target/linux/brcm2708/patches-4.9/950-0027-bcm2835-rng-Avoid-initialising-if-already-enabled.patch

   1 From ecba31015228961644ad8e17bcf132eea9c7a7f3 Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Tue, 6 Dec 2016 17:05:39 +0000
   4 Subject: [PATCH] bcm2835-rng: Avoid initialising if already enabled
   5
   6 Avoids the 0x40000 cycles of warmup again if firmware has already used it
   7 ---
   8  drivers/char/hw_random/bcm2835-rng.c | 7 ++++---
   9  1 file changed, 4 insertions(+), 3 deletions(-)
  10
  11 --- a/drivers/char/hw_random/bcm2835-rng.c
  12 +++ b/drivers/char/hw_random/bcm2835-rng.c
  13 @@ -102,9 +102,10 @@ static int bcm2835_rng_probe(struct plat
  14                 rng_setup(rng_base);
  15
  16         /* set warm-up count & enable */
  17 -       __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
  18 -       __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
  19 -
  20 +       if (!(__raw_readl(rng_base + RNG_CTRL) & RNG_RBGEN)) {
  21 +               __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
  22 +               __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
  23 +       }
  24         /* register driver */
  25         err = hwrng_register(&bcm2835_rng_ops);
  26         if (err) {