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  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Software nodes for the firmware node framework.
  4 *
  5 * Copyright (C) 2018, Intel Corporation
  6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
  7 */
  8
  9#include <linux/device.h>
 10#include <linux/kernel.h>
 11#include <linux/property.h>
 12#include <linux/slab.h>
 13
 14struct swnode {
 15	int id;
 16	struct kobject kobj;
 17	struct fwnode_handle fwnode;
 18	const struct software_node *node;
 19
 20	/* hierarchy */
 21	struct ida child_ids;
 22	struct list_head entry;
 23	struct list_head children;
 24	struct swnode *parent;
 25
 26	unsigned int allocated:1;
 27};
 28
 29static DEFINE_IDA(swnode_root_ids);
 30static struct kset *swnode_kset;
 31
 32#define kobj_to_swnode(_kobj_) container_of(_kobj_, struct swnode, kobj)
 33
 34static const struct fwnode_operations software_node_ops;
 35
 36bool is_software_node(const struct fwnode_handle *fwnode)
 37{
 38	return !IS_ERR_OR_NULL(fwnode) && fwnode->ops == &software_node_ops;
 39}
 40EXPORT_SYMBOL_GPL(is_software_node);
 41
 42#define to_swnode(__fwnode)						\
 43	({								\
 44		typeof(__fwnode) __to_swnode_fwnode = __fwnode;		\
 45									\
 46		is_software_node(__to_swnode_fwnode) ?			\
 47			container_of(__to_swnode_fwnode,		\
 48				     struct swnode, fwnode) : NULL;	\
 49	})
 50
 51static struct swnode *
 52software_node_to_swnode(const struct software_node *node)
 53{
 54	struct swnode *swnode = NULL;
 55	struct kobject *k;
 56
 57	if (!node)
 58		return NULL;
 59
 60	spin_lock(&swnode_kset->list_lock);
 61
 62	list_for_each_entry(k, &swnode_kset->list, entry) {
 63		swnode = kobj_to_swnode(k);
 64		if (swnode->node == node)
 65			break;
 66		swnode = NULL;
 67	}
 68
 69	spin_unlock(&swnode_kset->list_lock);
 70
 71	return swnode;
 72}
 73
 74const struct software_node *to_software_node(const struct fwnode_handle *fwnode)
 75{
 76	const struct swnode *swnode = to_swnode(fwnode);
 77
 78	return swnode ? swnode->node : NULL;
 79}
 80EXPORT_SYMBOL_GPL(to_software_node);
 81
 82struct fwnode_handle *software_node_fwnode(const struct software_node *node)
 83{
 84	struct swnode *swnode = software_node_to_swnode(node);
 85
 86	return swnode ? &swnode->fwnode : NULL;
 87}
 88EXPORT_SYMBOL_GPL(software_node_fwnode);
 89
 90/* -------------------------------------------------------------------------- */
 91/* property_entry processing */
 92
 93static const struct property_entry *
 94property_entry_get(const struct property_entry *prop, const char *name)
 95{
 96	if (!prop)
 97		return NULL;
 98
 99	for (; prop->name; prop++)
100		if (!strcmp(name, prop->name))
101			return prop;
102
103	return NULL;
104}
105
106static const void *property_get_pointer(const struct property_entry *prop)
107{
108	if (!prop->length)
109		return NULL;
110
111	return prop->is_inline ? &prop->value : prop->pointer;
112}
113
114static const void *property_entry_find(const struct property_entry *props,
115				       const char *propname, size_t length)
116{
117	const struct property_entry *prop;
118	const void *pointer;
119
120	prop = property_entry_get(props, propname);
121	if (!prop)
122		return ERR_PTR(-EINVAL);
123	pointer = property_get_pointer(prop);
124	if (!pointer)
125		return ERR_PTR(-ENODATA);
126	if (length > prop->length)
127		return ERR_PTR(-EOVERFLOW);
128	return pointer;
129}
130
131static int
132property_entry_count_elems_of_size(const struct property_entry *props,
133				   const char *propname, size_t length)
134{
135	const struct property_entry *prop;
136
137	prop = property_entry_get(props, propname);
138	if (!prop)
139		return -EINVAL;
140
141	return prop->length / length;
142}
143
144static int property_entry_read_int_array(const struct property_entry *props,
145					 const char *name,
146					 unsigned int elem_size, void *val,
147					 size_t nval)
148{
149	const void *pointer;
150	size_t length;
151
152	if (!val)
153		return property_entry_count_elems_of_size(props, name,
154							  elem_size);
155
156	if (!is_power_of_2(elem_size) || elem_size > sizeof(u64))
157		return -ENXIO;
158
159	length = nval * elem_size;
160
161	pointer = property_entry_find(props, name, length);
162	if (IS_ERR(pointer))
163		return PTR_ERR(pointer);
164
165	memcpy(val, pointer, length);
166	return 0;
167}
168
169static int property_entry_read_string_array(const struct property_entry *props,
170					    const char *propname,
171					    const char **strings, size_t nval)
172{
173	const void *pointer;
174	size_t length;
175	int array_len;
176
177	/* Find out the array length. */
178	array_len = property_entry_count_elems_of_size(props, propname,
179						       sizeof(const char *));
180	if (array_len < 0)
181		return array_len;
182
183	/* Return how many there are if strings is NULL. */
184	if (!strings)
185		return array_len;
186
187	array_len = min_t(size_t, nval, array_len);
188	length = array_len * sizeof(*strings);
189
190	pointer = property_entry_find(props, propname, length);
191	if (IS_ERR(pointer))
192		return PTR_ERR(pointer);
193
194	memcpy(strings, pointer, length);
195
196	return array_len;
197}
198
199static void property_entry_free_data(const struct property_entry *p)
200{
201	const char * const *src_str;
202	size_t i, nval;
203
204	if (p->type == DEV_PROP_STRING) {
205		src_str = property_get_pointer(p);
206		nval = p->length / sizeof(*src_str);
207		for (i = 0; i < nval; i++)
208			kfree(src_str[i]);
209	}
210
211	if (!p->is_inline)
212		kfree(p->pointer);
213
214	kfree(p->name);
215}
216
217static bool property_copy_string_array(const char **dst_ptr,
218				       const char * const *src_ptr,
219				       size_t nval)
220{
221	int i;
222
223	for (i = 0; i < nval; i++) {
224		dst_ptr[i] = kstrdup(src_ptr[i], GFP_KERNEL);
225		if (!dst_ptr[i] && src_ptr[i]) {
226			while (--i >= 0)
227				kfree(dst_ptr[i]);
228			return false;
229		}
230	}
231
232	return true;
233}
234
235static int property_entry_copy_data(struct property_entry *dst,
236				    const struct property_entry *src)
237{
238	const void *pointer = property_get_pointer(src);
239	void *dst_ptr;
240	size_t nval;
241
242	/*
243	 * Properties with no data should not be marked as stored
244	 * out of line.
245	 */
246	if (!src->is_inline && !src->length)
247		return -ENODATA;
248
249	/*
250	 * Reference properties are never stored inline as
251	 * they are too big.
252	 */
253	if (src->type == DEV_PROP_REF && src->is_inline)
254		return -EINVAL;
255
256	if (src->length <= sizeof(dst->value)) {
257		dst_ptr = &dst->value;
258		dst->is_inline = true;
259	} else {
260		dst_ptr = kmalloc(src->length, GFP_KERNEL);
261		if (!dst_ptr)
262			return -ENOMEM;
263		dst->pointer = dst_ptr;
264	}
265
266	if (src->type == DEV_PROP_STRING) {
267		nval = src->length / sizeof(const char *);
268		if (!property_copy_string_array(dst_ptr, pointer, nval)) {
269			if (!dst->is_inline)
270				kfree(dst->pointer);
271			return -ENOMEM;
272		}
273	} else {
274		memcpy(dst_ptr, pointer, src->length);
275	}
276
277	dst->length = src->length;
278	dst->type = src->type;
279	dst->name = kstrdup(src->name, GFP_KERNEL);
280	if (!dst->name) {
281		property_entry_free_data(dst);
282		return -ENOMEM;
283	}
284
285	return 0;
286}
287
288/**
289 * property_entries_dup - duplicate array of properties
290 * @properties: array of properties to copy
291 *
292 * This function creates a deep copy of the given NULL-terminated array
293 * of property entries.
294 */
295struct property_entry *
296property_entries_dup(const struct property_entry *properties)
297{
298	struct property_entry *p;
299	int i, n = 0;
300	int ret;
301
302	if (!properties)
303		return NULL;
304
305	while (properties[n].name)
306		n++;
307
308	p = kcalloc(n + 1, sizeof(*p), GFP_KERNEL);
309	if (!p)
310		return ERR_PTR(-ENOMEM);
311
312	for (i = 0; i < n; i++) {
313		ret = property_entry_copy_data(&p[i], &properties[i]);
314		if (ret) {
315			while (--i >= 0)
316				property_entry_free_data(&p[i]);
317			kfree(p);
318			return ERR_PTR(ret);
319		}
320	}
321
322	return p;
323}
324EXPORT_SYMBOL_GPL(property_entries_dup);
325
326/**
327 * property_entries_free - free previously allocated array of properties
328 * @properties: array of properties to destroy
329 *
330 * This function frees given NULL-terminated array of property entries,
331 * along with their data.
332 */
333void property_entries_free(const struct property_entry *properties)
334{
335	const struct property_entry *p;
336
337	if (!properties)
338		return;
339
340	for (p = properties; p->name; p++)
341		property_entry_free_data(p);
342
343	kfree(properties);
344}
345EXPORT_SYMBOL_GPL(property_entries_free);
346
347/* -------------------------------------------------------------------------- */
348/* fwnode operations */
349
350static struct fwnode_handle *software_node_get(struct fwnode_handle *fwnode)
351{
352	struct swnode *swnode = to_swnode(fwnode);
353
354	kobject_get(&swnode->kobj);
355
356	return &swnode->fwnode;
357}
358
359static void software_node_put(struct fwnode_handle *fwnode)
360{
361	struct swnode *swnode = to_swnode(fwnode);
362
363	kobject_put(&swnode->kobj);
364}
365
366static bool software_node_property_present(const struct fwnode_handle *fwnode,
367					   const char *propname)
368{
369	struct swnode *swnode = to_swnode(fwnode);
370
371	return !!property_entry_get(swnode->node->properties, propname);
372}
373
374static int software_node_read_int_array(const struct fwnode_handle *fwnode,
375					const char *propname,
376					unsigned int elem_size, void *val,
377					size_t nval)
378{
379	struct swnode *swnode = to_swnode(fwnode);
380
381	return property_entry_read_int_array(swnode->node->properties, propname,
382					     elem_size, val, nval);
383}
384
385static int software_node_read_string_array(const struct fwnode_handle *fwnode,
386					   const char *propname,
387					   const char **val, size_t nval)
388{
389	struct swnode *swnode = to_swnode(fwnode);
390
391	return property_entry_read_string_array(swnode->node->properties,
392						propname, val, nval);
393}
394
395static const char *
396software_node_get_name(const struct fwnode_handle *fwnode)
397{
398	const struct swnode *swnode = to_swnode(fwnode);
399
400	if (!swnode)
401		return "(null)";
402
403	return kobject_name(&swnode->kobj);
404}
405
406static const char *
407software_node_get_name_prefix(const struct fwnode_handle *fwnode)
408{
409	struct fwnode_handle *parent;
410	const char *prefix;
411
412	parent = fwnode_get_parent(fwnode);
413	if (!parent)
414		return "";
415
416	/* Figure out the prefix from the parents. */
417	while (is_software_node(parent))
418		parent = fwnode_get_next_parent(parent);
419
420	prefix = fwnode_get_name_prefix(parent);
421	fwnode_handle_put(parent);
422
423	/* Guess something if prefix was NULL. */
424	return prefix ?: "/";
425}
426
427static struct fwnode_handle *
428software_node_get_parent(const struct fwnode_handle *fwnode)
429{
430	struct swnode *swnode = to_swnode(fwnode);
431
432	if (!swnode || !swnode->parent)
433		return NULL;
434
435	return fwnode_handle_get(&swnode->parent->fwnode);
436}
437
438static struct fwnode_handle *
439software_node_get_next_child(const struct fwnode_handle *fwnode,
440			     struct fwnode_handle *child)
441{
442	struct swnode *p = to_swnode(fwnode);
443	struct swnode *c = to_swnode(child);
444
445	if (!p || list_empty(&p->children) ||
446	    (c && list_is_last(&c->entry, &p->children)))
447		return NULL;
448
449	if (c)
450		c = list_next_entry(c, entry);
451	else
452		c = list_first_entry(&p->children, struct swnode, entry);
453	return &c->fwnode;
454}
455
456static struct fwnode_handle *
457software_node_get_named_child_node(const struct fwnode_handle *fwnode,
458				   const char *childname)
459{
460	struct swnode *swnode = to_swnode(fwnode);
461	struct swnode *child;
462
463	if (!swnode || list_empty(&swnode->children))
464		return NULL;
465
466	list_for_each_entry(child, &swnode->children, entry) {
467		if (!strcmp(childname, kobject_name(&child->kobj))) {
468			kobject_get(&child->kobj);
469			return &child->fwnode;
470		}
471	}
472	return NULL;
473}
474
475static int
476software_node_get_reference_args(const struct fwnode_handle *fwnode,
477				 const char *propname, const char *nargs_prop,
478				 unsigned int nargs, unsigned int index,
479				 struct fwnode_reference_args *args)
480{
481	struct swnode *swnode = to_swnode(fwnode);
482	const struct software_node_ref_args *ref_array;
483	const struct software_node_ref_args *ref;
484	const struct property_entry *prop;
485	struct fwnode_handle *refnode;
486	u32 nargs_prop_val;
487	int error;
488	int i;
489
490	if (!swnode)
491		return -ENOENT;
492
493	prop = property_entry_get(swnode->node->properties, propname);
494	if (!prop)
495		return -ENOENT;
496
497	if (prop->type != DEV_PROP_REF)
498		return -EINVAL;
499
500	/*
501	 * We expect that references are never stored inline, even
502	 * single ones, as they are too big.
503	 */
504	if (prop->is_inline)
505		return -EINVAL;
506
507	if (index * sizeof(*ref) >= prop->length)
508		return -ENOENT;
509
510	ref_array = prop->pointer;
511	ref = &ref_array[index];
512
513	refnode = software_node_fwnode(ref->node);
514	if (!refnode)
515		return -ENOENT;
516
517	if (nargs_prop) {
518		error = property_entry_read_int_array(swnode->node->properties,
519						      nargs_prop, sizeof(u32),
520						      &nargs_prop_val, 1);
521		if (error)
522			return error;
523
524		nargs = nargs_prop_val;
525	}
526
527	if (nargs > NR_FWNODE_REFERENCE_ARGS)
528		return -EINVAL;
529
530	args->fwnode = software_node_get(refnode);
531	args->nargs = nargs;
532
533	for (i = 0; i < nargs; i++)
534		args->args[i] = ref->args[i];
535
536	return 0;
537}
538
539static const struct fwnode_operations software_node_ops = {
540	.get = software_node_get,
541	.put = software_node_put,
542	.property_present = software_node_property_present,
543	.property_read_int_array = software_node_read_int_array,
544	.property_read_string_array = software_node_read_string_array,
545	.get_name = software_node_get_name,
546	.get_name_prefix = software_node_get_name_prefix,
547	.get_parent = software_node_get_parent,
548	.get_next_child_node = software_node_get_next_child,
549	.get_named_child_node = software_node_get_named_child_node,
550	.get_reference_args = software_node_get_reference_args
551};
552
553/* -------------------------------------------------------------------------- */
554
555/**
556 * software_node_find_by_name - Find software node by name
557 * @parent: Parent of the software node
558 * @name: Name of the software node
559 *
560 * The function will find a node that is child of @parent and that is named
561 * @name. If no node is found, the function returns NULL.
562 *
563 * NOTE: you will need to drop the reference with fwnode_handle_put() after use.
564 */
565const struct software_node *
566software_node_find_by_name(const struct software_node *parent, const char *name)
567{
568	struct swnode *swnode = NULL;
569	struct kobject *k;
570
571	if (!name)
572		return NULL;
573
574	spin_lock(&swnode_kset->list_lock);
575
576	list_for_each_entry(k, &swnode_kset->list, entry) {
577		swnode = kobj_to_swnode(k);
578		if (parent == swnode->node->parent && swnode->node->name &&
579		    !strcmp(name, swnode->node->name)) {
580			kobject_get(&swnode->kobj);
581			break;
582		}
583		swnode = NULL;
584	}
585
586	spin_unlock(&swnode_kset->list_lock);
587
588	return swnode ? swnode->node : NULL;
589}
590EXPORT_SYMBOL_GPL(software_node_find_by_name);
591
592static int
593software_node_register_properties(struct software_node *node,
594				  const struct property_entry *properties)
595{
596	struct property_entry *props;
597
598	props = property_entries_dup(properties);
599	if (IS_ERR(props))
600		return PTR_ERR(props);
601
602	node->properties = props;
603
604	return 0;
605}
606
607static void software_node_release(struct kobject *kobj)
608{
609	struct swnode *swnode = kobj_to_swnode(kobj);
610
611	if (swnode->parent) {
612		ida_simple_remove(&swnode->parent->child_ids, swnode->id);
613		list_del(&swnode->entry);
614	} else {
615		ida_simple_remove(&swnode_root_ids, swnode->id);
616	}
617
618	if (swnode->allocated) {
619		property_entries_free(swnode->node->properties);
620		kfree(swnode->node);
621	}
622	ida_destroy(&swnode->child_ids);
623	kfree(swnode);
624}
625
626static struct kobj_type software_node_type = {
627	.release = software_node_release,
628	.sysfs_ops = &kobj_sysfs_ops,
629};
630
631static struct fwnode_handle *
632swnode_register(const struct software_node *node, struct swnode *parent,
633		unsigned int allocated)
634{
635	struct swnode *swnode;
636	int ret;
637
638	swnode = kzalloc(sizeof(*swnode), GFP_KERNEL);
639	if (!swnode) {
640		ret = -ENOMEM;
641		goto out_err;
642	}
643
644	ret = ida_simple_get(parent ? &parent->child_ids : &swnode_root_ids,
645			     0, 0, GFP_KERNEL);
646	if (ret < 0) {
647		kfree(swnode);
648		goto out_err;
649	}
650
651	swnode->id = ret;
652	swnode->node = node;
653	swnode->parent = parent;
654	swnode->allocated = allocated;
655	swnode->kobj.kset = swnode_kset;
656	swnode->fwnode.ops = &software_node_ops;
657
658	ida_init(&swnode->child_ids);
659	INIT_LIST_HEAD(&swnode->entry);
660	INIT_LIST_HEAD(&swnode->children);
661
662	if (node->name)
663		ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
664					   parent ? &parent->kobj : NULL,
665					   "%s", node->name);
666	else
667		ret = kobject_init_and_add(&swnode->kobj, &software_node_type,
668					   parent ? &parent->kobj : NULL,
669					   "node%d", swnode->id);
670	if (ret) {
671		kobject_put(&swnode->kobj);
672		return ERR_PTR(ret);
673	}
674
675	if (parent)
676		list_add_tail(&swnode->entry, &parent->children);
677
678	kobject_uevent(&swnode->kobj, KOBJ_ADD);
679	return &swnode->fwnode;
680
681out_err:
682	if (allocated)
683		property_entries_free(node->properties);
684	return ERR_PTR(ret);
685}
686
687/**
688 * software_node_register_nodes - Register an array of software nodes
689 * @nodes: Zero terminated array of software nodes to be registered
690 *
691 * Register multiple software nodes at once.
692 */
693int software_node_register_nodes(const struct software_node *nodes)
694{
695	int ret;
696	int i;
697
698	for (i = 0; nodes[i].name; i++) {
699		ret = software_node_register(&nodes[i]);
700		if (ret) {
701			software_node_unregister_nodes(nodes);
702			return ret;
703		}
704	}
705
706	return 0;
707}
708EXPORT_SYMBOL_GPL(software_node_register_nodes);
709
710/**
711 * software_node_unregister_nodes - Unregister an array of software nodes
712 * @nodes: Zero terminated array of software nodes to be unregistered
713 *
714 * Unregister multiple software nodes at once.
715 *
716 * NOTE: Be careful using this call if the nodes had parent pointers set up in
717 * them before registering.  If so, it is wiser to remove the nodes
718 * individually, in the correct order (child before parent) instead of relying
719 * on the sequential order of the list of nodes in the array.
720 */
721void software_node_unregister_nodes(const struct software_node *nodes)
722{
723	int i;
724
725	for (i = 0; nodes[i].name; i++)
726		software_node_unregister(&nodes[i]);
727}
728EXPORT_SYMBOL_GPL(software_node_unregister_nodes);
729
730/**
731 * software_node_register_node_group - Register a group of software nodes
732 * @node_group: NULL terminated array of software node pointers to be registered
733 *
734 * Register multiple software nodes at once.
735 */
736int software_node_register_node_group(const struct software_node **node_group)
737{
738	unsigned int i;
739	int ret;
740
741	if (!node_group)
742		return 0;
743
744	for (i = 0; node_group[i]; i++) {
745		ret = software_node_register(node_group[i]);
746		if (ret) {
747			software_node_unregister_node_group(node_group);
748			return ret;
749		}
750	}
751
752	return 0;
753}
754EXPORT_SYMBOL_GPL(software_node_register_node_group);
755
756/**
757 * software_node_unregister_node_group - Unregister a group of software nodes
758 * @node_group: NULL terminated array of software node pointers to be unregistered
759 *
760 * Unregister multiple software nodes at once.
761 */
762void software_node_unregister_node_group(const struct software_node **node_group)
763{
764	unsigned int i;
765
766	if (!node_group)
767		return;
768
769	for (i = 0; node_group[i]; i++)
770		software_node_unregister(node_group[i]);
771}
772EXPORT_SYMBOL_GPL(software_node_unregister_node_group);
773
774/**
775 * software_node_register - Register static software node
776 * @node: The software node to be registered
777 */
778int software_node_register(const struct software_node *node)
779{
780	struct swnode *parent = software_node_to_swnode(node->parent);
781
782	if (software_node_to_swnode(node))
783		return -EEXIST;
784
785	return PTR_ERR_OR_ZERO(swnode_register(node, parent, 0));
786}
787EXPORT_SYMBOL_GPL(software_node_register);
788
789/**
790 * software_node_unregister - Unregister static software node
791 * @node: The software node to be unregistered
792 */
793void software_node_unregister(const struct software_node *node)
794{
795	struct swnode *swnode;
796
797	swnode = software_node_to_swnode(node);
798	if (swnode)
799		fwnode_remove_software_node(&swnode->fwnode);
800}
801EXPORT_SYMBOL_GPL(software_node_unregister);
802
803struct fwnode_handle *
804fwnode_create_software_node(const struct property_entry *properties,
805			    const struct fwnode_handle *parent)
806{
807	struct software_node *node;
808	struct swnode *p = NULL;
809	int ret;
810
811	if (parent) {
812		if (IS_ERR(parent))
813			return ERR_CAST(parent);
814		if (!is_software_node(parent))
815			return ERR_PTR(-EINVAL);
816		p = to_swnode(parent);
817	}
818
819	node = kzalloc(sizeof(*node), GFP_KERNEL);
820	if (!node)
821		return ERR_PTR(-ENOMEM);
822
823	ret = software_node_register_properties(node, properties);
824	if (ret) {
825		kfree(node);
826		return ERR_PTR(ret);
827	}
828
829	node->parent = p ? p->node : NULL;
830
831	return swnode_register(node, p, 1);
832}
833EXPORT_SYMBOL_GPL(fwnode_create_software_node);
834
835void fwnode_remove_software_node(struct fwnode_handle *fwnode)
836{
837	struct swnode *swnode = to_swnode(fwnode);
838
839	if (!swnode)
840		return;
841
842	kobject_put(&swnode->kobj);
843}
844EXPORT_SYMBOL_GPL(fwnode_remove_software_node);
845
846int software_node_notify(struct device *dev, unsigned long action)
847{
848	struct fwnode_handle *fwnode = dev_fwnode(dev);
849	struct swnode *swnode;
850	int ret;
851
852	if (!fwnode)
853		return 0;
854
855	if (!is_software_node(fwnode))
856		fwnode = fwnode->secondary;
857	if (!is_software_node(fwnode))
858		return 0;
859
860	swnode = to_swnode(fwnode);
861
862	switch (action) {
863	case KOBJ_ADD:
864		ret = sysfs_create_link(&dev->kobj, &swnode->kobj,
865					"software_node");
866		if (ret)
867			break;
868
869		ret = sysfs_create_link(&swnode->kobj, &dev->kobj,
870					dev_name(dev));
871		if (ret) {
872			sysfs_remove_link(&dev->kobj, "software_node");
873			break;
874		}
875		kobject_get(&swnode->kobj);
876		break;
877	case KOBJ_REMOVE:
878		sysfs_remove_link(&swnode->kobj, dev_name(dev));
879		sysfs_remove_link(&dev->kobj, "software_node");
880		kobject_put(&swnode->kobj);
881		break;
882	default:
883		break;
884	}
885
886	return 0;
887}
888
889static int __init software_node_init(void)
890{
891	swnode_kset = kset_create_and_add("software_nodes", NULL, kernel_kobj);
892	if (!swnode_kset)
893		return -ENOMEM;
894	return 0;
895}
896postcore_initcall(software_node_init);
897
898static void __exit software_node_exit(void)
899{
900	ida_destroy(&swnode_root_ids);
901	kset_unregister(swnode_kset);
902}
903__exitcall(software_node_exit);