1 /* 2 * v4l2-fh.c 3 * 4 * V4L2 file handles. 5 * 6 * Copyright (C) 2009--2010 Nokia Corporation. 7 * 8 * Contact: Sakari Ailus <sakari.ailus@iki.fi> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * version 2 as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, but 15 * WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 17 * General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to the Free Software 21 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 22 * 02110-1301 USA 23 */ 24 25 #include <linux/bitops.h> 26 #include <linux/slab.h> 27 #include <linux/export.h> 28 #include <media/v4l2-dev.h> 29 #include <media/v4l2-fh.h> 30 #include <media/v4l2-event.h> 31 #include <media/v4l2-ioctl.h> 32 33 void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev) 34 { 35 fh->vdev = vdev; 36 /* Inherit from video_device. May be overridden by the driver. */ 37 fh->ctrl_handler = vdev->ctrl_handler; 38 INIT_LIST_HEAD(&fh->list); 39 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags); 40 /* 41 * determine_valid_ioctls() does not know if struct v4l2_fh 42 * is used by this driver, but here we do. So enable the 43 * prio ioctls here. 44 */ 45 set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls); 46 set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls); 47 fh->prio = V4L2_PRIORITY_UNSET; 48 init_waitqueue_head(&fh->wait); 49 INIT_LIST_HEAD(&fh->available); 50 INIT_LIST_HEAD(&fh->subscribed); 51 fh->sequence = -1; 52 } 53 EXPORT_SYMBOL_GPL(v4l2_fh_init); 54 55 void v4l2_fh_add(struct v4l2_fh *fh) 56 { 57 unsigned long flags; 58 59 v4l2_prio_open(fh->vdev->prio, &fh->prio); 60 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 61 list_add(&fh->list, &fh->vdev->fh_list); 62 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 63 } 64 EXPORT_SYMBOL_GPL(v4l2_fh_add); 65 66 int v4l2_fh_open(struct file *filp) 67 { 68 struct video_device *vdev = video_devdata(filp); 69 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL); 70 71 filp->private_data = fh; 72 if (fh == NULL) 73 return -ENOMEM; 74 v4l2_fh_init(fh, vdev); 75 v4l2_fh_add(fh); 76 return 0; 77 } 78 EXPORT_SYMBOL_GPL(v4l2_fh_open); 79 80 void v4l2_fh_del(struct v4l2_fh *fh) 81 { 82 unsigned long flags; 83 84 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 85 list_del_init(&fh->list); 86 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 87 v4l2_prio_close(fh->vdev->prio, fh->prio); 88 } 89 EXPORT_SYMBOL_GPL(v4l2_fh_del); 90 91 void v4l2_fh_exit(struct v4l2_fh *fh) 92 { 93 if (fh->vdev == NULL) 94 return; 95 v4l2_event_unsubscribe_all(fh); 96 fh->vdev = NULL; 97 } 98 EXPORT_SYMBOL_GPL(v4l2_fh_exit); 99 100 int v4l2_fh_release(struct file *filp) 101 { 102 struct v4l2_fh *fh = filp->private_data; 103 104 if (fh) { 105 v4l2_fh_del(fh); 106 v4l2_fh_exit(fh); 107 kfree(fh); 108 } 109 return 0; 110 } 111 EXPORT_SYMBOL_GPL(v4l2_fh_release); 112 113 int v4l2_fh_is_singular(struct v4l2_fh *fh) 114 { 115 unsigned long flags; 116 int is_singular; 117 118 if (fh == NULL || fh->vdev == NULL) 119 return 0; 120 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 121 is_singular = list_is_singular(&fh->list); 122 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 123 return is_singular; 124 } 125 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular); 126