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 | */ |
98 | static int read_buffer_size = 480; |
99 | module_param(read_buffer_size, int, 0); |
100 | MODULE_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 | */ |
108 | static int write_buffer_size = 480; |
109 | module_param(write_buffer_size, int, 0); |
110 | MODULE_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 | */ |
122 | static int packet_timeout = 50; |
123 | module_param(packet_timeout, int, 0); |
124 | MODULE_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 | */ |
130 | static int read_timeout = 200; |
131 | module_param(read_timeout, int, 0); |
132 | MODULE_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 | */ |
143 | static int interrupt_in_interval = 2; |
144 | module_param(interrupt_in_interval, int, 0); |
145 | MODULE_PARM_DESC(interrupt_in_interval, "Interrupt in interval in ms" ); |
146 | |
147 | static int interrupt_out_interval = 8; |
148 | module_param(interrupt_out_interval, int, 0); |
149 | MODULE_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 | |
159 | struct tower_reset_reply { |
160 | __le16 size; |
161 | __u8 err_code; |
162 | __u8 spare; |
163 | }; |
164 | |
165 | struct 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 */ |
176 | static 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 | |
181 | MODULE_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 */ |
187 | struct 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 */ |
221 | static ssize_t tower_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos); |
222 | static ssize_t tower_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos); |
223 | static inline void tower_delete(struct lego_usb_tower *dev); |
224 | static int tower_open(struct inode *inode, struct file *file); |
225 | static int tower_release(struct inode *inode, struct file *file); |
226 | static __poll_t tower_poll(struct file *file, poll_table *wait); |
227 | static loff_t tower_llseek(struct file *file, loff_t off, int whence); |
228 | |
229 | static void tower_check_for_read_packet(struct lego_usb_tower *dev); |
230 | static void tower_interrupt_in_callback(struct urb *urb); |
231 | static void tower_interrupt_out_callback(struct urb *urb); |
232 | |
233 | static int tower_probe(struct usb_interface *interface, const struct usb_device_id *id); |
234 | static void tower_disconnect(struct usb_interface *interface); |
235 | |
236 | |
237 | /* file operations needed when we register this driver */ |
238 | static 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 | |
248 | static char *legousbtower_devnode(const struct device *dev, umode_t *mode) |
249 | { |
250 | return kasprintf(GFP_KERNEL, fmt: "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 | */ |
257 | static 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 */ |
266 | static 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 | */ |
277 | static 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 | */ |
289 | static inline void tower_delete(struct lego_usb_tower *dev) |
290 | { |
291 | /* free data structures */ |
292 | usb_free_urb(urb: dev->interrupt_in_urb); |
293 | usb_free_urb(urb: dev->interrupt_out_urb); |
294 | kfree(objp: dev->read_buffer); |
295 | kfree(objp: dev->interrupt_in_buffer); |
296 | kfree(objp: dev->interrupt_out_buffer); |
297 | usb_put_dev(dev: dev->udev); |
298 | kfree(objp: dev); |
299 | } |
300 | |
301 | |
302 | /* |
303 | * tower_open |
304 | */ |
305 | static 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, filp: file); |
315 | subminor = iminor(inode); |
316 | |
317 | interface = usb_find_interface(drv: &tower_driver, minor: 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(intf: 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: dev->udev, endpoint: 0, |
345 | LEGO_USB_TOWER_REQUEST_RESET, |
346 | USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE, |
347 | value: 0, index: 0, |
348 | data: &reset_reply, size: sizeof(reset_reply), timeout: 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(urb: dev->interrupt_in_urb, |
361 | dev: dev->udev, |
362 | usb_rcvintpipe(dev->udev, dev->interrupt_in_endpoint->bEndpointAddress), |
363 | transfer_buffer: dev->interrupt_in_buffer, |
364 | buffer_length: usb_endpoint_maxp(epd: dev->interrupt_in_endpoint), |
365 | complete_fn: tower_interrupt_in_callback, |
366 | context: dev, |
367 | interval: dev->interrupt_in_interval); |
368 | |
369 | dev->interrupt_in_done = 0; |
370 | mb(); |
371 | |
372 | retval = usb_submit_urb(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 | |
384 | unlock_exit: |
385 | mutex_unlock(lock: &dev->lock); |
386 | |
387 | exit: |
388 | return retval; |
389 | } |
390 | |
391 | /* |
392 | * tower_release |
393 | */ |
394 | static 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(lock: &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(urb: dev->interrupt_in_urb); |
424 | usb_kill_urb(urb: dev->interrupt_out_urb); |
425 | |
426 | dev->open_count = 0; |
427 | |
428 | mutex_unlock(lock: &dev->lock); |
429 | exit: |
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 | */ |
441 | static void tower_check_for_read_packet(struct lego_usb_tower *dev) |
442 | { |
443 | spin_lock_irq(lock: &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(lock: &dev->read_buffer_lock); |
451 | } |
452 | |
453 | |
454 | /* |
455 | * tower_poll |
456 | */ |
457 | static __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(filp: file, wait_address: &dev->read_wait, p: wait); |
468 | poll_wait(filp: file, wait_address: &dev->write_wait, p: 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 | */ |
483 | static 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 | */ |
492 | static 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(m: 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(m: 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(to: buffer, from: dev->read_buffer, n: bytes_to_read)) { |
551 | retval = -EFAULT; |
552 | goto unlock_exit; |
553 | } |
554 | |
555 | spin_lock_irq(lock: &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(lock: &dev->read_buffer_lock); |
561 | |
562 | retval = bytes_to_read; |
563 | |
564 | unlock_exit: |
565 | /* unlock the device */ |
566 | mutex_unlock(lock: &dev->lock); |
567 | |
568 | exit: |
569 | return retval; |
570 | } |
571 | |
572 | |
573 | /* |
574 | * tower_write |
575 | */ |
576 | static 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(to: dev->interrupt_out_buffer, from: buffer, n: bytes_to_write)) { |
620 | retval = -EFAULT; |
621 | goto unlock_exit; |
622 | } |
623 | |
624 | /* send off the urb */ |
625 | usb_fill_int_urb(urb: dev->interrupt_out_urb, |
626 | dev: dev->udev, |
627 | usb_sndintpipe(dev->udev, dev->interrupt_out_endpoint->bEndpointAddress), |
628 | transfer_buffer: dev->interrupt_out_buffer, |
629 | buffer_length: bytes_to_write, |
630 | complete_fn: tower_interrupt_out_callback, |
631 | context: dev, |
632 | interval: dev->interrupt_out_interval); |
633 | |
634 | dev->interrupt_out_busy = 1; |
635 | wmb(); |
636 | |
637 | retval = usb_submit_urb(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 | |
646 | unlock_exit: |
647 | /* unlock the device */ |
648 | mutex_unlock(lock: &dev->lock); |
649 | |
650 | exit: |
651 | return retval; |
652 | } |
653 | |
654 | |
655 | /* |
656 | * tower_interrupt_in_callback |
657 | */ |
658 | static 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: &dev->udev->dev, function: __func__, |
666 | size: urb->actual_length, data: 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(lock: &dev->read_buffer_lock, flags); |
696 | } |
697 | |
698 | resubmit: |
699 | retval = usb_submit_urb(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 | } |
704 | exit: |
705 | dev->interrupt_in_done = 1; |
706 | wake_up_interruptible(&dev->read_wait); |
707 | } |
708 | |
709 | |
710 | /* |
711 | * tower_interrupt_out_callback |
712 | */ |
713 | static 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: &dev->udev->dev, function: __func__, |
719 | size: urb->actual_length, data: 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 | */ |
741 | static 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(size: sizeof(*dev), GFP_KERNEL); |
752 | if (!dev) |
753 | goto exit; |
754 | |
755 | mutex_init(&dev->lock); |
756 | dev->udev = usb_get_dev(dev: udev); |
757 | spin_lock_init(&dev->read_buffer_lock); |
758 | dev->packet_timeout_jiffies = msecs_to_jiffies(m: 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(alt: interface->cur_altsetting, |
764 | NULL, NULL, |
765 | int_in: &dev->interrupt_in_endpoint, |
766 | int_out: &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(size: read_buffer_size, GFP_KERNEL); |
774 | if (!dev->read_buffer) |
775 | goto error; |
776 | dev->interrupt_in_buffer = kmalloc(size: usb_endpoint_maxp(epd: dev->interrupt_in_endpoint), GFP_KERNEL); |
777 | if (!dev->interrupt_in_buffer) |
778 | goto error; |
779 | dev->interrupt_in_urb = usb_alloc_urb(iso_packets: 0, GFP_KERNEL); |
780 | if (!dev->interrupt_in_urb) |
781 | goto error; |
782 | dev->interrupt_out_buffer = kmalloc(size: write_buffer_size, GFP_KERNEL); |
783 | if (!dev->interrupt_out_buffer) |
784 | goto error; |
785 | dev->interrupt_out_urb = usb_alloc_urb(iso_packets: 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(dev: udev, endpoint: 0, |
793 | LEGO_USB_TOWER_REQUEST_GET_VERSION, |
794 | USB_TYPE_VENDOR | USB_DIR_IN | USB_RECIP_DEVICE, |
795 | value: 0, |
796 | index: 0, |
797 | data: &get_version_reply, |
798 | size: sizeof(get_version_reply), |
799 | timeout: 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(intf: interface, data: dev); |
813 | |
814 | retval = usb_register_dev(intf: interface, class_driver: &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 | |
827 | exit: |
828 | return retval; |
829 | |
830 | error: |
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 | */ |
841 | static void tower_disconnect(struct usb_interface *interface) |
842 | { |
843 | struct lego_usb_tower *dev; |
844 | int minor; |
845 | |
846 | dev = usb_get_intfdata(intf: interface); |
847 | |
848 | minor = dev->minor; |
849 | |
850 | /* give back our minor and prevent further open() */ |
851 | usb_deregister_dev(intf: interface, class_driver: &tower_class); |
852 | |
853 | /* stop I/O */ |
854 | usb_poison_urb(urb: dev->interrupt_in_urb); |
855 | usb_poison_urb(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(lock: &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(lock: &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 | |
875 | module_usb_driver(tower_driver); |
876 | |
877 | MODULE_AUTHOR(DRIVER_AUTHOR); |
878 | MODULE_DESCRIPTION(DRIVER_DESC); |
879 | MODULE_LICENSE("GPL" ); |
880 | |