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/
Fixes: 358ba762d9f1 ("crypto: caam - enable prediction resistance in HRWNG")
Signed-off-by: Fabio Estevam <festevam@xxxxxxx>
---
Changes since v2:
- Added Fixes tag. (Horia)
Change since v1:
- Align the fix with U-Boot.
drivers/crypto/caam/ctrl.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
index ca0361b2dbb0..c515c20442d5 100644
--- a/drivers/crypto/caam/ctrl.c
+++ b/drivers/crypto/caam/ctrl.c
@@ -648,6 +648,8 @@ static int caam_probe(struct platform_device *pdev)
return ret;
}
+ if (of_machine_is_compatible("fsl,imx6sx"))
+ ent_delay = 12000;
/* Get configuration properties from device tree */
/* First, get register page */
@@ -871,6 +873,15 @@ static int caam_probe(struct platform_device *pdev)
*/
ret = instantiate_rng(dev, inst_handles,
gen_sk);
+ /*
+ * Entropy delay is calculated via self-test method.
+ * Self-test is run across different voltages and
+ * temperatures.
+ * If worst case value for ent_dly is identified,
+ * the loop can be skipped for that platform.
+ */
+ if (of_machine_is_compatible("fsl,imx6sx"))
+ break;
if (ret == -EAGAIN)
/*
* if here, the loop will rerun,
--
2.25.1
