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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * LEGO USB Tower driver
4 *
5 * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
6 * 2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
7 *
8 * derived from USB Skeleton driver - 0.5
9 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
10 *
11 * History:
12 *
13 * 2001-10-13 - 0.1 js
14 * - first version
15 * 2001-11-03 - 0.2 js
16 * - simplified buffering, one-shot URBs for writing
17 * 2001-11-10 - 0.3 js
18 * - removed IOCTL (setting power/mode is more complicated, postponed)
19 * 2001-11-28 - 0.4 js
20 * - added vendor commands for mode of operation and power level in open
21 * 2001-12-04 - 0.5 js
22 * - set IR mode by default (by oversight 0.4 set VLL mode)
23 * 2002-01-11 - 0.5? pcchan
24 * - make read buffer reusable and work around bytes_to_write issue between
25 * uhci and legusbtower
26 * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
27 * - imported into lejos project
28 * - changed wake_up to wake_up_interruptible
29 * - changed to use lego0 rather than tower0
30 * - changed dbg() to use __func__ rather than deprecated __func__
31 * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
32 * - changed read and write to write everything or
33 * timeout (from a patch by Chris Riesen and Brett Thaeler driver)
34 * - added ioctl functionality to set timeouts
35 * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
36 * - initial import into LegoUSB project
37 * - merge of existing LegoUSB.c driver
38 * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
39 * - port to 2.6 style driver
40 * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
41 * - fix locking
42 * - unlink read URBs which are no longer needed
43 * - allow increased buffer size, eliminates need for timeout on write
44 * - have read URB running continuously
45 * - added poll
46 * - forbid seeking
47 * - added nonblocking I/O
48 * - changed back __func__ to __func__
49 * - read and log tower firmware version
50 * - reset tower on probe, avoids failure of first write
51 * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
52 * - timeout read now only after inactivity, shorten default accordingly
53 * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
54 * - log major, minor instead of possibly confusing device filename
55 * - whitespace cleanup
56 * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
57 * - normalize whitespace in debug messages
58 * - take care about endianness in control message responses
59 * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
60 * - make default intervals longer to accommodate current EHCI driver
61 * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
62 * - replaced atomic_t by memory barriers
63 * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
64 * - wait for completion of write urb in release (needed for remotecontrol)
65 * - corrected poll for write direction (missing negation)
66 * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
67 * - make device locking interruptible
68 * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
69 * - check for valid udev on resubmitting and unlinking urbs
70 * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
71 * - move reset into open to clean out spurious data
72 */
73
74#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
75
76#include <linux/kernel.h>
77#include <linux/errno.h>
78#include <linux/slab.h>
79#include <linux/module.h>
80#include <linux/completion.h>
81#include <linux/mutex.h>
82#include <linux/uaccess.h>
83#include <linux/usb.h>
84#include <linux/poll.h>
85
86
87#define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
88#define DRIVER_DESC "LEGO USB Tower Driver"
89
90
91/* The defaults are chosen to work with the latest versions of leJOS and NQC.
92 */
93
94/* Some legacy software likes to receive packets in one piece.
95 * In this case read_buffer_size should exceed the maximal packet length
96 * (417 for datalog uploads), and packet_timeout should be set.
97 */
98static int read_buffer_size = 480;
99module_param(read_buffer_size, int, 0);
100MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
101
102/* Some legacy software likes to send packets in one piece.
103 * In this case write_buffer_size should exceed the maximal packet length
104 * (417 for firmware and program downloads).
105 * A problem with long writes is that the following read may time out
106 * if the software is not prepared to wait long enough.
107 */
108static int write_buffer_size = 480;
109module_param(write_buffer_size, int, 0);
110MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
111
112/* Some legacy software expects reads to contain whole LASM packets.
113 * To achieve this, characters which arrive before a packet timeout
114 * occurs will be returned in a single read operation.
115 * A problem with long reads is that the software may time out
116 * if it is not prepared to wait long enough.
117 * The packet timeout should be greater than the time between the
118 * reception of subsequent characters, which should arrive about
119 * every 5ms for the standard 2400 baud.
120 * Set it to 0 to disable.
121 */
122static int packet_timeout = 50;
123module_param(packet_timeout, int, 0);
124MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
125
126/* Some legacy software expects blocking reads to time out.
127 * Timeout occurs after the specified time of read and write inactivity.
128 * Set it to 0 to disable.
129 */
130static int read_timeout = 200;
131module_param(read_timeout, int, 0);
132MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
133
134/* As of kernel version 2.6.4 ehci-hcd uses an
135 * "only one interrupt transfer per frame" shortcut
136 * to simplify the scheduling of periodic transfers.
137 * This conflicts with our standard 1ms intervals for in and out URBs.
138 * We use default intervals of 2ms for in and 8ms for out transfers,
139 * which is fast enough for 2400 baud and allows a small additional load.
140 * Increase the interval to allow more devices that do interrupt transfers,
141 * or set to 0 to use the standard interval from the endpoint descriptors.
142 */
143static int interrupt_in_interval = 2;
144module_param(interrupt_in_interval, int, 0);
145MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
146
147static int interrupt_out_interval = 8;
148module_param(interrupt_out_interval, int, 0);
149MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
150
151/* Define these values to match your device */
152#define LEGO_USB_TOWER_VENDOR_ID 0x0694
153#define LEGO_USB_TOWER_PRODUCT_ID 0x0001
154
155/* Vendor requests */
156#define LEGO_USB_TOWER_REQUEST_RESET 0x04
157#define LEGO_USB_TOWER_REQUEST_GET_VERSION 0xFD
158
159struct tower_reset_reply {
160 __le16 size; /* little-endian */
161 __u8 err_code;
162 __u8 spare;
163} __attribute__ ((packed));
164
165struct tower_get_version_reply {
166 __le16 size; /* little-endian */
167 __u8 err_code;
168 __u8 spare;
169 __u8 major;
170 __u8 minor;
171 __le16 build_no; /* little-endian */
172} __attribute__ ((packed));
173
174
175/* table of devices that work with this driver */
176static const struct usb_device_id tower_table[] = {
177 { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
178 { } /* Terminating entry */
179};
180
181MODULE_DEVICE_TABLE (usb, tower_table);
182
183#define LEGO_USB_TOWER_MINOR_BASE 160
184
185
186/* Structure to hold all of our device specific stuff */
187struct lego_usb_tower {
188 struct mutex lock; /* locks this structure */
189 struct usb_device* udev; /* save off the usb device pointer */
190 unsigned char minor; /* the starting minor number for this device */
191
192 int open_count; /* number of times this port has been opened */
193 unsigned long disconnected:1;
194
195 char* read_buffer;
196 size_t read_buffer_length; /* this much came in */
197 size_t read_packet_length; /* this much will be returned on read */
198 spinlock_t read_buffer_lock;
199 int packet_timeout_jiffies;
200 unsigned long read_last_arrival;
201
202 wait_queue_head_t read_wait;
203 wait_queue_head_t write_wait;
204
205 char* interrupt_in_buffer;
206 struct usb_endpoint_descriptor* interrupt_in_endpoint;
207 struct urb* interrupt_in_urb;
208 int interrupt_in_interval;
209 int interrupt_in_running;
210 int interrupt_in_done;
211
212 char* interrupt_out_buffer;
213 struct usb_endpoint_descriptor* interrupt_out_endpoint;
214 struct urb* interrupt_out_urb;
215 int interrupt_out_interval;
216 int interrupt_out_busy;
217
218};
219
220
221/* local function prototypes */
222static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
223static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
224static inline void tower_delete (struct lego_usb_tower *dev);
225static int tower_open (struct inode *inode, struct file *file);
226static int tower_release (struct inode *inode, struct file *file);
227static __poll_t tower_poll (struct file *file, poll_table *wait);
228static loff_t tower_llseek (struct file *file, loff_t off, int whence);
229
230static void tower_abort_transfers (struct lego_usb_tower *dev);
231static void tower_check_for_read_packet (struct lego_usb_tower *dev);
232static void tower_interrupt_in_callback (struct urb *urb);
233static void tower_interrupt_out_callback (struct urb *urb);
234
235static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
236static void tower_disconnect (struct usb_interface *interface);
237
238
239/* file operations needed when we register this driver */
240static const struct file_operations tower_fops = {
241 .owner = THIS_MODULE,
242 .read = tower_read,
243 .write = tower_write,
244 .open = tower_open,
245 .release = tower_release,
246 .poll = tower_poll,
247 .llseek = tower_llseek,
248};
249
250static char *legousbtower_devnode(struct device *dev, umode_t *mode)
251{
252 return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
253}
254
255/*
256 * usb class driver info in order to get a minor number from the usb core,
257 * and to have the device registered with the driver core
258 */
259static struct usb_class_driver tower_class = {
260 .name = "legousbtower%d",
261 .devnode = legousbtower_devnode,
262 .fops = &tower_fops,
263 .minor_base = LEGO_USB_TOWER_MINOR_BASE,
264};
265
266
267/* usb specific object needed to register this driver with the usb subsystem */
268static struct usb_driver tower_driver = {
269 .name = "legousbtower",
270 .probe = tower_probe,
271 .disconnect = tower_disconnect,
272 .id_table = tower_table,
273};
274
275
276/**
277 * lego_usb_tower_debug_data
278 */
279static inline void lego_usb_tower_debug_data(struct device *dev,
280 const char *function, int size,
281 const unsigned char *data)
282{
283 dev_dbg(dev, "%s - length = %d, data = %*ph\n",
284 function, size, size, data);
285}
286
287
288/**
289 * tower_delete
290 */
291static inline void tower_delete (struct lego_usb_tower *dev)
292{
293 /* free data structures */
294 usb_free_urb(dev->interrupt_in_urb);
295 usb_free_urb(dev->interrupt_out_urb);
296 kfree (dev->read_buffer);
297 kfree (dev->interrupt_in_buffer);
298 kfree (dev->interrupt_out_buffer);
299 usb_put_dev(dev->udev);
300 kfree (dev);
301}
302
303
304/**
305 * tower_open
306 */
307static int tower_open (struct inode *inode, struct file *file)
308{
309 struct lego_usb_tower *dev = NULL;
310 int subminor;
311 int retval = 0;
312 struct usb_interface *interface;
313 struct tower_reset_reply *reset_reply;
314 int result;
315
316 reset_reply = kmalloc(sizeof(*reset_reply), GFP_KERNEL);
317
318 if (!reset_reply) {
319 retval = -ENOMEM;
320 goto exit;
321 }
322
323 nonseekable_open(inode, file);
324 subminor = iminor(inode);
325
326 interface = usb_find_interface (&tower_driver, subminor);
327
328 if (!interface) {
329 pr_err("error, can't find device for minor %d\n", subminor);
330 retval = -ENODEV;
331 goto exit;
332 }
333
334 dev = usb_get_intfdata(interface);
335 if (!dev) {
336 retval = -ENODEV;
337 goto exit;
338 }
339
340 /* lock this device */
341 if (mutex_lock_interruptible(&dev->lock)) {
342 retval = -ERESTARTSYS;
343 goto exit;
344 }
345
346
347 /* allow opening only once */
348 if (dev->open_count) {
349 retval = -EBUSY;
350 goto unlock_exit;
351 }
352
353 /* reset the tower */
354 result = usb_control_msg (dev->udev,
355 usb_rcvctrlpipe(dev->udev, 0),
356 LEGO_USB_TOWER_REQUEST_RESET,
357 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
358 0,
359 0,
360 reset_reply,
361 sizeof(*reset_reply),
362 1000);
363 if (result < 0) {
364 dev_err(&dev->udev->dev,
365 "LEGO USB Tower reset control request failed\n");
366 retval = result;
367 goto unlock_exit;
368 }
369
370 /* initialize in direction */
371 dev->read_buffer_length = 0;
372 dev->read_packet_length = 0;
373 usb_fill_int_urb (dev->interrupt_in_urb,
374 dev->udev,
375 usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
376 dev->interrupt_in_buffer,
377 usb_endpoint_maxp(dev->interrupt_in_endpoint),
378 tower_interrupt_in_callback,
379 dev,
380 dev->interrupt_in_interval);
381
382 dev->interrupt_in_running = 1;
383 dev->interrupt_in_done = 0;
384 mb();
385
386 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
387 if (retval) {
388 dev_err(&dev->udev->dev,
389 "Couldn't submit interrupt_in_urb %d\n", retval);
390 dev->interrupt_in_running = 0;
391 goto unlock_exit;
392 }
393
394 /* save device in the file's private structure */
395 file->private_data = dev;
396
397 dev->open_count = 1;
398
399unlock_exit:
400 mutex_unlock(&dev->lock);
401
402exit:
403 kfree(reset_reply);
404 return retval;
405}
406
407/**
408 * tower_release
409 */
410static int tower_release (struct inode *inode, struct file *file)
411{
412 struct lego_usb_tower *dev;
413 int retval = 0;
414
415 dev = file->private_data;
416
417 if (dev == NULL) {
418 retval = -ENODEV;
419 goto exit;
420 }
421
422 mutex_lock(&dev->lock);
423
424 if (dev->open_count != 1) {
425 dev_dbg(&dev->udev->dev, "%s: device not opened exactly once\n",
426 __func__);
427 retval = -ENODEV;
428 goto unlock_exit;
429 }
430
431 if (dev->disconnected) {
432 /* the device was unplugged before the file was released */
433
434 /* unlock here as tower_delete frees dev */
435 mutex_unlock(&dev->lock);
436 tower_delete (dev);
437 goto exit;
438 }
439
440 /* wait until write transfer is finished */
441 if (dev->interrupt_out_busy) {
442 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
443 }
444 tower_abort_transfers (dev);
445 dev->open_count = 0;
446
447unlock_exit:
448 mutex_unlock(&dev->lock);
449exit:
450 return retval;
451}
452
453
454/**
455 * tower_abort_transfers
456 * aborts transfers and frees associated data structures
457 */
458static void tower_abort_transfers (struct lego_usb_tower *dev)
459{
460 if (dev == NULL)
461 return;
462
463 /* shutdown transfer */
464 if (dev->interrupt_in_running) {
465 dev->interrupt_in_running = 0;
466 mb();
467 usb_kill_urb(dev->interrupt_in_urb);
468 }
469 if (dev->interrupt_out_busy)
470 usb_kill_urb(dev->interrupt_out_urb);
471}
472
473
474/**
475 * tower_check_for_read_packet
476 *
477 * To get correct semantics for signals and non-blocking I/O
478 * with packetizing we pretend not to see any data in the read buffer
479 * until it has been there unchanged for at least
480 * dev->packet_timeout_jiffies, or until the buffer is full.
481 */
482static void tower_check_for_read_packet (struct lego_usb_tower *dev)
483{
484 spin_lock_irq (&dev->read_buffer_lock);
485 if (!packet_timeout
486 || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
487 || dev->read_buffer_length == read_buffer_size) {
488 dev->read_packet_length = dev->read_buffer_length;
489 }
490 dev->interrupt_in_done = 0;
491 spin_unlock_irq (&dev->read_buffer_lock);
492}
493
494
495/**
496 * tower_poll
497 */
498static __poll_t tower_poll (struct file *file, poll_table *wait)
499{
500 struct lego_usb_tower *dev;
501 __poll_t mask = 0;
502
503 dev = file->private_data;
504
505 if (dev->disconnected)
506 return EPOLLERR | EPOLLHUP;
507
508 poll_wait(file, &dev->read_wait, wait);
509 poll_wait(file, &dev->write_wait, wait);
510
511 tower_check_for_read_packet(dev);
512 if (dev->read_packet_length > 0) {
513 mask |= EPOLLIN | EPOLLRDNORM;
514 }
515 if (!dev->interrupt_out_busy) {
516 mask |= EPOLLOUT | EPOLLWRNORM;
517 }
518
519 return mask;
520}
521
522
523/**
524 * tower_llseek
525 */
526static loff_t tower_llseek (struct file *file, loff_t off, int whence)
527{
528 return -ESPIPE; /* unseekable */
529}
530
531
532/**
533 * tower_read
534 */
535static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
536{
537 struct lego_usb_tower *dev;
538 size_t bytes_to_read;
539 int i;
540 int retval = 0;
541 unsigned long timeout = 0;
542
543 dev = file->private_data;
544
545 /* lock this object */
546 if (mutex_lock_interruptible(&dev->lock)) {
547 retval = -ERESTARTSYS;
548 goto exit;
549 }
550
551 /* verify that the device wasn't unplugged */
552 if (dev->disconnected) {
553 retval = -ENODEV;
554 pr_err("No device or device unplugged %d\n", retval);
555 goto unlock_exit;
556 }
557
558 /* verify that we actually have some data to read */
559 if (count == 0) {
560 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
561 goto unlock_exit;
562 }
563
564 if (read_timeout) {
565 timeout = jiffies + msecs_to_jiffies(read_timeout);
566 }
567
568 /* wait for data */
569 tower_check_for_read_packet (dev);
570 while (dev->read_packet_length == 0) {
571 if (file->f_flags & O_NONBLOCK) {
572 retval = -EAGAIN;
573 goto unlock_exit;
574 }
575 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
576 if (retval < 0) {
577 goto unlock_exit;
578 }
579
580 /* reset read timeout during read or write activity */
581 if (read_timeout
582 && (dev->read_buffer_length || dev->interrupt_out_busy)) {
583 timeout = jiffies + msecs_to_jiffies(read_timeout);
584 }
585 /* check for read timeout */
586 if (read_timeout && time_after (jiffies, timeout)) {
587 retval = -ETIMEDOUT;
588 goto unlock_exit;
589 }
590 tower_check_for_read_packet (dev);
591 }
592
593 /* copy the data from read_buffer into userspace */
594 bytes_to_read = min(count, dev->read_packet_length);
595
596 if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
597 retval = -EFAULT;
598 goto unlock_exit;
599 }
600
601 spin_lock_irq (&dev->read_buffer_lock);
602 dev->read_buffer_length -= bytes_to_read;
603 dev->read_packet_length -= bytes_to_read;
604 for (i=0; i<dev->read_buffer_length; i++) {
605 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
606 }
607 spin_unlock_irq (&dev->read_buffer_lock);
608
609 retval = bytes_to_read;
610
611unlock_exit:
612 /* unlock the device */
613 mutex_unlock(&dev->lock);
614
615exit:
616 return retval;
617}
618
619
620/**
621 * tower_write
622 */
623static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
624{
625 struct lego_usb_tower *dev;
626 size_t bytes_to_write;
627 int retval = 0;
628
629 dev = file->private_data;
630
631 /* lock this object */
632 if (mutex_lock_interruptible(&dev->lock)) {
633 retval = -ERESTARTSYS;
634 goto exit;
635 }
636
637 /* verify that the device wasn't unplugged */
638 if (dev->disconnected) {
639 retval = -ENODEV;
640 pr_err("No device or device unplugged %d\n", retval);
641 goto unlock_exit;
642 }
643
644 /* verify that we actually have some data to write */
645 if (count == 0) {
646 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
647 goto unlock_exit;
648 }
649
650 /* wait until previous transfer is finished */
651 while (dev->interrupt_out_busy) {
652 if (file->f_flags & O_NONBLOCK) {
653 retval = -EAGAIN;
654 goto unlock_exit;
655 }
656 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
657 if (retval) {
658 goto unlock_exit;
659 }
660 }
661
662 /* write the data into interrupt_out_buffer from userspace */
663 bytes_to_write = min_t(int, count, write_buffer_size);
664 dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
665 __func__, count, bytes_to_write);
666
667 if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
668 retval = -EFAULT;
669 goto unlock_exit;
670 }
671
672 /* send off the urb */
673 usb_fill_int_urb(dev->interrupt_out_urb,
674 dev->udev,
675 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
676 dev->interrupt_out_buffer,
677 bytes_to_write,
678 tower_interrupt_out_callback,
679 dev,
680 dev->interrupt_out_interval);
681
682 dev->interrupt_out_busy = 1;
683 wmb();
684
685 retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
686 if (retval) {
687 dev->interrupt_out_busy = 0;
688 dev_err(&dev->udev->dev,
689 "Couldn't submit interrupt_out_urb %d\n", retval);
690 goto unlock_exit;
691 }
692 retval = bytes_to_write;
693
694unlock_exit:
695 /* unlock the device */
696 mutex_unlock(&dev->lock);
697
698exit:
699 return retval;
700}
701
702
703/**
704 * tower_interrupt_in_callback
705 */
706static void tower_interrupt_in_callback (struct urb *urb)
707{
708 struct lego_usb_tower *dev = urb->context;
709 int status = urb->status;
710 int retval;
711 unsigned long flags;
712
713 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
714 urb->actual_length, urb->transfer_buffer);
715
716 if (status) {
717 if (status == -ENOENT ||
718 status == -ECONNRESET ||
719 status == -ESHUTDOWN) {
720 goto exit;
721 } else {
722 dev_dbg(&dev->udev->dev,
723 "%s: nonzero status received: %d\n", __func__,
724 status);
725 goto resubmit; /* maybe we can recover */
726 }
727 }
728
729 if (urb->actual_length > 0) {
730 spin_lock_irqsave(&dev->read_buffer_lock, flags);
731 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
732 memcpy (dev->read_buffer + dev->read_buffer_length,
733 dev->interrupt_in_buffer,
734 urb->actual_length);
735 dev->read_buffer_length += urb->actual_length;
736 dev->read_last_arrival = jiffies;
737 dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
738 __func__, urb->actual_length);
739 } else {
740 pr_warn("read_buffer overflow, %d bytes dropped\n",
741 urb->actual_length);
742 }
743 spin_unlock_irqrestore(&dev->read_buffer_lock, flags);
744 }
745
746resubmit:
747 /* resubmit if we're still running */
748 if (dev->interrupt_in_running) {
749 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
750 if (retval)
751 dev_err(&dev->udev->dev,
752 "%s: usb_submit_urb failed (%d)\n",
753 __func__, retval);
754 }
755
756exit:
757 dev->interrupt_in_done = 1;
758 wake_up_interruptible (&dev->read_wait);
759}
760
761
762/**
763 * tower_interrupt_out_callback
764 */
765static void tower_interrupt_out_callback (struct urb *urb)
766{
767 struct lego_usb_tower *dev = urb->context;
768 int status = urb->status;
769
770 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
771 urb->actual_length, urb->transfer_buffer);
772
773 /* sync/async unlink faults aren't errors */
774 if (status && !(status == -ENOENT ||
775 status == -ECONNRESET ||
776 status == -ESHUTDOWN)) {
777 dev_dbg(&dev->udev->dev,
778 "%s: nonzero write bulk status received: %d\n", __func__,
779 status);
780 }
781
782 dev->interrupt_out_busy = 0;
783 wake_up_interruptible(&dev->write_wait);
784}
785
786
787/**
788 * tower_probe
789 *
790 * Called by the usb core when a new device is connected that it thinks
791 * this driver might be interested in.
792 */
793static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
794{
795 struct device *idev = &interface->dev;
796 struct usb_device *udev = interface_to_usbdev(interface);
797 struct lego_usb_tower *dev = NULL;
798 struct tower_get_version_reply *get_version_reply = NULL;
799 int retval = -ENOMEM;
800 int result;
801
802 /* allocate memory for our device state and initialize it */
803
804 dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
805
806 if (!dev)
807 goto exit;
808
809 mutex_init(&dev->lock);
810
811 dev->udev = usb_get_dev(udev);
812 dev->open_count = 0;
813 dev->disconnected = 0;
814
815 dev->read_buffer = NULL;
816 dev->read_buffer_length = 0;
817 dev->read_packet_length = 0;
818 spin_lock_init (&dev->read_buffer_lock);
819 dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
820 dev->read_last_arrival = jiffies;
821
822 init_waitqueue_head (&dev->read_wait);
823 init_waitqueue_head (&dev->write_wait);
824
825 dev->interrupt_in_buffer = NULL;
826 dev->interrupt_in_endpoint = NULL;
827 dev->interrupt_in_urb = NULL;
828 dev->interrupt_in_running = 0;
829 dev->interrupt_in_done = 0;
830
831 dev->interrupt_out_buffer = NULL;
832 dev->interrupt_out_endpoint = NULL;
833 dev->interrupt_out_urb = NULL;
834 dev->interrupt_out_busy = 0;
835
836 result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
837 NULL, NULL,
838 &dev->interrupt_in_endpoint,
839 &dev->interrupt_out_endpoint);
840 if (result) {
841 dev_err(idev, "interrupt endpoints not found\n");
842 retval = result;
843 goto error;
844 }
845
846 dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
847 if (!dev->read_buffer)
848 goto error;
849 dev->interrupt_in_buffer = kmalloc (usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
850 if (!dev->interrupt_in_buffer)
851 goto error;
852 dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
853 if (!dev->interrupt_in_urb)
854 goto error;
855 dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
856 if (!dev->interrupt_out_buffer)
857 goto error;
858 dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
859 if (!dev->interrupt_out_urb)
860 goto error;
861 dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
862 dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
863
864 get_version_reply = kmalloc(sizeof(*get_version_reply), GFP_KERNEL);
865
866 if (!get_version_reply) {
867 retval = -ENOMEM;
868 goto error;
869 }
870
871 /* get the firmware version and log it */
872 result = usb_control_msg (udev,
873 usb_rcvctrlpipe(udev, 0),
874 LEGO_USB_TOWER_REQUEST_GET_VERSION,
875 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
876 0,
877 0,
878 get_version_reply,
879 sizeof(*get_version_reply),
880 1000);
881 if (result != sizeof(*get_version_reply)) {
882 if (result >= 0)
883 result = -EIO;
884 dev_err(idev, "get version request failed: %d\n", result);
885 retval = result;
886 goto error;
887 }
888 dev_info(&interface->dev,
889 "LEGO USB Tower firmware version is %d.%d build %d\n",
890 get_version_reply->major,
891 get_version_reply->minor,
892 le16_to_cpu(get_version_reply->build_no));
893
894 /* we can register the device now, as it is ready */
895 usb_set_intfdata (interface, dev);
896
897 retval = usb_register_dev (interface, &tower_class);
898
899 if (retval) {
900 /* something prevented us from registering this driver */
901 dev_err(idev, "Not able to get a minor for this device.\n");
902 goto error;
903 }
904 dev->minor = interface->minor;
905
906 /* let the user know what node this device is now attached to */
907 dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
908 "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
909 USB_MAJOR, dev->minor);
910
911exit:
912 kfree(get_version_reply);
913 return retval;
914
915error:
916 kfree(get_version_reply);
917 tower_delete(dev);
918 return retval;
919}
920
921
922/**
923 * tower_disconnect
924 *
925 * Called by the usb core when the device is removed from the system.
926 */
927static void tower_disconnect (struct usb_interface *interface)
928{
929 struct lego_usb_tower *dev;
930 int minor;
931
932 dev = usb_get_intfdata (interface);
933
934 minor = dev->minor;
935
936 /* give back our minor and prevent further open() */
937 usb_deregister_dev (interface, &tower_class);
938
939 /* stop I/O */
940 usb_poison_urb(dev->interrupt_in_urb);
941 usb_poison_urb(dev->interrupt_out_urb);
942
943 mutex_lock(&dev->lock);
944
945 /* if the device is not opened, then we clean up right now */
946 if (!dev->open_count) {
947 mutex_unlock(&dev->lock);
948 tower_delete (dev);
949 } else {
950 dev->disconnected = 1;
951 /* wake up pollers */
952 wake_up_interruptible_all(&dev->read_wait);
953 wake_up_interruptible_all(&dev->write_wait);
954 mutex_unlock(&dev->lock);
955 }
956
957 dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
958 (minor - LEGO_USB_TOWER_MINOR_BASE));
959}
960
961module_usb_driver(tower_driver);
962
963MODULE_AUTHOR(DRIVER_AUTHOR);
964MODULE_DESCRIPTION(DRIVER_DESC);
965#ifdef MODULE_LICENSE
966MODULE_LICENSE("GPL");
967#endif
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * LEGO USB Tower driver
4 *
5 * Copyright (C) 2003 David Glance <davidgsf@sourceforge.net>
6 * 2001-2004 Juergen Stuber <starblue@users.sourceforge.net>
7 *
8 * derived from USB Skeleton driver - 0.5
9 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
10 *
11 * History:
12 *
13 * 2001-10-13 - 0.1 js
14 * - first version
15 * 2001-11-03 - 0.2 js
16 * - simplified buffering, one-shot URBs for writing
17 * 2001-11-10 - 0.3 js
18 * - removed IOCTL (setting power/mode is more complicated, postponed)
19 * 2001-11-28 - 0.4 js
20 * - added vendor commands for mode of operation and power level in open
21 * 2001-12-04 - 0.5 js
22 * - set IR mode by default (by oversight 0.4 set VLL mode)
23 * 2002-01-11 - 0.5? pcchan
24 * - make read buffer reusable and work around bytes_to_write issue between
25 * uhci and legusbtower
26 * 2002-09-23 - 0.52 david (david@csse.uwa.edu.au)
27 * - imported into lejos project
28 * - changed wake_up to wake_up_interruptible
29 * - changed to use lego0 rather than tower0
30 * - changed dbg() to use __func__ rather than deprecated __func__
31 * 2003-01-12 - 0.53 david (david@csse.uwa.edu.au)
32 * - changed read and write to write everything or
33 * timeout (from a patch by Chris Riesen and Brett Thaeler driver)
34 * - added ioctl functionality to set timeouts
35 * 2003-07-18 - 0.54 davidgsf (david@csse.uwa.edu.au)
36 * - initial import into LegoUSB project
37 * - merge of existing LegoUSB.c driver
38 * 2003-07-18 - 0.56 davidgsf (david@csse.uwa.edu.au)
39 * - port to 2.6 style driver
40 * 2004-02-29 - 0.6 Juergen Stuber <starblue@users.sourceforge.net>
41 * - fix locking
42 * - unlink read URBs which are no longer needed
43 * - allow increased buffer size, eliminates need for timeout on write
44 * - have read URB running continuously
45 * - added poll
46 * - forbid seeking
47 * - added nonblocking I/O
48 * - changed back __func__ to __func__
49 * - read and log tower firmware version
50 * - reset tower on probe, avoids failure of first write
51 * 2004-03-09 - 0.7 Juergen Stuber <starblue@users.sourceforge.net>
52 * - timeout read now only after inactivity, shorten default accordingly
53 * 2004-03-11 - 0.8 Juergen Stuber <starblue@users.sourceforge.net>
54 * - log major, minor instead of possibly confusing device filename
55 * - whitespace cleanup
56 * 2004-03-12 - 0.9 Juergen Stuber <starblue@users.sourceforge.net>
57 * - normalize whitespace in debug messages
58 * - take care about endianness in control message responses
59 * 2004-03-13 - 0.91 Juergen Stuber <starblue@users.sourceforge.net>
60 * - make default intervals longer to accommodate current EHCI driver
61 * 2004-03-19 - 0.92 Juergen Stuber <starblue@users.sourceforge.net>
62 * - replaced atomic_t by memory barriers
63 * 2004-04-21 - 0.93 Juergen Stuber <starblue@users.sourceforge.net>
64 * - wait for completion of write urb in release (needed for remotecontrol)
65 * - corrected poll for write direction (missing negation)
66 * 2004-04-22 - 0.94 Juergen Stuber <starblue@users.sourceforge.net>
67 * - make device locking interruptible
68 * 2004-04-30 - 0.95 Juergen Stuber <starblue@users.sourceforge.net>
69 * - check for valid udev on resubmitting and unlinking urbs
70 * 2004-08-03 - 0.96 Juergen Stuber <starblue@users.sourceforge.net>
71 * - move reset into open to clean out spurious data
72 */
73
74#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
75
76#include <linux/kernel.h>
77#include <linux/errno.h>
78#include <linux/slab.h>
79#include <linux/module.h>
80#include <linux/completion.h>
81#include <linux/mutex.h>
82#include <linux/uaccess.h>
83#include <linux/usb.h>
84#include <linux/poll.h>
85
86
87#define DRIVER_AUTHOR "Juergen Stuber <starblue@sourceforge.net>"
88#define DRIVER_DESC "LEGO USB Tower Driver"
89
90
91/* The defaults are chosen to work with the latest versions of leJOS and NQC.
92 */
93
94/* Some legacy software likes to receive packets in one piece.
95 * In this case read_buffer_size should exceed the maximal packet length
96 * (417 for datalog uploads), and packet_timeout should be set.
97 */
98static int read_buffer_size = 480;
99module_param(read_buffer_size, int, 0);
100MODULE_PARM_DESC(read_buffer_size, "Read buffer size");
101
102/* Some legacy software likes to send packets in one piece.
103 * In this case write_buffer_size should exceed the maximal packet length
104 * (417 for firmware and program downloads).
105 * A problem with long writes is that the following read may time out
106 * if the software is not prepared to wait long enough.
107 */
108static int write_buffer_size = 480;
109module_param(write_buffer_size, int, 0);
110MODULE_PARM_DESC(write_buffer_size, "Write buffer size");
111
112/* Some legacy software expects reads to contain whole LASM packets.
113 * To achieve this, characters which arrive before a packet timeout
114 * occurs will be returned in a single read operation.
115 * A problem with long reads is that the software may time out
116 * if it is not prepared to wait long enough.
117 * The packet timeout should be greater than the time between the
118 * reception of subsequent characters, which should arrive about
119 * every 5ms for the standard 2400 baud.
120 * Set it to 0 to disable.
121 */
122static int packet_timeout = 50;
123module_param(packet_timeout, int, 0);
124MODULE_PARM_DESC(packet_timeout, "Packet timeout in ms");
125
126/* Some legacy software expects blocking reads to time out.
127 * Timeout occurs after the specified time of read and write inactivity.
128 * Set it to 0 to disable.
129 */
130static int read_timeout = 200;
131module_param(read_timeout, int, 0);
132MODULE_PARM_DESC(read_timeout, "Read timeout in ms");
133
134/* As of kernel version 2.6.4 ehci-hcd uses an
135 * "only one interrupt transfer per frame" shortcut
136 * to simplify the scheduling of periodic transfers.
137 * This conflicts with our standard 1ms intervals for in and out URBs.
138 * We use default intervals of 2ms for in and 8ms for out transfers,
139 * which is fast enough for 2400 baud and allows a small additional load.
140 * Increase the interval to allow more devices that do interrupt transfers,
141 * or set to 0 to use the standard interval from the endpoint descriptors.
142 */
143static int interrupt_in_interval = 2;
144module_param(interrupt_in_interval, int, 0);
145MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms");
146
147static int interrupt_out_interval = 8;
148module_param(interrupt_out_interval, int, 0);
149MODULE_PARM_DESC(interrupt_out_interval, "Interrupt out interval in ms");
150
151/* Define these values to match your device */
152#define LEGO_USB_TOWER_VENDOR_ID 0x0694
153#define LEGO_USB_TOWER_PRODUCT_ID 0x0001
154
155/* Vendor requests */
156#define LEGO_USB_TOWER_REQUEST_RESET 0x04
157#define LEGO_USB_TOWER_REQUEST_GET_VERSION 0xFD
158
159struct tower_reset_reply {
160 __le16 size; /* little-endian */
161 __u8 err_code;
162 __u8 spare;
163} __attribute__ ((packed));
164
165struct tower_get_version_reply {
166 __le16 size; /* little-endian */
167 __u8 err_code;
168 __u8 spare;
169 __u8 major;
170 __u8 minor;
171 __le16 build_no; /* little-endian */
172} __attribute__ ((packed));
173
174
175/* table of devices that work with this driver */
176static const struct usb_device_id tower_table[] = {
177 { USB_DEVICE(LEGO_USB_TOWER_VENDOR_ID, LEGO_USB_TOWER_PRODUCT_ID) },
178 { } /* Terminating entry */
179};
180
181MODULE_DEVICE_TABLE (usb, tower_table);
182static DEFINE_MUTEX(open_disc_mutex);
183
184#define LEGO_USB_TOWER_MINOR_BASE 160
185
186
187/* Structure to hold all of our device specific stuff */
188struct lego_usb_tower {
189 struct mutex lock; /* locks this structure */
190 struct usb_device* udev; /* save off the usb device pointer */
191 unsigned char minor; /* the starting minor number for this device */
192
193 int open_count; /* number of times this port has been opened */
194
195 char* read_buffer;
196 size_t read_buffer_length; /* this much came in */
197 size_t read_packet_length; /* this much will be returned on read */
198 spinlock_t read_buffer_lock;
199 int packet_timeout_jiffies;
200 unsigned long read_last_arrival;
201
202 wait_queue_head_t read_wait;
203 wait_queue_head_t write_wait;
204
205 char* interrupt_in_buffer;
206 struct usb_endpoint_descriptor* interrupt_in_endpoint;
207 struct urb* interrupt_in_urb;
208 int interrupt_in_interval;
209 int interrupt_in_running;
210 int interrupt_in_done;
211
212 char* interrupt_out_buffer;
213 struct usb_endpoint_descriptor* interrupt_out_endpoint;
214 struct urb* interrupt_out_urb;
215 int interrupt_out_interval;
216 int interrupt_out_busy;
217
218};
219
220
221/* local function prototypes */
222static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos);
223static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
224static inline void tower_delete (struct lego_usb_tower *dev);
225static int tower_open (struct inode *inode, struct file *file);
226static int tower_release (struct inode *inode, struct file *file);
227static __poll_t tower_poll (struct file *file, poll_table *wait);
228static loff_t tower_llseek (struct file *file, loff_t off, int whence);
229
230static void tower_abort_transfers (struct lego_usb_tower *dev);
231static void tower_check_for_read_packet (struct lego_usb_tower *dev);
232static void tower_interrupt_in_callback (struct urb *urb);
233static void tower_interrupt_out_callback (struct urb *urb);
234
235static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id);
236static void tower_disconnect (struct usb_interface *interface);
237
238
239/* file operations needed when we register this driver */
240static const struct file_operations tower_fops = {
241 .owner = THIS_MODULE,
242 .read = tower_read,
243 .write = tower_write,
244 .open = tower_open,
245 .release = tower_release,
246 .poll = tower_poll,
247 .llseek = tower_llseek,
248};
249
250static char *legousbtower_devnode(struct device *dev, umode_t *mode)
251{
252 return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
253}
254
255/*
256 * usb class driver info in order to get a minor number from the usb core,
257 * and to have the device registered with the driver core
258 */
259static struct usb_class_driver tower_class = {
260 .name = "legousbtower%d",
261 .devnode = legousbtower_devnode,
262 .fops = &tower_fops,
263 .minor_base = LEGO_USB_TOWER_MINOR_BASE,
264};
265
266
267/* usb specific object needed to register this driver with the usb subsystem */
268static struct usb_driver tower_driver = {
269 .name = "legousbtower",
270 .probe = tower_probe,
271 .disconnect = tower_disconnect,
272 .id_table = tower_table,
273};
274
275
276/**
277 * lego_usb_tower_debug_data
278 */
279static inline void lego_usb_tower_debug_data(struct device *dev,
280 const char *function, int size,
281 const unsigned char *data)
282{
283 dev_dbg(dev, "%s - length = %d, data = %*ph\n",
284 function, size, size, data);
285}
286
287
288/**
289 * tower_delete
290 */
291static inline void tower_delete (struct lego_usb_tower *dev)
292{
293 tower_abort_transfers (dev);
294
295 /* free data structures */
296 usb_free_urb(dev->interrupt_in_urb);
297 usb_free_urb(dev->interrupt_out_urb);
298 kfree (dev->read_buffer);
299 kfree (dev->interrupt_in_buffer);
300 kfree (dev->interrupt_out_buffer);
301 kfree (dev);
302}
303
304
305/**
306 * tower_open
307 */
308static int tower_open (struct inode *inode, struct file *file)
309{
310 struct lego_usb_tower *dev = NULL;
311 int subminor;
312 int retval = 0;
313 struct usb_interface *interface;
314 struct tower_reset_reply *reset_reply;
315 int result;
316
317 reset_reply = kmalloc(sizeof(*reset_reply), GFP_KERNEL);
318
319 if (!reset_reply) {
320 retval = -ENOMEM;
321 goto exit;
322 }
323
324 nonseekable_open(inode, file);
325 subminor = iminor(inode);
326
327 interface = usb_find_interface (&tower_driver, subminor);
328
329 if (!interface) {
330 pr_err("error, can't find device for minor %d\n", subminor);
331 retval = -ENODEV;
332 goto exit;
333 }
334
335 mutex_lock(&open_disc_mutex);
336 dev = usb_get_intfdata(interface);
337
338 if (!dev) {
339 mutex_unlock(&open_disc_mutex);
340 retval = -ENODEV;
341 goto exit;
342 }
343
344 /* lock this device */
345 if (mutex_lock_interruptible(&dev->lock)) {
346 mutex_unlock(&open_disc_mutex);
347 retval = -ERESTARTSYS;
348 goto exit;
349 }
350
351
352 /* allow opening only once */
353 if (dev->open_count) {
354 mutex_unlock(&open_disc_mutex);
355 retval = -EBUSY;
356 goto unlock_exit;
357 }
358 dev->open_count = 1;
359 mutex_unlock(&open_disc_mutex);
360
361 /* reset the tower */
362 result = usb_control_msg (dev->udev,
363 usb_rcvctrlpipe(dev->udev, 0),
364 LEGO_USB_TOWER_REQUEST_RESET,
365 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
366 0,
367 0,
368 reset_reply,
369 sizeof(*reset_reply),
370 1000);
371 if (result < 0) {
372 dev_err(&dev->udev->dev,
373 "LEGO USB Tower reset control request failed\n");
374 retval = result;
375 goto unlock_exit;
376 }
377
378 /* initialize in direction */
379 dev->read_buffer_length = 0;
380 dev->read_packet_length = 0;
381 usb_fill_int_urb (dev->interrupt_in_urb,
382 dev->udev,
383 usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
384 dev->interrupt_in_buffer,
385 usb_endpoint_maxp(dev->interrupt_in_endpoint),
386 tower_interrupt_in_callback,
387 dev,
388 dev->interrupt_in_interval);
389
390 dev->interrupt_in_running = 1;
391 dev->interrupt_in_done = 0;
392 mb();
393
394 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_KERNEL);
395 if (retval) {
396 dev_err(&dev->udev->dev,
397 "Couldn't submit interrupt_in_urb %d\n", retval);
398 dev->interrupt_in_running = 0;
399 dev->open_count = 0;
400 goto unlock_exit;
401 }
402
403 /* save device in the file's private structure */
404 file->private_data = dev;
405
406unlock_exit:
407 mutex_unlock(&dev->lock);
408
409exit:
410 kfree(reset_reply);
411 return retval;
412}
413
414/**
415 * tower_release
416 */
417static int tower_release (struct inode *inode, struct file *file)
418{
419 struct lego_usb_tower *dev;
420 int retval = 0;
421
422 dev = file->private_data;
423
424 if (dev == NULL) {
425 retval = -ENODEV;
426 goto exit_nolock;
427 }
428
429 mutex_lock(&open_disc_mutex);
430 if (mutex_lock_interruptible(&dev->lock)) {
431 retval = -ERESTARTSYS;
432 goto exit;
433 }
434
435 if (dev->open_count != 1) {
436 dev_dbg(&dev->udev->dev, "%s: device not opened exactly once\n",
437 __func__);
438 retval = -ENODEV;
439 goto unlock_exit;
440 }
441 if (dev->udev == NULL) {
442 /* the device was unplugged before the file was released */
443
444 /* unlock here as tower_delete frees dev */
445 mutex_unlock(&dev->lock);
446 tower_delete (dev);
447 goto exit;
448 }
449
450 /* wait until write transfer is finished */
451 if (dev->interrupt_out_busy) {
452 wait_event_interruptible_timeout (dev->write_wait, !dev->interrupt_out_busy, 2 * HZ);
453 }
454 tower_abort_transfers (dev);
455 dev->open_count = 0;
456
457unlock_exit:
458 mutex_unlock(&dev->lock);
459
460exit:
461 mutex_unlock(&open_disc_mutex);
462exit_nolock:
463 return retval;
464}
465
466
467/**
468 * tower_abort_transfers
469 * aborts transfers and frees associated data structures
470 */
471static void tower_abort_transfers (struct lego_usb_tower *dev)
472{
473 if (dev == NULL)
474 return;
475
476 /* shutdown transfer */
477 if (dev->interrupt_in_running) {
478 dev->interrupt_in_running = 0;
479 mb();
480 if (dev->udev)
481 usb_kill_urb (dev->interrupt_in_urb);
482 }
483 if (dev->interrupt_out_busy && dev->udev)
484 usb_kill_urb(dev->interrupt_out_urb);
485}
486
487
488/**
489 * tower_check_for_read_packet
490 *
491 * To get correct semantics for signals and non-blocking I/O
492 * with packetizing we pretend not to see any data in the read buffer
493 * until it has been there unchanged for at least
494 * dev->packet_timeout_jiffies, or until the buffer is full.
495 */
496static void tower_check_for_read_packet (struct lego_usb_tower *dev)
497{
498 spin_lock_irq (&dev->read_buffer_lock);
499 if (!packet_timeout
500 || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
501 || dev->read_buffer_length == read_buffer_size) {
502 dev->read_packet_length = dev->read_buffer_length;
503 }
504 dev->interrupt_in_done = 0;
505 spin_unlock_irq (&dev->read_buffer_lock);
506}
507
508
509/**
510 * tower_poll
511 */
512static __poll_t tower_poll (struct file *file, poll_table *wait)
513{
514 struct lego_usb_tower *dev;
515 __poll_t mask = 0;
516
517 dev = file->private_data;
518
519 if (!dev->udev)
520 return EPOLLERR | EPOLLHUP;
521
522 poll_wait(file, &dev->read_wait, wait);
523 poll_wait(file, &dev->write_wait, wait);
524
525 tower_check_for_read_packet(dev);
526 if (dev->read_packet_length > 0) {
527 mask |= EPOLLIN | EPOLLRDNORM;
528 }
529 if (!dev->interrupt_out_busy) {
530 mask |= EPOLLOUT | EPOLLWRNORM;
531 }
532
533 return mask;
534}
535
536
537/**
538 * tower_llseek
539 */
540static loff_t tower_llseek (struct file *file, loff_t off, int whence)
541{
542 return -ESPIPE; /* unseekable */
543}
544
545
546/**
547 * tower_read
548 */
549static ssize_t tower_read (struct file *file, char __user *buffer, size_t count, loff_t *ppos)
550{
551 struct lego_usb_tower *dev;
552 size_t bytes_to_read;
553 int i;
554 int retval = 0;
555 unsigned long timeout = 0;
556
557 dev = file->private_data;
558
559 /* lock this object */
560 if (mutex_lock_interruptible(&dev->lock)) {
561 retval = -ERESTARTSYS;
562 goto exit;
563 }
564
565 /* verify that the device wasn't unplugged */
566 if (dev->udev == NULL) {
567 retval = -ENODEV;
568 pr_err("No device or device unplugged %d\n", retval);
569 goto unlock_exit;
570 }
571
572 /* verify that we actually have some data to read */
573 if (count == 0) {
574 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
575 goto unlock_exit;
576 }
577
578 if (read_timeout) {
579 timeout = jiffies + msecs_to_jiffies(read_timeout);
580 }
581
582 /* wait for data */
583 tower_check_for_read_packet (dev);
584 while (dev->read_packet_length == 0) {
585 if (file->f_flags & O_NONBLOCK) {
586 retval = -EAGAIN;
587 goto unlock_exit;
588 }
589 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
590 if (retval < 0) {
591 goto unlock_exit;
592 }
593
594 /* reset read timeout during read or write activity */
595 if (read_timeout
596 && (dev->read_buffer_length || dev->interrupt_out_busy)) {
597 timeout = jiffies + msecs_to_jiffies(read_timeout);
598 }
599 /* check for read timeout */
600 if (read_timeout && time_after (jiffies, timeout)) {
601 retval = -ETIMEDOUT;
602 goto unlock_exit;
603 }
604 tower_check_for_read_packet (dev);
605 }
606
607 /* copy the data from read_buffer into userspace */
608 bytes_to_read = min(count, dev->read_packet_length);
609
610 if (copy_to_user (buffer, dev->read_buffer, bytes_to_read)) {
611 retval = -EFAULT;
612 goto unlock_exit;
613 }
614
615 spin_lock_irq (&dev->read_buffer_lock);
616 dev->read_buffer_length -= bytes_to_read;
617 dev->read_packet_length -= bytes_to_read;
618 for (i=0; i<dev->read_buffer_length; i++) {
619 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
620 }
621 spin_unlock_irq (&dev->read_buffer_lock);
622
623 retval = bytes_to_read;
624
625unlock_exit:
626 /* unlock the device */
627 mutex_unlock(&dev->lock);
628
629exit:
630 return retval;
631}
632
633
634/**
635 * tower_write
636 */
637static ssize_t tower_write (struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
638{
639 struct lego_usb_tower *dev;
640 size_t bytes_to_write;
641 int retval = 0;
642
643 dev = file->private_data;
644
645 /* lock this object */
646 if (mutex_lock_interruptible(&dev->lock)) {
647 retval = -ERESTARTSYS;
648 goto exit;
649 }
650
651 /* verify that the device wasn't unplugged */
652 if (dev->udev == NULL) {
653 retval = -ENODEV;
654 pr_err("No device or device unplugged %d\n", retval);
655 goto unlock_exit;
656 }
657
658 /* verify that we actually have some data to write */
659 if (count == 0) {
660 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
661 goto unlock_exit;
662 }
663
664 /* wait until previous transfer is finished */
665 while (dev->interrupt_out_busy) {
666 if (file->f_flags & O_NONBLOCK) {
667 retval = -EAGAIN;
668 goto unlock_exit;
669 }
670 retval = wait_event_interruptible (dev->write_wait, !dev->interrupt_out_busy);
671 if (retval) {
672 goto unlock_exit;
673 }
674 }
675
676 /* write the data into interrupt_out_buffer from userspace */
677 bytes_to_write = min_t(int, count, write_buffer_size);
678 dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
679 __func__, count, bytes_to_write);
680
681 if (copy_from_user (dev->interrupt_out_buffer, buffer, bytes_to_write)) {
682 retval = -EFAULT;
683 goto unlock_exit;
684 }
685
686 /* send off the urb */
687 usb_fill_int_urb(dev->interrupt_out_urb,
688 dev->udev,
689 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
690 dev->interrupt_out_buffer,
691 bytes_to_write,
692 tower_interrupt_out_callback,
693 dev,
694 dev->interrupt_out_interval);
695
696 dev->interrupt_out_busy = 1;
697 wmb();
698
699 retval = usb_submit_urb (dev->interrupt_out_urb, GFP_KERNEL);
700 if (retval) {
701 dev->interrupt_out_busy = 0;
702 dev_err(&dev->udev->dev,
703 "Couldn't submit interrupt_out_urb %d\n", retval);
704 goto unlock_exit;
705 }
706 retval = bytes_to_write;
707
708unlock_exit:
709 /* unlock the device */
710 mutex_unlock(&dev->lock);
711
712exit:
713 return retval;
714}
715
716
717/**
718 * tower_interrupt_in_callback
719 */
720static void tower_interrupt_in_callback (struct urb *urb)
721{
722 struct lego_usb_tower *dev = urb->context;
723 int status = urb->status;
724 int retval;
725
726 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
727 urb->actual_length, urb->transfer_buffer);
728
729 if (status) {
730 if (status == -ENOENT ||
731 status == -ECONNRESET ||
732 status == -ESHUTDOWN) {
733 goto exit;
734 } else {
735 dev_dbg(&dev->udev->dev,
736 "%s: nonzero status received: %d\n", __func__,
737 status);
738 goto resubmit; /* maybe we can recover */
739 }
740 }
741
742 if (urb->actual_length > 0) {
743 spin_lock (&dev->read_buffer_lock);
744 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
745 memcpy (dev->read_buffer + dev->read_buffer_length,
746 dev->interrupt_in_buffer,
747 urb->actual_length);
748 dev->read_buffer_length += urb->actual_length;
749 dev->read_last_arrival = jiffies;
750 dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
751 __func__, urb->actual_length);
752 } else {
753 pr_warn("read_buffer overflow, %d bytes dropped\n",
754 urb->actual_length);
755 }
756 spin_unlock (&dev->read_buffer_lock);
757 }
758
759resubmit:
760 /* resubmit if we're still running */
761 if (dev->interrupt_in_running && dev->udev) {
762 retval = usb_submit_urb (dev->interrupt_in_urb, GFP_ATOMIC);
763 if (retval)
764 dev_err(&dev->udev->dev,
765 "%s: usb_submit_urb failed (%d)\n",
766 __func__, retval);
767 }
768
769exit:
770 dev->interrupt_in_done = 1;
771 wake_up_interruptible (&dev->read_wait);
772}
773
774
775/**
776 * tower_interrupt_out_callback
777 */
778static void tower_interrupt_out_callback (struct urb *urb)
779{
780 struct lego_usb_tower *dev = urb->context;
781 int status = urb->status;
782
783 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
784 urb->actual_length, urb->transfer_buffer);
785
786 /* sync/async unlink faults aren't errors */
787 if (status && !(status == -ENOENT ||
788 status == -ECONNRESET ||
789 status == -ESHUTDOWN)) {
790 dev_dbg(&dev->udev->dev,
791 "%s: nonzero write bulk status received: %d\n", __func__,
792 status);
793 }
794
795 dev->interrupt_out_busy = 0;
796 wake_up_interruptible(&dev->write_wait);
797}
798
799
800/**
801 * tower_probe
802 *
803 * Called by the usb core when a new device is connected that it thinks
804 * this driver might be interested in.
805 */
806static int tower_probe (struct usb_interface *interface, const struct usb_device_id *id)
807{
808 struct device *idev = &interface->dev;
809 struct usb_device *udev = interface_to_usbdev(interface);
810 struct lego_usb_tower *dev = NULL;
811 struct tower_get_version_reply *get_version_reply = NULL;
812 int retval = -ENOMEM;
813 int result;
814
815 /* allocate memory for our device state and initialize it */
816
817 dev = kmalloc (sizeof(struct lego_usb_tower), GFP_KERNEL);
818
819 if (!dev)
820 goto exit;
821
822 mutex_init(&dev->lock);
823
824 dev->udev = udev;
825 dev->open_count = 0;
826
827 dev->read_buffer = NULL;
828 dev->read_buffer_length = 0;
829 dev->read_packet_length = 0;
830 spin_lock_init (&dev->read_buffer_lock);
831 dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
832 dev->read_last_arrival = jiffies;
833
834 init_waitqueue_head (&dev->read_wait);
835 init_waitqueue_head (&dev->write_wait);
836
837 dev->interrupt_in_buffer = NULL;
838 dev->interrupt_in_endpoint = NULL;
839 dev->interrupt_in_urb = NULL;
840 dev->interrupt_in_running = 0;
841 dev->interrupt_in_done = 0;
842
843 dev->interrupt_out_buffer = NULL;
844 dev->interrupt_out_endpoint = NULL;
845 dev->interrupt_out_urb = NULL;
846 dev->interrupt_out_busy = 0;
847
848 result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
849 NULL, NULL,
850 &dev->interrupt_in_endpoint,
851 &dev->interrupt_out_endpoint);
852 if (result) {
853 dev_err(idev, "interrupt endpoints not found\n");
854 retval = result;
855 goto error;
856 }
857
858 dev->read_buffer = kmalloc (read_buffer_size, GFP_KERNEL);
859 if (!dev->read_buffer)
860 goto error;
861 dev->interrupt_in_buffer = kmalloc (usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
862 if (!dev->interrupt_in_buffer)
863 goto error;
864 dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
865 if (!dev->interrupt_in_urb)
866 goto error;
867 dev->interrupt_out_buffer = kmalloc (write_buffer_size, GFP_KERNEL);
868 if (!dev->interrupt_out_buffer)
869 goto error;
870 dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
871 if (!dev->interrupt_out_urb)
872 goto error;
873 dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
874 dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
875
876 get_version_reply = kmalloc(sizeof(*get_version_reply), GFP_KERNEL);
877
878 if (!get_version_reply) {
879 retval = -ENOMEM;
880 goto error;
881 }
882
883 /* get the firmware version and log it */
884 result = usb_control_msg (udev,
885 usb_rcvctrlpipe(udev, 0),
886 LEGO_USB_TOWER_REQUEST_GET_VERSION,
887 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
888 0,
889 0,
890 get_version_reply,
891 sizeof(*get_version_reply),
892 1000);
893 if (result < 0) {
894 dev_err(idev, "LEGO USB Tower get version control request failed\n");
895 retval = result;
896 goto error;
897 }
898 dev_info(&interface->dev,
899 "LEGO USB Tower firmware version is %d.%d build %d\n",
900 get_version_reply->major,
901 get_version_reply->minor,
902 le16_to_cpu(get_version_reply->build_no));
903
904 /* we can register the device now, as it is ready */
905 usb_set_intfdata (interface, dev);
906
907 retval = usb_register_dev (interface, &tower_class);
908
909 if (retval) {
910 /* something prevented us from registering this driver */
911 dev_err(idev, "Not able to get a minor for this device.\n");
912 usb_set_intfdata (interface, NULL);
913 goto error;
914 }
915 dev->minor = interface->minor;
916
917 /* let the user know what node this device is now attached to */
918 dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
919 "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
920 USB_MAJOR, dev->minor);
921
922exit:
923 kfree(get_version_reply);
924 return retval;
925
926error:
927 kfree(get_version_reply);
928 tower_delete(dev);
929 return retval;
930}
931
932
933/**
934 * tower_disconnect
935 *
936 * Called by the usb core when the device is removed from the system.
937 */
938static void tower_disconnect (struct usb_interface *interface)
939{
940 struct lego_usb_tower *dev;
941 int minor;
942
943 dev = usb_get_intfdata (interface);
944 mutex_lock(&open_disc_mutex);
945 usb_set_intfdata (interface, NULL);
946
947 minor = dev->minor;
948
949 /* give back our minor */
950 usb_deregister_dev (interface, &tower_class);
951
952 mutex_lock(&dev->lock);
953 mutex_unlock(&open_disc_mutex);
954
955 /* if the device is not opened, then we clean up right now */
956 if (!dev->open_count) {
957 mutex_unlock(&dev->lock);
958 tower_delete (dev);
959 } else {
960 dev->udev = NULL;
961 /* wake up pollers */
962 wake_up_interruptible_all(&dev->read_wait);
963 wake_up_interruptible_all(&dev->write_wait);
964 mutex_unlock(&dev->lock);
965 }
966
967 dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
968 (minor - LEGO_USB_TOWER_MINOR_BASE));
969}
970
971module_usb_driver(tower_driver);
972
973MODULE_AUTHOR(DRIVER_AUTHOR);
974MODULE_DESCRIPTION(DRIVER_DESC);
975#ifdef MODULE_LICENSE
976MODULE_LICENSE("GPL");
977#endif