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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /drivers/media/mc/mc-devnode.c | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/media/mc/mc-devnode.c')
-rw-r--r-- | drivers/media/mc/mc-devnode.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c new file mode 100644 index 0000000000..680fbb3a93 --- /dev/null +++ b/drivers/media/mc/mc-devnode.c @@ -0,0 +1,328 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Media device node + * + * Copyright (C) 2010 Nokia Corporation + * + * Based on drivers/media/video/v4l2_dev.c code authored by + * Mauro Carvalho Chehab <mchehab@kernel.org> (version 2) + * Alan Cox, <alan@lxorguk.ukuu.org.uk> (version 1) + * + * Contacts: Laurent Pinchart <laurent.pinchart@ideasonboard.com> + * Sakari Ailus <sakari.ailus@iki.fi> + * + * -- + * + * Generic media device node infrastructure to register and unregister + * character devices using a dynamic major number and proper reference + * counting. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/errno.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/kernel.h> +#include <linux/kmod.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/uaccess.h> + +#include <media/media-devnode.h> +#include <media/media-device.h> + +#define MEDIA_NUM_DEVICES 256 +#define MEDIA_NAME "media" + +static dev_t media_dev_t; + +/* + * Active devices + */ +static DEFINE_MUTEX(media_devnode_lock); +static DECLARE_BITMAP(media_devnode_nums, MEDIA_NUM_DEVICES); + +/* Called when the last user of the media device exits. */ +static void media_devnode_release(struct device *cd) +{ + struct media_devnode *devnode = to_media_devnode(cd); + + mutex_lock(&media_devnode_lock); + /* Mark device node number as free */ + clear_bit(devnode->minor, media_devnode_nums); + mutex_unlock(&media_devnode_lock); + + /* Release media_devnode and perform other cleanups as needed. */ + if (devnode->release) + devnode->release(devnode); + + kfree(devnode); + pr_debug("%s: Media Devnode Deallocated\n", __func__); +} + +static struct bus_type media_bus_type = { + .name = MEDIA_NAME, +}; + +static ssize_t media_read(struct file *filp, char __user *buf, + size_t sz, loff_t *off) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + if (!devnode->fops->read) + return -EINVAL; + if (!media_devnode_is_registered(devnode)) + return -EIO; + return devnode->fops->read(filp, buf, sz, off); +} + +static ssize_t media_write(struct file *filp, const char __user *buf, + size_t sz, loff_t *off) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + if (!devnode->fops->write) + return -EINVAL; + if (!media_devnode_is_registered(devnode)) + return -EIO; + return devnode->fops->write(filp, buf, sz, off); +} + +static __poll_t media_poll(struct file *filp, + struct poll_table_struct *poll) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + if (!media_devnode_is_registered(devnode)) + return EPOLLERR | EPOLLHUP; + if (!devnode->fops->poll) + return DEFAULT_POLLMASK; + return devnode->fops->poll(filp, poll); +} + +static long +__media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg, + long (*ioctl_func)(struct file *filp, unsigned int cmd, + unsigned long arg)) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + if (!ioctl_func) + return -ENOTTY; + + if (!media_devnode_is_registered(devnode)) + return -EIO; + + return ioctl_func(filp, cmd, arg); +} + +static long media_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + return __media_ioctl(filp, cmd, arg, devnode->fops->ioctl); +} + +#ifdef CONFIG_COMPAT + +static long media_compat_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + return __media_ioctl(filp, cmd, arg, devnode->fops->compat_ioctl); +} + +#endif /* CONFIG_COMPAT */ + +/* Override for the open function */ +static int media_open(struct inode *inode, struct file *filp) +{ + struct media_devnode *devnode; + int ret; + + /* Check if the media device is available. This needs to be done with + * the media_devnode_lock held to prevent an open/unregister race: + * without the lock, the device could be unregistered and freed between + * the media_devnode_is_registered() and get_device() calls, leading to + * a crash. + */ + mutex_lock(&media_devnode_lock); + devnode = container_of(inode->i_cdev, struct media_devnode, cdev); + /* return ENXIO if the media device has been removed + already or if it is not registered anymore. */ + if (!media_devnode_is_registered(devnode)) { + mutex_unlock(&media_devnode_lock); + return -ENXIO; + } + /* and increase the device refcount */ + get_device(&devnode->dev); + mutex_unlock(&media_devnode_lock); + + filp->private_data = devnode; + + if (devnode->fops->open) { + ret = devnode->fops->open(filp); + if (ret) { + put_device(&devnode->dev); + filp->private_data = NULL; + return ret; + } + } + + return 0; +} + +/* Override for the release function */ +static int media_release(struct inode *inode, struct file *filp) +{ + struct media_devnode *devnode = media_devnode_data(filp); + + if (devnode->fops->release) + devnode->fops->release(filp); + + filp->private_data = NULL; + + /* decrease the refcount unconditionally since the release() + return value is ignored. */ + put_device(&devnode->dev); + + pr_debug("%s: Media Release\n", __func__); + return 0; +} + +static const struct file_operations media_devnode_fops = { + .owner = THIS_MODULE, + .read = media_read, + .write = media_write, + .open = media_open, + .unlocked_ioctl = media_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = media_compat_ioctl, +#endif /* CONFIG_COMPAT */ + .release = media_release, + .poll = media_poll, + .llseek = no_llseek, +}; + +int __must_check media_devnode_register(struct media_device *mdev, + struct media_devnode *devnode, + struct module *owner) +{ + int minor; + int ret; + + /* Part 1: Find a free minor number */ + mutex_lock(&media_devnode_lock); + minor = find_first_zero_bit(media_devnode_nums, MEDIA_NUM_DEVICES); + if (minor == MEDIA_NUM_DEVICES) { + mutex_unlock(&media_devnode_lock); + pr_err("could not get a free minor\n"); + kfree(devnode); + return -ENFILE; + } + + set_bit(minor, media_devnode_nums); + mutex_unlock(&media_devnode_lock); + + devnode->minor = minor; + devnode->media_dev = mdev; + + /* Part 1: Initialize dev now to use dev.kobj for cdev.kobj.parent */ + devnode->dev.bus = &media_bus_type; + devnode->dev.devt = MKDEV(MAJOR(media_dev_t), devnode->minor); + devnode->dev.release = media_devnode_release; + if (devnode->parent) + devnode->dev.parent = devnode->parent; + dev_set_name(&devnode->dev, "media%d", devnode->minor); + device_initialize(&devnode->dev); + + /* Part 2: Initialize the character device */ + cdev_init(&devnode->cdev, &media_devnode_fops); + devnode->cdev.owner = owner; + kobject_set_name(&devnode->cdev.kobj, "media%d", devnode->minor); + + /* Part 3: Add the media and char device */ + ret = cdev_device_add(&devnode->cdev, &devnode->dev); + if (ret < 0) { + pr_err("%s: cdev_device_add failed\n", __func__); + goto cdev_add_error; + } + + /* Part 4: Activate this minor. The char device can now be used. */ + set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); + + return 0; + +cdev_add_error: + mutex_lock(&media_devnode_lock); + clear_bit(devnode->minor, media_devnode_nums); + devnode->media_dev = NULL; + mutex_unlock(&media_devnode_lock); + + put_device(&devnode->dev); + return ret; +} + +void media_devnode_unregister_prepare(struct media_devnode *devnode) +{ + /* Check if devnode was ever registered at all */ + if (!media_devnode_is_registered(devnode)) + return; + + mutex_lock(&media_devnode_lock); + clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); + mutex_unlock(&media_devnode_lock); +} + +void media_devnode_unregister(struct media_devnode *devnode) +{ + mutex_lock(&media_devnode_lock); + /* Delete the cdev on this minor as well */ + cdev_device_del(&devnode->cdev, &devnode->dev); + devnode->media_dev = NULL; + mutex_unlock(&media_devnode_lock); + + put_device(&devnode->dev); +} + +/* + * Initialise media for linux + */ +static int __init media_devnode_init(void) +{ + int ret; + + pr_info("Linux media interface: v0.10\n"); + ret = alloc_chrdev_region(&media_dev_t, 0, MEDIA_NUM_DEVICES, + MEDIA_NAME); + if (ret < 0) { + pr_warn("unable to allocate major\n"); + return ret; + } + + ret = bus_register(&media_bus_type); + if (ret < 0) { + unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); + pr_warn("bus_register failed\n"); + return -EIO; + } + + return 0; +} + +static void __exit media_devnode_exit(void) +{ + bus_unregister(&media_bus_type); + unregister_chrdev_region(media_dev_t, MEDIA_NUM_DEVICES); +} + +subsys_initcall(media_devnode_init); +module_exit(media_devnode_exit) + +MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>"); +MODULE_DESCRIPTION("Device node registration for media drivers"); +MODULE_LICENSE("GPL"); |