In order to make sure that we always use non-stale entropy data, change the code to invalidate entropy register during RNG initialization. Signed-off-by: Aymen Sghaier <aymen.sghaier@xxxxxxx> Signed-off-by: Vipul Kumar <vipul_kumar@xxxxxxxxxx> [andrew.smirnov@xxxxxxxxx ported to upstream kernel, rewrote commit msg] Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx> Cc: Chris Healy <cphealy@xxxxxxxxx> Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx> Cc: Horia Geantă <horia.geanta@xxxxxxx> Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Cc: Iuliana Prodan <iuliana.prodan@xxxxxxx> Cc: linux-crypto@xxxxxxxxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Cc: linux-imx@xxxxxxx --- drivers/crypto/caam/ctrl.c | 11 ++++++++--- drivers/crypto/caam/regs.h | 3 ++- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c index c99a6a3b22de..22d8676dd610 100644 --- a/drivers/crypto/caam/ctrl.c +++ b/drivers/crypto/caam/ctrl.c @@ -338,8 +338,12 @@ static void kick_trng(struct platform_device *pdev, int ent_delay) ctrl = (struct caam_ctrl __iomem *)ctrlpriv->ctrl; r4tst = &ctrl->r4tst[0]; - /* put RNG4 into program mode */ - clrsetbits_32(&r4tst->rtmctl, 0, RTMCTL_PRGM); + /* + * Setting both RTMCTL:PRGM and RTMCTL:TRNG_ACC causes TRNG to + * properly invalidate the entropy in the entropy register and + * force re-generation. + */ + clrsetbits_32(&r4tst->rtmctl, 0, RTMCTL_PRGM | RTMCTL_ACC); /* * Performance-wise, it does not make sense to @@ -369,7 +373,8 @@ static void kick_trng(struct platform_device *pdev, int ent_delay) * select raw sampling in both entropy shifter * and statistical checker; ; put RNG4 into run mode */ - clrsetbits_32(&r4tst->rtmctl, RTMCTL_PRGM, RTMCTL_SAMP_MODE_RAW_ES_SC); + clrsetbits_32(&r4tst->rtmctl, RTMCTL_PRGM | RTMCTL_ACC, + RTMCTL_SAMP_MODE_RAW_ES_SC); } static int caam_get_era_from_hw(struct caam_ctrl __iomem *ctrl) diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h index 05127b70527d..c191e8fd0fa7 100644 --- a/drivers/crypto/caam/regs.h +++ b/drivers/crypto/caam/regs.h @@ -487,7 +487,8 @@ struct rngtst { /* RNG4 TRNG test registers */ struct rng4tst { -#define RTMCTL_PRGM 0x00010000 /* 1 -> program mode, 0 -> run mode */ +#define RTMCTL_ACC BIT(5) /* TRNG access mode */ +#define RTMCTL_PRGM BIT(16) /* 1 -> program mode, 0 -> run mode */ #define RTMCTL_SAMP_MODE_VON_NEUMANN_ES_SC 0 /* use von Neumann data in both entropy shifter and statistical checker */ -- 2.21.0