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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;
161 __u8 err_code;
162 __u8 spare;
163};
164
165struct tower_get_version_reply {
166 __le16 size;
167 __u8 err_code;
168 __u8 spare;
169 __u8 major;
170 __u8 minor;
171 __le16 build_no;
172};
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_done;
210
211 char *interrupt_out_buffer;
212 struct usb_endpoint_descriptor *interrupt_out_endpoint;
213 struct urb *interrupt_out_urb;
214 int interrupt_out_interval;
215 int interrupt_out_busy;
216
217};
218
219
220/* local function prototypes */
221static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos);
222static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
223static inline void tower_delete(struct lego_usb_tower *dev);
224static int tower_open(struct inode *inode, struct file *file);
225static int tower_release(struct inode *inode, struct file *file);
226static __poll_t tower_poll(struct file *file, poll_table *wait);
227static loff_t tower_llseek(struct file *file, loff_t off, int whence);
228
229static void tower_check_for_read_packet(struct lego_usb_tower *dev);
230static void tower_interrupt_in_callback(struct urb *urb);
231static void tower_interrupt_out_callback(struct urb *urb);
232
233static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id);
234static void tower_disconnect(struct usb_interface *interface);
235
236
237/* file operations needed when we register this driver */
238static const struct file_operations tower_fops = {
239 .owner = THIS_MODULE,
240 .read = tower_read,
241 .write = tower_write,
242 .open = tower_open,
243 .release = tower_release,
244 .poll = tower_poll,
245 .llseek = tower_llseek,
246};
247
248static char *legousbtower_devnode(struct device *dev, umode_t *mode)
249{
250 return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
251}
252
253/*
254 * usb class driver info in order to get a minor number from the usb core,
255 * and to have the device registered with the driver core
256 */
257static struct usb_class_driver tower_class = {
258 .name = "legousbtower%d",
259 .devnode = legousbtower_devnode,
260 .fops = &tower_fops,
261 .minor_base = LEGO_USB_TOWER_MINOR_BASE,
262};
263
264
265/* usb specific object needed to register this driver with the usb subsystem */
266static struct usb_driver tower_driver = {
267 .name = "legousbtower",
268 .probe = tower_probe,
269 .disconnect = tower_disconnect,
270 .id_table = tower_table,
271};
272
273
274/*
275 * lego_usb_tower_debug_data
276 */
277static inline void lego_usb_tower_debug_data(struct device *dev,
278 const char *function, int size,
279 const unsigned char *data)
280{
281 dev_dbg(dev, "%s - length = %d, data = %*ph\n",
282 function, size, size, data);
283}
284
285
286/*
287 * tower_delete
288 */
289static inline void tower_delete(struct lego_usb_tower *dev)
290{
291 /* free data structures */
292 usb_free_urb(dev->interrupt_in_urb);
293 usb_free_urb(dev->interrupt_out_urb);
294 kfree(dev->read_buffer);
295 kfree(dev->interrupt_in_buffer);
296 kfree(dev->interrupt_out_buffer);
297 usb_put_dev(dev->udev);
298 kfree(dev);
299}
300
301
302/*
303 * tower_open
304 */
305static int tower_open(struct inode *inode, struct file *file)
306{
307 struct lego_usb_tower *dev = NULL;
308 int subminor;
309 int retval = 0;
310 struct usb_interface *interface;
311 struct tower_reset_reply *reset_reply;
312 int result;
313
314 reset_reply = kmalloc(sizeof(*reset_reply), GFP_KERNEL);
315 if (!reset_reply) {
316 retval = -ENOMEM;
317 goto exit;
318 }
319
320 nonseekable_open(inode, file);
321 subminor = iminor(inode);
322
323 interface = usb_find_interface(&tower_driver, subminor);
324 if (!interface) {
325 pr_err("error, can't find device for minor %d\n", subminor);
326 retval = -ENODEV;
327 goto exit;
328 }
329
330 dev = usb_get_intfdata(interface);
331 if (!dev) {
332 retval = -ENODEV;
333 goto exit;
334 }
335
336 /* lock this device */
337 if (mutex_lock_interruptible(&dev->lock)) {
338 retval = -ERESTARTSYS;
339 goto exit;
340 }
341
342
343 /* allow opening only once */
344 if (dev->open_count) {
345 retval = -EBUSY;
346 goto unlock_exit;
347 }
348
349 /* reset the tower */
350 result = usb_control_msg(dev->udev,
351 usb_rcvctrlpipe(dev->udev, 0),
352 LEGO_USB_TOWER_REQUEST_RESET,
353 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
354 0,
355 0,
356 reset_reply,
357 sizeof(*reset_reply),
358 1000);
359 if (result < 0) {
360 dev_err(&dev->udev->dev,
361 "LEGO USB Tower reset control request failed\n");
362 retval = result;
363 goto unlock_exit;
364 }
365
366 /* initialize in direction */
367 dev->read_buffer_length = 0;
368 dev->read_packet_length = 0;
369 usb_fill_int_urb(dev->interrupt_in_urb,
370 dev->udev,
371 usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
372 dev->interrupt_in_buffer,
373 usb_endpoint_maxp(dev->interrupt_in_endpoint),
374 tower_interrupt_in_callback,
375 dev,
376 dev->interrupt_in_interval);
377
378 dev->interrupt_in_done = 0;
379 mb();
380
381 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
382 if (retval) {
383 dev_err(&dev->udev->dev,
384 "Couldn't submit interrupt_in_urb %d\n", retval);
385 goto unlock_exit;
386 }
387
388 /* save device in the file's private structure */
389 file->private_data = dev;
390
391 dev->open_count = 1;
392
393unlock_exit:
394 mutex_unlock(&dev->lock);
395
396exit:
397 kfree(reset_reply);
398 return retval;
399}
400
401/*
402 * tower_release
403 */
404static int tower_release(struct inode *inode, struct file *file)
405{
406 struct lego_usb_tower *dev;
407 int retval = 0;
408
409 dev = file->private_data;
410 if (dev == NULL) {
411 retval = -ENODEV;
412 goto exit;
413 }
414
415 mutex_lock(&dev->lock);
416
417 if (dev->disconnected) {
418 /* the device was unplugged before the file was released */
419
420 /* unlock here as tower_delete frees dev */
421 mutex_unlock(&dev->lock);
422 tower_delete(dev);
423 goto exit;
424 }
425
426 /* wait until write transfer is finished */
427 if (dev->interrupt_out_busy) {
428 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy,
429 2 * HZ);
430 }
431
432 /* shutdown transfers */
433 usb_kill_urb(dev->interrupt_in_urb);
434 usb_kill_urb(dev->interrupt_out_urb);
435
436 dev->open_count = 0;
437
438 mutex_unlock(&dev->lock);
439exit:
440 return retval;
441}
442
443/*
444 * tower_check_for_read_packet
445 *
446 * To get correct semantics for signals and non-blocking I/O
447 * with packetizing we pretend not to see any data in the read buffer
448 * until it has been there unchanged for at least
449 * dev->packet_timeout_jiffies, or until the buffer is full.
450 */
451static void tower_check_for_read_packet(struct lego_usb_tower *dev)
452{
453 spin_lock_irq(&dev->read_buffer_lock);
454 if (!packet_timeout
455 || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
456 || dev->read_buffer_length == read_buffer_size) {
457 dev->read_packet_length = dev->read_buffer_length;
458 }
459 dev->interrupt_in_done = 0;
460 spin_unlock_irq(&dev->read_buffer_lock);
461}
462
463
464/*
465 * tower_poll
466 */
467static __poll_t tower_poll(struct file *file, poll_table *wait)
468{
469 struct lego_usb_tower *dev;
470 __poll_t mask = 0;
471
472 dev = file->private_data;
473
474 if (dev->disconnected)
475 return EPOLLERR | EPOLLHUP;
476
477 poll_wait(file, &dev->read_wait, wait);
478 poll_wait(file, &dev->write_wait, wait);
479
480 tower_check_for_read_packet(dev);
481 if (dev->read_packet_length > 0)
482 mask |= EPOLLIN | EPOLLRDNORM;
483 if (!dev->interrupt_out_busy)
484 mask |= EPOLLOUT | EPOLLWRNORM;
485
486 return mask;
487}
488
489
490/*
491 * tower_llseek
492 */
493static loff_t tower_llseek(struct file *file, loff_t off, int whence)
494{
495 return -ESPIPE; /* unseekable */
496}
497
498
499/*
500 * tower_read
501 */
502static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
503{
504 struct lego_usb_tower *dev;
505 size_t bytes_to_read;
506 int i;
507 int retval = 0;
508 unsigned long timeout = 0;
509
510 dev = file->private_data;
511
512 /* lock this object */
513 if (mutex_lock_interruptible(&dev->lock)) {
514 retval = -ERESTARTSYS;
515 goto exit;
516 }
517
518 /* verify that the device wasn't unplugged */
519 if (dev->disconnected) {
520 retval = -ENODEV;
521 goto unlock_exit;
522 }
523
524 /* verify that we actually have some data to read */
525 if (count == 0) {
526 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
527 goto unlock_exit;
528 }
529
530 if (read_timeout)
531 timeout = jiffies + msecs_to_jiffies(read_timeout);
532
533 /* wait for data */
534 tower_check_for_read_packet(dev);
535 while (dev->read_packet_length == 0) {
536 if (file->f_flags & O_NONBLOCK) {
537 retval = -EAGAIN;
538 goto unlock_exit;
539 }
540 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
541 if (retval < 0)
542 goto unlock_exit;
543
544 /* reset read timeout during read or write activity */
545 if (read_timeout
546 && (dev->read_buffer_length || dev->interrupt_out_busy)) {
547 timeout = jiffies + msecs_to_jiffies(read_timeout);
548 }
549 /* check for read timeout */
550 if (read_timeout && time_after(jiffies, timeout)) {
551 retval = -ETIMEDOUT;
552 goto unlock_exit;
553 }
554 tower_check_for_read_packet(dev);
555 }
556
557 /* copy the data from read_buffer into userspace */
558 bytes_to_read = min(count, dev->read_packet_length);
559
560 if (copy_to_user(buffer, dev->read_buffer, bytes_to_read)) {
561 retval = -EFAULT;
562 goto unlock_exit;
563 }
564
565 spin_lock_irq(&dev->read_buffer_lock);
566 dev->read_buffer_length -= bytes_to_read;
567 dev->read_packet_length -= bytes_to_read;
568 for (i = 0; i < dev->read_buffer_length; i++)
569 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
570 spin_unlock_irq(&dev->read_buffer_lock);
571
572 retval = bytes_to_read;
573
574unlock_exit:
575 /* unlock the device */
576 mutex_unlock(&dev->lock);
577
578exit:
579 return retval;
580}
581
582
583/*
584 * tower_write
585 */
586static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
587{
588 struct lego_usb_tower *dev;
589 size_t bytes_to_write;
590 int retval = 0;
591
592 dev = file->private_data;
593
594 /* lock this object */
595 if (mutex_lock_interruptible(&dev->lock)) {
596 retval = -ERESTARTSYS;
597 goto exit;
598 }
599
600 /* verify that the device wasn't unplugged */
601 if (dev->disconnected) {
602 retval = -ENODEV;
603 goto unlock_exit;
604 }
605
606 /* verify that we actually have some data to write */
607 if (count == 0) {
608 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
609 goto unlock_exit;
610 }
611
612 /* wait until previous transfer is finished */
613 while (dev->interrupt_out_busy) {
614 if (file->f_flags & O_NONBLOCK) {
615 retval = -EAGAIN;
616 goto unlock_exit;
617 }
618 retval = wait_event_interruptible(dev->write_wait,
619 !dev->interrupt_out_busy);
620 if (retval)
621 goto unlock_exit;
622 }
623
624 /* write the data into interrupt_out_buffer from userspace */
625 bytes_to_write = min_t(int, count, write_buffer_size);
626 dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
627 __func__, count, bytes_to_write);
628
629 if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
630 retval = -EFAULT;
631 goto unlock_exit;
632 }
633
634 /* send off the urb */
635 usb_fill_int_urb(dev->interrupt_out_urb,
636 dev->udev,
637 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
638 dev->interrupt_out_buffer,
639 bytes_to_write,
640 tower_interrupt_out_callback,
641 dev,
642 dev->interrupt_out_interval);
643
644 dev->interrupt_out_busy = 1;
645 wmb();
646
647 retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
648 if (retval) {
649 dev->interrupt_out_busy = 0;
650 dev_err(&dev->udev->dev,
651 "Couldn't submit interrupt_out_urb %d\n", retval);
652 goto unlock_exit;
653 }
654 retval = bytes_to_write;
655
656unlock_exit:
657 /* unlock the device */
658 mutex_unlock(&dev->lock);
659
660exit:
661 return retval;
662}
663
664
665/*
666 * tower_interrupt_in_callback
667 */
668static void tower_interrupt_in_callback(struct urb *urb)
669{
670 struct lego_usb_tower *dev = urb->context;
671 int status = urb->status;
672 int retval;
673 unsigned long flags;
674
675 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
676 urb->actual_length, urb->transfer_buffer);
677
678 if (status) {
679 if (status == -ENOENT ||
680 status == -ECONNRESET ||
681 status == -ESHUTDOWN) {
682 goto exit;
683 } else {
684 dev_dbg(&dev->udev->dev,
685 "%s: nonzero status received: %d\n", __func__,
686 status);
687 goto resubmit; /* maybe we can recover */
688 }
689 }
690
691 if (urb->actual_length > 0) {
692 spin_lock_irqsave(&dev->read_buffer_lock, flags);
693 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
694 memcpy(dev->read_buffer + dev->read_buffer_length,
695 dev->interrupt_in_buffer,
696 urb->actual_length);
697 dev->read_buffer_length += urb->actual_length;
698 dev->read_last_arrival = jiffies;
699 dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
700 __func__, urb->actual_length);
701 } else {
702 pr_warn("read_buffer overflow, %d bytes dropped\n",
703 urb->actual_length);
704 }
705 spin_unlock_irqrestore(&dev->read_buffer_lock, flags);
706 }
707
708resubmit:
709 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
710 if (retval) {
711 dev_err(&dev->udev->dev, "%s: usb_submit_urb failed (%d)\n",
712 __func__, retval);
713 }
714exit:
715 dev->interrupt_in_done = 1;
716 wake_up_interruptible(&dev->read_wait);
717}
718
719
720/*
721 * tower_interrupt_out_callback
722 */
723static void tower_interrupt_out_callback(struct urb *urb)
724{
725 struct lego_usb_tower *dev = urb->context;
726 int status = urb->status;
727
728 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
729 urb->actual_length, urb->transfer_buffer);
730
731 /* sync/async unlink faults aren't errors */
732 if (status && !(status == -ENOENT ||
733 status == -ECONNRESET ||
734 status == -ESHUTDOWN)) {
735 dev_dbg(&dev->udev->dev,
736 "%s: nonzero write bulk status received: %d\n", __func__,
737 status);
738 }
739
740 dev->interrupt_out_busy = 0;
741 wake_up_interruptible(&dev->write_wait);
742}
743
744
745/*
746 * tower_probe
747 *
748 * Called by the usb core when a new device is connected that it thinks
749 * this driver might be interested in.
750 */
751static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id)
752{
753 struct device *idev = &interface->dev;
754 struct usb_device *udev = interface_to_usbdev(interface);
755 struct lego_usb_tower *dev;
756 struct tower_get_version_reply *get_version_reply = NULL;
757 int retval = -ENOMEM;
758 int result;
759
760 /* allocate memory for our device state and initialize it */
761 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
762 if (!dev)
763 goto exit;
764
765 mutex_init(&dev->lock);
766 dev->udev = usb_get_dev(udev);
767 spin_lock_init(&dev->read_buffer_lock);
768 dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
769 dev->read_last_arrival = jiffies;
770 init_waitqueue_head(&dev->read_wait);
771 init_waitqueue_head(&dev->write_wait);
772
773 result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
774 NULL, NULL,
775 &dev->interrupt_in_endpoint,
776 &dev->interrupt_out_endpoint);
777 if (result) {
778 dev_err(idev, "interrupt endpoints not found\n");
779 retval = result;
780 goto error;
781 }
782
783 dev->read_buffer = kmalloc(read_buffer_size, GFP_KERNEL);
784 if (!dev->read_buffer)
785 goto error;
786 dev->interrupt_in_buffer = kmalloc(usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
787 if (!dev->interrupt_in_buffer)
788 goto error;
789 dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
790 if (!dev->interrupt_in_urb)
791 goto error;
792 dev->interrupt_out_buffer = kmalloc(write_buffer_size, GFP_KERNEL);
793 if (!dev->interrupt_out_buffer)
794 goto error;
795 dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
796 if (!dev->interrupt_out_urb)
797 goto error;
798 dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
799 dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
800
801 get_version_reply = kmalloc(sizeof(*get_version_reply), GFP_KERNEL);
802 if (!get_version_reply) {
803 retval = -ENOMEM;
804 goto error;
805 }
806
807 /* get the firmware version and log it */
808 result = usb_control_msg(udev,
809 usb_rcvctrlpipe(udev, 0),
810 LEGO_USB_TOWER_REQUEST_GET_VERSION,
811 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
812 0,
813 0,
814 get_version_reply,
815 sizeof(*get_version_reply),
816 1000);
817 if (result != sizeof(*get_version_reply)) {
818 if (result >= 0)
819 result = -EIO;
820 dev_err(idev, "get version request failed: %d\n", result);
821 retval = result;
822 goto error;
823 }
824 dev_info(&interface->dev,
825 "LEGO USB Tower firmware version is %d.%d build %d\n",
826 get_version_reply->major,
827 get_version_reply->minor,
828 le16_to_cpu(get_version_reply->build_no));
829
830 /* we can register the device now, as it is ready */
831 usb_set_intfdata(interface, dev);
832
833 retval = usb_register_dev(interface, &tower_class);
834 if (retval) {
835 /* something prevented us from registering this driver */
836 dev_err(idev, "Not able to get a minor for this device.\n");
837 goto error;
838 }
839 dev->minor = interface->minor;
840
841 /* let the user know what node this device is now attached to */
842 dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
843 "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
844 USB_MAJOR, dev->minor);
845
846exit:
847 kfree(get_version_reply);
848 return retval;
849
850error:
851 kfree(get_version_reply);
852 tower_delete(dev);
853 return retval;
854}
855
856
857/*
858 * tower_disconnect
859 *
860 * Called by the usb core when the device is removed from the system.
861 */
862static void tower_disconnect(struct usb_interface *interface)
863{
864 struct lego_usb_tower *dev;
865 int minor;
866
867 dev = usb_get_intfdata(interface);
868
869 minor = dev->minor;
870
871 /* give back our minor and prevent further open() */
872 usb_deregister_dev(interface, &tower_class);
873
874 /* stop I/O */
875 usb_poison_urb(dev->interrupt_in_urb);
876 usb_poison_urb(dev->interrupt_out_urb);
877
878 mutex_lock(&dev->lock);
879
880 /* if the device is not opened, then we clean up right now */
881 if (!dev->open_count) {
882 mutex_unlock(&dev->lock);
883 tower_delete(dev);
884 } else {
885 dev->disconnected = 1;
886 /* wake up pollers */
887 wake_up_interruptible_all(&dev->read_wait);
888 wake_up_interruptible_all(&dev->write_wait);
889 mutex_unlock(&dev->lock);
890 }
891
892 dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
893 (minor - LEGO_USB_TOWER_MINOR_BASE));
894}
895
896module_usb_driver(tower_driver);
897
898MODULE_AUTHOR(DRIVER_AUTHOR);
899MODULE_DESCRIPTION(DRIVER_DESC);
900MODULE_LICENSE("GPL");
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;
161 __u8 err_code;
162 __u8 spare;
163};
164
165struct tower_get_version_reply {
166 __le16 size;
167 __u8 err_code;
168 __u8 spare;
169 __u8 major;
170 __u8 minor;
171 __le16 build_no;
172};
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_done;
210
211 char *interrupt_out_buffer;
212 struct usb_endpoint_descriptor *interrupt_out_endpoint;
213 struct urb *interrupt_out_urb;
214 int interrupt_out_interval;
215 int interrupt_out_busy;
216
217};
218
219
220/* local function prototypes */
221static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos);
222static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos);
223static inline void tower_delete(struct lego_usb_tower *dev);
224static int tower_open(struct inode *inode, struct file *file);
225static int tower_release(struct inode *inode, struct file *file);
226static __poll_t tower_poll(struct file *file, poll_table *wait);
227static loff_t tower_llseek(struct file *file, loff_t off, int whence);
228
229static void tower_check_for_read_packet(struct lego_usb_tower *dev);
230static void tower_interrupt_in_callback(struct urb *urb);
231static void tower_interrupt_out_callback(struct urb *urb);
232
233static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id);
234static void tower_disconnect(struct usb_interface *interface);
235
236
237/* file operations needed when we register this driver */
238static const struct file_operations tower_fops = {
239 .owner = THIS_MODULE,
240 .read = tower_read,
241 .write = tower_write,
242 .open = tower_open,
243 .release = tower_release,
244 .poll = tower_poll,
245 .llseek = tower_llseek,
246};
247
248static char *legousbtower_devnode(const struct device *dev, umode_t *mode)
249{
250 return kasprintf(GFP_KERNEL, "usb/%s", dev_name(dev));
251}
252
253/*
254 * usb class driver info in order to get a minor number from the usb core,
255 * and to have the device registered with the driver core
256 */
257static struct usb_class_driver tower_class = {
258 .name = "legousbtower%d",
259 .devnode = legousbtower_devnode,
260 .fops = &tower_fops,
261 .minor_base = LEGO_USB_TOWER_MINOR_BASE,
262};
263
264
265/* usb specific object needed to register this driver with the usb subsystem */
266static struct usb_driver tower_driver = {
267 .name = "legousbtower",
268 .probe = tower_probe,
269 .disconnect = tower_disconnect,
270 .id_table = tower_table,
271};
272
273
274/*
275 * lego_usb_tower_debug_data
276 */
277static inline void lego_usb_tower_debug_data(struct device *dev,
278 const char *function, int size,
279 const unsigned char *data)
280{
281 dev_dbg(dev, "%s - length = %d, data = %*ph\n",
282 function, size, size, data);
283}
284
285
286/*
287 * tower_delete
288 */
289static inline void tower_delete(struct lego_usb_tower *dev)
290{
291 /* free data structures */
292 usb_free_urb(dev->interrupt_in_urb);
293 usb_free_urb(dev->interrupt_out_urb);
294 kfree(dev->read_buffer);
295 kfree(dev->interrupt_in_buffer);
296 kfree(dev->interrupt_out_buffer);
297 usb_put_dev(dev->udev);
298 kfree(dev);
299}
300
301
302/*
303 * tower_open
304 */
305static int tower_open(struct inode *inode, struct file *file)
306{
307 struct lego_usb_tower *dev = NULL;
308 int subminor;
309 int retval = 0;
310 struct usb_interface *interface;
311 struct tower_reset_reply reset_reply;
312 int result;
313
314 nonseekable_open(inode, file);
315 subminor = iminor(inode);
316
317 interface = usb_find_interface(&tower_driver, subminor);
318 if (!interface) {
319 pr_err("error, can't find device for minor %d\n", subminor);
320 retval = -ENODEV;
321 goto exit;
322 }
323
324 dev = usb_get_intfdata(interface);
325 if (!dev) {
326 retval = -ENODEV;
327 goto exit;
328 }
329
330 /* lock this device */
331 if (mutex_lock_interruptible(&dev->lock)) {
332 retval = -ERESTARTSYS;
333 goto exit;
334 }
335
336
337 /* allow opening only once */
338 if (dev->open_count) {
339 retval = -EBUSY;
340 goto unlock_exit;
341 }
342
343 /* reset the tower */
344 result = usb_control_msg_recv(dev->udev, 0,
345 LEGO_USB_TOWER_REQUEST_RESET,
346 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
347 0, 0,
348 &reset_reply, sizeof(reset_reply), 1000,
349 GFP_KERNEL);
350 if (result < 0) {
351 dev_err(&dev->udev->dev,
352 "LEGO USB Tower reset control request failed\n");
353 retval = result;
354 goto unlock_exit;
355 }
356
357 /* initialize in direction */
358 dev->read_buffer_length = 0;
359 dev->read_packet_length = 0;
360 usb_fill_int_urb(dev->interrupt_in_urb,
361 dev->udev,
362 usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress),
363 dev->interrupt_in_buffer,
364 usb_endpoint_maxp(dev->interrupt_in_endpoint),
365 tower_interrupt_in_callback,
366 dev,
367 dev->interrupt_in_interval);
368
369 dev->interrupt_in_done = 0;
370 mb();
371
372 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_KERNEL);
373 if (retval) {
374 dev_err(&dev->udev->dev,
375 "Couldn't submit interrupt_in_urb %d\n", retval);
376 goto unlock_exit;
377 }
378
379 /* save device in the file's private structure */
380 file->private_data = dev;
381
382 dev->open_count = 1;
383
384unlock_exit:
385 mutex_unlock(&dev->lock);
386
387exit:
388 return retval;
389}
390
391/*
392 * tower_release
393 */
394static int tower_release(struct inode *inode, struct file *file)
395{
396 struct lego_usb_tower *dev;
397 int retval = 0;
398
399 dev = file->private_data;
400 if (dev == NULL) {
401 retval = -ENODEV;
402 goto exit;
403 }
404
405 mutex_lock(&dev->lock);
406
407 if (dev->disconnected) {
408 /* the device was unplugged before the file was released */
409
410 /* unlock here as tower_delete frees dev */
411 mutex_unlock(&dev->lock);
412 tower_delete(dev);
413 goto exit;
414 }
415
416 /* wait until write transfer is finished */
417 if (dev->interrupt_out_busy) {
418 wait_event_interruptible_timeout(dev->write_wait, !dev->interrupt_out_busy,
419 2 * HZ);
420 }
421
422 /* shutdown transfers */
423 usb_kill_urb(dev->interrupt_in_urb);
424 usb_kill_urb(dev->interrupt_out_urb);
425
426 dev->open_count = 0;
427
428 mutex_unlock(&dev->lock);
429exit:
430 return retval;
431}
432
433/*
434 * tower_check_for_read_packet
435 *
436 * To get correct semantics for signals and non-blocking I/O
437 * with packetizing we pretend not to see any data in the read buffer
438 * until it has been there unchanged for at least
439 * dev->packet_timeout_jiffies, or until the buffer is full.
440 */
441static void tower_check_for_read_packet(struct lego_usb_tower *dev)
442{
443 spin_lock_irq(&dev->read_buffer_lock);
444 if (!packet_timeout
445 || time_after(jiffies, dev->read_last_arrival + dev->packet_timeout_jiffies)
446 || dev->read_buffer_length == read_buffer_size) {
447 dev->read_packet_length = dev->read_buffer_length;
448 }
449 dev->interrupt_in_done = 0;
450 spin_unlock_irq(&dev->read_buffer_lock);
451}
452
453
454/*
455 * tower_poll
456 */
457static __poll_t tower_poll(struct file *file, poll_table *wait)
458{
459 struct lego_usb_tower *dev;
460 __poll_t mask = 0;
461
462 dev = file->private_data;
463
464 if (dev->disconnected)
465 return EPOLLERR | EPOLLHUP;
466
467 poll_wait(file, &dev->read_wait, wait);
468 poll_wait(file, &dev->write_wait, wait);
469
470 tower_check_for_read_packet(dev);
471 if (dev->read_packet_length > 0)
472 mask |= EPOLLIN | EPOLLRDNORM;
473 if (!dev->interrupt_out_busy)
474 mask |= EPOLLOUT | EPOLLWRNORM;
475
476 return mask;
477}
478
479
480/*
481 * tower_llseek
482 */
483static loff_t tower_llseek(struct file *file, loff_t off, int whence)
484{
485 return -ESPIPE; /* unseekable */
486}
487
488
489/*
490 * tower_read
491 */
492static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
493{
494 struct lego_usb_tower *dev;
495 size_t bytes_to_read;
496 int i;
497 int retval = 0;
498 unsigned long timeout = 0;
499
500 dev = file->private_data;
501
502 /* lock this object */
503 if (mutex_lock_interruptible(&dev->lock)) {
504 retval = -ERESTARTSYS;
505 goto exit;
506 }
507
508 /* verify that the device wasn't unplugged */
509 if (dev->disconnected) {
510 retval = -ENODEV;
511 goto unlock_exit;
512 }
513
514 /* verify that we actually have some data to read */
515 if (count == 0) {
516 dev_dbg(&dev->udev->dev, "read request of 0 bytes\n");
517 goto unlock_exit;
518 }
519
520 if (read_timeout)
521 timeout = jiffies + msecs_to_jiffies(read_timeout);
522
523 /* wait for data */
524 tower_check_for_read_packet(dev);
525 while (dev->read_packet_length == 0) {
526 if (file->f_flags & O_NONBLOCK) {
527 retval = -EAGAIN;
528 goto unlock_exit;
529 }
530 retval = wait_event_interruptible_timeout(dev->read_wait, dev->interrupt_in_done, dev->packet_timeout_jiffies);
531 if (retval < 0)
532 goto unlock_exit;
533
534 /* reset read timeout during read or write activity */
535 if (read_timeout
536 && (dev->read_buffer_length || dev->interrupt_out_busy)) {
537 timeout = jiffies + msecs_to_jiffies(read_timeout);
538 }
539 /* check for read timeout */
540 if (read_timeout && time_after(jiffies, timeout)) {
541 retval = -ETIMEDOUT;
542 goto unlock_exit;
543 }
544 tower_check_for_read_packet(dev);
545 }
546
547 /* copy the data from read_buffer into userspace */
548 bytes_to_read = min(count, dev->read_packet_length);
549
550 if (copy_to_user(buffer, dev->read_buffer, bytes_to_read)) {
551 retval = -EFAULT;
552 goto unlock_exit;
553 }
554
555 spin_lock_irq(&dev->read_buffer_lock);
556 dev->read_buffer_length -= bytes_to_read;
557 dev->read_packet_length -= bytes_to_read;
558 for (i = 0; i < dev->read_buffer_length; i++)
559 dev->read_buffer[i] = dev->read_buffer[i+bytes_to_read];
560 spin_unlock_irq(&dev->read_buffer_lock);
561
562 retval = bytes_to_read;
563
564unlock_exit:
565 /* unlock the device */
566 mutex_unlock(&dev->lock);
567
568exit:
569 return retval;
570}
571
572
573/*
574 * tower_write
575 */
576static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
577{
578 struct lego_usb_tower *dev;
579 size_t bytes_to_write;
580 int retval = 0;
581
582 dev = file->private_data;
583
584 /* lock this object */
585 if (mutex_lock_interruptible(&dev->lock)) {
586 retval = -ERESTARTSYS;
587 goto exit;
588 }
589
590 /* verify that the device wasn't unplugged */
591 if (dev->disconnected) {
592 retval = -ENODEV;
593 goto unlock_exit;
594 }
595
596 /* verify that we actually have some data to write */
597 if (count == 0) {
598 dev_dbg(&dev->udev->dev, "write request of 0 bytes\n");
599 goto unlock_exit;
600 }
601
602 /* wait until previous transfer is finished */
603 while (dev->interrupt_out_busy) {
604 if (file->f_flags & O_NONBLOCK) {
605 retval = -EAGAIN;
606 goto unlock_exit;
607 }
608 retval = wait_event_interruptible(dev->write_wait,
609 !dev->interrupt_out_busy);
610 if (retval)
611 goto unlock_exit;
612 }
613
614 /* write the data into interrupt_out_buffer from userspace */
615 bytes_to_write = min_t(int, count, write_buffer_size);
616 dev_dbg(&dev->udev->dev, "%s: count = %zd, bytes_to_write = %zd\n",
617 __func__, count, bytes_to_write);
618
619 if (copy_from_user(dev->interrupt_out_buffer, buffer, bytes_to_write)) {
620 retval = -EFAULT;
621 goto unlock_exit;
622 }
623
624 /* send off the urb */
625 usb_fill_int_urb(dev->interrupt_out_urb,
626 dev->udev,
627 usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress),
628 dev->interrupt_out_buffer,
629 bytes_to_write,
630 tower_interrupt_out_callback,
631 dev,
632 dev->interrupt_out_interval);
633
634 dev->interrupt_out_busy = 1;
635 wmb();
636
637 retval = usb_submit_urb(dev->interrupt_out_urb, GFP_KERNEL);
638 if (retval) {
639 dev->interrupt_out_busy = 0;
640 dev_err(&dev->udev->dev,
641 "Couldn't submit interrupt_out_urb %d\n", retval);
642 goto unlock_exit;
643 }
644 retval = bytes_to_write;
645
646unlock_exit:
647 /* unlock the device */
648 mutex_unlock(&dev->lock);
649
650exit:
651 return retval;
652}
653
654
655/*
656 * tower_interrupt_in_callback
657 */
658static void tower_interrupt_in_callback(struct urb *urb)
659{
660 struct lego_usb_tower *dev = urb->context;
661 int status = urb->status;
662 int retval;
663 unsigned long flags;
664
665 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
666 urb->actual_length, urb->transfer_buffer);
667
668 if (status) {
669 if (status == -ENOENT ||
670 status == -ECONNRESET ||
671 status == -ESHUTDOWN) {
672 goto exit;
673 } else {
674 dev_dbg(&dev->udev->dev,
675 "%s: nonzero status received: %d\n", __func__,
676 status);
677 goto resubmit; /* maybe we can recover */
678 }
679 }
680
681 if (urb->actual_length > 0) {
682 spin_lock_irqsave(&dev->read_buffer_lock, flags);
683 if (dev->read_buffer_length + urb->actual_length < read_buffer_size) {
684 memcpy(dev->read_buffer + dev->read_buffer_length,
685 dev->interrupt_in_buffer,
686 urb->actual_length);
687 dev->read_buffer_length += urb->actual_length;
688 dev->read_last_arrival = jiffies;
689 dev_dbg(&dev->udev->dev, "%s: received %d bytes\n",
690 __func__, urb->actual_length);
691 } else {
692 pr_warn("read_buffer overflow, %d bytes dropped\n",
693 urb->actual_length);
694 }
695 spin_unlock_irqrestore(&dev->read_buffer_lock, flags);
696 }
697
698resubmit:
699 retval = usb_submit_urb(dev->interrupt_in_urb, GFP_ATOMIC);
700 if (retval) {
701 dev_err(&dev->udev->dev, "%s: usb_submit_urb failed (%d)\n",
702 __func__, retval);
703 }
704exit:
705 dev->interrupt_in_done = 1;
706 wake_up_interruptible(&dev->read_wait);
707}
708
709
710/*
711 * tower_interrupt_out_callback
712 */
713static void tower_interrupt_out_callback(struct urb *urb)
714{
715 struct lego_usb_tower *dev = urb->context;
716 int status = urb->status;
717
718 lego_usb_tower_debug_data(&dev->udev->dev, __func__,
719 urb->actual_length, urb->transfer_buffer);
720
721 /* sync/async unlink faults aren't errors */
722 if (status && !(status == -ENOENT ||
723 status == -ECONNRESET ||
724 status == -ESHUTDOWN)) {
725 dev_dbg(&dev->udev->dev,
726 "%s: nonzero write bulk status received: %d\n", __func__,
727 status);
728 }
729
730 dev->interrupt_out_busy = 0;
731 wake_up_interruptible(&dev->write_wait);
732}
733
734
735/*
736 * tower_probe
737 *
738 * Called by the usb core when a new device is connected that it thinks
739 * this driver might be interested in.
740 */
741static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id)
742{
743 struct device *idev = &interface->dev;
744 struct usb_device *udev = interface_to_usbdev(interface);
745 struct lego_usb_tower *dev;
746 struct tower_get_version_reply get_version_reply;
747 int retval = -ENOMEM;
748 int result;
749
750 /* allocate memory for our device state and initialize it */
751 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
752 if (!dev)
753 goto exit;
754
755 mutex_init(&dev->lock);
756 dev->udev = usb_get_dev(udev);
757 spin_lock_init(&dev->read_buffer_lock);
758 dev->packet_timeout_jiffies = msecs_to_jiffies(packet_timeout);
759 dev->read_last_arrival = jiffies;
760 init_waitqueue_head(&dev->read_wait);
761 init_waitqueue_head(&dev->write_wait);
762
763 result = usb_find_common_endpoints_reverse(interface->cur_altsetting,
764 NULL, NULL,
765 &dev->interrupt_in_endpoint,
766 &dev->interrupt_out_endpoint);
767 if (result) {
768 dev_err(idev, "interrupt endpoints not found\n");
769 retval = result;
770 goto error;
771 }
772
773 dev->read_buffer = kmalloc(read_buffer_size, GFP_KERNEL);
774 if (!dev->read_buffer)
775 goto error;
776 dev->interrupt_in_buffer = kmalloc(usb_endpoint_maxp(dev->interrupt_in_endpoint), GFP_KERNEL);
777 if (!dev->interrupt_in_buffer)
778 goto error;
779 dev->interrupt_in_urb = usb_alloc_urb(0, GFP_KERNEL);
780 if (!dev->interrupt_in_urb)
781 goto error;
782 dev->interrupt_out_buffer = kmalloc(write_buffer_size, GFP_KERNEL);
783 if (!dev->interrupt_out_buffer)
784 goto error;
785 dev->interrupt_out_urb = usb_alloc_urb(0, GFP_KERNEL);
786 if (!dev->interrupt_out_urb)
787 goto error;
788 dev->interrupt_in_interval = interrupt_in_interval ? interrupt_in_interval : dev->interrupt_in_endpoint->bInterval;
789 dev->interrupt_out_interval = interrupt_out_interval ? interrupt_out_interval : dev->interrupt_out_endpoint->bInterval;
790
791 /* get the firmware version and log it */
792 result = usb_control_msg_recv(udev, 0,
793 LEGO_USB_TOWER_REQUEST_GET_VERSION,
794 USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE,
795 0,
796 0,
797 &get_version_reply,
798 sizeof(get_version_reply),
799 1000, GFP_KERNEL);
800 if (result) {
801 dev_err(idev, "get version request failed: %d\n", result);
802 retval = result;
803 goto error;
804 }
805 dev_info(&interface->dev,
806 "LEGO USB Tower firmware version is %d.%d build %d\n",
807 get_version_reply.major,
808 get_version_reply.minor,
809 le16_to_cpu(get_version_reply.build_no));
810
811 /* we can register the device now, as it is ready */
812 usb_set_intfdata(interface, dev);
813
814 retval = usb_register_dev(interface, &tower_class);
815 if (retval) {
816 /* something prevented us from registering this driver */
817 dev_err(idev, "Not able to get a minor for this device.\n");
818 goto error;
819 }
820 dev->minor = interface->minor;
821
822 /* let the user know what node this device is now attached to */
823 dev_info(&interface->dev, "LEGO USB Tower #%d now attached to major "
824 "%d minor %d\n", (dev->minor - LEGO_USB_TOWER_MINOR_BASE),
825 USB_MAJOR, dev->minor);
826
827exit:
828 return retval;
829
830error:
831 tower_delete(dev);
832 return retval;
833}
834
835
836/*
837 * tower_disconnect
838 *
839 * Called by the usb core when the device is removed from the system.
840 */
841static void tower_disconnect(struct usb_interface *interface)
842{
843 struct lego_usb_tower *dev;
844 int minor;
845
846 dev = usb_get_intfdata(interface);
847
848 minor = dev->minor;
849
850 /* give back our minor and prevent further open() */
851 usb_deregister_dev(interface, &tower_class);
852
853 /* stop I/O */
854 usb_poison_urb(dev->interrupt_in_urb);
855 usb_poison_urb(dev->interrupt_out_urb);
856
857 mutex_lock(&dev->lock);
858
859 /* if the device is not opened, then we clean up right now */
860 if (!dev->open_count) {
861 mutex_unlock(&dev->lock);
862 tower_delete(dev);
863 } else {
864 dev->disconnected = 1;
865 /* wake up pollers */
866 wake_up_interruptible_all(&dev->read_wait);
867 wake_up_interruptible_all(&dev->write_wait);
868 mutex_unlock(&dev->lock);
869 }
870
871 dev_info(&interface->dev, "LEGO USB Tower #%d now disconnected\n",
872 (minor - LEGO_USB_TOWER_MINOR_BASE));
873}
874
875module_usb_driver(tower_driver);
876
877MODULE_AUTHOR(DRIVER_AUTHOR);
878MODULE_DESCRIPTION(DRIVER_DESC);
879MODULE_LICENSE("GPL");