blob: f6e80c7ca61e53c0f9655778306ffc3e82a28b9f [file] [log] [blame]
Stefan Achatz206f5f22010-05-19 18:55:16 +02001/*
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
36struct roccat_report {
37 uint8_t *value;
38 int len;
39};
40
41struct 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
61struct roccat_reader {
62 struct list_head node;
63 struct roccat_device *device;
64 int cbuf_start;
65};
66
67static int roccat_major;
68static struct class *roccat_class;
69static struct cdev roccat_cdev;
70
71static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
72/* protects modifications of devices array */
73static DEFINE_MUTEX(devices_lock);
74
75static 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
134exit_unlock:
135 mutex_unlock(&device->cbuf_lock);
136 return retval;
137}
138
139static 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
150static 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;
Julia Lawalldfe5c7b2010-06-01 16:35:15 +0200171 goto exit_err;
Stefan Achatz206f5f22010-05-19 18:55:16 +0200172 }
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;
Julia Lawalldfe5c7b2010-06-01 16:35:15 +0200181 goto exit_err;
Stefan Achatz206f5f22010-05-19 18:55:16 +0200182 }
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;
Julia Lawalldfe5c7b2010-06-01 16:35:15 +0200190 goto exit_err;
Stefan Achatz206f5f22010-05-19 18:55:16 +0200191 }
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
201exit_unlock:
202 mutex_unlock(&device->readers_lock);
203 mutex_unlock(&devices_lock);
204 return error;
Julia Lawalldfe5c7b2010-06-01 16:35:15 +0200205exit_err:
206 kfree(reader);
207 goto exit_unlock;
Stefan Achatz206f5f22010-05-19 18:55:16 +0200208}
209
210static 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 */
258int 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}
294EXPORT_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 */
303int 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}
354EXPORT_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 */
359void 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}
379EXPORT_SYMBOL_GPL(roccat_disconnect);
380
381static 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
389static 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
417static 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
426module_init(roccat_init);
427module_exit(roccat_exit);
428
429MODULE_AUTHOR("Stefan Achatz");
430MODULE_DESCRIPTION("USB Roccat char device");
431MODULE_LICENSE("GPL v2");