cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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v4l2-async.c (21567B)


      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * V4L2 asynchronous subdevice registration API
      4 *
      5 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
      6 */
      7
      8#include <linux/debugfs.h>
      9#include <linux/device.h>
     10#include <linux/err.h>
     11#include <linux/i2c.h>
     12#include <linux/list.h>
     13#include <linux/mm.h>
     14#include <linux/module.h>
     15#include <linux/mutex.h>
     16#include <linux/of.h>
     17#include <linux/platform_device.h>
     18#include <linux/seq_file.h>
     19#include <linux/slab.h>
     20#include <linux/types.h>
     21
     22#include <media/v4l2-async.h>
     23#include <media/v4l2-device.h>
     24#include <media/v4l2-fwnode.h>
     25#include <media/v4l2-subdev.h>
     26
     27static int v4l2_async_nf_call_bound(struct v4l2_async_notifier *n,
     28				    struct v4l2_subdev *subdev,
     29				    struct v4l2_async_subdev *asd)
     30{
     31	if (!n->ops || !n->ops->bound)
     32		return 0;
     33
     34	return n->ops->bound(n, subdev, asd);
     35}
     36
     37static void v4l2_async_nf_call_unbind(struct v4l2_async_notifier *n,
     38				      struct v4l2_subdev *subdev,
     39				      struct v4l2_async_subdev *asd)
     40{
     41	if (!n->ops || !n->ops->unbind)
     42		return;
     43
     44	n->ops->unbind(n, subdev, asd);
     45}
     46
     47static int v4l2_async_nf_call_complete(struct v4l2_async_notifier *n)
     48{
     49	if (!n->ops || !n->ops->complete)
     50		return 0;
     51
     52	return n->ops->complete(n);
     53}
     54
     55static bool match_i2c(struct v4l2_async_notifier *notifier,
     56		      struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
     57{
     58#if IS_ENABLED(CONFIG_I2C)
     59	struct i2c_client *client = i2c_verify_client(sd->dev);
     60
     61	return client &&
     62		asd->match.i2c.adapter_id == client->adapter->nr &&
     63		asd->match.i2c.address == client->addr;
     64#else
     65	return false;
     66#endif
     67}
     68
     69static bool match_fwnode(struct v4l2_async_notifier *notifier,
     70			 struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
     71{
     72	struct fwnode_handle *other_fwnode;
     73	struct fwnode_handle *dev_fwnode;
     74	bool asd_fwnode_is_ep;
     75	bool sd_fwnode_is_ep;
     76	struct device *dev;
     77
     78	/*
     79	 * Both the subdev and the async subdev can provide either an endpoint
     80	 * fwnode or a device fwnode. Start with the simple case of direct
     81	 * fwnode matching.
     82	 */
     83	if (sd->fwnode == asd->match.fwnode)
     84		return true;
     85
     86	/*
     87	 * Check the same situation for any possible secondary assigned to the
     88	 * subdev's fwnode
     89	 */
     90	if (!IS_ERR_OR_NULL(sd->fwnode->secondary) &&
     91	    sd->fwnode->secondary == asd->match.fwnode)
     92		return true;
     93
     94	/*
     95	 * Otherwise, check if the sd fwnode and the asd fwnode refer to an
     96	 * endpoint or a device. If they're of the same type, there's no match.
     97	 * Technically speaking this checks if the nodes refer to a connected
     98	 * endpoint, which is the simplest check that works for both OF and
     99	 * ACPI. This won't make a difference, as drivers should not try to
    100	 * match unconnected endpoints.
    101	 */
    102	sd_fwnode_is_ep = fwnode_graph_is_endpoint(sd->fwnode);
    103	asd_fwnode_is_ep = fwnode_graph_is_endpoint(asd->match.fwnode);
    104
    105	if (sd_fwnode_is_ep == asd_fwnode_is_ep)
    106		return false;
    107
    108	/*
    109	 * The sd and asd fwnodes are of different types. Get the device fwnode
    110	 * parent of the endpoint fwnode, and compare it with the other fwnode.
    111	 */
    112	if (sd_fwnode_is_ep) {
    113		dev_fwnode = fwnode_graph_get_port_parent(sd->fwnode);
    114		other_fwnode = asd->match.fwnode;
    115	} else {
    116		dev_fwnode = fwnode_graph_get_port_parent(asd->match.fwnode);
    117		other_fwnode = sd->fwnode;
    118	}
    119
    120	fwnode_handle_put(dev_fwnode);
    121
    122	if (dev_fwnode != other_fwnode)
    123		return false;
    124
    125	/*
    126	 * We have a heterogeneous match. Retrieve the struct device of the side
    127	 * that matched on a device fwnode to print its driver name.
    128	 */
    129	if (sd_fwnode_is_ep)
    130		dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
    131		    : notifier->sd->dev;
    132	else
    133		dev = sd->dev;
    134
    135	if (dev && dev->driver) {
    136		if (sd_fwnode_is_ep)
    137			dev_warn(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
    138				 dev->driver->name);
    139		dev_notice(dev, "Consider updating driver %s to match on endpoints\n",
    140			   dev->driver->name);
    141	}
    142
    143	return true;
    144}
    145
    146static LIST_HEAD(subdev_list);
    147static LIST_HEAD(notifier_list);
    148static DEFINE_MUTEX(list_lock);
    149
    150static struct v4l2_async_subdev *
    151v4l2_async_find_match(struct v4l2_async_notifier *notifier,
    152		      struct v4l2_subdev *sd)
    153{
    154	bool (*match)(struct v4l2_async_notifier *notifier,
    155		      struct v4l2_subdev *sd, struct v4l2_async_subdev *asd);
    156	struct v4l2_async_subdev *asd;
    157
    158	list_for_each_entry(asd, &notifier->waiting, list) {
    159		/* bus_type has been verified valid before */
    160		switch (asd->match_type) {
    161		case V4L2_ASYNC_MATCH_I2C:
    162			match = match_i2c;
    163			break;
    164		case V4L2_ASYNC_MATCH_FWNODE:
    165			match = match_fwnode;
    166			break;
    167		default:
    168			/* Cannot happen, unless someone breaks us */
    169			WARN_ON(true);
    170			return NULL;
    171		}
    172
    173		/* match cannot be NULL here */
    174		if (match(notifier, sd, asd))
    175			return asd;
    176	}
    177
    178	return NULL;
    179}
    180
    181/* Compare two async sub-device descriptors for equivalence */
    182static bool asd_equal(struct v4l2_async_subdev *asd_x,
    183		      struct v4l2_async_subdev *asd_y)
    184{
    185	if (asd_x->match_type != asd_y->match_type)
    186		return false;
    187
    188	switch (asd_x->match_type) {
    189	case V4L2_ASYNC_MATCH_I2C:
    190		return asd_x->match.i2c.adapter_id ==
    191			asd_y->match.i2c.adapter_id &&
    192			asd_x->match.i2c.address ==
    193			asd_y->match.i2c.address;
    194	case V4L2_ASYNC_MATCH_FWNODE:
    195		return asd_x->match.fwnode == asd_y->match.fwnode;
    196	default:
    197		break;
    198	}
    199
    200	return false;
    201}
    202
    203/* Find the sub-device notifier registered by a sub-device driver. */
    204static struct v4l2_async_notifier *
    205v4l2_async_find_subdev_notifier(struct v4l2_subdev *sd)
    206{
    207	struct v4l2_async_notifier *n;
    208
    209	list_for_each_entry(n, &notifier_list, list)
    210		if (n->sd == sd)
    211			return n;
    212
    213	return NULL;
    214}
    215
    216/* Get v4l2_device related to the notifier if one can be found. */
    217static struct v4l2_device *
    218v4l2_async_nf_find_v4l2_dev(struct v4l2_async_notifier *notifier)
    219{
    220	while (notifier->parent)
    221		notifier = notifier->parent;
    222
    223	return notifier->v4l2_dev;
    224}
    225
    226/*
    227 * Return true if all child sub-device notifiers are complete, false otherwise.
    228 */
    229static bool
    230v4l2_async_nf_can_complete(struct v4l2_async_notifier *notifier)
    231{
    232	struct v4l2_subdev *sd;
    233
    234	if (!list_empty(&notifier->waiting))
    235		return false;
    236
    237	list_for_each_entry(sd, &notifier->done, async_list) {
    238		struct v4l2_async_notifier *subdev_notifier =
    239			v4l2_async_find_subdev_notifier(sd);
    240
    241		if (subdev_notifier &&
    242		    !v4l2_async_nf_can_complete(subdev_notifier))
    243			return false;
    244	}
    245
    246	return true;
    247}
    248
    249/*
    250 * Complete the master notifier if possible. This is done when all async
    251 * sub-devices have been bound; v4l2_device is also available then.
    252 */
    253static int
    254v4l2_async_nf_try_complete(struct v4l2_async_notifier *notifier)
    255{
    256	/* Quick check whether there are still more sub-devices here. */
    257	if (!list_empty(&notifier->waiting))
    258		return 0;
    259
    260	/* Check the entire notifier tree; find the root notifier first. */
    261	while (notifier->parent)
    262		notifier = notifier->parent;
    263
    264	/* This is root if it has v4l2_dev. */
    265	if (!notifier->v4l2_dev)
    266		return 0;
    267
    268	/* Is everything ready? */
    269	if (!v4l2_async_nf_can_complete(notifier))
    270		return 0;
    271
    272	return v4l2_async_nf_call_complete(notifier);
    273}
    274
    275static int
    276v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier);
    277
    278static int v4l2_async_create_ancillary_links(struct v4l2_async_notifier *n,
    279					     struct v4l2_subdev *sd)
    280{
    281	struct media_link *link = NULL;
    282
    283#if IS_ENABLED(CONFIG_MEDIA_CONTROLLER)
    284
    285	if (sd->entity.function != MEDIA_ENT_F_LENS &&
    286	    sd->entity.function != MEDIA_ENT_F_FLASH)
    287		return 0;
    288
    289	link = media_create_ancillary_link(&n->sd->entity, &sd->entity);
    290
    291#endif
    292
    293	return IS_ERR(link) ? PTR_ERR(link) : 0;
    294}
    295
    296static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
    297				   struct v4l2_device *v4l2_dev,
    298				   struct v4l2_subdev *sd,
    299				   struct v4l2_async_subdev *asd)
    300{
    301	struct v4l2_async_notifier *subdev_notifier;
    302	int ret;
    303
    304	ret = v4l2_device_register_subdev(v4l2_dev, sd);
    305	if (ret < 0)
    306		return ret;
    307
    308	ret = v4l2_async_nf_call_bound(notifier, sd, asd);
    309	if (ret < 0) {
    310		v4l2_device_unregister_subdev(sd);
    311		return ret;
    312	}
    313
    314	/*
    315	 * Depending of the function of the entities involved, we may want to
    316	 * create links between them (for example between a sensor and its lens
    317	 * or between a sensor's source pad and the connected device's sink
    318	 * pad).
    319	 */
    320	ret = v4l2_async_create_ancillary_links(notifier, sd);
    321	if (ret) {
    322		v4l2_async_nf_call_unbind(notifier, sd, asd);
    323		v4l2_device_unregister_subdev(sd);
    324		return ret;
    325	}
    326
    327	/* Remove from the waiting list */
    328	list_del(&asd->list);
    329	sd->asd = asd;
    330	sd->notifier = notifier;
    331
    332	/* Move from the global subdevice list to notifier's done */
    333	list_move(&sd->async_list, &notifier->done);
    334
    335	/*
    336	 * See if the sub-device has a notifier. If not, return here.
    337	 */
    338	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
    339	if (!subdev_notifier || subdev_notifier->parent)
    340		return 0;
    341
    342	/*
    343	 * Proceed with checking for the sub-device notifier's async
    344	 * sub-devices, and return the result. The error will be handled by the
    345	 * caller.
    346	 */
    347	subdev_notifier->parent = notifier;
    348
    349	return v4l2_async_nf_try_all_subdevs(subdev_notifier);
    350}
    351
    352/* Test all async sub-devices in a notifier for a match. */
    353static int
    354v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier)
    355{
    356	struct v4l2_device *v4l2_dev =
    357		v4l2_async_nf_find_v4l2_dev(notifier);
    358	struct v4l2_subdev *sd;
    359
    360	if (!v4l2_dev)
    361		return 0;
    362
    363again:
    364	list_for_each_entry(sd, &subdev_list, async_list) {
    365		struct v4l2_async_subdev *asd;
    366		int ret;
    367
    368		asd = v4l2_async_find_match(notifier, sd);
    369		if (!asd)
    370			continue;
    371
    372		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
    373		if (ret < 0)
    374			return ret;
    375
    376		/*
    377		 * v4l2_async_match_notify() may lead to registering a
    378		 * new notifier and thus changing the async subdevs
    379		 * list. In order to proceed safely from here, restart
    380		 * parsing the list from the beginning.
    381		 */
    382		goto again;
    383	}
    384
    385	return 0;
    386}
    387
    388static void v4l2_async_cleanup(struct v4l2_subdev *sd)
    389{
    390	v4l2_device_unregister_subdev(sd);
    391	/*
    392	 * Subdevice driver will reprobe and put the subdev back
    393	 * onto the list
    394	 */
    395	list_del_init(&sd->async_list);
    396	sd->asd = NULL;
    397}
    398
    399/* Unbind all sub-devices in the notifier tree. */
    400static void
    401v4l2_async_nf_unbind_all_subdevs(struct v4l2_async_notifier *notifier)
    402{
    403	struct v4l2_subdev *sd, *tmp;
    404
    405	list_for_each_entry_safe(sd, tmp, &notifier->done, async_list) {
    406		struct v4l2_async_notifier *subdev_notifier =
    407			v4l2_async_find_subdev_notifier(sd);
    408
    409		if (subdev_notifier)
    410			v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
    411
    412		v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
    413		v4l2_async_cleanup(sd);
    414
    415		list_move(&sd->async_list, &subdev_list);
    416	}
    417
    418	notifier->parent = NULL;
    419}
    420
    421/* See if an async sub-device can be found in a notifier's lists. */
    422static bool
    423__v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
    424				 struct v4l2_async_subdev *asd)
    425{
    426	struct v4l2_async_subdev *asd_y;
    427	struct v4l2_subdev *sd;
    428
    429	list_for_each_entry(asd_y, &notifier->waiting, list)
    430		if (asd_equal(asd, asd_y))
    431			return true;
    432
    433	list_for_each_entry(sd, &notifier->done, async_list) {
    434		if (WARN_ON(!sd->asd))
    435			continue;
    436
    437		if (asd_equal(asd, sd->asd))
    438			return true;
    439	}
    440
    441	return false;
    442}
    443
    444/*
    445 * Find out whether an async sub-device was set up already or
    446 * whether it exists in a given notifier before @this_index.
    447 * If @this_index < 0, search the notifier's entire @asd_list.
    448 */
    449static bool
    450v4l2_async_nf_has_async_subdev(struct v4l2_async_notifier *notifier,
    451			       struct v4l2_async_subdev *asd, int this_index)
    452{
    453	struct v4l2_async_subdev *asd_y;
    454	int j = 0;
    455
    456	lockdep_assert_held(&list_lock);
    457
    458	/* Check that an asd is not being added more than once. */
    459	list_for_each_entry(asd_y, &notifier->asd_list, asd_list) {
    460		if (this_index >= 0 && j++ >= this_index)
    461			break;
    462		if (asd_equal(asd, asd_y))
    463			return true;
    464	}
    465
    466	/* Check that an asd does not exist in other notifiers. */
    467	list_for_each_entry(notifier, &notifier_list, list)
    468		if (__v4l2_async_nf_has_async_subdev(notifier, asd))
    469			return true;
    470
    471	return false;
    472}
    473
    474static int v4l2_async_nf_asd_valid(struct v4l2_async_notifier *notifier,
    475				   struct v4l2_async_subdev *asd,
    476				   int this_index)
    477{
    478	struct device *dev =
    479		notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
    480
    481	if (!asd)
    482		return -EINVAL;
    483
    484	switch (asd->match_type) {
    485	case V4L2_ASYNC_MATCH_I2C:
    486	case V4L2_ASYNC_MATCH_FWNODE:
    487		if (v4l2_async_nf_has_async_subdev(notifier, asd, this_index)) {
    488			dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");
    489			return -EEXIST;
    490		}
    491		break;
    492	default:
    493		dev_err(dev, "Invalid match type %u on %p\n",
    494			asd->match_type, asd);
    495		return -EINVAL;
    496	}
    497
    498	return 0;
    499}
    500
    501void v4l2_async_nf_init(struct v4l2_async_notifier *notifier)
    502{
    503	INIT_LIST_HEAD(&notifier->asd_list);
    504}
    505EXPORT_SYMBOL(v4l2_async_nf_init);
    506
    507static int __v4l2_async_nf_register(struct v4l2_async_notifier *notifier)
    508{
    509	struct v4l2_async_subdev *asd;
    510	int ret, i = 0;
    511
    512	INIT_LIST_HEAD(&notifier->waiting);
    513	INIT_LIST_HEAD(&notifier->done);
    514
    515	mutex_lock(&list_lock);
    516
    517	list_for_each_entry(asd, &notifier->asd_list, asd_list) {
    518		ret = v4l2_async_nf_asd_valid(notifier, asd, i++);
    519		if (ret)
    520			goto err_unlock;
    521
    522		list_add_tail(&asd->list, &notifier->waiting);
    523	}
    524
    525	ret = v4l2_async_nf_try_all_subdevs(notifier);
    526	if (ret < 0)
    527		goto err_unbind;
    528
    529	ret = v4l2_async_nf_try_complete(notifier);
    530	if (ret < 0)
    531		goto err_unbind;
    532
    533	/* Keep also completed notifiers on the list */
    534	list_add(&notifier->list, &notifier_list);
    535
    536	mutex_unlock(&list_lock);
    537
    538	return 0;
    539
    540err_unbind:
    541	/*
    542	 * On failure, unbind all sub-devices registered through this notifier.
    543	 */
    544	v4l2_async_nf_unbind_all_subdevs(notifier);
    545
    546err_unlock:
    547	mutex_unlock(&list_lock);
    548
    549	return ret;
    550}
    551
    552int v4l2_async_nf_register(struct v4l2_device *v4l2_dev,
    553			   struct v4l2_async_notifier *notifier)
    554{
    555	int ret;
    556
    557	if (WARN_ON(!v4l2_dev || notifier->sd))
    558		return -EINVAL;
    559
    560	notifier->v4l2_dev = v4l2_dev;
    561
    562	ret = __v4l2_async_nf_register(notifier);
    563	if (ret)
    564		notifier->v4l2_dev = NULL;
    565
    566	return ret;
    567}
    568EXPORT_SYMBOL(v4l2_async_nf_register);
    569
    570int v4l2_async_subdev_nf_register(struct v4l2_subdev *sd,
    571				  struct v4l2_async_notifier *notifier)
    572{
    573	int ret;
    574
    575	if (WARN_ON(!sd || notifier->v4l2_dev))
    576		return -EINVAL;
    577
    578	notifier->sd = sd;
    579
    580	ret = __v4l2_async_nf_register(notifier);
    581	if (ret)
    582		notifier->sd = NULL;
    583
    584	return ret;
    585}
    586EXPORT_SYMBOL(v4l2_async_subdev_nf_register);
    587
    588static void
    589__v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
    590{
    591	if (!notifier || (!notifier->v4l2_dev && !notifier->sd))
    592		return;
    593
    594	v4l2_async_nf_unbind_all_subdevs(notifier);
    595
    596	notifier->sd = NULL;
    597	notifier->v4l2_dev = NULL;
    598
    599	list_del(&notifier->list);
    600}
    601
    602void v4l2_async_nf_unregister(struct v4l2_async_notifier *notifier)
    603{
    604	mutex_lock(&list_lock);
    605
    606	__v4l2_async_nf_unregister(notifier);
    607
    608	mutex_unlock(&list_lock);
    609}
    610EXPORT_SYMBOL(v4l2_async_nf_unregister);
    611
    612static void __v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
    613{
    614	struct v4l2_async_subdev *asd, *tmp;
    615
    616	if (!notifier || !notifier->asd_list.next)
    617		return;
    618
    619	list_for_each_entry_safe(asd, tmp, &notifier->asd_list, asd_list) {
    620		switch (asd->match_type) {
    621		case V4L2_ASYNC_MATCH_FWNODE:
    622			fwnode_handle_put(asd->match.fwnode);
    623			break;
    624		default:
    625			break;
    626		}
    627
    628		list_del(&asd->asd_list);
    629		kfree(asd);
    630	}
    631}
    632
    633void v4l2_async_nf_cleanup(struct v4l2_async_notifier *notifier)
    634{
    635	mutex_lock(&list_lock);
    636
    637	__v4l2_async_nf_cleanup(notifier);
    638
    639	mutex_unlock(&list_lock);
    640}
    641EXPORT_SYMBOL_GPL(v4l2_async_nf_cleanup);
    642
    643int __v4l2_async_nf_add_subdev(struct v4l2_async_notifier *notifier,
    644			       struct v4l2_async_subdev *asd)
    645{
    646	int ret;
    647
    648	mutex_lock(&list_lock);
    649
    650	ret = v4l2_async_nf_asd_valid(notifier, asd, -1);
    651	if (ret)
    652		goto unlock;
    653
    654	list_add_tail(&asd->asd_list, &notifier->asd_list);
    655
    656unlock:
    657	mutex_unlock(&list_lock);
    658	return ret;
    659}
    660EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_subdev);
    661
    662struct v4l2_async_subdev *
    663__v4l2_async_nf_add_fwnode(struct v4l2_async_notifier *notifier,
    664			   struct fwnode_handle *fwnode,
    665			   unsigned int asd_struct_size)
    666{
    667	struct v4l2_async_subdev *asd;
    668	int ret;
    669
    670	asd = kzalloc(asd_struct_size, GFP_KERNEL);
    671	if (!asd)
    672		return ERR_PTR(-ENOMEM);
    673
    674	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
    675	asd->match.fwnode = fwnode_handle_get(fwnode);
    676
    677	ret = __v4l2_async_nf_add_subdev(notifier, asd);
    678	if (ret) {
    679		fwnode_handle_put(fwnode);
    680		kfree(asd);
    681		return ERR_PTR(ret);
    682	}
    683
    684	return asd;
    685}
    686EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode);
    687
    688struct v4l2_async_subdev *
    689__v4l2_async_nf_add_fwnode_remote(struct v4l2_async_notifier *notif,
    690				  struct fwnode_handle *endpoint,
    691				  unsigned int asd_struct_size)
    692{
    693	struct v4l2_async_subdev *asd;
    694	struct fwnode_handle *remote;
    695
    696	remote = fwnode_graph_get_remote_endpoint(endpoint);
    697	if (!remote)
    698		return ERR_PTR(-ENOTCONN);
    699
    700	asd = __v4l2_async_nf_add_fwnode(notif, remote, asd_struct_size);
    701	/*
    702	 * Calling __v4l2_async_nf_add_fwnode grabs a refcount,
    703	 * so drop the one we got in fwnode_graph_get_remote_port_parent.
    704	 */
    705	fwnode_handle_put(remote);
    706	return asd;
    707}
    708EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_fwnode_remote);
    709
    710struct v4l2_async_subdev *
    711__v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier, int adapter_id,
    712			unsigned short address, unsigned int asd_struct_size)
    713{
    714	struct v4l2_async_subdev *asd;
    715	int ret;
    716
    717	asd = kzalloc(asd_struct_size, GFP_KERNEL);
    718	if (!asd)
    719		return ERR_PTR(-ENOMEM);
    720
    721	asd->match_type = V4L2_ASYNC_MATCH_I2C;
    722	asd->match.i2c.adapter_id = adapter_id;
    723	asd->match.i2c.address = address;
    724
    725	ret = __v4l2_async_nf_add_subdev(notifier, asd);
    726	if (ret) {
    727		kfree(asd);
    728		return ERR_PTR(ret);
    729	}
    730
    731	return asd;
    732}
    733EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_i2c);
    734
    735int v4l2_async_register_subdev(struct v4l2_subdev *sd)
    736{
    737	struct v4l2_async_notifier *subdev_notifier;
    738	struct v4l2_async_notifier *notifier;
    739	int ret;
    740
    741	/*
    742	 * No reference taken. The reference is held by the device
    743	 * (struct v4l2_subdev.dev), and async sub-device does not
    744	 * exist independently of the device at any point of time.
    745	 */
    746	if (!sd->fwnode && sd->dev)
    747		sd->fwnode = dev_fwnode(sd->dev);
    748
    749	mutex_lock(&list_lock);
    750
    751	INIT_LIST_HEAD(&sd->async_list);
    752
    753	list_for_each_entry(notifier, &notifier_list, list) {
    754		struct v4l2_device *v4l2_dev =
    755			v4l2_async_nf_find_v4l2_dev(notifier);
    756		struct v4l2_async_subdev *asd;
    757
    758		if (!v4l2_dev)
    759			continue;
    760
    761		asd = v4l2_async_find_match(notifier, sd);
    762		if (!asd)
    763			continue;
    764
    765		ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
    766		if (ret)
    767			goto err_unbind;
    768
    769		ret = v4l2_async_nf_try_complete(notifier);
    770		if (ret)
    771			goto err_unbind;
    772
    773		goto out_unlock;
    774	}
    775
    776	/* None matched, wait for hot-plugging */
    777	list_add(&sd->async_list, &subdev_list);
    778
    779out_unlock:
    780	mutex_unlock(&list_lock);
    781
    782	return 0;
    783
    784err_unbind:
    785	/*
    786	 * Complete failed. Unbind the sub-devices bound through registering
    787	 * this async sub-device.
    788	 */
    789	subdev_notifier = v4l2_async_find_subdev_notifier(sd);
    790	if (subdev_notifier)
    791		v4l2_async_nf_unbind_all_subdevs(subdev_notifier);
    792
    793	if (sd->asd)
    794		v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
    795	v4l2_async_cleanup(sd);
    796
    797	mutex_unlock(&list_lock);
    798
    799	return ret;
    800}
    801EXPORT_SYMBOL(v4l2_async_register_subdev);
    802
    803void v4l2_async_unregister_subdev(struct v4l2_subdev *sd)
    804{
    805	if (!sd->async_list.next)
    806		return;
    807
    808	mutex_lock(&list_lock);
    809
    810	__v4l2_async_nf_unregister(sd->subdev_notifier);
    811	__v4l2_async_nf_cleanup(sd->subdev_notifier);
    812	kfree(sd->subdev_notifier);
    813	sd->subdev_notifier = NULL;
    814
    815	if (sd->asd) {
    816		struct v4l2_async_notifier *notifier = sd->notifier;
    817
    818		list_add(&sd->asd->list, &notifier->waiting);
    819
    820		v4l2_async_nf_call_unbind(notifier, sd, sd->asd);
    821	}
    822
    823	v4l2_async_cleanup(sd);
    824
    825	mutex_unlock(&list_lock);
    826}
    827EXPORT_SYMBOL(v4l2_async_unregister_subdev);
    828
    829static void print_waiting_subdev(struct seq_file *s,
    830				 struct v4l2_async_subdev *asd)
    831{
    832	switch (asd->match_type) {
    833	case V4L2_ASYNC_MATCH_I2C:
    834		seq_printf(s, " [i2c] dev=%d-%04x\n", asd->match.i2c.adapter_id,
    835			   asd->match.i2c.address);
    836		break;
    837	case V4L2_ASYNC_MATCH_FWNODE: {
    838		struct fwnode_handle *devnode, *fwnode = asd->match.fwnode;
    839
    840		devnode = fwnode_graph_is_endpoint(fwnode) ?
    841			  fwnode_graph_get_port_parent(fwnode) :
    842			  fwnode_handle_get(fwnode);
    843
    844		seq_printf(s, " [fwnode] dev=%s, node=%pfw\n",
    845			   devnode->dev ? dev_name(devnode->dev) : "nil",
    846			   fwnode);
    847
    848		fwnode_handle_put(devnode);
    849		break;
    850	}
    851	}
    852}
    853
    854static const char *
    855v4l2_async_nf_name(struct v4l2_async_notifier *notifier)
    856{
    857	if (notifier->v4l2_dev)
    858		return notifier->v4l2_dev->name;
    859	else if (notifier->sd)
    860		return notifier->sd->name;
    861	else
    862		return "nil";
    863}
    864
    865static int pending_subdevs_show(struct seq_file *s, void *data)
    866{
    867	struct v4l2_async_notifier *notif;
    868	struct v4l2_async_subdev *asd;
    869
    870	mutex_lock(&list_lock);
    871
    872	list_for_each_entry(notif, &notifier_list, list) {
    873		seq_printf(s, "%s:\n", v4l2_async_nf_name(notif));
    874		list_for_each_entry(asd, &notif->waiting, list)
    875			print_waiting_subdev(s, asd);
    876	}
    877
    878	mutex_unlock(&list_lock);
    879
    880	return 0;
    881}
    882DEFINE_SHOW_ATTRIBUTE(pending_subdevs);
    883
    884static struct dentry *v4l2_async_debugfs_dir;
    885
    886static int __init v4l2_async_init(void)
    887{
    888	v4l2_async_debugfs_dir = debugfs_create_dir("v4l2-async", NULL);
    889	debugfs_create_file("pending_async_subdevices", 0444,
    890			    v4l2_async_debugfs_dir, NULL,
    891			    &pending_subdevs_fops);
    892
    893	return 0;
    894}
    895
    896static void __exit v4l2_async_exit(void)
    897{
    898	debugfs_remove_recursive(v4l2_async_debugfs_dir);
    899}
    900
    901subsys_initcall(v4l2_async_init);
    902module_exit(v4l2_async_exit);
    903
    904MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
    905MODULE_AUTHOR("Sakari Ailus <sakari.ailus@linux.intel.com>");
    906MODULE_AUTHOR("Ezequiel Garcia <ezequiel@collabora.com>");
    907MODULE_LICENSE("GPL");