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The video_device struct has proper ref counting and its release function will be called when the last user releases it. But no such support was available for struct v4l2_device. This made it hard to determine when a USB driver can release the device if it has multiple device nodes. With one device node it is easy of course, since when the device node is released, the whole device can be released. This patch adds refcounting to v4l2_device. When registering device nodes the v4l2_device refcount will be increased, when releasing device nodes it will be decreased. The (optional) release function will be called when the last device node was released. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
194 lines
7.1 KiB
C
194 lines
7.1 KiB
C
/*
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V4L2 device support header.
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Copyright (C) 2008 Hans Verkuil <hverkuil@xs4all.nl>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _V4L2_DEVICE_H
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#define _V4L2_DEVICE_H
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#include <media/media-device.h>
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#include <media/v4l2-subdev.h>
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#include <media/v4l2-dev.h>
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/* Each instance of a V4L2 device should create the v4l2_device struct,
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either stand-alone or embedded in a larger struct.
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It allows easy access to sub-devices (see v4l2-subdev.h) and provides
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basic V4L2 device-level support.
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*/
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#define V4L2_DEVICE_NAME_SIZE (20 + 16)
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struct v4l2_ctrl_handler;
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struct v4l2_device {
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/* dev->driver_data points to this struct.
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Note: dev might be NULL if there is no parent device
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as is the case with e.g. ISA devices. */
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struct device *dev;
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#if defined(CONFIG_MEDIA_CONTROLLER)
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struct media_device *mdev;
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#endif
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/* used to keep track of the registered subdevs */
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struct list_head subdevs;
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/* lock this struct; can be used by the driver as well if this
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struct is embedded into a larger struct. */
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spinlock_t lock;
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/* unique device name, by default the driver name + bus ID */
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char name[V4L2_DEVICE_NAME_SIZE];
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/* notify callback called by some sub-devices. */
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void (*notify)(struct v4l2_subdev *sd,
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unsigned int notification, void *arg);
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/* The control handler. May be NULL. */
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struct v4l2_ctrl_handler *ctrl_handler;
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/* Device's priority state */
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struct v4l2_prio_state prio;
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/* BKL replacement mutex. Temporary solution only. */
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struct mutex ioctl_lock;
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/* Keep track of the references to this struct. */
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struct kref ref;
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/* Release function that is called when the ref count goes to 0. */
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void (*release)(struct v4l2_device *v4l2_dev);
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};
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static inline void v4l2_device_get(struct v4l2_device *v4l2_dev)
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{
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kref_get(&v4l2_dev->ref);
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}
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int v4l2_device_put(struct v4l2_device *v4l2_dev);
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/* Initialize v4l2_dev and make dev->driver_data point to v4l2_dev.
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dev may be NULL in rare cases (ISA devices). In that case you
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must fill in the v4l2_dev->name field before calling this function. */
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int __must_check v4l2_device_register(struct device *dev, struct v4l2_device *v4l2_dev);
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/* Optional function to initialize the name field of struct v4l2_device using
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the driver name and a driver-global atomic_t instance.
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This function will increment the instance counter and returns the instance
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value used in the name.
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Example:
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static atomic_t drv_instance = ATOMIC_INIT(0);
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...
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instance = v4l2_device_set_name(&v4l2_dev, "foo", &drv_instance);
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The first time this is called the name field will be set to foo0 and
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this function returns 0. If the name ends with a digit (e.g. cx18),
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then the name will be set to cx18-0 since cx180 looks really odd. */
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int v4l2_device_set_name(struct v4l2_device *v4l2_dev, const char *basename,
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atomic_t *instance);
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/* Set v4l2_dev->dev to NULL. Call when the USB parent disconnects.
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Since the parent disappears this ensures that v4l2_dev doesn't have an
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invalid parent pointer. */
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void v4l2_device_disconnect(struct v4l2_device *v4l2_dev);
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/* Unregister all sub-devices and any other resources related to v4l2_dev. */
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void v4l2_device_unregister(struct v4l2_device *v4l2_dev);
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/* Register a subdev with a v4l2 device. While registered the subdev module
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is marked as in-use. An error is returned if the module is no longer
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loaded when you attempt to register it. */
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int __must_check v4l2_device_register_subdev(struct v4l2_device *v4l2_dev,
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struct v4l2_subdev *sd);
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/* Unregister a subdev with a v4l2 device. Can also be called if the subdev
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wasn't registered. In that case it will do nothing. */
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void v4l2_device_unregister_subdev(struct v4l2_subdev *sd);
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/* Register device nodes for all subdev of the v4l2 device that are marked with
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* the V4L2_SUBDEV_FL_HAS_DEVNODE flag.
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*/
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int __must_check
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v4l2_device_register_subdev_nodes(struct v4l2_device *v4l2_dev);
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/* Iterate over all subdevs. */
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#define v4l2_device_for_each_subdev(sd, v4l2_dev) \
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list_for_each_entry(sd, &(v4l2_dev)->subdevs, list)
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/* Call the specified callback for all subdevs matching the condition.
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Ignore any errors. Note that you cannot add or delete a subdev
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while walking the subdevs list. */
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#define __v4l2_device_call_subdevs_p(v4l2_dev, sd, cond, o, f, args...) \
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do { \
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list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) \
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if ((cond) && (sd)->ops->o && (sd)->ops->o->f) \
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(sd)->ops->o->f((sd) , ##args); \
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} while (0)
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#define __v4l2_device_call_subdevs(v4l2_dev, cond, o, f, args...) \
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do { \
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struct v4l2_subdev *__sd; \
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\
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__v4l2_device_call_subdevs_p(v4l2_dev, __sd, cond, o, \
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f , ##args); \
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} while (0)
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/* Call the specified callback for all subdevs matching the condition.
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If the callback returns an error other than 0 or -ENOIOCTLCMD, then
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return with that error code. Note that you cannot add or delete a
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subdev while walking the subdevs list. */
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#define __v4l2_device_call_subdevs_until_err_p(v4l2_dev, sd, cond, o, f, args...) \
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({ \
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long __err = 0; \
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\
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list_for_each_entry((sd), &(v4l2_dev)->subdevs, list) { \
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if ((cond) && (sd)->ops->o && (sd)->ops->o->f) \
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__err = (sd)->ops->o->f((sd) , ##args); \
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if (__err && __err != -ENOIOCTLCMD) \
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break; \
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} \
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(__err == -ENOIOCTLCMD) ? 0 : __err; \
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})
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#define __v4l2_device_call_subdevs_until_err(v4l2_dev, cond, o, f, args...) \
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({ \
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struct v4l2_subdev *__sd; \
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__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, cond, o, \
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f, args...); \
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})
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/* Call the specified callback for all subdevs matching grp_id (if 0, then
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match them all). Ignore any errors. Note that you cannot add or delete
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a subdev while walking the subdevs list. */
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#define v4l2_device_call_all(v4l2_dev, grpid, o, f, args...) \
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do { \
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struct v4l2_subdev *__sd; \
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\
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__v4l2_device_call_subdevs_p(v4l2_dev, __sd, \
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!(grpid) || __sd->grp_id == (grpid), o, f , \
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##args); \
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} while (0)
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/* Call the specified callback for all subdevs matching grp_id (if 0, then
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match them all). If the callback returns an error other than 0 or
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-ENOIOCTLCMD, then return with that error code. Note that you cannot
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add or delete a subdev while walking the subdevs list. */
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#define v4l2_device_call_until_err(v4l2_dev, grpid, o, f, args...) \
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({ \
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struct v4l2_subdev *__sd; \
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__v4l2_device_call_subdevs_until_err_p(v4l2_dev, __sd, \
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!(grpid) || __sd->grp_id == (grpid), o, f , \
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##args); \
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})
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#endif
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