target/linux/brcm2708/patches-4.4/0561-bcm2835-rng-Avoid-initialising-if-already-enabled.patch

   1 From b7791eea502e0d98ae204750aff2abafc431fb11 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 diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
  12 index 7192ec2..2ff49c1 100644
  13 --- a/drivers/char/hw_random/bcm2835-rng.c
  14 +++ b/drivers/char/hw_random/bcm2835-rng.c
  15 @@ -62,9 +62,10 @@ static int bcm2835_rng_probe(struct platform_device *pdev)
  16         bcm2835_rng_ops.priv = (unsigned long)rng_base;
  17
  18         /* set warm-up count & enable */
  19 -       __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
  20 -       __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
  21 -
  22 +       if (!(__raw_readl(rng_base + RNG_CTRL) & RNG_RBGEN)) {
  23 +               __raw_writel(RNG_WARMUP_COUNT, rng_base + RNG_STATUS);
  24 +               __raw_writel(RNG_RBGEN, rng_base + RNG_CTRL);
  25 +       }
  26         /* register driver */
  27         err = hwrng_register(&bcm2835_rng_ops);
  28         if (err) {
  29 --
  30 2.1.4
  31