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.h> 29 #include <linux/hid-roccat.h> 30 31 #define ROCCAT_FIRST_MINOR 0 32 #define ROCCAT_MAX_DEVICES 8 33 34 /* should be a power of 2 for performance reason */ 35 #define ROCCAT_CBUF_SIZE 16 36 37 struct roccat_report { 38 uint8_t *value; 39 }; 40 41 struct roccat_device { 42 unsigned int minor; 43 int report_size; 44 int open; 45 int exist; 46 wait_queue_head_t wait; 47 struct device *dev; 48 struct hid_device *hid; 49 struct list_head readers; 50 /* protects modifications of readers list */ 51 struct mutex readers_lock; 52 53 /* 54 * circular_buffer has one writer and multiple readers with their own 55 * read pointers 56 */ 57 struct roccat_report cbuf[ROCCAT_CBUF_SIZE]; 58 int cbuf_end; 59 struct mutex cbuf_lock; 60 }; 61 62 struct roccat_reader { 63 struct list_head node; 64 struct roccat_device *device; 65 int cbuf_start; 66 }; 67 68 static int roccat_major; 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 = device->report_size > count ? count : device->report_size; 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 pr_emerg("roccat device with minor %d doesn't exist\n", minor); 169 error = -ENODEV; 170 goto exit_err; 171 } 172 173 if (!device->open++) { 174 /* power on device on adding first reader */ 175 error = hid_hw_power(device->hid, PM_HINT_FULLON); 176 if (error < 0) { 177 --device->open; 178 goto exit_err; 179 } 180 181 error = hid_hw_open(device->hid); 182 if (error < 0) { 183 hid_hw_power(device->hid, PM_HINT_NORMAL); 184 --device->open; 185 goto exit_err; 186 } 187 } 188 189 reader->device = device; 190 /* new reader doesn't get old events */ 191 reader->cbuf_start = device->cbuf_end; 192 193 list_add_tail(&reader->node, &device->readers); 194 file->private_data = reader; 195 196 exit_unlock: 197 mutex_unlock(&device->readers_lock); 198 mutex_unlock(&devices_lock); 199 return error; 200 exit_err: 201 kfree(reader); 202 goto exit_unlock; 203 } 204 205 static int roccat_release(struct inode *inode, struct file *file) 206 { 207 unsigned int minor = iminor(inode); 208 struct roccat_reader *reader = file->private_data; 209 struct roccat_device *device; 210 211 mutex_lock(&devices_lock); 212 213 device = devices[minor]; 214 if (!device) { 215 mutex_unlock(&devices_lock); 216 pr_emerg("roccat device with minor %d doesn't exist\n", minor); 217 return -ENODEV; 218 } 219 220 mutex_lock(&device->readers_lock); 221 list_del(&reader->node); 222 mutex_unlock(&device->readers_lock); 223 kfree(reader); 224 225 if (!--device->open) { 226 /* removing last reader */ 227 if (device->exist) { 228 hid_hw_power(device->hid, PM_HINT_NORMAL); 229 hid_hw_close(device->hid); 230 } else { 231 kfree(device); 232 } 233 } 234 235 mutex_unlock(&devices_lock); 236 237 return 0; 238 } 239 240 /* 241 * roccat_report_event() - output data to readers 242 * @minor: minor device number returned by roccat_connect() 243 * @data: pointer to data 244 * @len: size of 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 * 293 * Return value is minor device number in Range [0, ROCCAT_MAX_DEVICES] on 294 * success, a negative error code on failure. 295 */ 296 int roccat_connect(struct class *klass, struct hid_device *hid, int report_size) 297 { 298 unsigned int minor; 299 struct roccat_device *device; 300 int temp; 301 302 device = kzalloc(sizeof(struct roccat_device), GFP_KERNEL); 303 if (!device) 304 return -ENOMEM; 305 306 mutex_lock(&devices_lock); 307 308 for (minor = 0; minor < ROCCAT_MAX_DEVICES; ++minor) { 309 if (devices[minor]) 310 continue; 311 break; 312 } 313 314 if (minor < ROCCAT_MAX_DEVICES) { 315 devices[minor] = device; 316 } else { 317 mutex_unlock(&devices_lock); 318 kfree(device); 319 return -EINVAL; 320 } 321 322 device->dev = device_create(klass, &hid->dev, 323 MKDEV(roccat_major, minor), NULL, 324 "%s%s%d", "roccat", hid->driver->name, minor); 325 326 if (IS_ERR(device->dev)) { 327 devices[minor] = NULL; 328 mutex_unlock(&devices_lock); 329 temp = PTR_ERR(device->dev); 330 kfree(device); 331 return temp; 332 } 333 334 mutex_unlock(&devices_lock); 335 336 init_waitqueue_head(&device->wait); 337 INIT_LIST_HEAD(&device->readers); 338 mutex_init(&device->readers_lock); 339 mutex_init(&device->cbuf_lock); 340 device->minor = minor; 341 device->hid = hid; 342 device->exist = 1; 343 device->cbuf_end = 0; 344 device->report_size = report_size; 345 346 return minor; 347 } 348 EXPORT_SYMBOL_GPL(roccat_connect); 349 350 /* roccat_disconnect() - remove char device from hid device 351 * @minor: the minor device number returned by roccat_connect() 352 */ 353 void roccat_disconnect(int minor) 354 { 355 struct roccat_device *device; 356 357 mutex_lock(&devices_lock); 358 device = devices[minor]; 359 mutex_unlock(&devices_lock); 360 361 device->exist = 0; /* TODO exist maybe not needed */ 362 363 device_destroy(device->dev->class, MKDEV(roccat_major, minor)); 364 365 mutex_lock(&devices_lock); 366 devices[minor] = NULL; 367 mutex_unlock(&devices_lock); 368 369 if (device->open) { 370 hid_hw_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 long roccat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 379 { 380 struct inode *inode = file->f_path.dentry->d_inode; 381 struct roccat_device *device; 382 unsigned int minor = iminor(inode); 383 long retval = 0; 384 385 mutex_lock(&devices_lock); 386 387 device = devices[minor]; 388 if (!device) { 389 retval = -ENODEV; 390 goto out; 391 } 392 393 switch (cmd) { 394 case ROCCATIOCGREPSIZE: 395 if (put_user(device->report_size, (int __user *)arg)) 396 retval = -EFAULT; 397 break; 398 default: 399 retval = -ENOTTY; 400 } 401 out: 402 mutex_unlock(&devices_lock); 403 return retval; 404 } 405 406 static const struct file_operations roccat_ops = { 407 .owner = THIS_MODULE, 408 .read = roccat_read, 409 .poll = roccat_poll, 410 .open = roccat_open, 411 .release = roccat_release, 412 .llseek = noop_llseek, 413 .unlocked_ioctl = roccat_ioctl, 414 }; 415 416 static int __init roccat_init(void) 417 { 418 int retval; 419 dev_t dev_id; 420 421 retval = alloc_chrdev_region(&dev_id, ROCCAT_FIRST_MINOR, 422 ROCCAT_MAX_DEVICES, "roccat"); 423 424 roccat_major = MAJOR(dev_id); 425 426 if (retval < 0) { 427 pr_warn("can't get major number\n"); 428 return retval; 429 } 430 431 cdev_init(&roccat_cdev, &roccat_ops); 432 cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); 433 434 return 0; 435 } 436 437 static void __exit roccat_exit(void) 438 { 439 dev_t dev_id = MKDEV(roccat_major, 0); 440 441 cdev_del(&roccat_cdev); 442 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 443 } 444 445 module_init(roccat_init); 446 module_exit(roccat_exit); 447 448 MODULE_AUTHOR("Stefan Achatz"); 449 MODULE_DESCRIPTION("USB Roccat char device"); 450 MODULE_LICENSE("GPL v2"); 451