From: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
To: Martin Kaiser <martin@kaiser.cx>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
NXP Linux Team <linux-imx@nxp.com>,
"open list:HARDWARE RANDOM NUMBER GENERATOR CORE"
<linux-crypto@vger.kernel.org>,
linux-arm-kernel@lists.infradead.org,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/6] hwrng: imx-rngc - use automatic seeding
Date: Wed, 12 Feb 2020 21:54:51 +0530 [thread overview]
Message-ID: <CANc+2y60cCtDwBi1jaV=eMtTwoihRf2WiKW7Zo3iC9ALv2OVSw@mail.gmail.com> (raw)
In-Reply-To: <20200128110102.11522-3-martin@kaiser.cx>
On Tue, 28 Jan 2020 at 16:31, Martin Kaiser <martin@kaiser.cx> wrote:
>
> The rngc requires a new seed for its prng after generating 2^20 160-bit
> words of random data. At the moment, we seed the prng only once during
> initalisation.
>
> Set the rngc to auto seed mode so that it kicks off the internal
> reseeding operation when a new seed is required.
>
> Keep the manual calculation of the initial seed when the device is
> probed and switch to automatic seeding afterwards.
>
> Signed-off-by: Martin Kaiser <martin@kaiser.cx>
> ---
> drivers/char/hw_random/imx-rngc.c | 16 ++++++++++++++--
> 1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/hw_random/imx-rngc.c b/drivers/char/hw_random/imx-rngc.c
> index 0576801944fd..903894518c8d 100644
> --- a/drivers/char/hw_random/imx-rngc.c
> +++ b/drivers/char/hw_random/imx-rngc.c
> @@ -31,6 +31,7 @@
>
> #define RNGC_CTRL_MASK_ERROR 0x00000040
> #define RNGC_CTRL_MASK_DONE 0x00000020
> +#define RNGC_CTRL_AUTO_SEED 0x00000010
>
> #define RNGC_STATUS_ERROR 0x00010000
> #define RNGC_STATUS_FIFO_LEVEL_MASK 0x00000f00
> @@ -167,7 +168,7 @@ static irqreturn_t imx_rngc_irq(int irq, void *priv)
> static int imx_rngc_init(struct hwrng *rng)
> {
> struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng);
> - u32 cmd;
> + u32 cmd, ctrl;
> int ret;
>
> /* clear error */
> @@ -192,7 +193,18 @@ static int imx_rngc_init(struct hwrng *rng)
>
> } while (rngc->err_reg == RNGC_ERROR_STATUS_STAT_ERR);
>
> - return rngc->err_reg ? -EIO : 0;
> + if (rngc->err_reg)
> + return -EIO;
> +
> + /*
> + * enable automatic seeding, the rngc creates a new seed automatically
> + * after serving 2^20 random 160-bit words
> + */
> + ctrl = readl(rngc->base + RNGC_CONTROL);
> + ctrl |= RNGC_CTRL_AUTO_SEED;
> + writel(ctrl, rngc->base + RNGC_CONTROL);
> +
> + return 0;
> }
>
> static int imx_rngc_probe(struct platform_device *pdev)
> --
> 2.20.1
>
Reviewed-by: PrasannaKumar Muralidharan <prasannatsmkumar@gmail.com>
next prev parent reply other threads:[~2020-02-12 16:25 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 11:00 [PATCH 0/6] imx-rngc - several small fixes Martin Kaiser
2020-01-28 11:00 ` [PATCH 1/6] hwrng: imx-rngc - fix an error path Martin Kaiser
2020-02-12 16:22 ` PrasannaKumar Muralidharan
2020-01-28 11:00 ` [PATCH 2/6] hwrng: imx-rngc - use automatic seeding Martin Kaiser
2020-02-12 16:24 ` PrasannaKumar Muralidharan [this message]
2020-01-28 11:00 ` [PATCH 3/6] hwrng: imx-rngc - use devres for registration Martin Kaiser
2020-02-12 16:13 ` PrasannaKumar Muralidharan
2020-02-17 9:35 ` Martin Kaiser
2020-01-28 11:01 ` [PATCH 4/6] hwrng: imx-rngc - (trivial) simplify error prints Martin Kaiser
2020-02-12 16:24 ` PrasannaKumar Muralidharan
2020-01-28 11:01 ` [PATCH 5/6] hwrng: imx-rngc - check the rng type Martin Kaiser
2020-02-12 16:23 ` PrasannaKumar Muralidharan
2020-01-28 11:01 ` [PATCH 6/6] hwrng: imx-rngc - simplify interrupt mask/unmask Martin Kaiser
2020-03-05 20:58 ` [PATCH v2 0/5] imx-rngc - several small fixes Martin Kaiser
2020-03-05 20:58 ` [PATCH v2 1/5] hwrng: imx-rngc - fix an error path Martin Kaiser
2020-03-05 20:58 ` [PATCH v2 2/5] hwrng: imx-rngc - use automatic seeding Martin Kaiser
2020-03-05 20:58 ` [PATCH v2 3/5] hwrng: imx-rngc - (trivial) simplify error prints Martin Kaiser
2020-03-05 20:58 ` [PATCH v2 4/5] hwrng: imx-rngc - check the rng type Martin Kaiser
2020-03-05 20:58 ` [PATCH v2 5/5] hwrng: imx-rngc - simplify interrupt mask/unmask Martin Kaiser
2020-03-12 12:39 ` [PATCH v2 0/5] imx-rngc - several small fixes Herbert Xu
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