[RFC PATCH 2/5] Merge dynamic OF code to of_dynamic.c
Nathan Fontenot
nfont at austin.ibm.com
Thu Nov 5 09:16:38 EST 2009
Creation of the OF dynamic device tree update code in drivers/of. This
merges the common device tree updating routines to add/remove nodes and
properties from powerpc and microblaze. All of the new code is conditional
based on a new OF_DYNAMIC config option.
There are two updates to the code. First, the routines to update properties
are re-named from prom_* to of_*. This seems correct as the routines no longer
reside in prom.c files. Second, the addition of a notifier chain for when
nodes are added removed from the device tree. This is a feature that currently
exists in powerpc.
Signed-off-by: Nathan Fontenot <nfont at austin.ibm.com>
---
Index: linux-next/drivers/of/of_dynamic.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-next/drivers/of/of_dynamic.c 2009-11-04 14:45:11.000000000 -0600
@@ -0,0 +1,387 @@
+/*
+ * Definitions for talking to the Open Firmware PROM on
+ * Power Macintosh and other computers.
+ *
+ * Copyright (C) 1996-2005 Paul Mackerras.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/of.h>
+
+BLOCKING_NOTIFIER_HEAD(of_update_chain);
+
+/**
+ * of_node_get - Increment refcount of a node
+ * @node: Node to inc refcount, NULL is supported to
+ * simplify writing of callers
+ *
+ * Returns node.
+ */
+struct device_node *of_node_get(struct device_node *node)
+{
+ if (node)
+ kref_get(&node->kref);
+ return node;
+}
+EXPORT_SYMBOL(of_node_get);
+
+static inline struct device_node *kref_to_device_node(struct kref *kref)
+{
+ return container_of(kref, struct device_node, kref);
+}
+
+/**
+ * of_node_release - release a dynamically allocated node
+ * @kref: kref element of the node to be released
+ *
+ * In of_node_put() this function is passed to kref_put()
+ * as the destructor.
+ */
+static void of_node_release(struct kref *kref)
+{
+ struct device_node *node = kref_to_device_node(kref);
+ struct property *prop = node->properties;
+
+ /* We should never be releasing nodes that haven't been detached. */
+ if (!of_node_check_flag(node, OF_DETACHED)) {
+ printk(KERN_WARNING "Bad of_node_put() on %s\n",
+ node->full_name);
+ dump_stack();
+ kref_init(&node->kref);
+ return;
+ }
+
+ if (!of_node_check_flag(node, OF_DYNAMIC))
+ return;
+
+ while (prop) {
+ struct property *next = prop->next;
+ kfree(prop->name);
+ kfree(prop->value);
+ kfree(prop);
+ prop = next;
+
+ if (!prop) {
+ prop = node->deadprops;
+ node->deadprops = NULL;
+ }
+ }
+ kfree(node->full_name);
+ kfree(node->data);
+ kfree(node);
+}
+
+/**
+ * of_node_put - Decrement refcount of a node
+ * @node: Node to dec refcount, NULL is supported to
+ * simplify writing of callers
+ *
+ */
+void of_node_put(struct device_node *node)
+{
+ if (node)
+ kref_put(&node->kref, of_node_release);
+}
+EXPORT_SYMBOL(of_node_put);
+
+static struct device_node *of_derive_parent(char *path)
+{
+ struct device_node *parent = NULL;
+ char *parent_path = "/";
+ size_t parent_path_len = strrchr(path, '/') - path + 1;
+
+ /* reject if path is "/" */
+ if (!strcmp(path, "/"))
+ return ERR_PTR(-EINVAL);
+
+ if (strrchr(path, '/') != path) {
+ parent_path = kmalloc(parent_path_len, GFP_KERNEL);
+ if (!parent_path)
+ return ERR_PTR(-ENOMEM);
+ strlcpy(parent_path, path, parent_path_len);
+ }
+
+ parent = of_find_node_by_path(parent_path);
+ if (!parent)
+ return ERR_PTR(-EINVAL);
+
+ if (strcmp(parent_path, "/"))
+ kfree(parent_path);
+ return parent;
+}
+
+static int of_attach_one_node(struct device_node *np)
+{
+ struct proc_dir_entry *ent;
+ unsigned long flags;
+ int rc;
+
+ of_node_set_flag(np, OF_DYNAMIC);
+ kref_init(&np->kref);
+
+ np->parent = of_derive_parent(np->full_name);
+ if (IS_ERR(np->parent))
+ return PTR_ERR(np->parent);
+
+ rc = of_update_notifier_call(OF_ATTACH_NODE, np);
+ if (rc == NOTIFY_BAD) {
+ printk(KERN_ERR "Failed to add device node %s\n",
+ np->full_name);
+ return -ENOMEM; /* For now, safe to assume kmalloc failure */
+ }
+
+ write_lock_irqsave(&devtree_lock, flags);
+ np->sibling = np->parent->child;
+ np->allnext = allnodes;
+ np->parent->child = np;
+
+ allnodes = np;
+ write_unlock_irqrestore(&devtree_lock, flags);
+
+#ifdef CONFIG_PROC_DEVICETREE
+ ent = proc_mkdir(strrchr(np->full_name, '/') + 1, np->parent->pde);
+ if (ent)
+ proc_device_tree_add_node(np, ent);
+#endif
+
+ of_node_put(np->parent);
+ return 0;
+}
+
+int of_attach_node(struct device_node *np)
+{
+ struct device_node *child = np->child;
+ struct device_node *sibling = np->sibling;
+ int rc;
+
+ np->child = NULL;
+ np->sibling = NULL;
+ np->parent = NULL;
+
+ rc = of_attach_one_node(np);
+ if (rc)
+ return rc;
+
+ if (child) {
+ rc = of_attach_node(child);
+ if (rc)
+ return rc;
+ }
+
+ if (sibling)
+ rc = of_attach_node(sibling);
+
+ return rc;
+}
+EXPORT_SYMBOL(of_attach_node);
+
+/*
+ * "Unplug" a node from the device tree. The caller must hold
+ * a reference to the node. The memory associated with the node
+ * is not freed until its refcount goes to zero.
+ */
+static int of_detach_one_node(struct device_node *np)
+{
+ struct device_node *parent = np->parent;
+ struct property *prop = np->properties;
+ unsigned long flags;
+
+ if (!parent)
+ return -1;
+
+#ifdef CONFIG_PROC_DEVICETREE
+ while (prop) {
+ remove_proc_entry(prop->name, np->pde);
+ prop = prop->next;
+ }
+
+ if (np->pde)
+ remove_proc_entry(np->pde->name, parent->pde);
+#endif
+
+ of_update_notifier_call(OF_DETACH_NODE, np);
+
+ write_lock_irqsave(&devtree_lock, flags);
+
+ if (allnodes == np)
+ allnodes = np->allnext;
+ else {
+ struct device_node *prev;
+ for (prev = allnodes;
+ prev->allnext != np;
+ prev = prev->allnext)
+ ;
+ prev->allnext = np->allnext;
+ }
+
+ if (parent->child == np)
+ parent->child = np->sibling;
+ else {
+ struct device_node *prevsib;
+ for (prevsib = np->parent->child;
+ prevsib->sibling != np;
+ prevsib = prevsib->sibling)
+ ;
+ prevsib->sibling = np->sibling;
+ }
+
+ of_node_set_flag(np, OF_DETACHED);
+ write_unlock_irqrestore(&devtree_lock, flags);
+ of_node_put(np);
+ return 0;
+}
+
+static int _of_detach_node(struct device_node *np)
+{
+ int rc;
+
+ if (np->child) {
+ rc = _of_detach_node(np->child);
+ if (rc)
+ return rc;
+ }
+
+ if (np->sibling) {
+ rc = _of_detach_node(np->sibling);
+ if (rc)
+ return rc;
+ }
+
+ rc = of_detach_one_node(np);
+ return rc;
+}
+
+int of_detach_node(struct device_node *np)
+{
+ int rc;
+
+ if (np->child) {
+ rc = _of_detach_node(np->child);
+ if (rc)
+ return rc;
+ }
+
+ rc = of_detach_one_node(np);
+ return rc;
+}
+EXPORT_SYMBOL(of_detach_node);
+
+/*
+ * Add a property to a node
+ */
+int of_property_attach(struct device_node *np, struct property* prop)
+{
+ struct property **next;
+ unsigned long flags;
+
+ prop->next = NULL;
+
+ write_lock_irqsave(&devtree_lock, flags);
+ next = &np->properties;
+ while (*next) {
+ if (strcmp(prop->name, (*next)->name) == 0) {
+ /* duplicate ! don't insert it */
+ write_unlock_irqrestore(&devtree_lock, flags);
+ return -1;
+ }
+ next = &(*next)->next;
+ }
+ *next = prop;
+ write_unlock_irqrestore(&devtree_lock, flags);
+
+#ifdef CONFIG_PROC_DEVICETREE
+ /* try to add to proc as well if it was initialized */
+ if (np->pde)
+ proc_device_tree_add_prop(np->pde, prop);
+#endif /* CONFIG_PROC_DEVICETREE */
+
+ return 0;
+}
+EXPORT_SYMBOL(of_property_attach);
+
+/*
+ * Remove a property from a node. Note that we don't actually
+ * remove it, since we have given out who-knows-how-many pointers
+ * to the data using get-property. Instead we just move the property
+ * to the "dead properties" list, so it won't be found any more.
+ */
+int of_property_detach(struct device_node *np, struct property *prop)
+{
+ struct property **next;
+ unsigned long flags;
+ int found = 0;
+
+ write_lock_irqsave(&devtree_lock, flags);
+ next = &np->properties;
+ while (*next) {
+ if (*next == prop) {
+ /* found the node */
+ *next = prop->next;
+ prop->next = np->deadprops;
+ np->deadprops = prop;
+ found = 1;
+ break;
+ }
+ next = &(*next)->next;
+ }
+ write_unlock_irqrestore(&devtree_lock, flags);
+
+ if (!found)
+ return -ENODEV;
+
+#ifdef CONFIG_PROC_DEVICETREE
+ /* try to remove the proc node as well */
+ if (np->pde)
+ proc_device_tree_remove_prop(np->pde, prop);
+#endif /* CONFIG_PROC_DEVICETREE */
+
+ return 0;
+}
+EXPORT_SYMBOL(of_property_detach);
+
+/*
+ * Update a property in a node. Note that we don't actually
+ * remove it, since we have given out who-knows-how-many pointers
+ * to the data using get-property. Instead we just move the property
+ * to the "dead properties" list, and add the new property to the
+ * property list
+ */
+int of_property_update(struct device_node *np, struct property *newprop,
+ struct property *oldprop)
+{
+ struct property **next;
+ unsigned long flags;
+ int found = 0;
+
+ write_lock_irqsave(&devtree_lock, flags);
+ next = &np->properties;
+ while (*next) {
+ if (*next == oldprop) {
+ /* found the node */
+ newprop->next = oldprop->next;
+ *next = newprop;
+ oldprop->next = np->deadprops;
+ np->deadprops = oldprop;
+ found = 1;
+ break;
+ }
+ next = &(*next)->next;
+ }
+ write_unlock_irqrestore(&devtree_lock, flags);
+
+ if (!found)
+ return -ENODEV;
+
+#ifdef CONFIG_PROC_DEVICETREE
+ /* try to add to proc as well if it was initialized */
+ if (np->pde)
+ proc_device_tree_update_prop(np->pde, newprop, oldprop);
+#endif /* CONFIG_PROC_DEVICETREE */
+
+ return 0;
+}
+EXPORT_SYMBOL(of_property_update);
Index: linux-next/include/linux/of.h
===================================================================
--- linux-next.orig/include/linux/of.h 2009-11-03 11:18:08.000000000 -0600
+++ linux-next/include/linux/of.h 2009-11-03 13:42:38.000000000 -0600
@@ -20,6 +20,8 @@
#include <linux/kref.h>
#include <linux/mod_devicetable.h>
#include <linux/spinlock.h>
+#include <linux/proc_fs.h>
+#include <linux/notifier.h>
typedef u32 phandle;
typedef u32 ihandle;
@@ -191,4 +193,34 @@
const char *list_name, const char *cells_name, int index,
struct device_node **out_node, const void **out_args);
+#ifdef CONFIG_OF_DYNAMIC
+extern int of_attach_node(struct device_node *np);
+extern int of_detach_node(struct device_node *np);
+extern int of_property_attach(struct device_node *np, struct property *prop);
+extern int of_property_detach(struct device_node *np, struct property *prop);
+extern int of_property_update(struct device_node *np, struct property *newprop,
+ struct property *oldprop);
+
+/* Dynamic Update Notifier Chain */
+extern struct blocking_notifier_head of_update_chain;
+
+#define OF_ATTACH_NODE 1
+#define OF_DETACH_NODE 2
+
+static inline int of_update_notifier_register(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_register(&of_update_chain, nb);
+}
+
+static inline int of_update_notifier_unregister(struct notifier_block *nb)
+{
+ return blocking_notifier_chain_unregister(&of_update_chain, nb);
+}
+
+static inline int of_update_notifier_call(unsigned int value, void *data)
+{
+ return blocking_notifier_call_chain(&of_update_chain, value, data);
+}
+#endif /* CONFIG_OF_DYNAMIC */
+
#endif /* _LINUX_OF_H */
Index: linux-next/drivers/of/Makefile
===================================================================
--- linux-next.orig/drivers/of/Makefile 2009-11-03 11:18:08.000000000 -0600
+++ linux-next/drivers/of/Makefile 2009-11-03 13:42:35.000000000 -0600
@@ -1,6 +1,7 @@
obj-y = base.o
-obj-$(CONFIG_OF_DEVICE) += device.o platform.o
-obj-$(CONFIG_OF_GPIO) += gpio.o
-obj-$(CONFIG_OF_I2C) += of_i2c.o
-obj-$(CONFIG_OF_SPI) += of_spi.o
-obj-$(CONFIG_OF_MDIO) += of_mdio.o
+obj-$(CONFIG_OF_DEVICE) += device.o platform.o
+obj-$(CONFIG_OF_GPIO) += gpio.o
+obj-$(CONFIG_OF_I2C) += of_i2c.o
+obj-$(CONFIG_OF_SPI) += of_spi.o
+obj-$(CONFIG_OF_MDIO) += of_mdio.o
+obj-$(CONFIG_OF_DYNAMIC) += of_dynamic.o
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