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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 oti6858_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 oti6858_buf *oti6858_buf_alloc(unsigned int size);
165 static void oti6858_buf_free(struct oti6858_buf *pb);
166 static void oti6858_buf_clear(struct oti6858_buf *pb);
167 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb);
168 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb);
169 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
170                                         unsigned int count);
171 static unsigned int oti6858_buf_get(struct oti6858_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 oti6858_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 = oti6858_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         oti6858_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 = oti6858_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                 oti6858_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 = oti6858_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 = oti6858_buf_space_avail(priv->buf);
429         spin_unlock_irqrestore(&priv->lock, flags);
430 
431         return room;
432 }
433 
434 static int oti6858_chars_in_buffer(struct 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 = oti6858_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                 port->tty->termios->c_ispeed = 38400;
472                 port->tty->termios->c_ospeed = 38400;
473         }
474         spin_unlock_irqrestore(&priv->lock, flags);
475 
476         cflag = port->tty->termios->c_cflag;
477 
478         spin_lock_irqsave(&priv->lock, flags);
479         divisor = priv->pending_setup.divisor;
480         frame_fmt = priv->pending_setup.frame_fmt;
481         control = priv->pending_setup.control;
482         spin_unlock_irqrestore(&priv->lock, flags);
483 
484         frame_fmt &= ~FMT_DATA_BITS_MASK;
485         switch (cflag & CSIZE) {
486                 case CS5:
487                         frame_fmt |= FMT_DATA_BITS_5;
488                         break;
489                 case CS6:
490                         frame_fmt |= FMT_DATA_BITS_6;
491                         break;
492                 case CS7:
493                         frame_fmt |= FMT_DATA_BITS_7;
494                         break;
495                 default:
496                 case CS8:
497                         frame_fmt |= FMT_DATA_BITS_8;
498                         break;
499         }
500 
501         /* manufacturer claims that this device can work with baud rates
502          * up to 3 Mbps; I've tested it only on 115200 bps, so I can't
503          * guarantee that any other baud rate will work (especially
504          * the higher ones)
505          */
506         br = tty_get_baud_rate(port->tty);
507         if (br == 0) {
508                 divisor = 0;
509         } else {
510                 int real_br;
511                 br = min(br, OTI6858_MAX_BAUD_RATE);
512 
513                 divisor = (96000000 + 8 * br) / (16 * br);
514                 real_br = 96000000 / (16 * divisor);
515                 divisor = cpu_to_le16(divisor);
516                 tty_encode_baud_rate(port->tty, real_br, real_br);
517         }
518 
519         frame_fmt &= ~FMT_STOP_BITS_MASK;
520         if ((cflag & CSTOPB) != 0) {
521                 frame_fmt |= FMT_STOP_BITS_2;
522         } else {
523                 frame_fmt |= FMT_STOP_BITS_1;
524         }
525 
526         frame_fmt &= ~FMT_PARITY_MASK;
527         if ((cflag & PARENB) != 0) {
528                 if ((cflag & PARODD) != 0) {
529                         frame_fmt |= FMT_PARITY_ODD;
530                 } else {
531                         frame_fmt |= FMT_PARITY_EVEN;
532                 }
533         } else {
534                 frame_fmt |= FMT_PARITY_NONE;
535         }
536 
537         control &= ~CONTROL_MASK;
538         if ((cflag & CRTSCTS) != 0)
539                 control |= (CONTROL_DTR_HIGH | CONTROL_RTS_HIGH);
540 
541         /* change control lines if we are switching to or from B0 */
542         /* FIXME:
543         spin_lock_irqsave(&priv->lock, flags);
544         control = priv->line_control;
545         if ((cflag & CBAUD) == B0)
546                 priv->line_control &= ~(CONTROL_DTR | CONTROL_RTS);
547         else
548                 priv->line_control |= (CONTROL_DTR | CONTROL_RTS);
549         if (control != priv->line_control) {
550                 control = priv->line_control;
551                 spin_unlock_irqrestore(&priv->lock, flags);
552                 set_control_lines(serial->dev, control);
553         } else {
554                 spin_unlock_irqrestore(&priv->lock, flags);
555         }
556         */
557 
558         spin_lock_irqsave(&priv->lock, flags);
559         if (divisor != priv->pending_setup.divisor
560                         || control != priv->pending_setup.control
561                         || frame_fmt != priv->pending_setup.frame_fmt) {
562                 priv->pending_setup.divisor = divisor;
563                 priv->pending_setup.control = control;
564                 priv->pending_setup.frame_fmt = frame_fmt;
565         }
566         spin_unlock_irqrestore(&priv->lock, flags);
567 }
568 
569 static int oti6858_open(struct usb_serial_port *port, struct file *filp)
570 {
571         struct oti6858_private *priv = usb_get_serial_port_data(port);
572         struct ktermios tmp_termios;
573         struct usb_serial *serial = port->serial;
574         struct oti6858_control_pkt *buf;
575         unsigned long flags;
576         int result;
577 
578         dbg("%s(port = %d)", __FUNCTION__, port->number);
579 
580         usb_clear_halt(serial->dev, port->write_urb->pipe);
581         usb_clear_halt(serial->dev, port->read_urb->pipe);
582 
583         if (port->open_count != 1)
584                 return 0;
585 
586         if ((buf = kmalloc(OTI6858_CTRL_PKT_SIZE, GFP_KERNEL)) == NULL) {
587                 dev_err(&port->dev, "%s(): out of memory!\n", __FUNCTION__);
588                 return -ENOMEM;
589         }
590 
591         result = usb_control_msg(serial->dev, usb_rcvctrlpipe(serial->dev, 0),
592                                 OTI6858_REQ_T_GET_STATUS,
593                                 OTI6858_REQ_GET_STATUS,
594                                 0, 0,
595                                 buf, OTI6858_CTRL_PKT_SIZE,
596                                 100);
597         if (result != OTI6858_CTRL_PKT_SIZE) {
598                 /* assume default (after power-on reset) values */
599                 buf->divisor = cpu_to_le16(0x009c);     /* 38400 bps */
600                 buf->frame_fmt = 0x03;  /* 8N1 */
601                 buf->something = 0x43;
602                 buf->control = 0x4c;    /* DTR, RTS */
603                 buf->tx_status = 0x00;
604                 buf->pin_state = 0x5b;  /* RTS, CTS, DSR, DTR, RI, DCD */
605                 buf->rx_bytes_avail = 0x00;
606         }
607 
608         spin_lock_irqsave(&priv->lock, flags);
609         memcpy(&priv->status, buf, OTI6858_CTRL_PKT_SIZE);
610         priv->pending_setup.divisor = buf->divisor;
611         priv->pending_setup.frame_fmt = buf->frame_fmt;
612         priv->pending_setup.control = buf->control;
613         spin_unlock_irqrestore(&priv->lock, flags);
614         kfree(buf);
615 
616         dbg("%s(): submitting interrupt urb", __FUNCTION__);
617         port->interrupt_in_urb->dev = serial->dev;
618         result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
619         if (result != 0) {
620                 dev_err(&port->dev, "%s(): usb_submit_urb() failed"
621                                " with error %d\n", __FUNCTION__, result);
622                 oti6858_close(port, NULL);
623                 return -EPROTO;
624         }
625 
626         /* setup termios */
627         if (port->tty)
628                 oti6858_set_termios(port, &tmp_termios);
629 
630         return 0;
631 }
632 
633 static void oti6858_close(struct usb_serial_port *port, struct file *filp)
634 {
635         struct oti6858_private *priv = usb_get_serial_port_data(port);
636         unsigned long flags;
637         long timeout;
638         wait_queue_t wait;
639 
640         dbg("%s(port = %d)", __FUNCTION__, port->number);
641 
642         /* wait for data to drain from the buffer */
643         spin_lock_irqsave(&priv->lock, flags);
644         timeout = 30 * HZ;      /* PL2303_CLOSING_WAIT */
645         init_waitqueue_entry(&wait, current);
646         add_wait_queue(&port->tty->write_wait, &wait);
647         dbg("%s(): entering wait loop", __FUNCTION__);
648         for (;;) {
649                 set_current_state(TASK_INTERRUPTIBLE);
650                 if (oti6858_buf_data_avail(priv->buf) == 0
651                 || timeout == 0 || signal_pending(current)
652                 || port->serial->disconnected)
653                         break;
654                 spin_unlock_irqrestore(&priv->lock, flags);
655                 timeout = schedule_timeout(timeout);
656                 spin_lock_irqsave(&priv->lock, flags);
657         }
658         set_current_state(TASK_RUNNING);
659         remove_wait_queue(&port->tty->write_wait, &wait);
660         dbg("%s(): after wait loop", __FUNCTION__);
661 
662         /* clear out any remaining data in the buffer */
663         oti6858_buf_clear(priv->buf);
664         spin_unlock_irqrestore(&priv->lock, flags);
665 
666         /* wait for characters to drain from the device */
667         /* (this is long enough for the entire 256 byte */
668         /* pl2303 hardware buffer to drain with no flow */
669         /* control for data rates of 1200 bps or more, */
670         /* for lower rates we should really know how much */
671         /* data is in the buffer to compute a delay */
672         /* that is not unnecessarily long) */
673         /* FIXME
674         bps = tty_get_baud_rate(port->tty);
675         if (bps > 1200)
676                 timeout = max((HZ*2560)/bps,HZ/10);
677         else
678         */
679                 timeout = 2*HZ;
680         schedule_timeout_interruptible(timeout);
681         dbg("%s(): after schedule_timeout_interruptible()", __FUNCTION__);
682 
683         /* cancel scheduled setup */
684         cancel_delayed_work(&priv->delayed_setup_work);
685         cancel_delayed_work(&priv->delayed_write_work);
686         flush_scheduled_work();
687 
688         /* shutdown our urbs */
689         dbg("%s(): shutting down urbs", __FUNCTION__);
690         usb_kill_urb(port->write_urb);
691         usb_kill_urb(port->read_urb);
692         usb_kill_urb(port->interrupt_in_urb);
693 
694         /*
695         if (port->tty && (port->tty->termios->c_cflag) & HUPCL) {
696                 // drop DTR and RTS
697                 spin_lock_irqsave(&priv->lock, flags);
698                 priv->pending_setup.control &= ~CONTROL_MASK;
699                 spin_unlock_irqrestore(&priv->lock, flags);
700         }
701         */
702 }
703 
704 static int oti6858_tiocmset(struct usb_serial_port *port, struct file *file,
705                                 unsigned int set, unsigned int clear)
706 {
707         struct oti6858_private *priv = usb_get_serial_port_data(port);
708         unsigned long flags;
709         u8 control;
710 
711         dbg("%s(port = %d, set = 0x%08x, clear = 0x%08x)",
712                                 __FUNCTION__, port->number, set, clear);
713 
714         if (!usb_get_intfdata(port->serial->interface))
715                 return -ENODEV;
716 
717         /* FIXME: check if this is correct (active high/low) */
718         spin_lock_irqsave(&priv->lock, flags);
719         control = priv->pending_setup.control;
720         if ((set & TIOCM_RTS) != 0)
721                 control |= CONTROL_RTS_HIGH;
722         if ((set & TIOCM_DTR) != 0)
723                 control |= CONTROL_DTR_HIGH;
724         if ((clear & TIOCM_RTS) != 0)
725                 control &= ~CONTROL_RTS_HIGH;
726         if ((clear & TIOCM_DTR) != 0)
727                 control &= ~CONTROL_DTR_HIGH;
728 
729         if (control != priv->pending_setup.control) {
730                 priv->pending_setup.control = control;
731         }
732         spin_unlock_irqrestore(&priv->lock, flags);
733 
734         return 0;
735 }
736 
737 static int oti6858_tiocmget(struct usb_serial_port *port, struct file *file)
738 {
739         struct oti6858_private *priv = usb_get_serial_port_data(port);
740         unsigned long flags;
741         unsigned pin_state;
742         unsigned result = 0;
743 
744         dbg("%s(port = %d)", __FUNCTION__, port->number);
745 
746         if (!usb_get_intfdata(port->serial->interface))
747                 return -ENODEV;
748 
749         spin_lock_irqsave(&priv->lock, flags);
750         pin_state = priv->status.pin_state & PIN_MASK;
751         spin_unlock_irqrestore(&priv->lock, flags);
752 
753         /* FIXME: check if this is correct (active high/low) */
754         if ((pin_state & PIN_RTS) != 0)
755                 result |= TIOCM_RTS;
756         if ((pin_state & PIN_CTS) != 0)
757                 result |= TIOCM_CTS;
758         if ((pin_state & PIN_DSR) != 0)
759                 result |= TIOCM_DSR;
760         if ((pin_state & PIN_DTR) != 0)
761                 result |= TIOCM_DTR;
762         if ((pin_state & PIN_RI) != 0)
763                 result |= TIOCM_RI;
764         if ((pin_state & PIN_DCD) != 0)
765                 result |= TIOCM_CD;
766 
767         dbg("%s() = 0x%08x", __FUNCTION__, result);
768 
769         return result;
770 }
771 
772 static int wait_modem_info(struct usb_serial_port *port, unsigned int arg)
773 {
774         struct oti6858_private *priv = usb_get_serial_port_data(port);
775         unsigned long flags;
776         unsigned int prev, status;
777         unsigned int changed;
778 
779         spin_lock_irqsave(&priv->lock, flags);
780         prev = priv->status.pin_state;
781         spin_unlock_irqrestore(&priv->lock, flags);
782 
783         while (1) {
784                 wait_event_interruptible(priv->intr_wait, priv->status.pin_state != prev);
785                 if (signal_pending(current))
786                         return -ERESTARTSYS;
787 
788                 spin_lock_irqsave(&priv->lock, flags);
789                 status = priv->status.pin_state & PIN_MASK;
790                 spin_unlock_irqrestore(&priv->lock, flags);
791 
792                 changed = prev ^ status;
793                 /* FIXME: check if this is correct (active high/low) */
794                 if (    ((arg & TIOCM_RNG) && (changed & PIN_RI)) ||
795                         ((arg & TIOCM_DSR) && (changed & PIN_DSR)) ||
796                         ((arg & TIOCM_CD)  && (changed & PIN_DCD)) ||
797                         ((arg & TIOCM_CTS) && (changed & PIN_CTS))) {
798                                 return 0;
799                 }
800                 prev = status;
801         }
802 
803         /* NOTREACHED */
804         return 0;
805 }
806 
807 static int oti6858_ioctl(struct usb_serial_port *port, struct file *file,
808                         unsigned int cmd, unsigned long arg)
809 {
810         void __user *user_arg = (void __user *) arg;
811         unsigned int x;
812 
813         dbg("%s(port = %d, cmd = 0x%04x, arg = 0x%08lx)",
814                                 __FUNCTION__, port->number, cmd, arg);
815 
816         switch (cmd) {
817                 case TCFLSH:
818                         /* FIXME */
819                         return 0;
820 
821                 case TIOCMBIS:
822                         if (copy_from_user(&x, user_arg, sizeof(x)))
823                                 return -EFAULT;
824                         return oti6858_tiocmset(port, NULL, x, 0);
825 
826                 case TIOCMBIC:
827                         if (copy_from_user(&x, user_arg, sizeof(x)))
828                                 return -EFAULT;
829                         return oti6858_tiocmset(port, NULL, 0, x);
830 
831                 case TIOCMIWAIT:
832                         dbg("%s(): TIOCMIWAIT", __FUNCTION__);
833                         return wait_modem_info(port, arg);
834 
835                 default:
836                         dbg("%s(): 0x%04x not supported", __FUNCTION__, cmd);
837                         break;
838         }
839 
840         return -ENOIOCTLCMD;
841 }
842 
843 static void oti6858_break_ctl(struct usb_serial_port *port, int break_state)
844 {
845         int state;
846 
847         dbg("%s(port = %d)", __FUNCTION__, port->number);
848 
849         state = (break_state == 0) ? 0 : 1;
850         dbg("%s(): turning break %s", __FUNCTION__, state ? "on" : "off");
851 
852         /* FIXME */
853 /*
854         result = usb_control_msg (serial->dev, usb_sndctrlpipe (serial->dev, 0),
855                                   BREAK_REQUEST, BREAK_REQUEST_TYPE, state,
856                                   0, NULL, 0, 100);
857         if (result != 0)
858                 dbg("%s(): error sending break", __FUNCTION__);
859  */
860 }
861 
862 static void oti6858_shutdown(struct usb_serial *serial)
863 {
864         struct oti6858_private *priv;
865         int i;
866 
867         dbg("%s()", __FUNCTION__);
868 
869         for (i = 0; i < serial->num_ports; ++i) {
870                 priv = usb_get_serial_port_data(serial->port[i]);
871                 if (priv) {
872                         oti6858_buf_free(priv->buf);
873                         kfree(priv);
874                         usb_set_serial_port_data(serial->port[i], NULL);
875                 }
876         }
877 }
878 
879 static void oti6858_read_int_callback(struct urb *urb)
880 {
881         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
882         struct oti6858_private *priv = usb_get_serial_port_data(port);
883         int transient = 0, can_recv = 0, resubmit = 1;
884         int status = urb->status;
885 
886         dbg("%s(port = %d, status = %d)",
887                                 __FUNCTION__, port->number, status);
888 
889         switch (status) {
890         case 0:
891                 /* success */
892                 break;
893         case -ECONNRESET:
894         case -ENOENT:
895         case -ESHUTDOWN:
896                 /* this urb is terminated, clean up */
897                 dbg("%s(): urb shutting down with status: %d",
898                                         __FUNCTION__, status);
899                 return;
900         default:
901                 dbg("%s(): nonzero urb status received: %d",
902                                         __FUNCTION__, status);
903                 break;
904         }
905 
906         if (status == 0 && urb->actual_length == OTI6858_CTRL_PKT_SIZE) {
907                 struct oti6858_control_pkt *xs = urb->transfer_buffer;
908                 unsigned long flags;
909 
910                 spin_lock_irqsave(&priv->lock, flags);
911 
912                 if (!priv->transient) {
913                         if (!OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
914                                 if (xs->rx_bytes_avail == 0) {
915                                         priv->transient = 4;
916                                         priv->setup_done = 0;
917                                         resubmit = 0;
918                                         dbg("%s(): scheduling setup_line()",
919                                             __FUNCTION__);
920                                         schedule_delayed_work(&priv->delayed_setup_work, 0);
921                                 }
922                         }
923                 } else {
924                         if (OTI6858_CTRL_EQUALS_PENDING(xs, priv)) {
925                                 priv->transient = 0;
926                         } else if (!priv->setup_done) {
927                                 resubmit = 0;
928                         } else if (--priv->transient == 0) {
929                                 if (xs->rx_bytes_avail == 0) {
930                                         priv->transient = 4;
931                                         priv->setup_done = 0;
932                                         resubmit = 0;
933                                         dbg("%s(): scheduling setup_line()",
934                                             __FUNCTION__);
935                                         schedule_delayed_work(&priv->delayed_setup_work, 0);
936                                 }
937                         }
938                 }
939 
940                 if (!priv->transient) {
941                         if (xs->pin_state != priv->status.pin_state)
942                                 wake_up_interruptible(&priv->intr_wait);
943                         memcpy(&priv->status, xs, OTI6858_CTRL_PKT_SIZE);
944                 }
945 
946                 if (!priv->transient && xs->rx_bytes_avail != 0) {
947                         can_recv = xs->rx_bytes_avail;
948                         priv->flags.read_urb_in_use = 1;
949                 }
950 
951                 transient = priv->transient;
952                 spin_unlock_irqrestore(&priv->lock, flags);
953         }
954 
955         if (can_recv) {
956                 int result;
957 
958                 port->read_urb->dev = port->serial->dev;
959                 result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
960                 if (result != 0) {
961                         priv->flags.read_urb_in_use = 0;
962                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
963                                         " error %d\n", __FUNCTION__, result);
964                 } else {
965                         resubmit = 0;
966                 }
967         } else if (!transient) {
968                 unsigned long flags;
969 
970                 spin_lock_irqsave(&priv->lock, flags);
971                 if (priv->flags.write_urb_in_use == 0
972                                 && oti6858_buf_data_avail(priv->buf) != 0) {
973                         schedule_delayed_work(&priv->delayed_write_work,0);
974                         resubmit = 0;
975                 }
976                 spin_unlock_irqrestore(&priv->lock, flags);
977         }
978 
979         if (resubmit) {
980                 int result;
981 
982 //              dbg("%s(): submitting interrupt urb", __FUNCTION__);
983                 urb->dev = port->serial->dev;
984                 result = usb_submit_urb(urb, GFP_ATOMIC);
985                 if (result != 0) {
986                         dev_err(&urb->dev->dev,
987                                         "%s(): usb_submit_urb() failed with"
988                                         " error %d\n", __FUNCTION__, result);
989                 }
990         }
991 }
992 
993 static void oti6858_read_bulk_callback(struct urb *urb)
994 {
995         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
996         struct oti6858_private *priv = usb_get_serial_port_data(port);
997         struct tty_struct *tty;
998         unsigned char *data = urb->transfer_buffer;
999         unsigned long flags;
1000         int status = urb->status;
1001         int result;
1002 
1003         dbg("%s(port = %d, status = %d)",
1004                                 __FUNCTION__, port->number, status);
1005 
1006         spin_lock_irqsave(&priv->lock, flags);
1007         priv->flags.read_urb_in_use = 0;
1008         spin_unlock_irqrestore(&priv->lock, flags);
1009 
1010         if (status != 0) {
1011                 if (!port->open_count) {
1012                         dbg("%s(): port is closed, exiting", __FUNCTION__);
1013                         return;
1014                 }
1015                 /*
1016                 if (status == -EPROTO) {
1017                         // PL2303 mysteriously fails with -EPROTO reschedule the read
1018                         dbg("%s - caught -EPROTO, resubmitting the urb", __FUNCTION__);
1019                         result = usb_submit_urb(urb, GFP_ATOMIC);
1020                         if (result)
1021                                 dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
1022                         return;
1023                 }
1024                 */
1025                 dbg("%s(): unable to handle the error, exiting", __FUNCTION__);
1026                 return;
1027         }
1028 
1029         tty = port->tty;
1030         if (tty != NULL && urb->actual_length > 0) {
1031                 tty_insert_flip_string(tty, data, urb->actual_length);
1032                 tty_flip_buffer_push(tty);
1033         }
1034 
1035         // schedule the interrupt urb if we are still open */
1036         if (port->open_count != 0) {
1037                 port->interrupt_in_urb->dev = port->serial->dev;
1038                 result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1039                 if (result != 0) {
1040                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1041                                         " error %d\n", __FUNCTION__, result);
1042                 }
1043         }
1044 }
1045 
1046 static void oti6858_write_bulk_callback(struct urb *urb)
1047 {
1048         struct usb_serial_port *port = (struct usb_serial_port *) urb->context;
1049         struct oti6858_private *priv = usb_get_serial_port_data(port);
1050         int status = urb->status;
1051         int result;
1052 
1053         dbg("%s(port = %d, status = %d)",
1054                                 __FUNCTION__, port->number, status);
1055 
1056         switch (status) {
1057         case 0:
1058                 /* success */
1059                 break;
1060         case -ECONNRESET:
1061         case -ENOENT:
1062         case -ESHUTDOWN:
1063                 /* this urb is terminated, clean up */
1064                 dbg("%s(): urb shutting down with status: %d",
1065                                         __FUNCTION__, status);
1066                 priv->flags.write_urb_in_use = 0;
1067                 return;
1068         default:
1069                 /* error in the urb, so we have to resubmit it */
1070                 dbg("%s(): nonzero write bulk status received: %d",
1071                                         __FUNCTION__, status);
1072                 dbg("%s(): overflow in write", __FUNCTION__);
1073 
1074                 port->write_urb->transfer_buffer_length = 1;
1075                 port->write_urb->dev = port->serial->dev;
1076                 result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
1077                 if (result) {
1078                         dev_err(&port->dev, "%s(): usb_submit_urb() failed,"
1079                                         " error %d\n", __FUNCTION__, result);
1080                 } else {
1081                         return;
1082                 }
1083         }
1084 
1085         priv->flags.write_urb_in_use = 0;
1086 
1087         // schedule the interrupt urb if we are still open */
1088         port->interrupt_in_urb->dev = port->serial->dev;
1089         dbg("%s(): submitting interrupt urb", __FUNCTION__);
1090         result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
1091         if (result != 0) {
1092                 dev_err(&port->dev, "%s(): failed submitting int urb,"
1093                                         " error %d\n", __FUNCTION__, result);
1094         }
1095 }
1096 
1097 
1098 /*
1099  * oti6858_buf_alloc
1100  *
1101  * Allocate a circular buffer and all associated memory.
1102  */
1103 static struct oti6858_buf *oti6858_buf_alloc(unsigned int size)
1104 {
1105         struct oti6858_buf *pb;
1106 
1107         if (size == 0)
1108                 return NULL;
1109 
1110         pb = kmalloc(sizeof(struct oti6858_buf), GFP_KERNEL);
1111         if (pb == NULL)
1112                 return NULL;
1113 
1114         pb->buf_buf = kmalloc(size, GFP_KERNEL);
1115         if (pb->buf_buf == NULL) {
1116                 kfree(pb);
1117                 return NULL;
1118         }
1119 
1120         pb->buf_size = size;
1121         pb->buf_get = pb->buf_put = pb->buf_buf;
1122 
1123         return pb;
1124 }
1125 
1126 /*
1127  * oti6858_buf_free
1128  *
1129  * Free the buffer and all associated memory.
1130  */
1131 static void oti6858_buf_free(struct oti6858_buf *pb)
1132 {
1133         if (pb) {
1134                 kfree(pb->buf_buf);
1135                 kfree(pb);
1136         }
1137 }
1138 
1139 /*
1140  * oti6858_buf_clear
1141  *
1142  * Clear out all data in the circular buffer.
1143  */
1144 static void oti6858_buf_clear(struct oti6858_buf *pb)
1145 {
1146         if (pb != NULL) {
1147                 /* equivalent to a get of all data available */
1148                 pb->buf_get = pb->buf_put;
1149         }
1150 }
1151 
1152 /*
1153  * oti6858_buf_data_avail
1154  *
1155  * Return the number of bytes of data available in the circular
1156  * buffer.
1157  */
1158 static unsigned int oti6858_buf_data_avail(struct oti6858_buf *pb)
1159 {
1160         if (pb == NULL)
1161                 return 0;
1162         return ((pb->buf_size + pb->buf_put - pb->buf_get) % pb->buf_size);
1163 }
1164 
1165 /*
1166  * oti6858_buf_space_avail
1167  *
1168  * Return the number of bytes of space available in the circular
1169  * buffer.
1170  */
1171 static unsigned int oti6858_buf_space_avail(struct oti6858_buf *pb)
1172 {
1173         if (pb == NULL)
1174                 return 0;
1175         return ((pb->buf_size + pb->buf_get - pb->buf_put - 1) % pb->buf_size);
1176 }
1177 
1178 /*
1179  * oti6858_buf_put
1180  *
1181  * Copy data data from a user buffer and put it into the circular buffer.
1182  * Restrict to the amount of space available.
1183  *
1184  * Return the number of bytes copied.
1185  */
1186 static unsigned int oti6858_buf_put(struct oti6858_buf *pb, const char *buf,
1187                                         unsigned int count)
1188 {
1189         unsigned int len;
1190 
1191         if (pb == NULL)
1192                 return 0;
1193 
1194         len  = oti6858_buf_space_avail(pb);
1195         if (count > len)
1196                 count = len;
1197 
1198         if (count == 0)
1199                 return 0;
1200 
1201         len = pb->buf_buf + pb->buf_size - pb->buf_put;
1202         if (count > len) {
1203                 memcpy(pb->buf_put, buf, len);
1204                 memcpy(pb->buf_buf, buf+len, count - len);
1205                 pb->buf_put = pb->buf_buf + count - len;
1206         } else {
1207                 memcpy(pb->buf_put, buf, count);
1208                 if (count < len)
1209                         pb->buf_put += count;
1210                 else /* count == len */
1211                         pb->buf_put = pb->buf_buf;
1212         }
1213 
1214         return count;
1215 }
1216 
1217 /*
1218  * oti6858_buf_get
1219  *
1220  * Get data from the circular buffer and copy to the given buffer.
1221  * Restrict to the amount of data available.
1222  *
1223  * Return the number of bytes copied.
1224  */
1225 static unsigned int oti6858_buf_get(struct oti6858_buf *pb, char *buf,
1226                                         unsigned int count)
1227 {
1228         unsigned int len;
1229 
1230         if (pb == NULL)
1231                 return 0;
1232 
1233         len = oti6858_buf_data_avail(pb);
1234         if (count > len)
1235                 count = len;
1236 
1237         if (count == 0)
1238                 return 0;
1239 
1240         len = pb->buf_buf + pb->buf_size - pb->buf_get;
1241         if (count > len) {
1242                 memcpy(buf, pb->buf_get, len);
1243                 memcpy(buf+len, pb->buf_buf, count - len);
1244                 pb->buf_get = pb->buf_buf + count - len;
1245         } else {
1246                 memcpy(buf, pb->buf_get, count);
1247                 if (count < len)
1248                         pb->buf_get += count;
1249                 else /* count == len */
1250                         pb->buf_get = pb->buf_buf;
1251         }
1252 
1253         return count;
1254 }
1255 
1256 /* module description and (de)initialization */
1257 
1258 static int __init oti6858_init(void)
1259 {
1260         int retval;
1261 
1262         if ((retval = usb_serial_register(&oti6858_device)) == 0) {
1263                 if ((retval = usb_register(&oti6858_driver)) != 0)
1264                         usb_serial_deregister(&oti6858_device);
1265                 else
1266                         return 0;
1267         }
1268 
1269         return retval;
1270 }
1271 
1272 static void __exit oti6858_exit(void)
1273 {
1274         usb_deregister(&oti6858_driver);
1275         usb_serial_deregister(&oti6858_device);
1276 }
1277 
1278 module_init(oti6858_init);
1279 module_exit(oti6858_exit);
1280 
1281 MODULE_DESCRIPTION(OTI6858_DESCRIPTION);
1282 MODULE_AUTHOR(OTI6858_AUTHOR);
1283 MODULE_VERSION(OTI6858_VERSION);
1284 MODULE_LICENSE("GPL");
1285 
1286 module_param(debug, bool, S_IRUGO | S_IWUSR);
1287 MODULE_PARM_DESC(debug, "enable debug output");
1288 
1289 
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