--- /dev/null
+From ad841f8241807114d61572c1ca1636e7a43e6d93 Mon Sep 17 00:00:00 2001
+From: popcornmix <popcornmix@gmail.com>
+Date: Tue, 6 Dec 2016 17:05:39 +0000
+Subject: [PATCH] bcm2835-rng: Avoid initialising if already enabled
+
+Avoids the 0x40000 cycles of warmup again if firmware has already used it
+---
+ drivers/char/hw_random/bcm2835-rng.c | 7 ++++---
+ 1 file changed, 4 insertions(+), 3 deletions(-)
+
+--- a/drivers/char/hw_random/bcm2835-rng.c
++++ b/drivers/char/hw_random/bcm2835-rng.c
+@@ -62,9 +62,10 @@ static int bcm2835_rng_probe(struct plat
+ bcm2835_rng_ops.priv = (unsigned long)rng_base;
+
+ /* set warm-up count & enable */
+- __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
+- __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
+-
++ if (!(__raw_readl(rng_base + RNG_CTRL) & RNG_RBGEN)) {
++ __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
++ __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
++ }
+ /* register driver */
+ err = hwrng_register(&bcm2835_rng_ops);
+ if (err) {