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_unlock; 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_unlock; 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_unlock; 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 } 206 207 static int roccat_release(struct inode *inode, struct file *file) 208 { 209 unsigned int minor = iminor(inode); 210 struct roccat_reader *reader = file->private_data; 211 struct roccat_device *device; 212 213 mutex_lock(&devices_lock); 214 215 device = devices[minor]; 216 if (!device) { 217 mutex_unlock(&devices_lock); 218 printk(KERN_EMERG "roccat device with minor %d doesn't exist\n", 219 minor); 220 return -ENODEV; 221 } 222 223 mutex_lock(&device->readers_lock); 224 list_del(&reader->node); 225 mutex_unlock(&device->readers_lock); 226 kfree(reader); 227 228 if (!--device->open) { 229 /* removing last reader */ 230 if (device->exist) { 231 if (device->hid->ll_driver->power) 232 device->hid->ll_driver->power(device->hid, 233 PM_HINT_NORMAL); 234 device->hid->ll_driver->close(device->hid); 235 } else { 236 kfree(device); 237 } 238 } 239 240 mutex_unlock(&devices_lock); 241 242 return 0; 243 } 244 245 /* 246 * roccat_report_event() - output data to readers 247 * @minor: minor device number returned by roccat_connect() 248 * @data: pointer to data 249 * @len: size of data 250 * 251 * Return value is zero on success, a negative error code on failure. 252 * 253 * This is called from interrupt handler. 254 */ 255 int roccat_report_event(int minor, u8 const *data, int len) 256 { 257 struct roccat_device *device; 258 struct roccat_reader *reader; 259 struct roccat_report *report; 260 uint8_t *new_value; 261 262 new_value = kmemdup(data, len, GFP_ATOMIC); 263 if (!new_value) 264 return -ENOMEM; 265 266 device = devices[minor]; 267 268 report = &device->cbuf[device->cbuf_end]; 269 270 /* passing NULL is safe */ 271 kfree(report->value); 272 273 report->value = new_value; 274 report->len = len; 275 device->cbuf_end = (device->cbuf_end + 1) % ROCCAT_CBUF_SIZE; 276 277 list_for_each_entry(reader, &device->readers, node) { 278 /* 279 * As we already inserted one element, the buffer can't be 280 * empty. If start and end are equal, buffer is full and we 281 * increase start, so that slow reader misses one event, but 282 * gets the newer ones in the right order. 283 */ 284 if (reader->cbuf_start == device->cbuf_end) 285 reader->cbuf_start = (reader->cbuf_start + 1) % ROCCAT_CBUF_SIZE; 286 } 287 288 wake_up_interruptible(&device->wait); 289 return 0; 290 } 291 EXPORT_SYMBOL_GPL(roccat_report_event); 292 293 /* 294 * roccat_connect() - create a char device for special event output 295 * @hid: the hid device the char device should be connected to. 296 * 297 * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on 298 * success, a negative error code on failure. 299 */ 300 int roccat_connect(struct hid_device *hid) 301 { 302 unsigned int minor; 303 struct roccat_device *device; 304 int temp; 305 306 device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL); 307 if (!device) 308 return -ENOMEM; 309 310 mutex_lock(&devices_lock); 311 312 for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) { 313 if (devices[minor]) 314 continue; 315 break; 316 } 317 318 if (minor < ROCCAT_MAX_DEVICES) { 319 devices[minor] = device; 320 } else { 321 mutex_unlock(&devices_lock); 322 kfree(device); 323 return -EINVAL; 324 } 325 326 device->dev = device_create(roccat_class, &hid->dev, 327 MKDEV(roccat_major, minor), NULL, 328 "%s%s%d", "roccat", hid->driver->name, minor); 329 330 if (IS_ERR(device->dev)) { 331 devices[minor] = NULL; 332 mutex_unlock(&devices_lock); 333 temp = PTR_ERR(device->dev); 334 kfree(device); 335 return temp; 336 } 337 338 mutex_unlock(&devices_lock); 339 340 init_waitqueue_head(&device->wait); 341 INIT_LIST_HEAD(&device->readers); 342 mutex_init(&device->readers_lock); 343 mutex_init(&device->cbuf_lock); 344 device->minor = minor; 345 device->hid = hid; 346 device->exist = 1; 347 device->cbuf_end = 0; 348 349 return minor; 350 } 351 EXPORT_SYMBOL_GPL(roccat_connect); 352 353 /* roccat_disconnect() - remove char device from hid device 354 * @minor: the minor device number returned by roccat_connect() 355 */ 356 void roccat_disconnect(int minor) 357 { 358 struct roccat_device *device; 359 360 mutex_lock(&devices_lock); 361 device = devices[minor]; 362 devices[minor] = NULL; 363 mutex_unlock(&devices_lock); 364 365 device->exist = 0; /* TODO exist maybe not needed */ 366 367 device_destroy(roccat_class, MKDEV(roccat_major, minor)); 368 369 if (device->open) { 370 device->hid->ll_driver->close(device->hid); 371 wake_up_interruptible(&device->wait); 372 } else { 373 kfree(device); 374 } 375 } 376 EXPORT_SYMBOL_GPL(roccat_disconnect); 377 378 static const struct file_operations roccat_ops = { 379 .owner = THIS_MODULE, 380 .read = roccat_read, 381 .poll = roccat_poll, 382 .open = roccat_open, 383 .release = roccat_release, 384 }; 385 386 static int __init roccat_init(void) 387 { 388 int retval; 389 dev_t dev_id; 390 391 retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR, 392 ROCCAT_MAX_DEVICES, "roccat"); 393 394 roccat_major = MAJOR(dev_id); 395 396 if (retval < 0) { 397 printk(KERN_WARNING "roccat: can't get major number\n"); 398 return retval; 399 } 400 401 roccat_class = class_create(THIS_MODULE, "roccat"); 402 if (IS_ERR(roccat_class)) { 403 retval = PTR_ERR(roccat_class); 404 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 405 return retval; 406 } 407 408 cdev_init(&roccat_cdev, &roccat_ops); 409 cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); 410 411 return 0; 412 } 413 414 static void __exit roccat_exit(void) 415 { 416 dev_t dev_id = MKDEV(roccat_major, 0); 417 418 cdev_del(&roccat_cdev); 419 class_destroy(roccat_class); 420 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 421 } 422 423 module_init(roccat_init); 424 module_exit(roccat_exit); 425 426 MODULE_AUTHOR("Stefan Achatz"); 427 MODULE_DESCRIPTION("USB Roccat char device"); 428 MODULE_LICENSE("GPL v2"); 429