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 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 38 struct roccat_report { 39 uint8_t *value; 40 int len; 41 }; 42 43 struct 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 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 = 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; 134 135 exit_unlock: 136 mutex_unlock(&device->cbuf_lock); 137 return retval; 138 } 139 140 static 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 } 150 151 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 mutex_lock(&device->readers_lock); 167 168 if (!device) { 169 pr_emerg("roccat device with minor %d doesn't exist\n", minor); 170 error = -ENODEV; 171 goto exit_err; 172 } 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; 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; 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_unlock: 198 mutex_unlock(&device->readers_lock); 199 mutex_unlock(&devices_lock); 200 return error; 201 exit_err: 202 kfree(reader); 203 goto exit_unlock; 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 * @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 */ 251 int 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 } 287 EXPORT_SYMBOL_GPL(roccat_report_event); 288 289 /* 290 * roccat_connect() - create a char device for special event output 291 * @class: the class thats used to create the device. Meant to hold device 292 * specific sysfs attributes. 293 * @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 */ 298 int roccat_connect(struct class *klass, struct hid_device *hid) 299 { 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 } 323 324 device->dev = device_create(klass, &hid->dev, 325 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 } 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 devices[minor] = NULL; 361 mutex_unlock(&devices_lock); 362 363 device->exist = 0; /* TODO exist maybe not needed */ 364 365 device_destroy(device->dev->class, MKDEV(roccat_major, minor)); 366 367 if (device->open) { 368 hid_hw_close(device->hid); 369 wake_up_interruptible(&device->wait); 370 } else { 371 kfree(device); 372 } 373 } 374 EXPORT_SYMBOL_GPL(roccat_disconnect); 375 376 static 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, 382 .llseek = noop_llseek, 383 }; 384 385 static 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) { 396 pr_warn("can't get major number\n"); 397 return retval; 398 } 399 400 cdev_init(&roccat_cdev, &roccat_ops); 401 cdev_add(&roccat_cdev, dev_id, ROCCAT_MAX_DEVICES); 402 403 return 0; 404 } 405 406 static void __exit roccat_exit(void) 407 { 408 dev_t dev_id = MKDEV(roccat_major, 0); 409 410 cdev_del(&roccat_cdev); 411 unregister_chrdev_region(dev_id, ROCCAT_MAX_DEVICES); 412 } 413 414 module_init(roccat_init); 415 module_exit(roccat_exit); 416 417 MODULE_AUTHOR("Stefan Achatz"); 418 MODULE_DESCRIPTION("USB Roccat char device"); 419 MODULE_LICENSE("GPL v2"); 420