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authorAlex Porosanu <alexandru.porosanu@freescale.com>2015-05-05 16:48:35 +0300
committerYork Sun <yorksun@freescale.com>2015-08-03 12:06:37 -0700
commitc4065517362ae9132ceaaec4103ed5ad6c9cfe92 (patch)
tree8097d230210383abf9e40d1b036d1de01c0f8a31 /drivers/crypto
parent17649e1b94b450f1ab0de7fa14553f390285f291 (diff)
drivers/crypto/fsl: enable raw data instead of von Neumann data
The sampling of the oscillator can be done in multiple modes for generating the entropy value. By default, this is set to von Neumann. This patch changes the sampling to raw data, since it has been discovered that the generated entropy has a better 'quality'. Signed-off-by: Alex Porosanu <alexandru.porosanu@freescale.com> Acked-by: Ruchika Gupta<ruchika.gupta@freescale.com> Reviewed-by: York Sun <yorksun@freescale.com>
Diffstat (limited to 'drivers/crypto')
-rw-r--r--drivers/crypto/fsl/jr.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/crypto/fsl/jr.c b/drivers/crypto/fsl/jr.c
index aa527ec954..35606688af 100644
--- a/drivers/crypto/fsl/jr.c
+++ b/drivers/crypto/fsl/jr.c
@@ -408,8 +408,17 @@ static void kick_trng(int ent_delay)
sec_out32(&rng->rtfreqmin, ent_delay >> 2);
/* disable maximum frequency count */
sec_out32(&rng->rtfreqmax, RTFRQMAX_DISABLE);
+ /* read the control register */
+ val = sec_in32(&rng->rtmctl);
+ /*
+ * select raw sampling in both entropy shifter
+ * and statistical checker
+ */
+ sec_setbits32(&val, RTMCTL_SAMP_MODE_RAW_ES_SC);
/* put RNG4 into run mode */
- sec_clrbits32(&rng->rtmctl, RTMCTL_PRGM);
+ sec_clrbits32(&val, RTMCTL_PRGM);
+ /* write back the control register */
+ sec_out32(&rng->rtmctl, val);
}
static int rng_init(void)