Hi Gaurav, I've tested 3 i.MX6DL devices over ~day and got these results (decimal values). RTMCTL: 12289 all cases RTSTATUS: device A 1 x 49152 10 x 32768 device B 13 x 32768 1 x 49152 1 x 1024 1 x 2048 device C 1 x 32768 Regards, Petr On Thu, 13 Jan 2022 at 08:23, Gaurav Jain <gaurav.jain@xxxxxxx> wrote: > > Hello Michal > > > > > -----Original Message----- > > From: Michal Vokáč <michal.vokac@xxxxxxxxx> > > Sent: Friday, November 12, 2021 8:57 PM > > To: Horia Geanta <horia.geanta@xxxxxxx>; Pankaj Gupta > > <pankaj.gupta@xxxxxxx>; Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > > Cc: David S. Miller <davem@xxxxxxxxxxxxx>; linux-crypto@xxxxxxxxxxxxxxx; > > linux-kernel@xxxxxxxxxxxxxxx; l.stach@xxxxxxxxxxxxxx; > > robert.hancock@xxxxxxxxxx; Petr Benes <petr.benes@xxxxxxxxx>; > > petrben@xxxxxxxxx; Michal Vokáč <michal.vokac@xxxxxxxxx> > > Subject: [EXT] [RFC PATCH] crypto: caam - restore retry count after HW RNG > > failure > > > > Caution: EXT Email > > > > From: Petr Benes <petr.benes@xxxxxxxxx> > > > > Each time TRNG generates entropy, statistical tests are run. > > If they fail, RETRY_COUNT value is decremented. Once it reaches 0, HW RNG > > returns an error, and needs to be reset. > > The least-significant 16 bits of the RTSTATUS register reflect the result of each of statistical tests. > Can you dump RTSTATUS to see which test has failed? Please dump RTMCTL as well. > > Have you tried to build this patch for armv8? For me it is failing. > > Regards > Gaurav Jain > > > RETRY_COUNT could be programmed in RTSCMISC register and is set to 1 by > > default. Hence, we are left without hwrng after the first error, which could > > happen even under normal conditions. > > > > Cc: petrben@xxxxxxxxx > > Signed-off-by: Petr Benes <petr.benes@xxxxxxxxx> > > Signed-off-by: Michal Vokáč <michal.vokac@xxxxxxxxx> > > --- > > Hi, > > we are also experiencing this issue: > > > > caam_jr 2101000.jr0: 20003c5b: CCB: desc idx 60: RNG: Hardware error. > > > > It is happening on both i.MX6S and i.MX6DL SoCs we use. > > On Solo I can reproduce it really fast. Sometimes it happens right after the board > > is NFS booted, sometimes I need to stress the HWRNG for a while (generate few > > hundred KBs of random data). On some DualLite SoCs it is happening at least > > once a day. > > > > We are using the v5.10 LTS branch but I can confirm that this is happening on all > > kernels since v5.7 to the latest linux-next. > > > > We also tried to increase the RTSDCTL_ENT_DLY_MIN delay as suggested in this > > thread [1]. It helped and the issue never occurred since then but we are looking > > for more universal and permanent solution suitable for upstream, hence we > > came up with this patch. > > > > Any comments will be appreciated. > > Thanks, Michal > > > > [1] > > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.org > > %2Flkml%2F2021%2F8%2F30%2F296&data=04%7C01%7Cpankaj.gupta%40 > > nxp.com%7C5d6bf460b260415aeda008d9a5f0ffab%7C686ea1d3bc2b4c6fa92cd > > 99c5c301635%7C0%7C0%7C637723276775699794%7CUnknown%7CTWFpbGZs > > b3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0 > > %3D%7C1000&sdata=VxN9MqDFbISptW3OX9XTtZ%2FwQTsEbF6dETxXB%2 > > BHrywg%3D&reserved=0 > > > > drivers/crypto/caam/caamrng.c | 42 ++++++++++++++++++++++++++++++++--- > > drivers/crypto/caam/ctrl.c | 13 +++++++++++ > > drivers/crypto/caam/ctrl.h | 2 ++ > > 3 files changed, 54 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/crypto/caam/caamrng.c b/drivers/crypto/caam/caamrng.c > > index 77d048dfe5d0..2be5584ae591 100644 > > --- a/drivers/crypto/caam/caamrng.c > > +++ b/drivers/crypto/caam/caamrng.c > > @@ -21,6 +21,7 @@ > > #include "desc_constr.h" > > #include "jr.h" > > #include "error.h" > > +#include "ctrl.h" > > > > #define CAAM_RNG_MAX_FIFO_STORE_SIZE 16 > > > > @@ -113,6 +114,35 @@ static int caam_rng_read_one(struct device *jrdev, > > return err ?: (ret ?: len); > > } > > > > +static void caam_rng_retry_reset(struct caam_rng_ctx *context) { > > + struct device *ctrldev = context->ctrldev; > > + struct caam_drv_private *ctrlpriv = dev_get_drvdata(ctrldev); > > + struct caam_ctrl __iomem *ctrl; > > + struct rng4tst __iomem *r4tst; > > + u32 __iomem *rtstatus; > > + u32 retry_count; > > + > > + ctrl = (struct caam_ctrl __iomem *)ctrlpriv->ctrl; > > + r4tst = &ctrl->r4tst[0]; > > + > > + /* > > + * There is unfortunately no member for RTSTATUS register in > > + * struct rng4tst and the structure doesn't look stable > > + */ > > + rtstatus = (u32 *)((char *)&ctrl->r4tst[0] + 0x3C); > > + retry_count = (rd_reg32(rtstatus) >> 16) & 0xf; > > + dev_dbg(ctrldev, "CAAM RNG retry count %d\n", retry_count); > > + if (retry_count == 0) { > > + dev_err(ctrldev, "CAAM RNG resetting retry count to 1\n"); > > + clrsetbits_32(&r4tst->rtmctl, 0, RTMCTL_PRGM | RTMCTL_ACC); > > + wr_reg32(&r4tst->rtscmisc, (rd_reg32(&r4tst->rtscmisc) & 0x7f) | (1 << > > 16)); > > + clrsetbits_32(&r4tst->rtmctl, RTMCTL_PRGM | RTMCTL_ACC, > > + RTMCTL_SAMP_MODE_RAW_ES_SC); > > + caam_reinstantiate_rng(ctrldev); > > + } > > +} > > + > > static void caam_rng_fill_async(struct caam_rng_ctx *ctx) { > > struct scatterlist sg[1]; > > @@ -129,8 +159,10 @@ static void caam_rng_fill_async(struct caam_rng_ctx > > *ctx) > > sg[0].length, > > ctx->desc_async, > > &done); > > - if (len < 0) > > + if (len < 0) { > > + caam_rng_retry_reset(ctx); > > return; > > + } > > > > kfifo_dma_in_finish(&ctx->fifo, len); } @@ -145,13 +177,17 @@ static void > > caam_rng_worker(struct work_struct *work) static int caam_read(struct hwrng > > *rng, void *dst, size_t max, bool wait) { > > struct caam_rng_ctx *ctx = to_caam_rng_ctx(rng); > > - int out; > > + int out, ret; > > > > if (wait) { > > struct completion done; > > > > - return caam_rng_read_one(ctx->jrdev, dst, max, > > + ret = caam_rng_read_one(ctx->jrdev, dst, max, > > ctx->desc_sync, &done); > > + if (ret < 0) > > + caam_rng_retry_reset(ctx); > > + > > + return ret; > > } > > > > out = kfifo_out(&ctx->fifo, dst, max); diff --git a/drivers/crypto/caam/ctrl.c > > b/drivers/crypto/caam/ctrl.c index ca0361b2dbb0..e421f8d1982b 100644 > > --- a/drivers/crypto/caam/ctrl.c > > +++ b/drivers/crypto/caam/ctrl.c > > @@ -339,6 +339,19 @@ static int instantiate_rng(struct device *ctrldev, int > > state_handle_mask, > > return devm_add_action_or_reset(ctrldev, devm_deinstantiate_rng, > > ctrldev); } > > > > +/* > > + * caam_reinstantiate_rng - reinstantiates RNG. Intended for a case when RNG > > falls into > > + * HW error condition. That happens if TRNG fails statistical > > + * check and RTY_CNT value set in RTSCMISC decrements to zero. > > + * It is exported to caamrng.c > > + * @ctrldev - pointer to device > > + */ > > + > > +int caam_reinstantiate_rng(struct device *ctrldev) { > > + return instantiate_rng(ctrldev, 0, 0); } > > + > > /* > > * kick_trng - sets the various parameters for enabling the initialization > > * of the RNG4 block in CAAM > > diff --git a/drivers/crypto/caam/ctrl.h b/drivers/crypto/caam/ctrl.h index > > f3ecd67922a7..26ff5a49a865 100644 > > --- a/drivers/crypto/caam/ctrl.h > > +++ b/drivers/crypto/caam/ctrl.h > > @@ -8,6 +8,8 @@ > > #ifndef CTRL_H > > #define CTRL_H > > > > +int caam_reinstantiate_rng(struct device *ctrldev); > > + > > /* Prototypes for backend-level services exposed to APIs */ extern bool > > caam_dpaa2; > > > > -- > > 2.25.1 >
