mirror of
https://github.com/torvalds/linux.git
synced 2024-11-22 20:22:09 +00:00
c612e54fca
It is really weird that the media controller sources are all top-level in drivers/media. It is a bit of a left-over from long ago when most media sources were all at the top-level. At some point we reorganized the directory structure, but the media-*.c sources where never moved to their own directory. So create a new mc directory and move all sources there. Also rename the prefix from media- to mc-. Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
136 lines
3.5 KiB
C
136 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* media-dev-allocator.c - Media Controller Device Allocator API
|
|
*
|
|
* Copyright (c) 2019 Shuah Khan <shuah@kernel.org>
|
|
*
|
|
* Credits: Suggested by Laurent Pinchart <laurent.pinchart@ideasonboard.com>
|
|
*/
|
|
|
|
/*
|
|
* This file adds a global refcounted Media Controller Device Instance API.
|
|
* A system wide global media device list is managed and each media device
|
|
* includes a kref count. The last put on the media device releases the media
|
|
* device instance.
|
|
*
|
|
*/
|
|
|
|
#include <linux/kref.h>
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/usb.h>
|
|
|
|
#include <media/media-device.h>
|
|
#include <media/media-dev-allocator.h>
|
|
|
|
static LIST_HEAD(media_device_list);
|
|
static DEFINE_MUTEX(media_device_lock);
|
|
|
|
struct media_device_instance {
|
|
struct media_device mdev;
|
|
struct module *owner;
|
|
struct list_head list;
|
|
struct kref refcount;
|
|
};
|
|
|
|
static inline struct media_device_instance *
|
|
to_media_device_instance(struct media_device *mdev)
|
|
{
|
|
return container_of(mdev, struct media_device_instance, mdev);
|
|
}
|
|
|
|
static void media_device_instance_release(struct kref *kref)
|
|
{
|
|
struct media_device_instance *mdi =
|
|
container_of(kref, struct media_device_instance, refcount);
|
|
|
|
dev_dbg(mdi->mdev.dev, "%s: releasing Media Device\n", __func__);
|
|
|
|
mutex_lock(&media_device_lock);
|
|
|
|
media_device_unregister(&mdi->mdev);
|
|
media_device_cleanup(&mdi->mdev);
|
|
|
|
list_del(&mdi->list);
|
|
mutex_unlock(&media_device_lock);
|
|
|
|
kfree(mdi);
|
|
}
|
|
|
|
/* Callers should hold media_device_lock when calling this function */
|
|
static struct media_device *__media_device_get(struct device *dev,
|
|
const char *module_name,
|
|
struct module *owner)
|
|
{
|
|
struct media_device_instance *mdi;
|
|
|
|
list_for_each_entry(mdi, &media_device_list, list) {
|
|
if (mdi->mdev.dev != dev)
|
|
continue;
|
|
|
|
kref_get(&mdi->refcount);
|
|
|
|
/* get module reference for the media_device owner */
|
|
if (owner != mdi->owner && !try_module_get(mdi->owner))
|
|
dev_err(dev,
|
|
"%s: module %s get owner reference error\n",
|
|
__func__, module_name);
|
|
else
|
|
dev_dbg(dev, "%s: module %s got owner reference\n",
|
|
__func__, module_name);
|
|
return &mdi->mdev;
|
|
}
|
|
|
|
mdi = kzalloc(sizeof(*mdi), GFP_KERNEL);
|
|
if (!mdi)
|
|
return NULL;
|
|
|
|
mdi->owner = owner;
|
|
kref_init(&mdi->refcount);
|
|
list_add_tail(&mdi->list, &media_device_list);
|
|
|
|
dev_dbg(dev, "%s: Allocated media device for owner %s\n",
|
|
__func__, module_name);
|
|
return &mdi->mdev;
|
|
}
|
|
|
|
struct media_device *media_device_usb_allocate(struct usb_device *udev,
|
|
const char *module_name,
|
|
struct module *owner)
|
|
{
|
|
struct media_device *mdev;
|
|
|
|
mutex_lock(&media_device_lock);
|
|
mdev = __media_device_get(&udev->dev, module_name, owner);
|
|
if (!mdev) {
|
|
mutex_unlock(&media_device_lock);
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
|
|
/* check if media device is already initialized */
|
|
if (!mdev->dev)
|
|
__media_device_usb_init(mdev, udev, udev->product,
|
|
module_name);
|
|
mutex_unlock(&media_device_lock);
|
|
return mdev;
|
|
}
|
|
EXPORT_SYMBOL_GPL(media_device_usb_allocate);
|
|
|
|
void media_device_delete(struct media_device *mdev, const char *module_name,
|
|
struct module *owner)
|
|
{
|
|
struct media_device_instance *mdi = to_media_device_instance(mdev);
|
|
|
|
mutex_lock(&media_device_lock);
|
|
/* put module reference for the media_device owner */
|
|
if (mdi->owner != owner) {
|
|
module_put(mdi->owner);
|
|
dev_dbg(mdi->mdev.dev,
|
|
"%s: module %s put owner module reference\n",
|
|
__func__, module_name);
|
|
}
|
|
mutex_unlock(&media_device_lock);
|
|
kref_put(&mdi->refcount, media_device_instance_release);
|
|
}
|
|
EXPORT_SYMBOL_GPL(media_device_delete);
|