Commit | Line | Data |
---|---|---|
cf4b9211 LP |
1 | /* |
2 | * Media device node | |
3 | * | |
4 | * Copyright (C) 2010 Nokia Corporation | |
5 | * | |
6 | * Based on drivers/media/video/v4l2_dev.c code authored by | |
7 | * Mauro Carvalho Chehab <mchehab@infradead.org> (version 2) | |
8 | * Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1) | |
9 | * | |
10 | * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com> | |
11 | * Sakari Ailus <sakari.ailus@iki.fi> | |
12 | * | |
13 | * This program is free software; you can redistribute it and/or modify | |
14 | * it under the terms of the GNU General Public License version 2 as | |
15 | * published by the Free Software Foundation. | |
16 | * | |
17 | * This program is distributed in the hope that it will be useful, | |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | * GNU General Public License for more details. | |
21 | * | |
22 | * You should have received a copy of the GNU General Public License | |
23 | * along with this program; if not, write to the Free Software | |
24 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
25 | * | |
26 | * -- | |
27 | * | |
28 | * Generic media device node infrastructure to register and unregister | |
29 | * character devices using a dynamic major number and proper reference | |
30 | * counting. | |
31 | */ | |
32 | ||
3c16b2b3 SK |
33 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
34 | ||
cf4b9211 LP |
35 | #include <linux/errno.h> |
36 | #include <linux/init.h> | |
37 | #include <linux/module.h> | |
38 | #include <linux/kernel.h> | |
39 | #include <linux/kmod.h> | |
40 | #include <linux/slab.h> | |
41 | #include <linux/mm.h> | |
42 | #include <linux/string.h> | |
43 | #include <linux/types.h> | |
44 | #include <linux/uaccess.h> | |
cf4b9211 LP |
45 | |
46 | #include <media/media-devnode.h> | |
a087ce70 | 47 | #include <media/media-device.h> |
cf4b9211 LP |
48 | |
49 | #define MEDIA_NUM_DEVICES 256 | |
50 | #define MEDIA_NAME "media" | |
51 | ||
52 | static dev_t media_dev_t; | |
53 | ||
54 | /* | |
55 | * Active devices | |
56 | */ | |
57 | static DEFINE_MUTEX(media_devnode_lock); | |
58 | static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES); | |
59 | ||
60 | /* Called when the last user of the media device exits. */ | |
61 | static void media_devnode_release(struct device *cd) | |
62 | { | |
163f1e93 | 63 | struct media_devnode *devnode = to_media_devnode(cd); |
cf4b9211 LP |
64 | |
65 | mutex_lock(&media_devnode_lock); | |
cf4b9211 | 66 | /* Mark device node number as free */ |
163f1e93 | 67 | clear_bit(devnode->minor, media_devnode_nums); |
cf4b9211 LP |
68 | mutex_unlock(&media_devnode_lock); |
69 | ||
70 | /* Release media_devnode and perform other cleanups as needed. */ | |
163f1e93 MCC |
71 | if (devnode->release) |
72 | devnode->release(devnode); | |
a087ce70 MCC |
73 | |
74 | kfree(devnode); | |
5b28dde5 | 75 | pr_debug("%s: Media Devnode Deallocated\n", __func__); |
cf4b9211 LP |
76 | } |
77 | ||
78 | static struct bus_type media_bus_type = { | |
79 | .name = MEDIA_NAME, | |
80 | }; | |
81 | ||
82 | static ssize_t media_read(struct file *filp, char __user *buf, | |
83 | size_t sz, loff_t *off) | |
84 | { | |
163f1e93 | 85 | struct media_devnode *devnode = media_devnode_data(filp); |
cf4b9211 | 86 | |
163f1e93 | 87 | if (!devnode->fops->read) |
cf4b9211 | 88 | return -EINVAL; |
163f1e93 | 89 | if (!media_devnode_is_registered(devnode)) |
cf4b9211 | 90 | return -EIO; |
163f1e93 | 91 | return devnode->fops->read(filp, buf, sz, off); |
cf4b9211 LP |
92 | } |
93 | ||
94 | static ssize_t media_write(struct file *filp, const char __user *buf, | |
95 | size_t sz, loff_t *off) | |
96 | { | |
163f1e93 | 97 | struct media_devnode *devnode = media_devnode_data(filp); |
cf4b9211 | 98 | |
163f1e93 | 99 | if (!devnode->fops->write) |
cf4b9211 | 100 | return -EINVAL; |
163f1e93 | 101 | if (!media_devnode_is_registered(devnode)) |
cf4b9211 | 102 | return -EIO; |
163f1e93 | 103 | return devnode->fops->write(filp, buf, sz, off); |
cf4b9211 LP |
104 | } |
105 | ||
106 | static unsigned int media_poll(struct file *filp, | |
107 | struct poll_table_struct *poll) | |
108 | { | |
163f1e93 | 109 | struct media_devnode *devnode = media_devnode_data(filp); |
cf4b9211 | 110 | |
163f1e93 | 111 | if (!media_devnode_is_registered(devnode)) |
cf4b9211 | 112 | return POLLERR | POLLHUP; |
163f1e93 | 113 | if (!devnode->fops->poll) |
cf4b9211 | 114 | return DEFAULT_POLLMASK; |
163f1e93 | 115 | return devnode->fops->poll(filp, poll); |
cf4b9211 LP |
116 | } |
117 | ||
c6c1d50b SA |
118 | static long |
119 | __media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg, | |
120 | long (*ioctl_func)(struct file *filp, unsigned int cmd, | |
121 | unsigned long arg)) | |
cf4b9211 | 122 | { |
163f1e93 | 123 | struct media_devnode *devnode = media_devnode_data(filp); |
cf4b9211 | 124 | |
c6c1d50b | 125 | if (!ioctl_func) |
cf4b9211 LP |
126 | return -ENOTTY; |
127 | ||
163f1e93 | 128 | if (!media_devnode_is_registered(devnode)) |
cf4b9211 LP |
129 | return -EIO; |
130 | ||
c6c1d50b SA |
131 | return ioctl_func(filp, cmd, arg); |
132 | } | |
133 | ||
134 | static long media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) | |
135 | { | |
163f1e93 | 136 | struct media_devnode *devnode = media_devnode_data(filp); |
c6c1d50b | 137 | |
163f1e93 | 138 | return __media_ioctl(filp, cmd, arg, devnode->fops->ioctl); |
cf4b9211 LP |
139 | } |
140 | ||
c6c1d50b SA |
141 | #ifdef CONFIG_COMPAT |
142 | ||
143 | static long media_compat_ioctl(struct file *filp, unsigned int cmd, | |
144 | unsigned long arg) | |
145 | { | |
163f1e93 | 146 | struct media_devnode *devnode = media_devnode_data(filp); |
c6c1d50b | 147 | |
163f1e93 | 148 | return __media_ioctl(filp, cmd, arg, devnode->fops->compat_ioctl); |
c6c1d50b SA |
149 | } |
150 | ||
151 | #endif /* CONFIG_COMPAT */ | |
152 | ||
cf4b9211 LP |
153 | /* Override for the open function */ |
154 | static int media_open(struct inode *inode, struct file *filp) | |
155 | { | |
163f1e93 | 156 | struct media_devnode *devnode; |
cf4b9211 LP |
157 | int ret; |
158 | ||
159 | /* Check if the media device is available. This needs to be done with | |
160 | * the media_devnode_lock held to prevent an open/unregister race: | |
161 | * without the lock, the device could be unregistered and freed between | |
162 | * the media_devnode_is_registered() and get_device() calls, leading to | |
163 | * a crash. | |
164 | */ | |
165 | mutex_lock(&media_devnode_lock); | |
163f1e93 | 166 | devnode = container_of(inode->i_cdev, struct media_devnode, cdev); |
cf4b9211 LP |
167 | /* return ENXIO if the media device has been removed |
168 | already or if it is not registered anymore. */ | |
163f1e93 | 169 | if (!media_devnode_is_registered(devnode)) { |
cf4b9211 LP |
170 | mutex_unlock(&media_devnode_lock); |
171 | return -ENXIO; | |
172 | } | |
173 | /* and increase the device refcount */ | |
163f1e93 | 174 | get_device(&devnode->dev); |
cf4b9211 LP |
175 | mutex_unlock(&media_devnode_lock); |
176 | ||
163f1e93 | 177 | filp->private_data = devnode; |
cf4b9211 | 178 | |
163f1e93 MCC |
179 | if (devnode->fops->open) { |
180 | ret = devnode->fops->open(filp); | |
cf4b9211 | 181 | if (ret) { |
163f1e93 | 182 | put_device(&devnode->dev); |
d40ec6fd | 183 | filp->private_data = NULL; |
cf4b9211 LP |
184 | return ret; |
185 | } | |
186 | } | |
187 | ||
188 | return 0; | |
189 | } | |
190 | ||
191 | /* Override for the release function */ | |
192 | static int media_release(struct inode *inode, struct file *filp) | |
193 | { | |
163f1e93 | 194 | struct media_devnode *devnode = media_devnode_data(filp); |
cf4b9211 | 195 | |
163f1e93 MCC |
196 | if (devnode->fops->release) |
197 | devnode->fops->release(filp); | |
cf4b9211 | 198 | |
bf244f66 MK |
199 | filp->private_data = NULL; |
200 | ||
cf4b9211 LP |
201 | /* decrease the refcount unconditionally since the release() |
202 | return value is ignored. */ | |
163f1e93 | 203 | put_device(&devnode->dev); |
5b28dde5 SK |
204 | |
205 | pr_debug("%s: Media Release\n", __func__); | |
8b37c645 | 206 | return 0; |
cf4b9211 LP |
207 | } |
208 | ||
209 | static const struct file_operations media_devnode_fops = { | |
210 | .owner = THIS_MODULE, | |
211 | .read = media_read, | |
212 | .write = media_write, | |
213 | .open = media_open, | |
214 | .unlocked_ioctl = media_ioctl, | |
c6c1d50b SA |
215 | #ifdef CONFIG_COMPAT |
216 | .compat_ioctl = media_compat_ioctl, | |
217 | #endif /* CONFIG_COMPAT */ | |
cf4b9211 LP |
218 | .release = media_release, |
219 | .poll = media_poll, | |
220 | .llseek = no_llseek, | |
221 | }; | |
222 | ||
a087ce70 MCC |
223 | int __must_check media_devnode_register(struct media_device *mdev, |
224 | struct media_devnode *devnode, | |
85de721c | 225 | struct module *owner) |
cf4b9211 LP |
226 | { |
227 | int minor; | |
228 | int ret; | |
229 | ||
230 | /* Part 1: Find a free minor number */ | |
231 | mutex_lock(&media_devnode_lock); | |
8c89ddd5 | 232 | minor = find_next_zero_bit(media_devnode_nums, MEDIA_NUM_DEVICES, 0); |
cf4b9211 LP |
233 | if (minor == MEDIA_NUM_DEVICES) { |
234 | mutex_unlock(&media_devnode_lock); | |
3c16b2b3 | 235 | pr_err("could not get a free minor\n"); |
5b28dde5 | 236 | kfree(devnode); |
cf4b9211 LP |
237 | return -ENFILE; |
238 | } | |
239 | ||
8c89ddd5 | 240 | set_bit(minor, media_devnode_nums); |
cf4b9211 LP |
241 | mutex_unlock(&media_devnode_lock); |
242 | ||
163f1e93 | 243 | devnode->minor = minor; |
a087ce70 | 244 | devnode->media_dev = mdev; |
cf4b9211 | 245 | |
5b28dde5 SK |
246 | /* Part 1: Initialize dev now to use dev.kobj for cdev.kobj.parent */ |
247 | devnode->dev.bus = &media_bus_type; | |
248 | devnode->dev.devt = MKDEV(MAJOR(media_dev_t), devnode->minor); | |
249 | devnode->dev.release = media_devnode_release; | |
250 | if (devnode->parent) | |
251 | devnode->dev.parent = devnode->parent; | |
252 | dev_set_name(&devnode->dev, "media%d", devnode->minor); | |
253 | device_initialize(&devnode->dev); | |
254 | ||
cf4b9211 | 255 | /* Part 2: Initialize and register the character device */ |
163f1e93 MCC |
256 | cdev_init(&devnode->cdev, &media_devnode_fops); |
257 | devnode->cdev.owner = owner; | |
5b28dde5 | 258 | devnode->cdev.kobj.parent = &devnode->dev.kobj; |
cf4b9211 | 259 | |
163f1e93 | 260 | ret = cdev_add(&devnode->cdev, MKDEV(MAJOR(media_dev_t), devnode->minor), 1); |
cf4b9211 | 261 | if (ret < 0) { |
3c16b2b3 | 262 | pr_err("%s: cdev_add failed\n", __func__); |
5b28dde5 | 263 | goto cdev_add_error; |
cf4b9211 LP |
264 | } |
265 | ||
5b28dde5 SK |
266 | /* Part 3: Add the media device */ |
267 | ret = device_add(&devnode->dev); | |
cf4b9211 | 268 | if (ret < 0) { |
5b28dde5 SK |
269 | pr_err("%s: device_add failed\n", __func__); |
270 | goto device_add_error; | |
cf4b9211 LP |
271 | } |
272 | ||
273 | /* Part 4: Activate this minor. The char device can now be used. */ | |
163f1e93 | 274 | set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); |
cf4b9211 LP |
275 | |
276 | return 0; | |
277 | ||
5b28dde5 | 278 | device_add_error: |
163f1e93 | 279 | cdev_del(&devnode->cdev); |
5b28dde5 SK |
280 | cdev_add_error: |
281 | mutex_lock(&media_devnode_lock); | |
163f1e93 | 282 | clear_bit(devnode->minor, media_devnode_nums); |
5b28dde5 | 283 | devnode->media_dev = NULL; |
88336e17 MK |
284 | mutex_unlock(&media_devnode_lock); |
285 | ||
5b28dde5 | 286 | put_device(&devnode->dev); |
cf4b9211 LP |
287 | return ret; |
288 | } | |
289 | ||
6f0dd24a | 290 | void media_devnode_unregister_prepare(struct media_devnode *devnode) |
cf4b9211 | 291 | { |
163f1e93 MCC |
292 | /* Check if devnode was ever registered at all */ |
293 | if (!media_devnode_is_registered(devnode)) | |
cf4b9211 LP |
294 | return; |
295 | ||
296 | mutex_lock(&media_devnode_lock); | |
163f1e93 | 297 | clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); |
6f0dd24a SK |
298 | mutex_unlock(&media_devnode_lock); |
299 | } | |
300 | ||
301 | void media_devnode_unregister(struct media_devnode *devnode) | |
302 | { | |
303 | mutex_lock(&media_devnode_lock); | |
5b28dde5 SK |
304 | /* Delete the cdev on this minor as well */ |
305 | cdev_del(&devnode->cdev); | |
cf4b9211 | 306 | mutex_unlock(&media_devnode_lock); |
5b28dde5 SK |
307 | device_del(&devnode->dev); |
308 | devnode->media_dev = NULL; | |
309 | put_device(&devnode->dev); | |
cf4b9211 LP |
310 | } |
311 | ||
312 | /* | |
313 | * Initialise media for linux | |
314 | */ | |
315 | static int __init media_devnode_init(void) | |
316 | { | |
317 | int ret; | |
318 | ||
3c16b2b3 | 319 | pr_info("Linux media interface: v0.10\n"); |
cf4b9211 LP |
320 | ret = alloc_chrdev_region(&media_dev_t, 0, MEDIA_NUM_DEVICES, |
321 | MEDIA_NAME); | |
322 | if (ret < 0) { | |
3c16b2b3 | 323 | pr_warn("unable to allocate major\n"); |
cf4b9211 LP |
324 | return ret; |
325 | } | |
326 | ||
327 | ret = bus_register(&media_bus_type); | |
328 | if (ret < 0) { | |
329 | unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); | |
3c16b2b3 | 330 | pr_warn("bus_register failed\n"); |
cf4b9211 LP |
331 | return -EIO; |
332 | } | |
333 | ||
334 | return 0; | |
335 | } | |
336 | ||
337 | static void __exit media_devnode_exit(void) | |
338 | { | |
339 | bus_unregister(&media_bus_type); | |
340 | unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); | |
341 | } | |
342 | ||
ff732d28 | 343 | subsys_initcall(media_devnode_init); |
cf4b9211 LP |
344 | module_exit(media_devnode_exit) |
345 | ||
346 | MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>"); | |
347 | MODULE_DESCRIPTION("Device node registration for media drivers"); | |
348 | MODULE_LICENSE("GPL"); |