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 20 #include <linux/bitops.h> 21 #include <linux/slab.h> 22 #include <linux/export.h> 23 #include <media/v4l2-dev.h> 24 #include <media/v4l2-fh.h> 25 #include <media/v4l2-event.h> 26 #include <media/v4l2-ioctl.h> 27 #include <media/v4l2-mc.h> 28 29 void v4l2_fh_init(struct v4l2_fh *fh, struct video_device *vdev) 30 { 31 fh->vdev = vdev; 32 /* Inherit from video_device. May be overridden by the driver. */ 33 fh->ctrl_handler = vdev->ctrl_handler; 34 INIT_LIST_HEAD(&fh->list); 35 set_bit(V4L2_FL_USES_V4L2_FH, &fh->vdev->flags); 36 /* 37 * determine_valid_ioctls() does not know if struct v4l2_fh 38 * is used by this driver, but here we do. So enable the 39 * prio ioctls here. 40 */ 41 set_bit(_IOC_NR(VIDIOC_G_PRIORITY), vdev->valid_ioctls); 42 set_bit(_IOC_NR(VIDIOC_S_PRIORITY), vdev->valid_ioctls); 43 fh->prio = V4L2_PRIORITY_UNSET; 44 init_waitqueue_head(&fh->wait); 45 INIT_LIST_HEAD(&fh->available); 46 INIT_LIST_HEAD(&fh->subscribed); 47 fh->sequence = -1; 48 mutex_init(&fh->subscribe_lock); 49 } 50 EXPORT_SYMBOL_GPL(v4l2_fh_init); 51 52 void v4l2_fh_add(struct v4l2_fh *fh) 53 { 54 unsigned long flags; 55 56 v4l2_prio_open(fh->vdev->prio, &fh->prio); 57 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 58 list_add(&fh->list, &fh->vdev->fh_list); 59 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 60 } 61 EXPORT_SYMBOL_GPL(v4l2_fh_add); 62 63 int v4l2_fh_open(struct file *filp) 64 { 65 struct video_device *vdev = video_devdata(filp); 66 struct v4l2_fh *fh = kzalloc(sizeof(*fh), GFP_KERNEL); 67 68 filp->private_data = fh; 69 if (fh == NULL) 70 return -ENOMEM; 71 v4l2_fh_init(fh, vdev); 72 v4l2_fh_add(fh); 73 return 0; 74 } 75 EXPORT_SYMBOL_GPL(v4l2_fh_open); 76 77 void v4l2_fh_del(struct v4l2_fh *fh) 78 { 79 unsigned long flags; 80 81 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 82 list_del_init(&fh->list); 83 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 84 v4l2_prio_close(fh->vdev->prio, fh->prio); 85 } 86 EXPORT_SYMBOL_GPL(v4l2_fh_del); 87 88 void v4l2_fh_exit(struct v4l2_fh *fh) 89 { 90 if (fh->vdev == NULL) 91 return; 92 v4l_disable_media_source(fh->vdev); 93 v4l2_event_unsubscribe_all(fh); 94 mutex_destroy(&fh->subscribe_lock); 95 fh->vdev = NULL; 96 } 97 EXPORT_SYMBOL_GPL(v4l2_fh_exit); 98 99 int v4l2_fh_release(struct file *filp) 100 { 101 struct v4l2_fh *fh = filp->private_data; 102 103 if (fh) { 104 v4l2_fh_del(fh); 105 v4l2_fh_exit(fh); 106 kfree(fh); 107 } 108 return 0; 109 } 110 EXPORT_SYMBOL_GPL(v4l2_fh_release); 111 112 int v4l2_fh_is_singular(struct v4l2_fh *fh) 113 { 114 unsigned long flags; 115 int is_singular; 116 117 if (fh == NULL || fh->vdev == NULL) 118 return 0; 119 spin_lock_irqsave(&fh->vdev->fh_lock, flags); 120 is_singular = list_is_singular(&fh->list); 121 spin_unlock_irqrestore(&fh->vdev->fh_lock, flags); 122 return is_singular; 123 } 124 EXPORT_SYMBOL_GPL(v4l2_fh_is_singular); 125