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Commit b56b5528 authored by Rob Herring's avatar Rob Herring
Browse files

of: make kobject and bin_attribute support configurable 



Having device_nodes be kobjects is only needed if sysfs or OF_DYNAMIC is
enabled. Otherwise, having a kobject in struct device_node is
unnecessary bloat in minimal kernel configurations.

Likewise, bin_attribute is only needed in struct property when sysfs is
enabled, so we can make it configurable too.

Tested-by: default avatarNicolas Pitre <nico@linaro.org>
Reviewed-by: default avatarFrank Rowand <frowand.list@gmail.com>
Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent 0c3c234b

drivers/of/Kconfig

+4 −0
Original line number Diff line number Diff line
@@ -46,10 +46,14 @@ config OF_EARLY_FLATTREE 
config OF_PROMTREE

	bool



config OF_KOBJ

	def_bool SYSFS



# Hardly any platforms need this.  It is safe to select, but only do so if you

# need it.

config OF_DYNAMIC

	bool "Support for dynamic device trees" if OF_UNITTEST

	select OF_KOBJ

	help

	  On some platforms, the device tree can be manipulated at runtime.

	  While this option is selected automatically on such platforms, you

drivers/of/Makefile

+1 −0
Original line number Diff line number Diff line 
obj-y = base.o device.o platform.o property.o

obj-$(CONFIG_OF_KOBJ) += kobj.o

obj-$(CONFIG_OF_DYNAMIC) += dynamic.o

obj-$(CONFIG_OF_FLATTREE) += fdt.o

obj-$(CONFIG_OF_EARLY_FLATTREE) += fdt_address.o

drivers/of/base.c

+0 −130
Original line number Diff line number Diff line
@@ -95,105 +95,6 @@ int __weak of_node_to_nid(struct device_node *np) 
}

#endif



#ifndef CONFIG_OF_DYNAMIC

static void of_node_release(struct kobject *kobj)

{

	/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */

}

#endif /* CONFIG_OF_DYNAMIC */



struct kobj_type of_node_ktype = {

	.release = of_node_release,

};



static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,

				struct bin_attribute *bin_attr, char *buf,

				loff_t offset, size_t count)

{

	struct property *pp = container_of(bin_attr, struct property, attr);

	return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);

}



/* always return newly allocated name, caller must free after use */

static const char *safe_name(struct kobject *kobj, const char *orig_name)

{

	const char *name = orig_name;

	struct kernfs_node *kn;

	int i = 0;



	/* don't be a hero. After 16 tries give up */

	while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {

		sysfs_put(kn);

		if (name != orig_name)

			kfree(name);

		name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);

	}



	if (name == orig_name) {

		name = kstrdup(orig_name, GFP_KERNEL);

	} else {

		pr_warn("Duplicate name in %s, renamed to \"%s\"\n",

			kobject_name(kobj), name);

	}

	return name;

}



int __of_add_property_sysfs(struct device_node *np, struct property *pp)

{

	int rc;



	/* Important: Don't leak passwords */

	bool secure = strncmp(pp->name, "security-", 9) == 0;



	if (!IS_ENABLED(CONFIG_SYSFS))

		return 0;



	if (!of_kset || !of_node_is_attached(np))

		return 0;



	sysfs_bin_attr_init(&pp->attr);

	pp->attr.attr.name = safe_name(&np->kobj, pp->name);

	pp->attr.attr.mode = secure ? 0400 : 0444;

	pp->attr.size = secure ? 0 : pp->length;

	pp->attr.read = of_node_property_read;



	rc = sysfs_create_bin_file(&np->kobj, &pp->attr);

	WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);

	return rc;

}



int __of_attach_node_sysfs(struct device_node *np)

{

	const char *name;

	struct kobject *parent;

	struct property *pp;

	int rc;



	if (!of_kset)

		return 0;



	np->kobj.kset = of_kset;

	if (!np->parent) {

		/* Nodes without parents are new top level trees */

		name = safe_name(&of_kset->kobj, "base");

		parent = NULL;

	} else {

		name = safe_name(&np->parent->kobj, kbasename(np->full_name));

		parent = &np->parent->kobj;

	}

	if (!name)

		return -ENOMEM;

	rc = kobject_add(&np->kobj, parent, "%s", name);

	kfree(name);

	if (rc)

		return rc;



	for_each_property_of_node(np, pp)

		__of_add_property_sysfs(np, pp);



	return 0;

}



void __init of_core_init(void)

{

	struct device_node *np;
@@ -1501,22 +1402,6 @@ int __of_remove_property(struct device_node *np, struct property *prop) 
	return 0;

}



void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)

{

	sysfs_remove_bin_file(&np->kobj, &prop->attr);

	kfree(prop->attr.attr.name);

}



void __of_remove_property_sysfs(struct device_node *np, struct property *prop)

{

	if (!IS_ENABLED(CONFIG_SYSFS))

		return;



	/* at early boot, bail here and defer setup to of_init() */

	if (of_kset && of_node_is_attached(np))

		__of_sysfs_remove_bin_file(np, prop);

}



/**

 * of_remove_property - Remove a property from a node.

 *
@@ -1576,21 +1461,6 @@ int __of_update_property(struct device_node *np, struct property *newprop, 
	return 0;

}



void __of_update_property_sysfs(struct device_node *np, struct property *newprop,

		struct property *oldprop)

{

	if (!IS_ENABLED(CONFIG_SYSFS))

		return;



	/* At early boot, bail out and defer setup to of_init() */

	if (!of_kset)

		return;



	if (oldprop)

		__of_sysfs_remove_bin_file(np, oldprop);

	__of_add_property_sysfs(np, newprop);

}



/*

 * of_update_property - Update a property in a node, if the property does

 * not exist, add it.

drivers/of/dynamic.c

+0 −22
Original line number Diff line number Diff line
@@ -48,28 +48,6 @@ void of_node_put(struct device_node *node) 
}

EXPORT_SYMBOL(of_node_put);



void __of_detach_node_sysfs(struct device_node *np)

{

	struct property *pp;



	if (!IS_ENABLED(CONFIG_SYSFS))

		return;



	BUG_ON(!of_node_is_initialized(np));

	if (!of_kset)

		return;



	/* only remove properties if on sysfs */

	if (of_node_is_attached(np)) {

		for_each_property_of_node(np, pp)

			__of_sysfs_remove_bin_file(np, pp);

		kobject_del(&np->kobj);

	}



	/* finally remove the kobj_init ref */

	of_node_put(np);

}



static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);



int of_reconfig_notifier_register(struct notifier_block *nb)

drivers/of/kobj.c

0 → 100644
+164 −0
Original line number Diff line number Diff line 
#include <linux/of.h>

#include <linux/slab.h>



#include "of_private.h"



/* true when node is initialized */

static int of_node_is_initialized(struct device_node *node)

{

	return node && node->kobj.state_initialized;

}



/* true when node is attached (i.e. present on sysfs) */

int of_node_is_attached(struct device_node *node)

{

	return node && node->kobj.state_in_sysfs;

}





#ifndef CONFIG_OF_DYNAMIC

static void of_node_release(struct kobject *kobj)

{

	/* Without CONFIG_OF_DYNAMIC, no nodes gets freed */

}

#endif /* CONFIG_OF_DYNAMIC */



struct kobj_type of_node_ktype = {

	.release = of_node_release,

};



static ssize_t of_node_property_read(struct file *filp, struct kobject *kobj,

				struct bin_attribute *bin_attr, char *buf,

				loff_t offset, size_t count)

{

	struct property *pp = container_of(bin_attr, struct property, attr);

	return memory_read_from_buffer(buf, count, &offset, pp->value, pp->length);

}



/* always return newly allocated name, caller must free after use */

static const char *safe_name(struct kobject *kobj, const char *orig_name)

{

	const char *name = orig_name;

	struct kernfs_node *kn;

	int i = 0;



	/* don't be a hero. After 16 tries give up */

	while (i < 16 && (kn = sysfs_get_dirent(kobj->sd, name))) {

		sysfs_put(kn);

		if (name != orig_name)

			kfree(name);

		name = kasprintf(GFP_KERNEL, "%s#%i", orig_name, ++i);

	}



	if (name == orig_name) {

		name = kstrdup(orig_name, GFP_KERNEL);

	} else {

		pr_warn("Duplicate name in %s, renamed to \"%s\"\n",

			kobject_name(kobj), name);

	}

	return name;

}



int __of_add_property_sysfs(struct device_node *np, struct property *pp)

{

	int rc;



	/* Important: Don't leak passwords */

	bool secure = strncmp(pp->name, "security-", 9) == 0;



	if (!IS_ENABLED(CONFIG_SYSFS))

		return 0;



	if (!of_kset || !of_node_is_attached(np))

		return 0;



	sysfs_bin_attr_init(&pp->attr);

	pp->attr.attr.name = safe_name(&np->kobj, pp->name);

	pp->attr.attr.mode = secure ? 0400 : 0444;

	pp->attr.size = secure ? 0 : pp->length;

	pp->attr.read = of_node_property_read;



	rc = sysfs_create_bin_file(&np->kobj, &pp->attr);

	WARN(rc, "error adding attribute %s to node %pOF\n", pp->name, np);

	return rc;

}



void __of_sysfs_remove_bin_file(struct device_node *np, struct property *prop)

{

	if (!IS_ENABLED(CONFIG_SYSFS))

		return;



	sysfs_remove_bin_file(&np->kobj, &prop->attr);

	kfree(prop->attr.attr.name);

}



void __of_remove_property_sysfs(struct device_node *np, struct property *prop)

{

	/* at early boot, bail here and defer setup to of_init() */

	if (of_kset && of_node_is_attached(np))

		__of_sysfs_remove_bin_file(np, prop);

}



void __of_update_property_sysfs(struct device_node *np, struct property *newprop,

		struct property *oldprop)

{

	/* At early boot, bail out and defer setup to of_init() */

	if (!of_kset)

		return;



	if (oldprop)

		__of_sysfs_remove_bin_file(np, oldprop);

	__of_add_property_sysfs(np, newprop);

}



int __of_attach_node_sysfs(struct device_node *np)

{

	const char *name;

	struct kobject *parent;

	struct property *pp;

	int rc;



	if (!of_kset)

		return 0;



	np->kobj.kset = of_kset;

	if (!np->parent) {

		/* Nodes without parents are new top level trees */

		name = safe_name(&of_kset->kobj, "base");

		parent = NULL;

	} else {

		name = safe_name(&np->parent->kobj, kbasename(np->full_name));

		parent = &np->parent->kobj;

	}

	if (!name)

		return -ENOMEM;

	rc = kobject_add(&np->kobj, parent, "%s", name);

	kfree(name);

	if (rc)

		return rc;



	for_each_property_of_node(np, pp)

		__of_add_property_sysfs(np, pp);



	return 0;

}



void __of_detach_node_sysfs(struct device_node *np)

{

	struct property *pp;



	BUG_ON(!of_node_is_initialized(np));

	if (!of_kset)

		return;



	/* only remove properties if on sysfs */

	if (of_node_is_attached(np)) {

		for_each_property_of_node(np, pp)

			__of_sysfs_remove_bin_file(np, pp);

		kobject_del(&np->kobj);

	}



	/* finally remove the kobj_init ref */

	of_node_put(np);

}