From b7791eea502e0d98ae204750aff2abafc431fb11 Mon Sep 17 00:00:00 2001 From: popcornmix 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) {