[mirror_ubuntu-jammy-kernel.git] / drivers / media / v4l2-core / v4l2-async.c

/*
 * V4L2 asynchronous subdevice registration API
 *
 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/list.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <media/v4l2-async.h>
#include <media/v4l2-device.h>
#include <media/v4l2-fwnode.h>
#include <media/v4l2-subdev.h>

static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
					  struct v4l2_subdev *subdev,
					  struct v4l2_async_subdev *asd)
{
	if (!n->ops || !n->ops->bound)
		return 0;

	return n->ops->bound(n, subdev, asd);
}

static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
					    struct v4l2_subdev *subdev,
					    struct v4l2_async_subdev *asd)
{
	if (!n->ops || !n->ops->unbind)
		return;

	n->ops->unbind(n, subdev, asd);
}

static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
{
	if (!n->ops || !n->ops->complete)
		return 0;

	return n->ops->complete(n);
}

static bool match_i2c(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
#if IS_ENABLED(CONFIG_I2C)
	struct i2c_client *client = i2c_verify_client(sd->dev);
	return client &&
		asd->match.i2c.adapter_id == client->adapter->nr &&
		asd->match.i2c.address == client->addr;
#else
	return false;
#endif
}

static bool match_devname(struct v4l2_subdev *sd,
			  struct v4l2_async_subdev *asd)
{
	return !strcmp(asd->match.device_name.name, dev_name(sd->dev));
}

static bool match_fwnode(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
	return sd->fwnode == asd->match.fwnode.fwnode;
}

static bool match_custom(struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
{
	if (!asd->match.custom.match)
		/* Match always */
		return true;

	return asd->match.custom.match(sd->dev, asd);
}

static LIST_HEAD(subdev_list);
static LIST_HEAD(notifier_list);
static DEFINE_MUTEX(list_lock);

static struct v4l2_async_subdev *v4l2_async_find_match(
	struct v4l2_async_notifier *notifier, struct v4l2_subdev *sd)
{
	bool (*match)(struct v4l2_subdev *, struct v4l2_async_subdev *);
	struct v4l2_async_subdev *asd;

	list_for_each_entry(asd, &notifier->waiting, list) {
		/* bus_type has been verified valid before */
		switch (asd->match_type) {
		case V4L2_ASYNC_MATCH_CUSTOM:
			match = match_custom;
			break;
		case V4L2_ASYNC_MATCH_DEVNAME:
			match = match_devname;
			break;
		case V4L2_ASYNC_MATCH_I2C:
			match = match_i2c;
			break;
		case V4L2_ASYNC_MATCH_FWNODE:
			match = match_fwnode;
			break;
		default:
			/* Cannot happen, unless someone breaks us */
			WARN_ON(true);
			return NULL;
		}

		/* match cannot be NULL here */
		if (match(sd, asd))
			return asd;
	}

	return NULL;
}

/* Find the sub-device notifier registered by a sub-device driver. */
static struct v4l2_async_notifier *v4l2_async_find_subdev_notifier(
	struct v4l2_subdev *sd)
{
	struct v4l2_async_notifier *n;

	list_for_each_entry(n, &notifier_list, list)
		if (n->sd == sd)
			return n;

	return NULL;
}

/* Get v4l2_device related to the notifier if one can be found. */
static struct v4l2_device *v4l2_async_notifier_find_v4l2_dev(
	struct v4l2_async_notifier *notifier)
{
	while (notifier->parent)
		notifier = notifier->parent;

	return notifier->v4l2_dev;
}

/*
 * Return true if all child sub-device notifiers are complete, false otherwise.
 */
static bool v4l2_async_notifier_can_complete(
	struct v4l2_async_notifier *notifier)
{
	struct v4l2_subdev *sd;

	if (!list_empty(&notifier->waiting))
		return false;

	list_for_each_entry(sd, &notifier->done, async_list) {
		struct v4l2_async_notifier *subdev_notifier =
			v4l2_async_find_subdev_notifier(sd);

		if (subdev_notifier &&
		    !v4l2_async_notifier_can_complete(subdev_notifier))
			return false;
	}

	return true;
}

/*
 * Complete the master notifier if possible. This is done when all async
 * sub-devices have been bound; v4l2_device is also available then.
 */
static int v4l2_async_notifier_try_complete(
	struct v4l2_async_notifier *notifier)
{
	/* Quick check whether there are still more sub-devices here. */
	if (!list_empty(&notifier->waiting))
		return 0;

	/* Check the entire notifier tree; find the root notifier first. */
	while (notifier->parent)
		notifier = notifier->parent;

	/* This is root if it has v4l2_dev. */
	if (!notifier->v4l2_dev)
		return 0;

	/* Is everything ready? */
	if (!v4l2_async_notifier_can_complete(notifier))
		return 0;

	return v4l2_async_notifier_call_complete(notifier);
}

static int v4l2_async_notifier_try_all_subdevs(
	struct v4l2_async_notifier *notifier);

static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
				   struct v4l2_device *v4l2_dev,
				   struct v4l2_subdev *sd,
				   struct v4l2_async_subdev *asd)
{
	struct v4l2_async_notifier *subdev_notifier;
	int ret;

	ret = v4l2_device_register_subdev(v4l2_dev, sd);
	if (ret < 0)
		return ret;

	ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
	if (ret < 0) {
		v4l2_device_unregister_subdev(sd);
		return ret;
	}

	/* Remove from the waiting list */
	list_del(&asd->list);
	sd->asd = asd;
	sd->notifier = notifier;

	/* Move from the global subdevice list to notifier's done */
	list_move(&sd->async_list, &notifier->done);

	/*
	 * See if the sub-device has a notifier. If not, return here.
	 */
	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
	if (!subdev_notifier || subdev_notifier->parent)
		return 0;

	/*
	 * Proceed with checking for the sub-device notifier's async
	 * sub-devices, and return the result. The error will be handled by the
	 * caller.
	 */
	subdev_notifier->parent = notifier;

	return v4l2_async_notifier_try_all_subdevs(subdev_notifier);
}

/* Test all async sub-devices in a notifier for a match. */
static int v4l2_async_notifier_try_all_subdevs(
	struct v4l2_async_notifier *notifier)
{
	struct v4l2_device *v4l2_dev =
		v4l2_async_notifier_find_v4l2_dev(notifier);
	struct v4l2_subdev *sd;

	if (!v4l2_dev)
		return 0;

again:
	list_for_each_entry(sd, &subdev_list, async_list) {
		struct v4l2_async_subdev *asd;
		int ret;

		asd = v4l2_async_find_match(notifier, sd);
		if (!asd)
			continue;

		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
		if (ret < 0)
			return ret;

		/*
		 * v4l2_async_match_notify() may lead to registering a
		 * new notifier and thus changing the async subdevs
		 * list. In order to proceed safely from here, restart
		 * parsing the list from the beginning.
		 */
		goto again;
	}

	return 0;
}

static void v4l2_async_cleanup(struct v4l2_subdev *sd)
{
	v4l2_device_unregister_subdev(sd);
	/* Subdevice driver will reprobe and put the subdev back onto the list */
	list_del_init(&sd->async_list);
	sd->asd = NULL;
}

/* Unbind all sub-devices in the notifier tree. */
static void v4l2_async_notifier_unbind_all_subdevs(
	struct v4l2_async_notifier *notifier)
{
	struct v4l2_subdev *sd, *tmp;

	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
		struct v4l2_async_notifier *subdev_notifier =
			v4l2_async_find_subdev_notifier(sd);

		if (subdev_notifier)
			v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);

		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
		v4l2_async_cleanup(sd);

		list_move(&sd->async_list, &subdev_list);
	}

	notifier->parent = NULL;
}

/* See if an fwnode can be found in a notifier's lists. */
static bool __v4l2_async_notifier_fwnode_has_async_subdev(
	struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode)
{
	struct v4l2_async_subdev *asd;
	struct v4l2_subdev *sd;

	list_for_each_entry(asd, &notifier->waiting, list) {
		if (asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
			continue;

		if (asd->match.fwnode.fwnode == fwnode)
			return true;
	}

	list_for_each_entry(sd, &notifier->done, async_list) {
		if (WARN_ON(!sd->asd))
			continue;

		if (sd->asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
			continue;

		if (sd->asd->match.fwnode.fwnode == fwnode)
			return true;
	}

	return false;
}

/*
 * Find out whether an async sub-device was set up for an fwnode already or
 * whether it exists in a given notifier before @this_index.
 */
static bool v4l2_async_notifier_fwnode_has_async_subdev(
	struct v4l2_async_notifier *notifier, struct fwnode_handle *fwnode,
	unsigned int this_index)
{
	unsigned int j;

	lockdep_assert_held(&list_lock);

	/* Check that an fwnode is not being added more than once. */
	for (j = 0; j < this_index; j++) {
		struct v4l2_async_subdev *asd = notifier->subdevs[this_index];
		struct v4l2_async_subdev *other_asd = notifier->subdevs[j];

		if (other_asd->match_type == V4L2_ASYNC_MATCH_FWNODE &&
		    asd->match.fwnode.fwnode ==
		    other_asd->match.fwnode.fwnode)
			return true;
	}

	/* Check than an fwnode did not exist in other notifiers. */
	list_for_each_entry(notifier, &notifier_list, list)
		if (__v4l2_async_notifier_fwnode_has_async_subdev(
			    notifier, fwnode))
			return true;

	return false;
}

static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
{
	struct device *dev =
		notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
	struct v4l2_async_subdev *asd;
	int ret;
	int i;

	if (notifier->num_subdevs > V4L2_MAX_SUBDEVS)
		return -EINVAL;

	INIT_LIST_HEAD(&notifier->waiting);
	INIT_LIST_HEAD(&notifier->done);

	mutex_lock(&list_lock);

	for (i = 0; i < notifier->num_subdevs; i++) {
		asd = notifier->subdevs[i];

		switch (asd->match_type) {
		case V4L2_ASYNC_MATCH_CUSTOM:
		case V4L2_ASYNC_MATCH_DEVNAME:
		case V4L2_ASYNC_MATCH_I2C:
			break;
		case V4L2_ASYNC_MATCH_FWNODE:
			if (v4l2_async_notifier_fwnode_has_async_subdev(
				    notifier, asd->match.fwnode.fwnode, i)) {
				dev_err(dev,
					"fwnode has already been registered or in notifier's subdev list\n");
				ret = -EEXIST;
				goto err_unlock;
			}
			break;
		default:
			dev_err(dev, "Invalid match type %u on %p\n",
				asd->match_type, asd);
			ret = -EINVAL;
			goto err_unlock;
		}
		list_add_tail(&asd->list, &notifier->waiting);
	}

	ret = v4l2_async_notifier_try_all_subdevs(notifier);
	if (ret < 0)
		goto err_unbind;

	ret = v4l2_async_notifier_try_complete(notifier);
	if (ret < 0)
		goto err_unbind;

	/* Keep also completed notifiers on the list */
	list_add(&notifier->list, &notifier_list);

	mutex_unlock(&list_lock);

	return 0;

err_unbind:
	/*
	 * On failure, unbind all sub-devices registered through this notifier.
	 */
	v4l2_async_notifier_unbind_all_subdevs(notifier);

err_unlock:
	mutex_unlock(&list_lock);

	return ret;
}

int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
				 struct v4l2_async_notifier *notifier)
{
	int ret;

	if (WARN_ON(!v4l2_dev || notifier->sd))
		return -EINVAL;

	notifier->v4l2_dev = v4l2_dev;

	ret = __v4l2_async_notifier_register(notifier);
	if (ret)
		notifier->v4l2_dev = NULL;

	return ret;
}
EXPORT_SYMBOL(v4l2_async_notifier_register);

int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
					struct v4l2_async_notifier *notifier)
{
	int ret;

	if (WARN_ON(!sd || notifier->v4l2_dev))
		return -EINVAL;

	notifier->sd = sd;

	ret = __v4l2_async_notifier_register(notifier);
	if (ret)
		notifier->sd = NULL;

	return ret;
}
EXPORT_SYMBOL(v4l2_async_subdev_notifier_register);

static void __v4l2_async_notifier_unregister(
	struct v4l2_async_notifier *notifier)
{
	if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
		return;

	v4l2_async_notifier_unbind_all_subdevs(notifier);

	notifier->sd = NULL;
	notifier->v4l2_dev = NULL;

	list_del(&notifier->list);
}

void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
{
	mutex_lock(&list_lock);

	__v4l2_async_notifier_unregister(notifier);

	mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_notifier_unregister);

void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
{
	unsigned int i;

	if (!notifier || !notifier->max_subdevs)
		return;

	for (i = 0; i < notifier->num_subdevs; i++) {
		struct v4l2_async_subdev *asd = notifier->subdevs[i];

		switch (asd->match_type) {
		case V4L2_ASYNC_MATCH_FWNODE:
			fwnode_handle_put(asd->match.fwnode.fwnode);
			break;
		default:
			WARN_ON_ONCE(true);
			break;
		}

		kfree(asd);
	}

	notifier->max_subdevs = 0;
	notifier->num_subdevs = 0;

	kvfree(notifier->subdevs);
	notifier->subdevs = NULL;
}
EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);

int v4l2_async_register_subdev(struct v4l2_subdev *sd)
{
	struct v4l2_async_notifier *subdev_notifier;
	struct v4l2_async_notifier *notifier;
	int ret;

	/*
	 * No reference taken. The reference is held by the device
	 * (struct v4l2_subdev.dev), and async sub-device does not
	 * exist independently of the device at any point of time.
	 */
	if (!sd->fwnode && sd->dev)
		sd->fwnode = dev_fwnode(sd->dev);

	mutex_lock(&list_lock);

	INIT_LIST_HEAD(&sd->async_list);

	list_for_each_entry(notifier, &notifier_list, list) {
		struct v4l2_device *v4l2_dev =
			v4l2_async_notifier_find_v4l2_dev(notifier);
		struct v4l2_async_subdev *asd;

		if (!v4l2_dev)
			continue;

		asd = v4l2_async_find_match(notifier, sd);
		if (!asd)
			continue;

		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
		if (ret)
			goto err_unbind;

		ret = v4l2_async_notifier_try_complete(notifier);
		if (ret)
			goto err_unbind;

		goto out_unlock;
	}

	/* None matched, wait for hot-plugging */
	list_add(&sd->async_list, &subdev_list);

out_unlock:
	mutex_unlock(&list_lock);

	return 0;

err_unbind:
	/*
	 * Complete failed. Unbind the sub-devices bound through registering
	 * this async sub-device.
	 */
	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
	if (subdev_notifier)
		v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);

	if (sd->asd)
		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
	v4l2_async_cleanup(sd);

	mutex_unlock(&list_lock);

	return ret;
}
EXPORT_SYMBOL(v4l2_async_register_subdev);

void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
{
	mutex_lock(&list_lock);

	__v4l2_async_notifier_unregister(sd->subdev_notifier);
	v4l2_async_notifier_cleanup(sd->subdev_notifier);
	kfree(sd->subdev_notifier);
	sd->subdev_notifier = NULL;

	if (sd->asd) {
		struct v4l2_async_notifier *notifier = sd->notifier;

		list_add(&sd->asd->list, &notifier->waiting);

		v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
	}

	v4l2_async_cleanup(sd);

	mutex_unlock(&list_lock);
}
EXPORT_SYMBOL(v4l2_async_unregister_subdev);
Commit	Line	Data
e9e31049 GL	1	/*
	2	* V4L2 asynchronous subdevice registration API
	3	*
	4	* Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/device.h>
	12	#include <linux/err.h>
	13	#include <linux/i2c.h>
	14	#include <linux/list.h>
758d90e1	15	#include <linux/mm.h>
e9e31049 GL	16	#include <linux/module.h>
e9e31049 GL	17	#include <linux/mutex.h>
ecdf0cfe	18	#include <linux/of.h>
e9e31049 GL	19	#include <linux/platform_device.h>
	20	#include <linux/slab.h>
	21	#include <linux/types.h>
	22
	23	#include <media/v4l2-async.h>
	24	#include <media/v4l2-device.h>
9ca46531	25	#include <media/v4l2-fwnode.h>
e9e31049 GL	26	#include <media/v4l2-subdev.h>
e9e31049 GL	27
ddddc18b SA	28	static int v4l2_async_notifier_call_bound(struct v4l2_async_notifier *n,
	29	struct v4l2_subdev *subdev,
	30	struct v4l2_async_subdev *asd)
	31	{
	32	if (!n->ops \|\| !n->ops->bound)
	33	return 0;
	34
	35	return n->ops->bound(n, subdev, asd);
	36	}
	37
	38	static void v4l2_async_notifier_call_unbind(struct v4l2_async_notifier *n,
	39	struct v4l2_subdev *subdev,
	40	struct v4l2_async_subdev *asd)
	41	{
	42	if (!n->ops \|\| !n->ops->unbind)
	43	return;
	44
	45	n->ops->unbind(n, subdev, asd);
	46	}
	47
	48	static int v4l2_async_notifier_call_complete(struct v4l2_async_notifier *n)
	49	{
	50	if (!n->ops \|\| !n->ops->complete)
	51	return 0;
	52
	53	return n->ops->complete(n);
	54	}
	55
86217651	56	static bool match_i2c(struct v4l2_subdev sd, struct v4l2_async_subdev asd)
e9e31049	57	{
fe05e141	58	#if IS_ENABLED(CONFIG_I2C)
86217651	59	struct i2c_client *client = i2c_verify_client(sd->dev);
e9e31049	60	return client &&
e9e31049 GL	61	asd->match.i2c.adapter_id == client->adapter->nr &&
e9e31049 GL	62	asd->match.i2c.address == client->addr;
fe05e141 GL	63	#else
	64	return false;
	65	#endif
e9e31049 GL	66	}
e9e31049 GL	67
86217651 SA	68	static bool match_devname(struct v4l2_subdev *sd,
86217651 SA	69	struct v4l2_async_subdev *asd)
e9e31049	70	{
86217651	71	return !strcmp(asd->match.device_name.name, dev_name(sd->dev));
e9e31049 GL	72	}
e9e31049 GL	73
ecdf0cfe SA	74	static bool match_fwnode(struct v4l2_subdev sd, struct v4l2_async_subdev asd)
ecdf0cfe SA	75	{
12f92866	76	return sd->fwnode == asd->match.fwnode.fwnode;
ecdf0cfe SA	77	}
ecdf0cfe SA	78
86217651 SA	79	static bool match_custom(struct v4l2_subdev sd, struct v4l2_async_subdev asd)
	80	{
	81	if (!asd->match.custom.match)
	82	/* Match always */
	83	return true;
	84
	85	return asd->match.custom.match(sd->dev, asd);
e7359f8e SN	86	}
e7359f8e SN	87
e9e31049 GL	88	static LIST_HEAD(subdev_list);
	89	static LIST_HEAD(notifier_list);
	90	static DEFINE_MUTEX(list_lock);
	91
c8114d90 SA	92	static struct v4l2_async_subdev *v4l2_async_find_match(
c8114d90 SA	93	struct v4l2_async_notifier notifier, struct v4l2_subdev sd)
e9e31049	94	{
86217651	95	bool (match)(struct v4l2_subdev , struct v4l2_async_subdev *);
e9e31049	96	struct v4l2_async_subdev *asd;
e9e31049 GL	97
	98	list_for_each_entry(asd, &notifier->waiting, list) {
	99	/* bus_type has been verified valid before */
cfca7644 SN	100	switch (asd->match_type) {
cfca7644 SN	101	case V4L2_ASYNC_MATCH_CUSTOM:
86217651	102	match = match_custom;
e9e31049	103	break;
cfca7644 SN	104	case V4L2_ASYNC_MATCH_DEVNAME:
cfca7644 SN	105	match = match_devname;
e9e31049	106	break;
cfca7644	107	case V4L2_ASYNC_MATCH_I2C:
e9e31049 GL	108	match = match_i2c;
e9e31049 GL	109	break;
ecdf0cfe SA	110	case V4L2_ASYNC_MATCH_FWNODE:
	111	match = match_fwnode;
	112	break;
e9e31049 GL	113	default:
	114	/* Cannot happen, unless someone breaks us */
	115	WARN_ON(true);
	116	return NULL;
	117	}
	118
	119	/* match cannot be NULL here */
86217651	120	if (match(sd, asd))
e9e31049 GL	121	return asd;
	122	}
	123
	124	return NULL;
	125	}
	126
2cab00bb SA	127	/* Find the sub-device notifier registered by a sub-device driver. */
	128	static struct v4l2_async_notifier *v4l2_async_find_subdev_notifier(
	129	struct v4l2_subdev *sd)
	130	{
	131	struct v4l2_async_notifier *n;
	132
	133	list_for_each_entry(n, &notifier_list, list)
	134	if (n->sd == sd)
	135	return n;
	136
	137	return NULL;
	138	}
	139
	140	/* Get v4l2_device related to the notifier if one can be found. */
	141	static struct v4l2_device *v4l2_async_notifier_find_v4l2_dev(
	142	struct v4l2_async_notifier *notifier)
	143	{
	144	while (notifier->parent)
	145	notifier = notifier->parent;
	146
	147	return notifier->v4l2_dev;
	148	}
	149
	150	/*
	151	* Return true if all child sub-device notifiers are complete, false otherwise.
	152	*/
	153	static bool v4l2_async_notifier_can_complete(
	154	struct v4l2_async_notifier *notifier)
	155	{
	156	struct v4l2_subdev *sd;
	157
	158	if (!list_empty(&notifier->waiting))
	159	return false;
	160
	161	list_for_each_entry(sd, &notifier->done, async_list) {
	162	struct v4l2_async_notifier *subdev_notifier =
	163	v4l2_async_find_subdev_notifier(sd);
	164
	165	if (subdev_notifier &&
	166	!v4l2_async_notifier_can_complete(subdev_notifier))
	167	return false;
	168	}
	169
	170	return true;
	171	}
	172
	173	/*
	174	* Complete the master notifier if possible. This is done when all async
	175	* sub-devices have been bound; v4l2_device is also available then.
	176	*/
	177	static int v4l2_async_notifier_try_complete(
	178	struct v4l2_async_notifier *notifier)
	179	{
	180	/* Quick check whether there are still more sub-devices here. */
	181	if (!list_empty(&notifier->waiting))
	182	return 0;
	183
	184	/* Check the entire notifier tree; find the root notifier first. */
	185	while (notifier->parent)
	186	notifier = notifier->parent;
	187
	188	/* This is root if it has v4l2_dev. */
	189	if (!notifier->v4l2_dev)
	190	return 0;
191
192	/* Is everything ready? */
193	if (!v4l2_async_notifier_can_complete(notifier))
194	return 0;
195
196	return v4l2_async_notifier_call_complete(notifier);
197	}
198
199	static int v4l2_async_notifier_try_all_subdevs(
200	struct v4l2_async_notifier *notifier);
201
c8114d90	202	static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
a3620cb4	203	struct v4l2_device *v4l2_dev,
c8114d90 SA	204	struct v4l2_subdev *sd,
c8114d90 SA	205	struct v4l2_async_subdev *asd)
e9e31049	206	{
2cab00bb	207	struct v4l2_async_notifier *subdev_notifier;
e9e31049 GL	208	int ret;
e9e31049 GL	209
a3620cb4	210	ret = v4l2_device_register_subdev(v4l2_dev, sd);
ddddc18b SA	211	if (ret < 0)
ddddc18b SA	212	return ret;
e9e31049	213
24def9b5	214	ret = v4l2_async_notifier_call_bound(notifier, sd, asd);
e9e31049	215	if (ret < 0) {
24def9b5	216	v4l2_device_unregister_subdev(sd);
e9e31049 GL	217	return ret;
	218	}
	219
47b037a0 TT	220	/* Remove from the waiting list */
	221	list_del(&asd->list);
	222	sd->asd = asd;
	223	sd->notifier = notifier;
	224
	225	/* Move from the global subdevice list to notifier's done */
	226	list_move(&sd->async_list, &notifier->done);
	227
2cab00bb SA	228	/*
	229	* See if the sub-device has a notifier. If not, return here.
	230	*/
	231	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
	232	if (!subdev_notifier \|\| subdev_notifier->parent)
	233	return 0;
	234
	235	/*
	236	* Proceed with checking for the sub-device notifier's async
	237	* sub-devices, and return the result. The error will be handled by the
	238	* caller.
	239	*/
	240	subdev_notifier->parent = notifier;
	241
	242	return v4l2_async_notifier_try_all_subdevs(subdev_notifier);
e9e31049 GL	243	}
e9e31049 GL	244
a3620cb4 SA	245	/* Test all async sub-devices in a notifier for a match. */
	246	static int v4l2_async_notifier_try_all_subdevs(
	247	struct v4l2_async_notifier *notifier)
	248	{
2cab00bb SA	249	struct v4l2_device *v4l2_dev =
	250	v4l2_async_notifier_find_v4l2_dev(notifier);
	251	struct v4l2_subdev *sd;
	252
	253	if (!v4l2_dev)
	254	return 0;
a3620cb4	255
2cab00bb SA	256	again:
2cab00bb SA	257	list_for_each_entry(sd, &subdev_list, async_list) {
a3620cb4 SA	258	struct v4l2_async_subdev *asd;
	259	int ret;
	260
	261	asd = v4l2_async_find_match(notifier, sd);
	262	if (!asd)
	263	continue;
	264
	265	ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
	266	if (ret < 0)
	267	return ret;
2cab00bb SA	268
	269	/*
	270	* v4l2_async_match_notify() may lead to registering a
	271	* new notifier and thus changing the async subdevs
	272	* list. In order to proceed safely from here, restart
	273	* parsing the list from the beginning.
	274	*/
	275	goto again;
a3620cb4 SA	276	}
	277
	278	return 0;
	279	}
	280
b426b3a6	281	static void v4l2_async_cleanup(struct v4l2_subdev *sd)
e9e31049	282	{
e9e31049	283	v4l2_device_unregister_subdev(sd);
b426b3a6 SN	284	/* Subdevice driver will reprobe and put the subdev back onto the list */
	285	list_del_init(&sd->async_list);
	286	sd->asd = NULL;
e9e31049 GL	287	}
e9e31049 GL	288
2cab00bb	289	/* Unbind all sub-devices in the notifier tree. */
fb45f436 SA	290	static void v4l2_async_notifier_unbind_all_subdevs(
	291	struct v4l2_async_notifier *notifier)
	292	{
	293	struct v4l2_subdev sd, tmp;
	294
	295	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
2cab00bb SA	296	struct v4l2_async_notifier *subdev_notifier =
	297	v4l2_async_find_subdev_notifier(sd);
	298
	299	if (subdev_notifier)
	300	v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
	301
ddddc18b	302	v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
fb45f436 SA	303	v4l2_async_cleanup(sd);
	304
	305	list_move(&sd->async_list, &subdev_list);
	306	}
2cab00bb SA	307
2cab00bb SA	308	notifier->parent = NULL;
fb45f436 SA	309	}
fb45f436 SA	310
466cae66 SA	311	/* See if an fwnode can be found in a notifier's lists. */
	312	static bool __v4l2_async_notifier_fwnode_has_async_subdev(
	313	struct v4l2_async_notifier notifier, struct fwnode_handle fwnode)
	314	{
	315	struct v4l2_async_subdev *asd;
	316	struct v4l2_subdev *sd;
	317
	318	list_for_each_entry(asd, &notifier->waiting, list) {
	319	if (asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
	320	continue;
	321
	322	if (asd->match.fwnode.fwnode == fwnode)
	323	return true;
	324	}
	325
	326	list_for_each_entry(sd, &notifier->done, async_list) {
	327	if (WARN_ON(!sd->asd))
	328	continue;
	329
	330	if (sd->asd->match_type != V4L2_ASYNC_MATCH_FWNODE)
	331	continue;
	332
	333	if (sd->asd->match.fwnode.fwnode == fwnode)
	334	return true;
	335	}
	336
	337	return false;
	338	}
	339
	340	/*
	341	* Find out whether an async sub-device was set up for an fwnode already or
	342	* whether it exists in a given notifier before @this_index.
	343	*/
	344	static bool v4l2_async_notifier_fwnode_has_async_subdev(
	345	struct v4l2_async_notifier notifier, struct fwnode_handle fwnode,
	346	unsigned int this_index)
	347	{
	348	unsigned int j;
	349
	350	lockdep_assert_held(&list_lock);
	351
	352	/* Check that an fwnode is not being added more than once. */
	353	for (j = 0; j < this_index; j++) {
	354	struct v4l2_async_subdev *asd = notifier->subdevs[this_index];
	355	struct v4l2_async_subdev *other_asd = notifier->subdevs[j];
	356
	357	if (other_asd->match_type == V4L2_ASYNC_MATCH_FWNODE &&
	358	asd->match.fwnode.fwnode ==
	359	other_asd->match.fwnode.fwnode)
	360	return true;
	361	}
	362
	363	/* Check than an fwnode did not exist in other notifiers. */
	364	list_for_each_entry(notifier, &notifier_list, list)
	365	if (__v4l2_async_notifier_fwnode_has_async_subdev(
	366	notifier, fwnode))
	367	return true;
	368
	369	return false;
	370	}
	371
a3620cb4	372	static int __v4l2_async_notifier_register(struct v4l2_async_notifier *notifier)
e9e31049	373	{
466cae66 SA	374	struct device *dev =
466cae66 SA	375	notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
e9e31049	376	struct v4l2_async_subdev *asd;
fb45f436	377	int ret;
e9e31049 GL	378	int i;
e9e31049 GL	379
a3620cb4	380	if (notifier->num_subdevs > V4L2_MAX_SUBDEVS)
e9e31049 GL	381	return -EINVAL;
e9e31049 GL	382
e9e31049 GL	383	INIT_LIST_HEAD(&notifier->waiting);
	384	INIT_LIST_HEAD(&notifier->done);
	385
466cae66 SA	386	mutex_lock(&list_lock);
466cae66 SA	387
e9e31049	388	for (i = 0; i < notifier->num_subdevs; i++) {
e8419d08	389	asd = notifier->subdevs[i];
e9e31049	390
cfca7644 SN	391	switch (asd->match_type) {
	392	case V4L2_ASYNC_MATCH_CUSTOM:
	393	case V4L2_ASYNC_MATCH_DEVNAME:
	394	case V4L2_ASYNC_MATCH_I2C:
466cae66	395	break;
ecdf0cfe	396	case V4L2_ASYNC_MATCH_FWNODE:
466cae66 SA	397	if (v4l2_async_notifier_fwnode_has_async_subdev(
	398	notifier, asd->match.fwnode.fwnode, i)) {
	399	dev_err(dev,
	400	"fwnode has already been registered or in notifier's subdev list\n");
	401	ret = -EEXIST;
	402	goto err_unlock;
	403	}
e9e31049 GL	404	break;
e9e31049 GL	405	default:
466cae66	406	dev_err(dev, "Invalid match type %u on %p\n",
cfca7644	407	asd->match_type, asd);
466cae66 SA	408	ret = -EINVAL;
466cae66 SA	409	goto err_unlock;
e9e31049 GL	410	}
	411	list_add_tail(&asd->list, &notifier->waiting);
	412	}
	413
a3620cb4	414	ret = v4l2_async_notifier_try_all_subdevs(notifier);
466cae66	415	if (ret < 0)
2cab00bb	416	goto err_unbind;
e9e31049	417
2cab00bb	418	ret = v4l2_async_notifier_try_complete(notifier);
466cae66	419	if (ret < 0)
2cab00bb	420	goto err_unbind;
fb45f436	421
47b037a0 TT	422	/* Keep also completed notifiers on the list */
	423	list_add(&notifier->list, &notifier_list);
	424
e9e31049 GL	425	mutex_unlock(&list_lock);
	426
	427	return 0;
fb45f436	428
2cab00bb SA	429	err_unbind:
	430	/*
	431	* On failure, unbind all sub-devices registered through this notifier.
	432	*/
fb45f436 SA	433	v4l2_async_notifier_unbind_all_subdevs(notifier);
fb45f436 SA	434
466cae66	435	err_unlock:
fb45f436 SA	436	mutex_unlock(&list_lock);
	437
	438	return ret;
e9e31049	439	}
a3620cb4 SA	440
	441	int v4l2_async_notifier_register(struct v4l2_device *v4l2_dev,
	442	struct v4l2_async_notifier *notifier)
	443	{
	444	int ret;
	445
2cab00bb	446	if (WARN_ON(!v4l2_dev \|\| notifier->sd))
a3620cb4 SA	447	return -EINVAL;
	448
	449	notifier->v4l2_dev = v4l2_dev;
	450
	451	ret = __v4l2_async_notifier_register(notifier);
	452	if (ret)
	453	notifier->v4l2_dev = NULL;
	454
	455	return ret;
	456	}
e9e31049 GL	457	EXPORT_SYMBOL(v4l2_async_notifier_register);
e9e31049 GL	458
2cab00bb SA	459	int v4l2_async_subdev_notifier_register(struct v4l2_subdev *sd,
	460	struct v4l2_async_notifier *notifier)
	461	{
	462	int ret;
	463
	464	if (WARN_ON(!sd \|\| notifier->v4l2_dev))
	465	return -EINVAL;
	466
	467	notifier->sd = sd;
	468
	469	ret = __v4l2_async_notifier_register(notifier);
	470	if (ret)
	471	notifier->sd = NULL;
	472
	473	return ret;
	474	}
	475	EXPORT_SYMBOL(v4l2_async_subdev_notifier_register);
	476
aef69d54 SA	477	static void __v4l2_async_notifier_unregister(
aef69d54 SA	478	struct v4l2_async_notifier *notifier)
e9e31049	479	{
aef69d54	480	if (!notifier \|\| (!notifier->v4l2_dev && !notifier->sd))
8e3fbfee LP	481	return;
8e3fbfee LP	482
fb45f436	483	v4l2_async_notifier_unbind_all_subdevs(notifier);
e9e31049	484
2cab00bb	485	notifier->sd = NULL;
8e3fbfee	486	notifier->v4l2_dev = NULL;
2cab00bb SA	487
2cab00bb SA	488	list_del(&notifier->list);
aef69d54 SA	489	}
	490
	491	void v4l2_async_notifier_unregister(struct v4l2_async_notifier *notifier)
	492	{
	493	mutex_lock(&list_lock);
	494
	495	__v4l2_async_notifier_unregister(notifier);
2cab00bb SA	496
2cab00bb SA	497	mutex_unlock(&list_lock);
e9e31049 GL	498	}
	499	EXPORT_SYMBOL(v4l2_async_notifier_unregister);
	500
9ca46531 SA	501	void v4l2_async_notifier_cleanup(struct v4l2_async_notifier *notifier)
	502	{
	503	unsigned int i;
	504
1453ad81	505	if (!notifier \|\| !notifier->max_subdevs)
9ca46531 SA	506	return;
	507
	508	for (i = 0; i < notifier->num_subdevs; i++) {
	509	struct v4l2_async_subdev *asd = notifier->subdevs[i];
	510
	511	switch (asd->match_type) {
	512	case V4L2_ASYNC_MATCH_FWNODE:
	513	fwnode_handle_put(asd->match.fwnode.fwnode);
	514	break;
	515	default:
	516	WARN_ON_ONCE(true);
	517	break;
	518	}
	519
	520	kfree(asd);
	521	}
	522
	523	notifier->max_subdevs = 0;
	524	notifier->num_subdevs = 0;
	525
	526	kvfree(notifier->subdevs);
	527	notifier->subdevs = NULL;
	528	}
	529	EXPORT_SYMBOL_GPL(v4l2_async_notifier_cleanup);
	530
e9e31049 GL	531	int v4l2_async_register_subdev(struct v4l2_subdev *sd)
e9e31049 GL	532	{
2cab00bb	533	struct v4l2_async_notifier *subdev_notifier;
e9e31049	534	struct v4l2_async_notifier *notifier;
fb45f436	535	int ret;
e9e31049	536
86217651 SA	537	/*
	538	* No reference taken. The reference is held by the device
	539	* (struct v4l2_subdev.dev), and async sub-device does not
	540	* exist independently of the device at any point of time.
	541	*/
859969b3 SA	542	if (!sd->fwnode && sd->dev)
859969b3 SA	543	sd->fwnode = dev_fwnode(sd->dev);
86217651	544
e9e31049 GL	545	mutex_lock(&list_lock);
e9e31049 GL	546
b426b3a6	547	INIT_LIST_HEAD(&sd->async_list);
e9e31049 GL	548
e9e31049 GL	549	list_for_each_entry(notifier, &notifier_list, list) {
2cab00bb SA	550	struct v4l2_device *v4l2_dev =
	551	v4l2_async_notifier_find_v4l2_dev(notifier);
	552	struct v4l2_async_subdev *asd;
fb45f436	553
2cab00bb SA	554	if (!v4l2_dev)
	555	continue;
	556
	557	asd = v4l2_async_find_match(notifier, sd);
fb45f436 SA	558	if (!asd)
	559	continue;
	560
487cc857	561	ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
fb45f436	562	if (ret)
2cab00bb	563	goto err_unbind;
fb45f436	564
2cab00bb	565	ret = v4l2_async_notifier_try_complete(notifier);
fb45f436	566	if (ret)
2cab00bb	567	goto err_unbind;
fb45f436 SA	568
fb45f436 SA	569	goto out_unlock;
e9e31049 GL	570	}
	571
	572	/* None matched, wait for hot-plugging */
b426b3a6	573	list_add(&sd->async_list, &subdev_list);
e9e31049	574
fb45f436	575	out_unlock:
e9e31049 GL	576	mutex_unlock(&list_lock);
	577
	578	return 0;
fb45f436	579
2cab00bb SA	580	err_unbind:
	581	/*
	582	* Complete failed. Unbind the sub-devices bound through registering
	583	* this async sub-device.
	584	*/
	585	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
	586	if (subdev_notifier)
	587	v4l2_async_notifier_unbind_all_subdevs(subdev_notifier);
	588
	589	if (sd->asd)
	590	v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
fb45f436 SA	591	v4l2_async_cleanup(sd);
fb45f436 SA	592
fb45f436 SA	593	mutex_unlock(&list_lock);
	594
	595	return ret;
e9e31049 GL	596	}
	597	EXPORT_SYMBOL(v4l2_async_register_subdev);
	598
	599	void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
	600	{
e9e31049 GL	601	mutex_lock(&list_lock);
e9e31049 GL	602
aef69d54 SA	603	__v4l2_async_notifier_unregister(sd->subdev_notifier);
	604	v4l2_async_notifier_cleanup(sd->subdev_notifier);
	605	kfree(sd->subdev_notifier);
	606	sd->subdev_notifier = NULL;
	607
7fc4fdb9 SA	608	if (sd->asd) {
7fc4fdb9 SA	609	struct v4l2_async_notifier *notifier = sd->notifier;
e9e31049	610
7fc4fdb9 SA	611	list_add(&sd->asd->list, &notifier->waiting);
7fc4fdb9 SA	612
ddddc18b	613	v4l2_async_notifier_call_unbind(notifier, sd, sd->asd);
7fc4fdb9	614	}
e9e31049	615
633d185b NS	616	v4l2_async_cleanup(sd);
633d185b NS	617
e9e31049 GL	618	mutex_unlock(&list_lock);
	619	}
	620	EXPORT_SYMBOL(v4l2_async_unregister_subdev);