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206f5f2f SA |
1 | /* |
2 | * Roccat driver for Linux | |
3 | * | |
4 | * Copyright (c) 2010 Stefan Achatz <erazor_de@users.sourceforge.net> | |
5 | */ | |
6 | ||
7 | /* | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License as published by the Free | |
10 | * Software Foundation; either version 2 of the License, or (at your option) | |
11 | * any later version. | |
12 | */ | |
13 | ||
14 | /* | |
15 | * Module roccat is a char device used to report special events of roccat | |
16 | * hardware to userland. These events include requests for on-screen-display of | |
17 | * profile or dpi settings or requests for execution of macro sequences that are | |
18 | * not stored in device. The information in these events depends on hid device | |
19 | * implementation and contains data that is not available in a single hid event | |
20 | * or else hidraw could have been used. | |
21 | * It is inspired by hidraw, but uses only one circular buffer for all readers. | |
22 | */ | |
23 | ||
24 | #include <linux/cdev.h> | |
25 | #include <linux/poll.h> | |
26 | #include <linux/sched.h> | |
27 | ||
28 | #include "hid-roccat.h" | |
29 | ||
30 | #define ROCCAT_FIRST_MINOR 0 | |
31 | #define ROCCAT_MAX_DEVICES 8 | |
32 | ||
33 | /* should be a power of 2 for performance reason */ | |
34 | #define ROCCAT_CBUF_SIZE 16 | |
35 | ||
36 | struct roccat_report { | |
37 | uint8_t *value; | |
38 | int len; | |
39 | }; | |
40 | ||
41 | struct roccat_device { | |
42 | unsigned int minor; | |
43 | int open; | |
44 | int exist; | |
45 | wait_queue_head_t wait; | |
46 | struct device *dev; | |
47 | struct hid_device *hid; | |
48 | struct list_head readers; | |
49 | /* protects modifications of readers list */ | |
50 | struct mutex readers_lock; | |
51 | ||
52 | /* | |
53 | * circular_buffer has one writer and multiple readers with their own | |
54 | * read pointers | |
55 | */ | |
56 | struct roccat_report cbuf[ROCCAT_CBUF_SIZE]; | |
57 | int cbuf_end; | |
58 | struct mutex cbuf_lock; | |
59 | }; | |
60 | ||
61 | struct roccat_reader { | |
62 | struct list_head node; | |
63 | struct roccat_device *device; | |
64 | int cbuf_start; | |
65 | }; | |
66 | ||
67 | static int roccat_major; | |
68 | static struct class *roccat_class; | |
69 | static struct cdev roccat_cdev; | |
70 | ||
71 | static struct roccat_device *devices[ROCCAT_MAX_DEVICES]; | |
72 | /* protects modifications of devices array */ | |
73 | static DEFINE_MUTEX(devices_lock); | |
74 | ||
75 | static ssize_t roccat_read(struct file *file, char __user *buffer, | |
76 | size_t count, loff_t *ppos) | |
77 | { | |
78 | struct roccat_reader *reader = file->private_data; | |
79 | struct roccat_device *device = reader->device; | |
80 | struct roccat_report *report; | |
81 | ssize_t retval = 0, len; | |
82 | DECLARE_WAITQUEUE(wait, current); | |
83 | ||
84 | mutex_lock(&device->cbuf_lock); | |
85 | ||
86 | /* no data? */ | |
87 | if (reader->cbuf_start == device->cbuf_end) { | |
88 | add_wait_queue(&device->wait, &wait); | |
89 | set_current_state(TASK_INTERRUPTIBLE); | |
90 | ||
91 | /* wait for data */ | |
92 | while (reader->cbuf_start == device->cbuf_end) { | |
93 | if (file->f_flags & O_NONBLOCK) { | |
94 | retval = -EAGAIN; | |
95 | break; | |
96 | } | |
97 | if (signal_pending(current)) { | |
98 | retval = -ERESTARTSYS; | |
99 | break; | |
100 | } | |
101 | if (!device->exist) { | |
102 | retval = -EIO; | |
103 | break; | |
104 | } | |
105 | ||
106 | mutex_unlock(&device->cbuf_lock); | |
107 | schedule(); | |
108 | mutex_lock(&device->cbuf_lock); | |
109 | set_current_state(TASK_INTERRUPTIBLE); | |
110 | } | |
111 | ||
112 | set_current_state(TASK_RUNNING); | |
113 | remove_wait_queue(&device->wait, &wait); | |
114 | } | |
115 | ||
116 | /* here we either have data or a reason to return if retval is set */ | |
117 | if (retval) | |
118 | goto exit_unlock; | |
119 | ||
120 | report = &device->cbuf[reader->cbuf_start]; | |
121 | /* | |
122 | * If report is larger than requested amount of data, rest of report | |
123 | * is lost! | |
124 | */ | |
125 | len = report->len > count ? count : report->len; | |
126 | ||
127 | if (copy_to_user(buffer, report->value, len)) { | |
128 | retval = -EFAULT; | |
129 | goto exit_unlock; | |
130 | } | |
131 | retval += len; | |
132 | reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE; | |
133 | ||
134 | exit_unlock: | |
135 | mutex_unlock(&device->cbuf_lock); | |
136 | return retval; | |
137 | } | |
138 | ||
139 | static unsigned int roccat_poll(struct file *file, poll_table *wait) | |
140 | { | |
141 | struct roccat_reader *reader = file->private_data; | |
142 | poll_wait(file, &reader->device->wait, wait); | |
143 | if (reader->cbuf_start != reader->device->cbuf_end) | |
144 | return POLLIN | POLLRDNORM; | |
145 | if (!reader->device->exist) | |
146 | return POLLERR | POLLHUP; | |
147 | return 0; | |
148 | } | |
149 | ||
150 | static int roccat_open(struct inode *inode, struct file *file) | |
151 | { | |
152 | unsigned int minor = iminor(inode); | |
153 | struct roccat_reader *reader; | |
154 | struct roccat_device *device; | |
155 | int error = 0; | |
156 | ||
157 | reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL); | |
158 | if (!reader) | |
159 | return -ENOMEM; | |
160 | ||
161 | mutex_lock(&devices_lock); | |
162 | ||
163 | device = devices[minor]; | |
164 | ||
165 | mutex_lock(&device->readers_lock); | |
166 | ||
167 | if (!device) { | |
168 | printk(KERN_EMERG "roccat device with minor %d doesn't exist\n", | |
169 | minor); | |
170 | error = -ENODEV; | |
dfe5c7b7 | 171 | goto exit_err; |
206f5f2f SA |
172 | } |
173 | ||
174 | if (!device->open++) { | |
175 | /* power on device on adding first reader */ | |
176 | if (device->hid->ll_driver->power) { | |
177 | error = device->hid->ll_driver->power(device->hid, | |
178 | PM_HINT_FULLON); | |
179 | if (error < 0) { | |
180 | --device->open; | |
dfe5c7b7 | 181 | goto exit_err; |
206f5f2f SA |
182 | } |
183 | } | |
184 | error = device->hid->ll_driver->open(device->hid); | |
185 | if (error < 0) { | |
186 | if (device->hid->ll_driver->power) | |
187 | device->hid->ll_driver->power(device->hid, | |
188 | PM_HINT_NORMAL); | |
189 | --device->open; | |
dfe5c7b7 | 190 | goto exit_err; |
206f5f2f SA |
191 | } |
192 | } | |
193 | ||
194 | reader->device = device; | |
195 | /* new reader doesn't get old events */ | |
196 | reader->cbuf_start = device->cbuf_end; | |
197 | ||
198 | list_add_tail(&reader->node, &device->readers); | |
199 | file->private_data = reader; | |
200 | ||
201 | exit_unlock: | |
202 | mutex_unlock(&device->readers_lock); | |
203 | mutex_unlock(&devices_lock); | |
204 | return error; | |
dfe5c7b7 JL |
205 | exit_err: |
206 | kfree(reader); | |
207 | goto exit_unlock; | |
206f5f2f SA |
208 | } |
209 | ||
210 | static int roccat_release(struct inode *inode, struct file *file) | |
211 | { | |
212 | unsigned int minor = iminor(inode); | |
213 | struct roccat_reader *reader = file->private_data; | |
214 | struct roccat_device *device; | |
215 | ||
216 | mutex_lock(&devices_lock); | |
217 | ||
218 | device = devices[minor]; | |
219 | if (!device) { | |
220 | mutex_unlock(&devices_lock); | |
221 | printk(KERN_EMERG "roccat device with minor %d doesn't exist\n", | |
222 | minor); | |
223 | return -ENODEV; | |
224 | } | |
225 | ||
226 | mutex_lock(&device->readers_lock); | |
227 | list_del(&reader->node); | |
228 | mutex_unlock(&device->readers_lock); | |
229 | kfree(reader); | |
230 | ||
231 | if (!--device->open) { | |
232 | /* removing last reader */ | |
233 | if (device->exist) { | |
234 | if (device->hid->ll_driver->power) | |
235 | device->hid->ll_driver->power(device->hid, | |
236 | PM_HINT_NORMAL); | |
237 | device->hid->ll_driver->close(device->hid); | |
238 | } else { | |
239 | kfree(device); | |
240 | } | |
241 | } | |
242 | ||
243 | mutex_unlock(&devices_lock); | |
244 | ||
245 | return 0; | |
246 | } | |
247 | ||
248 | /* | |
249 | * roccat_report_event() - output data to readers | |
250 | * @minor: minor device number returned by roccat_connect() | |
251 | * @data: pointer to data | |
252 | * @len: size of data | |
253 | * | |
254 | * Return value is zero on success, a negative error code on failure. | |
255 | * | |
256 | * This is called from interrupt handler. | |
257 | */ | |
258 | int roccat_report_event(int minor, u8 const *data, int len) | |
259 | { | |
260 | struct roccat_device *device; | |
261 | struct roccat_reader *reader; | |
262 | struct roccat_report *report; | |
263 | uint8_t *new_value; | |
264 | ||
265 | new_value = kmemdup(data, len, GFP_ATOMIC); | |
266 | if (!new_value) | |
267 | return -ENOMEM; | |
268 | ||
269 | device = devices[minor]; | |
270 | ||
271 | report = &device->cbuf[device->cbuf_end]; | |
272 | ||
273 | /* passing NULL is safe */ | |
274 | kfree(report->value); | |
275 | ||
276 | report->value = new_value; | |
277 | report->len = len; | |
278 | device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE; | |
279 | ||
280 | list_for_each_entry(reader, &device->readers, node) { | |
281 | /* | |
282 | * As we already inserted one element, the buffer can't be | |
283 | * empty. If start and end are equal, buffer is full and we | |
284 | * increase start, so that slow reader misses one event, but | |
285 | * gets the newer ones in the right order. | |
286 | */ | |
287 | if (reader->cbuf_start == device->cbuf_end) | |
288 | reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE; | |
289 | } | |
290 | ||
291 | wake_up_interruptible(&device->wait); | |
292 | return 0; | |
293 | } | |
294 | EXPORT_SYMBOL_GPL(roccat_report_event); | |
295 | ||
296 | /* | |
297 | * roccat_connect() - create a char device for special event output | |
298 | * @hid: the hid device the char device should be connected to. | |
299 | * | |
300 | * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on | |
301 | * success, a negative error code on failure. | |
302 | */ | |
303 | int roccat_connect(struct hid_device *hid) | |
304 | { | |
305 | unsigned int minor; | |
306 | struct roccat_device *device; | |
307 | int temp; | |
308 | ||
309 | device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL); | |
310 | if (!device) | |
311 | return -ENOMEM; | |
312 | ||
313 | mutex_lock(&devices_lock); | |
314 | ||
315 | for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) { | |
316 | if (devices[minor]) | |
317 | continue; | |
318 | break; | |
319 | } | |
320 | ||
321 | if (minor < ROCCAT_MAX_DEVICES) { | |
322 | devices[minor] = device; | |
323 | } else { | |
324 | mutex_unlock(&devices_lock); | |
325 | kfree(device); | |
326 | return -EINVAL; | |
327 | } | |
328 | ||
329 | device->dev = device_create(roccat_class, &hid->dev, | |
330 | MKDEV(roccat_major, minor), NULL, | |
331 | "%s%s%d", "roccat", hid->driver->name, minor); | |
332 | ||
333 | if (IS_ERR(device->dev)) { | |
334 | devices[minor] = NULL; | |
335 | mutex_unlock(&devices_lock); | |
336 | temp = PTR_ERR(device->dev); | |
337 | kfree(device); | |
338 | return temp; | |
339 | } | |
340 | ||
341 | mutex_unlock(&devices_lock); | |
342 | ||
343 | init_waitqueue_head(&device->wait); | |
344 | INIT_LIST_HEAD(&device->readers); | |
345 | mutex_init(&device->readers_lock); | |
346 | mutex_init(&device->cbuf_lock); | |
347 | device->minor = minor; | |
348 | device->hid = hid; | |
349 | device->exist = 1; | |
350 | device->cbuf_end = 0; | |
351 | ||
352 | return minor; | |
353 | } | |
354 | EXPORT_SYMBOL_GPL(roccat_connect); | |
355 | ||
356 | /* roccat_disconnect() - remove char device from hid device | |
357 | * @minor: the minor device number returned by roccat_connect() | |
358 | */ | |
359 | void roccat_disconnect(int minor) | |
360 | { | |
361 | struct roccat_device *device; | |
362 | ||
363 | mutex_lock(&devices_lock); | |
364 | device = devices[minor]; | |
365 | devices[minor] = NULL; | |
366 | mutex_unlock(&devices_lock); | |
367 | ||
368 | device->exist = 0; /* TODO exist maybe not needed */ | |
369 | ||
370 | device_destroy(roccat_class, MKDEV(roccat_major, minor)); | |
371 | ||
372 | if (device->open) { | |
373 | device->hid->ll_driver->close(device->hid); | |
374 | wake_up_interruptible(&device->wait); | |
375 | } else { | |
376 | kfree(device); | |
377 | } | |
378 | } | |
379 | EXPORT_SYMBOL_GPL(roccat_disconnect); | |
380 | ||
381 | static const struct file_operations roccat_ops = { | |
382 | .owner = THIS_MODULE, | |
383 | .read = roccat_read, | |
384 | .poll = roccat_poll, | |
385 | .open = roccat_open, | |
386 | .release = roccat_release, | |
387 | }; | |
388 | ||
389 | static int __init roccat_init(void) | |
390 | { | |
391 | int retval; | |
392 | dev_t dev_id; | |
393 | ||
394 | retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR, | |
395 | ROCCAT_MAX_DEVICES, "roccat"); | |
396 | ||
397 | roccat_major = MAJOR(dev_id); | |
398 | ||
399 | if (retval < 0) { | |
400 | printk(KERN_WARNING "roccat: can't get major number\n"); | |
401 | return retval; | |
402 | } | |
403 | ||
404 | roccat_class = class_create(THIS_MODULE, "roccat"); | |
405 | if (IS_ERR(roccat_class)) { | |
406 | retval = PTR_ERR(roccat_class); | |
407 | unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); | |
408 | return retval; | |
409 | } | |
410 | ||
411 | cdev_init(&roccat_cdev, &roccat_ops); | |
412 | cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); | |
413 | ||
414 | return 0; | |
415 | } | |
416 | ||
417 | static void __exit roccat_exit(void) | |
418 | { | |
419 | dev_t dev_id = MKDEV(roccat_major, 0); | |
420 | ||
421 | cdev_del(&roccat_cdev); | |
422 | class_destroy(roccat_class); | |
423 | unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); | |
424 | } | |
425 | ||
426 | module_init(roccat_init); | |
427 | module_exit(roccat_exit); | |
428 | ||
429 | MODULE_AUTHOR("Stefan Achatz"); | |
430 | MODULE_DESCRIPTION("USB Roccat char device"); | |
431 | MODULE_LICENSE("GPL v2"); |