[PATCH 08/10] hwrng: stm32 - support RNG configuration locking mechanism

Gatien Chevallier
2023-09-08T16:54:47Z

If "st,rng-lock-conf" DT binding property is set for a stm32-rng node,
the RNG configuration will be locked until next hardware block reset
or platform reset.

Signed-off-by: Gatien Chevallier <gatien.chevallier@foss.st.com>
---
drivers/char/hw_random/stm32-rng.c | 5 +++++
1 file changed, 5 insertions(+)

diff --git a/drivers/char/hw_random/stm32-rng.c b/drivers/char/hw_random/stm32-rng.c
index 3b77f1fe6aea..0243b889ac54 100644
--- a/drivers/char/hw_random/stm32-rng.c
+++ b/drivers/char/hw_random/stm32-rng.c
@@ -62,6 +62,7 @@ struct stm32_rng_private {
struct reset_control *rst;
const struct stm32_rng_data *data;
bool ced;
+ bool lock_conf;
};

/*
@@ -301,6 +302,9 @@ static int stm32_rng_init(struct hwrng *rng)

reg &= ~RNG_CR_CONDRST;
reg |= RNG_CR_RNGEN;
+ if (priv->lock_conf)
+ reg |= RNG_CR_CONFLOCK;
+
writel_relaxed(reg, priv->base + RNG_CR);

err = readl_relaxed_poll_timeout_atomic(priv->base + RNG_CR, reg,
@@ -439,6 +443,7 @@ static int stm32_rng_probe(struct platform_device *ofdev)
}

priv->ced = of_property_read_bool(np, "clock-error-detect");
+ priv->lock_conf = of_property_read_bool(np, "st,rng-lock-conf");

priv->data = of_device_get_match_data(dev);
if (!priv->data)
--
2.25.1