powerpc/pseries: Add pseries update notifier for OFDT prop changes

This adds an update notifier mechanism for changes to properties in the
device tree.  One use of this would be a device driver that needs to act
on changes to it's properties in the device tree after a live migration
or a dynamic activation that is triggered by updates to ofdt properties.

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Kent Yoder <key@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 19 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/pSeries_reconfig.h b/arch/powerpc/include/asm/pSeries_reconfig.h
index 23cd6cc30bcf..c07edfe98b98 100644
--- a/arch/powerpc/include/asm/pSeries_reconfig.h
+++ b/arch/powerpc/include/asm/pSeries_reconfig.h
@@ -13,6 +13,18 @@
 #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 *);
diff --git a/arch/powerpc/platforms/pseries/reconfig.c b/arch/powerpc/platforms/pseries/reconfig.c
index 168651acdd83..7b3bf76ef834 100644
--- a/arch/powerpc/platforms/pseries/reconfig.c
+++ b/arch/powerpc/platforms/pseries/reconfig.c
@@ -103,11 +103,13 @@ 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)
 {
@@ -426,6 +428,7 @@ 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;
@@ -454,6 +457,10 @@ static int do_update_property(char *buf, size_t bufsize)
                 return -ENODEV;
         }
 
+        upd_value.node = np;
+        upd_value.property = newprop;
+        pSeries_reconfig_notify(PSERIES_UPDATE_PROPERTY, &upd_value);
+
         rc = prom_update_property(np, newprop, oldprop);
         if (rc)
                 return rc;