From: Ye Li ye.li@nxp.com
RNG parameters are reconfigured. - For TRNG to generate 256 bits of entropy, RNG TRNG Seed Control register is configured to have reduced SAMP_SIZE from default 2500 to 512. it is number of entropy samples that will be taken during Entropy generation. - self-test registers(Monobit Limit, Poker Range, Run Length Limit) are synchronized with new RTSDCTL[SAMP_SIZE] of 512.
TRNG time is caluculated based on sample size. time required to generate entropy is reduced and hwrng performance improved from 0.3 kB/s to 1.3 kB/s.
Signed-off-by: Ye Li ye.li@nxp.com Acked-by: Gaurav Jain gaurav.jain@nxp.com> --- drivers/crypto/fsl/jr.c | 102 +++++++++++++++++++++++++++++++++------- include/fsl_sec.h | 1 + 2 files changed, 87 insertions(+), 16 deletions(-)
diff --git a/drivers/crypto/fsl/jr.c b/drivers/crypto/fsl/jr.c index 084a61c684..15f5fd0d05 100644 --- a/drivers/crypto/fsl/jr.c +++ b/drivers/crypto/fsl/jr.c @@ -603,30 +603,100 @@ static u8 get_rng_vid(ccsr_sec_t *sec) */ static void kick_trng(int ent_delay, ccsr_sec_t *sec) { + u32 samples = 512; /* number of bits to generate and test */ + u32 mono_min = 195; + u32 mono_max = 317; + u32 mono_range = mono_max - mono_min; + u32 poker_min = 1031; + u32 poker_max = 1600; + u32 poker_range = poker_max - poker_min + 1; + u32 retries = 2; + u32 lrun_max = 32; + s32 run_1_min = 27; + s32 run_1_max = 107; + s32 run_1_range = run_1_max - run_1_min; + s32 run_2_min = 7; + s32 run_2_max = 62; + s32 run_2_range = run_2_max - run_2_min; + s32 run_3_min = 0; + s32 run_3_max = 39; + s32 run_3_range = run_3_max - run_3_min; + s32 run_4_min = -1; + s32 run_4_max = 26; + s32 run_4_range = run_4_max - run_4_min; + s32 run_5_min = -1; + s32 run_5_max = 18; + s32 run_5_range = run_5_max - run_5_min; + s32 run_6_min = -1; + s32 run_6_max = 17; + s32 run_6_range = run_6_max - run_6_min; + u32 val; + struct rng4tst __iomem *rng = (struct rng4tst __iomem *)&sec->rng; - u32 val;
- /* put RNG4 into program mode */ - sec_setbits32(&rng->rtmctl, RTMCTL_PRGM); - /* rtsdctl bits 0-15 contain "Entropy Delay, which defines the - * length (in system clocks) of each Entropy sample taken - * */ + /* Put RNG in program mode */ + /* Setting both RTMCTL:PRGM and RTMCTL:TRNG_ACC causes TRNG to + * properly invalidate the entropy in the entropy register and + * force re-generation. + */ + sec_setbits32(&rng->rtmctl, RTMCTL_PRGM | RTMCTL_ACC); + + /* Configure the RNG Entropy Delay + * Performance-wise, it does not make sense to + * set the delay to a value that is lower + * than the last one that worked (i.e. the state handles + * were instantiated properly. Thus, instead of wasting + * time trying to set the values controlling the sample + * frequency, the function simply returns. + */ val = sec_in32(&rng->rtsdctl); - val = (val & ~RTSDCTL_ENT_DLY_MASK) | - (ent_delay << RTSDCTL_ENT_DLY_SHIFT); + val &= RTSDCTL_ENT_DLY_MASK; + val >>= RTSDCTL_ENT_DLY_SHIFT; + if (ent_delay < val) { + /* Put RNG4 into run mode */ + sec_clrbits32(&rng->rtmctl, RTMCTL_PRGM | RTMCTL_ACC); + return; + } + + val = (ent_delay << RTSDCTL_ENT_DLY_SHIFT) | samples; sec_out32(&rng->rtsdctl, val); - /* min. freq. count, equal to 1/4 of the entropy sample length */ - sec_out32(&rng->rtfreqmin, ent_delay >> 2); - /* disable maximum frequency count */ - sec_out32(&rng->rtfreqmax, RTFRQMAX_DISABLE); + + /* + * Recommended margins (min,max) for freq. count: + * freq_mul = RO_freq / TRNG_clk_freq + * rtfrqmin = (ent_delay x freq_mul) >> 1; + * rtfrqmax = (ent_delay x freq_mul) << 3; + * Given current deployments of CAAM in i.MX SoCs, and to simplify + * the configuration, we consider [1,16] to be a safe interval + * for the freq_mul and the limits of the interval are used to compute + * rtfrqmin, rtfrqmax + */ + sec_out32(&rng->rtfreqmin, ent_delay >> 1); + sec_out32(&rng->rtfreqmax, ent_delay << 7); + + sec_out32(&rng->rtscmisc, (retries << 16) | lrun_max); + sec_out32(&rng->rtpkrmax, poker_max); + sec_out32(&rng->rtpkrrng, poker_range); + sec_out32(&rng->rsvd1[0], (mono_range << 16) | mono_max); + sec_out32(&rng->rsvd1[1], (run_1_range << 16) | run_1_max); + sec_out32(&rng->rsvd1[2], (run_2_range << 16) | run_2_max); + sec_out32(&rng->rsvd1[3], (run_3_range << 16) | run_3_max); + sec_out32(&rng->rsvd1[4], (run_4_range << 16) | run_4_max); + sec_out32(&rng->rsvd1[5], (run_5_range << 16) | run_5_max); + sec_out32(&rng->rsvd1[6], (run_6_range << 16) | run_6_max); + + val = sec_in32(&rng->rtmctl); /* - * select raw sampling in both entropy shifter + * Select raw sampling in both entropy shifter * and statistical checker */ - sec_setbits32(&rng->rtmctl, RTMCTL_SAMP_MODE_RAW_ES_SC); - /* put RNG4 into run mode */ - sec_clrbits32(&rng->rtmctl, RTMCTL_PRGM); + val &= ~RTMCTL_SAMP_MODE_INVALID; + val |= RTMCTL_SAMP_MODE_RAW_ES_SC; + /* Put RNG4 into run mode */ + val &= ~(RTMCTL_PRGM | RTMCTL_ACC); + /*test with sample mode only */ + sec_out32(&rng->rtmctl, val); }
static int rng_init(uint8_t sec_idx, ccsr_sec_t *sec) diff --git a/include/fsl_sec.h b/include/fsl_sec.h index 7b6e3e2c20..2b3239414a 100644 --- a/include/fsl_sec.h +++ b/include/fsl_sec.h @@ -34,6 +34,7 @@ #if CONFIG_SYS_FSL_SEC_COMPAT >= 4 /* RNG4 TRNG test registers */ struct rng4tst { +#define RTMCTL_ACC 0x20 #define RTMCTL_PRGM 0x00010000 /* 1 -> program mode, 0 -> run mode */ #define RTMCTL_SAMP_MODE_VON_NEUMANN_ES_SC 0 /* use von Neumann data in both entropy shifter and