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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-23 13:28:57 -0700 |
| commit | 4352b8aee98005853aa63f57d6377282de17a33f (patch) | |
| tree | 27614d7a9ef05c32d089004e104364ce42324837 /drivers/media/mc/mc-devnode.c | |
| download | linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip | |
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni:
"A new driver this cycle, for the AMD AXI I3C controller.
There are also new features such as IBI wakeup support, SETAASA device
discovery and ACPI support for the the DAA methods, meaning we can now
communicate with the SPD devices on DDR5 modules.
New driver:
- AMD AXI I3C master controller
Subsystem:
- I3C Common Command Code (CCC) handling improvements, especially
around GET CCCs
- SETAASA device discovery support
- ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
well as I2C devices on I3C bus
- IBI-based wakeup support
Drivers:
- dw: SETAASA support
- mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
controller support, PIO queue management support for HCI v1.2
- renesas: improve suspend to RAM support, add runtime PM support"
* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
i3c: dw: reduce do_daa time if there's no client
i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
i3c: dw: rename "pclk" to "apb" to match dt-binding
i3c: dw: make struct dw_i3c_cmd smaller
i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
i3c: renesas: Don't register devices when ENTDAA times out
i3c: master: dw-i3c-master: fix OD timing for first broadcast
i3c: mipi-i3c-hci: Advertise IBI wakeup capability
i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
i3c: master: Reject IBI requests from non-IBI-capable devices
i3c: master: Add helper to query bus wakeup requirements
i3c: master: Report wakeup events for IBIs
i3c: master: Support IBI-based wakeup capability
i3c: master: Fix potential UAF in i3c_device_match()
i3c: master: Fix potential UAF in i3c_device_uevent()
i3c: Make dev->desc locking assumptions explicit
i3c: master: Fix use-after-free of master->this
...
Diffstat (limited to 'drivers/media/mc/mc-devnode.c')
| -rw-r--r-- | drivers/media/mc/mc-devnode.c | 326 |
1 files changed, 326 insertions, 0 deletions
diff --git a/drivers/media/mc/mc-devnode.c b/drivers/media/mc/mc-devnode.c new file mode 100644 index 000000000..51260a7d6 --- /dev/null +++ b/drivers/media/mc/mc-devnode.c @@ -0,0 +1,326 @@ +// 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); + +/* debugfs */ +struct dentry *media_debugfs_root; + +/* 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); + + /* 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 const 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); + + 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, +}; + +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); + dev_set_drvdata(&devnode->dev, mdev); + 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 */ + set_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); + ret = cdev_device_add(&devnode->cdev, &devnode->dev); + if (ret < 0) { + clear_bit(MEDIA_FLAG_REGISTERED, &devnode->flags); + pr_err("%s: cdev_device_add failed\n", __func__); + goto cdev_add_error; + } + + 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; + clear_bit(devnode->minor, media_devnode_nums); + 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) +{ + debugfs_remove_recursive(media_debugfs_root); + 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"); |
