| Message ID | 20210304073308.25906-3-noltari@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | hwrng: bcm2835: add reset support | expand |
On Thu, 2021-03-04 at 08:33 +0100, Álvaro Fernández Rojas wrote: > BCM6368 devices need to reset the in order to generate true random numbers. > This is what BCM6368 produces without a reset: > root@OpenWrt:/# 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@gmail.com> > --- > v5: remove reset_control_rearm(). Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> regards Philipp
diff --git a/drivers/char/hw_random/bcm2835-rng.c b/drivers/char/hw_random/bcm2835-rng.c index be5be395b341..e7dd457e9b22 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) @@ -92,6 +94,10 @@ static int bcm2835_rng_init(struct hwrng *rng) if (ret) 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); @@ -156,6 +162,10 @@ static int bcm2835_rng_probe(struct platform_device *pdev) if (IS_ERR(priv->clk)) return PTR_ERR(priv->clk); + 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;
BCM6368 devices need to reset the in order to generate true random numbers. This is what BCM6368 produces without a reset: root@OpenWrt:/# 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@gmail.com> --- v5: remove reset_control_rearm(). v4: add reset_control_rearm(). v3: no changes. v2: no changes. drivers/char/hw_random/bcm2835-rng.c | 10 ++++++++++ 1 file changed, 10 insertions(+)