RE: [PATCH] crypto: caam - adjust RNG timing to support more devices

[Meenakshi Aggarwal]

Hi Bastian,

We have tested the patch on i.mx8mm board and we did not face any issue with the patch.

Please share your imx8mm board revision and complete logs (including bootloader logs),
It will help in investigating the issue you are facing.

Thanks,
Meenakshi

> -----Original Message-----
> From: Bastian Krause <bst@xxxxxxxxxxxxxx>
> Sent: Tuesday, July 18, 2023 3:13 PM
> To: Meenakshi Aggarwal <meenakshi.aggarwal@xxxxxxx>; Horia Geanta
> <horia.geanta@xxxxxxx>; Varun Sethi <V.Sethi@xxxxxxx>; Pankaj Gupta
> <pankaj.gupta@xxxxxxx>; Gaurav Jain <gaurav.jain@xxxxxxx>;
> herbert@xxxxxxxxxxxxxxxxxxx; davem@xxxxxxxxxxxxx; linux-
> crypto@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Victoria Milhoan <vicki.milhoan@xxxxxxxxxxxxx>; Dan Douglass
> <dan.douglass@xxxxxxx>; Vipul Kumar <vipul_kumar@xxxxxxxxxx>;
> kernel@xxxxxxxxxxxxxx
> Subject: Re: [PATCH] crypto: caam - adjust RNG timing to support more devices
>
> On 7/17/23 14:43, Bastian Krause wrote:
> > On 6/12/23 10:26, meenakshi.aggarwal@xxxxxxx wrote:
> >> From: Victoria Milhoan <vicki.milhoan@xxxxxxxxxxxxx>
> >>
> >> Adjust RNG timing parameters to support more i.MX6 devices.
> >>
> >> Signed-off-by: Victoria Milhoan <vicki.milhoan@xxxxxxxxxxxxx>
> >> Signed-off-by: Dan Douglass <dan.douglass@xxxxxxx>
> >> Signed-off-by: Vipul Kumar <vipul_kumar@xxxxxxxxxx>
> >> Signed-off-by: Horia Geantă <horia.geanta@xxxxxxx>
> >> ---
> >>   drivers/crypto/caam/ctrl.c | 4 ++--
> >>   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > This patch seems to breaks CAAM RNG instantiation on an i.MX8MM at my end:
> >
> > caam 30900000.crypto: Entropy delay = 3200 caam 30900000.crypto:
> > Entropy delay = 3600 [...] caam 30900000.crypto: Entropy delay = 12400
> > caam 30900000.crypto: failed to instantiate RNG
> > caam: probe of 30900000.crypto failed with error -11
> >
> > If I revert this patch or increase RTSDCTL_ENT_DLY_MAX to a value >
> > 66800, it works again:
> >
> > caam 30900000.crypto: Entropy delay = 32800 caam 30900000.crypto:
> > Entropy delay = 33200 [...] caam 30900000.crypto: Entropy delay =
> > 66800 caam 30900000.crypto: Instantiated RNG4 SH0 caam
> > 30900000.crypto: Instantiated RNG4 SH1 caam 30900000.crypto: device ID
> > = 0x0a16040100000000 (Era 9) caam 30900000.crypto: job rings = 2, qi =
> > 0 caam algorithms registered in /proc/crypto caam 30900000.crypto:
> > caam pkc algorithms registered in /proc/crypto caam 30900000.crypto:
> > registering rng-caam Executing RNG SELF-TEST with wait
> > random: crng init done
> > caam 30900000.crypto: rng crypto API alg registered prng-caam
>
> This ^ was the kernel log for..
>
>
> --- a/drivers/crypto/caam/regs.h
> +++ b/drivers/crypto/caam/regs.h
> @@@ -522,7 -522,7 +522,7 @@@ struct rng4tst
>    #define RTSDCTL_ENT_DLY_SHIFT 16
>    #define RTSDCTL_ENT_DLY_MASK (0xffff << RTSDCTL_ENT_DLY_SHIFT)
>    #define RTSDCTL_ENT_DLY_MIN 3200
> --#define RTSDCTL_ENT_DLY_MAX 12800
> ++#define RTSDCTL_ENT_DLY_MAX 70000
>    #define RTSDCTL_SAMP_SIZE_MASK 0xffff
>    #define RTSDCTL_SAMP_SIZE_VAL 512
>          u32 rtsdctl;            /* seed control register */
>
>
> For completion's sake: Reverting this patch..
>
>
> --- a/drivers/crypto/caam/ctrl.c
> +++ b/drivers/crypto/caam/ctrl.c
> @@ -383,7 +383,7 @@ static void kick_trng(struct device *dev, int ent_delay)
>                  /* min. freq. count, equal to 1/4 of the entropy sample length */
>                  wr_reg32(&r4tst->rtfrqmin, val >> 2);
>                  /* max. freq. count, equal to 16 times the entropy sample length */
> -               wr_reg32(&r4tst->rtfrqmax, val << 4);
> +               wr_reg32(&r4tst->rtfrqmax, RTFRQMAX_DISABLE);
>          }
>
>          wr_reg32(&r4tst->rtsdctl, (val << RTSDCTL_ENT_DLY_SHIFT) |
>
>
> ..produces this kernel log (without RNG SELF-TEST):
>
> caam 30900000.crypto: Entropy delay = 3200 caam 30900000.crypto: Entropy
> delay = 3600 caam 30900000.crypto: Instantiated RNG4 SH0 caam
> 30900000.crypto: Instantiated RNG4 SH1 caam 30900000.crypto: device ID =
> 0x0a16040100000000 (Era 9) caam 30900000.crypto: job rings = 2, qi = 0 caam
> algorithms registered in /proc/crypto caam 30900000.crypto: caam pkc
> algorithms registered in /proc/crypto caam 30900000.crypto: registering rng-
> caam caam 30900000.crypto: rng crypto API alg registered prng-caam
> random: crng init done
>
> Regards,
> Bastian
>
> >>
> >> diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
> >> index 5fed3cf354c0..62dd069942e4 100644
> >> --- a/drivers/crypto/caam/ctrl.c
> >> +++ b/drivers/crypto/caam/ctrl.c
> >> @@ -383,8 +383,8 @@ static void kick_trng(struct device *dev, int
> >> ent_delay)
> >>       wr_reg32(&r4tst->rtsdctl, val);
> >>       /* min. freq. count, equal to 1/4 of the entropy sample length
> >> */
> >>       wr_reg32(&r4tst->rtfrqmin, ent_delay >> 2);
> >> -    /* disable maximum frequency count */
> >> -    wr_reg32(&r4tst->rtfrqmax, RTFRQMAX_DISABLE);
> >> +    /* max. freq. count, equal to 16 times the entropy sample length
> >> +*/
> >> +    wr_reg32(&r4tst->rtfrqmax, ent_delay << 4);
> >>       /* read the control register */
> >>       val = rd_reg32(&r4tst->rtmctl);
> >>   start_rng:
> >
>
> --
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