1 /* 2 * HID raw devices, giving access to raw HID events. 3 * 4 * In comparison to hiddev, this device does not process the 5 * hid events at all (no parsing, no lookups). This lets applications 6 * to work on raw hid events as they want to, and avoids a need to 7 * use a transport-specific userspace libhid/libusb libraries. 8 * 9 * Copyright (c) 2007 Jiri Kosina 10 */ 11 12 /* 13 * This program is free software; you can redistribute it and/or modify it 14 * under the terms and conditions of the GNU General Public License, 15 * version 2, as published by the Free Software Foundation. 16 * 17 * You should have received a copy of the GNU General Public License along with 18 * this program; if not, write to the Free Software Foundation, Inc., 19 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. 20 */ 21 22 #include <linux/fs.h> 23 #include <linux/module.h> 24 #include <linux/errno.h> 25 #include <linux/kernel.h> 26 #include <linux/init.h> 27 #include <linux/cdev.h> 28 #include <linux/poll.h> 29 #include <linux/device.h> 30 #include <linux/major.h> 31 #include <linux/hid.h> 32 #include <linux/mutex.h> 33 34 #include <linux/hidraw.h> 35 36 static int hidraw_major; 37 static struct cdev hidraw_cdev; 38 static struct class *hidraw_class; 39 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; 40 static DEFINE_SPINLOCK(minors_lock); 41 42 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) 43 { 44 struct hidraw_list *list = file->private_data; 45 int ret = 0, len; 46 char *report; 47 DECLARE_WAITQUEUE(wait, current); 48 49 while (ret == 0) { 50 51 mutex_lock(&list->read_mutex); 52 53 if (list->head == list->tail) { 54 add_wait_queue(&list->hidraw->wait, &wait); 55 set_current_state(TASK_INTERRUPTIBLE); 56 57 while (list->head == list->tail) { 58 if (file->f_flags & O_NONBLOCK) { 59 ret = -EAGAIN; 60 break; 61 } 62 if (signal_pending(current)) { 63 ret = -ERESTARTSYS; 64 break; 65 } 66 if (!list->hidraw->exist) { 67 ret = -EIO; 68 break; 69 } 70 71 /* allow O_NONBLOCK to work well from other threads */ 72 mutex_unlock(&list->read_mutex); 73 schedule(); 74 mutex_lock(&list->read_mutex); 75 set_current_state(TASK_INTERRUPTIBLE); 76 } 77 78 set_current_state(TASK_RUNNING); 79 remove_wait_queue(&list->hidraw->wait, &wait); 80 } 81 82 if (ret) 83 goto out; 84 85 report = list->buffer[list->tail].value; 86 len = list->buffer[list->tail].len > count ? 87 count : list->buffer[list->tail].len; 88 89 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) { 90 ret = -EFAULT; 91 goto out; 92 } 93 ret += len; 94 95 kfree(list->buffer[list->tail].value); 96 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); 97 } 98 out: 99 mutex_unlock(&list->read_mutex); 100 return ret; 101 } 102 103 /* the first byte is expected to be a report number */ 104 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) 105 { 106 unsigned int minor = iminor(file->f_path.dentry->d_inode); 107 struct hid_device *dev = hidraw_table[minor]->hid; 108 __u8 *buf; 109 int ret = 0; 110 111 if (!dev->hid_output_raw_report) 112 return -ENODEV; 113 114 if (count > HID_MIN_BUFFER_SIZE) { 115 printk(KERN_WARNING "hidraw: pid %d passed too large report\n", 116 task_pid_nr(current)); 117 return -EINVAL; 118 } 119 120 if (count < 2) { 121 printk(KERN_WARNING "hidraw: pid %d passed too short report\n", 122 task_pid_nr(current)); 123 return -EINVAL; 124 } 125 126 buf = kmalloc(count * sizeof(__u8), GFP_KERNEL); 127 if (!buf) 128 return -ENOMEM; 129 130 if (copy_from_user(buf, buffer, count)) { 131 ret = -EFAULT; 132 goto out; 133 } 134 135 ret = dev->hid_output_raw_report(dev, buf, count); 136 out: 137 kfree(buf); 138 return ret; 139 } 140 141 static unsigned int hidraw_poll(struct file *file, poll_table *wait) 142 { 143 struct hidraw_list *list = file->private_data; 144 145 poll_wait(file, &list->hidraw->wait, wait); 146 if (list->head != list->tail) 147 return POLLIN | POLLRDNORM; 148 if (!list->hidraw->exist) 149 return POLLERR | POLLHUP; 150 return 0; 151 } 152 153 static int hidraw_open(struct inode *inode, struct file *file) 154 { 155 unsigned int minor = iminor(inode); 156 struct hidraw *dev; 157 struct hidraw_list *list; 158 int err = 0; 159 160 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { 161 err = -ENOMEM; 162 goto out; 163 } 164 165 spin_lock(&minors_lock); 166 if (!hidraw_table[minor]) { 167 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n", 168 minor); 169 kfree(list); 170 err = -ENODEV; 171 goto out_unlock; 172 } 173 174 list->hidraw = hidraw_table[minor]; 175 mutex_init(&list->read_mutex); 176 list_add_tail(&list->node, &hidraw_table[minor]->list); 177 file->private_data = list; 178 179 dev = hidraw_table[minor]; 180 if (!dev->open++) 181 dev->hid->hid_open(dev->hid); 182 183 out_unlock: 184 spin_unlock(&minors_lock); 185 out: 186 return err; 187 188 } 189 190 static int hidraw_release(struct inode * inode, struct file * file) 191 { 192 unsigned int minor = iminor(inode); 193 struct hidraw *dev; 194 struct hidraw_list *list = file->private_data; 195 196 if (!hidraw_table[minor]) { 197 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n", 198 minor); 199 return -ENODEV; 200 } 201 202 list_del(&list->node); 203 dev = hidraw_table[minor]; 204 if (!dev->open--) { 205 if (list->hidraw->exist) 206 dev->hid->hid_close(dev->hid); 207 else 208 kfree(list->hidraw); 209 } 210 211 return 0; 212 } 213 214 static int hidraw_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) 215 { 216 unsigned int minor = iminor(inode); 217 struct hidraw *dev = hidraw_table[minor]; 218 void __user *user_arg = (void __user*) arg; 219 220 switch (cmd) { 221 case HIDIOCGRDESCSIZE: 222 if (put_user(dev->hid->rsize, (int __user *)arg)) 223 return -EFAULT; 224 return 0; 225 226 case HIDIOCGRDESC: 227 { 228 __u32 len; 229 230 if (get_user(len, (int __user *)arg)) 231 return -EFAULT; 232 233 if (len > HID_MAX_DESCRIPTOR_SIZE - 1) 234 return -EINVAL; 235 236 if (copy_to_user(user_arg + offsetof( 237 struct hidraw_report_descriptor, 238 value[0]), 239 dev->hid->rdesc, 240 min(dev->hid->rsize, len))) 241 return -EFAULT; 242 return 0; 243 } 244 case HIDIOCGRAWINFO: 245 { 246 struct hidraw_devinfo dinfo; 247 248 dinfo.bustype = dev->hid->bus; 249 dinfo.vendor = dev->hid->vendor; 250 dinfo.product = dev->hid->product; 251 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) 252 return -EFAULT; 253 254 return 0; 255 } 256 default: 257 printk(KERN_EMERG "hidraw: unsupported ioctl() %x\n", 258 cmd); 259 } 260 return -EINVAL; 261 } 262 263 static const struct file_operations hidraw_ops = { 264 .owner = THIS_MODULE, 265 .read = hidraw_read, 266 .write = hidraw_write, 267 .poll = hidraw_poll, 268 .open = hidraw_open, 269 .release = hidraw_release, 270 .ioctl = hidraw_ioctl, 271 }; 272 273 void hidraw_report_event(struct hid_device *hid, u8 *data, int len) 274 { 275 struct hidraw *dev = hid->hidraw; 276 struct hidraw_list *list; 277 278 list_for_each_entry(list, &dev->list, node) { 279 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC); 280 list->buffer[list->head].len = len; 281 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); 282 kill_fasync(&list->fasync, SIGIO, POLL_IN); 283 } 284 285 wake_up_interruptible(&dev->wait); 286 } 287 EXPORT_SYMBOL_GPL(hidraw_report_event); 288 289 int hidraw_connect(struct hid_device *hid) 290 { 291 int minor, result; 292 struct hidraw *dev; 293 294 /* TODO currently we accept any HID device. This should later 295 * probably be fixed to accept only those devices which provide 296 * non-input applications 297 */ 298 299 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); 300 if (!dev) 301 return -ENOMEM; 302 303 result = -EINVAL; 304 305 spin_lock(&minors_lock); 306 307 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { 308 if (hidraw_table[minor]) 309 continue; 310 hidraw_table[minor] = dev; 311 result = 0; 312 break; 313 } 314 315 spin_unlock(&minors_lock); 316 317 if (result) { 318 kfree(dev); 319 goto out; 320 } 321 322 dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor), 323 "%s%d", "hidraw", minor); 324 325 if (IS_ERR(dev->dev)) { 326 spin_lock(&minors_lock); 327 hidraw_table[minor] = NULL; 328 spin_unlock(&minors_lock); 329 result = PTR_ERR(dev->dev); 330 kfree(dev); 331 goto out; 332 } 333 334 init_waitqueue_head(&dev->wait); 335 INIT_LIST_HEAD(&dev->list); 336 337 dev->hid = hid; 338 dev->minor = minor; 339 340 dev->exist = 1; 341 hid->hidraw = dev; 342 343 out: 344 return result; 345 346 } 347 EXPORT_SYMBOL_GPL(hidraw_connect); 348 349 void hidraw_disconnect(struct hid_device *hid) 350 { 351 struct hidraw *hidraw = hid->hidraw; 352 353 hidraw->exist = 0; 354 355 spin_lock(&minors_lock); 356 hidraw_table[hidraw->minor] = NULL; 357 spin_unlock(&minors_lock); 358 359 device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor)); 360 361 if (hidraw->open) { 362 hid->hid_close(hid); 363 wake_up_interruptible(&hidraw->wait); 364 } else { 365 kfree(hidraw); 366 } 367 } 368 EXPORT_SYMBOL_GPL(hidraw_disconnect); 369 370 int __init hidraw_init(void) 371 { 372 int result; 373 dev_t dev_id; 374 375 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR, 376 HIDRAW_MAX_DEVICES, "hidraw"); 377 378 hidraw_major = MAJOR(dev_id); 379 380 if (result < 0) { 381 printk(KERN_WARNING "hidraw: can't get major number\n"); 382 result = 0; 383 goto out; 384 } 385 386 hidraw_class = class_create(THIS_MODULE, "hidraw"); 387 if (IS_ERR(hidraw_class)) { 388 result = PTR_ERR(hidraw_class); 389 unregister_chrdev(hidraw_major, "hidraw"); 390 goto out; 391 } 392 393 cdev_init(&hidraw_cdev, &hidraw_ops); 394 cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); 395 out: 396 return result; 397 } 398 399 void __exit hidraw_exit(void) 400 { 401 dev_t dev_id = MKDEV(hidraw_major, 0); 402 403 cdev_del(&hidraw_cdev); 404 class_destroy(hidraw_class); 405 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES); 406 407 } 408