858_REQ_GET_STATUS,
597 				0, 0,
598 				buf, OTI6858_CTRL_PKT_SIZE,
599 				100);
600 	if (result != OTI6858_CTRL_PKT_SIZE) {
601 		/* assume default (after power-on reset) values */
602 		buf->divisor = cpu_to_le16(0x009c);	/* 38400 bps */
603 		buf->frame_fmt = 0x03;	/* 8N1 */
604 		buf->something = 0x43;
605 		buf->control = 0x4c;	/* DTR, RTS */
606 		buf->tx_status = 0x00;
607 		buf->pin_state = 0x5b;	/* RTS, CTS, DSR, DTR, RI, DCD */
608 		buf->rx_bytes_avail = 0x00;
609 	}
610 
611 	spin_lock_irqsave(&priv->lock, flags);
612 	memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
613 	priv->pending_setup.divisor = buf->divisor;
614 	priv->pending_setup.frame_fmt = buf->frame_fmt;
615 	priv->pending_setup.control = buf->control;
616 	spin_unlock_irqrestore(&priv->lock, flags);
617 	kfree(buf);
618 
619 	dbg("%s(): submitting interrupt urb", __FUNCTION__);
620 	port->interrupt_in_urb->dev = serial->dev;
621 	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
622 	if (result != 0) {
623 		dev_err(&port->dev, "%s(): usb_submit_urb() failed"
624 			       " with error %d\n", __FUNCTION__, result);
625 		oti6858_close(port, NULL);
626 		return -EPROTO;
627 	}
628 
629 	/* setup termios */
630 	if (port->tty)
631 		oti6858_set_termios(port, &tmp_termios);
632 
633 	return 0;
634 }
635 
636 static void oti6858_close(struct usb_serial_port *port, struct file *filp)
637 {
638 	struct oti6858_private *priv = usb_get_serial_port_data(port);
639 	unsigned long flags;
640 	long timeout;
641 	wait_queue_t wait;
642 
643 	dbg("%s(port = %d)", __FUNCTION__, port->number);
644 
645 	/* wait for data to drain from the buffer */
646 	spin_lock_irqsave(&priv->lock, flags);
647 	timeout = 30 * HZ;	/* PL2303_CLOSING_WAIT */
648 	init_waitqueue_entry(&wait, current);
649 	add_wait_queue(&port->tty->write_wait, &wait);
650 	dbg("%s(): entering wait loop", __FUNCTION__);
651 	for (;;) {
652 		set_current_state(TASK_INTERRUPTIBLE);
653 		if (pl2303_buf_data_avail(priv->buf) == 0
654 		|| timeout == 0 || signal_pending(current)
655 		|| !usb_get_intfdata(port->serial->interface))	/* disconnect */
656 			break;
657 		spin_unlock_irqrestore(&priv->lock, flags);
658 		timeout = schedule_timeout(timeout);
659 		spin_lock_irqsave(&priv->lock, flags);
660 	}
661 	set_current_state(TASK_RUNNING);
662 	remove_wait_queue(&port->tty->write_wait, &wait);
663 	dbg("%s(): after wait loop", __FUNCTION__);
664 
665 	/* clear out any remaining data in the buffer */
666 	pl2303_buf_clear(priv->buf);
667 	spin_unlock_irqrestore(&priv->lock, flags);
668 
669 	/* wait for characters to drain from the device */
670 	/* (this is long enough for the entire 256 byte */
671 	/* pl2303 hardware buffer to drain with no flow */
672 	/* control for data rates of 1200 bps or more, */
673 	/* for lower rates we should really know how much */
674 	/* data is in the buffer to compute a delay */
675 	/* that is not unnecessarily long) */
676 	/* FIXME
677 	bps = tty_get_baud_rate(port->tty);
678 	if (bps > 1200)
679 		timeout = max((HZ*2560)/bps,HZ/10);
680 	else
681 	*/
682 		timeout = 2*HZ;
683 	schedule_timeout_interruptible(timeout);
684 	dbg("%s(): after schedule_timeout_interruptible()", __FUNCTION__);
685 
686 	/* cancel scheduled setup */
687 	cancel_delayed_work(&priv->delayed_setup_work);
688 	cancel_delayed_work(&priv->delayed_write_work);
689 	flush_scheduled_work();
690 
691 	/* shutdown our urbs */
692 	dbg("%s(): shutting down urbs", __FUNCTION__);
693 	usb_kill_urb(port->write_urb);
694 	usb_kill_urb(port->read_urb);
695 	usb_kill_urb(port->interrupt_in_urb);
696 
697 	/*
698 	if (port->tty && (port->tty->termios->c_cflag) & HUPCL) {
699 		// drop DTR and RTS
700 		spin_lock_irqsave(&priv->lock, flags);
701 		priv->pending_setup.control &= ~CONTROL_MASK;
702 		spin_unlock_irqrestore(&priv->lock, flags);
703 	}
704 	*/
705 }
706 
707 static int oti6858_tiocmset(struct usb_serial_port *port, struct file *file,
708 				unsigned int set, unsigned int clear)
709 {
710 	struct oti6858_private *priv = usb_get_serial_port_data(port);
711 	unsigned long flags;
712 	u8 control;
713 
714 	dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
715 				__FUNCTION__, port->number, set, clear);
716 
717 	if (!usb_get_intfdata(port->serial->interface))
718 		return -ENODEV;
719 
720 	/* FIXME: check if this is correct (active high/low) */
721 	spin_lock_irqsave(&priv->lock, flags);
722 	control = priv->pending_setup.control;
723 	if ((set & TIOCM_RTS) != 0)
724 		control |= CONTROL_RTS_HIGH;
725 	if ((set & TIOCM_DTR) != 0)
726 		control |= CONTROL_DTR_HIGH;
727 	if ((clear & TIOCM_RTS) != 0)
728 		control &= ~CONTROL_RTS_HIGH;
729 	if ((clear & TIOCM_DTR) != 0)
730 		control &= ~CONTROL_DTR_HIGH;
731 
732 	if (control != priv->pending_setup.control) {
733 		priv->pending_setup.control = control;
734 	}
735 	spin_unlock_irqrestore(&priv->lock, flags);
736 
737 	return 0;
738 }
739 
740 static int oti6858_tiocmget(struct usb_serial_port *port, struct file *file)
741 {
742 	struct oti6858_private *priv = usb_get_serial_port_data(port);
743 	unsigned long flags;
744 	unsigned pin_state;
745 	unsigned result = 0;
746 
747 	dbg("%s(port = %d)", __FUNCTION__, port->number);
748 
749 	if (!usb_get_intfdata(port->serial->interface))
750 		return -ENODEV;
751 
752 	spin_lock_irqsave(&priv->lock, flags);
753 	pin_state = priv->status.pin_state & PIN_MASK;
754 	spin_unlock_irqrestore(&priv->lock, flags);
755 
756 	/* FIXME: check if this is correct (active high/low) */
757 	if ((pin_state & PIN_RTS) != 0)
758 		result |= TIOCM_RTS;
759 	if ((pin_state & PIN_CTS) != 0)
760 		result |= TIOCM_CTS;
761 	if ((pin_state & PIN_DSR) != 0)
762 		result |= TIOCM_DSR;
763 	if ((pin_state & PIN_DTR) != 0)
764 		result |= TIOCM_DTR;
765 	if ((pin_state & PIN_RI) != 0)
766 		result |= TIOCM_RI;
767 	if ((pin_state & PIN_DCD) != 0)
768 		result |= TIOCM_CD;
769 
770 	dbg("%s() = 0x%08x", __FUNCTION__, result);
771 
772 	return result;
773 }
774 
775 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
776 {
777 	struct oti6858_private *priv = usb_get_serial_port_data(port);
778 	unsigned long flags;
779 	unsigned int prev, status;
780 	unsigned int changed;
781 
782 	spin_lock_irqsave(&priv->lock, flags);
783 	prev = priv->status.pin_state;
784 	spin_unlock_irqrestore(&priv->lock, flags);
785 
786 	while (1) {
787 		wait_event_interruptible(priv->intr_wait, priv->status.pin_state != prev);
788 		if (signal_pending(current))
789 			return -ERESTARTSYS;
790 
791 		spin_lock_irqsave(&priv->lock, flags);
792 		status = priv->status.pin_state & PIN_MASK;
793 		spin_unlock_irqrestore(&priv->lock, flags);
794 
795 		changed = prev ^ status;
796 		/* FIXME: check if this is correct (active high/low) */
797 		if (	((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
798 			((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
799 			((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
800 			((arg & TIOCM_CTS) && (changed & PIN_CTS))) {
801 				return 0;
802 		}
803 		prev = status;
804 	}
805 
806 	/* NOTREACHED */
807 	return 0;
808 }
809 
810 static int oti6858_ioctl(struct usb_serial_port *port, struct file *file,
811 			unsigned int cmd, unsigned long arg)
812 {
813 	void __user *user_arg = (void __user *) arg;
814 	unsigned int x;
815 
816 	dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
817 				__FUNCTION__, port->number, cmd, arg);
818 
819 	switch (cmd) {
820 		case TCGETS:
821 			if (copy_to_user(user_arg, port->tty->termios,
822 						sizeof(struct ktermios))) {
823 				return -EFAULT;
824 			}
825 			return 0;
826 
827 		case TCSETS:
828 		case TCSETSW:	/* FIXME: this is not the same! */
829 		case TCSETSF:	/* FIXME: this is not the same! */
830 			if (copy_from_user(port->tty->termios, user_arg,
831 						sizeof(struct ktermios))) {
832 				return -EFAULT;
833 			}
834 			oti6858_set_termios(port, NULL);
835 			return 0;
836 
837 		case TCFLSH:
838 			/* FIXME */
839 			return 0;
840 
841 		case TIOCMBIS:
842 			if (copy_from_user(&x, user_arg, sizeof(x)))
843 				return -EFAULT;
844 			return oti6858_tiocmset(port, NULL, x, 0);
845 
846 		case TIOCMBIC:
847 			if (copy_from_user(&x, user_arg, sizeof(x)))
848 				return -EFAULT;
849 			return oti6858_tiocmset(port, NULL, 0, x);
850 
851 		case TIOCGSERIAL:
852 			if (copy_to_user(user_arg, port->tty->termios,
853 						sizeof(struct ktermios))) {
854 				return -EFAULT;
855 			}
856                         return 0;
857 
858 		case TIOCSSERIAL:
859 			if (copy_from_user(port->tty->termios, user_arg,
860 						sizeof(struct ktermios))) {
861 				return -EFAULT;
862 			}
863 			oti6858_set_termios(port, NULL);
864 			return 0;
865 
866 		case TIOCMIWAIT:
867 			dbg("%s(): TIOCMIWAIT", __FUNCTION__);
868 			return wait_modem_info(port, arg);
869 
870 		default:
871 			dbg("%s(): 0x%04x not supported", __FUNCTION__, cmd);
872 			break;
873 	}
874 
875 	return -ENOIOCTLCMD;
876 }
877 
878 static void oti6858_break_ctl(struct usb_serial_port *port, int break_state)
879 {
880 	int state;
881 
882 	dbg("%s(port = %d)", __FUNCTION__, port->number);
883 
884 	state = (break_state == 0) ? 0 : 1;
885 	dbg("%s(): turning break %s", __FUNCTION__, state ? "on" : "off");
886 
887 	/* FIXME */
888 /*
889 	result = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
890 				  BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
891 				  0, NULL, 0, 100);
892 	if (result != 0)
893 		dbg("%s(): error sending break", __FUNCTION__);
894  */
895 }
896 
897 static void oti6858_shutdown(struct usb_serial *serial)
898 {
899 	struct oti6858_private *priv;
900 	int i;
901 
902 	dbg("%s()", __FUNCTION__);
903 
904 	for (i = 0; i < serial->num_ports; ++i) {
905 		priv = usb_get_serial_port_data(serial->port[i]);
906 		if (priv) {
907 			pl2303_buf_free(priv->buf);
908 			kfree(priv);
909 			usb_set_serial_port_data(serial->port[i], NULL);
910 		}
911 	}
912 }
913 
914 static void oti6858_read_int_callback(struct urb *urb)
915 {
916 	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
917 	struct oti6858_private *priv = usb_get_serial_port_data(port);
918 	int transient = 0, can_recv = 0, resubmit = 1;
919 	int status = urb->status;
920 
921 	dbg("%s(port = %d, status = %d)",
922 				__FUNCTION__, port->number, status);
923 
924 	switch (status) {
925 	case 0:
926 		/* success */
927 		break;
928 	case -ECONNRESET:
929 	case -ENOENT:
930 	case -ESHUTDOWN:
931 		/* this urb is terminated, clean up */
932 		dbg("%s(): urb shutting down with status: %d",
933 					__FUNCTION__, status);
934 		return;
935 	default:
936 		dbg("%s(): nonzero urb status received: %d",
937 					__FUNCTION__, status);
938 		break;
939 	}
940 
941 	if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
942 		struct oti6858_control_pkt *xs = urb->transfer_buffer;
943 		unsigned long flags;
944 
945 		spin_lock_irqsave(&priv->lock, flags);
946 
947 		if (!priv->transient) {
948 			if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
949 				if (xs->rx_bytes_avail == 0) {
950 					priv->transient = 4;
951 					priv->setup_done = 0;
952 					resubmit = 0;
953 					dbg("%s(): scheduling setup_line()",
954 					    __FUNCTION__);
955 					schedule_delayed_work(&priv->delayed_setup_work, 0);
956 				}
957 			}
958 		} else {
959 			if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
960 				priv->transient = 0;
961 			} else if (!priv->setup_done) {
962 				resubmit = 0;
963 			} else if (--priv->transient == 0) {
964 				if (xs->rx_bytes_avail == 0) {
965 					priv->transient = 4;
966 					priv->setup_done = 0;
967 					resubmit = 0;
968 					dbg("%s(): scheduling setup_line()",
969 					    __FUNCTION__);
970 					schedule_delayed_work(&priv->delayed_setup_work, 0);
971 				}
972 			}
973 		}
974 
975 		if (!priv->transient) {
976 			if (xs->pin_state != priv->status.pin_state)
977 				wake_up_interruptible(&priv->intr_wait);
978 			memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
979 		}
980 
981 		if (!priv->transient && xs->rx_bytes_avail != 0) {
982 			can_recv = xs->rx_bytes_avail;
983 			priv->flags.read_urb_in_use = 1;
984 		}
985 
986 		transient = priv->transient;
987 		spin_unlock_irqrestore(&priv->lock, flags);
988 	}
989 
990 	if (can_recv) {
991 		int result;
992 
993 		port->read_urb->dev = port->serial->dev;
994 		result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
995 		if (result != 0) {
996 			priv->flags.read_urb_in_use = 0;
997 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
998 					" error %d\n", __FUNCTION__, result);
999 		} else {
1000 			resubmit = 0;
1001 		}
1002 	} else if (!transient) {
1003 		unsigned long flags;
1004 
1005 		spin_lock_irqsave(&priv->lock, flags);
1006 		if (priv->flags.write_urb_in_use == 0
1007 				&& pl2303_buf_data_avail(priv->buf) != 0) {
1008 			schedule_delayed_work(&priv->delayed_write_work,0);
1009 			resubmit = 0;
1010 		}
1011 		spin_unlock_irqrestore(&priv->lock, flags);
1012 	}
1013 
1014 	if (resubmit) {
1015 		int result;
1016 
1017 //		dbg("%s(): submitting interrupt urb", __FUNCTION__);
1018 		urb->dev = port->serial->dev;
1019 		result = usb_submit_urb(urb, GFP_ATOMIC);
1020 		if (result != 0) {
1021 			dev_err(&urb->dev->dev,
1022 					"%s(): usb_submit_urb() failed with"
1023 					" error %d\n", __FUNCTION__, result);
1024 		}
1025 	}
1026 }
1027 
1028 static void oti6858_read_bulk_callback(struct urb *urb)
1029 {
1030 	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
1031 	struct oti6858_private *priv = usb_get_serial_port_data(port);
1032 	struct tty_struct *tty;
1033 	unsigned char *data = urb->transfer_buffer;
1034 	unsigned long flags;
1035 	int i, result;
1036 	int status = urb->status;
1037 	char tty_flag;
1038 
1039 	dbg("%s(port = %d, status = %d)",
1040 				__FUNCTION__, port->number, status);
1041 
1042 	spin_lock_irqsave(&priv->lock, flags);
1043 	priv->flags.read_urb_in_use = 0;
1044 	spin_unlock_irqrestore(&priv->lock, flags);
1045 
1046 	if (status != 0) {
1047 		if (!port->open_count) {
1048 			dbg("%s(): port is closed, exiting", __FUNCTION__);
1049 			return;
1050 		}
1051 		/*
1052 		if (status == -EPROTO) {
1053 			// PL2303 mysteriously fails with -EPROTO reschedule the read
1054 			dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
1055 			result = usb_submit_urb(urb, GFP_ATOMIC);
1056 			if (result)
1057 				dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
1058 			return;
1059 		}
1060 		*/
1061 		dbg("%s(): unable to handle the error, exiting", __FUNCTION__);
1062 		return;
1063 	}
1064 
1065 	// get tty_flag from status
1066 	tty_flag = TTY_NORMAL;
1067 
1068 /* FIXME: probably, errors will be signalled using interrupt pipe! */
1069 /*
1070 	// break takes precedence over parity,
1071 	// which takes precedence over framing errors
1072 	if (status & UART_BREAK_ERROR )
1073 		tty_flag = TTY_BREAK;
1074 	else if (status & UART_PARITY_ERROR)
1075 		tty_flag = TTY_PARITY;
1076 	else if (status & UART_FRAME_ERROR)
1077 		tty_flag = TTY_FRAME;
1078 	dbg("%s - tty_flag = %d", __FUNCTION__, tty_flag);
1079 */
1080 
1081 	tty = port->tty;
1082 	if (tty != NULL && urb->actual_length > 0) {
1083 		tty_buffer_request_room(tty, urb->actual_length);
1084 		for (i = 0; i < urb->actual_length; ++i)
1085 			tty_insert_flip_char(tty, data[i], tty_flag);
1086 		tty_flip_buffer_push(tty);
1087 	}
1088 
1089 	// schedule the interrupt urb if we are still open */
1090 	if (port->open_count != 0) {
1091 		port->interrupt_in_urb->dev = port->serial->dev;
1092 		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1093 		if (result != 0) {
1094 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1095 					" error %d\n", __FUNCTION__, result);
1096 		}
1097 	}
1098 }
1099 
1100 static void oti6858_write_bulk_callback(struct urb *urb)
1101 {
1102 	struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
1103 	struct oti6858_private *priv = usb_get_serial_port_data(port);
1104 	int status = urb->status;
1105 	int result;
1106 
1107 	dbg("%s(port = %d, status = %d)",
1108 				__FUNCTION__, port->number, status);
1109 
1110 	switch (status) {
1111 	case 0:
1112 		/* success */
1113 		break;
1114 	case -ECONNRESET:
1115 	case -ENOENT:
1116 	case -ESHUTDOWN:
1117 		/* this urb is terminated, clean up */
1118 		dbg("%s(): urb shutting down with status: %d",
1119 					__FUNCTION__, status);
1120 		priv->flags.write_urb_in_use = 0;
1121 		return;
1122 	default:
1123 		/* error in the urb, so we have to resubmit it */
1124 		dbg("%s(): nonzero write bulk status received: %d",
1125 					__FUNCTION__, status);
1126 		dbg("%s(): overflow in write", __FUNCTION__);
1127 
1128 		port->write_urb->transfer_buffer_length = 1;
1129 		port->write_urb->dev = port->serial->dev;
1130 		result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
1131 		if (result) {
1132 			dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1133 					" error %d\n", __FUNCTION__, result);
1134 		} else {
1135 			return;
1136 		}
1137 	}
1138 
1139 	priv->flags.write_urb_in_use = 0;
1140 
1141 	// schedule the interrupt urb if we are still open */
1142 	port->interrupt_in_urb->dev = port->serial->dev;
1143 	dbg("%s(): submitting interrupt urb", __FUNCTION__);
1144 	result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1145 	if (result != 0) {
1146 		dev_err(&port->dev, "%s(): failed submitting int urb,"
1147 					" error %d\n", __FUNCTION__, result);
1148 	}
1149 }
1150 
1151 
1152 /*
1153  * pl2303_buf_alloc
1154  *
1155  * Allocate a circular buffer and all associated memory.
1156  */
1157 static struct pl2303_buf *pl2303_buf_alloc(unsigned int size)
1158 {
1159 	struct pl2303_buf *pb;
1160 
1161 	if (size == 0)
1162 		return NULL;
1163 
1164 	pb = (struct pl2303_buf *)kmalloc(sizeof(struct pl2303_buf), GFP_KERNEL);
1165 	if (pb == NULL)
1166 		return NULL;
1167 
1168 	pb->buf_buf = kmalloc(size, GFP_KERNEL);
1169 	if (pb->buf_buf == NULL) {
1170 		kfree(pb);
1171 		return NULL;
1172 	}
1173 
1174 	pb->buf_size = size;
1175 	pb->buf_get = pb->buf_put = pb->buf_buf;
1176 
1177 	return pb;
1178 }
1179 
1180 /*
1181  * pl2303_buf_free
1182  *
1183  * Free the buffer and all associated memory.
1184  */
1185 static void pl2303_buf_free(struct pl2303_buf *pb)
1186 {
1187 	if (pb) {
1188 		kfree(pb->buf_buf);
1189 		kfree(pb);
1190 	}
1191 }
1192 
1193 /*
1194  * pl2303_buf_clear
1195  *
1196  * Clear out all data in the circular buffer.
1197  */
1198 static void pl2303_buf_clear(struct pl2303_buf *pb)
1199 {
1200 	if (pb != NULL) {
1201 		/* equivalent to a get of all data available */
1202 		pb->buf_get = pb->buf_put;
1203 	}
1204 }
1205 
1206 /*
1207  * pl2303_buf_data_avail
1208  *
1209  * Return the number of bytes of data available in the circular
1210  * buffer.
1211  */
1212 static unsigned int pl2303_buf_data_avail(struct pl2303_buf *pb)
1213 {
1214 	if (pb == NULL)
1215 		return 0;
1216 	return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
1217 }
1218 
1219 /*
1220  * pl2303_buf_space_avail
1221  *
1222  * Return the number of bytes of space available in the circular
1223  * buffer.
1224  */
1225 static unsigned int pl2303_buf_space_avail(struct pl2303_buf *pb)
1226 {
1227 	if (pb == NULL)
1228 		return 0;
1229 	return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
1230 }
1231 
1232 /*
1233  * pl2303_buf_put
1234  *
1235  * Copy data data from a user buffer and put it into the circular buffer.
1236  * Restrict to the amount of space available.
1237  *
1238  * Return the number of bytes copied.
1239  */
1240 static unsigned int pl2303_buf_put(struct pl2303_buf *pb, const char *buf,
1241 					unsigned int count)
1242 {
1243 	unsigned int len;
1244 
1245 	if (pb == NULL)
1246 		return 0;
1247 
1248 	len  = pl2303_buf_space_avail(pb);
1249 	if (count > len)
1250 		count = len;
1251 
1252 	if (count == 0)
1253 		return 0;
1254 
1255 	len = pb->buf_buf + pb->buf_size - pb->buf_put;
1256 	if (count > len) {
1257 		memcpy(pb->buf_put, buf, len);
1258 		memcpy(pb->buf_buf, buf+len, count - len);
1259 		pb->buf_put = pb->buf_buf + count - len;
1260 	} else {
1261 		memcpy(pb->buf_put, buf, count);
1262 		if (count < len)
1263 			pb->buf_put += count;
1264 		else /* count == len */
1265 			pb->buf_put = pb->buf_buf;
1266 	}
1267 
1268 	return count;
1269 }
1270 
1271 /*
1272  * pl2303_buf_get
1273  *
1274  * Get data from the circular buffer and copy to the given buffer.
1275  * Restrict to the amount of data available.
1276  *
1277  * Return the number of bytes copied.
1278  */
1279 static unsigned int pl2303_buf_get(struct pl2303_buf *pb, char *buf,
1280 					unsigned int count)
1281 {
1282 	unsigned int len;
1283 
1284 	if (pb == NULL)
1285 		return 0;
1286 
1287 	len = pl2303_buf_data_avail(pb);
1288 	if (count > len)
1289 		count = len;
1290 
1291 	if (count == 0)
1292 		return 0;
1293 
1294 	len = pb->buf_buf + pb->buf_size - pb->buf_get;
1295 	if (count > len) {
1296 		memcpy(buf, pb->buf_get, len);
1297 		memcpy(buf+len, pb->buf_buf, count - len);
1298 		pb->buf_get = pb->buf_buf + count - len;
1299 	} else {
1300 		memcpy(buf, pb->buf_get, count);
1301 		if (count < len)
1302 			pb->buf_get += count;
1303 		else /* count == len */
1304 			pb->buf_get = pb->buf_buf;
1305 	}
1306 
1307 	return count;
1308 }
1309 
1310 /* module description and (de)initialization */
1311 
1312 static int __init oti6858_init(void)
1313 {
1314 	int retval;
1315 
1316 	if ((retval = usb_serial_register(&oti6858_device)) == 0) {
1317 		if ((retval = usb_register(&oti6858_driver)) != 0)
1318 			usb_serial_deregister(&oti6858_device);
1319 		else
1320 			return 0;
1321 	}
1322 
1323 	return retval;
1324 }
1325 
1326 static void __exit oti6858_exit(void)
1327 {
1328 	usb_deregister(&oti6858_driver);
1329 	usb_serial_deregister(&oti6858_device);
1330 }
1331 
1332 module_init(oti6858_init);
1333 module_exit(oti6858_exit);
1334 
1335 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1336 MODULE_AUTHOR(OTI6858_AUTHOR);
1337 MODULE_VERSION(OTI6858_VERSION);
1338 MODULE_LICENSE("GPL");
1339 
1340 module_param(debug, bool, S_IRUGO | S_IWUSR);
1341 MODULE_PARM_DESC(debug, "enable debug output");
1342 
1343