of_find_node_by_phandle() takes a lot of time finding
right node when your intended device is too right-side
in the fdt. Reason is, we search each device serially
from the fdt, starting from left-most to right-most.
Implement, device-phandle relation in hash-table so
that look up can be faster.
Change-Id: I4a2bc7eff6de142e4f91a7bf474893a45e61c128
Signed-off-by: Chintan Pandya <cpandya@xxxxxxxxxxxxxx>
---
drivers/of/base.c | 9 +++++++--
drivers/of/fdt.c | 18 ++++++++++++++++++
include/linux/of.h | 6 ++++++
3 files changed, 31 insertions(+), 2 deletions(-)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index a0bccb5..3e06316 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -25,6 +25,7 @@
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/hashtable.h>
#include <linux/of_graph.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
@@ -1099,10 +1100,14 @@ struct device_node *of_find_node_by_phandle(phandle handle)
if (!handle)
return NULL;
- raw_spin_lock_irqsave(&devtree_lock, flags);
- for_each_of_allnodes(np)
+ spin_lock(&dt_hash_spinlock);
+ hash_for_each_possible(dt_hash_table, np, hash, handle)
if (np->phandle == handle)
break;
+
+ spin_unlock(&dt_hash_spinlock);
+
+ raw_spin_lock_irqsave(&devtree_lock, flags);
of_node_get(np);
raw_spin_unlock_irqrestore(&devtree_lock, flags);
return np;
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index c0914fb..f0e78a7 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -31,6 +31,10 @@
#include <asm/setup.h> /* for COMMAND_LINE_SIZE */
#include <asm/page.h>
+static bool dt_hash_needs_init = true;
+DECLARE_HASHTABLE(dt_hash_table, DT_HASH_BITS);
+DEFINE_SPINLOCK(dt_hash_spinlock);
+
/*
* of_fdt_limit_memory - limit the number of regions in the /memory node
* @limit: maximum entries
@@ -227,6 +231,20 @@ static void populate_properties(const void *blob,
pprev = &pp->next;
}
+ /*
+ * In 'dryrun = true' cases, np is some non-NULL junk. So, protect
+ * against those cases.
+ */
+ if (!dryrun && np->phandle) {
+ spin_lock(&dt_hash_spinlock);
+ if (dt_hash_needs_init) {
+ dt_hash_needs_init = false;
+ hash_init(dt_hash_table);
+ }
+ hash_add(dt_hash_table, &np->hash, np->phandle);
+ spin_unlock(&dt_hash_spinlock);
+ }
+
/* With version 0x10 we may not have the name property,
* recreate it here from the unit name if absent
*/
diff --git a/include/linux/of.h b/include/linux/of.h
index 299aeb1..5b3f4f1 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -25,6 +25,7 @@
#include <linux/notifier.h>
#include <linux/property.h>
#include <linux/list.h>
+#include <linux/hashtable.h>
#include <asm/byteorder.h>
#include <asm/errno.h>
@@ -61,6 +62,7 @@ struct device_node {
struct kobject kobj;
unsigned long _flags;
void *data;
+ struct hlist_node hash;
#if defined(CONFIG_SPARC)
const char *path_component_name;
unsigned int unique_id;
@@ -68,6 +70,10 @@ struct device_node {
#endif
};
+#define DT_HASH_BITS 6
+extern DECLARE_HASHTABLE(dt_hash_table, DT_HASH_BITS);
+extern spinlock_t dt_hash_spinlock;
+
#define MAX_PHANDLE_ARGS 16
struct of_phandle_args {
struct device_node *np;
--
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