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; 171 goto exit_err; 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; 181 goto exit_err; 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; 190 goto exit_err; 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; 205 exit_err: 206 kfree(reader); 207 goto exit_unlock; 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 .llseek = noop_llseek, 388 }; 389 390 static int __init roccat_init(void) 391 { 392 int retval; 393 dev_t dev_id; 394 395 retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR, 396 ROCCAT_MAX_DEVICES, "roccat"); 397 398 roccat_major = MAJOR(dev_id); 399 400 if (retval < 0) { 401 printk(KERN_WARNING "roccat: can't get major number\n"); 402 return retval; 403 } 404 405 roccat_class = class_create(THIS_MODULE, "roccat"); 406 if (IS_ERR(roccat_class)) { 407 retval = PTR_ERR(roccat_class); 408 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 409 return retval; 410 } 411 412 cdev_init(&roccat_cdev, &roccat_ops); 413 cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); 414 415 return 0; 416 } 417 418 static void __exit roccat_exit(void) 419 { 420 dev_t dev_id = MKDEV(roccat_major, 0); 421 422 cdev_del(&roccat_cdev); 423 class_destroy(roccat_class); 424 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 425 } 426 427 module_init(roccat_init); 428 module_exit(roccat_exit); 429 430 MODULE_AUTHOR("Stefan Achatz"); 431 MODULE_DESCRIPTION("USB Roccat char device"); 432 MODULE_LICENSE("GPL v2"); 433