powerpc+of: Add of node/property notification chain for adds and removes

This patch moves the notification chain for updates to the device tree
from the powerpc/pseries code to the base OF code. This makes this
functionality available to all architectures.

Additionally the notification chain is updated to allow notifications
for property add/remove/update. To make this work a pointer to a new
struct (of_prop_reconfig) is passed to the routines in the notification chain.
The of_prop_reconfig property contains a pointer to the node containing the
property and a pointer to the property itself. In the case of property
updates, the property pointer refers to the new property.

Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

12 files changed, 163 insertions, 154 deletions

diff --git a/arch/powerpc/include/asm/pSeries_reconfig.h b/arch/powerpc/include/asm/pSeries_reconfig.h
index c07edfe98b98..adc00d2e75b0 100644
--- a/arch/powerpc/include/asm/pSeries_reconfig.h
+++ b/arch/powerpc/include/asm/pSeries_reconfig.h
@@ -2,43 +2,11 @@
 #define _PPC64_PSERIES_RECONFIG_H
 #ifdef __KERNEL__
 
-#include <linux/notifier.h>
-
-/*
- * Use this API if your code needs to know about OF device nodes being
- * added or removed on pSeries systems.
- */
-
-#define PSERIES_RECONFIG_ADD            0x0001
-#define PSERIES_RECONFIG_REMOVE         0x0002
-#define PSERIES_DRCONF_MEM_ADD          0x0003
-#define PSERIES_DRCONF_MEM_REMOVE       0x0004
-#define PSERIES_UPDATE_PROPERTY         0x0005
-
-/**
- * pSeries_reconfig_notify - Notifier value structure for OFDT property updates
- *
- * @node: Device tree node which owns the property being updated
- * @property: Updated property
- */
-struct pSeries_reconfig_prop_update {
-        struct device_node *node;
-        struct property *property;
-};
-
 #ifdef CONFIG_PPC_PSERIES
-extern int pSeries_reconfig_notifier_register(struct notifier_block *);
-extern void pSeries_reconfig_notifier_unregister(struct notifier_block *);
-extern int pSeries_reconfig_notify(unsigned long action, void *p);
 /* Not the best place to put this, will be fixed when we move some
  * of the rtas suspend-me stuff to pseries */
 extern void pSeries_coalesce_init(void);
 #else /* !CONFIG_PPC_PSERIES */
-static inline int pSeries_reconfig_notifier_register(struct notifier_block *nb)
-{
-        return 0;
-}
-static inline void pSeries_reconfig_notifier_unregister(struct notifier_block *nb) { }
 static inline void pSeries_coalesce_init(void) { }
 #endif /* CONFIG_PPC_PSERIES */
 
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 37725e86651e..6feb60c3c6e3 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -32,6 +32,7 @@
 #include <linux/debugfs.h>
 #include <linux/irq.h>
 #include <linux/memblock.h>
+#include <linux/of.h>
 
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -49,7 +50,6 @@
 #include <asm/btext.h>
 #include <asm/sections.h>
 #include <asm/machdep.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/pci-bridge.h>
 #include <asm/kexec.h>
 #include <asm/opal.h>
@@ -802,7 +802,7 @@ static int prom_reconfig_notifier(struct notifier_block *nb,
         int err;
 
         switch (action) {
-        case PSERIES_RECONFIG_ADD:
+        case OF_RECONFIG_ATTACH_NODE:
                 err = of_finish_dynamic_node(node);
                 if (err < 0)
                         printk(KERN_ERR "finish_node returned %d\n", err);
@@ -821,7 +821,7 @@ static struct notifier_block prom_reconfig_nb = {
 
 static int __init prom_reconfig_setup(void)
 {
-        return pSeries_reconfig_notifier_register(&prom_reconfig_nb);
+        return of_reconfig_notifier_register(&prom_reconfig_nb);
 }
 __initcall(prom_reconfig_setup);
 #endif
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index e36789bd4e6c..a1a7b9a67ffd 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -16,13 +16,13 @@
 #include <linux/spinlock.h>
 #include <linux/cpu.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 #include "offline_states.h"
 
 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/uaccess.h>
 #include <asm/rtas.h>
-#include <asm/pSeries_reconfig.h>
 
 struct cc_workarea {
         u32     drc_index;
@@ -262,24 +262,26 @@ int dlpar_attach_node(struct device_node *dn)
         if (!dn->parent)
                 return -ENOMEM;
 
-        rc = pSeries_reconfig_notify(PSERIES_RECONFIG_ADD, dn);
+        rc = of_attach_node(dn);
         if (rc) {
                 printk(KERN_ERR "Failed to add device node %s\n",
                        dn->full_name);
                 return rc;
         }
 
-        of_attach_node(dn);
         of_node_put(dn->parent);
         return 0;
 }
 
 int dlpar_detach_node(struct device_node *dn)
 {
-        pSeries_reconfig_notify(PSERIES_RECONFIG_REMOVE, dn);
-        of_detach_node(dn);
-        of_node_put(dn); /* Must decrement the refcount */
+        int rc;
+
+        rc = of_detach_node(dn);
+        if (rc)
+                return rc;
 
+        of_node_put(dn); /* Must decrement the refcount */
         return 0;
 }
 
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 64c97d8ac0c5..a38956269fbf 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -23,12 +23,12 @@
 #include <linux/delay.h>
 #include <linux/sched.h>        /* for idle_task_exit */
 #include <linux/cpu.h>
+#include <linux/of.h>
 #include <asm/prom.h>
 #include <asm/rtas.h>
 #include <asm/firmware.h>
 #include <asm/machdep.h>
 #include <asm/vdso_datapage.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/xics.h>
 #include "plpar_wrappers.h"
 #include "offline_states.h"
@@ -333,10 +333,10 @@ static int pseries_smp_notifier(struct notifier_block *nb,
         int err = 0;
 
         switch (action) {
-        case PSERIES_RECONFIG_ADD:
+        case OF_RECONFIG_ATTACH_NODE:
                 err = pseries_add_processor(node);
                 break;
-        case PSERIES_RECONFIG_REMOVE:
+        case OF_RECONFIG_DETACH_NODE:
                 pseries_remove_processor(node);
                 break;
         }
@@ -399,7 +399,7 @@ static int __init pseries_cpu_hotplug_init(void)
 
         /* Processors can be added/removed only on LPAR */
         if (firmware_has_feature(FW_FEATURE_LPAR)) {
-                pSeries_reconfig_notifier_register(&pseries_smp_nb);
+                of_reconfig_notifier_register(&pseries_smp_nb);
                 cpu_maps_update_begin();
                 if (cede_offline_enabled && parse_cede_parameters() == 0) {
                         default_offline_state = CPU_STATE_INACTIVE;
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index ecdb0a6b3171..2372c609fa2b 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -16,7 +16,6 @@
 
 #include <asm/firmware.h>
 #include <asm/machdep.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/sparsemem.h>
 
 static unsigned long get_memblock_size(void)
@@ -187,42 +186,69 @@ static int pseries_add_memory(struct device_node *np)
         return (ret < 0) ? -EINVAL : 0;
 }
 
-static int pseries_drconf_memory(unsigned long *base, unsigned int action)
+static int pseries_update_drconf_memory(struct of_prop_reconfig *pr)
 {
+        struct of_drconf_cell *new_drmem, *old_drmem;
         unsigned long memblock_size;
-        int rc;
+        u32 entries;
+        u32 *p;
+        int i, rc = -EINVAL;
 
         memblock_size = get_memblock_size();
         if (!memblock_size)
                 return -EINVAL;
 
-        if (action == PSERIES_DRCONF_MEM_ADD) {
-                rc = memblock_add(*base, memblock_size);
-                rc = (rc < 0) ? -EINVAL : 0;
-        } else if (action == PSERIES_DRCONF_MEM_REMOVE) {
-                rc = pseries_remove_memblock(*base, memblock_size);
-        } else {
-                rc = -EINVAL;
+        p = (u32 *)of_get_property(pr->dn, "ibm,dynamic-memory", NULL);
+        if (!p)
+                return -EINVAL;
+
+        /* The first int of the property is the number of lmb's described
+         * by the property. This is followed by an array of of_drconf_cell
+         * entries. Get the niumber of entries and skip to the array of
+         * of_drconf_cell's.
+         */
+        entries = *p++;
+        old_drmem = (struct of_drconf_cell *)p;
+
+        p = (u32 *)pr->prop->value;
+        p++;
+        new_drmem = (struct of_drconf_cell *)p;
+
+        for (i = 0; i < entries; i++) {
+                if ((old_drmem[i].flags & DRCONF_MEM_ASSIGNED) &&
+                    (!(new_drmem[i].flags & DRCONF_MEM_ASSIGNED))) {
+                        rc = pseries_remove_memblock(old_drmem[i].base_addr,
+                                                     memblock_size);
+                        break;
+                } else if ((!(old_drmem[i].flags & DRCONF_MEM_ASSIGNED)) &&
+                           (new_drmem[i].flags & DRCONF_MEM_ASSIGNED)) {
+                        rc = memblock_add(old_drmem[i].base_addr,
+                                          memblock_size);
+                        rc = (rc < 0) ? -EINVAL : 0;
+                        break;
+                }
         }
 
         return rc;
 }
 
 static int pseries_memory_notifier(struct notifier_block *nb,
-                                unsigned long action, void *node)
+                                   unsigned long action, void *node)
 {
+        struct of_prop_reconfig *pr;
         int err = 0;
 
         switch (action) {
-        case PSERIES_RECONFIG_ADD:
+        case OF_RECONFIG_ATTACH_NODE:
                 err = pseries_add_memory(node);
                 break;
-        case PSERIES_RECONFIG_REMOVE:
+        case OF_RECONFIG_DETACH_NODE:
                 err = pseries_remove_memory(node);
                 break;
-        case PSERIES_DRCONF_MEM_ADD:
-        case PSERIES_DRCONF_MEM_REMOVE:
-                err = pseries_drconf_memory(node, action);
+        case OF_RECONFIG_UPDATE_PROPERTY:
+                pr = (struct of_prop_reconfig *)node;
+                if (!strcmp(pr->prop->name, "ibm,dynamic-memory"))
+                        err = pseries_update_drconf_memory(pr);
                 break;
         }
         return notifier_from_errno(err);
@@ -235,7 +261,7 @@ static struct notifier_block pseries_mem_nb = {
 static int __init pseries_memory_hotplug_init(void)
 {
         if (firmware_has_feature(FW_FEATURE_LPAR))
-                pSeries_reconfig_notifier_register(&pseries_mem_nb);
+                of_reconfig_notifier_register(&pseries_mem_nb);
 
         return 0;
 }
diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 6153eea27ce7..da5594c441e4 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -36,13 +36,13 @@
 #include <linux/dma-mapping.h>
 #include <linux/crash_dump.h>
 #include <linux/memory.h>
+#include <linux/of.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/rtas.h>
 #include <asm/iommu.h>
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/firmware.h>
 #include <asm/tce.h>
 #include <asm/ppc-pci.h>
@@ -1294,7 +1294,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti
         struct direct_window *window;
 
         switch (action) {
-        case PSERIES_RECONFIG_REMOVE:
+        case OF_RECONFIG_DETACH_NODE:
                 if (pci && pci->iommu_table)
                         iommu_free_table(pci->iommu_table, np->full_name);
 
@@ -1357,7 +1357,7 @@ void iommu_init_early_pSeries(void)
         }
 
 
-        pSeries_reconfig_notifier_register(&iommu_reconfig_nb);
+        of_reconfig_notifier_register(&iommu_reconfig_nb);
         register_memory_notifier(&iommu_mem_nb);
 
         set_pci_dma_ops(&dma_iommu_ops);
diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c
index f99f1ca8035b..720a0cc2e69f 100644
--- a/arch/powerpc/platforms/pseries/reconfig.c
+++ b/arch/powerpc/platforms/pseries/reconfig.c
@@ -16,11 +16,11 @@
 #include <linux/notifier.h>
 #include <linux/proc_fs.h>
 #include <linux/slab.h>
+#include <linux/of.h>
 
 #include <asm/prom.h>
 #include <asm/machdep.h>
 #include <asm/uaccess.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/mmu.h>
 
 /**
@@ -55,28 +55,6 @@ static struct device_node *derive_parent(const char *path)
         return parent;
 }
 
-static BLOCKING_NOTIFIER_HEAD(pSeries_reconfig_chain);
-
-int pSeries_reconfig_notifier_register(struct notifier_block *nb)
-{
-        return blocking_notifier_chain_register(&pSeries_reconfig_chain, nb);
-}
-EXPORT_SYMBOL_GPL(pSeries_reconfig_notifier_register);
-
-void pSeries_reconfig_notifier_unregister(struct notifier_block *nb)
-{
-        blocking_notifier_chain_unregister(&pSeries_reconfig_chain, nb);
-}
-EXPORT_SYMBOL_GPL(pSeries_reconfig_notifier_unregister);
-
-int pSeries_reconfig_notify(unsigned long action, void *p)
-{
-        int err = blocking_notifier_call_chain(&pSeries_reconfig_chain,
-                                                action, p);
-
-        return notifier_to_errno(err);
-}
-
 static int pSeries_reconfig_add_node(const char *path, struct property *proplist)
 {
         struct device_node *np;
@@ -100,13 +78,12 @@ static int pSeries_reconfig_add_node(const char *path, struct property *proplist
                 goto out_err;
         }
 
-        err = pSeries_reconfig_notify(PSERIES_RECONFIG_ADD, np);
+        err = of_attach_node(np);
         if (err) {
                 printk(KERN_ERR "Failed to add device node %s\n", path);
                 goto out_err;
         }
 
-        of_attach_node(np);
         of_node_put(np->parent);
 
         return 0;
@@ -134,9 +111,7 @@ static int pSeries_reconfig_remove_node(struct device_node *np)
                 return -EBUSY;
         }
 
-        pSeries_reconfig_notify(PSERIES_RECONFIG_REMOVE, np);
         of_detach_node(np);
-
         of_node_put(parent);
         of_node_put(np); /* Must decrement the refcount */
         return 0;
@@ -381,10 +356,9 @@ static int do_remove_property(char *buf, size_t bufsize)
 static int do_update_property(char *buf, size_t bufsize)
 {
         struct device_node *np;
-        struct pSeries_reconfig_prop_update upd_value;
         unsigned char *value;
         char *name, *end, *next_prop;
-        int rc, length;
+        int length;
         struct property *newprop;
         buf = parse_node(buf, bufsize, &np);
         end = buf + bufsize;
@@ -406,41 +380,7 @@ static int do_update_property(char *buf, size_t bufsize)
         if (!strcmp(name, "slb-size") || !strcmp(name, "ibm,slb-size"))
                 slb_set_size(*(int *)value);
 
-        upd_value.node = np;
-        upd_value.property = newprop;
-        pSeries_reconfig_notify(PSERIES_UPDATE_PROPERTY, &upd_value);
-
-        rc = prom_update_property(np, newprop);
-        if (rc)
-                return rc;
-
-        /* For memory under the ibm,dynamic-reconfiguration-memory node
-         * of the device tree, adding and removing memory is just an update
-         * to the ibm,dynamic-memory property instead of adding/removing a
-         * memory node in the device tree.  For these cases we still need to
-         * involve the notifier chain.
-         */
-        if (!strcmp(name, "ibm,dynamic-memory")) {
-                int action;
-
-                next_prop = parse_next_property(next_prop, end, &name,
-                                                &length, &value);
-                if (!next_prop)
-                        return -EINVAL;
-
-                if (!strcmp(name, "add"))
-                        action = PSERIES_DRCONF_MEM_ADD;
-                else
-                        action = PSERIES_DRCONF_MEM_REMOVE;
-
-                rc = pSeries_reconfig_notify(action, value);
-                if (rc) {
-                        prom_update_property(np, newprop);
-                        return rc;
-                }
-        }
-
-        return 0;
+        return prom_update_property(np, newprop);
 }
 
 /**
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index e3cb7ae61658..e1a5b8a32d25 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -40,6 +40,7 @@
 #include <linux/seq_file.h>
 #include <linux/root_dev.h>
 #include <linux/cpuidle.h>
+#include <linux/of.h>
 
 #include <asm/mmu.h>
 #include <asm/processor.h>
@@ -63,7 +64,6 @@
 #include <asm/smp.h>
 #include <asm/firmware.h>
 #include <asm/eeh.h>
-#include <asm/pSeries_reconfig.h>
 
 #include "plpar_wrappers.h"
 #include "pseries.h"
@@ -258,7 +258,7 @@ static int pci_dn_reconfig_notifier(struct notifier_block *nb, unsigned long act
         int err = NOTIFY_OK;
 
         switch (action) {
-        case PSERIES_RECONFIG_ADD:
+        case OF_RECONFIG_ATTACH_NODE:
                 pci = np->parent->data;
                 if (pci) {
                         update_dn_pci_info(np, pci->phb);
@@ -389,7 +389,7 @@ static void __init pSeries_setup_arch(void)
         /* Find and initialize PCI host bridges */
         init_pci_config_tokens();
         find_and_init_phbs();
-        pSeries_reconfig_notifier_register(&pci_dn_reconfig_nb);
+        of_reconfig_notifier_register(&pci_dn_reconfig_nb);
 
         pSeries_nvram_init();
 
diff --git a/drivers/crypto/nx/nx-842.c b/drivers/crypto/nx/nx-842.c
index 0ce625738677..6c4c000671c5 100644
--- a/drivers/crypto/nx/nx-842.c
+++ b/drivers/crypto/nx/nx-842.c
@@ -28,7 +28,6 @@
 #include <linux/slab.h>
 
 #include <asm/page.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/vio.h>
 
 #include "nx_csbcpb.h" /* struct nx_csbcpb */
@@ -1014,26 +1013,23 @@ error_out:
  *      NOTIFY_BAD encoded with error number on failure, use
  *              notifier_to_errno() to decode this value
  */
-static int nx842_OF_notifier(struct notifier_block *np,
-                                        unsigned long action,
-                                        void *update)
+static int nx842_OF_notifier(struct notifier_block *np, unsigned long action,
+                             void *update)
 {
-        struct pSeries_reconfig_prop_update *upd;
+        struct of_prop_reconfig *upd = update;
         struct nx842_devdata *local_devdata;
         struct device_node *node = NULL;
 
-        upd = (struct pSeries_reconfig_prop_update *)update;
-
         rcu_read_lock();
         local_devdata = rcu_dereference(devdata);
         if (local_devdata)
                 node = local_devdata->dev->of_node;
 
         if (local_devdata &&
-                        action == PSERIES_UPDATE_PROPERTY &&
-                        !strcmp(upd->node->name, node->name)) {
+                        action == OF_RECONFIG_UPDATE_PROPERTY &&
+                        !strcmp(upd->dn->name, node->name)) {
                 rcu_read_unlock();
-                nx842_OF_upd(upd->property);
+                nx842_OF_upd(upd->prop);
         } else
                 rcu_read_unlock();
 
@@ -1182,7 +1178,7 @@ static int __init nx842_probe(struct vio_dev *viodev,
         synchronize_rcu();
         kfree(old_devdata);
 
-        pSeries_reconfig_notifier_register(&nx842_of_nb);
+        of_reconfig_notifier_register(&nx842_of_nb);
 
         ret = nx842_OF_upd(NULL);
         if (ret && ret != -ENODEV) {
@@ -1228,7 +1224,7 @@ static int __exit nx842_remove(struct vio_dev *viodev)
         spin_lock_irqsave(&devdata_mutex, flags);
         old_devdata = rcu_dereference_check(devdata,
                         lockdep_is_held(&devdata_mutex));
-        pSeries_reconfig_notifier_unregister(&nx842_of_nb);
+        of_reconfig_notifier_unregister(&nx842_of_nb);
         rcu_assign_pointer(devdata, NULL);
         spin_unlock_irqrestore(&devdata_mutex, flags);
         synchronize_rcu();
diff --git a/drivers/crypto/nx/nx.c b/drivers/crypto/nx/nx.c
index 638110efae9b..f7a8a16aa7d3 100644
--- a/drivers/crypto/nx/nx.c
+++ b/drivers/crypto/nx/nx.c
@@ -33,7 +33,6 @@
 #include <linux/scatterlist.h>
 #include <linux/device.h>
 #include <linux/of.h>
-#include <asm/pSeries_reconfig.h>
 #include <asm/hvcall.h>
 #include <asm/vio.h>
 
diff --git a/drivers/of/base.c b/drivers/of/base.c
index bbd073f53c9f..87b63850e8dc 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1028,6 +1028,24 @@ int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
 }
 EXPORT_SYMBOL(of_parse_phandle_with_args);
 
+#if defined(CONFIG_OF_DYNAMIC)
+static int of_property_notify(int action, struct device_node *np,
+                              struct property *prop)
+{
+        struct of_prop_reconfig pr;
+
+        pr.dn = np;
+        pr.prop = prop;
+        return of_reconfig_notify(action, &pr);
+}
+#else
+static int of_property_notify(int action, struct device_node *np,
+                              struct property *prop)
+{
+        return 0;
+}
+#endif
+
 /**
  * prom_add_property - Add a property to a node
  */
@@ -1035,6 +1053,11 @@ int prom_add_property(struct device_node *np, struct property *prop)
 {
         struct property **next;
         unsigned long flags;
+        int rc;
+
+        rc = of_property_notify(OF_RECONFIG_ADD_PROPERTY, np, prop);
+        if (rc)
+                return rc;
 
         prop->next = NULL;
         write_lock_irqsave(&devtree_lock, flags);
@@ -1072,6 +1095,11 @@ int prom_remove_property(struct device_node *np, struct property *prop)
         struct property **next;
         unsigned long flags;
         int found = 0;
+        int rc;
+
+        rc = of_property_notify(OF_RECONFIG_REMOVE_PROPERTY, np, prop);
+        if (rc)
+                return rc;
 
         write_lock_irqsave(&devtree_lock, flags);
         next = &np->properties;
@@ -1114,7 +1142,11 @@ int prom_update_property(struct device_node *np,
 {
         struct property **next, *oldprop;
         unsigned long flags;
-        int found = 0;
+        int rc, found = 0;
+
+        rc = of_property_notify(OF_RECONFIG_UPDATE_PROPERTY, np, newprop);
+        if (rc)
+                return rc;
 
         if (!newprop->name)
                 return -EINVAL;
@@ -1160,6 +1192,26 @@ int prom_update_property(struct device_node *np,
  * device tree nodes.
  */
 
+static BLOCKING_NOTIFIER_HEAD(of_reconfig_chain);
+
+int of_reconfig_notifier_register(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_register(&of_reconfig_chain, nb);
+}
+
+int of_reconfig_notifier_unregister(struct notifier_block *nb)
+{
+        return blocking_notifier_chain_unregister(&of_reconfig_chain, nb);
+}
+
+int of_reconfig_notify(unsigned long action, void *p)
+{
+        int rc;
+
+        rc = blocking_notifier_call_chain(&of_reconfig_chain, action, p);
+        return notifier_to_errno(rc);
+}
+
 #ifdef CONFIG_PROC_DEVICETREE
 static void of_add_proc_dt_entry(struct device_node *dn)
 {
@@ -1179,9 +1231,14 @@ static void of_add_proc_dt_entry(struct device_node *dn)
 /**
  * of_attach_node - Plug a device node into the tree and global list.
  */
-void of_attach_node(struct device_node *np)
+int of_attach_node(struct device_node *np)
 {
         unsigned long flags;
+        int rc;
+
+        rc = of_reconfig_notify(OF_RECONFIG_ATTACH_NODE, np);
+        if (rc)
+                return rc;
 
         write_lock_irqsave(&devtree_lock, flags);
         np->sibling = np->parent->child;
@@ -1191,6 +1248,7 @@ void of_attach_node(struct device_node *np)
         write_unlock_irqrestore(&devtree_lock, flags);
 
         of_add_proc_dt_entry(np);
+        return 0;
 }
 
 #ifdef CONFIG_PROC_DEVICETREE
@@ -1220,23 +1278,28 @@ static void of_remove_proc_dt_entry(struct device_node *dn)
  * The caller must hold a reference to the node.  The memory associated with
  * the node is not freed until its refcount goes to zero.
  */
-void of_detach_node(struct device_node *np)
+int of_detach_node(struct device_node *np)
 {
         struct device_node *parent;
         unsigned long flags;
+        int rc = 0;
+
+        rc = of_reconfig_notify(OF_RECONFIG_DETACH_NODE, np);
+        if (rc)
+                return rc;
 
         write_lock_irqsave(&devtree_lock, flags);
 
         if (of_node_check_flag(np, OF_DETACHED)) {
                 /* someone already detached it */
                 write_unlock_irqrestore(&devtree_lock, flags);
-                return;
+                return rc;
         }
 
         parent = np->parent;
         if (!parent) {
                 write_unlock_irqrestore(&devtree_lock, flags);
-                return;
+                return rc;
         }
 
         if (allnodes == np)
@@ -1265,6 +1328,7 @@ void of_detach_node(struct device_node *np)
         write_unlock_irqrestore(&devtree_lock, flags);
 
         of_remove_proc_dt_entry(np);
+        return rc;
 }
 #endif /* defined(CONFIG_OF_DYNAMIC) */
 
diff --git a/include/linux/of.h b/include/linux/of.h
index 72843b72a2b2..fb5d87b66e3e 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -22,6 +22,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/spinlock.h>
 #include <linux/topology.h>
+#include <linux/notifier.h>
 
 #include <asm/byteorder.h>
 #include <asm/errno.h>
@@ -272,11 +273,24 @@ extern int prom_remove_property(struct device_node *np, struct property *prop);
 extern int prom_update_property(struct device_node *np,
                                 struct property *newprop);
 
-#if defined(CONFIG_OF_DYNAMIC)
 /* For updating the device tree at runtime */
-extern void of_attach_node(struct device_node *);
-extern void of_detach_node(struct device_node *);
-#endif
+#define OF_RECONFIG_ATTACH_NODE         0x0001
+#define OF_RECONFIG_DETACH_NODE         0x0002
+#define OF_RECONFIG_ADD_PROPERTY        0x0003
+#define OF_RECONFIG_REMOVE_PROPERTY     0x0004
+#define OF_RECONFIG_UPDATE_PROPERTY     0x0005
+
+struct of_prop_reconfig {
+        struct device_node      *dn;
+        struct property         *prop;
+};
+
+extern int of_reconfig_notifier_register(struct notifier_block *);
+extern int of_reconfig_notifier_unregister(struct notifier_block *);
+extern int of_reconfig_notify(unsigned long, void *);
+
+extern int of_attach_node(struct device_node *);
+extern int of_detach_node(struct device_node *);
 
 #define of_match_ptr(_ptr)      (_ptr)