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
6 Avoids the 0x40000 cycles of warmup again if firmware has already used it
8 drivers/char/hw_random/bcm2835-rng.c | 7 ++++---
9 1 file changed, 4 insertions(+), 3 deletions(-)
11 --- a/drivers/char/hw_random/bcm2835-rng.c
12 +++ b/drivers/char/hw_random/bcm2835-rng.c
13 @@ -62,9 +62,10 @@ static int bcm2835_rng_probe(struct plat
14 bcm2835_rng_ops.priv = (unsigned long)rng_base;
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);
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);
25 err = hwrng_register(&bcm2835_rng_ops);