diff options
| author | Alex Porosanu <alexandru.porosanu@freescale.com> | 2014-08-11 08:40:15 (GMT) |
|---|---|---|
| committer | Matthew Weigel <Matthew.Weigel@freescale.com> | 2014-12-11 18:40:55 (GMT) |
| commit | 6986486cabf73178a8fb72cdd1c18f84692df473 (patch) | |
| tree | 6a9934a60d779d73d9321657f22580dbe60c6997 /drivers/crypto | |
| parent | f21fd3c0684f4bc91e95a08f67e43438f7171131 (diff) | |
| download | linux-fsl-qoriq-6986486cabf73178a8fb72cdd1c18f84692df473.tar.xz | |
crypto: caam - disable RNG oscillator maximum frequency check
The rtfrqmax & rtfrqmin set the bounds of the expected frequency of the
oscillator, when SEC runs at its maximum frequency. For certain platforms
(f.i. T2080), the oscillator is very fast and thus if the SEC runs at
a lower than normal frequency, the ring oscillator is incorrectly detected
as being out of bounds.
This patch effectively disables the maximum frequency check, by setting a
high enough maximum allowable frequency for the oscillator. The reasoning
behind this is that usually a broken oscillator will run too slow
(i.e. not run at all) rather than run too fast.
Signed-off-by: Alex Porosanu <alexandru.porosanu@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
(cherry picked from commit b061f3fefcffa0cdcdc61ae2a1123a4e7697d452)
Change-Id: I796cf92bf08c66d0499bfe3962dcd67afd51a72e
Reviewed-on: http://git.am.freescale.net:8181/23838
Tested-by: Review Code-CDREVIEW <CDREVIEW@freescale.com>
Reviewed-by: Horia Ioan Geanta Neag <horia.geanta@freescale.com>
Reviewed-by: Matthew Weigel <Matthew.Weigel@freescale.com>
Diffstat (limited to 'drivers/crypto')
| -rw-r--r-- | drivers/crypto/caam/ctrl.c | 4 | ||||
| -rw-r--r-- | drivers/crypto/caam/regs.h | 1 |
2 files changed, 3 insertions, 2 deletions
diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c index 17af050..c2f1fd7 100644 --- a/drivers/crypto/caam/ctrl.c +++ b/drivers/crypto/caam/ctrl.c @@ -359,8 +359,8 @@ 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); - /* max. freq. count, equal to 8 times the entropy sample length */ - wr_reg32(&r4tst->rtfrqmax, ent_delay << 3); + /* disable maximum frequency count */ + wr_reg32(&r4tst->rtfrqmax, RTFRQMAX_DISABLE); /* put RNG4 into run mode */ clrbits32(&r4tst->rtmctl, RTMCTL_PRGM); } diff --git a/drivers/crypto/caam/regs.h b/drivers/crypto/caam/regs.h index 79d2bf3..dde2e1a 100644 --- a/drivers/crypto/caam/regs.h +++ b/drivers/crypto/caam/regs.h @@ -294,6 +294,7 @@ struct rng4tst { u32 rttotsam; /* PRGM=0: total samples register */ }; u32 rtfrqmin; /* frequency count min. limit register */ +#define RTFRQMAX_DISABLE (1 << 20) union { u32 rtfrqmax; /* PRGM=1: freq. count max. limit register */ u32 rtfrqcnt; /* PRGM=0: freq. count register */ |