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@maxwell.research.nokia.com> 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 fh->prio = V4L2_PRIORITY_UNSET; 41 init_waitqueue_head(&fh->wait); 42 INIT_LIST_HEAD(&fh->available); 43 INIT_LIST_HEAD(&fh->subscribed); 44 fh->sequence = -1; 45 } 46 EXPORT_SYMBOL_GPL(v4l2_fh_init); 47 48 void v4l2_fh_add(struct v4l2_fh *fh) 49 { 50 unsigned long flags; 51 52 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags)) 53 v4l2_prio_open(fh->vdev->prio, &fh->prio); 54 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 55 list_add(&fh->list, &fh->vdev->fh_list); 56 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 57 } 58 EXPORT_SYMBOL_GPL(v4l2_fh_add); 59 60 int v4l2_fh_open(struct file *filp) 61 { 62 struct video_device *vdev = video_devdata(filp); 63 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL); 64 65 filp->private_data = fh; 66 if (fh == NULL) 67 return -ENOMEM; 68 v4l2_fh_init(fh, vdev); 69 v4l2_fh_add(fh); 70 return 0; 71 } 72 EXPORT_SYMBOL_GPL(v4l2_fh_open); 73 74 void v4l2_fh_del(struct v4l2_fh *fh) 75 { 76 unsigned long flags; 77 78 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 79 list_del_init(&fh->list); 80 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 81 if (test_bit(V4L2_FL_USE_FH_PRIO, &fh->vdev->flags)) 82 v4l2_prio_close(fh->vdev->prio, fh->prio); 83 } 84 EXPORT_SYMBOL_GPL(v4l2_fh_del); 85 86 void v4l2_fh_exit(struct v4l2_fh *fh) 87 { 88 if (fh->vdev == NULL) 89 return; 90 v4l2_event_unsubscribe_all(fh); 91 fh->vdev = NULL; 92 } 93 EXPORT_SYMBOL_GPL(v4l2_fh_exit); 94 95 int v4l2_fh_release(struct file *filp) 96 { 97 struct v4l2_fh *fh = filp->private_data; 98 99 if (fh) { 100 v4l2_fh_del(fh); 101 v4l2_fh_exit(fh); 102 kfree(fh); 103 } 104 return 0; 105 } 106 EXPORT_SYMBOL_GPL(v4l2_fh_release); 107 108 int v4l2_fh_is_singular(struct v4l2_fh *fh) 109 { 110 unsigned long flags; 111 int is_singular; 112 113 if (fh == NULL || fh->vdev == NULL) 114 return 0; 115 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 116 is_singular = list_is_singular(&fh->list); 117 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 118 return is_singular; 119 } 120 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular); 121