[U-Boot] [PATCH v2] net: make net_random_ethaddr() more random

Michael Walle michael at walle.cc
Tue Aug 27 08:13:52 UTC 2019

The net_random_ethaddr() tries to get some entropy from different
startup times of a board. The seed is initialized with get_timer() which
has only a granularity of milliseconds. We can do better if we use
get_ticks() which returns the raw timer ticks. Using this we have a
higher chance of getting different values at startup.

Signed-off-by: Michael Walle <michael at walle.cc>
since v1:
 - Removed the and-mask. Since there were no more comments I did some tests
   and apparently there are no compiler warnings.

 include/net.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net.h b/include/net.h
index a54d5eeac5..75a16e4c8f 100644
--- a/include/net.h
+++ b/include/net.h
@@ -816,7 +816,7 @@ static inline int is_valid_ethaddr(const u8 *addr)
 static inline void net_random_ethaddr(uchar *addr)
 	int i;
-	unsigned int seed = get_timer(0);
+	unsigned int seed = get_ticks();
 	for (i = 0; i < 6; i++)
 		addr[i] = rand_r(&seed);

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