Pull thermal into release branch
[linux-2.6] / drivers / usb / serial / oti6858.c
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\n", __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 TCFLSH:
821                         /* FIXME */
822                         return 0;
823
824                 case TIOCMBIS:
825                         if (copy_from_user(&x, user_arg, sizeof(x)))
826                                 return -EFAULT;
827                         return oti6858_tiocmset(port, NULL, x, 0);
828
829                 case TIOCMBIC:
830                         if (copy_from_user(&x, user_arg, sizeof(x)))
831                                 return -EFAULT;
832                         return oti6858_tiocmset(port, NULL, 0, x);
833
834                 case TIOCGSERIAL:
835                         if (copy_to_user(user_arg, port->tty->termios,
836                                                 sizeof(struct ktermios))) {
837                                 return -EFAULT;
838                         }
839                         return 0;
840
841                 case TIOCSSERIAL:
842                         if (copy_from_user(port->tty->termios, user_arg,
843                                                 sizeof(struct ktermios))) {
844                                 return -EFAULT;
845                         }
846                         oti6858_set_termios(port, NULL);
847                         return 0;
848
849                 case TIOCMIWAIT:
850                         dbg("%s(): TIOCMIWAIT", __FUNCTION__);
851                         return wait_modem_info(port, arg);
852
853                 default:
854                         dbg("%s(): 0x%04x not supported", __FUNCTION__, cmd);
855                         break;
856         }
857
858         return -ENOIOCTLCMD;
859 }
860
861 static void oti6858_break_ctl(struct usb_serial_port *port, int break_state)
862 {
863         int state;
864
865         dbg("%s(port = %d)", __FUNCTION__, port->number);
866
867         state = (break_state == 0) ? 0 : 1;
868         dbg("%s(): turning break %s", __FUNCTION__, state ? "on" : "off");
869
870         /* FIXME */
871 /*
872         result = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
873                                   BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
874                                   0, NULL, 0, 100);
875         if (result != 0)
876                 dbg("%s(): error sending break", __FUNCTION__);
877  */
878 }
879
880 static void oti6858_shutdown(struct usb_serial *serial)
881 {
882         struct oti6858_private *priv;
883         int i;
884
885         dbg("%s()", __FUNCTION__);
886
887         for (i = 0; i < serial->num_ports; ++i) {
888                 priv = usb_get_serial_port_data(serial->port[i]);
889                 if (priv) {
890                         pl2303_buf_free(priv->buf);
891                         kfree(priv);
892                         usb_set_serial_port_data(serial->port[i], NULL);
893                 }
894         }
895 }
896
897 static void oti6858_read_int_callback(struct urb *urb)
898 {
899         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
900         struct oti6858_private *priv = usb_get_serial_port_data(port);
901         int transient = 0, can_recv = 0, resubmit = 1;
902         int status = urb->status;
903
904         dbg("%s(port = %d, status = %d)",
905                                 __FUNCTION__, port->number, status);
906
907         switch (status) {
908         case 0:
909                 /* success */
910                 break;
911         case -ECONNRESET:
912         case -ENOENT:
913         case -ESHUTDOWN:
914                 /* this urb is terminated, clean up */
915                 dbg("%s(): urb shutting down with status: %d",
916                                         __FUNCTION__, status);
917                 return;
918         default:
919                 dbg("%s(): nonzero urb status received: %d",
920                                         __FUNCTION__, status);
921                 break;
922         }
923
924         if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
925                 struct oti6858_control_pkt *xs = urb->transfer_buffer;
926                 unsigned long flags;
927
928                 spin_lock_irqsave(&priv->lock, flags);
929
930                 if (!priv->transient) {
931                         if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
932                                 if (xs->rx_bytes_avail == 0) {
933                                         priv->transient = 4;
934                                         priv->setup_done = 0;
935                                         resubmit = 0;
936                                         dbg("%s(): scheduling setup_line()",
937                                             __FUNCTION__);
938                                         schedule_delayed_work(&priv->delayed_setup_work, 0);
939                                 }
940                         }
941                 } else {
942                         if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
943                                 priv->transient = 0;
944                         } else if (!priv->setup_done) {
945                                 resubmit = 0;
946                         } else if (--priv->transient == 0) {
947                                 if (xs->rx_bytes_avail == 0) {
948                                         priv->transient = 4;
949                                         priv->setup_done = 0;
950                                         resubmit = 0;
951                                         dbg("%s(): scheduling setup_line()",
952                                             __FUNCTION__);
953                                         schedule_delayed_work(&priv->delayed_setup_work, 0);
954                                 }
955                         }
956                 }
957
958                 if (!priv->transient) {
959                         if (xs->pin_state != priv->status.pin_state)
960                                 wake_up_interruptible(&priv->intr_wait);
961                         memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
962                 }
963
964                 if (!priv->transient && xs->rx_bytes_avail != 0) {
965                         can_recv = xs->rx_bytes_avail;
966                         priv->flags.read_urb_in_use = 1;
967                 }
968
969                 transient = priv->transient;
970                 spin_unlock_irqrestore(&priv->lock, flags);
971         }
972
973         if (can_recv) {
974                 int result;
975
976                 port->read_urb->dev = port->serial->dev;
977                 result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
978                 if (result != 0) {
979                         priv->flags.read_urb_in_use = 0;
980                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
981                                         " error %d\n", __FUNCTION__, result);
982                 } else {
983                         resubmit = 0;
984                 }
985         } else if (!transient) {
986                 unsigned long flags;
987
988                 spin_lock_irqsave(&priv->lock, flags);
989                 if (priv->flags.write_urb_in_use == 0
990                                 && pl2303_buf_data_avail(priv->buf) != 0) {
991                         schedule_delayed_work(&priv->delayed_write_work,0);
992                         resubmit = 0;
993                 }
994                 spin_unlock_irqrestore(&priv->lock, flags);
995         }
996
997         if (resubmit) {
998                 int result;
999
1000 //              dbg("%s(): submitting interrupt urb", __FUNCTION__);
1001                 urb->dev = port->serial->dev;
1002                 result = usb_submit_urb(urb, GFP_ATOMIC);
1003                 if (result != 0) {
1004                         dev_err(&urb->dev->dev,
1005                                         "%s(): usb_submit_urb() failed with"
1006                                         " error %d\n", __FUNCTION__, result);
1007                 }
1008         }
1009 }
1010
1011 static void oti6858_read_bulk_callback(struct urb *urb)
1012 {
1013         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
1014         struct oti6858_private *priv = usb_get_serial_port_data(port);
1015         struct tty_struct *tty;
1016         unsigned char *data = urb->transfer_buffer;
1017         unsigned long flags;
1018         int i, result;
1019         int status = urb->status;
1020         char tty_flag;
1021
1022         dbg("%s(port = %d, status = %d)",
1023                                 __FUNCTION__, port->number, status);
1024
1025         spin_lock_irqsave(&priv->lock, flags);
1026         priv->flags.read_urb_in_use = 0;
1027         spin_unlock_irqrestore(&priv->lock, flags);
1028
1029         if (status != 0) {
1030                 if (!port->open_count) {
1031                         dbg("%s(): port is closed, exiting", __FUNCTION__);
1032                         return;
1033                 }
1034                 /*
1035                 if (status == -EPROTO) {
1036                         // PL2303 mysteriously fails with -EPROTO reschedule the read
1037                         dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
1038                         result = usb_submit_urb(urb, GFP_ATOMIC);
1039                         if (result)
1040                                 dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
1041                         return;
1042                 }
1043                 */
1044                 dbg("%s(): unable to handle the error, exiting", __FUNCTION__);
1045                 return;
1046         }
1047
1048         // get tty_flag from status
1049         tty_flag = TTY_NORMAL;
1050
1051 /* FIXME: probably, errors will be signalled using interrupt pipe! */
1052 /*
1053         // break takes precedence over parity,
1054         // which takes precedence over framing errors
1055         if (status & UART_BREAK_ERROR )
1056                 tty_flag = TTY_BREAK;
1057         else if (status & UART_PARITY_ERROR)
1058                 tty_flag = TTY_PARITY;
1059         else if (status & UART_FRAME_ERROR)
1060                 tty_flag = TTY_FRAME;
1061         dbg("%s - tty_flag = %d", __FUNCTION__, tty_flag);
1062 */
1063
1064         tty = port->tty;
1065         if (tty != NULL && urb->actual_length > 0) {
1066                 tty_buffer_request_room(tty, urb->actual_length);
1067                 for (i = 0; i < urb->actual_length; ++i)
1068                         tty_insert_flip_char(tty, data[i], tty_flag);
1069                 tty_flip_buffer_push(tty);
1070         }
1071
1072         // schedule the interrupt urb if we are still open */
1073         if (port->open_count != 0) {
1074                 port->interrupt_in_urb->dev = port->serial->dev;
1075                 result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1076                 if (result != 0) {
1077                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1078                                         " error %d\n", __FUNCTION__, result);
1079                 }
1080         }
1081 }
1082
1083 static void oti6858_write_bulk_callback(struct urb *urb)
1084 {
1085         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
1086         struct oti6858_private *priv = usb_get_serial_port_data(port);
1087         int status = urb->status;
1088         int result;
1089
1090         dbg("%s(port = %d, status = %d)",
1091                                 __FUNCTION__, port->number, status);
1092
1093         switch (status) {
1094         case 0:
1095                 /* success */
1096                 break;
1097         case -ECONNRESET:
1098         case -ENOENT:
1099         case -ESHUTDOWN:
1100                 /* this urb is terminated, clean up */
1101                 dbg("%s(): urb shutting down with status: %d",
1102                                         __FUNCTION__, status);
1103                 priv->flags.write_urb_in_use = 0;
1104                 return;
1105         default:
1106                 /* error in the urb, so we have to resubmit it */
1107                 dbg("%s(): nonzero write bulk status received: %d",
1108                                         __FUNCTION__, status);
1109                 dbg("%s(): overflow in write", __FUNCTION__);
1110
1111                 port->write_urb->transfer_buffer_length = 1;
1112                 port->write_urb->dev = port->serial->dev;
1113                 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
1114                 if (result) {
1115                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1116                                         " error %d\n", __FUNCTION__, result);
1117                 } else {
1118                         return;
1119                 }
1120         }
1121
1122         priv->flags.write_urb_in_use = 0;
1123
1124         // schedule the interrupt urb if we are still open */
1125         port->interrupt_in_urb->dev = port->serial->dev;
1126         dbg("%s(): submitting interrupt urb", __FUNCTION__);
1127         result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1128         if (result != 0) {
1129                 dev_err(&port->dev, "%s(): failed submitting int urb,"
1130                                         " error %d\n", __FUNCTION__, result);
1131         }
1132 }
1133
1134
1135 /*
1136  * pl2303_buf_alloc
1137  *
1138  * Allocate a circular buffer and all associated memory.
1139  */
1140 static struct pl2303_buf *pl2303_buf_alloc(unsigned int size)
1141 {
1142         struct pl2303_buf *pb;
1143
1144         if (size == 0)
1145                 return NULL;
1146
1147         pb = kmalloc(sizeof(struct pl2303_buf), GFP_KERNEL);
1148         if (pb == NULL)
1149                 return NULL;
1150
1151         pb->buf_buf = kmalloc(size, GFP_KERNEL);
1152         if (pb->buf_buf == NULL) {
1153                 kfree(pb);
1154                 return NULL;
1155         }
1156
1157         pb->buf_size = size;
1158         pb->buf_get = pb->buf_put = pb->buf_buf;
1159
1160         return pb;
1161 }
1162
1163 /*
1164  * pl2303_buf_free
1165  *
1166  * Free the buffer and all associated memory.
1167  */
1168 static void pl2303_buf_free(struct pl2303_buf *pb)
1169 {
1170         if (pb) {
1171                 kfree(pb->buf_buf);
1172                 kfree(pb);
1173         }
1174 }
1175
1176 /*
1177  * pl2303_buf_clear
1178  *
1179  * Clear out all data in the circular buffer.
1180  */
1181 static void pl2303_buf_clear(struct pl2303_buf *pb)
1182 {
1183         if (pb != NULL) {
1184                 /* equivalent to a get of all data available */
1185                 pb->buf_get = pb->buf_put;
1186         }
1187 }
1188
1189 /*
1190  * pl2303_buf_data_avail
1191  *
1192  * Return the number of bytes of data available in the circular
1193  * buffer.
1194  */
1195 static unsigned int pl2303_buf_data_avail(struct pl2303_buf *pb)
1196 {
1197         if (pb == NULL)
1198                 return 0;
1199         return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
1200 }
1201
1202 /*
1203  * pl2303_buf_space_avail
1204  *
1205  * Return the number of bytes of space available in the circular
1206  * buffer.
1207  */
1208 static unsigned int pl2303_buf_space_avail(struct pl2303_buf *pb)
1209 {
1210         if (pb == NULL)
1211                 return 0;
1212         return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
1213 }
1214
1215 /*
1216  * pl2303_buf_put
1217  *
1218  * Copy data data from a user buffer and put it into the circular buffer.
1219  * Restrict to the amount of space available.
1220  *
1221  * Return the number of bytes copied.
1222  */
1223 static unsigned int pl2303_buf_put(struct pl2303_buf *pb, const char *buf,
1224                                         unsigned int count)
1225 {
1226         unsigned int len;
1227
1228         if (pb == NULL)
1229                 return 0;
1230
1231         len  = pl2303_buf_space_avail(pb);
1232         if (count > len)
1233                 count = len;
1234
1235         if (count == 0)
1236                 return 0;
1237
1238         len = pb->buf_buf + pb->buf_size - pb->buf_put;
1239         if (count > len) {
1240                 memcpy(pb->buf_put, buf, len);
1241                 memcpy(pb->buf_buf, buf+len, count - len);
1242                 pb->buf_put = pb->buf_buf + count - len;
1243         } else {
1244                 memcpy(pb->buf_put, buf, count);
1245                 if (count < len)
1246                         pb->buf_put += count;
1247                 else /* count == len */
1248                         pb->buf_put = pb->buf_buf;
1249         }
1250
1251         return count;
1252 }
1253
1254 /*
1255  * pl2303_buf_get
1256  *
1257  * Get data from the circular buffer and copy to the given buffer.
1258  * Restrict to the amount of data available.
1259  *
1260  * Return the number of bytes copied.
1261  */
1262 static unsigned int pl2303_buf_get(struct pl2303_buf *pb, char *buf,
1263                                         unsigned int count)
1264 {
1265         unsigned int len;
1266
1267         if (pb == NULL)
1268                 return 0;
1269
1270         len = pl2303_buf_data_avail(pb);
1271         if (count > len)
1272                 count = len;
1273
1274         if (count == 0)
1275                 return 0;
1276
1277         len = pb->buf_buf + pb->buf_size - pb->buf_get;
1278         if (count > len) {
1279                 memcpy(buf, pb->buf_get, len);
1280                 memcpy(buf+len, pb->buf_buf, count - len);
1281                 pb->buf_get = pb->buf_buf + count - len;
1282         } else {
1283                 memcpy(buf, pb->buf_get, count);
1284                 if (count < len)
1285                         pb->buf_get += count;
1286                 else /* count == len */
1287                         pb->buf_get = pb->buf_buf;
1288         }
1289
1290         return count;
1291 }
1292
1293 /* module description and (de)initialization */
1294
1295 static int __init oti6858_init(void)
1296 {
1297         int retval;
1298
1299         if ((retval = usb_serial_register(&oti6858_device)) == 0) {
1300                 if ((retval = usb_register(&oti6858_driver)) != 0)
1301                         usb_serial_deregister(&oti6858_device);
1302                 else
1303                         return 0;
1304         }
1305
1306         return retval;
1307 }
1308
1309 static void __exit oti6858_exit(void)
1310 {
1311         usb_deregister(&oti6858_driver);
1312         usb_serial_deregister(&oti6858_device);
1313 }
1314
1315 module_init(oti6858_init);
1316 module_exit(oti6858_exit);
1317
1318 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1319 MODULE_AUTHOR(OTI6858_AUTHOR);
1320 MODULE_VERSION(OTI6858_VERSION);
1321 MODULE_LICENSE("GPL");
1322
1323 module_param(debug, bool, S_IRUGO | S_IWUSR);
1324 MODULE_PARM_DESC(debug, "enable debug output");
1325