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[v6,0/3] hwrng: bcm2835: add reset support

Message ID 20210305070132.2986-1-noltari@gmail.com
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Series hwrng: bcm2835: add reset support | expand

Message

Álvaro Fernández Rojas March 5, 2021, 7:01 a.m. UTC 
Some devices may need to perform a reset before using the RNG, such as the
BCM6368.

v6: fix dt-bindings documentation, add patch makings clocks mandatory for
 BCM6368.
v5: remove reset_control_rearm() and apply on latest herbert/cryptodev-2.6.git.
v4: fix documentation, add reset_control_rearm().
v3: make resets required if brcm,bcm6368-rng.
v2: document reset support.

Álvaro Fernández Rojas (3):
  dt-bindings: rng: bcm2835: add clock constraints
  dt-bindings: rng: bcm2835: document reset support
  hwrng: bcm2835: add reset support

 .../devicetree/bindings/rng/brcm,bcm2835.yaml | 21 +++++++++++++++++++
 drivers/char/hw_random/bcm2835-rng.c          | 10 +++++++++
 2 files changed, 31 insertions(+)

Comments

Philipp Zabel March 5, 2021, 8:07 a.m. UTC | #1 
On Fri, 2021-03-05 at 08:01 +0100, Álvaro Fernández Rojas wrote:
> BCM6368 devices need to reset the IPSEC controller 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
> 
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

> ---
>  v6: fix commit description.
>  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(+)
> 
> 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;
Rob Herring (Arm) March 8, 2021, 9:52 p.m. UTC | #2 
On Fri, 05 Mar 2021 08:01:30 +0100, Álvaro Fernández Rojas wrote:
> brcm,bcm6368-rng controllers require enabling the IPSEC clock in order to get

> a functional RNG.

> 

> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

> ---

>  v6: add new patch making clocks mandatory for BCM6368.

> 

>  .../devicetree/bindings/rng/brcm,bcm2835.yaml          | 10 ++++++++++

>  1 file changed, 10 insertions(+)

> 


Reviewed-by: Rob Herring <robh@kernel.org>
Florian Fainelli March 8, 2021, 10 p.m. UTC | #3 
On 3/4/21 11:01 PM, Álvaro Fernández Rojas wrote:
> BCM6368 devices need to reset the IPSEC controller 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

> 

> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>


Acked-by: Florian Fainelli <f.fainelli@gmail.com>

-- 
Florian