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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 25 26 #include <linux/cdev.h> 27 #include <linux/poll.h> 28 #include <linux/sched/signal.h> 29 #include <linux/hid-roccat.h> 30 #include <linux/module.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 38 struct roccat_report { 39 uint8_t *value; 40 }; 41 42 struct roccat_device { 43 unsigned int minor; 44 int report_size; 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 63 struct roccat_reader { 64 struct list_head node; 65 struct roccat_device *device; 66 int cbuf_start; 67 }; 68 69 static int roccat_major; 70 static struct cdev roccat_cdev; 71 72 static struct roccat_device *devices[ROCCAT_MAX_DEVICES]; 73 /* protects modifications of devices array */ 74 static DEFINE_MUTEX(devices_lock); 75 76 static 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 = device->report_size > count ? count : device->report_size; 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; 134 135 exit_unlock: 136 mutex_unlock(&device->cbuf_lock); 137 return retval; 138 } 139 140 static __poll_t 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 EPOLLIN | EPOLLRDNORM; 146 if (!reader->device->exist) 147 return EPOLLERR | EPOLLHUP; 148 return 0; 149 } 150 151 static 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 if (!device) { 167 pr_emerg("roccat device with minor %d doesn't exist\n", minor); 168 error = -ENODEV; 169 goto exit_err_devices; 170 } 171 172 mutex_lock(&device->readers_lock); 173 174 if (!device->open++) { 175 /* power on device on adding first reader */ 176 error = hid_hw_power(device->hid, PM_HINT_FULLON); 177 if (error < 0) { 178 --device->open; 179 goto exit_err_readers; 180 } 181 182 error = hid_hw_open(device->hid); 183 if (error < 0) { 184 hid_hw_power(device->hid, PM_HINT_NORMAL); 185 --device->open; 186 goto exit_err_readers; 187 } 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; 196 197 exit_err_readers: 198 mutex_unlock(&device->readers_lock); 199 exit_err_devices: 200 mutex_unlock(&devices_lock); 201 if (error) 202 kfree(reader); 203 return error; 204 } 205 206 static 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); 217 pr_emerg("roccat device with minor %d doesn't exist\n", minor); 218 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) { 229 hid_hw_power(device->hid, PM_HINT_NORMAL); 230 hid_hw_close(device->hid); 231 } 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 * 246 * Return value is zero on success, a negative error code on failure. 247 * 248 * This is called from interrupt handler. 249 */ 250 int roccat_report_event(int minor, u8 const *data) 251 { 252 struct roccat_device *device; 253 struct roccat_reader *reader; 254 struct roccat_report *report; 255 uint8_t *new_value; 256 257 device = devices[minor]; 258 259 new_value = kmemdup(data, device->report_size, GFP_ATOMIC); 260 if (!new_value) 261 return -ENOMEM; 262 263 report = &device->cbuf[device->cbuf_end]; 264 265 /* passing NULL is safe */ 266 kfree(report->value); 267 268 report->value = new_value; 269 device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE; 270 271 list_for_each_entry(reader, &device->readers, node) { 272 /* 273 * As we already inserted one element, the buffer can't be 274 * empty. If start and end are equal, buffer is full and we 275 * increase start, so that slow reader misses one event, but 276 * gets the newer ones in the right order. 277 */ 278 if (reader->cbuf_start == device->cbuf_end) 279 reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE; 280 } 281 282 wake_up_interruptible(&device->wait); 283 return 0; 284 } 285 EXPORT_SYMBOL_GPL(roccat_report_event); 286 287 /* 288 * roccat_connect() - create a char device for special event output 289 * @class: the class thats used to create the device. Meant to hold device 290 * specific sysfs attributes. 291 * @hid: the hid device the char device should be connected to. 292 * @report_size: size of reports 293 * 294 * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on 295 * success, a negative error code on failure. 296 */ 297 int roccat_connect(struct class *klass, struct hid_device *hid, int report_size) 298 { 299 unsigned int minor; 300 struct roccat_device *device; 301 int temp; 302 303 device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL); 304 if (!device) 305 return -ENOMEM; 306 307 mutex_lock(&devices_lock); 308 309 for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) { 310 if (devices[minor]) 311 continue; 312 break; 313 } 314 315 if (minor < ROCCAT_MAX_DEVICES) { 316 devices[minor] = device; 317 } else { 318 mutex_unlock(&devices_lock); 319 kfree(device); 320 return -EINVAL; 321 } 322 323 device->dev = device_create(klass, &hid->dev, 324 MKDEV(roccat_major, minor), NULL, 325 "%s%s%d", "roccat", hid->driver->name, minor); 326 327 if (IS_ERR(device->dev)) { 328 devices[minor] = NULL; 329 mutex_unlock(&devices_lock); 330 temp = PTR_ERR(device->dev); 331 kfree(device); 332 return temp; 333 } 334 335 mutex_unlock(&devices_lock); 336 337 init_waitqueue_head(&device->wait); 338 INIT_LIST_HEAD(&device->readers); 339 mutex_init(&device->readers_lock); 340 mutex_init(&device->cbuf_lock); 341 device->minor = minor; 342 device->hid = hid; 343 device->exist = 1; 344 device->cbuf_end = 0; 345 device->report_size = report_size; 346 347 return minor; 348 } 349 EXPORT_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 */ 354 void roccat_disconnect(int minor) 355 { 356 struct roccat_device *device; 357 358 mutex_lock(&devices_lock); 359 device = devices[minor]; 360 mutex_unlock(&devices_lock); 361 362 device->exist = 0; /* TODO exist maybe not needed */ 363 364 device_destroy(device->dev->class, MKDEV(roccat_major, minor)); 365 366 mutex_lock(&devices_lock); 367 devices[minor] = NULL; 368 mutex_unlock(&devices_lock); 369 370 if (device->open) { 371 hid_hw_close(device->hid); 372 wake_up_interruptible(&device->wait); 373 } else { 374 kfree(device); 375 } 376 } 377 EXPORT_SYMBOL_GPL(roccat_disconnect); 378 379 static long roccat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 380 { 381 struct inode *inode = file_inode(file); 382 struct roccat_device *device; 383 unsigned int minor = iminor(inode); 384 long retval = 0; 385 386 mutex_lock(&devices_lock); 387 388 device = devices[minor]; 389 if (!device) { 390 retval = -ENODEV; 391 goto out; 392 } 393 394 switch (cmd) { 395 case ROCCATIOCGREPSIZE: 396 if (put_user(device->report_size, (int __user *)arg)) 397 retval = -EFAULT; 398 break; 399 default: 400 retval = -ENOTTY; 401 } 402 out: 403 mutex_unlock(&devices_lock); 404 return retval; 405 } 406 407 static const struct file_operations roccat_ops = { 408 .owner = THIS_MODULE, 409 .read = roccat_read, 410 .poll = roccat_poll, 411 .open = roccat_open, 412 .release = roccat_release, 413 .llseek = noop_llseek, 414 .unlocked_ioctl = roccat_ioctl, 415 }; 416 417 static int __init roccat_init(void) 418 { 419 int retval; 420 dev_t dev_id; 421 422 retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR, 423 ROCCAT_MAX_DEVICES, "roccat"); 424 if (retval < 0) { 425 pr_warn("can't get major number\n"); 426 goto error; 427 } 428 429 roccat_major = MAJOR(dev_id); 430 431 cdev_init(&roccat_cdev, &roccat_ops); 432 retval = cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); 433 434 if (retval < 0) { 435 pr_warn("cannot add cdev\n"); 436 goto cleanup_alloc_chrdev_region; 437 } 438 return 0; 439 440 441 cleanup_alloc_chrdev_region: 442 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 443 error: 444 return retval; 445 } 446 447 static void __exit roccat_exit(void) 448 { 449 dev_t dev_id = MKDEV(roccat_major, 0); 450 451 cdev_del(&roccat_cdev); 452 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 453 } 454 455 module_init(roccat_init); 456 module_exit(roccat_exit); 457 458 MODULE_AUTHOR("Stefan Achatz"); 459 MODULE_DESCRIPTION("USB Roccat char device"); 460 MODULE_LICENSE("GPL v2"); 461