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Message-Id: <20210223170006.29558-3-noltari@gmail.com>
Date: Tue, 23 Feb 2021 18:00:06 +0100
From: Álvaro Fernández Rojas
<noltari@...il.com>
To: Matt Mackall <mpm@...enic.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Rob Herring <robh+dt@...nel.org>,
Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
Florian Fainelli <f.fainelli@...il.com>,
Ray Jui <rjui@...adcom.com>,
Scott Branden <sbranden@...adcom.com>,
bcm-kernel-feedback-list@...adcom.com,
Philipp Zabel <p.zabel@...gutronix.de>,
Mark Brown <broonie@...nel.org>,
Álvaro Fernández Rojas
<noltari@...il.com>, Guenter Roeck <linux@...ck-us.net>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Nícolas F. R. A. Prado
<nfraprado@...tonmail.com>,
Rikard Falkeborn <rikard.falkeborn@...il.com>,
Stefan Wahren <stefan.wahren@...e.com>,
linux-crypto@...r.kernel.org, devicetree@...r.kernel.org,
linux-rpi-kernel@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 2/2] hwrng: bcm2835: add reset support
BCM6368 devices need to reset the in order to generate true random numbers.
This is what BCM6368 produces without a reset:
root@...nWrt:/# cat /dev/hwrng | rngtest -c 1000
rngtest 6.10
Copyright (c) 2004 by Henrique de Moraes Holschuh
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
rngtest: starting FIPS tests...
rngtest: bits received from input: 20000032
rngtest: FIPS 140-2 successes: 0
rngtest: FIPS 140-2 failures: 1000
rngtest: FIPS 140-2(2001-10-10) Monobit: 2
rngtest: FIPS 140-2(2001-10-10) Poker: 1000
rngtest: FIPS 140-2(2001-10-10) Runs: 1000
rngtest: FIPS 140-2(2001-10-10) Long run: 30
rngtest: FIPS 140-2(2001-10-10) Continuous run: 0
rngtest: input channel speed: (min=37.253; avg=320.827; max=635.783)Mibits/s
rngtest: FIPS tests speed: (min=12.141; avg=15.034; max=16.428)Mibits/s
rngtest: Program run time: 1336176 microseconds
cat: write error: Broken pipe
Signed-off-by: Álvaro Fernández Rojas <noltari@...il.com>
---
v3: no changes.
v2: no changes.
drivers/char/hw_random/bcm2835-rng.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c
index 1a7c43b43c6b..1b93a896d8e8 100644
--- a/drivers/char/hw_random/bcm2835-rng.c
+++ b/drivers/char/hw_random/bcm2835-rng.c
@@ -13,6 +13,7 @@
#include <linux/platform_device.h>
#include <linux/printk.h>
#include <linux/clk.h>
+#include <linux/reset.h>
#define RNG_CTRL 0x0
#define RNG_STATUS 0x4
@@ -32,6 +33,7 @@ struct bcm2835_rng_priv {
void __iomem *base;
bool mask_interrupts;
struct clk *clk;
+ struct reset_control *reset;
};
static inline struct bcm2835_rng_priv *to_rng_priv(struct hwrng *rng)
@@ -94,6 +96,10 @@ static int bcm2835_rng_init(struct hwrng *rng)
return ret;
}
+ ret = reset_control_reset(priv->reset);
+ if (ret)
+ return ret;
+
if (priv->mask_interrupts) {
/* mask the interrupt */
val = rng_readl(priv, RNG_INT_MASK);
@@ -159,6 +165,10 @@ static int bcm2835_rng_probe(struct platform_device *pdev)
if (PTR_ERR(priv->clk) == -EPROBE_DEFER)
return -EPROBE_DEFER;
+ priv->reset = devm_reset_control_get_optional_exclusive(dev, NULL);
+ if (IS_ERR(priv->reset))
+ return PTR_ERR(priv->reset);
+
priv->rng.name = pdev->name;
priv->rng.init = bcm2835_rng_init;
priv->rng.read = bcm2835_rng_read;
--
2.20.1
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