Hi Horia and Varun,
On Sat, Apr 16, 2022 at 10:54 AM Fabio Estevam <festevam@xxxxxxxxx> wrote:
>
> From: Fabio Estevam <festevam@xxxxxxx>
>
> Since commit 358ba762d9f1 ("crypto: caam - enable prediction resistance
> in HRWNG") the following CAAM errors can be seen on i.MX6SX:
>
> caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error
> hwrng: no data available
> caam_jr 2101000.jr: 20003c5b: CCB: desc idx 60: RNG: Hardware error
> ...
>
> This error is due to an incorrect entropy delay for i.MX6SX.
>
> Fix it by increasing the minimum entropy delay for i.MX6SX
> as done in U-Boot:
> https://patchwork.ozlabs.org/project/uboot/patch/20220415111049.2565744-1-gaurav.jain@xxxxxxx/
>
> Signed-off-by: Fabio Estevam <festevam@xxxxxxx>
> ---
> Change since v1:
> - Align the fix with U-Boot.
Actually, after thinking more about it, I realize that this issue is
not i.MX6SX specific as
I have seen reports of the same failures on i.MX6D as well.
Would it make sense to fix it like this instead?
--- a/drivers/crypto/caam/regs.h
+++ b/drivers/crypto/caam/regs.h
@@ -516,7 +516,7 @@ struct rng4tst {
};
#define RTSDCTL_ENT_DLY_SHIFT 16
#define RTSDCTL_ENT_DLY_MASK (0xffff << RTSDCTL_ENT_DLY_SHIFT)
-#define RTSDCTL_ENT_DLY_MIN 3200
+#define RTSDCTL_ENT_DLY_MIN 12000
#define RTSDCTL_ENT_DLY_MAX 12800
u32 rtsdctl; /* seed control register */
union {
Any drawbacks in using this generic approach?
Please advise.
