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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
Joe Perches4291ee32010-12-09 19:29:03 -080024#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
25
Stefan Achatz206f5f22010-05-19 18:55:16 +020026#include <linux/cdev.h>
27#include <linux/poll.h>
28#include <linux/sched.h>
29
30#include "hid-roccat.h"
31
32#define ROCCAT_FIRST_MINOR 0
33#define ROCCAT_MAX_DEVICES 8
34
35/* should be a power of 2 for performance reason */
36#define ROCCAT_CBUF_SIZE 16
37
38struct roccat_report {
39 uint8_t *value;
40 int len;
41};
42
43struct roccat_device {
44 unsigned int minor;
45 int open;
46 int exist;
47 wait_queue_head_t wait;
48 struct device *dev;
49 struct hid_device *hid;
50 struct list_head readers;
51 /* protects modifications of readers list */
52 struct mutex readers_lock;
53
54 /*
55 * circular_buffer has one writer and multiple readers with their own
56 * read pointers
57 */
58 struct roccat_report cbuf[ROCCAT_CBUF_SIZE];
59 int cbuf_end;
60 struct mutex cbuf_lock;
61};
62
63struct roccat_reader {
64 struct list_head node;
65 struct roccat_device *device;
66 int cbuf_start;
67};
68
69static int roccat_major;
Stefan Achatz206f5f22010-05-19 18:55:16 +020070static struct cdev roccat_cdev;
71
72static struct roccat_device *devices[ROCCAT_MAX_DEVICES];
73/* protects modifications of devices array */
74static DEFINE_MUTEX(devices_lock);
75
76static ssize_t roccat_read(struct file *file, char __user *buffer,
77 size_t count, loff_t *ppos)
78{
79 struct roccat_reader *reader = file->private_data;
80 struct roccat_device *device = reader->device;
81 struct roccat_report *report;
82 ssize_t retval = 0, len;
83 DECLARE_WAITQUEUE(wait, current);
84
85 mutex_lock(&device->cbuf_lock);
86
87 /* no data? */
88 if (reader->cbuf_start == device->cbuf_end) {
89 add_wait_queue(&device->wait, &wait);
90 set_current_state(TASK_INTERRUPTIBLE);
91
92 /* wait for data */
93 while (reader->cbuf_start == device->cbuf_end) {
94 if (file->f_flags & O_NONBLOCK) {
95 retval = -EAGAIN;
96 break;
97 }
98 if (signal_pending(current)) {
99 retval = -ERESTARTSYS;
100 break;
101 }
102 if (!device->exist) {
103 retval = -EIO;
104 break;
105 }
106
107 mutex_unlock(&device->cbuf_lock);
108 schedule();
109 mutex_lock(&device->cbuf_lock);
110 set_current_state(TASK_INTERRUPTIBLE);
111 }
112
113 set_current_state(TASK_RUNNING);
114 remove_wait_queue(&device->wait, &wait);
115 }
116
117 /* here we either have data or a reason to return if retval is set */
118 if (retval)
119 goto exit_unlock;
120
121 report = &device->cbuf[reader->cbuf_start];
122 /*
123 * If report is larger than requested amount of data, rest of report
124 * is lost!
125 */
126 len = report->len > count ? count : report->len;
127
128 if (copy_to_user(buffer, report->value, len)) {
129 retval = -EFAULT;
130 goto exit_unlock;
131 }
132 retval += len;
133 reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
134
135exit_unlock:
136 mutex_unlock(&device->cbuf_lock);
137 return retval;
138}
139
140static unsigned int roccat_poll(struct file *file, poll_table *wait)
141{
142 struct roccat_reader *reader = file->private_data;
143 poll_wait(file, &reader->device->wait, wait);
144 if (reader->cbuf_start != reader->device->cbuf_end)
145 return POLLIN | POLLRDNORM;
146 if (!reader->device->exist)
147 return POLLERR | POLLHUP;
148 return 0;
149}
150
151static int roccat_open(struct inode *inode, struct file *file)
152{
153 unsigned int minor = iminor(inode);
154 struct roccat_reader *reader;
155 struct roccat_device *device;
156 int error = 0;
157
158 reader = kzalloc(sizeof(struct roccat_reader), GFP_KERNEL);
159 if (!reader)
160 return -ENOMEM;
161
162 mutex_lock(&devices_lock);
163
164 device = devices[minor];
165
166 mutex_lock(&device->readers_lock);
167
168 if (!device) {
Joe Perches4291ee32010-12-09 19:29:03 -0800169 pr_emerg("roccat device with minor %d doesn't exist\n", minor);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200170 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 */
Dmitry Torokhov5bea7662010-12-07 23:02:48 -0800176 error = hid_hw_power(device->hid, PM_HINT_FULLON);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200177 if (error < 0) {
Dmitry Torokhov5bea7662010-12-07 23:02:48 -0800178 --device->open;
179 goto exit_err;
180 }
181
182 error = hid_hw_open(device->hid);
183 if (error < 0) {
184 hid_hw_power(device->hid, PM_HINT_NORMAL);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200185 --device->open;
Julia Lawalldfe5c7b2010-06-01 16:35:15 +0200186 goto exit_err;
Stefan Achatz206f5f22010-05-19 18:55:16 +0200187 }
188 }
189
190 reader->device = device;
191 /* new reader doesn't get old events */
192 reader->cbuf_start = device->cbuf_end;
193
194 list_add_tail(&reader->node, &device->readers);
195 file->private_data = reader;
196
197exit_unlock:
198 mutex_unlock(&device->readers_lock);
199 mutex_unlock(&devices_lock);
200 return error;
Julia Lawalldfe5c7b2010-06-01 16:35:15 +0200201exit_err:
202 kfree(reader);
203 goto exit_unlock;
Stefan Achatz206f5f22010-05-19 18:55:16 +0200204}
205
206static int roccat_release(struct inode *inode, struct file *file)
207{
208 unsigned int minor = iminor(inode);
209 struct roccat_reader *reader = file->private_data;
210 struct roccat_device *device;
211
212 mutex_lock(&devices_lock);
213
214 device = devices[minor];
215 if (!device) {
216 mutex_unlock(&devices_lock);
Joe Perches4291ee32010-12-09 19:29:03 -0800217 pr_emerg("roccat device with minor %d doesn't exist\n", minor);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200218 return -ENODEV;
219 }
220
221 mutex_lock(&device->readers_lock);
222 list_del(&reader->node);
223 mutex_unlock(&device->readers_lock);
224 kfree(reader);
225
226 if (!--device->open) {
227 /* removing last reader */
228 if (device->exist) {
Dmitry Torokhov5bea7662010-12-07 23:02:48 -0800229 hid_hw_power(device->hid, PM_HINT_NORMAL);
230 hid_hw_close(device->hid);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200231 } else {
232 kfree(device);
233 }
234 }
235
236 mutex_unlock(&devices_lock);
237
238 return 0;
239}
240
241/*
242 * roccat_report_event() - output data to readers
243 * @minor: minor device number returned by roccat_connect()
244 * @data: pointer to data
245 * @len: size of data
246 *
247 * Return value is zero on success, a negative error code on failure.
248 *
249 * This is called from interrupt handler.
250 */
251int roccat_report_event(int minor, u8 const *data, int len)
252{
253 struct roccat_device *device;
254 struct roccat_reader *reader;
255 struct roccat_report *report;
256 uint8_t *new_value;
257
258 new_value = kmemdup(data, len, GFP_ATOMIC);
259 if (!new_value)
260 return -ENOMEM;
261
262 device = devices[minor];
263
264 report = &device->cbuf[device->cbuf_end];
265
266 /* passing NULL is safe */
267 kfree(report->value);
268
269 report->value = new_value;
270 report->len = len;
271 device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE;
272
273 list_for_each_entry(reader, &device->readers, node) {
274 /*
275 * As we already inserted one element, the buffer can't be
276 * empty. If start and end are equal, buffer is full and we
277 * increase start, so that slow reader misses one event, but
278 * gets the newer ones in the right order.
279 */
280 if (reader->cbuf_start == device->cbuf_end)
281 reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE;
282 }
283
284 wake_up_interruptible(&device->wait);
285 return 0;
286}
287EXPORT_SYMBOL_GPL(roccat_report_event);
288
289/*
290 * roccat_connect() - create a char device for special event output
Stefan Achatz5012aad2010-11-26 19:57:33 +0000291 * @class: the class thats used to create the device. Meant to hold device
292 * specific sysfs attributes.
Stefan Achatz206f5f22010-05-19 18:55:16 +0200293 * @hid: the hid device the char device should be connected to.
294 *
295 * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on
296 * success, a negative error code on failure.
297 */
Stefan Achatz5012aad2010-11-26 19:57:33 +0000298int roccat_connect(struct class *klass, struct hid_device *hid)
Stefan Achatz206f5f22010-05-19 18:55:16 +0200299{
300 unsigned int minor;
301 struct roccat_device *device;
302 int temp;
303
304 device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL);
305 if (!device)
306 return -ENOMEM;
307
308 mutex_lock(&devices_lock);
309
310 for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) {
311 if (devices[minor])
312 continue;
313 break;
314 }
315
316 if (minor < ROCCAT_MAX_DEVICES) {
317 devices[minor] = device;
318 } else {
319 mutex_unlock(&devices_lock);
320 kfree(device);
321 return -EINVAL;
322 }
323
Stefan Achatz5012aad2010-11-26 19:57:33 +0000324 device->dev = device_create(klass, &hid->dev,
Stefan Achatz206f5f22010-05-19 18:55:16 +0200325 MKDEV(roccat_major, minor), NULL,
326 "%s%s%d", "roccat", hid->driver->name, minor);
327
328 if (IS_ERR(device->dev)) {
329 devices[minor] = NULL;
330 mutex_unlock(&devices_lock);
331 temp = PTR_ERR(device->dev);
332 kfree(device);
333 return temp;
334 }
335
336 mutex_unlock(&devices_lock);
337
338 init_waitqueue_head(&device->wait);
339 INIT_LIST_HEAD(&device->readers);
340 mutex_init(&device->readers_lock);
341 mutex_init(&device->cbuf_lock);
342 device->minor = minor;
343 device->hid = hid;
344 device->exist = 1;
345 device->cbuf_end = 0;
346
347 return minor;
348}
349EXPORT_SYMBOL_GPL(roccat_connect);
350
351/* roccat_disconnect() - remove char device from hid device
352 * @minor: the minor device number returned by roccat_connect()
353 */
354void roccat_disconnect(int minor)
355{
356 struct roccat_device *device;
357
358 mutex_lock(&devices_lock);
359 device = devices[minor];
360 devices[minor] = NULL;
361 mutex_unlock(&devices_lock);
362
363 device->exist = 0; /* TODO exist maybe not needed */
364
Stefan Achatz5012aad2010-11-26 19:57:33 +0000365 device_destroy(device->dev->class, MKDEV(roccat_major, minor));
Stefan Achatz206f5f22010-05-19 18:55:16 +0200366
367 if (device->open) {
Dmitry Torokhov5bea7662010-12-07 23:02:48 -0800368 hid_hw_close(device->hid);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200369 wake_up_interruptible(&device->wait);
370 } else {
371 kfree(device);
372 }
373}
374EXPORT_SYMBOL_GPL(roccat_disconnect);
375
376static const struct file_operations roccat_ops = {
377 .owner = THIS_MODULE,
378 .read = roccat_read,
379 .poll = roccat_poll,
380 .open = roccat_open,
381 .release = roccat_release,
Arnd Bergmann6038f372010-08-15 18:52:59 +0200382 .llseek = noop_llseek,
Stefan Achatz206f5f22010-05-19 18:55:16 +0200383};
384
385static int __init roccat_init(void)
386{
387 int retval;
388 dev_t dev_id;
389
390 retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR,
391 ROCCAT_MAX_DEVICES, "roccat");
392
393 roccat_major = MAJOR(dev_id);
394
395 if (retval < 0) {
Joe Perches4291ee32010-12-09 19:29:03 -0800396 pr_warn("can't get major number\n");
Stefan Achatz206f5f22010-05-19 18:55:16 +0200397 return retval;
398 }
399
Stefan Achatz206f5f22010-05-19 18:55:16 +0200400 cdev_init(&roccat_cdev, &roccat_ops);
401 cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES);
402
403 return 0;
404}
405
406static void __exit roccat_exit(void)
407{
408 dev_t dev_id = MKDEV(roccat_major, 0);
409
410 cdev_del(&roccat_cdev);
Stefan Achatz206f5f22010-05-19 18:55:16 +0200411 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES);
412}
413
414module_init(roccat_init);
415module_exit(roccat_exit);
416
417MODULE_AUTHOR("Stefan Achatz");
418MODULE_DESCRIPTION("USB Roccat char device");
419MODULE_LICENSE("GPL v2");