1 files changed, 441 insertions, 0 deletions
diff --git a/drivers/base/attribute_container.c b/drivers/base/attribute_container.c
new file mode 100644
index 000000000..20736aaa0
--- /dev/null
+++ b/drivers/base/attribute_container.c
@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * attribute_container.c - implementation of a simple container for classes
+ *
+ * Copyright (c) 2005 - James Bottomley <James.Bottomley@steeleye.com>
+ *
+ * The basic idea here is to enable a device to be attached to an
+ * aritrary numer of classes without having to allocate storage for them.
+ * Instead, the contained classes select the devices they need to attach
+ * to via a matching function.
+ */
+
+#include <linux/attribute_container.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+#include "base.h"
+
+/* This is a private structure used to tie the classdev and the
+ * container .. it should never be visible outside this file */
+struct internal_container {
+	struct klist_node node;
+	struct attribute_container *cont;
+	struct device classdev;
+};
+
+static void internal_container_klist_get(struct klist_node *n)
+{
+	struct internal_container *ic =
+		container_of(n, struct internal_container, node);
+	get_device(&ic->classdev);
+}
+
+static void internal_container_klist_put(struct klist_node *n)
+{
+	struct internal_container *ic =
+		container_of(n, struct internal_container, node);
+	put_device(&ic->classdev);
+}
+
+
+/**
+ * attribute_container_classdev_to_container - given a classdev, return the container
+ *
+ * @classdev: the class device created by attribute_container_add_device.
+ *
+ * Returns the container associated with this classdev.
+ */
+struct attribute_container *
+attribute_container_classdev_to_container(struct device *classdev)
+{
+	struct internal_container *ic =
+		container_of(classdev, struct internal_container, classdev);
+	return ic->cont;
+}
+EXPORT_SYMBOL_GPL(attribute_container_classdev_to_container);
+
+static LIST_HEAD(attribute_container_list);
+
+static DEFINE_MUTEX(attribute_container_mutex);
+
+/**
+ * attribute_container_register - register an attribute container
+ *
+ * @cont: The container to register.  This must be allocated by the
+ *        callee and should also be zeroed by it.
+ */
+int
+attribute_container_register(struct attribute_container *cont)
+{
+	INIT_LIST_HEAD(&cont->node);
+	klist_init(&cont->containers, internal_container_klist_get,
+		   internal_container_klist_put);
+
+	mutex_lock(&attribute_container_mutex);
+	list_add_tail(&cont->node, &attribute_container_list);
+	mutex_unlock(&attribute_container_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(attribute_container_register);
+
+/**
+ * attribute_container_unregister - remove a container registration
+ *
+ * @cont: previously registered container to remove
+ */
+int
+attribute_container_unregister(struct attribute_container *cont)
+{
+	int retval = -EBUSY;
+
+	mutex_lock(&attribute_container_mutex);
+	spin_lock(&cont->containers.k_lock);
+	if (!list_empty(&cont->containers.k_list))
+		goto out;
+	retval = 0;
+	list_del(&cont->node);
+ out:
+	spin_unlock(&cont->containers.k_lock);
+	mutex_unlock(&attribute_container_mutex);
+	return retval;
+
+}
+EXPORT_SYMBOL_GPL(attribute_container_unregister);
+
+/* private function used as class release */
+static void attribute_container_release(struct device *classdev)
+{
+	struct internal_container *ic
+		= container_of(classdev, struct internal_container, classdev);
+	struct device *dev = classdev->parent;
+
+	kfree(ic);
+	put_device(dev);
+}
+
+/**
+ * attribute_container_add_device - see if any container is interested in dev
+ *
+ * @dev: device to add attributes to
+ * @fn:	 function to trigger addition of class device.
+ *
+ * This function allocates storage for the class device(s) to be
+ * attached to dev (one for each matching attribute_container).  If no
+ * fn is provided, the code will simply register the class device via
+ * device_add.  If a function is provided, it is expected to add
+ * the class device at the appropriate time.  One of the things that
+ * might be necessary is to allocate and initialise the classdev and
+ * then add it a later time.  To do this, call this routine for
+ * allocation and initialisation and then use
+ * attribute_container_device_trigger() to call device_add() on
+ * it.  Note: after this, the class device contains a reference to dev
+ * which is not relinquished until the release of the classdev.
+ */
+void
+attribute_container_add_device(struct device *dev,
+			       int (*fn)(struct attribute_container *,
+					 struct device *,
+					 struct device *))
+{
+	struct attribute_container *cont;
+
+	mutex_lock(&attribute_container_mutex);
+	list_for_each_entry(cont, &attribute_container_list, node) {
+		struct internal_container *ic;
+
+		if (attribute_container_no_classdevs(cont))
+			continue;
+
+		if (!cont->match(cont, dev))
+			continue;
+
+		ic = kzalloc(sizeof(*ic), GFP_KERNEL);
+		if (!ic) {
+			dev_err(dev, "failed to allocate class container\n");
+			continue;
+		}
+
+		ic->cont = cont;
+		device_initialize(&ic->classdev);
+		ic->classdev.parent = get_device(dev);
+		ic->classdev.class = cont->class;
+		cont->class->dev_release = attribute_container_release;
+		dev_set_name(&ic->classdev, "%s", dev_name(dev));
+		if (fn)
+			fn(cont, dev, &ic->classdev);
+		else
+			attribute_container_add_class_device(&ic->classdev);
+		klist_add_tail(&ic->node, &cont->containers);
+	}
+	mutex_unlock(&attribute_container_mutex);
+}
+
+/* FIXME: can't break out of this unless klist_iter_exit is also
+ * called before doing the break
+ */
+#define klist_for_each_entry(pos, head, member, iter) \
+	for (klist_iter_init(head, iter); (pos = ({ \
+		struct klist_node *n = klist_next(iter); \
+		n ? container_of(n, typeof(*pos), member) : \
+			({ klist_iter_exit(iter) ; NULL; }); \
+	})) != NULL;)
+
+
+/**
+ * attribute_container_remove_device - make device eligible for removal.
+ *
+ * @dev:  The generic device
+ * @fn:	  A function to call to remove the device
+ *
+ * This routine triggers device removal.  If fn is NULL, then it is
+ * simply done via device_unregister (note that if something
+ * still has a reference to the classdev, then the memory occupied
+ * will not be freed until the classdev is released).  If you want a
+ * two phase release: remove from visibility and then delete the
+ * device, then you should use this routine with a fn that calls
+ * device_del() and then use attribute_container_device_trigger()
+ * to do the final put on the classdev.
+ */
+void
+attribute_container_remove_device(struct device *dev,
+				  void (*fn)(struct attribute_container *,
+					     struct device *,
+					     struct device *))
+{
+	struct attribute_container *cont;
+
+	mutex_lock(&attribute_container_mutex);
+	list_for_each_entry(cont, &attribute_container_list, node) {
+		struct internal_container *ic;
+		struct klist_iter iter;
+
+		if (attribute_container_no_classdevs(cont))
+			continue;
+
+		if (!cont->match(cont, dev))
+			continue;
+
+		klist_for_each_entry(ic, &cont->containers, node, &iter) {
+			if (dev != ic->classdev.parent)
+				continue;
+			klist_del(&ic->node);
+			if (fn)
+				fn(cont, dev, &ic->classdev);
+			else {
+				attribute_container_remove_attrs(&ic->classdev);
+				device_unregister(&ic->classdev);
+			}
+		}
+	}
+	mutex_unlock(&attribute_container_mutex);
+}
+
+/**
+ * attribute_container_device_trigger - execute a trigger for each matching classdev
+ *
+ * @dev:  The generic device to run the trigger for
+ * @fn	  the function to execute for each classdev.
+ *
+ * This function is for executing a trigger when you need to know both
+ * the container and the classdev.  If you only care about the
+ * container, then use attribute_container_trigger() instead.
+ */
+void
+attribute_container_device_trigger(struct device *dev,
+				   int (*fn)(struct attribute_container *,
+					     struct device *,
+					     struct device *))
+{
+	struct attribute_container *cont;
+
+	mutex_lock(&attribute_container_mutex);
+	list_for_each_entry(cont, &attribute_container_list, node) {
+		struct internal_container *ic;
+		struct klist_iter iter;
+
+		if (!cont->match(cont, dev))
+			continue;
+
+		if (attribute_container_no_classdevs(cont)) {
+			fn(cont, dev, NULL);
+			continue;
+		}
+
+		klist_for_each_entry(ic, &cont->containers, node, &iter) {
+			if (dev == ic->classdev.parent)
+				fn(cont, dev, &ic->classdev);
+		}
+	}
+	mutex_unlock(&attribute_container_mutex);
+}
+
+/**
+ * attribute_container_trigger - trigger a function for each matching container
+ *
+ * @dev:  The generic device to activate the trigger for
+ * @fn:	  the function to trigger
+ *
+ * This routine triggers a function that only needs to know the
+ * matching containers (not the classdev) associated with a device.
+ * It is more lightweight than attribute_container_device_trigger, so
+ * should be used in preference unless the triggering function
+ * actually needs to know the classdev.
+ */
+void
+attribute_container_trigger(struct device *dev,
+			    int (*fn)(struct attribute_container *,
+				      struct device *))
+{
+	struct attribute_container *cont;
+
+	mutex_lock(&attribute_container_mutex);
+	list_for_each_entry(cont, &attribute_container_list, node) {
+		if (cont->match(cont, dev))
+			fn(cont, dev);
+	}
+	mutex_unlock(&attribute_container_mutex);
+}
+
+/**
+ * attribute_container_add_attrs - add attributes
+ *
+ * @classdev: The class device
+ *
+ * This simply creates all the class device sysfs files from the
+ * attributes listed in the container
+ */
+int
+attribute_container_add_attrs(struct device *classdev)
+{
+	struct attribute_container *cont =
+		attribute_container_classdev_to_container(classdev);
+	struct device_attribute **attrs = cont->attrs;
+	int i, error;
+
+	BUG_ON(attrs && cont->grp);
+
+	if (!attrs && !cont->grp)
+		return 0;
+
+	if (cont->grp)
+		return sysfs_create_group(&classdev->kobj, cont->grp);
+
+	for (i = 0; attrs[i]; i++) {
+		sysfs_attr_init(&attrs[i]->attr);
+		error = device_create_file(classdev, attrs[i]);
+		if (error)
+			return error;
+	}
+
+	return 0;
+}
+
+/**
+ * attribute_container_add_class_device - same function as device_add
+ *
+ * @classdev:	the class device to add
+ *
+ * This performs essentially the same function as device_add except for
+ * attribute containers, namely add the classdev to the system and then
+ * create the attribute files
+ */
+int
+attribute_container_add_class_device(struct device *classdev)
+{
+	int error = device_add(classdev);
+
+	if (error)
+		return error;
+	return attribute_container_add_attrs(classdev);
+}
+
+/**
+ * attribute_container_add_class_device_adapter - simple adapter for triggers
+ *
+ * This function is identical to attribute_container_add_class_device except
+ * that it is designed to be called from the triggers
+ */
+int
+attribute_container_add_class_device_adapter(struct attribute_container *cont,
+					     struct device *dev,
+					     struct device *classdev)
+{
+	return attribute_container_add_class_device(classdev);
+}
+
+/**
+ * attribute_container_remove_attrs - remove any attribute files
+ *
+ * @classdev: The class device to remove the files from
+ *
+ */
+void
+attribute_container_remove_attrs(struct device *classdev)
+{
+	struct attribute_container *cont =
+		attribute_container_classdev_to_container(classdev);
+	struct device_attribute **attrs = cont->attrs;
+	int i;
+
+	if (!attrs && !cont->grp)
+		return;
+
+	if (cont->grp) {
+		sysfs_remove_group(&classdev->kobj, cont->grp);
+		return ;
+	}
+
+	for (i = 0; attrs[i]; i++)
+		device_remove_file(classdev, attrs[i]);
+}
+
+/**
+ * attribute_container_class_device_del - equivalent of class_device_del
+ *
+ * @classdev: the class device
+ *
+ * This function simply removes all the attribute files and then calls
+ * device_del.
+ */
+void
+attribute_container_class_device_del(struct device *classdev)
+{
+	attribute_container_remove_attrs(classdev);
+	device_del(classdev);
+}
+
+/**
+ * attribute_container_find_class_device - find the corresponding class_device
+ *
+ * @cont:	the container
+ * @dev:	the generic device
+ *
+ * Looks up the device in the container's list of class devices and returns
+ * the corresponding class_device.
+ */
+struct device *
+attribute_container_find_class_device(struct attribute_container *cont,
+				      struct device *dev)
+{
+	struct device *cdev = NULL;
+	struct internal_container *ic;
+	struct klist_iter iter;
+
+	klist_for_each_entry(ic, &cont->containers, node, &iter) {
+		if (ic->classdev.parent == dev) {
+			cdev = &ic->classdev;
+			/* FIXME: must exit iterator then break */
+			klist_iter_exit(&iter);
+			break;
+		}
+	}
+
+	return cdev;
+}
+EXPORT_SYMBOL_GPL(attribute_container_find_class_device);