target/linux/bcm27xx/patches-4.19/950-0020-bcm2835-rng-Avoid-initialising-if-already-enabled.patch

   1 From d5df60f32f3c3b2f7f6d758ac08de6acb9fd947f 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 | 6 ++++--
   9  1 file changed, 4 insertions(+), 2 deletions(-)
  10
  11 --- a/drivers/char/hw_random/bcm2835-rng.c
  12 +++ b/drivers/char/hw_random/bcm2835-rng.c
  13 @@ -105,8 +105,10 @@ static int bcm2835_rng_init(struct hwrng
  14         }
  15
  16         /* set warm-up count & enable */
  17 -       rng_writel(priv, RNG_WARMUP_COUNT, RNG_STATUS);
  18 -       rng_writel(priv, RNG_RBGEN, RNG_CTRL);
  19 +       if (!(rng_readl(priv, RNG_CTRL) & RNG_RBGEN)) {
  20 +               rng_writel(priv, RNG_WARMUP_COUNT, RNG_STATUS);
  21 +               rng_writel(priv, RNG_RBGEN, RNG_CTRL);
  22 +       }
  23
  24         return ret;
  25  }