From 6e933cd69ad9eadcc26d6db01b066e524b8894c2 Mon Sep 17 00:00:00 2001 From: Sam Day Date: Wed, 12 Feb 2025 07:01:39 +0000 Subject: [PATCH] rng: msm: don't enable PRNG if it's already enabled msm_rng_enable is supposed to skip writing to LFSR_CFG + CONFIG registers in the PRNG_ block if PRNG_CONFIG_HW_ENABLE is already set. The logic to test for this was inverted. Without this fix, the driver was causing SError aborts on my MSM8916 device. Stephan Gerhold suggested this was probably because TZ has marked this as a protected register, since it would also be using it for RNG. Fixes: 033ec636fcb ("rng: Add Qualcomm MSM PRNG driver") Suggested-by: Stephan Gerhold Reviewed-by: Neil Armstrong Signed-off-by: Sam Day Reviewed-by: Caleb Connolly Link: https://lore.kernel.org/r/20250212-msm-rng-fixes-v2-3-645cf8d3fd3c@samcday.com Signed-off-by: Caleb Connolly --- drivers/rng/msm_rng.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/rng/msm_rng.c b/drivers/rng/msm_rng.c index f790d3b60f9..01505509103 100644 --- a/drivers/rng/msm_rng.c +++ b/drivers/rng/msm_rng.c @@ -76,7 +76,7 @@ static int msm_rng_enable(struct msm_rng_priv *priv, int enable) if (enable) { /* Enable PRNG only if it is not already enabled */ val = readl_relaxed(priv->base + PRNG_CONFIG); - if (val & PRNG_CONFIG_HW_ENABLE) { + if (!(val & PRNG_CONFIG_HW_ENABLE)) { val = readl_relaxed(priv->base + PRNG_LFSR_CFG); val &= ~PRNG_LFSR_CFG_MASK; val |= PRNG_LFSR_CFG_CLOCKS; -- 2.39.5